Design range of Fast Reactor with Inherent Safety for Effective Transmutation of Minor Actinide: 1. Screening with constraint of negative void reactivity

抄録

To improve the social acceptance of a nuclear power plant, the effective Minor Actinide (MA) transmutation by fast reactors with inherent safety has been studied in Japan. However, the design range of the fast reactor with inherent safety has not been clarified well. The negative void reactivity coefficient is the one of recommended requirements of inherent safety. Therefore, in this study, the feasible range of design parameters is clarified for the fast reactor with MA under the constraint of negative void reactivity. Furthermore, the maximum amount of MA transmutation and the design parameters are clarified.

First, various core designs are considered by changing four design parameters: core volume, MA mass fraction in fuel, the volume fraction of fuel containing MA, and the arrangement of these fuels. Second, the void reactivity is used for screening these core designs. The fast reactor has two fuel regions: the first one is the fuel region with MA, and the second one is without MA. The MA composition is referred from the discharge fuel of the light water reactor. The ratio of the radius to the height of the reference core is fixed at 3/4. As a result, the feasible range of parameters for the fast reactor with inherent safety is clarified in terms of “the core volume”, “the mass fraction of MA in the fuel”, “volume fraction of the MA containing fuel region”, and “the arrangement of these fuels”.