VALIDATION OF THE ORIGEN-S CODE FOR PREDICTING RADIONUCLIDE INVENTORIES IN USED CANDU FUEL

The safety assessment being conducted by AECL Research for the concept of deep geological disposal of used CANDU UO2 fuel requires the calculation of radionuclide inventories in the fuel to provide source terms for radionuclide release. This report discusses the validation of selected actinide and fission-product inventories calculated using the ORIGEN-S code coupled with the WIMS-AECL lattice code, using data from analytical measurements of radioisotope inventories in Pickering CANDU reactor fuel. The recent processing of new ENDF/B-VI cross-section data has allowed the ORIGEN-S calculations to be performed using the most up-to-date nuclear data available. The results indicate that the code is reliably predicting actinide and the majority of fission-product inventories to within the analytical uncertainty.