Estimation of the cesium concentration in spent zeolite vessels

Morita, Keisuke ; Yamagishi, Isao ; Nishihara, Kenji  ; Tsubata, Yasuhiro   

Zeolite is used for adsorption of cesium in the treatment system for contaminated water generated at the Fukushima Daiichi Nuclear Power Plant. Spent zeolite enclosed in stainless steel vessels needs to be stored for a long term; therefore, the hydrogen production by radiolysis of water and corrosion of the vessel under zeolite coexistence needs to be clarified for the safe storage of spent zeolite. The kinetics of cesium adsorption on herschelite, which is used as a zeolite-like adsorbent at the Fukushima site, was investigated to estimate the cesium concentration in spent zeolite vessels. The distribution of cesium in the bed depends on the salt concentration of the feed solution. A simulation code was developed to calculate both the concentration and distribution of Cs and Cs in spent vessels, and the results of calculations were in good agreement with those of experiments.