Nuclear for AI data centres: regulatory steps, timelines, risks

New nuclear power for AI data centres has to clear several gates in the United States: a site decision, an environmental review, a construction permit or combined licence, a mandatory hearing, an operating licence, a fuel supply and a grid connection. The three most recent new reactor construction approvals took between about 14 and 24 months, depending on where the clock starts. Policy changes since 2024 aim to shorten that, but building and fuelling a plant still take years after any approval.

This post explains what each regulatory step involves, recomputes recent review times from dates published by the Nuclear Regulatory Commission (NRC), the companies and World Nuclear News, sets out what the 2024 ADVANCE Act and the May 2025 executive orders changed, and lists the main risks. Check primary documents before relying on any figure. Nothing here is investment advice or a legal opinion.

Key numbers at a glance

• Executive Order 14300, signed 23 May 2025: no more than 18 months for a final decision on an application to construct and operate a new reactor, and no more than 1 year for continued operation of an existing reactor (White House text, accessed 19 October 2026).
• Same order: proposed rules within 9 months and final rules within 18 months of the order, which points to late November 2026 for final rules (White House text).
• Same order: US nuclear capacity from about 100 GW in 2024 to 400 GW by 2050 (White House text).
• Executive Order 14302, 23 May 2025: 5 GW of power uprates at existing reactors and 10 new large reactors with complete designs under construction by 2030 (White House text).
• Executive Order 14301, 23 May 2025: at least three Department of Energy pilot reactors, with a goal of criticality in each by 4 July 2026 (White House text).
• ADVANCE Act, Public Law 118-67, approved 9 July 2024: caps the hourly fee rate for advanced reactor applicants from 1 October 2025 and sets a 25 month decision deadline for qualifying combined licence applications (govinfo.gov text).
• TerraPower Kemmerer Unit 1: application March 2024, review began May 2024, construction permit announced 4 March 2026, about 23 to 24 months from filing; the NRC says its technical review took less than 18 months (NRC release 26-028, 4 March 2026).
• Kairos Hermes 2: application July 2023, permits approved November 2024, about 16 months (World Nuclear News, 21 November 2024).
• TVA Clinch River BWRX-300: application completed late May 2025, review began July 2025, permit announced 29 September 2026; the NRC said the review took 14 months, four months ahead of schedule (DOE, 10 July 2025; World Nuclear News, 30 September 2026).
• NuScale US460 standard design approval: accepted July 2023, final safety evaluation 28 May 2025, about 22 months (POWER magazine, 5 June 2025).
• Early site permit validity: not less than 10 nor more than 20 years from issue (10 CFR 52.26).
• Darlington, Canada: licence to construct the first BWRX-300 issued by the Canadian Nuclear Safety Commission in April 2025, in-service target 2030 (World Nuclear News, 8 May 2025).
• HALEU: the Department of Energy says high assay low enriched uranium "is not currently available from domestic suppliers" (DOE HALEU Availability Program page, accessed 19 October 2026).
• Workforce: reaching about 200 GW of advanced nuclear by 2050 would need an additional 375,000 workers, per the Department of Energy as cited by Google (14 October 2024).

Three licensing routes: Part 50, Part 52 and Part 53

The NRC regulates commercial reactors under Title 10 of the Code of Federal Regulations. A developer chooses a route before filing, and the choice shapes the whole schedule.

Part 50, the two step route. The applicant first seeks a construction permit, then applies separately for an operating licence once the design is mature and construction is under way. Kairos describes its Hermes 2 project as following this "two-step 10 CFR Part 50 process", and the NRC's 4 March 2026 release on Kemmerer says TerraPower's subsidiary must file a separate operating licence application before the plant can run. The advantage is that building can start before every operating detail is settled. The cost is a second full review later.

Part 52, the one step route. Part 52 bundles approvals so that design and site questions can be settled in advance. Its subparts cover early site permits, standard design certifications, combined licences, standard design approvals and manufacturing licences (10 CFR Part 52, Cornell LII text). A combined licence authorises both construction and operation. An early site permit settles whether a location is acceptable before a specific plant is chosen, and it is valid for not less than 10 nor more than 20 years (10 CFR 52.26). TVA's Clinch River project builds on such a permit, which the Department of Energy described in July 2025 as "the nation's first and only" early site permit for a small modular reactor.

