Year
1997
Abstract
In August 1995, the Physical Inventory Plan at the Los Alamos Plutonium Facility required in situ surveys of items in process. The Material Control and Accountability Group, FSS-12, performs these surveys with a variety of hand-held instruments. The in situ surveys were complicated because of high radiation backgrounds, close proximity of the items and the location of the items in glove boxes and tanks. The Advanced Nuclear Technology Group, NIS-6, had developed a lightweight, battery-operated gamma-ray and neutron detection system, NAVI-2, for the Mutual Reciprocal Inspection Treaty with Russia. The NAVI-2 has analysis algorithms that identify 239Pu and also has a small display with a YES/NO detection message. The gamma-ray detector protrudes from the waterproof enclosure in order to accept a tungsten collimator which can isolate a sample of interest from other in-process samples. With the aid of the NAVI-2 and collimator, FSS-12 was able to successfully perform the in situ survey measurements. The NAVI-2 was modified to provide FSS-12 with an instrument that could replace the present suite of hand-held survey instruments. Modifications included a graphic display for gamma-ray spectra, audible search mode, automated calibration, analysis algorithms for nuclear material and medical isotopes, uranium enrichment meter, and spectrum storage and recall.