Abstract
The objective of this study is to investigate the integrity criteria for coolant boundary structures of sodium cooled fast breeder reactors (FBRs) during the typical severe accident such as a protected loss of heat sink (PLOHS) from the viewpoint of the probabilistic safety assessment (PSA). It was found that the integrity criteria for the FBR coolant boundary "700℃ with 1000 hours and 750℃ with 100 hours" would be suitable based on the structural analysis with elasticity and plasticity under the PLOHS conditions for the temperature and pressure given by the plant dynamics analyses.
