Preliminary investigations into optimizing detector configuration for nondestructive assay of fresh nuclear fuel

Like other components of the nuclear fuel cycle, fresh nuclear fuel has potential safeguard and security concerns. Non-destructive assay (NDA) measurements need to be examined and made available to nuclear industry partners to decrease safeguard and oversight concerns for nuclear power plants and facilities. This study analyzed four proposed evaluation criteria: quantity of detectors required, speed and accuracy of detector verification, overall efficiency of neutron and gamma detections, and suitability of observables to advanced machine learning algorithms. Four different detectors have been arranged to be evaluated simultaneously: four Saint-Gobain ³He proportional counters, an Eljen EJ-309 liquid scintillator, a Saint-Gobain / Bicron NaI(Tl) scintillation detector, and a Cs₂LiYCl₆:Ce³⁺(CLYC) scintillation detector. Mock-up BWR and PWR fresh fuel configurations were developed by creating 4x4 and 3x3 natural uranium assemblies and aided in assessments for detector configurations. Additionally, ²⁵²Cf was included to increase the number of neutrons for evaluation. The results of this work will be used to develop a versatile, multi-detector system for fresh fuel verification. The exploration of detector types, data modalities, and their significance as input for advanced machine learning and data analysis algorithms is being explored to understand the obstacles and opportunities in the development of a consolidated low-cost, commercial-off-the-shelf system that nuclear power plants, facilities, and/or inspectors can use for non-destructive verification of fresh nuclear fuel and assembly templating for quick nuclear material inventory verification.