Regulation
Licensing
30 milestones.
| Organisation | Stage | Date | Regulator | Anchor | Source |
|---|---|---|---|---|---|
| Abilene Christian University | Application submitted achieved Molten Salt Research Reactor construction permit application submitted | 2022-08-12 | US Nuclear Regulatory Commission | Docket 50-610 · ADAMS ML22227A201 | Abilene Christian University; construction permit application acceptance for docketing (FR Doc 2022-25890) |
| Holtec International | Application submitted achieved Pioneer Units 1 and 2 (SMR-300): Part 1 of phased construction permit application submitted | 2025-12-31 | US Nuclear Regulatory Commission | Dockets 50-616, 50-617 · ADAMS ML25365A983 (Part 1 package) | SMR, LLC; Pioneer Units 1 and 2; Phased Construction Permit Application-Limited Work Authorization (FR Doc 2026-03943) |
| Oklo | Application submitted achieved Aurora custom combined licence application submitted (Idaho National Laboratory) | 2020-03-11 | US Nuclear Regulatory Commission | Docket 52-049 · ADAMS ML20075A001 | Oklo Power LLC; Oklo Aurora Combined License Application Idaho National Laboratory — denial (87 FR 1441) |
| Tennessee Valley Authority | Application submitted achieved Clinch River Unit 1 (BWRX-300) construction permit application submitted | 2025-04-28 | US Nuclear Regulatory Commission | Docket 50-615 · ADAMS ML25118A209 (NNP-25-003), ML25140A063 (NNP-25-004) | Tennessee Valley Authority; Clinch River Nuclear Site, Unit 1; Construction Permit Application — acceptance for docketing |
| TerraPower | Application submitted achieved Construction permit application submitted for Kemmerer Power Station Unit 1 (Natrium), Wyoming | 2024-03-28 | US Nuclear Regulatory Commission | Docket 50-613 · ADAMS ML24088A059 (application) | US SFR Owner, LLC; Kemmerer Power Station, Unit 1; Construction Permit Application — acceptance for docketing |
| X-energy | Application submitted achieved Construction permit application submitted for Long Mott (Dow Seadrift) | 2025-03-31 | US Nuclear Regulatory Commission | Docket 50-614 · ADAMS ML25090A057 (application package) | Long Mott Energy, LLC; Long Mott Generating Station; Construction Permit Application — acceptance for docketing |
| Abilene Christian University | Accepted for review achieved Molten Salt Research Reactor construction permit application accepted for docketing | 2022-11-18 | US Nuclear Regulatory Commission | Docket 50-610 · ADAMS ML22313A097 (acceptance letter) | Abilene Christian University; construction permit application acceptance for docketing (FR Doc 2022-25890) |
| Holtec International | Accepted for review achieved Pioneer Units 1 and 2: Part 1 of phased construction permit application accepted for docketing | 2026-02-13 | US Nuclear Regulatory Commission | Dockets 50-616, 50-617 · ADAMS ML26041A223 (acceptance letter) | SMR, LLC; Pioneer Units 1 and 2; Phased Construction Permit Application-Limited Work Authorization (FR Doc 2026-03943) |
| Rolls-Royce SMR | Accepted for review achieved UK Generic Design Assessment begun (Step 1) | 2022-04 | Office for Nuclear Regulation | no anchor | Step 1 GDA statement for the Rolls-Royce SMR |
| Tennessee Valley Authority | Accepted for review achieved Clinch River Unit 1 (BWRX-300) construction permit application accepted for docketing | 2025-07-09 | US Nuclear Regulatory Commission | Docket 50-615 · ADAMS ML25182A151 (acceptance letter) | Tennessee Valley Authority; Clinch River Nuclear Site, Unit 1; Construction Permit Application — acceptance for docketing |
| TerraPower | Accepted for review achieved Kemmerer Unit 1 construction permit application accepted for docketing | 2024-05-21 | US Nuclear Regulatory Commission | Docket 50-613 · ADAMS ML24135A109 (acceptance letter) | US SFR Owner, LLC; Kemmerer Power Station, Unit 1; Construction Permit Application — acceptance for docketing |
| X-energy | Accepted for review achieved Long Mott construction permit application accepted for docketing | 2025-05-12 | US Nuclear Regulatory Commission | Docket 50-614 · ADAMS ML25115A247 (acceptance letter) | Long Mott Energy, LLC; Long Mott Generating Station; Construction Permit Application — acceptance for docketing |
| NuScale Power | Design approval or certification achieved NRC standard design approval for the NuScale US600 design (50 MWe modules) | 2020-09-11 | US Nuclear Regulatory Commission | Docket 52-048 · ADAMS ML20247J564 | NuScale Power, LLC; NuScale Small Modular Reactor — standard design approval; issuance |
| NuScale Power | Design approval or certification achieved NRC design certification of the NuScale US600 design (10 CFR Part 52, Appendix G) | 2023-02-21 | US Nuclear Regulatory Commission | 10 CFR Part 52 App. G · Docket 52-048 · 88 FR 3287 | NuScale Small Modular Reactor Design Certification — final rule (88 FR 3287) |
| NuScale Power | Design approval or certification achieved NRC standard design approval for the NuScale US460 design | 2025-05-29 | US Nuclear Regulatory Commission | Docket 52-050 · ADAMS ML25129A004 (SDA), ML25086A073 (FSER) | NuScale Power, LLC; NuScale US460 Small Modular Reactor; Standard Design Approval |
| Rolls-Royce SMR | Design approval or certification target UK Generic Design Assessment completion (Design Acceptance Confirmation) — not yet issued Downgraded from a claimed design approval: ONR has NOT issued a Design Acceptance Confirmation. As checked 2026-09-22, ONR lists the assessment as ongoing in Step 3. ONR's Step 1 statement (3 April 2023) expected completion in August 2026; that date has passed with no DAC published on the ONR page. | 2026-08 | Office for Nuclear Regulation | no anchor | Rolls-Royce SMR — Generic Design Assessment |
| Abilene Christian University | Construction permit issued achieved NRC construction permit CPRR-124 issued for the Molten Salt Research Reactor | 2024-09-16 | US Nuclear Regulatory Commission | Construction Permit CPRR-124 · Docket 50-610 | Abilene Christian University; Molten Salt Research Reactor; Construction Permit (FR Doc 2024-21468) |
| Kairos Power | Construction permit issued achieved NRC construction permit issued for Hermes test reactor | 2023-12-14 | US Nuclear Regulatory Commission | Construction Permit CPTR-6 · Docket 50-7513 · ADAMS ML23338A258 | Hermes – Kairos Application |
| Kairos Power | Construction permit issued achieved NRC construction permits issued for Hermes 2 test reactor facility (two units) | 2024-11-21 | US Nuclear Regulatory Commission | Construction Permits CPTR-7 (Docket 50-611) and CPTR-8 (Docket 50-612) · ADAMS ML24324A021, ML24324A022 | Kairos Power LLC; Hermes 2 Test Reactor Facility; Construction Permits |
| Ontario Power Generation | Construction permit issued achieved CNSC licence to construct one BWRX-300 at the Darlington New Nuclear Project | 2025-04-04 | Canadian Nuclear Safety Commission | CNSC licence PRCL 32.00/2035 | Decision by the Commission to authorize Ontario Power Generation Inc. to construct 1 BWRX-300 reactor at the Darlington New Nuclear Project site |
| TerraPower | Construction permit issued achieved NRC construction permit CPAR-1 issued for Kemmerer Power Station Unit 1 (Natrium) | 2026-03-09 | US Nuclear Regulatory Commission | Construction Permit CPAR-1 · Docket 50-613 · ADAMS ML26034B247 | US SFR Owner, LLC; Kemmerer Power Station, Unit 1; Construction Permit and Record of Decision |
| Kairos Power | Construction start achieved Hermes test reactor: safety-related construction begins | 2025-05 | US Nuclear Regulatory Commission | Docket 50-7513 · NRC EA/FONSI, FR Doc 2026-07700 (91 FR, 2026-04-21) · ADAMS ML26083A275 (request) | Kairos Power LLC; Hermes Test Reactor; Environmental Assessment and Finding of No Significant Impact (91 FR, FR Doc 2026-07700) |
