A Comparative Study of Nondestructive Assay Estimates to Chemical Recovery and Operator-Declared Inventory for Large-scale Gaseous Diffusion Process Equipment

Nondestructive assay (NDA) measurements have been conducted at the gaseous diffusion plants in Portsmouth, Ohio, and Pilcaniyeu, Argentina for determination of uranium contained in process equipment. The purpose of these measurements is threefold: (1) support the Portsmouth High-Enriched Uranium (HEU) Suspension Project for safe shutdown of the HEU process equipment, (2) support international safeguards efforts related to the United States/Argentina Cooperative Measurements Program, and (3) validate NDA measurement techniques for inventory verification. The NDA measurement techniques used include gamma-ray scanning, gamma-ray quantification and enrichment evaluation, and passive neutron measurements. The results of these measurements are being compared to chemical recovery and operator-declared values to validate the NDA measurement methods and to refine NDA uncertainty estimates for large-scale gaseous diffusion process equipment.