Year
2003
Abstract
ABSTRACT Canberra has performed a radionuclide characterization of a shear-baler - a massive, durable machine used to shear equipment and glove boxes into suitable chunks and compact the chunks into bales of size 16 x 16 inches square and 4 to 10 inches thick. The compacted equipment items were removed from a shut down plutonium fuel fabrication facility. The shear-baler is being retired from service, and characterization data were needed to meet transportation and disposal requirements. The characterization was performed using both gamma ray measurement and neutron counting techniques. The gamma ray measurements were performed using the Canberra In-Situ Object Counting System (ISOCS). Because of the thick, reinforced steel walls of the shear-baler, gamma ray measurements were not usable in some important regions of the shear-baler. Neutron measurements, with their higher transmission through the massive steel structure, were used to augment the gamma ray measurements. Neutron counts were taken using a slab detector and JSR-12 electronics. Totals neutron count rate data were interpreted using a Monte Carlo - Neutron, Photon computer code (MCNP) model of the shear-baler. The neutron emission rate per gram of 239Pu was determined from samples of holdup material cleaned from the shear-baler. The neutron emission rate was expressed in terms of 239Pu for ease of comparison of the gamma ray and neutron measurement results. The measurements were performed in several phases and were used to guide clean out of excess contamination from the shear-baler. The measurement program and analysis are described and results are reported.