The measurement of inventory of Cs, Sr and I in the gap of G23-J11 spent fuel rod

The inventories of soluble nuclides in the gap, known to be released rapidly from the spent fuel into water, were measured. When the specimen of G23-J11 spent PWR fuel rod was leached in distilled water, the release rates of nuclides were sloped as a function of leach time. The slop rapidly decreases at the initial stage and then sluggishly decreased. And so, it is assumed that the gap inventory would be equal to the cumulative release fraction prior to reaching at the sluggish slope of the release rate. Then, the gap inventories of cesium, strontium and iodine for G23- J11 were 0.2%, 0.044% and less than 0.2%, respectively