Chemisorption behavior of CsOH vapor on UO under high temperatures and various water vapor concentrations

Mohamad, A. B. ; 中島 邦久 ; 井元 純平*; 高野 公秀 

Mohamad, A. B.; Nakajima, Kunihisa; Imoto, Jumpei*; Takano, Masahide

It is estimated that considerable amounts of Cs remain in the reactors at the Fukushima Daiichi nuclear power plant and may react with the reactor materials such as UO fuel as reported by our previous paper. In order to understand the chemisorption behavior of CsOH vapor on UO fuel, chemisorption tests between CsOH vapor on UO under different water vapor concentrations and temperatures were performed. As predicted by the thermodynamic analysis, the experimental result indicated that, under the poor water vapor condition, chemisorption to form CsUO occurred even at 1273 K. On the other hand, as predicted by the thermodynamic analysis, the experimental result indicated that, under the rich water vapor condition, chemisorption to form CsUO occurred at 1273 K and 1473 K. Therefore, this study demonstrates the crucial role of thermodynamics in predicting the conditions under which chemisorption occurs. In addition, it was suggested that the chemisorption rate of CsOH vapor on UO pellet was considerably higher than that onto type 304 stainless steel.