Use of miniature CdZnTe Xγ detector in nuclear safeguards: characterisation of spent nuclear fuel and uranium enrichment determination

The feasibility to perform Xγ-ray spectroscopy, on spent nuclear fuel and uranium solution and pellets, using a Peltier-cooled CdZnTe crystal (9 mm2 sensitive area, 2 mm thickness) coupled with a dedicated preamplifier and amplifier has been studied. In the case of spent fuel, an energy resolution of 5.6 keV at 662 keV is achieved and characterisation of the fuel in terms of burnup and cooling time performed. The good energy resolution at low energies (1.9 keV at 122 keV) has allowed application of the URADOS code which, on the basis of the uranium XKγ-rays. determined the 235U enrichment in the uranium solutions and pellets within 10% of that declared.