Estimation of the unintended depressurization process of Fukushima Dai-ichi NPP Unit 1 with SAMPSON

抄録

TEPCO announced that the safety relief valves of the Fukushima Daiichi NPP Unit-1 were never manually opened during the accident. However, the measured reactor pressure was about 1MPa at 2:43 of March 12. At that moment the reactor vessel bottom head is believed not to have failed according to the severe accident analyses so far. The authors estimated the possible depressurization mechanism using the severe accident analysis code SAMPSON.