A standard design approval is lighter than a certification. POWER magazine, reporting on NuScale's US460 approval in June 2025, describes it as a staff level approval of a design that later applicants can reference, but which lacks the legal finality of a design certification, so issues can be reopened in later licensing steps. It does not authorise anyone to build.

Part 53, the technology inclusive route. For decades the rules were written around large light water reactors. Part 53 is an alternative framework that is meant to work for any reactor technology, size or end use. The NRC's Part 53 page, last updated 29 April 2026, describes it as a final rule and links to the Federal Register notice at 91 FR 15696. Among the features the NRC lists:

• risk insights from probabilistic risk assessment or other systematic risk evaluations, based largely on the Department of Energy cost shared Licensing Modernization Project method;
• alternative siting criteria that can allow a plant in or near a densely populated centre of more than about 25,000 residents, based on an assessment of societal risk against societal benefit;
• loading fuel into a manufactured reactor at the factory before it is shipped;
• remote operation and reduced staffing for suitable designs;
• automatic load following to match demand;
• new alternative frameworks for fitness for duty in 10 CFR Part 26 and physical security in 10 CFR Part 73.

The siting and load following provisions matter for data centres in particular, because both bear on whether a reactor can sit close to a large load and follow it. No project has yet completed a licence under Part 53, so its real effect on schedules is untested. The same NRC page lists a separate proposed Part 57 for microreactors and other reactors with comparable risk profiles.

What each step involves

Pre-application. Developers usually talk to the NRC for years before filing. Kairos credits pre-application engagement dating to 2018 for the speed of its Hermes 2 review.

Acceptance and docketing. The NRC first checks whether an application is complete enough to review. Only then does the formal clock start. For Kemmerer the application went in during March 2024 and formal review began in May 2024 (NRC, 4 March 2026). For Clinch River, TVA completed its filing in late May 2025 (DOE, 10 July 2025) and the NRC began formal review in July 2025 (World Nuclear News).

Safety review. NRC staff write a safety evaluation, the technical finding that the design and site meet the rules. For Kemmerer the safety evaluation was issued in December 2025. For Hermes 2 the final safety evaluation came in July 2024 (World Nuclear News, 21 November 2024).

Environmental review under NEPA. Under 10 CFR 51.20, an environmental impact statement is required before issuing a construction permit, an early site permit, a combined licence, or a full power operating licence for a power reactor or testing facility. The Kemmerer final environmental impact statement was issued in October 2025, five months before the permit. Hermes 2, a smaller test facility, received a final environmental assessment in August 2024. Executive Order 14300 directs the NRC to revise its NEPA rules to reflect the 2023 amendments to that statute, and section 506 of the ADVANCE Act required the NRC to report on environmental review efficiency within 180 days of enactment.

Mandatory hearing. The Atomic Energy Act requires the Commission to "hold a hearing after thirty days' notice and publication once in the Federal Register" on each construction permit application (42 U.S.C. 2239). This happens even if nobody objects. For Kemmerer the NRC described a "streamlined mandatory hearing process" before the Commission authorised staff to issue the permit. For Clinch River a public hearing was held in Oak Ridge in August, before the September 2026 permit (World Nuclear News, 30 September 2026). The executive order lists streamlined public hearings among the topics for new rules.

Operating licence. After construction, a Part 50 plant needs a second licence to load fuel and operate. None of the advanced plants discussed here holds one yet. In Canada, Ontario Power Generation applied in March 2026 for a licence to operate its first Darlington BWRX-300, and that application is under review (GE Vernova, 29 September 2026).

How long recent approvals took

The durations below are recomputed from published month level dates, so each is approximate to within a month. Where the NRC itself stated a duration, that figure is given too.

