Calorimeter Measurements of Low Wattage Items

The transition of DOE facilities from production to decontamination and decommissioning has led to more measurements of waste, scrap, and other less attractive materials. The difficulty that these materials pose for segmented gamma scanning and neutron counting has increased the use of calorimetric assay for very low wattage items (< 250 milliwatts). We have measured well characterized 238Pu oxide ranging in wattage from 25 to 500 milliwatts in the calorimeters at the Los Alamos Plutonium Facility and report the error and the precision of the measurements.