Nuclear Notes is produced by the Breakthrough Institute, and covers the policy, regulation, technology, and business of advanced nuclear energy in the United States and beyond.

Every Thursday, we track what’s really going on in the field: the new rules moving through the Nuclear Regulatory Commission, the advanced reactors moving from design to deployment, the companies going public and the utilities merging, and the executive orders and acts of Congress reshaping how the country builds. We explain not just what happened, but why it matters and how the pieces fit together.

Share Nuclear Notes

A Boiling-Water SMR Gets a Construction Permit in Tennessee

The Nuclear Regulatory Commission has issued a construction permit to the Tennessee Valley Authority for a GE Vernova Hitachi BWRX-300, at a site called Clinch River, in Oak Ridge, Tennessee.

The TVA has been eager to build on the 935-acre site for years; in 2019 it became the first utility in the country to get pre-approval for a reactor there, without specifying what kind.

The NRC issued the permit very fast by nuclear standards, in 14 months, four months ahead of schedule, demonstrating increased efficiency at the agency. The license decision follows faster-than-expected action on several other applications.

One factor in fast action was using a pre-approved site, an approach that could speed up project development elsewhere.

“Clinch River is an important signal toward efficient reviews becoming routine rather than the exception,” said Adam Stein, Director of Nuclear Energy Innovation at the Breakthrough Institute, in a statement. “But predictability matters as much as speed,” he said. “Applicants need to know what information the NRC expects, when decisions will be made, and that the review will remain focused on what issues matter to public health and safety. The next challenge is making efficient licensing repeatable across a growing pipeline of various kinds of reactor applications.”

The construction permit has an odd distinction: It’s the first since the late 1970s issued to a utility, although utilities used to be the conventional party for building reactors. The agency has issued permits for research reactors to various institutions, and to two reactor developers: Kairos Power, for two salt-cooled high-temperature demonstration projects, Hermes 1 and 2, also in Oak Ridge; and TerraPower, in Kemmerer, Wyoming, for its Natrium fast reactor and energy storage system.

The NRC is also evaluating a construction permit application filed in March 2025 from X-energy, another non-utility, for a high-temperature gas-graphite reactor. The reactor, called Xe-100, would provide steam to a Dow chemical plant in Seadrift, Texas.

The Xe-100, Hermes, and Natrium are all Gen IV plants, moving beyond light-water into more innovative designs. But the BWRX set for Clinch River is based on a conventional Boiling Water Reactor (BWR) with the Roman numeral X added to designate it as tenth generation. Currently operating plants are known as Gen III, and the BWRX is Gen III+, incorporating passive safety systems. Emergency cooling is simplified by the reactor’s smaller size, 300 megawatts. The design also has some innovative construction techniques intended to reduce construction time and cost.

Among these construction techniques are “steel bricks,” which are composite structures that the plant will use in place of concrete in some locations. These bricks will substitute steel reinforcing bars in the concrete, cutting labor costs and construction time.

Because the BWRX is less of a technological leap than the Gen IV reactors, it may be poised for multiple additional orders from utilities that prefer refinements of already-tested technologies over exciting new concepts. GE Vernova-Hitachi says that 90 percent of the components of the BWRX are already in use in the nuclear industry. And the design has 80 percent less output than GE’s biggest design, with 90 percent less steel and concrete.

The BWRX-300 is also already under construction: Ontario Power Generation started work on a BWRX reactor in May 2025 at its Darlington site, on Lake Ontario, and has plans for three more. BWXT Canada, a subsidiary of the U.S. company of the same name, will build reactor vessels for the BWRX in Canada.

Numerous other customers are eyeing the BWRX-300. American Electric Power, Duke, and Sask Power are among potential customers. That reactor design also appears to be one of a handful of candidates for construction in New York, where the New York Power Authority has been told by the governor, Kathy Hochul, to build one gigawatt of new capacity using conventional technology.

The NRC, the TVA, Ontario Power Generation, the Canadian Nuclear Safety Commission, and GE Vernova-Hitachi have been cooperating closely with a goal of smoothing the licensing of the design in the United States. The president and chief executive of the TVA from April 2019 until April 2025 was Jeffrey Lyash, who was a former president and CEO of Ontario Power Generation.

The TVA has faced challenges getting to this point though. President Trump fired several members of the agency’s board last year, leaving it without a quorum from April until January of this year. Congress set a limit of $30 billion on the agency’s debt, and in its most recent report the agency counts a debt of $23.8 billion.

The projects in Darlington and Clinch River may be a chance to demonstrate the economics of small modular reactors, which reverse the old logic of reactor construction that big reactors had better economics. Ontario Power Generation is projecting a cost of about $7.7 billion (Canadian) or $5.4 billion (U.S.) for the first unit, which comes to $18,000 (U.S.) per kilowatt of capacity–a high number–with sharp reductions for subsequent projects.

Dig Deeper

Despite Proliferation Worries, a Saudi Deal Gets Some Backing

For nearly two decades, scholars and policymakers have warned about the risks of a civilian nuclear deal with Saudi Arabia. But that consensus may be changing. Among others, two researchers at Columbia University’s Center on Global Energy Policy have recently concluded that a Trump Administration deal to cooperate with the Kingdom of Saudi Arabia on civil nuclear projects would serve U.S. interests, despite the fact that it “has broken a decades-long U.S. nonproliferation taboo” because it does not include a prohibition on Saudi uranium enrichment.

Saudi Arabia says it wants nuclear reactors so it can reduce its use of fossil fuels, preserving more for export. It is also in informal competition with the United Arab Emirates, which has commissioned four large pressurized-water reactors of Korean design.

Notably, the UAE agreed not to enrich uranium and signed its 123 agreement in 2009 that has become known as the “gold standard,” under which it will import the fuel and export the spent fuel, which contains plutonium, although in a form that is difficult to use in weapons.

Saudi Arabia, in contrast, has historically refused to sign a deal that bars it from enrichment capabilities. The country has said it wants a nuclear program that includes not only reactors but fuel manufacturing. This has been the sticking point in the negotiations for years, especially since Crown Prince Mohammed bin Salman has stated publicly that Saudi Arabia would develop nuclear weapons if its neighbor Iran does. In September, Saudi Arabia announced that it had found 110 million metric tons of uranium-bearing ore.

But the Columbia researchers found that “the agreement contains several novel components that can help mitigate nonproliferation risks and offer significant benefits to U.S. national interests.” One is that Saudi Arabia will use “qualified suppliers” approved by the U.S. The agreement also calls for a lengthy study of enrichment, and bars centrifuge technology from being transferred to Saudi Arabia without additional negotiations. Another provision is a bilateral safeguards agreement.

The United States is eager to sell American-designed reactors to Saudi Arabia, specifically the Westinghouse AP1000. The consensus is that Saudi Arabia is likely just as eager for American technology and the additional areas of cooperation that come with signing such a deal with the U.S.

The Trump administration submitted the deal to Congress in August, and it will enter into force after 90 days of congressional session, unless both chambers object. But Congress cannot act before election day because the House has already ended its session, and time will be short in the lame duck session at the end of the year.

Dig Deeper

“Project Power” – $120 Billion Proposed for Eight New Nuclear Reactors

The United States and South Korea announced a framework for up to $120 billion in Korean investment to build eight large nuclear reactors in the United States: six Westinghouse AP1000s and two Korean-designed APR1400s. About $100 billion is earmarked for construction, with another $20 billion reserved for contingencies. Korea could also provide up to $10 billion by the end of this year, subject to legal approvals, to begin ordering long-lead equipment.

The APR1400 is already certified by the NRC, and Korea is eager to enter the U.S. market, with hardware or project management expertise. But such investment deals are announced more often than they are consummated; a year ago the Trump administration announced a deal for Japan to invest $80 billion in the U.S. nuclear sector, but the status of that program is unclear.

Dig Deeper

A Start-Up Seeks a License to Enrich Uranium

General Matter, a two-year-old California company, has applied to the NRC for permission to build an enrichment plant that it says will eventually make high-assay low-enriched uranium, or HALEU, the type that most advanced reactor designs require.

A year ago, the company announced that it had leased land from the Energy Department at Paducah: the site where the Atomic Energy Commission formerly used gaseous diffusion to enrich uranium. If built, it would be only the second American-owned enrichment plant. The United States imports most of enriched fuel, and some is produced at a European-owned plant in New Mexico. Plans for new reactors have exposed a shortage of enrichment capability, exacerbated by a decision to bar uranium enriched in Russia.

The company—which has backing from Peter Thiel and other investors—already has a $900 million contract from the Energy Department. The co-founder and CEO, Scott Nolan, was an early employee at SpaceX.

Dig Deeper

Nuclear Life Extension Has the Best Economics…

The Nuclear Energy Agency, part of the Organisation for Economic Co-operation and Development, and the Electric Power Research Institute, a non-profit utility consortium, have analyzed 23 different electricity- generating technologies in 21 countries, and concluded that extending generation at currently operating reactors would result in the least expensive cost of energy. Other contenders include large-scale reactors that are not the first of their kind to be built, solar photovoltaics (with or without batteries), and pumped hydro storage systems. But its annual survey observes that onshore wind and solar photovoltaic systems “remain attractive at the level of the individual plant, although compared to past editions, no significant further cost decreases have been observed.” And costs are higher “if their system costs are included.”

Dig Deeper

…And Increasing the Output of Older Reactors Works Well Too

Georgia Power announced that Google will spend about $900 million to expand the output of two of its nuclear facilities—Vogtle Electric Generating Plant Units 1 and 2, near Augusta, and Hatch Nuclear Power Plant, near Baxley—by a combined 96 megawatts.

The agreement, which is subject to the approval of the Georgia Public Service Commission, would add energy to the Georgia grid. Google would get clean energy credits, advancing its goal of reaching net zero carbon emissions by 2030.

Dig Deeper

Thanks for reading!

Share Nuclear Notes

Nuclear Notes is produced by the Breakthrough Institute, and covers the policy, regulation, technology, and business of advanced nuclear energy in the United States and beyond.

Every Thursday, we track what’s really going on in the field: the new rules moving through the Nuclear Regulatory Commission, the advanced reactors moving from design to deployment, the companies going public and the utilities merging, and the executive orders and acts of Congress reshaping how the country builds. We explain not just what happened, but why it matters and how the pieces fit together.

Share Nuclear Notes

A New Calculation of Nuclear Costs Makes Reactors Cheaper Than Gas Plants

Analysts who estimate the cost of future nuclear reactors based on Georgia Power’s Vogtle 3 & 4 are using the wrong yardstick, according to a new paper by Charles Komanoff, a longtime nuclear skeptic turned advocate, and James Boucher, a climate policy analyst.

Vogtle’s two new Westinghouse AP1000 reactors took 14 years to build and cost about double what they were supposed to, and are obvious reference points because they are the most recent builds. But they are outliers, the researchers argue, because, although they were twins, they were hit by the COVID pandemic, the Westinghouse bankruptcy, the fact that they were first- and second-of-a-kind, and other factors.

Far better insight comes from the 47 light-water reactors completed in this country in the 1980s and early 1990s, the researchers said. They tease apart the large cost variations among those reactors to distill insights into how to minimize the cost of new ones.

However, of those 47 reactors, many of them were also late and over budget, and hit by higher interest rates than prevail now, which made delays even more costly. Other factors are similar: supply chain constraints, including both hardware and skilled craft labor, lack of experience in the management of complex projects, and the details of new designs. But the authors’ contention is that there are lessons in the variation among those construction projects.

Some of the arguments are familiar: standardization and building twins or triplets cut costs, as does using an “orderbook approach” (i.e., doing the same job over and over). The Breakthrough Institute has previously endorsed the orderbook idea.

Among their findings:

• Projects with mostly standardized designs had costs 29 percent lower than projects that didn’t

• Plants with twin or triplet reactors at a single site had an average cost approximately 20 percent lower than sites with one reactor

• Projects built with an “orderbook” approach, with multiple projects and a standardized design, drove down costs

• Reactors were easier to build in periods where regulations were stable, a condition likely to be achieved now in the United States

New reactors can be built for an average cost of $8,200 a kilowatt or less, the researchers found. Vogtle cost $16,350 a kilowatt. Both figures are “overnight costs,” not counting the expense of interest during construction. Those interest costs appear poised to rise, because rates are rising, but the new research also gives clues about how to hold them to a minimum, by speeding up construction.

The paper’s cost estimates are about 30 percent lower than the estimates in a recent joint report by the New York State Energy Research and Development Authority and the Department of Public Service. And it notes that reactors built in the South were generally less expensive than those built elsewhere, but says it cannot explain why. It also casts doubt on the metric that is often used to compare the costs of competing technology: levelized cost of energy (LCOE). LCOE is calculated by adding up the capital, fuel, and operating costs, and dividing by the amount of energy produced. But that measure does not help evaluate the ability of technologies to contribute to another goal, “running an entire system that has to be exquisitely reliable at all times.”

The report proposes another measure for the value of a plant: comparison with the social cost of carbon, which is an estimate of the economic damage caused by burning fossil fuels, per ton of CO₂. During the Biden administration, the Environmental Protection Agency put that at $480 per ton (The Trump administration has rejected the whole concept.) A megawatt-hour of electricity from an efficient gas-fired plant thus has a social cost of just under $200. But a new reactor can produce electricity for $110 to $190 a megawatt hour, they found.

How much these calculations will be incorporated into construction decisions is not clear, but they do provide a theoretical basis for a more optimistic estimate about new nuclear reactors. And they put numbers on factors that are generally recognized as helpful, like building multiple copies of the same reactor, at fewer locations.

Dig Deeper

One Giant Nuclear IPO Hits Pause but Another Marches On

With growing talk on Wall Street of an artificial intelligence bubble, Holtec has delayed an initial public offering that could have valued the company at $10 billion, citing “uncertainty of data center development.” But Westinghouse appears to be pressing forward and seeking a valuation of more than $50 billion, a tidy sum for a company that declared bankruptcy in March 2017. Brookfield Business Partners, a Canadian turnaround firm, and some partners bought Westinghouse for about $4.6 billion. Six years later, Brookfield sold 49 percent of the business to Cameco, a Canadian uranium mining firm, in a transaction that valued the company at about $8 billion.

Brookfield’s share was valued at $2.3 billion, Cameco’s at $2.2 billion, and the companies assumed another $3.4 billion in Westinghouse’s debt. Elements of the turnaround include the completion of Georgia Power’s Vogtle 3 & 4, the twin AP1000 project that bankrupted Westinghouse, and those reactors’ successful start-up. And the Department of Energy has conditionally decided to loan $17.5 billion for the fabrication of major components for ten AP1000 units.

But among the potential beneficiaries of a $50 billion valuation is the U.S. government, which, in exchange for past help to the company, could take 20 percent of cash distributions made by Westinghouse to its investors over $17.5 billion. Or the government could end up owning stock in the company.

Westinghouse has always been valuable because it has a profitable business serving reactors it has sold over the years. But the much higher valuation it is now seeking is based on the prospect of sales of numerous additional AP1000 models here and in Europe.

But on Wall Street, where the motivations are often described as alternating between greed and fear, there is anxiety at the moment.

As reported last week, Holtec pulled back amid a general retreat of companies related to data centers that were seeking to go public. The New York Times recently reported that SB Energy, a subsidiary of SoftBank, which had proposed building the biggest data center in the world in Ohio, has delayed what was expected to be a $50 billion IPO. So has Aggreko, a company that provides electricity to data centers, the Times reported. Anthropic, the AI company, has delayed a major filing that is needed to go public, at least briefly.

Meanwhile, X-energy went public on April 26, at $23 per share and surged to over $30, but this week was trading at under $17. X-energy plans to build a high-temperature reactor at a Dow chemical plant in Texas, to provide steam that is now made by burning natural gas. NuScale Power, which has a small modular reactor design licensed by the Nuclear Regulatory Commission, went public in May, 2022, at about $10 a share. A year ago it was selling for more than $57 a share, but it is now trading under $9.

Dig Deeper

TerraPower and Bechtel Will “Move Forward Separately”

TerraPower, which is building a sodium fast reactor with a molten-salt energy storage system, has parted ways with Bechtel, the veteran engineering and procurement contractor, at the Natrium project, the two companies said.

Neither said why.

Bechtel assisted TerraPower through several key steps, including getting a construction permit from the NRC. TerraPower said it did not expect the decision to delay construction.

Dig Deeper

Deep Underground, an Unusual Reactor Design

Deep Fission, the company that plans to lower a small nuclear reactor into a well a mile deep and use the earth itself as the containment, has just taken two unusual steps: it has publicly released its Nuclear Safety Design Agreement, the document it submitted to the Department of Energy to win approval for testing on DOE property, and it has proposed a reactor without control rods.

The company has previously described its design as including four standard pressurized water reactor fuel bundles. But in a traditional reactor, control rods are lowered among the fuel assemblies to choke off the flow of neutrons. Deep Fission’s safety document describes a “soluble neutron absorber in a concentration high enough to rapidly shut down the reactor.” Among the questions for safety regulators may be how to promptly deliver the liquid from the surface, a mile above.

Dig Deeper

Kairos Gets an Investor/Supplier

Samsung Construction & Trading Corporation, an engineering firm that is part of the Korean manufacturing conglomerate, will take an equity position in Kairos Power and provide engineering services, with a total value of up to $100 million, the two companies said. Samsung will help build Kairos’ 50-megawatt demonstration reactor, which is supposed to start supplying electricity to Google in 2030.

Kairos is using TRISO fuel, but instead of a gas coolant, its design calls for fluoride salt, which can absorb large amounts of heat at low pressure.

“The companies plan to collaborate on selected engineering and construction activities to strengthen technical and execution readiness, initially focused on power-generation systems and balance-of-plant scope,” according to the announcement.

Dig Deeper

Thanks for reading!

Share Nuclear Notes

Nuclear Notes is produced by the Breakthrough Institute, and covers the policy, regulation, technology, and business of advanced nuclear energy in the United States and beyond.

Every Thursday, we track what’s really going on in the field: the new rules moving through the Nuclear Regulatory Commission, the advanced reactors moving from design to deployment, the companies going public and the utilities merging, and the executive orders and acts of Congress reshaping how the country builds. We explain not just what happened, but why it matters and how the pieces fit together.

