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.
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.
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.
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.
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.
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.
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