• TerraPower Kemmerer Unit 1. Filed March 2024, formal review from May 2024, permit announced 4 March 2026 (NRC release 26-028). That is about 23 to 24 months from filing and about 22 months from the start of formal review. The NRC says staff finished the technical review in less than 18 months. World Nuclear News reported an initial 27 month schedule.
• Kairos Hermes 2. Filed July 2023, permits approved in November 2024 (World Nuclear News, 21 November 2024; Kairos, November 2024). That is about 16 months. Then NRC chair Christopher Hanson said the permits were issued "in less than 18 months", and Kairos said the staff review took "just over one year".
• TVA Clinch River BWRX-300. Filing completed late May 2025, formal review from July 2025, permit announced 29 September 2026 (DOE; World Nuclear News; GE Vernova). That is about 16 months from filing and about 14 months from the start of formal review, which matches the NRC's own 14 month figure. GE Vernova dates the first part of TVA's submission to April 2025, which would make the gap from first filing about 17 months. The NRC had planned 17 months when it accepted the application (World Nuclear News, 11 July 2025).
• NuScale US460 design approval. Accepted July 2023, final safety evaluation 28 May 2025 (POWER magazine). That is about 22 months. This is a design approval, not a permit to build.

So recent reviews run roughly 14 to 24 months. The answer moves by several months depending on whether the count starts at filing, at docketing or at the start of the technical review. Executive Order 14300 says its deadlines run from the "first required regulatory step", a term the order does not define, so it is not yet clear how these cases would be scored against its 18 month limit. All of these were first of a kind reviews, which usually take longest. Project by project status for small reactors, including which designs buyers have backed, is covered in a related post, Small modular reactors for AI data centres: designs and timelines.

A permit is not a power plant. TerraPower began non nuclear construction in June 2024 and expects the plant to be complete in 2030 (World Nuclear News, 5 March 2026). TVA had not announced a construction start date when its permit arrived (World Nuclear News, 30 September 2026). In Canada, OPG received its licence to construct in April 2025 and targets 2030 for the first unit to enter service (World Nuclear News, 8 May 2025). In each case, construction and commissioning take longer than the licensing review.

What the 2025 executive orders changed

Executive Order 14300, on reform of the NRC, sets the clock. It asks for fixed deadlines of no more than 18 months for a new reactor and no more than one year for continued operation of an existing reactor, and says those deadlines "shall be enforced by fixed caps on the NRC's recovery of hourly fees." It calls for a wholesale revision of NRC regulations covering, among other topics, radiation limits, NEPA compliance, an expedited path for designs already tested by the Departments of Defense or Energy, high volume licensing for microreactors and modular reactors, limits on design changes after construction starts, licence renewal periods and streamlined hearings. It tells the NRC to reconsider its reliance on the linear no threshold model for radiation exposure. It also directs a reorganisation with reductions in force, a team of at least 20 officials to draft the rules, and a cut in the Advisory Committee on Reactor Safeguards to its statutory minimum.

Executive Order 14302, on the industrial base, sets the targets: 5 GW of uprates, 10 large reactors under construction by 2030, and a Department of Energy plan to expand enrichment for low enriched, high enriched and high assay low enriched uranium. A power uprate is an approved change that lets an existing reactor produce more electricity. The order also tells the department's Loan Programs Office to prioritise nuclear projects, including restarts and uprates. Restarts follow a shorter regulatory path because the plant already exists, as explained in How a US nuclear plant restart works, from licence to grid.

Executive Order 14301 creates a separate track. It says certain advanced reactors under Department of Energy control that do not produce commercial power fall within the department's jurisdiction, and it orders a pilot programme for reactor construction and operation outside the national laboratories. This route does not license a commercial power plant for a data centre, but Executive Order 14300 asks the NRC to create an expedited path for designs already tested by the Departments of Defense or Energy.

These orders are policy direction. Their effect will show up in the final rule text and in licensing decisions made under it. Changes such as reconsidering the linear no threshold model and shrinking an independent advisory committee touch long standing safety conventions, and public comment on the proposed rules is where those trade offs are argued.

The ADVANCE Act and NRC fees

The ADVANCE Act came first. It is Division B of Public Law 118-67, approved on 9 July 2024 (govinfo.gov). Several sections bear directly on new reactors for large loads:

• Fees. Section 201 caps the hourly rate charged to advanced reactor applicants and pre-applicants so that it may not exceed the hourly rate for mission direct program salaries and benefits, from 1 October 2025. NRC reviews are paid for largely through hourly fees, so this lowers the cost of a long review rather than shortening it.
• Brownfield and retired fossil sites. Section 206 covers licensing at brownfield and retired fossil fuel sites. Kemmerer, which the NRC describes as near an existing coal plant, is an example of this kind of site.
• Combined licence deadline. Section 207 requires a final decision on a qualifying combined licence application no later than 25 months after it is accepted for docketing.
• Microreactors. Section 208 requires risk informed licensing strategies and guidance for microreactors within 18 months of enactment.
• Mission statement. Section 501 requires the NRC to update its mission so that licensing is efficient and "does not unnecessarily limit" civilian use of nuclear energy.

