Thermodynamic Equilibrium Calculations on the Oxidation Behavior of the Mo-Ru-Rh-Pd Alloys
Mo-Ru-Rh-Pd 合金の酸化挙動の熱力学的評価

Yuji OHISHI, Ken KUROSAKI, Tohru SUGAHARA, Aikebaier YUSUFU, Yusuke MASAHIRA, Hiroaki MUTA, Shinsuke YAMANAKA, Satoshi KOMAMINE, Toshiki FUKUI, Eiji OCHI
2012 Transactions of the Atomic Energy Society of Japan  
Thermodynamic equilibrium calculations using the FactSage program package were performed to investigate the oxidation behavior of a Mo Ru Rh Pd alloy, which is well known as the undissolved residue in the reprocessing process. The in‰uences of temperature, oxygen partial pressure, and Pd concentration on the equilibrium composition, melting temperature, and activities were evaluated. On the basis of the computed T P O2 phase diagram of Mo 0.3 Ru 0.5 Rh 0.1 Pd 0.1 , the stable compositions
more » ... Mo 0.3 Ru 0.5 Rh 0.1 Pd 0.1 under the conditions of a high-burnup UO 2 fuel and a glass melter were evaluated. The computed phase diagram showed that under an oxygen pressure of 0.2 Pa, RuO 2 , Rh 2 O 3 , the FCC phase, and MoO 3 (liquid or gas) are stable at T=1,000 1,200°C. The computed phase diagram also showed that precipitates in the glass provide information on the oxygen partial pressure and temperature of the glass in the melter. The computation of the phase diagram was also carried out for Mo 0.3 Ru 0.5 Pd 0.2 . The resultant phase diagram was compared with that of Mo 0.3 Ru 0.5 Rh 0.1 Pd 0.1 to investigate the eŠect of Pd concentration on the oxidation behavior of a Mo Ru Rh Pd alloy. Based on the computed temperature-concentration phase diagram and activities of Mo, Ru, Rh, and Pd in the HCP phase, the eŠect of Pd concentration on the stability of each metallic species was discussed.
doi:10.3327/taesj.j11.010 fatcat:onzln676y5e3rpyw7smafqm5ua