Development of Severe Accident Evaluation Technology (Level 2 PSA) for Sodium-cooled Fast Reactors (3) Identification of Dominant Factors in Transition Phase of Unprotected Events

摘要

The event progression of the transition phase in the unprotected loss of flow accident of the JSFR design concept was analyzed using the SIMMER-III code reflecting the knowledge obtained from the EAGLE experimental program. It was clarified through the parametric calculations that the fuel discharge behavior through the paths such as the inner duct of modified-FAIDUS and control-rod guide tube is playing a very important role. Effective fuel discharge through these paths prevents possibility of severe recriticality events. Important factors dominating the transition phase were identified through these parametric calculations.