Core design of high conversion type FLWR

Nakano, Yoshihiro ; Akie, Hiroshi  ; Okumura, Keisuke ; Okubo, Tsutomu; Uchikawa, Sadao

A core design of a high conversion type innovative water reactor for flexible fuel cycle (HC-FLWR) with thermal output of 3926 MW has been constructed. The design study of HC-FLWR consists of two steps of analyses. The first step was preliminary parametric survey calculations and the second step was more detailed calculations with a nuclear and thermal-hydraulic coupled calculation code MOSRA. Through the 1-D core burnup calculations, the following design values were obtained. The Puf enrichment of MOX fuel is 11%. The heights of upper blanket, MOX and lower blanket regions are 5 cm, 85 cm and 5 cm, respectively. With these values, 3-D core burnup calculations were performed. In this analysis, effects of the fuel loading pattern were also investigated. Finally, a neutronics design of HC-FLWR core with a negative void reactivity coefficient, a conversion ratio of 0.84 and a discharged burnup of 56 GWd/t was obtained.