Water-leaching behavior for cesium chemisorbed on stainless steel at room temperature

Nakajima, Kunihisa  ; Imoto, Jumpei*; Nishioka, Shunichiro*; Osaka, Masahiko  ; Miwa, Shuhei  

Water-leaching tests at 303 K were performed on cesium (Cs) chemisorbed on stainless steels to investigate its long-term dissolution behavior. The findings showed that Cs continued to dissolve into water even after 1200 hours and that Cs was found to coexist with silicon as ring-shaped particles. This indicates that even water-insoluble Cs, which is defined in the Cs-chemisorption models incorporated into existing SA analysis codes, can dissolve in water over extended periods, with the dissolution attributed to the ring-shaped Cs silicate particles. Additionally, these water-leaching behaviors were accurately described by the Noyes-Whitney equation, suggesting the potential development of a water-dissolution model for the water-insoluble Cs in the chemisorption models. These insights imply that long-term redistributions of chemisorbed Cs could occur within the reactor pressure vessels in Fukushima Daiichi Nuclear Power Station, necessitating a water-dissolution model to predict redistributions through the aqueous phase.