Share Nuclear Notes

The Bad Guesses That Led to Yucca Mountain

Advocates for burying spent nuclear fuel at Yucca Mountain say it was chosen because the site, about 100 miles from Las Vegas, was remote, dry, and capable of holding in the radioactive material for millennia.

Those statements about Yucca are true, but the four other sites under consideration before Congress chose Yucca also comfortably met the safety standard established by the Department of Energy. According to a re-analysis by Dr. Adam Stein, the Breakthrough Institute’s Director of Nuclear Energy Innovation, Yucca outranked the other sites because the estimate was that it would be less expensive to build there than at the other finalist sites: Deaf Smith County in Texas, Richton Dome in Mississippi, Davis Canyon in Utah, or Hanford, in Washington State.

And the cost estimates were far from precise. The Energy Department’s 1986 estimate put the cost of building and operating the Yucca repository at $7.5 billion, but by 2008 it was over $96 billion. Even with inflation, the original estimate was not meaningful.

The cost estimates for the other sites were also just that, estimates. They were stated in ranges, and if the analysts had used the upper bound of the cost estimates, the ranking would have changed.

Estimates of repository costs accounted for nearly 88 percent of the differences among the sites, which is important because the estimates were probably of very poor quality. The DOE had not characterized any of the sites when it made the cost estimates, so the estimates themselves were unreliable.

“The cost estimate was too uncertain to serve as a decision point,” Dr. Stein concluded. The weighting was “concentrated in a single uncertain attribute,” he wrote, and the result was to “indicate robustness that the model does not have.”

Congress passed the Nuclear Waste Policy Act in 1982, and the Energy Department studied nine sites. By 1985, the Energy Department had winnowed this down to three sites, but in 1987, Congress amended the law to tell the Energy Department to evaluate just one, Yucca. Yucca was ranked first, which let lawmakers from other states go home to tell their constituents that they had picked the top-ranked site and that the repository would not be built in their states. But Nevada eventually fought off Yucca, largely through the efforts of Senator Harry Reid, who became the Senate Majority Leader. Reid maneuvered to cut off funding from the program, and Senator Barack Obama, running for president, pledged to kill it. The result is that the government’s high level waste program has been dormant for years, and spent fuel is stored at the reactor sites, at a cost to the federal government approaching $1 billion a year.

Now, through the Nuclear Lifecycle Innovation Campus initiative, the Trump administration is proposing to establish several sites where used fuel could be reprocessed, recovering plutonium produced in reactor operations plus unused uranium. The residual material could potentially be disposed of at those sites.

On Tuesday, the House Energy and Commerce Committee held a hearing on nuclear spent fuel policy and to examine the NLIC program. Ted Garrish, DOE Assistant Secretary for Nuclear Energy, repeatedly stated that the law needs to be updated to allow the agency to characterize and identify potential sites; currently, only Yucca can be the U.S.’s designated waste site. In this anticipated next round of siting studies and evaluations, DOE needs to take a different tack in its comparison of sites. Dr. Stein identifies that the failed step last time was between the analysis and the ultimate decision, and recommends how exactly DOE should solve that.

Dig Deeper

A Nuclear Company Sees Uncertainty on Wall St.

Last week Holtec, following a filing with the Securities & Exchange Commission, announced plans for an initial public offering that could raise $900 million and would value the company at about $10 billion. But this week the company delayed it, amid fears of a bubble in a closely-related industry, artificial intelligence.

But even if the IPO is delayed, the documents are worth a look. Both stress how well-established Holtec is, with business lines in numerous aspects of the nuclear energy industry–a contrast to other nuclear entrants.

Holtec does not fit the legacy model embodied by Westinghouse and GE, which have decades of experience in servicing reactors, and a mostly long-past history of reactor construction, and are only now beginning to sell a new generation of designs with a cobbled-together supply chain. Nor does it fit the start-up model, with teams of smart engineers who have innovative designs for reactors with inherently better safety and performance characteristics, but no construction or operation experience.

Holtec is broader. Its capabilities include “reactor design, reactor operations, engineering, licensing, manufacturing, construction, commissioning, and decommissioning services,” says the company announcement. Its pitch to potential investors is that, with that experience, “Holtec believes that it is well-positioned to help catalyze the growth of the nuclear power industry in the U.S. and around the world.” Among its advantages is a steady stream of contracts for the massive casks used to store spent nuclear fuel.

Holtec lists its design capabilities, but perhaps its most distinctive feature is its vertically integrated approach to reactor delivery—a self-proclaimed leg up. Holtec designs, manufactures and fabricates, gets licenses, and executes. The company says it has “hundreds of completed projects delivered on-time,” although these are not complete reactors. Holtec is also on the verge of producing power from the Palisades reactor near Kalamazoo, Michigan, that it bought for decommissioning. The company wants to deploy two of its SMRs there, and the NRC just allowed preliminary site preparation.

The company has 40 years of experience in spent fuel management, holding about 90 percent of the U.S. market for components used for wet storage of spent nuclear fuel, and 76 percent of the market for dry cask storage. It also says it has 203 worldwide patents, customers in more than 40 countries on five continents, $577 million in annual revenue, and more than 4,150 employees worldwide.

As with all SEC filings, Holtec lists uncertainties and risks. For example, the company stressed its leadership in reactor decommissioning, a profitable business, but reactor owners can decide to extend their plants’ lives instead of decommissioning them. But Holtec has positioned itself in that business too. And Holtec’s SMR design is new but not audaciously different. It is seeking to launch a line of 300-megawatt units using the familiar pressurized water technology.

The IPO would have valued the company at $10 billion. Is that justified? Companies that have yet to build their first power reactors and have no industrial base or substantial lines of business generating income are valued in the billions. Oklo, which has a design for a more advanced reactor but has yet to sell one, is at $6.74 billion; NuScale Power, which has an NRC-approved design but no sales, has a market cap of about $3.5 billion.

Those companies will be commercial successes only if they can build their new reactors. Holtec seems certain to go forward whether its SMR-300 is built or not.

Dig Deeper

A New Link in the Fuel Supply Chain

An obscure but critical step in making reactor fuel is converting yellowcake, which is produced by uranium mines, into uranium hexafluoride gas, the substance that goes through centrifuges to sort the isotopes of uranium. This phase of the fuel cycle is known as conversion, before UF₆ can then be enriched. The United States has one factory that does that work, in Metropolis, Illinois, and it closed abruptly in 2017 because of poor market conditions. It was overhauled and reopened in July 2023.

Now a start-up in Idaho Falls, Idaho, Raven-Flint Nuclear Corp., is pioneering a new chemical process for conversion that is supposed to have lower costs for capital and energy. Its process has not been publicly described but is potentially safer; it eliminates use of elemental fluorine, which is highly reactive and poisonous. Its application is now being evaluated by the NRC.

Dig Deeper

A Reactor to Maneuver a Satellite in Orbit

The Pentagon has awarded $161 million to Antares, a California startup, to develop a reactor that could provide propulsion to carry out “dynamic operations that were once impossible” in orbit.

Antares achieved initial criticality for its microreactor prototype on June 4th this year. That model and the space reactor will use TRISO fuel and sodium heat pipes. The space version will produce up to 1 megawatt. It is scheduled for testing on the ground next year. The award follows an executive order issued in December 2025 that calls for a reactor in orbit as soon as 2028.

The satellites in service today that can adjust their orbits use chemical rockets to do so. But they carry limited fuel. The United States has already deployed weapons in orbit, but their usefulness is constrained by the limited ability of satellites to maneuver. A reactor would vastly improve a satellite’s ability to chase other satellites. Such a reactor could also be a prototype for reactors on the Moon or Mars, or could provide propulsion for a rocket going to Mars, reducing the duration of the trip.

Dig Deeper

NRC Overhaul Will Stretch “Well into Next Year”

The NRC’s broad reform of its rules, mandated by President Trump’s executive order of May 2025, will continue “deeper into next calendar year,” the chairman, Ho Nieh, told Reuters. And, the Commission is getting closer to its goal of approving new facilities within 18 months, he said.

Dig Deeper

Thanks for reading!

Share Nuclear Notes

Nuclear Notes is produced by the Breakthrough Institute, and covers the policy, regulation, technology, and business of advanced nuclear energy in the United States and beyond.

Every Thursday, we track what’s really going on in the field: the new rules moving through the Nuclear Regulatory Commission, the advanced reactors moving from design to deployment, the companies going public and the utilities merging, and the executive orders and acts of Congress reshaping how the country builds. We explain not just what happened, but why it matters and how the pieces fit together.

Share Nuclear Notes

Comment on Reforms: Out with the New, In with the Old

Surveys and recent votes in Congress show strong bipartisan support for nuclear energy, but that does not mean that all Democrats are completely behind recent reforms. Eleven state attorneys general, all Democrats, have signed on to comments opposing the Nuclear Regulatory Commission’s proposed reform of its radiation protection framework and its effort to fast-track procedures under the National Environmental Policy Act.

The Attorneys General are from states with mixed approaches to nuclear energy. California still has a moratorium in place on new nuclear, and has tried in the past to close its last remaining plant, Diablo Canyon. In contrast, Illinois, also a signatory, recently lifted a ban on new nuclear, and Colorado last year passed a law defining nuclear energy as a clean, non-emitting resource under state law, which could qualify a reactor for financial help. New Mexico, another signer, has a more mixed position. It has a large uranium enrichment plant, but recently blocked centralized interim storage of spent fuel.

Washington has considerable anti-nuclear sentiment, but X-energy and Energy Northwest, a public power agency, are working to develop a cluster of high-temperature small modular reactors in the eastern portion of the state. Likewise, Minnesota has had a strong anti-nuclear faction, but the state is funding a study to see if it should lift its 32-year moratorium on new reactors. The state is struggling to reach its goal of a carbon-free electricity system.

Maryland intermittently toys with the idea of another reactor at the Calvert Cliffs site. Massachusetts, another signer, was highly unfriendly to Seabrook, which is just across the state line in New Hampshire. And Vermont tried to outlaw the Vermont Yankee reactor. Both states are now cautiously reevaluating nuclear energy as part of their future power mix.

But perhaps more significant than the fact that all the attorneys general were Democrats, all were elected. Attorneys general taking a policy position like this can point to it in their next election campaign and win a few votes from people who oppose nuclear energy, and who are radiophobic. The NRC is proposing to eliminate its standard for holding radiation exposures “As Low As Reasonably Achievable,” a policy known by its initials, ALARA. The Attorney General of New Mexico, Raúl Torrez, called this “one of the most important science-based safeguards we have to minimize radiation risks,” although the standard isn’t based on science, since the doses it prevents are too small to have measurable effects, if in fact they have any.

ALARA is based on the idea that there is no threshold below which radiation has no health effect. But as the Breakthrough Institute has previously observed, real life is full of thresholds. For example, heated water from a tap has no effect on skin unless it reaches a certain temperature threshold. And imposing regulations on nuclear energy that are pointless and burdensome does have a health effect; it biases the electricity system in favor of dirtier but less-regulated fuels.

The dose saved by enforcing ALARA is tiny relative to total background dose or to the variation in dose absorbed by people depending on life choices that we don’t think of in radiation terms, like taking a lot of long-distance airline flights, which exposes a person to more radiation from space, or moving from sea level to a place like Denver, where natural background radiation is higher.

The attorneys general comment objects to changes in implementing NEPA’s notoriously cumbersome requirements for Environmental Impact Statements. They also object to “categorical exclusions,” which would exempt highly similar projects from fully individual evaluations.

But as the Breakthrough Institute points out, “If the U.S. environmental regulatory regime is to function as an effective tool for safeguarding the environment, policymakers and stakeholders alike must work to engineer a new process that supports–rather than hinders–the nation’s transition to a future of cleaner and more abundant energy and resources.”

The comments implicitly carry the idea that reforming the rules means increasing nuclear risk. In fact, the changes pave the way for a generation of nuclear technology that is inherently safer, by its use of refined designs and better materials. Among the points in the attorneys general comments that are counterintuitive is that old rules are better because they are old.

Dig Deeper

Reactor Operators Map Fresh Investments in Legacy Plants

The companies that run legacy nuclear reactors are bullish on the industry’s future, according to a survey by the Nuclear Energy Institute, the industry’s largest trade organization. Those companies want to extend their licenses, boost power production at each plant, run the plants longer between refueling shutdowns, and in some cases restart shuttered reactors.

Overall, the survey said that there would be over 7,000 megawatts of additional generation from the current fleet.

But there is a bottleneck for all this activity, the organization said. “The ability of federal agencies to sustain predictable schedules, efficient reviews, and timely decision-making will play a major role in determining how much of the planned nuclear capacity identified in this survey ultimately becomes operational.”

NEI also asked the companies whether their plans and expectations for new nuclear had expanded in the last year. Seven said yes and four said no. None said their plans or expectations had decreased.

Looking ahead 15 years, the survey showed utilities are planning for another 33.6 gigawatts of new nuclear generation, which is nearly double what was planned in 2024. Plans were split evenly between small modular reactors and large reactors.

The survey’s insights are limited by the fact that NEI was only asking its members. This survey specifically targeted 21 NEI utility member companies that operate the United States’ 94 nuclear units. Companies developing data centers have also announced plans to include reactors in their projects, but those plans are not included in the survey. NEI found that its members’ interest in “behind-the-meter” reactors at data centers “appears to have waned.”

Projects like X-energy’s high-temperature gas-cooled reactor at a Dow Chemical factory in Texas are another area of nuclear expansion that the survey may not capture. And, of course, when discussing power plants, more projects are planned than actually built.

The utilities’ planned projects for new builds run to a little over 30 gigawatts by 2039, which is a far cry from the 400 gigawatts of capacity that President Trump has called for by 2050. Current capacity is a little under 100 gigawatts.

And the survey found that NEI’s members are not so interested in hydrogen, which can be made by nuclear reactors without releasing carbon dioxide and can be used to generate electricity or industrial heat for things like chemical processing.

Dig Deeper

U.S. Loans up to $1.9 Billion for Restart of Duane Arnold

The Energy Department announced it had closed a loan with NextEra Energy to help the company restart the 615-megawatt reactor, which closed in 2020 because of adverse economics. Reopening is scheduled for Spring 2029, and Google has contracted to buy some of the energy for its data centers.

Palisades, in Michigan, and the Crane Clean Energy Center (formerly Three Mile Island 1) in Pennsylvania are also being restarted with help from federal loans.

Dig Deeper

A Different Kind of Coal-to-Nuclear Conversion

West Virginia has entered the competition to host a Nuclear Lifecycle Innovation Campus, a place where uranium could be enriched, spent nuclear fuel could be reprocessed, new fuel could be manufactured, and waste could be stored or disposed of.

The state is better known as the coal capital of America, but that industry is in severe decline; the mines still operating are so heavily mechanized that there are far fewer jobs. It has no nuclear energy plants, and missed the April 1 deadline to apply for the competition for the campuses, but lobbied to be added. Five other states are in the competition, and it is not clear how many campuses would be built.

Dig Deeper

Sail from Charleston, S.C., to Felixstowe, U.K., on Neutrons?

Many of the hurdles facing nuclear-powered freighters are not technical, but regulatory. Among the issues, ports at both ends of the journey have to agree to accept the ships.

But two major ports, on either side of the Atlantic, have announced a partnership to study the legal and operational issues, including security, cyber resilience, and emergency response. And Felixstowe is the U.K.’s biggest container port.

Marine diesel engines run continuously for long periods and produce many megawatts of power, making them promising places to substitute nuclear fuel for fossil fuel.

Dig Deeper

Thorium Goes Small

Lawrence Livermore National Laboratory and Ampera, a Florida-based startup, will explore using thorium instead of uranium in TRISO fuel, which could turn high-temperature gas reactors and microreactors into machines that make much of their own fuel.

Thorium-232 is an abundant element. It cannot sustain a chain reaction, but it can capture a neutron and eventually decay into uranium-233, which can. Previous use has involved taking the fuel out of a light-water reactor, chopping it up, and recovering the uranium for reuse, but some companies are exploring breeding the U-233 in the fuel itself.

TRISO, or tri-structural isotropic fuel, is usually made with kernels of uranium encased in concentric layers of highly heat-resistant materials. The fuel is well-suited to microreactors and to high-temperature reactors.

Part of the challenge is producing a thorium kernel with a precise size, shape, and composition. LLNL says it has developed a technology that can do that.

Dig Deeper

Thanks for reading!

Share Nuclear Notes

Nuclear Notes is produced by the Breakthrough Institute, and covers the policy, regulation, technology, and business of advanced nuclear energy in the United States and beyond.

Every Thursday, we track what’s really going on in the field: the new rules moving through the Nuclear Regulatory Commission, the advanced reactors moving from design to deployment, the companies going public and the utilities merging, and the executive orders and acts of Congress reshaping how the country builds. We explain not just what happened, but why it matters and how the pieces fit together.

Share Nuclear Notes

Military Purchases Could Launch a Microreactor Industry

The Army and the Air Force are both trying to move quickly to install microreactors, in an effort to isolate themselves from the wider electricity grid, which they see as a target for attack, and replace diesel generators, which have a vulnerable fuel supply chain.

The Army has now put serious money behind that effort. Last week, it selected five reactor companies and five initial military installations under its Janus Program, with up to $2.2 billion in awards: Westinghouse at Fort Drum, BWXT at Fort Campbell, General Atomics at Fort Hood, Antares at Fort Bragg, and Radiant at Fort Benning. The Army says it expects the program, combined with private-sector funding, to ultimately support more than 20 microreactors across Department of War installations. The Air Force also recently selected three suppliers under its Advanced Nuclear Power for Installations program, pairing Radiant with Buckley Space Force Base, Westinghouse with Malmstrom Air Force Base, and Antares with Joint Base San Antonio. The goal is to have at least one reactor operating by 2030 or sooner.

This is a new wave of military interest in nuclear power, but hardly the first. The Army operated its own nuclear power program from the 1950s through the 1970s, developing small reactors specifically to provide power and heat at remote installations. Technical advances in nuclear engineering since then have made small reactors much more feasible. And more recently, the Pentagon launched Project Pele to develop a transportable microreactor for remote military operations.

