Estimation of the inventory of the radioactive wastes in Fukushima Daiichi NPS with a radionuclide transport model in the contaminated water

Shibata, Atsuhiro  ; Koma, Yoshikazu  ; Oi, Takao 

For planning and investigating on treatment and disposal of the wastes on Fukushima Daiichi NPS, it is necessary to quantify the radioactivity inventory of them. The secondary wastes from the water treatment system are one of the major wastes and the analysis of the water of the treatment system holds the promise of giving the useful information on the inventory of damaged fuel. Therefore, the inventories of the secondary wastes and damaged fuel were estimated with a radionuclide transport model in the contaminated water. The model was developed based on unknown factors that are initial concentration in the hypothetical volume assuming the instantaneous homogeneous mixing and continuous release rate from damaged fuels. In the numerical analysis using this model, the key parameters, initial concentration C, continuous release rate F and inventory of source of continuous release I were given by fitting the model with analysis data of the contaminated water. By using these parameter values, the nuclides inventories in the damaged fuel and secondary waste were calculated.