Experimental Validation Of NDA Capabilities For MSR Safeguards: First Results

Current molten salt reactor (MSR) safeguards modeling efforts are limited by the lack of measurement data on realistic MSR materials as identified by advanced nuclear industry leaders and safeguards modeling experts. The challenging environment of an MSR where accessibility or direct sampling may be limited or impossible means that rapid, non-destructive characterization of fissile material and waste streams at MSRs is likely to be essential to meet regulatory requirements in a cost-effective way. An advanced systems approach is needed to meet safeguards requirements, and a main component of this approach is validated measurement performance capabilities. The goal of this project is to (1) measure gamma-ray and neutron signatures from nuclear material samples that have characteristics similar to material at an MSR facility, (2) assess limits of rapid anomaly detection and characterization of material compositions, and (3) evaluate nondestructive assay (NDA) concepts for harsh, high-radiation environments. This work will result in a comprehensive set of validated measurement capabilities for safeguards models. We present a systematic approach developed for the evaluation of NDA measurement capabilities and current results from a measurement campaign at Los Alamos National Laboratory focused on traditional and advanced gamma spectrometers. Measured materials from a spent fuel separation process at Argonne National Laboratory were chosen to evaluate limits of quantifying fissile material signatures in the presence of varying concentrations of fission products and actinides. Both high-purity germanium and microcalorimeter detectors are capable of quantifying important nuclides, and each have unique advantages due to efficiency or energy resolution. Results suggest that direct quantification of important actinides in fuel salt may be possible by NDA for a sampling loop in an operating MSR or for salt samples.