Flooding at Cooper Station encroached on safety-related electrical circuits / Credit: Light HawkThe U.S. Nuclear Regulatory Commission (NRC) is moving forward with a proposed rulemaking to eliminate its requirements for offsite emergency preparedness around a new generation of Small Modular Reactors (SMR) and other contemplated non-light water reactors. The NRC staff acknowledges that the rule change could also apply to aging, large conventional light water reactors in the US, the brunt of which have had their licenses extendedby decades.
The federal nuclear agency publicly posted the Commission's approval and Vote Record (NRC Accession No. ML19353C623) on January 2, 2020 for its “Proposed Rule: Emergency Preparedness for Small Modular Reactors and other New Technologies” (SECY-18-0103). With only one design (NuScale) currently under review by the NRC, many government and public stakeholders see the vote as premature given the agency has yet to certify the safety of a SMR design. The rule, if adopted, would base the size of the radiological emergency planning zone (EPZ) on a mathematical model of the projected dose of radiation to the public from a “credible” nuclear accident that would exceed 1 REM. Even though current SMR design concepts and economical models are based on constructing a single control room to operate multiple, individual “modular” units on the same site , the “credible” accident scenario is limited to a single unit having an accident no matter how many contiguous units are actually operating at the site.
The Commissioners voted 3 to 1 (one vacant Commission seat) to publish the proposed rule in an upcoming Federal Register which will commence a 60-day public comment period. Commissioner Jeff Baran cast the lone vote to oppose the rule as written. Commissioner Baran warns that the proposed rule is “flimsy” when compared to current emergency planning and reverses four decades of agency practices where emergency preparedness and evacuation planning for surrounding communities within a 10-mile radius of all conventional atomic reactor sites is the last line of a “defense-in-depth” philosophy of multiple layers of defense. The rule change explicitly permits the nuclear utilities’ emergency preparedness plan to be limited to the reactor site’s fence line.
Without offsite radiological emergency planning, the role of the Federal Emergency Management Agency (FEMA) to evaluate the adequacy of a site's emergency plans would be diminished if not eliminated. The draft proposed rule would further eliminate the requirement for ”ingestion pathway zones” (IPZ) established to prevent and minimize radiological exposure to surrounding populations out to a 50-mile radius around conventional light water reactors. The NRC would no longer require a specific drill frequency for emergency planning exercises or a coordinated response between the federal, state and local emergency response agencies around new proposed SMR facilities.
Commissioner Baran’s dissenting comments reveal that FEMA, the federal agency responsible for disaster planning, has identified several significant problems with the NRC draft rule including the NRC and industry’s mathematical methodology can be applied to larger US reactors to shrink the EPZ and reduce the cost of the current level of readiness and radiological protection for the surrounding civilian populations. The NRC staff is in fact explicitly asking for public comment on the agency adopting the use the same formulaic approach to reduce emergency planning zones around the nation’s larger, aging light-water reactors.
The FEMA critique points out that the NRC draft rule does not consider a “credible” nuclear accident would affect more than one SMR module despite present design concepts that use a common control room for multiple, contiguous units located on the same site. The NRC staff argues that their new EPZ sizing methodology only applies singularly to each reactor unit in isolation. However, Commissioner Baran and FEMA recognize that the new methodology ignores how severe natural disasters (earthquake, flood and other extreme events) can simultaneously damage multiple reactors at a site as happened at Japan’s Fukushima Daiiichi nuclear power station following the severe earthquake and tsunami. While each individual SMR would be 300 Megawatts electric or less, the combined power and thermal output of two or more SMRs can be cumulatively larger than some existing large light-water reactors.