Classification and management of accidents of a test gas-cooled reactor with emphasis on hypothetical accidents

摘要

A 10MW High Temperature Gas-cooled Reactor (HTGR) test reactor (termed HTR-10) is being constructed at the site of the Institute of Nuclear Energy Technology (INET) in the northwest suburb of Beijing, about 40km away from the city. It is a pebble bed type HTGR and is expected to become critical in 1999. The key design features of the HTR-10 are derived from the German HTR-Module design. The safety of the test reactor is fundamentally realized by the inherent properties of the reactor core which ensure the integrity of the coated particles of the nuclear fuel. The integrity of further barriers against radioactivity release helps to reasonably minimize the radiological impact on the environment under normal operation and accident conditions. Accident analysis forms the basis of the reactor safety design. In addition to the four categories of design basis accidents (DBAs) which are analyzed as commonly practiced, one category of hypothetical accidents (HAs) is supplemented to accident classification. The frequencies of some of these HAs are much lower that those of the DBAs. The selection of HAs is based deterministically on engineering experiences with an insight of the occurring probability. Analysis of the HAs shows that without any extra designed systems, the dose limits set for the test reactor will not be exceeded under hypothetical accident conditions. This paper focuses on the classification and management of DBAs and HAs of the HTR-10.