Technological investigation of the simplified MA-bearing fuel fabrication process for fast reactors and accelerator driven systems

簡素化燃料製造法による高速炉及び加速器向けMA含有燃料製造の技術調査

山田 美一 ; 川口 浩一  ; 瀬川 智臣 ; 松村 達郎  ; 加藤 正人   

Yamada, Yoshikazu; Kawaguchi, Koichi; Segawa, Tomoomi; Matsumura, Tatsuro; Kato, Masato

日本原子力研究開発機構では、廃棄物処分の負担軽減を目指して、高速炉及び加速器を利用したMA分離変換技術の研究開発を進めている。一方、燃料製造コスト低減を目指して、燃料製造工程を簡素化した燃料製造法についても研究開発を進めている。今回、高速炉及び加速器へMA含有燃料を供給するための技術検討として、模擬粉末を用いて簡素化燃料製造法によるMA含有燃料製造試験を実施した。原料粉末は転動造粒することによって流動性が良くなるとともに、ダイ潤滑成型により得られた燃料ペレット外観もクラック等は観察されずに良好であった。また、粒子は均一に分散していることも確認された。結果として、簡素化燃料製造法は高速炉同様、加速器向けの燃料製造法としても有効であることがわかった。

Researchers at Japan Atomic Energy Agency (JAEA) have proposed the transmutation of minor actinides (MAs) by both fast reactors (FRs) and accelerator driven systems (ADSs) as a way to contribute significantly to the reduction of the volume and the potential radiotoxicity of radioactive wastes. Pu-U mixed oxide with small amount of MA is adopted as fuel of FRs, while U-free nitride and mixed oxide of MA, Pu and inert element are candidates for fuel of ADSs. JAEA researchers have also studied the simplified MOX fuel fabrication process to decrease the fabrication cost. This report describes a technological investigation of the simplified MA-bearing fuel fabrication process that prepares fuel suitable for both FRs and ADSs. Furthermore, this report includes an analysis of the feasibility of fabricating MA macro-dispersion pellets and MA micro-dispersion pellets for ADSs by using the simplified MOX fabrication process. The flowabilities of both de-nitrated raw powders were improved with the tumbling granulator, and the Carr flowability index was more than 70 for both. The green pellets had no defects in their appearance such as cracks. The CeO particles were dispersed homogeneously in both macro-dispersion and micro-dispersion pellets. As a result, it was judged that the simplified MOX fuel fabrication process is applicable to fabrication of MOX pellets for ADSs as well as FRs.