Phase stability of Cs-Si-O and Cs-Si-Fe-O compounds on stainless steel
摘要
During a severe accident (SA) such as the Fukushima Daiichi Nuclear Power Plant accident, fission products (FPs) can be retained on the surface of structural materials in reactors. Cesium (Cs) is an important FP, and various Cs compounds such as Cs silicates are formed on the surface of stainless steel (SS) in a reactor during a SA. We calculated total energies of Cs-Si-O compounds for evaluation of phase stability within an adiabatic approximation. The calculations indicate that Cs6Si10O23 is the most stable of the Cs-Si-O compounds. We calculated, furthermore, total energies of Cs-Si-Fe-O compounds. These calculations indicate that Cs-Si-Fe-O compounds are more stable than C-Si-O compounds and that CsSi2FeO6 is the most stable of these C-Si-O and Cs-Si-Fe-O compounds within an adiabatic approximation. The results of our present calculations and our previous experiments lead to the conclusion that Cs-Si-Fe-O compounds can be stably formed on SS surface by Cs chemisorption.