NEW IN-PLANT HOLDUP COURSE*

This paper will describe a new DOE-sponsored laboratory course on the nondesiructive assay of special nuclear material holdup in a simulated plant situation. The course was presented at Los Alamos for the first time on the days of February 4-8, 1991. The course emphasized gamma-ray spectroscopy techniques and provided three days of laboratory measurements of simulated plutonium and uranium holdup. The laboratory exercises included calibrating detectors for assay of generalized-geometry holdup deposits, followed by measuring holdup in simulated tanks, glove boxes, pumps, piping, and ducts. Attendees worked in two- or three-person teams to measure gamma rays from the simulated holdup, apply corrections to the data, compute the holdup quantities, and compare their results with those of their colleagues and with the known quantities of material hidden in the equipment. The new holdup measurement course was based in part on an earlier DOE Attribute Measurements Course that included 1-1/2 days of uranium holdup measurement exercises. The new course was devoted entirely to holdup measurements and was designed to meet current needs of DOE in this important area. An initial half-day laboratory exercise was provided for new personnel that emphasized the fundamental principles and techniques of gamma-ray spectroscopy. The new course added plutonium holdup measurement exercises, emphasized duct measurment geometries, and concluded with a 1-day workshop (organized by Los Alamos and Rocky Flats safeguards personnel) on measuring holdup in ducts.