Investigation on enhancement of reliability for components of reactor system in sodium-cooled fast reactor toward commercialization

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

This paper describes the enhancement of reliability for components of the reactor system in JSFR design. As for manufacturability, compact design of the RV enables its manufacture in a factory. This results in high quality welding and in precise machining of the RV. The adoption of ring-shaped forgings contributes for securing the reliability against thermal stress as well as securing the dimension precision. Regarding maintenability, the in-vessel structures have simple configurations, so it is comparatively easy for inspection equipments to reach inspection targets. In the JSFR design, sodium boundary area is reduced significantly, which makes double-walled design of the piping easier, and reduces welding lines. So, the reactor system of JSFR is desirable to inspect the in-vessel structures efficiently, and there is a prospect of reliable plant operation. Advanced inspection technologies are also under development for the inspection of the in-vessel structures under sodium.