Thermodynamic assessment of U-Eu-O system

U-Eu-O系の熱力学データベースの構築

勝山 幸三 ; 石見 明洋 ; 三輪 周平  ; 逢坂 正彦  ; 山中 伸介*; 黒崎 健*; 牟田 浩明*; 大石 佑治*; 米田 敦洋*

Katsuyama, Kozo; Ishimi, Akihiro; Miwa, Shuhei; Osaka, Masahiko; Yamanaka, Shinsuke*; Kurosaki, Ken*; Muta, Hiroaki*; Oishi, Yuji*; Yoneda, Atsuhiro*

In the Fukushima Daiichi nuclear disaster, a significant amount of fuel debris was formed in the reactor. Even in the severe accident, special nuclear material (SNM) accountancy of the molten debris is required by the regulatory bodies to ensure no diversion of SNMs. As one of the accountancy technologies, passive spectrometry has been studied. In this method, high-energy gamma-emitting fission products (FPs) are quantified by the passive spectrometry. When the FPs co-exist with the SNM in the debris, the amount of the SNM can be estimated from the FP-SNM correlation obtained by inventory calculation. Eu is a candidate FP since it is one of the high-energy gamma-emitting FPs and known to co-exist with uranium in the normal spent fuels. A thermodynamic database is important to apply this method to the debris. In this study we aim to develop the database for U-Eu-O ternary system by CALPHAD technique.