The inventory estimation of long-lived fission products (LLFP) is essential for the long-term safety assessment of a geological disposal of high-level radioactive waste (HLW). 79Se and 135Cs are a main contributor to the total dose from the geological repository of HLW, owing to their solubility in the strata. In this study, the post-irradiation experimental data of LLFPs, such as 79Se, 99Tc, 126Sn and 135Cs, were compared with ORIGEN2 calculation using the data library of JENDL-3.3. A fragment of the UO2 fuel pellet irradiated in a commercial Japanese PWR was dissolved with nitric acid in a hot cell. The resultant solution was filtered to remove insoluble residue. After Se, Tc, Sn, and Cs were chemically separated, the concentrations of 79Se, 99Tc, 126Sn and 135Cs were determined with an inductively coupled plasma quadrupole mass spectrometer (ICP-QMS). The concentration of 79Se, 99Tc, 126Sn and 135Cs in the sample solution were 0.78 ± 0.22, 101 ± 24, 3.2 ± 0.6, and 68 ± 6.0 ng/g of the sample solution (ng/g-sol.), respectively. The results for 79Se and 135Cs obtained in this study showed good agreement with those obtained through ORIGEN2 calculation. This indicates that ORIGEN2 calculation is applicable to the estimation of the amounts of 79Se and 135Cs generated during irradiation. In contrast, the experimentally determined concentration of 99Tc and 126Sn were equivalent to approximately 70% and 60%, respectively, of those obtained through ORIGEN2 calculation.

This content is only available via PDF.
You do not currently have access to this content.