There is ample precedent for military use of a new technology to pave the way for commercial adaptation. Light-water power reactors, the kind that now make up our reactor fleet, started with naval propulsion reactors. Jet engines started with the military, NASA pioneered solar cells (although the concept was already clear), and NASA and the Pentagon pushed microchip technology.

Janus appears designed with that history in mind. Rather than simply paying companies to develop reactors, the Army is tying funding to technical milestones and requiring substantial private investment. That lets the government create an early market while leaving the suppliers and their investors to bear the risk that the technology may not work or ultimately prove competitive.

And that may be the more interesting part of what is happening now. Microreactor developers have spent years confronting the problem facing much of advanced nuclear: customers are reluctant to order an expensive first plant, while manufacturers cannot bring down costs without orders. The War Department can be a very unusual kind of first customer. It has a real need for the product, can order multiple units, and puts a premium on resilience and fuel security that an ordinary electricity buyer may not.

The Pentagon is sponsoring two categories of microreactors: transportable and fixed. Transportable means that the reactor and power conversion equipment can arrive on several trucks or rail cars or heavy-duty cargo planes and be set up in a few hours. When shut down and left to cool, it can be moved out again after a few days or weeks. Fixed means the reactor can run a few years, until it needs refueling, at which point it will be left to cool for days, and then shipped out, intact, to go back to a factory.

If the Pentagon is the launch customer for a variety of microreactors, the size of the commercial market is not yet clear. And military demand should not be confused with proof of a commercial market. The obvious market is remote communities and off-grid customers, like mines, that now rely on diesel fuel. That fuel is now well over $5 a gallon, not counting delivery charges, and in some places, delivery is a major hassle, often requiring a lot of fuel for the delivery vehicle. A diesel generator can produce only 13 or 14 kWh per gallon, which can put the fuel cost alone at about 40 cents a kilowatt-hour. In addition to energy, the military is buying reliability.

Commercial places with a high need for reliable energy could also be willing to pay premium prices. However, in that setting, a microreactor would compete with batteries or small gas turbines, so price is a big consideration.

The real test of these programs is not whether the Pentagon can get a handful of microreactors built. With enough strategic justification, it can. The test is whether those orders create repeatable products, a supplier base, lower costs, private investment, and customers willing to buy the next units without the Pentagon underwriting them.

Dig Deeper

Palisades Approaches the End of the Long Road Back

Holtec International, which bought the Palisades reactor to dismantle it, has been working instead to bring it back to life. Holtec just announced that it is finally preparing to load fuel for restart.

The company said it is in “Mode 6,” which means it has loosened the bolts so it can remove the reactor vessel head, or it has already removed it. The reactor is in “cold shut-down,” meaning its temperature is below the boiling point. Operators will use a crane to load new fuel at the periphery of the core, and move older, partly-used fuel towards the center, 204 assemblies in all.

The long road back illustrates attention to detail and safety, and the long lead time to keep plants running or make regulatory changes. Entergy shut Palisades down in May 2022, citing a tough economic situation, and Holtec bought it the following month, almost immediately seeking to reopen it. But there was a backlog of deferred maintenance because the plant had been scheduled to retire. And there was new ground to break on the regulatory front; no one had ever sought to restore an operating license after it had been surrendered to the NRC.

Palisades would seem to have had an easier path to re-opening than Three Mile Island unit 1, but both have proven difficult. Holtec had not begun dismantling Palisades, but Exelon destroyed some major components at TMI_1 now the Crane Clean Energy Center. Exelon shut that reactor in September 2019 because it said costs were higher than its revenues, and in the years before it reversed course, it cut its maintenance costs in ways that added to the difficulty of re-starting the plant.

But then the market for electricity shifted sharply. Ownership shifted to Constellation Energy when Exelon split up into a generation company and a regulated utility, and Constellation announced in September 2024 that it planned to restart the reactor. But that job requires major new equipment purchases and completely new fuel. Constellation hopes to reopen next year.

Several other reactors were closed prematurely during the years of hardly any load growth and exceptionally cheap natural gas. The third plant seeking to restart is Duane Arnold, which shut in August 2020. Its owner hopes to apply for an operating license in the next two months. Other than that, there are no other viable candidates for restart.

All three plants face the challenge of hiring and training staff. Unlike the license for a commercial airline pilot or a truck driver, a control room operator’s license is specific to one plant.

The three have something else in common: All are restarting with contracts in hand to sell their output for decades to come.

Palisades, an 805-megawatt pressurized water reactor near Kalamazoo, Michigan, commissioned in 1971, is not precisely what a builder would set out to create today; in fact, Holtec is seeking to build two new reactors there as well, small modular models, each 300 megawatts. But building fresh is slow and expensive, which increases the attraction of reconditioning an old plant.

Dig Deeper

California Toys With Overcoming its Allergy to Nuclear

The Port of Long Beach, seeking to decarbonize and secure a steady supply of energy, has announced a partnership with a startup named Bluecore Energy to explore a 10-megawatt reactor that would be installed on a barge at the port. The company, which has raised $10 million, is headquartered at a warehouse in the port.

Long Beach is the second largest port in the country and wants to double its container volume by 2050, and be carbon-free. Bluecore wants to start with barge-based reactors to supply ports, but later build reactors to power ships.

Dig Deeper

Never Mind the Nuclear Physics; Will It Fit on the Grid?

The Pennsylvania-Jersey-Maryland Interconnection, the country’s largest independent system operator, has removed a 750-megawatt generating project planned by Oklo in Ohio from its interconnection study plan, apparently over concern about whether it could ride through a disruption in voltage.

The project mixes Oklo advanced reactors with gas generation and fuel cells. The fuel cells make direct current, which must be converted to alternating current. PJM has not publicly described the reason for its action, but Oklo says it was told that Oklo had not shown that the generators could handle a disruption. In August 2003 a voltage disruption caused a cascade that created a power failure from Detroit to New York City.

Oklo has complained to the Federal Energy Regulatory Commission that PJM’s action will delay the project by at least 14 months.

Dig Deeper

Tennessee Says It Has Issued Its First Fusion License

Type One Energy, which plans to break ground on a stellarator-type fusion machine this year in Clinton, Tennessee, at the site of an old TVA coal plant, has received a license from the Tennessee Department of Environment and Conservation. Tennessee is an Agreement State, which means it effectively takes over some NRC functions within its borders. This license is a first for the State.

A stellarator is a doughnut-shaped machine that uses magnets to hold a superheated plasma. Type One says the plant will start up in 2034.

Dig Deeper

See You in December?

Tickets are now on sale for the annual Abundance Conference, which will be held this year on December 10 & 11 in Washington, DC. The Abundance coalition is cross-ideological and based on the premise that America can and should build more, including more housing, more energy, more infrastructure, and more opportunity.

The event brings together policymakers, technologists, and builders, and is produced by the Breakthrough Institute and Niskanen Center.

Dig Deeper

Thanks for Reading!

Share Nuclear Notes

Nuclear Notes is produced by the Breakthrough Institute, and covers the policy, regulation, technology, and business of advanced nuclear energy in the United States and beyond.

Every Thursday, we track what’s really going on in the field: the new rules moving through the Nuclear Regulatory Commission, the advanced reactors moving from design to deployment, the companies going public and the utilities merging, and the executive orders and acts of Congress reshaping how the country builds. We explain not just what happened, but why it matters and how the pieces fit together.

Share Nuclear Notes

A Replacement for Yucca?

The Trump administration is circulating draft legislative language that would radically amend the Nuclear Waste Policy Act of 1982. Rather than the government accepting used fuel and burying it at Yucca Mountain, which is still technically the law of the land, the work would shift to the “Nuclear Lifecycle Innovation Campuses.”

In 1987, NWPA amendments designated Yucca Mountain, in Nevada, as the sole location that the DOE could continue to study for a federal repository. The Trump Administration’s draft amendments to the NWPA would allow the DOE to look beyond Yucca to other “willing states” for waste storage and disposal.

The draft language, as reported by Politico, is a follow-up to an announcement in January that the DOE would seek volunteers to host the campuses. Under partnerships between the federal government and the host states, private companies would carry on such activities as reprocessing spent fuel to recover valuable materials, enrich uranium, fabricate new fuel, and possibly operate advanced reactors. They could also dispose of the wastes, although the federal government would retain legal responsibility.

The campuses, according to the DOE, will “advance manufacturing and regional economic growth, enhance national energy security and build a coherent end-to-end nuclear strategy for the country.’’ To realize the Trump Administration’s goal of having 400 gigawatts of nuclear capacity online by 2050, the nation would need hundreds more reactors, and a vastly expanded fuel infrastructure.

With the prospect of thousands of jobs, 28 states have expressed interest in hosting the campuses, according to the DOE. In July, the Department signed memoranda of Understanding with five states, making them the top candidates: Utah, Tennessee, Oklahoma, Louisiana, and Idaho.

Spent nuclear fuel is currently stored in secure pools of water or in dry casks at the places where it was used, a solution that is safe for many decades to come, but creates three prominent problems.

One is financial: Under the 1982 act, utilities were forced to sign contracts with the DOE and pay a fee of one tenth of a cent per kilowatt-hour that their reactors produced, in exchange for a promise from the department to begin picking up the fuel in 1998. When the Yucca program stalled, the utilities sued, and the courts found the government liable for the extra costs of storage, which now run about $800 million a year. A second issue is that the program is so delayed that some of the fuel is now sitting in locations where the reactor has been retired, decommissioned, and demolished, but the dry casks still require inspection and security. And the third is that it is a talking point for nuclear opponents who would like to block new reactors.

The draft legislation would make it the policy of the United States to reprocess spent nuclear fuel, to the extent practical, through the private sector. The energy potential of the used fuel had been written off under the 1982 law because President Gerald Ford decided that the United States would be setting a bad example by recovering materials from the fuel, which is one route to nuclear proliferation. President Jimmy Carter, who followed him, took the same position. Reagan then changed the policy, but not the practice. Now, the Trump administration would like the country to start reprocessing, partly because advanced reactors can readily use the plutonium as fuel.

As added inducement, the draft bill would make the Nuclear Waste Fund available for use and reinstate a fee on nuclear generators. Payments by the utilities were halted in 2014 in a court case brought by the Nuclear Energy Institute, the industry’s main trade association, which argued that if the fee was meant to fund the development of Yucca, and the Obama administration had frozen the work there, utilities should not have to pay. With the money paid in thus far, plus accrued interest, the Fund is approaching $50 billion.

Dr. Adam Stein, the Director of Nuclear Energy Innovation at the Breakthrough Institute, pointed out that in addition to reserving the money for Yucca, current law also prevents the government from evaluating any other site. “Parts of this bill are simply necessary,” he said.

The draft bill maintains federal authority, stating that “Nothing in this Act shall affect the responsibility of the Federal Government to provide for the disposal of spent nuclear fuel and high-level radioactive waste resulting from either governmental or private sector activities”, and that the DOE “shall give priority to facilities and activities located at the Nuclear Lifecycle Innovation Campus in carrying out this responsibility.”

Some experts are calling out that selecting five potential hosts for the fuel cycle campuses is only a preliminary step. “Five signed memoranda are not five host communities,” wrote Vincent Ialenti, who formerly worked at the Department of Energy managing the “Consent-Based Siting Consortia,” an effort under which twelve teams around the country sat down with communities that could host a repository to talk about the costs and benefits.

Ialenti, writing in an opinion column in The Hill, said that “No final host agreement has been signed, no construction funds awarded and the states have agreed only to continue negotiations. That is a real beginning, but it is not a victory. Treating it as one risks repeating the cycle of overpromising and disappointment that has paralyzed American nuclear waste policy for four decades.”

Dig Deeper

An Ambitious Fusion Groundbreaking

California-based start-up Pacific Fusion has broken ground in New Mexico on a fusion demonstration that it says will cost $1 billion and be running by 2030. If successful, the plant would still be far short of a commercial model, but it would achieve a first, releasing more energy from fusion than it takes to power the plant.

Lawrence Livermore National Lab made headlines in 2022 by using a fusion machine, originally built for weapons research, to make as much energy as was applied to the fuel. But it did not actually create energy overall. Lawrence Livermore counted the energy of the lasers used to squeeze the fuel, but not the energy needed to make the laser beams, which was considerably larger.

Pacific Fusion has a different concept, using electric current to make a magnetic field. The field compresses and heats the fuel to the extreme temperatures required for fusion. The company says its hardware and materials are less expensive and consume less energy. If that approach works, the company will still need to solve the challenge of repeating the procedure promptly without having to wait for the equipment to cool, among other problems.

The Albuquerque apparatus will be able to create several fusion events per day, the chief technical officer told TechCrunch. Lawrence Livermore created about one event per day. But a commercial plant would need to do that much more often, perhaps once per second.

Whatever the technical challenges, the investors seem convinced. The company, founded in 2023, has raised more than $1 billion, led by a venture capital firm, General Catalyst, that has invested in a variety of companies involved in power production and transmission. The funds are released as the company reaches technical milestones.

According to the Fusion Industry Association, total investments in the field have reached over $14 billion.

Dig Deeper

It’s Official: Nuclear Energy Is an Element of National Security

The Trump administration has listed nuclear energy as part of its National Security Science and Technology Strategy, and told federal agencies to prioritize its use as one of several “key enabling technologies.”

Among other steps, it calls for facilitating partnerships between community colleges and other educational institutions to develop a workforce to build and operate reactors. It also calls for public/private partnerships to advance nuclear technology, both fission and fusion, and for microgrids using advanced reactors.

Dig Deeper

The Army Drafts Five Reactors

The U.S. Army has chosen five sites for micro-reactors, and five suppliers to each deliver one, with the first scheduled to be in service by September 2028. It expects to spend $2.2 billion.

“Everything that we do—from communications to radar—requires constant energy,” said Dr. Jeff Waksman, Principal Deputy Assistant Secretary of the Army for Installations, Energy and Environment, in a statement. “And when you think about where things are going in the future with drones and energy weapons, there’s just more demand for electricity.”

The Army also has a program to demonstrate a transportable reactor. The five proposed reactors in the recently-announced program are intended to operate in a single spot for years.

The Army appears to be hedging its bets, with a variety of suppliers and reactor models, all first-of-a-kind. The cohort includes three companies with extensive nuclear experience and two start-ups.

Westinghouse will install a reactor at Fort Drum, in New York, although it will not resemble the big Westinghouse reactors that have been operating on the grid for decades. BWX Technologies, which builds reactor cores for the Navy, will build a reactor at Fort Campbell, Kentucky. General Atomics, which has built dozens of research reactors, will build a microreactor at Fort Hood, Texas. The two start-ups are Antares Nuclear, at Fort Bragg, North Carolina, and Radiant Industries, at Fort Benning, Georgia.

Dig Deeper

Six and Counting

Westinghouse’s eVinci microreactor has achieved initial criticality, the sixth model to do so this year, at the Nevada National Security Site.

Westinghouse is not a start-up; its pressurized water design dominates the industry. But eVinci uses TRISO fuel, particles of fissile material wrapped in concentric layers of heat-resistant materials. The reactor has “a compact architecture designed to provide resilient energy in remote and challenging environments, such as defense applications and space,” the company said. It is meant to go eight years without refueling.

The Canadian province of Saskatchewan is providing $59 million for a demonstration of the technology, which is well-suited for remote communities in the far north. Other entities are pursuing use of the reactor in ships and on the moon.

Dig Deeper

At TMI, an Expensive U-Turn Nears Completion

A specially built transformer, weighing half a million pounds, has arrived from South Korea at the Three Mile Island Unit 1 reactor, a key step in restarting the plant, which is now called the Crane Clean Energy Center.

Constellation shut the plant in 2019, because of low electricity prices and to cut expenses. In 2024 Microsoft signed a 20 year contract with Constellation to restart the plant, reportedly at an above-market price.

In decommissioning, Constellation drained the oil out of the old transformer and then destroyed it. The new transformer is one of three that the plant will need, and it cost nearly $10 million, shipping not included. The total cost of the re-start is about $1.6 billion.

Re-start was originally scheduled for 2028, but with the opportunity for revenue from a strong electricity market, the company hopes to have it in service next year.

Dig Deeper

Thanks for reading!

Share Nuclear Notes

Nuclear Notes is produced by the Breakthrough Institute, and covers the policy, regulation, technology, and business of advanced nuclear energy in the United States and beyond.

Every Thursday, we track what’s really going on in the field: the new rules moving through the Nuclear Regulatory Commission, the advanced reactors moving from design to deployment, the companies going public and the utilities merging, and the executive orders and acts of Congress reshaping how the country builds. We explain not just what happened, but why it matters and how the pieces fit together.

Share Nuclear Notes

Nuclear in California Gets a Warm Embrace and a Cold Shoulder

Diablo Canyon, the last surviving nuclear plant in California, lives on a short leash, held by a fickle legislature in Sacramento. But Pacific Gas & Electric, the plant’s owner, got a federal payment of $271 million from the Department of Energy’s Civil Nuclear Credit Program, which was established four years ago as a way to help reactors survive a crash in wholesale electricity prices, brought on by cheap natural gas.

The payment was for Unit 1; Unit 2 will become eligible soon and the plant could get up to $1.1 billion. PG&E will use the money to pay back part of a loan made by California’s Department of Water Resources, to help get the plant ready for extended operation. PG&E had ceased making investments in Diablo Canyon when California insisted that it be shut, but faced big expenses after the state reversed course when the political leadership realized that the reactors were essential to meeting the state’s carbon dioxide goal and meeting its electricity supply requirements.

The plant generates about 18 million megawatt-hours of carbon-free electricity each year, about 9% of the state’s energy consumption. California’s problem is not just replacing that 9%; it’s that the state’s Energy Commission is predicting a 50 percent rise in demand by 2045, driven by data centers, electric vehicles, and other needs.

The NRC gave the Diablo Canyon reactors a 20-year license extension in April, through 2044 and 2045, which would mark 60 years of operations. But the California Legislature needs to approve any extension of operations at Diablo Canyon that goes beyond 2030. Governor Gavin Newsom recently declined to support the extension, saying that was a decision for the next governor. More to the point, it was probably not a decision for a politician who is likely to seek the Democratic nomination for President.

