Design study around beam window of ADS

Oigawa, Hiroyuki ; Tsujimoto, Kazufumi ; Kikuchi, Kenji; Kurata, Yuji; Sasa, Toshinobu   ; Umeno, Makoto*; Nishihara, Kenji  ; Saito, Shigeru   ; Mizumoto, Motoharu; Takano, Hideki*; Nakai, Kimikazu*; Iwata, Azuma*

The Japan Atomic Energy Research Institute (JAERI) is conducting the research and development (R&D) on the Accelerator-Driven Subcritical System (ADS) for the effective transmutation of minor actinides (MAs). The ADS proposed by JAERI is the 800 MWth, Pb-Bi cooled, tank-type subcritical reactor loaded with (MA+Pu) nitride fuel. The Pb-Bi is also used as the spallation target. In this study, the feasibility of the ADS was discussed with putting the focus on the design around the beam window. The partition wall was placed between the target region and the ductless-type fuel assemblies to keep the good cooling performance for the hot-spot fuel pin. The flow control nozzle was installed to cool the beam window effectively. The thermal-hydraulic analysis showed that the maximum temperature at the outer surface of the beam window could be repressed below 500 C even in the case of the maximum beam power of 30 MW. The stress caused by the external pressure and the temperature distribution of the beam window was also below the allowable limit.