Year
2000
Abstract
The Crated Waste Assay Monitor (CWAM) system was designed at Los Alamos National Laboratory to address safeguards and waste measurements issues at the Oak Ridge Y-12 Plant. CWAM utilizes the differential dieaway technique (DDT) to measure 235Ucontaminated waste inside B-25 waste crates. The performance objectives for CWAM were twofold: (1) ensure large quantities of material do not leave the Y-12 Plant via waste boxes, and (2) measure fissile contamination at levels as low as the Tennessee landfill limit of 35 pCi/g. This paper begins with a history of the CWAM project describing the motivation for the redesign effort, original goals set for the project, and the design choices made to achieve these goals. The remainder of the paper presents experimental results from a matrix calibration study that included both passive and active assays on three hydrogenous matrices, two B-25 crates and one SWB, and one metallic B-25 crate. The reduction in spatial variation with multiple interrogation positions for each of the surrogate matrices is shown. Sensitivity values for these matrices are also given both in terms of 23sU mass (g) and activity concentration (pCi/g).