Conceptual design study for the demonstration reactor of JSFR, 3; Safety design and evaluation

Tani, Akihiro*; Shimakawa, Yoshio*; Kubo, Shigenobu* ; Fujimura, Ken; Yamano, Hidemasa   

This paper describes the result of conceptual safety design and evaluation for the demonstration plant of Japan Sodium-cooled Fast Reactor (JSFR) to obtain necessary information to decide the plant specification for further study. Major specifications except for output power and safety design concept are similar to those of the commercial JSFR. A set of safety evaluation for typical design basis events (DBEs) is mainly focused here, which was conducted for the 750 MWe design. Safety analyses for DBEs evaluation were performed on the basis of conservative assumptions using a one-dimensional flow network code with point kinetics. For representative DBEs, transient over power type events and loss of flow type events were analyzed. The long-term loss-of-offsite power event was also calculated to evaluate the natural circulation decay heat removal system. All analytical results met tentative safety criteria, thus it was confirmed the safety design concept of JSFR is feasible against DBEs.