An investigation for long-term storage of a spent zeolite adsorption vessel. Estimation of washing out salt component in a spent zeolite adsorption vessel. Part 1

Spent zeolite adsorption vessels for cesium removal (Cesium adsorption vessels) in the Fukushima No.1 nuclear power plant are kept for long-term with washing out with fresh water. Soundness of adsorption vessels is concerned by residual concentration of salt component, effect of washing out chloride ion (Cl-) is inspected with miniature experiments using zeolite and seawater. It is considered that washing out condition is depending on that candidate, thus washing out experiment is necessary to carry out using full-scale and unspent adsorption vessel (KURION). Cesium adsorption vessel is filled with 1,650 ppm of sodium chloride (1,000 ppm of chloride ion) and washed out with filtrate water for estimating washing effect in this experiment. Pure water is streamed with volume flow rate 4.5 m3/h, chloride concentration in vessel is measured with sample of drainage. 1,000 ppm of chloride concentration is decreased till 0.5 ppm and below by washing out with about double pure water volume of adsorbing material filling volume in vessel, washing out is more effective in Cesium adsorption vessel. (author)