Rightsizing the EPZ
The Emergency Planning Zone (EPZ) is the area surrounding the nuclear power plant within which special considerations and management practices are pre-planned and exercised in case of emergency. In practice there are two EPZs surrounding the plant site. The first, called a Plume Exposure Pathway, is traditionally at a 10 miles radius for conventional nuclear plants, and is designed to avoid or reduce the dose from potential exposure of radioactive materials from the plant. The second, called the Ingestion Exposure Pathway, is about 50 miles in radius for conventional nuclear plants, to avoid or reduce the dose from potential ingestion of food contaminated by radioactive materials. For both zones specific emergency procedures are in effect.
The exact size and shape of each EPZ is determined by careful consideration of the following factors: 1) the operating characteristics of the plant, 2) the geographical features where the plant is located, and 3) the population areas surrounding the plant. Under an emergency, managing the EPZ becomes very important for the plant itself and the areas beyond the EPZ.
As the NuScale SMR is so much smaller and safer than large nuclear reactors, rightsizing the EPZ is important. The EPZ is expected to be smaller since our safe design means there is less likelihood that something unexpected, such as severe accidents, would occur. Also a smaller reactor core means less radioactive material that could be released in an accident.
NuScale Power worked with the Nuclear Energy Institute (NEI) to develop methodologies to support smaller EPZs for SMRs for discussion with the NRC. In December 2015, NuScale submitted a topical report to the NRC detailing its proposed methodology for NuScale Plant licensees to determine the appropriate EPZ.
Why is the NuScale SMR safer? Our safety features make the difference: