Nondestructive verification of the exposure of heavy-water reactor fuel elements

Relative exposures of 137 irradiated heavy-water reactor fuel elements were determined from the measured fission product activities, using high-resolution gamma-ray spectrometry. Exposures ranged from 100 to 1000 MWd/tU. Correlations between various gamma-ray signatures of specific fission products and operator-declared exposure values were calculated. Axial gamma-ray profiles were measured using intrinsic germanium, cadmium telluride, and ionization chamber detectors