Year
2009
Abstract
The Los Alamos National Laboratory (LANL) supports the International Atomic Energy Agency (IAEA) by providing training for IAEA inspectors in neutron and gamma-ray Nondestructive Assay (NDA) of nuclear material. Since 1980, all new IAEA inspectors attend this two week course at LANL, gaining hands-on experience in the application of NDA techniques, procedures and analysis to measure plutonium and uranium nuclear material standards with well known pedigrees. As part of the course the inspectors conduct an inventory verification exercise. This exercise provides inspectors the opportunity to test their ability to perform verification measurements using the various NDA techniques. The verification of an item by an inspector is based on whether the measured assay value agrees with the declared value to within three times the historical delta value. The historical delta value represents the average error from previous measurements taken on similar material with the same measurement technology. If the measurement falls outside a limit of three times the historical delta value, the declaration is not verified. This paper uses measurement data from several years of IAEA courses to calculate a historical delta for four non-destructive assay methods: Gamma-ray Enrichment, Gamma-ray Plutonium Isotopics, Passive Neutron Coincidence Counting, and the Neutron Coincidence Collar. These historical deltas provide information as to the precision and accuracy of these measurement techniques under training conditions.