The National Fire Protection Association (NFPA) approved NFPA Standard 805, “Performance-Based Standard for Fire Protection for Light-Water Reactor Electric Generating Plants, 2001 Edition” (NFPA 805) on January 13, 2001. This alternate fire protection rule [10 CFR 50.48(c)] describes a new, risk-informed, performance-based standard for existing light-water nuclear power plants and introduces a more objective, data-driven method of making U.S. nuclear power plants safer. The NRC has modified its fire protection regulations to allow licensees to transition voluntarily to NFPA 805 in lieu of their existing fire protection licensing basis.
Why NFPA 805?
The existing deterministic fire protection requirements, otherwise known as Appendix R, focus on establishing a fire protection engineering margin based on the post-fire survival of limited safety systems capable of hot and cold shutdown. The regulation was established before the industry had the benefit of probabilistic risk assessments (PRAs), and before advances in performance-based methods.
NFPA 805 provides a methodology for applying risk-informed performance-based methods to establish fire protection features and design elements for all modes of reactor operation. Applying this data-driven method makes nuclear power plants safer. Because it is focused on PRAs and performance-based methods, the regulation also provides a sequence to follow for establishing “fire protection procedures, systems, and features for nuclear power plants that are decommissioned and permanently shut down.”
Many plants prefer to follow the NFPA 805 guidelines because they were written to take advantage of advances in the science of fire protection. Plants have the flexibility to operate based on successful performance, whereas the Appendix R regulation is prescriptive, there is no fire modeling, and nuclear power plants must follow each rule regardless of its applicability.
Currently, more than 40 plants are in the process of transitioning or plan to transition to the NFPA 805 standard.
NFPA 805 and ARS
The staff at ARS includes recognized field experts who have worked as licensing operators, shift engineers, station operations managers, and utility fire protection/safe shutdown owners, as well as former utility licensing managers. ARS has a thorough knowledge of all safety-related features of multiple nuclear power plants operating within a variety of designs and we know which features are most essential to fire protection and safe shutdown. Additionally, the ARS staff is skilled in use and implementation of PRAs, which can provide a quantitative assessment of the risk of accidents in nuclear power plants. With a wide variety of educational and industry backgrounds, ARS’s fire protection engineers have experience with a range of fire models, which can help predict the risk of a fire in a nuclear power plant. When a risk is predicted, ARS engineers work with plant technicians to develop modifications or programs to minimize or eliminate that risk.