A coalition of nearly 50 groups recently emerged to press the legislature to extend Diablo Canyon’s operations. The groups include the San Luis Obispo County Board of Supervisors, chambers of commerce, agricultural organizations, taxpayer groups, and others. Nearly 100 elected officials, including mayors and city council members, also signed.

“California must not take a step backwards on our climate goals and rely on fossil fuels to backfill energy needs,” said one supporter in a statement published by the group. Natural gas would be the likely replacement for the plant’s output.

Public sentiment toward nuclear energy in California has an interesting history. California is the only state where a reactor was closed by referendum. The Sacramento Municipal Utility District closed its Rancho Seco reactor in 1989. The San Onofre Nuclear Generating Station was closed after the owners botched the replacement of its steam generators. California also maintains its moratorium on building new nuclear. This unfriendly approach to nuclear is in sharp contrast to the state’s pioneering commitment to carbon-free energy. But opponents, who had once celebrated an agreement to close Diablo in 2025, are fighting on. Some of them assert that Diablo Canyon is the cause of massive mid-day electricity surpluses, because it does not reduce its output to accommodate the flood of solar energy.

The ongoing political conflict puts California out of step with a national turn of opinion towards nuclear energy. The Los Angeles Times recently reported that at a public meeting in San Luis Obispo County, where the plant is located, half the public comments favored the plant’s continued operation and half were opposed. Nationally, one recent poll found that 77 percent favor nuclear energy.

Ironically, California is also an incubator of advanced nuclear. Companies there have raised billions of dollars. Oklo, which has ambitious plans for a fleet of small fast-neutron reactors, is a Silicon Valley start-up, based in Santa Clara. Valar Atomics, which recently achieved an initial criticality with a high-temperature gas reactor, is based in El Segundo. Kairos Power, which is building a series of high-temperature test reactors using TRISO fuel in a salt bath, is headquartered in Alameda. General Atomics, designer of the TRIGA reactor used on university campuses around the world, and now deeply involved in micro-reactors, is in San Diego. Deep Fission, which is designing a narrow pressurized water reactor that can fit in a deep well, and use the earth as containment, is in Berkeley. Antares Nuclear, which is targeting military deployment, is in Torrance.

Dig Deeper

Why Nuclear Projects Are Complicated

One of the reasons that building a nuclear plant can be slow and cumbersome is that so many different parties have a stake in the project, and their goals are not completely parallel. A new report by Dr. Adam Stein, the Director of Nuclear Energy Innovation at the Breakthrough Institute, dissects this “stakeholder stratification” problem.

Dr. Stein recently testified before the Senate Environment and Public Works Subcommittee on Clean Air, Climate, and Nuclear Innovation and Safety, saying “Nuclear projects are often discussed as if one constraint determines success. Sometimes the constraint is said to be the NRC. Sometimes it is financing. Sometimes it is public acceptance, supply chain capacity, or fuel availability.”

But focusing on one cause gives an incomplete picture, because a project has to satisfy multiple parties: the NRC (for safety); the buyer (for revenue projections); investors (for construction risk); state and local governments (for public needs and benefits); grid operators (for how it will fit into the electricity system); host communities, which must trust the project; supply chains, which have to deliver; and other stakeholders who serve distinct functions.

Not only is decision-making distributed, but a successful project has to satisfy all of these constituencies simultaneously. Measures that may decrease risk for one party can increase it for another. And the consensus must persist for the duration of the project, which can be substantial.

“Regulators, investors, utilities, grid operators, policymakers, and communities each evaluate the project using different criteria, under different constraints, and with different consequences for failure,” he testified. “These evaluations are not reducible to a common metric and do not converge through centralized authority, resulting in a system in which decisions are distributed, interdependent, and only indirectly coordinated. The result is a persistent pattern in policy and project design: interventions are routinely applied at the wrong level of the system.”

The report offers a structural framework for a more realistic analysis of the hurdles. Understanding the system is where effective analysis begins.

Dig Deeper

Three Nuclear Organizations Approve an AI Virtual Assistant

Atomic Canyon, an artificial intelligence company, has developed a tool for use in reactors that has been approved by three nuclear industry organizations: the Institute for Nuclear Power Operations, an industry group established to share information and skills after the Three Mile Island accident; the Electric Power Research Institute, a non-profit utility consortium; and the Nuclear Energy Institute, the industry’s largest trade organization.

Atomic Canyon says its tool was “built specifically to understand the language, workflows, and knowledge environments of nuclear power.” And the tool is intended to let users “ask questions in plain language and receive responses grounded in industry content,” and improve access to industry operating experience.

Constellation Energy, which operates 26 reactors across six states, has already adopted it.

Dig Deeper

Like Large-Format Lego Blocks, for Nuclear

One of the reasons that nuclear construction is so expensive is the cost of nuclear-grade concrete. Kairos Power thinks it has a better approach: large, precast concrete structures that can be factory-built and promptly installed. It is using that approach at a test reactor in Tennessee.

Kairos has signed a memorandum of understanding with Oak Ridge National Laboratory, the University of Tennessee-Knoxville, and several other entities, to explore wider deployment of that technology, as well as other advanced technologies such as electron-beam welding and additive manufacturing (an industry term for large-scale 3D printing), which would be used to create the forms used to make precast concrete parts.

Dig Deeper

An Advanced Reactor Pilot Anticipates Another $1 Billion

J. Clay Sell, the Chief Executive Officer of X-energy, said in an earnings call that his company expects to receive another $1 billion from the Department of Energy through the Advanced Reactor Demonstration Program. X-energy is developing a high-temperature gas reactor in Seadrift, Texas, under the ARDP. X-energy has to match the grant, dollar for dollar, but the company recently raised $1.1 billion from an initial public offering.

Sell also said that the company had entered into a long-term agreement with two suppliers, Centrus Energy and General Matter, for uranium enriched to nearly 20 percent, and with another supplier to provide the nuclear-grade graphite it will need.

Dig Deeper

Thanks for reading!

Share Nuclear Notes

Nuclear Notes is produced by the Breakthrough Institute, and covers the policy, regulation, technology, and business of advanced nuclear energy in the United States and beyond.

Every Thursday, we track what’s really going on in the field: the new rules moving through the Nuclear Regulatory Commission, the advanced reactors moving from design to deployment, the companies going public and the utilities merging, and the executive orders and acts of Congress reshaping how the country builds. We explain not just what happened, but why it matters and how the pieces fit together.

Share Nuclear Notes

And Then There Were Five

A fifth reactor has reached initial criticality under a rush program at the Department of Energy, induced by promising projections for energy demand, an encouraging federal government, and a rush of private money into start-ups with new engineering ideas.

“Initial criticality,” sometimes referred to as zero-power testing, means that the core achieved sustained, controlled fission, although at a power level measured in kilowatts of heat, not megawatts of electricity. It is useful in validating a design and providing performance data needed for licensing.

The most recent criticality was at Oklo’s Groves reactor, which is not intended to produce energy, but instead manufacture isotopes. It is unpressurized, with the fuel sitting at the bottom of a deep pool of water that provides shielding and moderates the speed of the neutrons released during fission, so that they are more likely to transmute target atoms.

Oklo says that the various steps involved in bringing the reactor to initial criticality, including selecting vendors and building a safety case, are a good rehearsal for its main goal of building small power reactors. “Reaching criticality in less than a year is an incredible milestone for our team,” said Jacob DeWitte, co-founder and CEO of Oklo, in a statement. Groves is the first step in building isotope producers that will make materials useful in cancer treatment, manufacturing, space exploration, and other scientific research. The U.S. is not self-sufficient in isotopes.

“Groves demonstrates that the domestic nuclear industry can once again move from design through construction, authorization, and startup on timelines that are measured in months rather than years when developers, suppliers, and regulators work together on an integrated deployment approach,” the company said.

The most common type of pool reactor in the United States is the TRIGA research reactor, which is a staple of university nuclear engineering departments. TRIGAs are regulated by the NRC. They usually take years to build and license, even though they only operate in pulses, not continuously. The Groves reactor, in contrast, was built under the Department of Energy’s Reactor Pilot Program (RPP).

The RPP, which was created in response to Executive Order 14301, announced a year ago that it had selected 11 advanced reactor projects, with a goal of having at least three reach initial criticality by July 4, 2026. Four ended up doing so.

Antares Nuclear’s Mark-0 reached initial criticality on June 4, the first to do so under the program. It is a microreactor design, with heat pipes that bring heat energy from the core for direct conversion into electricity. It uses high-assay low-enriched uranium (HALEU) fuel in tri-structural isotropic form. The U.S. military is a likely customer.

Valar Atomics’ Ward 250 reactor followed soon after. It also uses tri-structural isotropic fuel but is cooled by helium. It was built under the RPP at the Utah San Rafael Energy Lab rather than at a national laboratory–the first DOE authorized reactor to do so. Its commercial product is intended to produce 100 to 250 kilowatts, and to be transportable, meaning that it can be shut down and left to cool for a few days, and then moved.

Deployable Energy’s Unity Nuclear Battery demonstration reactor came next, a one-megawatt transportable microreactor running on low-enriched uranium, with a helium coolant. The reactor uses “non-exotic materials and processes,” the company says. It is intended as a replacement for diesel generators, among other uses, and will run for five years without refueling.

And just meeting the July 4 deadline, Aalo Atomics started up a sodium-cooled reactor at the Idaho National Laboratory. Aalo had broken ground on the project just after the program announcement eight months earlier. “The hardest problem in nuclear was never the physics, our country simply forgot how to build,” Yasir Arafat, the president and chief technical officer, told World Nuclear News. The core is capable of making enough heat to produce 10 megawatts of electricity, the company said, and the reactor is designed to be deployed in clusters of five. Aalo’s intention is to mass-produce the reactors on an assembly line, for data centers. It says it will begin supplying commercial electricity next year.

Five criticalities in only a few months has little precedent in this country. During the wave of construction that produced the current nuclear fleet, the banner year of 1974, 14 reactors got low-power licenses. The comparison is not perfect because those were full-scale reactors rated in the hundreds or thousands of megawatts, while the initial criticalities being recorded now are mostly in the category of lab experiments, although they are useful steps for commercial reactors. And they are of radically different designs.

These pilot reactors, Groves included, are remarkable for having reached initial criticality in less than a year since groundbreaking. The initial demonstration still leaves these developers with huge tasks, like equipment to convert heat to electricity, among others.

Dig Deeper

Enjoy Your Summer Break, Congress

The House and Senate have gone home for the summer, but will return for about three weeks of work in September, and a few days in October. Congress has a lot of work on its plate, some of it nuclear. On the nuclear front, Congress has multiple topics on its plate with bipartisan support spanning licensing, financing, tax credits, and more.

Before recess, the House Energy and Commerce Committee’s Subcommittee on Energy approved six nuclear bills that would revise NRC licensing and DOE nuclear reporting, forwarding them to the full committee: H.R. 3978, Nuclear REFUEL (Recycling Efficient Fuels Utilizing Expedited Licensing) Act; H.R. 9612, American Enrichment Deployment Act; H.R. 5549, Efficient Nuclear Licensing Hearings Act; H.R. 9613, Nuclear Advisory Committee Reform Act; H.R. 9614, NRC Staff Pay Alignment Act; and H.R. 9084, Department of Energy Nuclear Transparency Act.

In April, also in the House, the Nuclear Rate Stabilization Act was introduced to modify tax rules for nuclear projects, allowing projects to opt out of the Investment Tax Credit normalization rule. This could have direct effects in lowering consumer rates in the near term instead of stretching tax credits over 40 years.

On the Senate side, there are multiple bills as well. Right before recess, Senators Kelly and Lummis introduced the Modernizing Outdated Regulations to Expand (MORE) American Fuel Act, the Senate companion to the American Enrichment Deployment Act. It would let applicants start building uranium enrichment plants before the NRC issues an operating license. The NRC would still have licensing authority, and the plant would still have to go through environmental review.

Building more enrichment capacity is important because the complete ban on using enrichment services from Russia takes effect in 2028, and demand for higher enrichment is growing because many advanced reactors require HALEU fuel.

The Foundational Infrastructure for Responsible Use of Small Modular Reactor Technology (FIRST) Act, introduced by Senators Budd and Coons, would codify the State Department’s existing FIRST program. The State Department calls FIRST a “capacity-building program,” that allows countries with rapidly-growing energy demand move into the nuclear field with “the highest international standards for nuclear safety, security, and nonproliferation.” It is also a strategy for favoring American reactors over those from Russia or China.

In May, Senators Lummis and Kelly introduced the Build Nuclear with Local Materials Act. It would require the NRC to allow the use of commercial-grade steel and concrete in structures that are not safety-related.

And there is more on deck. Policy conversations on nuclear financing will likely continue this fall. Congress may revisit conversations about nuclear waste policy, on items like the nuclear waste fund, moving away from Yucca Mountain, and revising the Nuclear Waste Policy Act, which could begin as soon as this fall. Similar proposals were made as recently as last year. Tackling nuclear waste policy questions are essential to making the Trump Administration’s ambitions on the Nuclear Lifecycle Innovation Campuses achievable.

It is not clear how much Congress will accomplish before November elections, or in the “lame duck” session that will follow, when many legislators know they will not be returning to Capitol Hill. But having a bill make some progress in this session may give it a head-start when re-introduced in the next session.

Dig Deeper

Governor of California Punts on Nuclear

Gavin Newsom, who is preparing to run for president, said last week in response to a question about continued operation of the Diablo Canyon nuclear plant that he would not work to extend operations beyond 2030. Newsom and the legislature had sought to block the plant’s license renewal but then reversed course when it became obvious that California needed the electricity. There is still considerable opposition to nuclear energy in the state.

A decision beyond 2030 “will be the baton I pass on to the next administration,” he said. Nationally, opposition to Diablo would win Newsom the support of some Democrats and the enmity of others.

In April, Governor Newsom said he welcomed the NRC’s approval of license extensions for the twin reactors.

Dig Deeper

Get Ready for Abundance

The yearly convening of policymakers, technologists, and builders will be held on December 10 & 11 in Washington, DC, and tickets go on sale on August 18th. The Abundance coalition is cross-ideological and based on the premise that America can and should build more, including more housing, more energy, more infrastructure, and more opportunity.

The event is produced by the Breakthrough Institute and the Niskanen Center.

Dig Deeper

Correction: Last week this newsletter misidentified the Gulf of Mexico Research Initiative as the company that is providing SuperCritical Materials with an oil platform to test its system for harvesting uranium from seawater. It is the Gulf Offshore Research Institute.

Thanks for reading!

Share Nuclear Notes

Nuclear Notes is produced by the Breakthrough Institute, and covers the policy, regulation, technology, and business of advanced nuclear energy in the United States and beyond.

Every Thursday, we track what’s really going on in the field: the new rules moving through the Nuclear Regulatory Commission, the advanced reactors moving from design to deployment, the companies going public and the utilities merging, and the executive orders and acts of Congress reshaping how the country builds. We explain not just what happened, but why it matters and how the pieces fit together.

Share Nuclear Notes

A Nuclear Company Goes Public, and It’s Not a Startup

Westinghouse, which has been privately held since 2018, wants to go public again. This would be different from the other initial public offerings in the nuclear field, because Westinghouse is a major presence in the business of fueling and maintaining the current fleet.

Westinghouse’s corporate history is an odyssey worthy of a Hollywood epic. It was founded in 1886 by a Civil War veteran, George Westinghouse, whose first major invention was a braking system controlled by compressed air that revolutionized rail safety. By the late 1880s he had moved into the electricity field. His company was a competitor to Thomas Edison’s.

In 1957, the company supplied the first commercial pressurized water reactor, an upscaled version of a submarine propulsion reactor. In the 1900s Westinghouse went into everything from elevators to mortgage lending to appliance manufacturing. It bought the CBS television network, renamed itself after the company it had acquired, and spun off its nuclear business. It sold the nuclear portion to British Nuclear Fuels Ltd. (BNFL) in 1999, for $1.1 billion. BNFL sold it to Toshiba in 2006 for $5.4 billion.

But Westinghouse went bankrupt trying to finish the Vogtle reactors in Georgia, which it offered at a fixed price. It was bought by a Canadian turn-around firm, Brookfield Asset Management, for $4.6 billion. Brookfield sold a minority stake to another Canadian company, Cameco, a uranium miner.

In October 2025, Brookfield and Cameco announced a partnership with the United States government, with Washington promising to procure $80 billion from Japan to finance new reactors. If Westinghouse and the Energy Department hit certain milestones, the U.S. Treasury could end up with 20 percent of the stock.

The company has a lucrative business servicing Westinghouse reactors around the world, supplying fuel, performing upgrades, and doing specialized maintenance work. It is developing a microreactor called eVinci, and trying to sell more copies of its big reactor, the AP1000, in the United States, Eastern Europe, the Middle East, and Asia. The on-again, off-again deal between the Trump administration and Saudi Arabia would be for AP1000s.

If a significant number of AP1000 reactors are ordered for export, or if the Trump administration meets its goal of having ten big reactors under construction in this country by 2030, Westinghouse would need significant additional capital just to meet the role of a seller of nuclear steam supply systems, which is the role it played when the current fleet was built. At Vogtle it took on a bigger role of actually managing construction, which it might do again.

Several nuclear start-ups have gone public, but they would be dwarfed by Westinghouse. And all of those businesses are based on technologies that have not been commercialized yet, in contrast to the AP1000, a commercially deployed design with two operating units at Vogtle and four in China.

The AP1000 is in a class referred to as “generation III+,” meaning that it is similar in broad outline to reactors now running, being water-moderated and water-cooled. But it is optimized to use passive forces in an accident (AP stands for Advanced Passive).

Because it is not so radical a departure from today’s pressurized water reactors, it may be more attractive to some companies that already operate reactors. And while it is clearly not a small modular reactor, Westinghouse says it is “modularized,” meaning that major components can be built in a shipyard or other factory and shipped to the site.

That turned out to be a major flaw at Vogtle, because the shipyard picked to supply the modules had difficulty meeting the schedule and NRC-mandated quality control requirements.

