1995:19 Non-destructive Assay of Spent BWR Fuel with High-resolution Gamma-ray Spectroscopy

A method, based on high-resolution gamma-ray spectroscopy, has been developed for verification of burnup, cooling time, power history and, to some extent, the initial enrichment of spent BWR fuel. It is shown that, provided that the power history is known and corrected for, bumup and cooling time can be verified with accuracies within 3% and 60 days, respectively, for cooling times up to about 20 years. For cooling times up to about 50 years the corresponding accuracies are 3% and 1.5 years. It is also shown that the above parameters can be determined with no other information than the fuel type. In such cases the accuracies are 3.2% and 170 days, respectively (cooling time <20 years) and 6% and 2 years (cooling time <50 years).