Technical Basis and Analytical Methods Development Supporting the U.S. EPR Severe Accident Mitigation Features

摘要

In accordance with the U.S. Nuclear Regulatory Commission's (U.S. NRC) policy statements on severe accidents and advanced reactors, new reactor designs must demonstrate improved severe accident characteristics compared to the operating reactor fleet. This requirement is generally considered in two distinct ways: 1. New reactors will have a lower probability of occurrence of severe accidents, as measured by their core damage frequency (CDF) in a full-scope Level 1 probabilistic risk assessment (PRA); and 2. New reactors will have improved capabilities of mitigating the consequences of severe accidents, should they occur, as measured by the large early release frequency (LERF) or other similar metrics (e.g., conditional containment failure probability), as demonstrated in a Level 2 PRA.