Thermal feasibility analyses for the 1356 MWe high conversion-type innovative water reactor for flexible fuel cycle
Liu, W.; Onuki, Akira; Yoshida, Hiroyuki ; Kureta, Masatoshi ; Takase, Kazuyuki; Akimoto, Hajime
With using the research achievements on thermal-hydraulic characteristics so far derived for the target tight lattice core, this paper studies the thermal feasibility of the designed 1356 MWe FLWR core using a modified transient analysis code TRAC-BF1. The newest critical power correlation developed at JAEA for tight lattice rod bundles is implemented to judge the occurrence of boiling transition from nucleate boiling to film boiling. The pressure drop in two-phase flow region is evaluated by Martinelli-Nelson two-phase multiplier. In the analyses, the 900 fuel assemblies in the designed core are modeled into 12 fuel channels according to the relative mass and power distributions. Analyses to the postulated abnormal transient events that may be possibly met in the operation of the FLWR are performed with MCPRs being evaluated. The necessary coolant flow rate then is calculated based on the evaluated MCPRs. As the results, for a natural circulation type FLWR, the operation limited MCPR is 1.19. For a forced circulation type FLWR, the one is 1.32.