Westinghouse also has an SMR design, the AP300, which uses many of the same components as the AP1000. Potential developers have not publicly expressed much interest in the AP300. But Westinghouse has announced agreements with Amentum, an engineering firm, to support deployment of both AP models.

Terms of Westinghouse’s initial public offering have not been disclosed, so the proposed valuation and the debt structure are not clear. Neither is the timing, which could depend on market conditions and regulatory approvals.

Dig Deeper

A New Try at Harvesting Uranium from Seawater…

The oceans hold 4.5 billion metric tons of uranium, equal to many thousands of years of consumption. But the uranium is at a concentration of only about 3.3 parts per billion.

A start-up in Austin, Texas, SuperCritical Materials, is preparing to demonstrate a new technology that will concentrate the uranium by a factor of more than 1 million, to 4,000 parts per million. That would still need additional processing, but compares favorably to uranium ore taken from on-shore mines. “That’s pretty darn good in the uranium mining world,” said Canon Bryan, the company president and chief executive.

The company has a fiber that preferentially adsorbs uranium molecules. “Adsorption” means making materials stick to a surface, like flies on fly paper, as opposed to “absorption,” when the material is chemically incorporated. It spreads one gram of the material on 7 square kilometers of acrylic fibers. The fibers are immersed in seawater for three weeks and then pulled out, and the uranium, in a carbonate form, is stripped off for processing.

The company says it has raised $4.5 million privately. And it anticipates receiving more money through a $20 million grant that BP made to a nonprofit, the Gulf Offshore Research Initiative (GORI), following BP’s 2010 oil spill in the Gulf. GORI is also giving SuperCritical access to a defunct oil drilling platform.

SuperCritical is planning an initial public offering of stock, but it has also attracted an investment from Neal Froneman, who has led several conventional on-shore uranium mining companies. Froneman has also become chairman of the board.

According to Bryan, the technology can produce uranium at a cost competitive with today’s spot price. But SuperCritical won’t complete a full-scale demonstration until next year.

China has experimented with recovery from the sea, as has the Woods Hole Oceanographic Institution, with the Pacific Northwest and Oak Ridge National Labs.

If any of the technologies work, the supply is nearly inexhaustible, because as the concentration of uranium in seawater is lowered, more leaches into the water from subsea rocks.

Dig Deeper

…And Enriching Uranium for Reactor Fuel

Two U.S. Senators have proposed legislation to rationalize regulation of new enrichment plants. Mark Kelly, a Democrat from Arizona, and Cynthia Lummis, a Republican from Wyoming, have introduced the Modernizing Outdated Regulations to Expand American Fuel Act, which, among other changes, would let builders start on new enrichment plants before they have an operating license in hand.

The Breakthrough Institute supports the changes. “The United States lacks the domestic uranium enrichment capacity needed to support significant growth in nuclear energy,” said Dr. Adam Stein, Director of Nuclear Energy Innovation at Breakthrough. “Expanding that capacity is essential to enabling American nuclear deployment and strengthening energy security.”

“This approach allows construction and licensing to proceed in parallel without prejudging or limiting the NRC’s final licensing decision. The bill appropriately preserves the NRC’s full authority over the operating license while maintaining public participation and advance notice for surrounding communities,” he said.

Dig Deeper

Another Initial Criticality

Another microreactor has reached criticality, this one designed by Los Alamos National Laboratory. The ZiaCore reactor used low-enriched uranium in a ceramic form with a very high melting point. It is moderated with a zirconium hydride material.

It was designed to accommodate higher enrichments when that type of fuel is more readily available.

Los Alamos said that the reactor was brought to criticality in April and May, before the rush of private-sector designs that were struggling to beat President Trump’s July 4 deadline. The purpose of this criticality, like the ones produced by start-up companies, was to validate the core design, part of a long process toward commercialization.

Dig Deeper

A Nuclear Startup Chooses an Old-School Route to Safety

TerraPower, which is developing a plant in Wyoming that marries a high-temperature fast reactor to a heat battery, has joined the Institute of Nuclear Power Operations (INPO), a low-profile organization that is hugely influential within the industry. INPO was founded after the Three Mile Island accident in 1979 and sends audit teams to monitor operations, in a peer-to-peer process that industry observers say is more intensive than the NRC’s.

INPO was formed decades ago with the belief that a nuclear accident anywhere was very bad news for all the companies in the industry, worldwide.

TerraPower is the first advanced reactor company to join INPO.

Dig Deeper

A Nuclear Site Could Get a New Tenant

Fossil fuel and renewable plant developers often “re-power” their sites, tearing out old equipment and replacing it with something more modern. Now Holtec, which decommissions old reactors, may do the same at the Oyster Creek Generating Station in New Jersey.

The site used to host a 636-megawatt boiling water model, and was a milestone in the industry because GE offered it as a turnkey project, to get the technology rolling. It operated from 1969 to 2018.

Holtec is developing a 300-megawatt small modular reactor design and is now proposing to put four of them at the Oyster Creek.

Dig Deeper

Thanks for reading!

Share Nuclear Notes

Nuclear Notes is produced by the Breakthrough Institute, and covers the policy, regulation, technology, and business of advanced nuclear energy in the United States and beyond.

Every Thursday, we track what’s really going on in the field: the new rules moving through the Nuclear Regulatory Commission, the advanced reactors moving from design to deployment, the companies going public and the utilities merging, and the executive orders and acts of Congress reshaping how the country builds. We explain not just what happened, but why it matters and how the pieces fit together.

Share Nuclear Notes

Giving Nuclear Waste Another Chance

The Energy Department has announced that it has selected five states as potential hosts for “Nuclear Lifecycle Innovation Campuses.’’

Utah, Tennessee, Oklahoma, Louisiana and Idaho will “continue exploring opportunities,” according to the announcement, which says that the campuses will “support activities across the full nuclear fuel cycle, including fuel fabrication, enrichment, reprocessing used nuclear fuel, and final disposition of nuclear fuel.” It could also include new reactors.

Waste disposition has been part of the deal since the initial Request for Information earlier this year. Tennessee and Utah said they would consider burial. Idaho said it was open to “long-term monitored storage.” Oklahoma and Louisiana did not make their proposals public.

The department got 28 applications from 26 states, and describes these five as “initial contenders.” Governors of the five states gave effusive tributes to the fuel hub idea.

The Trump Administration is not looking only for a burial site, but for a major industrial complex, pairing what has been seen as a burden with economic and development incentives. One of those incentives is the opportunity to “reprocess” spent nuclear fuel, which would separate unused uranium and usable plutonium generated in reactor operation, and fabricate them into new fuel.

Reprocessing has been a sticky subject and was shunned by the Ford and Carter administrations, because it can be used to purify materials that can be used in nuclear weapons. The theory was that reprocessing here would set a poor example for other countries. Reprocessing is also expensive. But it recovers valuable unused fuel, shrinks high-level radioactive waste volumes, and yields useful industrial isotopes.

The Trump administration has embraced the idea, and suggested that the job should be undertaken by the private sector. “These campuses will be massive generators of economic growth, create thousands of high-paying jobs, and be crucial to unleashing America’s nuclear renaissance,” Energy Secretary Chris Wright said in a statement. By the Energy Department’s estimate, a fuel cycle campus could draw in $50 billion in capital investment, and generate billions in tax revenue and nearly 25,000 jobs.

Establishment of a reprocessing system, and a repository for the material that can’t be recovered for re-use, would resolve a frequent question from nuclear opponents: “What about the waste?” Use of plutonium-239 would also reduce the amount of uranium that must be enriched to produce reactor fuel.

The companies that operate today’s nuclear reactors have not shown much enthusiasm for reprocessed fuel, because using virgin uranium is cheaper and simpler. However, many light-water reactors in Europe run on such fuel, and some advanced reactors now under development could also use that fuel. Reprocessing would also reduce the amount of material that the federal government pays to store. So far the government has paid over $11 billion, and now pays about $800 million per year, because it promised to begin taking the waste in 1998, in exchange for collecting a fee from the utilities for each kilowatt-hour generated by reactors.

A court suspended the fee because the Yucca program fell apart. Including interest, the Nuclear Waste Fund has a balance in excess of $47 billion.

Among the challenges is that currently, Federal law says that the Energy Department will build a repository. Only one U.S. nuclear plant, Palo Verde in Arizona, was designed to use fuel with reprocessed plutonium, and several TVA reactors have been evaluated for that purpose. Many light-water reactors in Europe run on such fuel, and some advanced reactors now under development could also use that fuel.

Notably absent from the list is Nevada, which was selected by Congress in 1987 as America’s waste repository site. That effort died when Harry Reid of Nevada became the Senate Majority Leader and cut off funding. And when then-Senator Barack Obama of Illinois ran in the Democratic Nevada Primary for president, he promised not to pursue the site. So the location chosen by Congress, Yucca Mountain, is still the law of the land and the only legal site, but is politically unviable.

For any other geologic repository site to move forward, the Nuclear Waste Policy Act is going to have to be amended. That amendment, debates over reprocessing, and the Nuclear Waste Fund are still points of contention that will need to be resolved in order to enable the Nuclear Lifecycle Innovation Campuses.

Dig Deeper

Oklo Inches Forward Toward Licensing

Oklo, which wants to build and operate small reactors around the country, is technically still in the pre-application phase of licensing with the NRC for its 75 MWe Aurora Powerhouse, but reports progress on a few avenues.

Last week, Oklo received DOE authorization for one of its other business plans, the Groves isotope-producing pilot reactor in Texas.

The Groves reactor has a maximum power level of 100 watts of heat energy. It does not make electricity. It is being built under the Department of Energy’s Reactor Pilot Program, not licensed by the NRC. It is on private land, about 30 miles south of Austin. The commercial design is planned to be 15 megawatts thermal, or a million and a half times larger. The start-up authorization allows Oklo to load fuel, test, and operate the reactor.

According to Oklo, the project “demonstrates nearly every element of a commercially oriented deployment model that Oklo can repeat and scale across future projects.” That includes construction, sourcing the fuel, and manufacturing or purchasing all the components, and training the operators. “Future Oklo projects will build on the established systems, qualified suppliers, and approved operating programs established through Groves,” the company said.

In addition, Oklo is building its Aurora reactor at the Idaho National Laboratory under DOE’s Reactor Pilot Program. In contrast to other reactor projects at the Idaho National Laboratory, the company’s plan is to construct and operate its FOAK pilot reactor under Energy Department rules, but later to get the plant approved by the NRC so it can sell electricity commercially. With DOE authorization “we can get to construction much quicker,” said Bonita Chester, head of communications. Oklo is consulting with the NRC along the way, she said, but it is building under DOE approval which is faster and easier to get. Oklo’s Quality Assurance program for the Aurora has already been accepted for review by the NRC.

The company’s work with NRC amounts to a do-over. In March 2020, Oklo submitted an application to build a power reactor. But in January 2022, the NRC rejected the application due to “significant information gaps in its description of Aurora’s potential accidents as well as its classification of safety systems and components.”

The NRC dismissed the application “without prejudice,” meaning that it could be re-filed.

Dig Deeper

Bill Proposes to Codify State Department Effort to Promote Advanced Nuclear Energy Abroad

The Foundational Infrastructure for Responsible Use of Small Modular Reactor Technology (FIRST) program was set up in 2021. Senators Chris Coons, Democrat of Delaware, and Ted Budd, Republican of North Carolina, are seeking to heighten nuclear cooperation and U.S. exports by codifying the program into statute.

This State Department effort began during the Biden administration to help non-nuclear countries develop their capacity to regulate and build small modular reactors.

The Breakthrough Institute is among the nuclear advocates endorsing the bill. “Strengthening U.S. leadership in nuclear energy deployment abroad and supporting the safe, secure expansion of nuclear power globally are a natural extension of the American nuclear industry’s growth, and should be prioritized for energy security, clean energy goals, and national security alike,” said Adam Stein, Director of Nuclear Energy Innovation at the Breakthrough Institute. The bill would codify FIRST “as an instrument of commercial statecraft,” he said.

Dig Deeper

Trump Administration Considers Offshore Reactors

The NRC and the Marine Minerals Administration, which administers the Outer Continental Shelf, have signed a memorandum of understanding to coordinate their activities if an applicant wants to build a reactor offshore. One possibility is reactors on the sea floor, although neither those nor floating reactors have been proposed.

Reactor manufacturers have thought for years about floating reactors, which would sit on barges, and their technical specifications. Westinghouse designed several plants with baskets of ice in the containments to absorb excess energy in an accident. These were built on land, but the containments were smaller and thus potentially better suited to being built on barges, if a utility wanted to do so.

And in November 2024 Westinghouse signed an agreement with Core Power to explore putting Westinghouse’s eVinci microreactor on barges for near-shore use.

Dig Deeper

Nine Illinois Communities Are Interested in Nuclear

Early this year, Illinois repealed its 1987 moratorium on new reactors, and went looking for potential hosts for new nuclear deployment in the state. Nine communities have raised their hands.

Six already have reactors, including Constellation’s Clinton plant, which already has an early site permit.

One has a decommissioned coal plant and another has a coal plant that will retire soon. And the University of Illinois Urbana-Champaign is continuing to pursue a demonstration reactor that would replace natural gas in making steam for the campus heating system.

Dig Deeper

Thanks for reading!

Share Nuclear Notes

Nuclear Notes is produced by the Breakthrough Institute, and covers the policy, regulation, technology, and business of advanced nuclear energy in the United States and beyond.

Every Thursday, we track what’s really going on in the field: the new rules moving through the Nuclear Regulatory Commission, the advanced reactors moving from design to deployment, the companies going public and the utilities merging, and the executive orders and acts of Congress reshaping how the country builds. We explain not just what happened, but why it matters and how the pieces fit together.

Share Nuclear Notes

Trump Says Yes to Saudi Enrichment

For over a decade, the United States has been deliberating and negotiating a nuclear deal with the Kingdom of Saudi Arabia. Over many years, and multiple administrations, talks have progressed, stalled, regressed, and repeated.

In November 2025, the White House announced agreements with Saudi Arabia, including a long-anticipated civilian nuclear cooperation agreement. But the “Joint Declaration on the Completion of Negotiations on Civil Nuclear Cooperation” was not a 123 Agreement.

Section 123 of the Atomic Energy Act governs the transfer of U.S. civilian nuclear technology, equipment, and materials to foreign countries. These agreements require congressional approval and are mandatory for American civilian nuclear technology to be exported.

This week, the Trump administration announced reaching a broad nuclear agreement with the Saudis, which was formally signed yesterday. Most notably, the agreement could eventually allow the Saudis to enrich uranium, which has been the sticking point for years. The New York Times also reported that the agreement’s provisions may limit the ability of international inspectors to watch for the diversion of nuclear materials for weapons. Notably, the United States, not international inspectors, would inspect to assure that enriched uranium was not diverted for weapons.

So, what does this mean? And what comes next?

Given the Trump administration’s interest in exporting more nuclear energy hardware and technology and competing for the global nuclear reactor market, namely against Russia and China, the deal with Saudi Arabia should not be surprising. Trump’s concessions to Saudi Arabia in the deal are surprising.

The United Arab Emirates signed a 123 agreement with the United States before construction of its four-reactor Barakah complex, and that included a ban on enrichment and on reprocessing spent fuel to recover plutonium. That is now referred to as the “gold standard,” but Saudi Arabia has refused to agree to those terms.

Last year, Breakthrough wrote that the details of the agreement would carry enormous weight, arguing that a well-crafted 123 agreement should build in safeguards, including robust verification measures, close cooperation with the International Atomic Energy Agency, and prohibitions on reprocessing spent fuel. Breakthrough also said that it should defer on sensitive issues, like enrichment, or create an alternative mechanism to keep concerns in check.

As reported in the Wall Street Journal, the agreement would bar reprocessing for military purposes. As for enrichment, reportedly, there will first be a two-year study to examine the value of enrichment for Saudi Arabia. If the study concludes that Saudi enrichment is appropriate, a U.S. company would build and presumably operate the facility under a “black box” arrangement, where the enrichment technology would not be transferable to the Saudis. If the U.S. were to renege down the line, the Kingdom wouldn’t be allowed to carry out enrichment on its own or with a different foreign partner for a decade.

Opinions are swirling on whether the decisions on enrichment and reprocessing are disastrous or practical. The text has not been made public, but the details will undoubtedly face opposition in Congress.

Two factors are driving the kingdom’s push for nuclear energy: 1) reducing oil consumption in its electric sector, which would make more oil available for export, and 2) competing with its neighbors. The United Arab Emirates’ Barakah plant, built by South Korean firms with mostly South Asian labor, based on a Westinghouse design, is an international benchmark for on-time, on-budget construction. Egypt is building four large pressurized water reactors in partnership with the Russian state nuclear monopoly. And, more acutely, Iran has been enriching uranium to near weapons-grade levels.

Some have argued that a Saudi civilian nuclear program would push Iran to complete the steps to build a nuclear warhead, which would drive Saudi Arabia to acquire them too, as the Kingdom has said publicly, multiple times. The ongoing war only exacerbates these questions. An alternative to consider is that blocking engagement altogether would not have eliminated Saudi Arabia’s long term strategic calculations.

The terms, that are still yet to be seen, may leave open the possibility that Saudi Arabia could eventually use its civilian nuclear program to get weapons material. It may also be the best result possible after 20 years of negotiation with Saudi Arabia. Time will tell.

Dig Deeper

NRC License Renewals Were “Reasonable,” Appeals Court Rules

In a major victory for keeping reactors on line, the D.C. Circuit Court of Appeals has rejected an argument that the NRC failed to consider climate change and aging plant equipment when it set up the rules for extending plant licenses.

Two old-guard anti-nuclear groups, Beyond Nuclear and the Sierra Club, claimed that the NRC had not followed the requirements of the National Environmental Policy Act, but the court ruled that the NRC’s update of its Generic Environmental Impact Statement in 2024 was “reasonable.”

“We find no basis to conclude that the Commission acted arbitrarily by failing to discuss in greater detail the aging or climate-related inputs in its severe-accident risk analysis,” the decision said. Aging components could increase accident risk, the decision said, but the NRC also has “enforceable regulatory requirements specifically designed to manage aging,” and accounts for uncertainty “through an assumed failure rate and a wide margin of error.” Therefore the court found that the issues were considered in the decision, and that the agency deserved deference on the best way to consider them.

