Safety Evaluations of FBR Power Plants and Fuel Cycle Facilities; Results of the Studies in 2004

Kubo, Shigenobu; Kurisaka, Kenichi; Yamano, Hidemasa; Niwa, Hajime

JNC TN9400 2005-025, 156 Pages, 2005/04

JNC-TN9400-2005-025.pdf:3.71MB

This study is dedicated to establish rational safety design concepts for the power plants and their related fuel cycle facilities in the feasibility study on commercialized fast reactor cycle systems. Major results of this study are as follows. *The principles of safety design and evaluation for the sodium-cooled reacter were formulated as well as the way to achives the equivalent safety level to LWRs,design requirements to eliminate necessity of the evacuation, and the contaiment performance requrement. As a result, the item for further investigation was clarified in the containment design. As for small scale sodium-cooled reacter with metallic fuel,state-of -the -arts of knowledge for the evaluation of GDA, the way for elimiration of re-critically and related design requirements for the reacter core were identifiled. *A preliminary evaluation shoed that the feasibility of molten fuel discharge capability of modified inner duct conceot forsodium-cooled MOX fuel reacters.The three dimentional effect in the course of the transition phase of CDA was investigated and foud that the cooling effect of the control rod guide tube is pronounced comparing with two dimensional case. * A preliminary evaluation showed that the occurrence probability of PLOHS can be reduced by more than one order with help of stome accident management measures such as steam spply to SGs, improvement of diversity for the air cooler dumper. * Concering the SG tube repture for the LBE-cooled reacter, it was found out that certain amoumt of steam can enter into the core in case of one tube rupture at the bottom of SG and that steam jet breaker should be installed in order to avoid massive ateam ingress. * A risk study on some typicals events in the facilities of the suoer-critical direct extraction reprocessing and the extraction chromatography method for MA recovery revealed that their risk levels are sufficiently low.