The Impact of Increased Requirements for Verification Measurements of Category III and IV Receipts

Abstract

As part of the regular nuclear material accounting and control process, sites that possess accountable nuclear material are expected to regularly perform measurements of the material. The expectation for the type of measurements and their frequency is set out in US Department of Energy (DOE) Order 474.2, and further detailed in each site's respective material control and accountability (MC&A) plan and associated controlling documents. The measurements of interest in this report are those performed on external (i.e., between DOE sites) transfer receipts of Category III or Category IV accountable materials. In 2020, a revision of DOE Order 474.2 was proposed that would significantly increase the requirement that measurements be performed upon receipt of material, and that those measurements be quantitative verification (rather than qualitative confirmatory) measurements. A survey was performed of DOE sites to discuss the impact on their MC&A measurements program if more rigorous verification measurements requirements for Category III and IV receipts were implemented. An assessment of nondestructive assay (NDA) measurement instruments to meet those needs was also performed. Sites across the board indicated that personnel and budget would have the greatest effect. Sites qualified as Category I and Category II indicated a reduced impact because these sites already have the measurement capabilities and some personnel but would require additional measurement systems. Category III and Category IV sites indicated a much larger impact because these sites generally have smaller MC&A programs. Some smaller sites stated that a measurement program would need to be created to handle the demand. Calorimetry, quantitative gamma spectroscopy, and neutron coincidence counting systems were identified as common systems that could meet the verification measurement requirements. Additionally, calibration standards for the calorimetry and neutron coincidence counting systems are also needed. A comparative study should be performed for the In-Situ Object Counting System (ISOCS) and ISOTOPICS, along with performing a qualification of a commercial-off-the-shelf (COTS) calorimetry system, and development of an active well coincidence counter (AWCC) system that uses a neutron generator.