Nondestructive determination of burnup and cooling times of irradiated fuel assemblies

The applicability of nondestructive gamma-ray and neutron techniques for the characterization of irradiated fuel assemblies has been investigated. Consistency of relative cooling times can be verified using specific isotopic ratios. The axial activity profiles of assemblies have been measured using a variety of detectors. Declared burnup values for MTR, BWR, and PWR assemblies have been correlated with the /sup 134/Cs//sup 137/Cs and /sup 154/EU//sup 137/Cs isotopic ratios.