Plants in the current fleet were licensed for 40 years. That period was often used for accounting purposes, and within the industry, many experts believed that they could be obsolete by the end of that period. But the plants have proven remarkably durable, and the Commission has approved 20-year extensions for 94 reactors, and 16 extensions for an additional 20 years, which would allow 80 years of operation, presuming that all other requirements are met.

Earlier this month the Commission posted a proposed streamlining of the license renewal rules, following up on an Executive Order issued by President Trump in May, 2025. It has already promised to complete reviews in 12 months, rather than the current 22-month schedule.

Beyond Nuclear and the Sierra Club took the counter-intuitive position of arguing that, because of climate change, the government should shut down an enormous fleet of zero-carbon energy producers. And some extreme climate conditions, like heat waves, result in sharply increased emissions from the power sector, as utilities call on inefficient fossil-powered peaker plants.

Beyond Nuclear said that the decision showed “a shocking disregard for the ever worsening weather conditions” but did not announce any plan to appeal.

Dig Deeper

Pebble-Bed Fuel Is on a Roll

The future mix of reactor types isn’t clear, but TRISO-X thinks a lot of reactors will be running on tri-structural isotropic fuel, and has announced a $1 billion new fuel-manufacturing facility in Oak Ridge, Tennessee, that will employ about 1,100 workers. The state is chipping in $11 million.

TRISO fuel uses kernels of fissile material, uranium or plutonium, encased in heat-resistant ceramics and carbon. The heat from fission can be moved out of the core for conversion into usable energy by inert gas or by molten salt. In either case, the reactor can operate at far higher temperatures than water-based reactors, with lower pressures.

TRISO-X is a subsidiary of X-energy, which is planning its first project at a Dow plant in Seadrift, Texas, which will use the high-temperature steam for chemical processing. Amazon wants the output of four more reactors adjacent to Energy Northwest’s Columbia Generating Station in eastern Washington state, near Richland. That would be a four-module project, but Energy Northwest could build eight more. Each reactor has an electric capacity of 80 megawatts.

But the new Tennessee factory would produce enough fuel for 55 reactors.

Dig Deeper

Building Reactor Parts on Spec

Today, the NRC staff is scheduled to take up one of the many rules that may have been sensible in the 1960s and 1970s, but are completely unsuited to advanced nuclear energy. That issue is whether a supplier can fabricate parts for a reactor that does not yet have a designated owner.

The current regulations are a bit like telling Home Depot that it can’t stock 2x4 lumber until the house that they will be used for has a designated buyer. And it stymies the vision of nuclear reactors that can be factory-ordered like other capital goods that are subject to strict licensing, such as airliners.

Specifically, the NRC relies on a code issued by the American Society of Mechanical Engineers, which specifies that major safety-related components cannot be constructed or fabricated to code prior to the formal establishment or identification of an owner.

In June, the NRC took note in the Federal Register of a petition from the Nuclear Energy Institute, the industry’s largest trade association, that said, “The advanced reactor fleet intends to deploy using a variety of economic models, including factory-built reactors. Given very long lead times for component construction and the need for shorter plant construction durations, it is vital that fabrication begin well in advance of the establishment of the owner.”

Dig Deeper

Constellation, an Operator, Invests in a Construction Business

Constellation, which owns the largest fleet of reactors, has made an equity investment in Blue Energy, despite not having built a new reactor in decades. Blue Energy wants to use shipyard technology to make prefabricated nuclear plants.

“With demand for near-term power rising, Constellation’s investment will help Blue Energy meet America’s need by making new nuclear development predictable, rapidly scalable, and project financeable for the first time in history,” said Blue Energy’s CEO and co-founder, Jake Jurewicz.

The investment came through Constellation Technology Ventures. David Dardis, senior vice president of Constellation, said in a statement, ​​“Constellation is committed to exploring innovative pathways that can help accelerate the deployment of advanced nuclear technologies in the United States and allocate risk appropriately.”

Dig Deeper

Thanks for reading!

Share Nuclear Notes

Nuclear Notes is produced by the Breakthrough Institute, and covers the policy, regulation, technology, and business of advanced nuclear energy in the United States and beyond.

Every Thursday, we track what’s really going on in the field: the new rules moving through the Nuclear Regulatory Commission, the advanced reactors moving from design to deployment, the companies going public and the utilities merging, and the executive orders and acts of Congress reshaping how the country builds. We explain not just what happened, but why it matters and how the pieces fit together.

Share Nuclear Notes

Advanced Nuclear May Also Need Advanced Cooling

A hot summer and erratic rainfall are reminders that most power plants need copious amounts of cooling water. Most nuclear designs, including all the ones now operating, boil water to spin turbines and make electricity. That does not consume water, because the steam is condensed back to water for re-heating. But condensing the steam requires either large amounts of water that is raised in temperature by several degrees and then returned to a river or ocean, or a smaller amount that is evaporated.

In some locations, large cooling-water requirements are not a problem. Nuclear plants have used these systems safely for decades, generally with very limited environmental impact. But cooling water can create challenges in particular locations or during periods of heat and drought.

France is generally not short of water, but the rivers that supply cooling water are so warm this summer that some plants have had to shut down or throttle back. Électricité de France, the national operator, has reduced nuclear output by 6.3 gigawatts, which is about 14 percent of total power demand.

The problem isn’t limited to rivers in France; in 2012, one of the two reactors at Millstone Point in Connecticut had to shut down because the Atlantic Ocean had gotten warmer than the designers ever anticipated, and the temperature of the cooling water exceeded the limit set in the plant’s license. This temperature limit on the cooling water exists because if the river or ocean water is too warm, it won’t absorb enough heat to condense the steam back into water in the primary loop. When the plants were designed, in the 1960s and 1970s, engineers did not bother to figure out precisely what the upper temperature limit should be because they did not anticipate the Atlantic Ocean getting so warm. But in recent years they have sharpened their pencils and figured out that the plants could safely operate at higher temperatures.

But refining the calculations has not been enough in some instances, where reactor operations have actually been curtailed.

How, then, to assure cooling for four giant reactors in the hot, dry panhandle of Texas? That is a problem for Fermi America, a start-up that leased land from Texas Tech outside Amarillo and announced plans to build 11 gigawatts of generation, including four Westinghouse AP1000 reactors. The rest is combined-cycle natural gas units, which burn gas in a machine resembling a jet engine, and use the waste heat to boil water into steam to make more electricity.

Fermi’s co-founder, Toby Neugebauer, said that his company “isn’t some out-of-town operation parachuting in. Our leadership is from West Texas — we grew up on this dirt, and we care about the land and its resources.” Plants like Millstone have no cooling towers and draw water directly from the oceans, returning it slightly warmed. But that idea won’t help in northern Texas.

There, the usual solution is a cooling tower. Plants with cooling towers pour water over pipes filled with hot water, and let evaporation on the outside of the pipes do the cooling of the water inside. But these still use substantial amounts of water, visible as steam above the towers.

The numbers vary with atmospheric conditions, but a cooling tower may evaporate as much as 800 gallons per megawatt-hour, or in a 1,000 megawatt reactor, 800,000 gallons an hour. That is a challenge in some locations.

Nuclear plants use more cooling water than coal plants of the same capacity, because some of the waste heat in a coal plant goes up the chimney. They also use more water than combined-cycle natural gas plants because the portion of those plants’ output that comes from the jet engine does not make steam. But the jet’s hot exhaust is used to make steam, which does have to be condensed.

But a solution for nuclear may be to use air instead of water for cooling.

In December, Fermi America announced a memorandum of understanding with a Hungarian company, MVM EGI Zrt., for a hybrid system that would use air to cool the steam back into water. MVM already sells such systems for fossil-fired plants.

Some anti-nuclear groups have seized on the water problem. The Institute for Energy Economics and Financial Analysis pointed out in a report last week that no nuclear plant now uses such a hybrid system, and claimed it was unproven and unlicensed.

But it is proven. Some fossil-fueled plants make substantial use of air cooling, some only seasonally, when river water is warm or scarce. The Energy Information Administration calculated in 2018 that about 3 percent of U.S. generation uses air cooling, although none of that is nuclear.

Southern Nuclear evaluated air cooling for its Vogtle plant before the plant was built. One problem is that the fans needed to move the air consume a significant amount of the plant’s power. (The precise amount depends on the ambient air temperature). Southern concluded that an air-cooled condenser was “not feasible from a reliability, cost, or environmental standpoint.”

NuScale Power found otherwise. It developed a detailed air-cooled design, which was intended for its lead plant at the Idaho National Laboratory. Using an air-cooled design produced a penalty of 5 to 7 percent of the plant’s electricity output, depending on ambient air temperature. If the region were dry enough, that cost would be acceptable. But that project was scrapped for other reasons.

The need for water may be a weak spot for all thermal-electric generators, but nuclear energy is well-positioned for a drought-prone world. Located in the Arizona desert, the Palo Verde Nuclear Generating Station is long known as the only large nuclear plant in the world not built near a major body of water. To cool its reactors, the plant relies on a 40-year agreement with metropolitan Phoenix to purchase treated wastewater annually. Nuclear is also a potent source of energy for making drinking water from the oceans.

Dig Deeper

A Mining Giant and A Potential Nuclear Giant Settle on Terms

Australia will begin exporting uranium to India, twelve years after a trade deal was initially struck. The delay came from Australia’s insistence that its uranium not find its way into India’s nuclear weapons program.

India never signed the Treaty on the Non-Proliferation of Nuclear Weapons of 1970, and exploded what it called a “peaceful nuclear device,” code-named Smiling Buddha, in 1974. In response, major nuclear exporters embargoed India for decades.

But India has a huge potential market for nuclear energy. The country is short of power—annual electricity consumption in India is about 1,400kilowatt-hours per person, compared to about 12,000 in the United States—and struggles with air quality from coal pollution. It has 24 reactors in service, with a total of about 8.8 gigawatts, about ten more under construction, and ten planned after that. Its goal is 100 gigawatts by 2047.

The country has a mix of reactors, including an adaptation of the Canadian CANDU design that runs on unenriched uranium. The Russian state nuclear monopoly is building a complex of six pressurized water reactors at the Kudankulam nuclear complex in Tamil Nadu. Two are already in operation. India currently imports its uranium from a number of countries including Russia, Kazakhstan, and Canada.

The Indian prime minister, Narendra Modi, and the Australian Prime Minister, Anthony Albanese, signed an agreement in Melbourne last week. Price and volume were not disclosed.

India has only low-grade uranium ore, although it does have an abundance of thorium, a radioactive material that is not fissile, but can be converted into the fissile isotope uranium-233 by absorbing a neutron in a reactor. It has been developing a thorium fuel cycle. One company, with help from the Department of Energy, has developed a fuel package that could permit that transformation inside a CANDU. But another route is to import uranium.

Dig Deeper

A Lot of Small Companies Have a Lot of Support on Wall Street

The publicly traded companies that are pure-play small modular reactor developers have a collective market value of $21.2 billion, according to a recent tally by Robert Bryce, who is a nuclear advocate but is skeptical of the prospects of some of the companies.

Two-thirds of the market value is in two companies, Oklo and X-energy. And Holtec International, newcleo, and NuCube Energy plan initial public offerings as well.

Holtec filed paperwork with the Securities and Exchange Commission last week for an Initial Public Offering, stressing its plans to build small modular reactors of its own design.

The two nuclear developers that may have the strongest short-term prospects aren’t on the pure play list. The first is GE Vernova. A GE Vernova’s BWRX-300 reactor is already under construction in Ontario, with strong indications of sales of more, but it isn’t a pure play; the company also makes gas turbines and other electrical equipment. The second is Westinghouse, which could see orders for a fleet of ten big AP1000 reactors, and isn’t publicly traded at all. It is privately held by Brookfield Asset Management (a Canadian turn-around firm), and Cameco (a Canadian uranium mining company).

Dig Deeper

Fusion Goes Public Too

This week, General Fusion, of Richmond, British Columbia, became the first pure-play fusion company on Wall Street. It went public on the Nasdaq. A second fusion company, TAE Technologies, based in California, is supposed to go public later this year, in a merger with Trump Media & Technology Group Corp.

General Fusion hopes to demonstrate a test apparatus soon that will generate more electricity than it requires to create fusion, and to be in commercial operation by 2035.

Politico calculates that the fusion industry as a whole has raised more than $14 billion since 2021, although a commercial-scale fusion reactor is still years away.

And a Munich-based company, Proxima Fusion, announced this week that it had raised €411 million, about $470 million, which would value the company at €2.4 billion, or $2.75 billion.

Dig Deeper

No Restart Yet, But TMI-1 Can Store New Fuel

The Nuclear Regulatory Commission has given permission to Constellation Energy to accept new fuel for the reactor now known as the Crane Clean Energy Center.

When the company closed the plant in September, 2019, it had a large inventory of partially-used fuel. But to save money in the decommissioning process, operators bundled up the fuel assemblies that were only one-third or two-thirds used with completely used fuel, to minimize the number of dry casks they would need. When Constellation decided in late 2024 to re-open the reactor, it ordered new fuel.

Dig Deeper

Thanks for reading!

Share Nuclear Notes

Nuclear Notes is produced by the Breakthrough Institute, and covers the policy, regulation, technology, and business of advanced nuclear energy in the United States and beyond.

Every Thursday, we track what’s really going on in the field: the new rules moving through the Nuclear Regulatory Commission, the advanced reactors moving from design to deployment, the companies going public and the utilities merging, and the executive orders and acts of Congress reshaping how the country builds. We explain not just what happened, but why it matters and how the pieces fit together.

Share Nuclear Notes

How Does Nuclear Caution Mesh with High-Tech Urgency?

Much of the impetus for new nuclear construction, and some of the money for advanced nuclear designs, comes from high-tech Silicon Valley firms that need electricity and want to bring their culture of fast innovation to an industry with big potential but a high degree of inertia.

In an insightful blogpost, José N. Reyes, the co-founder of NuScale Power, points out that this could be a helpful infusion of resources and skills, or it could be a collision.

There are big differences between the “move-fast-and-break-things” school of business management and the more cautious approach of the nuclear industry.

“Tech companies typically build simple versions of products, iterating and perfecting them over time,” Reyes wrote. “You simply cannot release a ‘beta version’ of a commercial nuclear reactor, hoping to fix bugs as they arise in real time.”

And he cited a recent comment by the Nuclear Regulatory Commission’s Advisory Committee on Reactor Safeguards, which reviews all license applications, stating that some reports submitted to the Commission by reactor developers lack the technical detail needed for evaluation. The Committee’s comments conveyed that rushed applications may seem to demonstrate progress toward licensing but they waste NRC resources.

Reyes pointed out that tech companies often use a “fail fast” strategy, trying out ideas promptly to see if they will work. “This approach may be suitable for a test reactor in a highly controlled laboratory environment, however the subsequent transition from test reactor to commercial nuclear plant still requires an in-depth NRC safety review and licensing process,” he wrote.

Which culture will prevail?

NuScale may have a different outlook on the licensing process since it has been through it and, after great effort and expense, has a licensed design. At the other end of the spectrum is Oklo, a Silicon Valley start-up, which applied for a license in March 2020 but saw the NRC reject it and cease its evaluation in January 2022 because, the regulator said, the application was not complete enough. Oklo is trying again.

And Last Energy, Deep Fission, and Valar Atomics are trying to get past the NRC licensing process and move forward fast by suing the NRC and challenging its jurisdiction.

Kairos Power is taking a different tack, adopting an approach similar to that of Space-X–building, testing, learning, and starting over with the lessons learned. But Kairos is doing that with components and small test reactors, not the finished product.

All these companies are a stark contrast to the ones that designed the power reactors now in use in the United States. All were long-standing pillars of the energy industry, with extensive experience in coal and natural gas, and were modifying the design of those plants to take advantage of a new heat source. They were using a familiar material, ordinary water, and already had experience with many of the pumps, valves and instruments that their plants would need. Today’s designers are starting with a clean sheet, using molten salt or metal in some cases, and have little background in manufacturing.

And in the first round of nuclear construction, the heavy equipment companies—Westinghouse, General Electric, Combustion Engineering, and Babcock & Wilcox—were selling to utilities, which are technologically conservative. Today the customers include tech companies, hyperscalers, a chemical company that wants steam rather than electricity, and, potentially, a variety of enterprises that want close-at-hand, reliable generators to power their operations.

The Electric Power Research Institute, a non-profit utility consortium, captured some of the culture clash in an article describing a meeting in London of the Global Forum for Nuclear Innovation. Rather than engineering presentations, the event began with a hip stage performance by Jon Chase, who defines his specialty as “rapscience.”

He sang, “so, on the one hand, there is safety. On the other is innovation. One relies on caution and the other inspiration, but the two must function hand in hand for any operation to succeed.”

Dig Deeper

Four for the Fourth

Aalo Atomics’ Critical Test Reactor reached initial criticality a few minutes after midnight on July 4 at the Idaho National Laboratory, and is the fourth advanced reactor to meet that deadline, set by an executive order fourteen months ago. The company said it demonstrated the nuclear components of a 10-MW reactor (although not other parts of the system).

“Criticality has validated our supply chain, reactor physics, control systems, and fueling procedures at commercial scale,” the company said in an announcement, noting that it had gone from groundbreaking to initial criticality in less than eight months.

President Trump’s Executive Order 14301, “Reforming Nuclear Reactor Testing at the Department of Energy,” signed in May of 2025, called for at least three initial criticalities by independence day of this year.

All four are micro-reactors, producing power at levels similar to a large diesel generator.

Antares Nuclear’s reactor, Mark-0, achieved criticality in June, under the Department of Energy’s Reactor Pilot Program. Antares credited support from the U.S. Army, and says it will deploy on military bases in 2028. It is meant to be delivered by truck, and can be shut down and moved to another location if needed.

Valar Atomic’s Ward 250 reactor also sustained a criticality in June, at a laboratory in Utah. It has a capacity of 5 megawatts and is intended to be transportable.

