Research on Operational Intervention Levels for the “Ground” Scenario in High Temperature Gas-Cooled Reactor

Abstract Nuclear emergency is the last barrier of defense in the defense-in-depth system of nuclear safety. Operational Intervention Level (OIL) is an important principle in nuclear accident emergency response. When a nuclear accident occurs, together with other operating standards, OIL guides emergency personnel to take appropriate protective actions rapidly, so as to reduce the harm to the personnel and environment to the lowest. In 2017, International Atomic Energy Agency (IAEA) released a new publication on OIL——ERP-NPP-OILs (2017), which is based on light water reactors (LWRs). Due to the differences between high temperature gas-cooled reactor (HTR) and LWR in core type and accident process, the determination OILs will also be different. This paper conducts the application of method in ERP-NPP-OILs (2017) to HTR especially for OIL1 and OIL2, which is mainly focuses on the “ground” scenario. Taking high temperature gas-cooled reactor – pebble-bed module (HTR-PM) as an example, the calculation process and result of OIL1 are given. It has foundational significance for further completing the OIL system matched with HTR characteristics.