Spurred by a suite of executive orders and investments from the federal government, new nuclear reactors are coming soon. Or the announcements are at least.
The advanced nuclear sector has found itself in the spotlight as companies race to acquire licenses and permits aimed at achieving “criticality.” But what do these milestones signify? And is hitting the deadlines even feasible?
In this episode, Shayle talks to Katy Huff, former assistant secretary for nuclear energy at the Department of Energy and current associate professor at the University of Illinois. They unpack the wave of new nuclear announcements, the realities of navigating an arcane regulatory gauntlet, and what Katy considers a realistic timeline for new nuclear deployment.
Shayle and Katy cover topics like:
- The NRC’s “murky” pre-application process
- The differences between various licensing pathways
- Why Katy views the DOE’s goal to have three reactors reach criticality by July 4th as “an extremely aggressive milestone”
- Upcoming revised guidance on nuclear radiation dose rates
- The challenges facing the DOE amidst a staff shortage
- Katy’s assessment of a feasible timeline for getting new reactors operational
- Why Katy doesn’t think microreactors are economically scalable…yet
Resources
- Catalyst: The US nuclear groundswell
- Open Circuit: Inside Meta’s massive nuclear push
- Latitude Media: The self-inflicted hurdles facing Trump’s nuclear orders
- Latitude Media: The Department of Energy’s 2026 playbook
- Latitude Media: Trump’s Westinghouse nuclear deal comes with unresolved questions
Credits: Hosted by Shayle Kann. Produced and edited by Max Savage Levenson. Original music and engineering by Sean Marquand. Stephen Lacey is our executive editor.
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Transcript
Shayle Kann: I am Shayle Kann and this is Catalyst. I lead the early-stage venture strategy at Energy Impact Partners. New nuclear reactors are coming, with a host of private companies advancing designs and pushing them through the Nuclear Regulatory Commission (NRC). Most are aiming for commercialization in the next couple of years or at least this decade, and the Department of Energy (DOE) seems to be on board. In fact, the DOE launched a program last year picking 11 early-stage companies and challenging at least three of them to reach criticality by July 4th of this year, 2026. While momentum is building through various technical and regulatory milestones, it is difficult for those not steeped in the nuclear world to separate signal from noise. To help untangle this, I brought on Katy Huff, the former Assistant Secretary for Nuclear Energy at the DOE and current associate professor at the University of Illinois.
Katy Huff: Fundamentally, the process starts with a design, a site, and pre-application engagement with the NRC. You must perform safety analysis and put together a site report and a safety analysis report for the reactor design. You also have to develop plans for operations, operator training, and safety protocols for specific accidents. These documents go to the NRC, which ideally issues a construction permit and then an operating license, though a pathway exists to do those in parallel. This involves public meetings, hearings, and a significant amount of back-and-forth through technical white papers and reports. There is also a financial plan that the NRC reviews. Generally, there are three pathways: Part 50, which separates the construction permit and operating license; Part 52, which combines them; and the newer Part 53 for advanced reactors, which no one is really using yet. This process always takes years.
Shayle Kann: The process seems more iterative and collaborative than one might imagine, rather than just filing an application and waiting for a “thumbs up”. Companies often announce productive design review sessions with the NRC, but it is hard to tell if that indicates real progress or if rejections happen early in the ground before a formal construction permit is submitted.
Katy Huff: While engagement indicates that the company is active and the NRC is informed, the NRC does not issue official decisions during pre-application activities. Companies must submit a letter of intent and billing information so the NRC can charge for their time. You also put together a regulatory engagement plan and hold public kickoff meetings and readiness assessments before submitting an application. Once submitted, the NRC decides whether to accept it for review. Rejections do happen at the acceptance stage, often because the application lacks the technical depth required for the review, sometimes years after pre-application activities began.
A design certification is a separate step that is hyper-focused on certifying the reactor itself as safe, independent of the site. This allows subsequent license applications to focus only on site-specific questions. For example, the NRC denied Oklo’s combined license application, which attempted to do the operating license and construction permit in parallel without a separate design certification. It was rejected primarily because it had information gaps regarding potential accidents and the classification of safety systems.
