Fundamental research on fission product chemistry, 2; The Atmospheric effect on the Cs deposition behaviors onto stainless steels

Nakajima, Kunihisa  ; Suzuki, Eriko   ; Osaka, Masahiko  

There are a large amount of stainless steels used for the reactor pressure vessel internals. So the cesium (Cs) deposition behavior might influence the Cs release and transport behaviors during severe light water reactor accidents. Thus, atmospheric effect on the Cs deposition behaviors onto stainless steels exposed to cesium hydroxide vapor was investigated. As the results, the Cs deposited amounts under oxidizing conditions such as mixed gas of argon, steam, and hydrogen (Ar-H-HO) were found to increase compared with those under the reducing condition of Ar-5%H. Furthermore, the cross-sectional observation of the Cs deposited layers by using a scanning electron microscope with an energy dispersive spectrometer suggested that revaporization of the deposited Cs occurred especially under the Ar-5%H reducing condition.