Optimization of NDA Measurements in Field Conditions for Safeguards Purposes

摘要

This report describes the results of a field test and evaluation of the Coincidence Collar for PWR fuel assemblies performed at the Franco-Belge de Fabrication de Combustibles (FBFC) facility in Dessel, Belgium from June 10-17, 1981. Comparisons are made with the results using the Prototype Neutron Coincidence Collar at the same facility described in the BLG-548 report. The main results are the following: 1. Active Assay for exp 235 U. The standard deviation for a 1000s run varied from 0.6-0.9%, depending on the type assembly. For longer counting periods, the ultimate precision was about 0.1% for repeat runs with a fixed geometry. The response curve is not saturated and continues to increase versus the enrichment increases through the normal range of LWR fuel. 2. Passive Results for exp 238 U. The counting rates for the passive measurements are much lower than for the active case. The statistical standard deviation was about 1.4% (1000s) but the results were influenced by neutron background variations. (Atomindex citation 13:687635)