A feasibility study exploring the use of high-pressure xenon (HPXe) detectors for the characterization of spent fuel bundles

The study explored the feasibility of using high-pressure xenon detectors for characterizing spent fuel. The three nondestructive characterization techniques currently in use are the Digital Cerenkov Viewing Device, the Fork Detector and the Safeguards Mox Python (SMOPY) Detector. The Fork and SMOPY detectors typically measure the total gamma and total neutron counts due to the gamma emission from fission fragments and the neutron emission originating primarily from curium. Sometimes high-resolution gamma spectroscopy is also used to determine fission-product ratios. These signatures are compared to signatures predicted by the operator declared values of burnup and cooling time, thereby verifying the operator input. The burnup parameters are then used in burnup codes like ORIGEN to calculate the expected mass of 239Pu, 235U and other fissionable materials. These indirect measurement techniques require detailed knowledge of the operating history of the spent fuel assembly in the reactor. Attention was focused on trying to solve two important problems: (a) designing a method for the detection of missing fuel rods in spent fuel assemblies; and (b), proposing a new direct method for the determination of the Pu content in spent fuel.