Evaluation of double leakage at primary heat transport systems of Monju with passive safety features

Yoshimura, Kazuo; Ikeda, Makinori; Enuma, Yasuhiro  ; Aizawa, Kosuke 

JAEA has conducted a safety evaluation of impacts of double leakage at the PHTSs considering the passive safety features of Monju as the best-estimate evaluation for a DEC. The result shows that the total amount of leaked sodium can be reduced by the depressurization of the cover gas resulting from decrease in coolant inventory, i.e. negative pressure effects. The reactor coolant level required for decay heat removal, therefore, can be maintained even under double leakage at the PHTSs.