Valar reached the same milestone with a different core design last November.

A third company, Deployable Energy, announced on July 1 that its one-megawatt Unity reactor had achieved initial criticality. It was part of a separate Energy Department program, the Nuclear Energy Launch Pad initiative.

Initial criticality, sometimes referred to as zero-power criticality, means that a core has achieved a self-sustaining chain reaction, usually at a power level of a few hundred watts or a few kilowatts. It produces data that can help a company apply for a license from the Nuclear Regulatory Commission, which it will need for commercial deployment. All four got test authorization for initial criticality from the Department of Energy, which is easier than getting commercial permission from the NRC.

To be a commercial product, a reactor would also need a system for converting the heat to electricity. In the case of these small reactors, the developers would also need to be able to produce many copies. Microreactors are something of a niche product, intended for places that have a high need for reliability, or are located far from the grid, often in places where delivery of diesel fuel is difficult.

Dig Deeper

Vogtle 4 Becomes an Industry Standard

The Nuclear Regulatory Commission has agreed to review an application by Westinghouse to amend the design certification for the AP1000 to match Georgia Power’s Vogtle 4 reactor. This would essentially absorb Vogtle 4 specifications, amendments, and changes into the January 2006 AP1000 design approval, and ameliorate a problem with the Part 52 licensing procedure under which the plant was built: Every deviation from the pre-approved design required a license amendment. By making Vogtle 4 the standard, future AP1000s will presumably require very few amendments. The only foreseeable variations would be for local geology and other site-specific considerations.

Previous NRC regulations, conceived before this problem became obvious in Vogtle’s construction, would have frozen the certification until 2043. The NRC gave the company a one-time exemption to allow it to apply for the revision now. Westinghouse hopes that the regulators will approve the updated certified design later this year. That could slightly simplify the task envisioned by the Trump administration: getting five twin-unit AP1000 plants under construction.

Dig Deeper

Report: Global Nuclear Market Will Be Strong, and Russia Will Benefit

Globally, the prospects are good for a major expansion of nuclear energy, according to the Nuclear Energy Agency, but among planned and proposed projects around the world using imported technology, Russian VVER design dominates, comprising 40 percent of all internationally procured reactors. And more than half of Russia’s nuclear industry is manufacturing units for export.

The Nuclear Energy Agency, part of the Organisation for Economic Co-operation and Development, gives only passing mention to reactor technology beyond light water, the type that now dominates, and says that small modular reactors will not enter the market until the mid-2040s, and in only a modest way, even under the most optimistic scenario. And tripling nuclear capacity by mid-century would take a transformative effort, the report said.

Russia’s war against Ukraine, which made Europe’s largest nuclear plant, Zaporizhzhia, an intermittent target, has sharpened the appetite of governments for nuclear energy, the report said, because reactors substitute for fossil fuel imports.

Dig Deeper

Two More Nuclear Companies Head to Wall Street

The Canadian firm that owns the rights to that country’s pressurized heavy water reactor technology has notified the NRC that it will apply for a license in the U.S.

The CANDU reactor (for Canada Deuterium Uranium) runs on unenriched uranium and heavy water. Few have been built recently, but several have been refurbished. AtkinsRéalis, an engineering and project management company, will seek to market a 700-megawatt version in the U.S. The move comes as an American/Japanese design, the GE Vernova Hitachi BWRX-300, is under construction in Ontario.

In addition to Canada, CANDUs operate in South Korea, China, Argentina, Romania and India. Canada recently committed itself to developing a national nuclear energy strategy and expanding export markets.

Dig Deeper

Thanks for reading!

Share Nuclear Notes

Nuclear Notes is produced by the Breakthrough Institute, and covers the policy, regulation, technology, and business of advanced nuclear energy in the United States and beyond.

Every Thursday, we track what’s really going on in the field: the new rules moving through the Nuclear Regulatory Commission, the advanced reactors moving from design to deployment, the companies going public and the utilities merging, and the executive orders and acts of Congress reshaping how the country builds. We explain not just what happened, but why it matters and how the pieces fit together.

Share Nuclear Notes

Life, Liberty, and the Pursuit of Criticality

The July 4 deadline for the Department of Energy’s Reactor Pilot Program is nearly here, and the program has met its central goal: three advanced test reactors reached criticality on an extraordinarily compressed timeline. Antares Nuclear’s Mark-0 reached zero-power criticality at Idaho National Laboratory on June 4. Valar Atomics’ Ward 250 followed later in Utah, becoming the first DOE-authorized reactor built and operated outside the DOE national laboratory system. Deployable Energy, through DOE’s Nuclear Energy Launch Pad program, also reached criticality at INL, making it the third reactor to meet the July 4 target. Aalo is expected to follow soon.

Yesterday the Breakthrough Institute shared its thoughts: the milestone is real, but it is easy to misinterpret. Supporters may treat the program as proof that advanced nuclear has arrived and that the largest barriers to deployment have been cleared. Critics may dismiss it because these are small test reactors, operating at zero or low power, rather than commercial plants selling electricity to the grid.

But the Reactor Pilot Program was not meant to produce commercial nuclear plants by the Fourth of July. It was meant to help restore a missing process in nuclear innovation: building, testing, learning, and improving before moving to commercial scale.

Nuclear energy has often struggled to preserve that development sequence. Many reactor projects have tried to move from paper designs, modeling, and component tests directly into full commercial projects. That approach puts the first customer in the position of absorbing unresolved technical, construction, operational, and regulatory problems. When the first integrated test of a design is also the first commercial project, every issue appears at the most expensive possible moment.

The Reactor Pilot Program does not make the participating designs commercial products overnight. But it can move them further along the technology maturity curve.

Nor is the program simply public relations. The July 4 deadline was plainly chosen for effect, especially in the year of America’s 250th birthday. In an industry long criticized for producing “paper reactors,” the demonstration of real hardware has value for investors, customers, regulators, and developers themselves.

The Reactor Pilot Program does not solve every barrier facing advanced nuclear. It does not create fuel supply, manufacturing capacity, customer demand, commercial financing, or a full licensing pathway. It also does not replace the Nuclear Regulatory Commission’s role in commercial reactor licensing.

The more important test for the Reactor Pilot Program is therefore not whether three reactors reached criticality by July 4; it is whether the program helped create a repeatable pathway for nuclear developers to test real systems earlier, generate data that can inform later licensing, and move from paper designs toward safer and more credible commercial products.

Seen narrowly, the program can look too small to matter or too preliminary to count. Seen more clearly, it challenges a status quo that had become too easy to accept: that nuclear developers had to move from models and component tests directly into commercial licensing, with little room to build and learn in between. The July 4 milestone is not the finish line. It is a sign that the United States may be relearning how to turn nuclear concepts into real machines.

Dig Deeper

Risk-Informed Regulation Comes for Nuclear Waste

The Nuclear Regulatory Commission has proposed a new rule for the most active category of low-level waste that would provide a disposal pathway for material now languishing at power plants, hospitals, and other locations.

“There’s a finite amount of space to store these types of things,” Ho Nieh, the chairman of the NRC, told Power Magazine.

Commission rules establish four categories for material besides spent fuel, based on concentrations of radioactivity and the specific radionuclides in the mix. These range from Class A, including rags and protective clothing, mostly contaminated with short-lived isotopes, to Class B, also short-lived but with higher concentrations, and Class C, with higher concentrations of both short- and long-lived isotopes.

The other category, awkwardly-named “Greater than Class C,” or GTCC, often includes non-fuel materials removed from the reactor vessel, like irradiated control rods. When a nuclear plant is decommissioned, one or two of the dry casks are usually filled with this material. Some filters used to keep cooling water clean can also slip into this category. Other materials include sealed sources used for industrial radiography. The industry’s assumption has been that the materials will eventually follow the spent fuel to a geologic repository, but the decades-long search for such a repository now promises to stretch for decades more.

There are already disposal paths for A, B, and C, but not GTCC. Repositories in Texas and Washington State accept A, B, and C for shallow burial.

In rewriting the rule, the agency is following Executive Order 14300, “Ordering the Reform of the Nuclear Regulatory Commission,” and is proposing to set disposal requirements based on the radiological characteristics of the material and not the material’s source.

The proposed rule would not establish a disposal facility; it would only create a pathway for building one. A private developer would still have to get a state to approve and build the site. The idea is for burial at a depth and in packaging appropriate to the specific material involved.

Nuclear waste has recently drummed up renewed debates, especially among those opposed to advanced reactors. The Trump administration has responded by seeking to establish “Nuclear Lifecycle Innovation Campuses,” sites at which private companies would accept used nuclear fuel to store and/or dispose of, and would most likely recover plutonium created in reactor operations and unused uranium through used fuel reprocessing. These sites, as a byproduct of operations, would create additional GTCC waste, but they could also dispose of it.

Tennessee, Utah, Idaho and Nebraska have said publicly they are interested in hosting such facilities, among other candidates.

Dig Deeper

Mapping the Nuclear Buildout

Start exploring America's nuclear energy future, with the Breakthrough Institute’s new tool for exploring how the U.S. energy mix could evolve under different cost and learning rate scenarios through 2050—with layers for conventional nuclear, advanced reactor deployments, coal-to-nuclear conversion sites, and uprate and restart opportunities at existing nuclear plants.

Dig Deeper

Gearing Up for Reactors At Sea

The Coast Guard and the NRC are anticipating license applications for building nuclear-powered ships or floating reactors, and have updated a 53-year-old memorandum of understanding to coordinate their activities. It clarifies that the NRC is responsible for regulating reactor safety and the Coast Guard for vessel safety. It also sets schedule goals.

A cargo ship would seem to be a good application for a small modular reactor. But there are numerous regulatory problems, of which NRC-Coast Guard coordination is just one. The ships would be regulated by the country whose flag they fly, and there are very few U.S.-flag cargo ships. Most carry the flags of countries with no nuclear expertise, like Liberia or Panama.

Dig Deeper

Canada Eyes the U.S. Market

The Canadian firm that owns the rights to that country’s pressurized heavy water reactor technology has notified the NRC that it will apply for a license in the U.S.

The CANDU reactor (for Canada Deuterium Uranium) runs on unenriched uranium and heavy water. Few have been built recently, but several have been refurbished. AtkinsRéalis, an engineering and project management company, will seek to market a 700-megawatt version in the U.S. The move comes as an American/Japanese design, the GE Vernova Hitachi BWRX-300, is under construction in Ontario.

In addition to Canada, CANDUs operate in South Korea, China, Argentina, Romania and India. Canada recently committed itself to developing a national nuclear energy strategy and expanding export markets.

Dig Deeper

Just How Dead Is German Nuclear?

The German word that has most firmly entered the U.S. energy vocabulary is “Energiewende,” meaning transition to renewables. Due to a second phenomenon described by another German word, “Atomausstieg,” meaning nuclear phase-out, Germany has increased costs and carbon emissions, and become a net energy importer. But German public opinion is returning to favoring nuclear energy, and a group of German nuclear technology experts has renewed a push to get the government to change its mind.

A deeper analysis identified two reactors with a total of 2.7 gigawatts of capacity that would require only maintenance and minor repairs, as well as the rehiring of staff and the purchase of fuel, that could be restarted in one to three years and produce energy at a price of €31 per megawatt-hour. Two more reactors with another 2.7 gigawatts of capacity were clearly able to restart in four to eight years, although they were missing parts of the turbine island or nuclear steam supply system. Another five units with 6.7 gigawatts of capacity were potentially in that category. The cost estimates are below wholesale electricity prices and include installing a new instrumentation and control system and training simulator, plus the cost of re-hiring staff.

The suggestion is that Germany follow the United States, where three reactors are being put back into service. Maybe our energy vocabulary can import a third German word, for ‘restart.’

Dig Deeper

Thanks for reading!

Share Nuclear Notes

Nuclear Notes is produced by the Breakthrough Institute, and covers the policy, regulation, technology, and business of advanced nuclear energy in the United States and beyond.

Every Thursday, we track what’s really going on in the field: the new rules moving through the Nuclear Regulatory Commission, the advanced reactors moving from design to deployment, the companies going public and the utilities merging, and the executive orders and acts of Congress reshaping how the country builds. We explain not just what happened, but why it matters and how the pieces fit together.

Share Nuclear Notes

DOE Will Inject Help for Supply Chain

The Department of Energy plans to provide $17.5 billion in low-interest loans to jump-start construction of ten Westinghouse AP1000 reactors, not for the construction projects directly, but for the major components.

The idea is to build up the supply chain for reactor vessels, steam generators, reactor coolant pumps, and other big parts, and to lower the cost of those components by encouraging suppliers to tool up to build multiple copies.

The effort follows President Trump’s announcement in May, 2025, that he wanted ten new large reactors under construction by 2030. The new idea is to finance parts for five twin-reactor projects, like Georgia Power’s two-unit expansion at Vogtle, near Augusta, Ga.

“These conditional loans will play an important role in reviving the supply chain needed for America to once again build large-scale commercial reactors,” said the Energy Secretary, Chris Wright, in a statement. “They will also help accelerate the timeline of building those large-scale reactors by up to three years, lowering construction costs and ensuring the United States is able to deliver on President Trump’s bold and ambitious energy addition agenda.”

Working on multiple copies of identical reactors at the same time could introduce greater flexibility, with the ability to transfer components among projects as construction progress required. Serial development would also help develop a cadre of craft workers and construction managers who could move from project to project. While ten reactors might be under way at one time, their schedules for starting and completion would likely differ.

Interest costs are a major component of nuclear project costs, because nuclear is capital-intensive and because construction loan payments start years before the plant can generate energy and revenue. The Department of Energy plan works out to $1.75 billion per reactor, a modest portion of the building expense.

The announcement did not specify an interest rate, but indicated that Westinghouse had signed letters of intent with seven potential partners. This agreement would fund five.

The AP1000 is a modest departure from current-generation pressurized water technology. Engineers refer to current models as “generation 3,” and the AP1000 as “generation 3+.” Both Gen 3 and Gen 3+ models use water to slow down the neutrons released in fission, to a speed more likely to cause additional fissions, and to move heat from the reactor so it can be converted into electricity. But the AP1000 has fewer critical valves and pumps, and less safety-grade electrical cable, and it relies heavily on natural, fail-proof forces, like gravity and passive heat removal. The letters in the model number stand for “Advanced Passive,” and the number is a rounded-down version of the output in megawatts, which is actually about 1,100.

Reactors in the Energy Department’s Advanced Reactor Demonstration Program have moved away from water, using molten salt or inert gas or other materials as a heat transfer agent, allowing higher temperatures at lower pressures, making construction easier, and generating more useful steam. Such models are known as Gen 4 reactors.

But the AP1000 has a major advantage over more advanced technologies: not only does it have a licensed design, but copies are up and running, and it has detailed blueprints. It still needs major cost reductions, though, to make big market inroads. The Vogtle project is the only one of its kind in the United States so far, but China has built two twin-unit AP1000s, and is now building CAP1000s based on the Westinghouse design.

In a major change, the department said that the projects would be jointly owned by Westinghouse itself and by a utility or other developer. Westinghouse and the developer would each have to put up $500 million before the loan could be issued. The loans will be made to a special purpose entity only after those investments are made. In the past, Westinghouse has been a supplier, not an owner, although it did step in and take a bigger role in finishing the Vogtle project.

Dig Deeper

Another Non-Utility Entrant

A company called Elementl Power, which describes itself as “an independent developer of utility-scale nuclear power projects,” has announced plans to build up to five GE Vernova Hitachi BWRX-300 reactors at a site about 100 miles southeast of Columbus, Ohio, on the Ohio River. It has already applied to the regional grid operator, the PJM Interconnection, for permission to connect up to 600 megawatts of generation.

The project is in an early stage and its prospects are uncertain, but the proposal itself illustrates the uncertainties around the business model for advanced nuclear energy. Elementl is not a utility, and says that “this project will not be funded through electric customer rates.” That would make it a “merchant” plant, a generator in the deregulated system that sells energy for whatever the market will bear, through auctions run by PJM or by longer-term contract, and rents its power capacity on an annual basis to load-serving utilities that are obligated to secure enough power to supply their customers.

That is the basis on which most new generators earn their keep, but it is not a friendly structure for nuclear plants. One of the weaknesses of the deregulated electric system is that it is supposed to be technology-neutral, but in fact it favors development of power plants with short lead-times and low capital costs–a description of natural gas, not nuclear. All the power reactors now in service were built by utilities that could count on reimbursement from captive customers, not revenue from an auction system, but most of the country has moved to the auction system.

Building a merchant nuclear plant has a challenge: one of the biggest needs is low-cost capital, meaning low interest rates, because the builder has to pay years of interest on the investment as it is built. But an independent generator like Elementl is likely to have to pay higher interest than an established utility. And even the established utilities with strong credit ratings have, thus far, shown great caution about signing up for reactors, leaving the field to a variety of other entities. At the moment, the two leading reactors in the Advanced Reactor Demonstration Program are, respectively, backed by a big chemical company, Dow, and investors led by Bill Gates. And the Dow reactor may mostly supply steam for industrial use rather than just electricity for the grid.

The BWRX-300 is in a slightly different category: Ontario Power Generation, a utility owned by the province of Ontario, is building one and has plans for several more. And the Tennessee Valley Authority, another government utility, would like to build one in Oak Ridge, Tennessee. That could reduce the cost and schedule uncertainties that a subsequent developer would face. Additionally, the BWRX-300, a Small Modular Reactor, is less than one-third the capacity of gigawatt-scale reactors, and thus an individual reactor becomes a smaller and perhaps more achievable project.

Elementl says that it has an “early works agreement” with GE Vernova Hitachi, which greeted the announcement warmly, as did local officials in southern Ohio.

Dig Deeper

A Second Reactor Reaches Initial Criticality

A little more than a year ago, President Trump set a goal of having at least three new reactors reach “initial criticality” by July 4. A second company, Valar Atomics, has now reached that threshold. Initial criticality, often called zero-power criticality, means sustaining a chain reaction at very low levels, a step that can produce data that validates the design of the core.

Antares Nuclear met the milestone two weeks earlier. More could do so before July 4.

