Nuclear Safety, Licensing, and Regulations
Framework
10 CFR 50 and its General Design Criteria anchor design: defense in depth, redundancy, independence, and the single-failure criterion. Design-basis accidents are analyzed with conservative assumptions, and safety analyses are documented in the FSAR under 10 CFR 50.34. Siting criteria live in 10 CFR 100. Changes to the facility or procedures go through a 10 CFR 50.59 screening and evaluation before implementation.
LOCA acceptance criteria (10 CFR 50.46)
Peak cladding temperature ≤ 2200 °F (1204 °C); local cladding oxidation ≤ 17% of total zirconium reacted; hydrogen generation ≤ 1% of that from a full Zr–water reaction; coolable geometry maintained; long-term cooling assured.
Operations-related rules
10 CFR 20 (radiation protection), 10 CFR 55 (operator licensing), 10 CFR 26 (fitness for duty), 10 CFR 50.47 and Appendix E (emergency planning), 10 CFR 50.65 (maintenance rule), 10 CFR 73 (security). The NRC's Reactor Oversight Process uses cornerstones and performance indicators with an action matrix from Licensee Response through Unacceptable Performance.
Traps
- Mixing 10 CFR 100 siting dose criteria with 10 CFR 20 occupational limits.
- Quoting 50.46 criteria incorrectly, especially the 17% oxidation and 1% hydrogen values.
- Assuming Technical Specifications are part of 10 CFR 50 Appendix A; they are plant-specific, derived from NUREG-1430/1431-style standard specs.
Rule of thumb
Any proposed change that could affect a design function described in the FSAR, or that requires a Technical Specification change, must be evaluated under 50.59 before implementation - never after.