In situ measurement of residual plutonium

Nondestructive assay techniques were developed and implemented to permit the measurement of residual plutonium in glove boxes, conveyors, and tanks in areas of varying background using both gamma and neutron portable detection equipment. The gamma detector was a 2 x 2 inch sodium iodide detector collimated to view a well defined area. The neutron detector consisted of 3He tubes in a polyethylene case with a small amount of directionality. Application of the described techniques to equipment prior to removal has shortened the clean-up time by identifying the locations of recoverable quantities. The agreement between assigned values and recovered plutonium has been within 16 percent for quantities ranging from several grams up to kilogram levels