Fuel licensing and supply

Fuel is regulated separately from the reactor. Enrichment and fuel fabrication plants need their own NRC licences, and many advanced designs need high assay low enriched uranium, or HALEU, enriched above the level used in most operating reactors. The Department of Energy says "most advanced reactor designs require HALEU" and that it "is not currently available from domestic suppliers", warning that supply gaps could delay deployment (DOE HALEU Availability Program page, accessed 19 October 2026).

The department allocates HALEU from its own stocks in rounds. Its allocation page lists conditional selections on 9 April 2025 (TRISO-X, Kairos Power, Radiant, Westinghouse and TerraPower), on 26 August 2025 (Antares, Standard Nuclear, and Abilene Christian University with Natura Resources) and on 23 July 2026 (NASA and Radiant). It does not publish quantities. A reactor permit therefore does not settle whether fuel will be ready on the day the plant is.

Beyond the NRC: grid, states and Canada

An NRC licence does not connect a plant to anything. A new plant still has to be studied by its regional grid operator, and queues are long. Requests in those queues often overstate what will be built, as explained in How much electricity will AI data centres need? Forecasts compared. State approvals, such as utility commission decisions on cost recovery and state siting rules, vary by state and sit outside the federal process described here. Contract structures, including plants that serve a neighbouring data centre directly, are covered in Nuclear power for AI data centres: restarts, uprates, new reactors.

Canada offers a comparison under a different regulator. The Canadian Nuclear Safety Commission issued OPG a licence to construct the first BWRX-300 at Darlington in April 2025, the first of four units planned there, with a project budget of CAD 20.9 billion reported by World Nuclear News on 8 May 2025. OPG applied for a licence to operate in March 2026. The Darlington and Clinch River units use the same design, so Canadian results will be watched closely in the United States.

The risks, in plain terms

Cost. First of a kind plants carry cost risk that a permit does not resolve. When TVA received its permit, it said it was still negotiating cost sharing with industry partners, and its chief executive spoke of "ensuring the people of the Valley do not shoulder the costs of first-of-a-kind technology" (TDWorld, 30 September 2026). A technology company with a long contract takes some of that risk. A utility with ratepayers takes more.

Schedule. The review is only one segment. Kemmerer's permit came about two years after filing, and the plant's completion target is 2030 (World Nuclear News, 5 March 2026). Any slip in construction, fuel or grid work moves the date a data centre can count on.

Rule change risk. The executive orders call for new rules on a tight timetable, Part 53 is new, and Part 57 is still a proposal. Applicants filing now must decide whether to use established rules or wait for new ones, and rules can face legal challenge.

Fuel. The Department of Energy's own statement that HALEU is not available from domestic suppliers is the plainest summary of this risk.

People. The 375,000 worker estimate shows the scale. Welders, operators, engineers and inspectors are needed in the same years across many projects, and the NRC itself is being reorganised while its workload grows.

Safety and public trust. Faster reviews, a smaller advisory committee and a revised radiation model raise questions about oversight. How those questions are answered in final rules will shape local support for sites near large data centre campuses.

Cybersecurity. Digital controls and supplier software are part of any new plant. Part 53 includes a new performance based alternative security framework in 10 CFR Part 73, and the existing cyber rule for operating plants is explained in NRC 73.54, the nuclear cyber security plan, explained.

Counterparty and demand risk. Long power contracts depend on data centres actually being built and used. Letters of intent do not bind anyone until a signed contract says so.

What is firm and what is uncertain

Firm:

• The NRC has issued construction permits for Kemmerer (March 2026) and Clinch River (September 2026), and Kairos received Hermes 2 permits in November 2024.
• Recent reviews took roughly 14 to 24 months, depending on where the clock starts.
• The May 2025 executive orders and the 2024 ADVANCE Act set the deadlines, fee caps and targets quoted above, as their texts state.
• The NRC lists Part 53 as a final rule.