| TerraPower | Construction start claimed Kemmerer Unit 1: nuclear construction begins (reported) Aggregator source only. No regulator anchor: the construction permit (CPAR-1, 2026-03-09) is anchored separately; this start date is not. Non-nuclear site work began in June 2024. | 2026-04-23 | — | no anchor | Kemmerer Power Station - Wikipedia |
| Holtec International | Operating licence issued achieved Palisades: NRC reauthorises power operation (exemption, licence transfer and amendments to DPR-20) Stage caveat: no new operating licence was issued. The NRC restored the power-operations licensing basis under the existing renewed licence DPR-20, which had been restricted by the 2022 decommissioning certifications. operating-licence-issued is the nearest stage in the vocabulary. It is not evidence that the reactor has restarted. | 2025-07-24 | US Nuclear Regulatory Commission | Renewed Facility Operating License DPR-20 · Docket 50-255 · ADAMS ML25167A245, ML25157A127, ML25157A107, ML25150A281, ML25156A045 | Palisades Energy, LLC; Palisades Nuclear Plant; Exemption (FR Doc 2025-14334) |
| Oklo | First criticality retracted Aurora first criticality Seed placeholder created to exercise the pipeline, never sourced. Its target dates were illustrative, and a reader on /licensing/ could not distinguish it from a sourced milestone. Retracted rather than deleted so the record of having published it survives. | 2027 | US Nuclear Regulatory Commission | no anchor | Hermes – Kairos Application |
| Oklo | First criticality claimed Groves Isotope Test Reactor first criticality (Oklo-reported) Operator-reported. Under DOE authorisation, not NRC licensing; no regulator document or reference number was available. Oklo also calls it the first reactor under the DOE pilot programme to reach criticality on private land; that comparative claim is not recorded as fact. | 2026-08-05 | — | no anchor | Oklo Inc., Form 10-Q for the quarter ended 30 June 2026 |
| Oklo | Application denied achieved NRC denies Aurora combined licence application | 2022-01-06 | US Nuclear Regulatory Commission | Docket 52-049 · ADAMS ML21357A034 (denial letter) | Oklo Power LLC; Oklo Aurora Combined License Application Idaho National Laboratory — denial (87 FR 1441) |
| Kairos Power | Hermes test reactor — latest date for completion of construction under permit CPTR-6 target No regulatory stage recorded | 2029-04-30 | US Nuclear Regulatory Commission | CPTR-6 amendment order 2026-05-13 · Docket 50-7513 · ADAMS ML26083A275 (request), ML26085A103 (safety evaluation) | In the Matter of Kairos Power LLC; Hermes Test Reactor; Extension of Latest Date for Completion of Construction |
| Oklo | Aurora-INL: DOE approves Preliminary Documented Safety Analysis (Oklo-reported) claimed No regulatory stage recorded No stage and no regulator: this is a DOE authorisation step (the second of five, per Oklo), not an NRC licensing stage, and the dataset has no DOE organisation record. No docket or DOE document number is available, so the milestone is unverifiable from outside and rests on the developer's own report. | 2026-06 | United States Department of Energy | no anchor | Oklo Inc., Form 10-Q for the quarter ended 30 June 2026 |
| Oklo | Groves Isotope Test Reactor: DOE startup authorisation (Oklo-reported) claimed No regulatory stage recorded No stage and no regulator: a DOE Reactor Pilot Program authorisation, not an NRC operating licence. No reference number is public in any source opened; unverifiable from outside. | 2026-07-23 | United States Department of Energy | no anchor | Oklo Inc., Form 10-Q for the quarter ended 30 June 2026 |
Target dates
Oklo — Aurora first criticality
- 2024 (said 2020)
- 2026 (said 2023)
- 2027 current
Kairos Power — Hermes test reactor — latest date for completion of construction under permit CPTR-6
- 2026-12-31 (said 2023-12-14)
- 2029-04-30 current