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.
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.
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.
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.
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.
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.
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.’
Thanks for reading!
Good to hear Germany is waking up. About time. Hope they follow through.