Investigation of the core neutronics analysis conditions for evaluation of burn-up nuclear characteristics of next-generation fast reactors

Takino, Kazuo ; Sugino, Kazuteru; Yokoyama, Kenji   ; Jin, Tomoyuki*; Oki, Shigeo 

Since next-generation fast reactors aim to achieve a higher core discharge burn-up than that of the conventional ones, nuclear design methods need to improve. In this study, we investigated the effect that the analytical conditions exhibit on the accuracy of estimations of the burn-up nuclear characteristics of next-generation fast reactors. Suitable analytical schemes and conditions that maximize the estimation accuracy, while maintaining a low computational cost, were investigated in this study. We performed core burn-up survey calculations under several analysis conditions. Furthermore, we calculated the criticality, burn-up reactivity, control rod worth, breeding ratio, assembly-wise power distribution, maximum linear heat rate, sodium void reactivity, and Doppler coefficient for the equilibrium operation cycles. The accuracy of the low-cost calculations was evaluated by measuring the agreements with the referential detailed conditions.