Year
2017
Abstract
Non-destructive assay is a powerful tool the International Atomic Energy Agency (IAEA) employs to verify adherence to safeguards agreements. Current IAEA veri- fication techniques for fresh nuclear fuel include passive gamma-ray spectroscopy to determine fuel enrichment. This technique suffers from self-shielding and lacks the precision to detect diversion of central fuel rods. The aim of this research is to develop a new, more capable non-destructive analysis technique using active neutron interro- gation of fuel assemblies, and determine the yields of short-lived fission products from high-resolution gamma-ray spectroscopy using high-purity germanium (HPGe). This paper reports results from irradiation of a one meter tall mock fresh fuel assembly with low enriched uranium (LEU) or depleted uranium (DU) rods using a down-scattered deuterium-tritium (D-T) neutron source. Both prompt and delayed gamma-ray spec- tra were collected as time-stamped list-mode data in a coax detector and without list mode data in a planar strip detector. No differentiating signatures were observed in the prompt spectra in either detector; however, both detectors observed several short-lived fission product signatures in LEU and not DU fuel, indicating that this technique has potential for determination of enrichment of fresh fuel assemblies. There were eight unique fission products observed in the LEU spectra with the coax detector spectra, and three fission products were observed in the LEU spectra with the strip detector.