Current emergency planning requirements for the US were established in NUREG — 0396 (EPA-520/1-78-016), and are incorporated in 10 CFR Part 50, Appendix E, ‘Emergency Planning and Preparedness for Production and Utilization Facilities’. These requirements establish a plume exposure pathway emergency planning zone (EPZ) of 10 miles (16 km), and an ingestion exposure pathway of about 50 miles (80 km) for large LWRs. Appendix E recognizes that certain reactor designs may warrant an exemption from these requirements on a-case-by-case basis. (See footnote 1 of Appendix E.) SMR designs offer a basis to revise these EPZs based on a significantly reduced potential for offsite releases from postulated accidents. The design-specific PRAs will provide a good basis to revise emergency planning requirements based on substantially reduced risk to public health and safety. With expected enhancements to SMR designs for safety, the NRC staff believes that SMRs may develop reduced EPZ sizes commensurate with their accident source terms, fission product releases, and accident dose characteristics.

The NRC staff analyzed the potential for reduced EPZ sizes in SECY-11-0152 (28 October 2011). It considered it acceptable for SMR vendors to establish an appropriately reduced EPZ size based on the factors noted above regarding source terms, releases and dose characteristics. The staff noted a need to further review the ‘modularity’ and ‘co-location’ of SMR reactors. This review will focus on the fact that several SMR designs will be based on multiple reactors being located together in a common facility. Vendors are designing these SMRs so that the reactor modules will be independent — i. e. an accident in one module will not initiate or exacerbate an event at another module. This independence permits smaller source terms and potential releases to the public. Based on these design considerations, the NRC will consider a scalable EPZ size based on offsite dose to the public, and emergency planning measures within the EPZ based on transient time and existing capabilities of federal, state and local response organizations. This approach would not result in a reduction to public health and safety.

Emergency planning size and response measures are important for international consideration and licensing. The NRC’s evaluation of this issue based on offsite dose considerations of new designs and appropriate response measures for the population at risk is instructive for international licensing. International licensing considerations for EPZ size and response measures are unique for extremely remote sites. The NRC has not considered extremely remote sites since there is no pending SMR application with a remote site under consideration.

Important to the US evaluation of reduced EPZ size and measures to be taken within the EPZ, is that response capabilities of offsite personnel and emergency organizations were bolstered significantly in response to the terrorists’ events of 11 September 2001. Federal and state response capabilities are bolstered by better equipment, communications, coordination, and training — all of which are important capabilities to respond to a nuclear event. Additionally, in the post-Fukushima environment, nuclear power operators are considering better coordination and integration of capabilities to respond to an operating plant event. International emergency planning licensing should also consider these factors on a country or regional basis.