Development of advanced loop-type fast reactor in Japan, 3; Easy inspection and high reliable reactor structure in JSFR

Sakamoto, Yoshihiko ; Kubo, Shigenobu ; Kotake, Shoji; Kamishima, Yoshio*

JSFR has the advanced loop type layout. In this paper, advantages of the advanced loop type reactor are presented in terms of reliability on the reactor structure. Compact design of the RV enables its manufacture in a factory which has high quality welding and precise machining. The RV has high reliability against thermal stress due to application of ring-shaped forgings around high stress parts. The in-vessel structures are simple, and this makes the approach to inspection targets easy. In JSFR, sodium boundary area is reduced significantly, which makes double-walled piping design easier, and reduces welding lines. So, the reactor structure of JSFR is desirable to inspect the in-vessel structures efficiently, and there is a prospect of reliable plant operation. Advanced technologies are also under development to inspect the structures immersed in sodium. In addition, the loop type reactor is suitable under severe earthquake condition as a result of comparative evaluation.