NRC to Develop Rules for Emergencies at Small Modular ReactorsEngineering360 News Desk | August 10, 2015
The U.S. Nuclear Regulatory Commission (NRC) will develop emergency preparedness regulations for small modular reactors (SMRs) and other new technologies such as non-light-water reactors (LWRs) and medical isotope production facilities.
NRC commissioners have approved a staff recommendation to initiate the work on August 4, directing that a plan and schedule for the rulemaking be drawn up within the next nine months. The staff recommendation, submitted in May, anticipated to establish a generic technical framework that could be used to draw up emergency preparedness plans for SMRs and other new technologies that would better reflect the likely impacts of an accident at the plant in question, reports World Nuclear News.
Emergency preparedness is based upon the projected off-site radiation dose in the event of a severe nuclear accident. The U.S.’s current framework is based around the LWRs that make up the country's operating nuclear fleet, and establishes two emergency planning zones around a plant: a 10-mile zone, within which action might need be taken to provide protection from airborne radiation; and a 50-mile zone in which food and water would need to be monitored for contamination.
SMRs have much smaller reactor cores than the large reactors currently in operation, plus design features to reduce the off-site impact of any accident. Such features mean that the impact of any radiation released in a severe accident at an SMR would be likely to occur over a smaller area, and possibly over a longer time, than for an LWR plant. The potential need for a smaller emergency planning zone could be an important factor for reducing regulatory uncertainty for both SMR design certification and combined construction and operation license applications, according to the NRC.
In giving their approval, the NRC commissioners say the rulemaking would provide an opportunity to "further explore the pros and cons of a performance-based EP framework.” For any SMR reviews conducted prior to the establishment of a rule, NRC staff should be prepared to adapt an approach to emergency planning zones for SMRs under existing exemption processes, they say.
The NRC is preparing for the first license applications for SMR designs, which differ from the current generation of large LWR facilities, by working to resolve key safety and licensing issues and develop a suitable regulatory infrastructure.
NRC staff are currently engaged in pre-application activities for four SMR designs—NuScale SMR, B&W mPower, Holtec SMR-160 and Westinghouse SMR. NuScale Power and Utah Associated Municipal Power Systems recently confirmed that they plan to submit a design certification application to regulators by the end of 2016 and an application for a combined construction and operation license in late 2017 or early 2018. The Tennessee Valley Authority is also expected to submit an early site permit for two or more small reactors at its Clinch River site during 2016.