DOE's NEPA determination DOE-ID-26-005, signed on 22 April 2026 by a DOE NEPA compliance officer, decided that Ward 250 fits categorical exclusion B5.26 and needs no further NEPA review (csite-020). Federal law defines a categorical exclusion as a category of actions an agency has determined 'normally does not significantly affect the quality of the human environment' (42 U.S.C. 4336e(1)). B5.26 still requires DOE to determine that a project's attributes 'reduce sufficiently the risk of adverse offsite consequences' (CX p. 6), and the determination summarizes what the 'Documented Safety Analysis demonstrates' (p. 5). Nuclear-safety authorization is a separate track with separate officials. Under DOE's nuclear safety rule, a contractor 'may not begin operation' of a new Hazard Category 1, 2 or 3 facility before DOE issues a safety evaluation report approving its safety basis (10 CFR 830.207(a)); Valar's NSDA names 10 CFR 830 as its governing rule and classes Ward 250 as Hazard Category 2. DOE-STD-1271-2025 makes DOE's Office of Nuclear Energy the Safety Basis Approval Authority, which approves the Safety Evaluation Report, and the Secretary of Energy (or a delegate) the Startup Approval Authority, and says satisfactory completion of a DOE readiness review 'results in DOE issuing Startup Approval'. DOE's Office of Environmental Management wrote on 14 July 2026 that readiness assessments 'are necessary for NE to authorize startup' and that its staff took part in the readiness review for the four pilot reactors, naming Ward 250 (dir-031). So the categorical exclusion is neither DOE's safety approval nor evidence that the safety review was skipped. What is public from each track: the NEPA determination is posted; from the safety track, DOE's statements that Ward 250 was authorized (orig-010) and that readiness reviews took place (dir-031) are public, while no public copy of the safety evaluation report, the approved safety basis or the startup approval was found (safe-007).

• NEPA Determination DOE-ID-26-005: Valar Ward250 Research Reactor (categorical exclusion B5.26) (U.S. Department of Energy, Office of Nuclear Energy, 2026-04-22) primary government “reduce sufficiently the risk of adverse offsite consequences”
• 42 U.S.C. 4336e: Definitions (NEPA sec. 111) (Office of the Law Revision Counsel, U.S. House of Representatives (uscode.house.gov)) primary government “normally does not significantly affect the quality of the human environment”
• 10 CFR Part 830: Nuclear Safety Management (2024 edition), sec. 830.207(a) (U.S. Government Publishing Office (govinfo.gov), Code of Federal Regulations, 2024 annual edition, 2024-01-01) primary government “a contractor may not begin operation of the facility or modification prior to”
• DOE-STD-1271-2025, Authorization Pathway for Nuclear Facilities, sec. 3.0 and 9.1 (DOE standard; copy published by the Nuclear Innovation Alliance) (U.S. Department of Energy (hosted by Nuclear Innovation Alliance), 2025-08) primary government “Satisfactory completion of the DOE Readiness Review results in DOE issuing Startup Approval”
• EM Specialists Help DOE Achieve Criticality Milestones for Advanced Reactors (U.S. Department of Energy, Office of Environmental Management, 2026-07-14) primary government “The assessments are necessary for NE to authorize startup for the reactors.”
• Ward250 Nuclear Safety Design Agreement, No. 100403, Rev 02 (status: Draft; issued for Public Release) (Valar Atomics, 2025-10) primary company “Hazard Category 2 designation based on material at risk”
• eCFR version history, 10 CFR Part 830 (latest amendment date 2020-11-18) (Office of the Federal Register, eCFR (ecfr.gov)) primary government