Experimental Validation of NDA Capabilities for MSR Safeguards - FY2021 Efforts

Athena Sagadevan - Los Alamos National Laboratory
Daniela Henzlova - Los Alamos National Laboratory
Howard Menlove - Los Alamos Nattional Laboratory
Mark Croce - Los Alamos National Laboratory
Material Control and Accounting is a pillar of safeguards that needs to be established and implemented for advanced reactors like the molten salt reactor (MSR) to enable their deployment. The unique features of MSRs mean that new safeguards approaches are required. Additionally, the lack of measurement data on realistic MSR materials is identified as an inherent safeguards need by advanced nuclear industry leaders and safeguards modeling experts. To solve this, experimental approaches and technologies with performance characteristics of relevance for MSR applications are studied within this effort. The focus is on existing and advanced neutron and gamma detection technologies in order to assess their suitability for MSR applications. The goals of this projects are 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 using gamma techniques, and (3) evaluate nondestructive assay (NDA) concepts for harsh, high radiation environments. This presentation will discuss results from the 2nd year of this project, focusing on evaluation of neutron detection technologies. A comprehensive set of neutron NDA measurements were performed at Los Alamos National Laboratory Radiation Instrumentation Calibration Facility (RIC), focusing on validation of neutron detector performance in high gamma background environments using traditional and advanced neutron NDA technologies. 3He detectors, fission chamber and a novel boron-lined proportional counter, the mini High Dose Neutron Detector (HDND) were used to detect neutrons in a presence of gamma-ray backgrounds representative of expected MSR conditions. The miniHDND provides inherent fast signal characteristics, high gamma dose tolerance and the capability of simultaneous neutron and gamma-ray monitoring, hence was chosen as an advanced technology to be benchmarked against other neutron detectors. The measurements performed established individual instruments’ performance limits with gamma doses in the excess of 100 R/h and demonstrated that we can measure neutrons in the presence of gamma-ray backgrounds expected for MSR materials. Future work involves developing a MSR safeguardability concept based on these proposed technologies and additional simulations.