Quantification And Verification Measurements Of U-containing Items Using In-situ Objective Counting System, A Non-destructive Assay Method.

In this work, U-containing hold-up historical items coming from the U reduction process of UF4 to U-metal are quantified and verified using In-Situ Object Counting System (ISOCS) efficiency calibration software, a Non-Destructive Assay method. The items were measured using a portable high purity germanium detector to obtain the isotopic weight, element weight and enrichment. Genie 2000 software was used to collect spectra and the analyses were done using the geometry composer and Genie 2000 analyses sequence. The 235 U masses and the total element weights were determined using ISOCS and Multi-Group Analysis for Uranium (MGAU) was also used to compare with ISOCS enrichment results. The items were estimated to be 46 wt.% enriched in 235 U. The ISOCS results ranged from 40.89 wt.% to 49.29 wt.% and MGAU results ranged from 45.23 wt.% to 48.55 wt.% in 235 U. The enrichment results from ISOCS were comparable with those obtained from MGAU per specific item; the results where within 10 % of each other. The measurements were performed for safeguards accounting purposes and could generally provide a solution to minimize material unaccounted for in process facilities. Keywords: Historical items, ISOCS, MGAU