マイクロ波加熱直接脱硝法による混合転換プロセスの実証20年の歩み; プルトニウム転換技術開発施設の運転経験と技術開発

History of 20 Years Demonstration of Pu-U Co-Conversion Process using a Microwave Heating Direct Denitration Method; Operational Experiences and Developments at the Plutonium Conversion Development Facility

細馬 隆   ; 市毛 浩次; 高橋 芳晴

Hosoma, Takashi; Ichige, Koji; Yoshiharu, Takahashi,

日米原子力交渉の結果、プルトニウム・ウラン混合転換技術開発が開始され、国際合意が得られた経緯、マイクロ波加熱直接脱硝法の実証運転の経過、物質収支、粉末特性、工程特性、実証運転と並行して進められた技術開発と基礎研究、六ヶ所再処理工場への技術移転等についてまとめた。

The application of the fluoride volatility process in the reprocessing of fuel from the fast breeder reactor is regarded as one of the economical methods. Plutonium hexafluoride (PuF6), however, reacting with fluorine (F2) and plutonium dioxide (PuO2) as the raw material, is in an unstable condition and tends to remain as a solid compound in the process after decomposing into plutonium tetrafluoride (PuF4). Suitable conditions should be established for the practical use of this process. One of them is to enhance the stability of PuF6. The behaviour of plutonium fluorination and relevant chemical reactions were investigated by referring to sundry literature and by thermodynamic calculation. It was then compared with recent data from laboratory scale experiments for this paper. Results from the theoretical analysis agreed with experimental observation that PuF6 could be formed stably under a high temperature condition (approx.1000 K) with over supply of figher concentration of F2.