Shayle Kann: In terms of the timeline, it seems intuitive that the design certification would be the hardest and longest step, followed by the construction permit and then the operating license.
Katy Huff: Statistics vary per reactor, so it is hard to say definitively. However, environmental reviews under NEPA (National Environmental Policy Act) often happen in parallel and can be the “long pole in the tent”. These environmental impact assessments can rival safety assessments in both length and review time, regardless of the reactor design itself.
Currently, the NRC is under great pressure to move faster, but they are facing numerous deadlines and have fewer staff than before this administration began. While the bipartisan Advance Act has provided ways to accelerate licensing—such as sharing international information or streamlining the use of former fossil fuel sites—external requirements and leadership vacancies have slowed things down. Executive orders issued in February and May of last year aimed to align independent regulatory commissions, including the NRC, more closely with White House decisions. This includes potential renovations to how the commission thinks about dose rates, with a deadline for rulemaking guidance on February 23rd.
Despite these constraints, some applications for reactors like those from X-Energy and Kairos are progressing quickly with recent positive license announcements. For companies like TerraPower and others, you should look for construction permit approvals as the next big milestone. Kairos has already received construction permits for test reactors and is moving toward final safety evaluations.
Shayle Kann: The DOE pilot program aims for three reactors to reach criticality by July 4th of this year. How significant is that milestone?
Katy Huff: It depends on the type of criticality. A “zero power criticality test” can be achieved without making real engineering progress on fuel or design; it simply checks if you can multiply neutrons. For example, Valor Atomics reached criticality at Los Alamos, but it was a cold zero power test that did not take the fuel up to actual power densities. I want to see “hot full power” criticality. Historically, the median time from pouring concrete to hot full power criticality is about two years. Most reactors are not on pace for the July 4th milestone because it is extremely aggressive and perhaps unfair to an industry that builds high-precision machines. The DOE was not prescriptive about whether they meant zero power or full power criticality, which might allow companies to declare victory even if the milestone is less meaningful.
Shayle Kann: Regarding other milestones, Radiant claims their Kaleido reactor will be the first to achieve a “fueled test” in over 50 years by 2026. How does that relate to the NRC pathway for micro-reactors?
Katy Huff: A fueled test is the kind of hot full power test I mentioned, where you put fuel in the vessel, close it, and turn it on to see if modeling matches reality. Currently, the licensing options for micro-reactors are the same as for large reactors. While Part 53 was intended to support advanced reactors, many still choose Part 50 or 52 with specific waivers. The NRC has done well looking into unique micro-reactor issues, such as determining that emergency planning zones might not need to extend beyond the site fence line.
In terms of signals, a letter of intent is the lightest indicator. Submitting a construction permit application or a safety analysis report is a serious step. The strongest signs are when the NRC approves a construction permit, design certification, or operating license. On the utility side, a partnership for an early site permit application is much more serious than a simple Memorandum of Understanding (MOU). For micro-reactors specifically, I am looking for a reactor factory. These do not make economic sense until they are built in a factory. Companies like Holtec, which has long built nuclear fuel casks, have an advantage in fabrication.
Shayle Kann: How do these companies contend with spent nuclear fuel and waste?
Katy Huff: The NRC requires “waste confidence,” meaning there must be a plan for the waste before a reactor can operate. Since there is no final repository like Yucca Mountain, companies must include plans for interim on-site management until the federal government takes ownership. This usually involves cooling fuel in pools and then moving it to dry cask storage. Some companies may eventually include active recycling facilities.
Shayle Kann: When will we see the first new reactor operating on the grid?
Katy Huff: Several companies are neck and neck for construction permit decisions in late 2026 or 2027. TerraPower, X-Energy, and Kairos are close, and the University of Illinois is also pursuing a research and test micro-reactor on a similar timeline. I would be surprised if we do not see real new advanced reactor electrons on the grid by 2032. It will likely start with one reactor, followed shortly by others, though construction delays could reduce investor confidence and slow the whole process.
Shayle Kann: All right, Katie. This was very informative and I feel substantially better at, uh, being able to interpret all the announcements that I see in this space. So thank you so much for the time.
Katy Huff: Yeah, thanks for having me.
