Experimental demonstration on flow diodes applicable to a passive decay heat removal system for sodium-cooled reactors

ナトリウム冷却炉の受動安全崩壊熱除去系のためのフローダイオードの試験による性能確認

近澤 佳隆  ; 相澤 康介 ; 白石 正*; 坂田 英之*

Chikazawa, Yoshitaka; Aizawa, Kosuke; Shiraishi, Tadashi*; Sakata, Hideyuki*

Enhancing passive safety features, the 50MW sodium cooled reactor plant DRACS adopts flow diodes instead of valves which need active signals to activate. In this study, two full scale flow diode models: Type A and B were manufactured and water tests were conducted. The Type A flow diode is a conventional vortex flow diode and the Type B is a modified vortex flow diode which enhances maintenance availability. The Type A flow diode showed good performance while the Type B did not provide enough performance in the test model conditions. Then, flow diodes for the 50MW plant DRACS are designed according to the experimental results. An optimized Type A and modified Type B flow diodes are evaluated to meet requirements of natural convection decay heat removal operation while maintaining the bypass flow in the normal power operation low enough.