Uncertain:

• Whether final rules under Executive Order 14300 arrive by late November 2026, and how the 18 month clock will be counted.
• How quickly the first Part 53 applications move through review.
• Whether construction at Kemmerer, Clinch River and Darlington finishes on schedule and on budget.
• HALEU supply for designs that need it.
• Whether any new reactor, as opposed to a restart or uprate, delivers power to a data centre before 2030.

What to watch next

• NRC final rules under Executive Order 14300, due about 18 months after 23 May 2025.
• The first applications filed under Part 53 and the progress of the proposed Part 57 for microreactors.
• Operating licence applications for Kemmerer and Hermes 2, and the CNSC decision on OPG's Darlington licence to operate.
• Whether TVA announces a construction start and a cost sharing agreement for Clinch River.
• Further Department of Energy HALEU allocation rounds and any published quantities.
• Department of Energy announcements on the Executive Order 14301 pilot reactors and their 4 July 2026 criticality goal.

Quick check

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Sources

• Ordering the Reform of the Nuclear Regulatory Commission (Executive Order 14300), The White House, 23 May 2025, accessed 19 October 2026.
• Reinvigorating the Nuclear Industrial Base (Executive Order 14302), The White House, 23 May 2025, accessed 19 October 2026.
• Reforming Nuclear Reactor Testing at the Department of Energy (Executive Order 14301), The White House, 23 May 2025, accessed 19 October 2026.
• Public Law 118-67, including the ADVANCE Act of 2024, US Government Publishing Office, approved 9 July 2024, accessed 19 October 2026.
• NRC Issues First Commercial Reactor Construction Approval in 10 Years For TerraPower in Wyoming (No. 26-028), US Nuclear Regulatory Commission, 4 March 2026.
• Part 53, Risk-Informed, Technology-Inclusive Regulatory Framework for Commercial Nuclear Plants (Internet Archive copy of the NRC page), US Nuclear Regulatory Commission, page updated 29 April 2026, accessed 19 October 2026.
• Advanced Reactors (Internet Archive copy of the NRC page), US Nuclear Regulatory Commission, page updated 13 August 2026, accessed 19 October 2026.
• 10 CFR Part 52, Licenses, Certifications, and Approvals for Nuclear Power Plants, Cornell Legal Information Institute, accessed 19 October 2026.
• 10 CFR 52.26, Duration of permit, Cornell Legal Information Institute, accessed 19 October 2026.
• 10 CFR 51.20, Criteria for and identification of licensing and regulatory actions requiring environmental impact statements, Cornell Legal Information Institute, accessed 19 October 2026.
• 42 U.S.C. 2239, Hearings and judicial review, Cornell Legal Information Institute, accessed 19 October 2026.
• NRC issues construction permit for first Natrium plant, World Nuclear News, 5 March 2026.
• Hermes 2 construction permits approved by US Nuclear Regulatory Commission, World Nuclear News, 21 November 2024.
• Nuclear Regulatory Commission Approves Construction Permits for Hermes 2 Demonstration Plant, Kairos Power, November 2024, accessed 19 October 2026.
• NRC Dockets Construction Permit Application for TVA Small Modular Reactor, US Department of Energy, 10 July 2025.
• Clinch River application accepted for review, World Nuclear News, 11 July 2025.
• First construction permit issued for BWRX-300 SMR in the US, World Nuclear News, 30 September 2026.
• NRC issues first US construction permit for BWRX-300 small modular reactor at TVA Clinch River, GE Vernova, 29 September 2026.
• TVA Receives Construction Permit for Clinch River BWRX-300 Advanced Nuclear Reactor, T&D World, 30 September 2026.
• NuScale's 77-MWe SMR clears NRC review, sets stage for first firm order, POWER magazine, 5 June 2025.
• OPG gets go-ahead to build first SMR in Canada, World Nuclear News, 8 May 2025.
• HALEU Availability Program, US Department of Energy, accessed 19 October 2026.
• US Department of Energy HALEU Allocation Process, US Department of Energy, accessed 19 October 2026.
• Google and Kairos Power nuclear energy agreement, Google, 14 October 2024.

Last reviewed: 19 October 2026.