Fuel assembly design for plutonium conservation in a light water reactor with hard neutron spectrum

軽水冷却高速炉におけるプルトニウム保存型燃料集合体の設計概念

内川 貞夫; 大久保 努; 中野 佳洋 

Uchikawa, Sadao; Okubo, Tsutomu; Nakano, Yoshihiro

プルサーマル燃料技術に立脚し効率的なプルトニウム利用を実現する軽水冷却高速炉用燃料集合体として、MOX燃料とUO燃料棒を燃料集合体内で非均質に配置した新たな設計概念を構築し、使用するMOX燃料ペレットの最大Pu富化度をプルサーマル用燃料加工施設での取扱可能範囲としながら、核分裂性Pu残存比1.0以上を実現できる見通しを得た。

The FLWR is a BWR-type reactor with hard neutron spectrum based on the well-experienced LWR technologies. The present paper has proposed a new concept of the fuel assembly design for the first stage of FLWR to conserve plutonium effectively with a fissile-plutonium conversion ratio of around 1.0, keeping negative void reactivity characteristics. The enriched UO fuel rods are arranged in the peripheral region of the assembly, surrounding the MOX fuel rods in the central region. Performance evaluation shows that the FLWR/MIX concept is effective for controlling the void reactivity characteristics in the tight-lattice fuel rod configuration and promising under the framework of the UO and MOX fuel technologies and related infrastructures which have been established for the current LWR-MOX utilization.