Valar said that its model Ward 250, which is intended to produce 5 megawatts, reached the milestone “as a complete, fully integrated system configured for power operations.”

Dig Deeper

A Deeper Look at a Fusion Start-Up

Keith LeChien, the chief technical officer of Pacific Fusion, which raised $900 million by late 2024 and plans to deploy a commercial fusion power plant in the mid-2030s, gave some detailed answers to questions from Dan Yurman, author of the blog Neutron Bytes. The company’s fusion system uses electricity pulled from the grid to produce 100-nanosecond pulses to fuse deuterium and tritium. LeChien said the technology would use “components that can be manufactured, tested, serviced, and replaced like industrial equipment.”

“Fusion’s promise is enormous — but it is hard,” LeChien said.

Dig Deeper

NJ Legislature Unanimously Follows Their Pro-Nuclear Governor

Governors of the northeastern states are falling into line to support nuclear energy. The six New England governors signed a letter pledging to include nuclear in their planning. The governor of New York told the state power authority to develop 1 gigawatt of new nuclear, and the governor of Pennsylvania has pushed to speed up the re-start of Three Mile Island. And in New Jersey, the new governor Mikie Sherrill has also pushed for new nuclear.

Legislative action has been rarer. But a New Jersey assembly committee recently unanimously approved a bill to instruct two state agencies to “procure advanced nuclear energy facilities,” and the legislature in Trenton is moving ahead on other fronts.

Dig Deeper

Correction

Nuclear Notes last week incorrectly described the coolant in Aalo’s 50-megawatt design. It is liquid sodium.

Share Nuclear Notes

Nuclear Notes is produced by the Breakthrough Institute, and covers the policy, regulation, technology, and business of advanced nuclear energy in the United States and beyond.

Every Thursday, we track what’s really going on in the field: the new rules moving through the Nuclear Regulatory Commission, the advanced reactors moving from design to deployment, the companies going public and the utilities merging, and the executive orders and acts of Congress reshaping how the country builds. We explain not just what happened, but why it matters and how the pieces fit together.

Share Nuclear Notes

New York Pencils Out New Nuclear

Two New York State agencies have released an Advanced Nuclear Policy Options Paper on the options for building a fleet of new nuclear reactors. However, as the report notes, government experts predict that neither utilities, which were the companies that built the existing reactors, nor other potential developers, will have an appetite for construction at the high costs projected unless state and federal actors step in to recognize the value of energy that is carbon-free, highly reliable, a stimulus to the local economy, and a source of energy independence.

“Market revenue from wholesale electricity generation and capacity markets does not suffice to make projects financially viable,” said the study.

The two agencies are seeking to advance a plan by the governor, Kathy Hochul, who told the New York Power Authority to develop one gigawatt of new nuclear capacity, and who wants someone to build four more gigawatts. While the analysis was specific to New York, the broad outline holds true across the country. And a detailed analysis of policy options by a state is rare.

The report pointed to two steps that would be particularly effective for New York and other states, and the federal government, to take: establish a stable policy environment with a predictable set of benefits, and include mechanisms to lower interest rates.

In fact, the report points to lowering interest costs as the most important step for making new nuclear plants viable. In some scenarios, the report said, cutting interest rates would lower the revenue requirements of a new reactor by more than $100 a megawatt-hour.

Nuclear plants are particularly vulnerable to high interest costs, because they take years to build, and interest on the construction loans piles up before the reactor enters service.

The Energy Department could offer low interest loans, the state itself could borrow money at its preferred rate, or the New York Power Authority could do so, and the government could take policy steps that would persuade lenders that the investment was not risky. That would let them lend at lower rates.

According to the report, a new light-water reactor with a capacity of one gigawatt that was receiving a zero emissions credit would still need revenue of $252 per megawatt hour, but this would come down to $160 a megawatt-hour if combined with state overrun guarantees, “and that this in turn could come down further to around $100/MWh depending on combinations with other interventions such as State equity or grants.”

Unless risk is shared, the paper says, lenders may demand such a high interest rate that the project would be impractical. Potential parties to share the risk are the state itself, “offtakers” that would buy the power, and companies that provide the engineering and construction management.

The state could also share risk by owning part of the reactor. “Partnerships between governments could take multiple forms, including: joint contracting with project developers for pipeline deployment across multiple jurisdictions, including risk sharing arrangements; joint procurement of key components to secure bulk buying discounts; expansion of contracts that might initially be entered into by one state to subsequently add participation by other states; or, for neighboring jurisdictions, partnerships that involve physical sharing of nuclear generation (i.e., through imports),” according to the study. New Jersey and the province of Ontario were mentioned as possible partners.

It said that 100-percent state ownership might lower interest costs, because the state and its agencies have a high credit rating and pay interest that is not taxable, so investors prefer them. The state can finance a plant at interest rates of five or six percent, a utility could do it at nine percent, and private-sector construction would be even higher, the report said. But a private sector participant would be helpful to “help ensure cost control.”

Another possibility is that third parties might buy clean-energy credits voluntarily. (This might make more sense than companies assuring customers that their products are “carbon-neutral” by planting trees, a claim difficult to verify).

The report also details the relative merits of large light-water reactors (In practice, the AP1000) and multiple small modular reactors. The first project is the riskiest, and an SMR as a first project would represent a smaller risk, it noted.

A large reactor would have lower costs than a small one, at least in the first iteration, but costs from small modular reactors could drop faster because there would be more projects to learn from.

And building the small ones could induce a manufacturer to build in-state factories for production of major components, a big economic advantage. But it is not clear whether that would be true of the GE-Vernova Hitachi BWRX-300, the SMR that appears to be in the lead, with one already under construction on the Canadian shore of Lake Ontario; there is already a plant in Ontario to make those components.

The report also considered whether the plants should be built simultaneously or in sequence, and whether they should all be the same technology.

“Building a sustained pipeline of reactors, regardless of technology, across New York State would unlock powerful learning-by-doing benefits. Delivering projects in sequence would drive efficiencies, strengthen execution, and cultivate a highly skilled, in-State nuclear construction workforce.”

Promising a series of reactor builds would also make it easier to attract students to training programs, the report said. But there are conflicting factors; perhaps it would be better to pursue projects in parallel, rather than in sequence, to get as many started as possible while federal tax credits are available. Investment Tax Credits are scheduled to phase out in the early 2030s.

There might be supply chain bottlenecks that would be ameliorated by building two different models; there might be economies of scale by building a single model.

Or if it proceeded on a case-by-case basis, the state might switch technologies in the future if a particular model proved successful elsewhere.

Dig Deeper

Breakthrough Comments on the NRC’s Proposed Rules for Large-Volume Reactors

How quickly the United States can deploy a new generation of advanced nuclear reactors will depend in large part on whether the NRC can license them efficiently and at scale. The NRC’s proposed “Part 57” rule is designed to enable exactly that—make licensing faster, more standardized, and more repeatable by tailoring regulatory requirements to the consequences a reactor poses. Reactors that cannot cause significant harm beyond their site boundary could qualify for streamlined review, approval as a standardized design, and manufacturing-based licensing. But the proposed rule is ambiguous about its own purpose: it is framed around a loosely defined category of reactors rather than around the high-volume licensing it is meant to enable—an ambiguity that could generate boundary disputes, complicate implementation, and weaken the rule’s long-term durability.

The Breakthrough Institute submitted a comment to the NRC recommending changes to resolve this and other structural issues. Most importantly, BTI urged the NRC to make clear that Part 57’s central purpose is high-volume licensing, not a technology category, and to ensure its eligibility criteria, security requirements, environmental review, and emergency planning are calibrated to demonstrated risk and administrable at scale. Breakthrough also recommended aligning Part 57 with the NRC’s broader advanced-reactor framework (Part 53) so that developers can move efficiently from first-of-a-kind demonstrations to repeated commercial deployment without re-litigating settled issues. As Breakthrough’s comment puts it, “[w]ith changes, Part 57 can become a durable and effective licensing framework because it is more focused, not because it is less rigorous.”Reform is essential, because the NRC is geared toward issuing a handful of licenses every year, and if microreactors are successful, they will be deployed by the dozens or hundreds.

Dig Deeper

Fusion’s Arrival Date Is Uncertain, but Tennessee Says It’s Ready…

In Washington, the Nuclear Regulatory Commission is still working out the regulations that will govern fusion, but the Tennessee Department of Environment and Conservation has established its licensing requirements.

“Tennessee has been named the top state in the nation for nuclear industry growth, and for good reason,” said the commissioner of the department, David Salyers, in a statement. “This latest step supercharges our reputation as the global hub for nuclear innovation and positions us as the most responsive state to new advanced nuclear companies.” The state says its regulations are the first of their kind in the nation.

Dig Deeper

…And Washington State May Be a Step Ahead

Helion, a fusion company that has already started construction of a plant, in Malaga, Washington, says it has received two licenses from the Washington State Department of Health. The NRC regulates fusion under a category used for nuclear byproducts, and Washington is a “delegation state,” meaning that its state agencies are delegated by the federal government to enforce federal regulations locally.

Helion has a contract to supply Microsoft with 50 megawatts of power from fusion by 2028, but skeptics say that the feasibility of its design has not been established.

Dig Deeper

Correction

Nuclear Notes stated erroneously last week that Aalo’s 50-megawatt helium-cooled design used HALEU, fuel enriched to nearly 20 percent. Its design is for uranium at enrichments of 10 percent or lower.

Nuclear Notes is produced by the Breakthrough Institute, and covers the policy, regulation, technology, and business of advanced nuclear energy in the United States and beyond.

Every Thursday, we track what’s really going on in the field: the new rules moving through the Nuclear Regulatory Commission, the advanced reactors moving from design to deployment, the companies going public and the utilities merging, and the executive orders and acts of Congress reshaping how the country builds. We explain not just what happened, but why it matters and how the pieces fit together.

We write for readers who want substance: policymakers, industry professionals, investors, researchers, and anyone trying to follow nuclear energy as it takes on a larger role in the world.

After years on Mailchimp, we’ve moved Nuclear Notes to Substack. For you, not much changes—it still arrives every Thursday in your inbox. But Substack gives the newsletter a permanent home on the web, so past issues are now easy to browse and search.

Nuclear Notes is written by Matthew L. Wald, a longtime energy and nuclear journalist with more than 35 years of experience at The New York Times, with assistance from Spencer Toohill, Chief of Staff for Breakthrough’s Nuclear Energy Innovation team.

Subscribe now

Share Nuclear Notes

An Advanced Reactor Goes Critical

Antares Nuclear beat the symbolic, but real, deadline of July 4 set in President Trump’s Executive Order 14301 of May 2025, and achieved initial criticality in a prototype of its microreactor on June 4 in a demonstration at the Idaho National Laboratory.

Initial criticality, sometimes called zero power criticality, is a key milestone in reactor development. The reactor may generate only a few watts of power, but it is a test that can confirm the geometry of the core and provide data needed for licensing. This is particularly significant as the industry moves beyond the familiar light-water reactors, in which water moderates the speed of the neutrons to improve conditions for fission, and carries the heat away for conversion into electricity. All the models moving towards initial criticality now are of less familiar designs, using inert gas, molten metal, or salt as the working material to carry away the heat so it can do useful work. Some under development are “fast” reactors, meaning that there is no water or other material to slow down the neutrons, and these can fission a wider variety of materials. But all of the ones expecting to achieve initial criticality soon have neutrons that are slowed down.

“Initial criticality” has changed its meaning slightly in the current round of nuclear development. Big reactors were not prototyped the way small ones are being developed today, and initial criticality in the Westinghouse AP1000 was in the first commercial model. The Antares reactor is still a work in progress, and the company anticipates iterative development, with several models built and tested before the final commercial version is ready, with a goal of commercial operation by September 30, 2028.

So, while initial criticality in the power reactors running today was a sign that construction was done and start-up testing was well under way, in the new class of advanced reactors it is a step in prototyping, and just one in a long development process. In big reactors, it was a step toward commercial operation of that particular reactor; now, it’s a step that developers say will lead towards stamping out repeated copies of the same commercial machine.

Previously, initial criticalities were usually part of the NRC licensing process. The initial criticality for Antares and any others that follow in the next few weeks is following a different path, with approval by the Energy Department rather than the Nuclear Regulatory Commission. The latter’s approval would be required for civilian deployment.

NRC approval will not be required for use by Antares’ launch customer, the Defense Department, which wants it for reliable production at military bases. It can also be used in space. It has an output of 200 to 300 kilowatts, according to the Department of Energy, and can run for at least three years without refueling. It uses sodium coolant and high-assay low-enriched uranium (HALEU) in TRISO form, which consists of small kernels of uranium encased in layers of heat-resistant materials, with the fuel itself providing the primary radiation barrier.

It does not resemble large power reactors. Reactivity control is provided by drums made of graphite, which can be turned to help the nuclear reaction by slowing down the neutrons. Drums of boron carbide, which slows the reaction by absorbing neutrons, can also be maneuvered. Controls are automated. But the test apparatus in which criticality was achieved was a long way from a power reactor; it did not have a mechanism for removing heat from the core, or converting it into electricity.

Trump’s goal was at least three new reactors reaching initial criticality by July 4, and the Energy Department has approved the preliminary safety analysis of four: Antares in January of this year, Radiant Industries in February, and Valar Atomics and Aalo Atomics in March.

Valar Atomics, which is developing a high-temperature gas-cooled reactor, reached initial criticality last November in a demonstration at Los Alamos National Laboratory, in a test configuration that closely resembles what it is planning to use in its reactor. It also uses TRISO fuel, and HALEU. Whether this counts towards the goal of three by July 4 is not clear, but it is a milestone in any case.

Radiant’s model is also small, designed to replace diesel generators, especially in places where delivering diesel is hard. It can make electricity, or provide up to 1.9 megawatts of thermal power, for heating or desalinating water.

Aalo’s reactor is larger, 50 megawatts, and intended for data center customers. It uses uranium enriched up to 10 percent and is cooled by helium

Dig Deeper

Plutonium, anyone?

Five companies have now confirmed that they’ve been selected by the Department of Energy as potential recipients of surplus plutonium from the weapons program, for use in their advanced reactors.

The Department itself has had extensive troubles with the chemical processing involved, and has dropped its efforts, but wants the private sector to take on the job. Weapons plutonium is sometimes alloyed with another material, gallium, to stabilize it, but that is undesirable in water-based reactors for technical reasons. And the operators of today’s water-based reactors were not eager to use plutonium because doing so would require applying for a license amendment from the NRC, which can be a long, costly process. And their regular fuel source, low-enriched uranium, is readily available.

In contrast, many of the advanced reactors are not water-based, and their developers would prefer plutonium in the mix, because plutonium produces more neutrons per fission. There are technical obstacles, however. One is that over time, the plutonium breaks down into decay products that are also undesirable, like americium. But SHINE Technologies, of Janesville, Wisconsin, says that it will work with a partner, Zeno Power, to remove americium from the plutonium. It is one of the companies that is in line to receive government surplus plutonium.

There are four other companies that would want plutonium fuel as an option. Exodys Energy is developing an electrochemical technology that it intends to deploy in modular recycling units. Standard Nuclear plans to produce TRISO fuel, which can be used in a variety of designs. The company says it is “reactor agnostic.”

Flibe Energy is developing a liquid fluoride thorium reactor. Thorium is not fissile but it is “fertile,” needing to capture a neutron to convert into uranium-233, which is a reactor fuel. Getting started requires a fuel that is fissile, and plutonium fits well into the company’s plans. An advantage of a thorium cycle is that the reactor has less uranium-238, which, when it captures a neutron, becomes yet more plutonium.

Oklo is developing small fast reactors and would also like the plutonium. “Fuel supply constraints are a key throttle to advanced reactor development,” the co-founder Jacob DeWitte, told World Nuclear News. Oklo plans a $1.7 billion recycling plant in Oak Ridge, Tennessee, to do the work.

These are mostly small start-ups without extensive physical assets, although some are well-funded. The Energy Department authorization will allow them to proceed outside the NRC’s licensing framework for testing and piloting, but they will still face major technical challenges, and security requirements.

Dig Deeper

TMI Restart is Off-Again, On-Again

When Constellation shut its Three Mile Island 1 reactor in September 2019, it quickly ruined some key pieces of equipment to lower its carrying costs during decommissioning. But the longest lead-time item in the restart of the reactor, now called the Crane Clean Energy Center, has been getting permission to re-connect to the grid. The regional grid operator, the PJM Interconnection (for Pennsylvania-Jersey-Maryland) has a queue.

With pressure from the governor of Pennsylvania, Josh Shapiro, PJM moved the plant to the front of the line, but then it moved it back again. Now the Federal Energy Regulatory Commission has stepped in, and ruled that Constellation can re-start the plant by transferring connection rights from a gas-fired plant that it is planning to retire. So the re-start is back on track for 2027.

And, on Tuesday, the NRC ruled that re-starting the plant would not require a full Environmental Impact Statement.

Dig Deeper

Another Weak Link in the Supply Chain?

A survey of 35 nuclear academic programs by the Oak Ridge Institute for Science and Education, updated in 2024, found that nuclear engineering programs awarded 27 percent fewer bachelors degrees in 2022 than in the years 2016 to 2019, and that graduate enrollment was also down slightly. That probably portends a drop in graduate education too.

Dig Deeper

Even More Vertical Integration

Oklo is already unusual for planning to sell heat and electricity, not reactors, but it has taken another step towards vertical integration: it has bought a company that can make fuel and components for nuclear reactors.

Dig Deeper

Addressing Fusion’s Proliferation Potential

Two good fuels for nuclear weapons, plutonium-239 and uranium-233, are made by capturing stray neutrons released in the chain reaction of a fission reactor, and transmuting readily-available atoms that are able to absorb a neutron (fertile), but not able to split (fissile) until they do so.

Fusion reactors, though, produce neutrons in abundance, and could be used to surreptitiously produce weapons fuel. Now, scientists at Princeton and Virginia Tech have proposed a novel way to detect such production, with a machine that senses anti-neutrinos.

Dig Deeper

See a story we missed or one that you think should be included, let us know in the comments or message us!

Subscribe now

Note: An earlier version of this post stated incorrectly that Aalo was planning to use TRISO fuel.