Mitigation effects using inventory of safety injection tanks for high pressure severe accident sequence

If high pressure safety injection pumps are not working for a total loss of feed water sequence, then this results in a severe accident inevitably. Nevertheless, a rapid depressurization using the POSRV could still mitigate the severe accident by providing a cooling water into a damaged core from safety injection tanks(SIT) which are passive systems. The purpose of this paper is to estimate how long the reactor vessel failure can be delayed by using the passive safety injection tanks for typical high pressure sequences at the KNGR. Based on MAAP calculation, the results show that the reactor vessel failure can be delayed about 7 hours if the inventory of four SITs is effectively used to remove the decay heat through the primary feed and bleed operation