Characterization of transuranic waste from gamma spectroscopy measurements

It is beyond the current nondestructive analysis (NDA) state of the art to accurately measure important alpha- and beta-emitting radionuclides in the presence of typically occurring background levels of neutron and photon radiation associated with remotely handled (RH) transuranic (TRU) waste; in addition, it is not economically feasible to perform destructive analyses that employ radiochemical techniques on representative random samples from each waste container designated for disposal. The methodology presented in this paper combines gamma spectroscopy measurements of waste canisters with radiochemical analyses of smear samples and with statistical analyses to obtain estimates of alpha-emitting radionuclides in waste containers. This approach provides an effective and practical technique for characterization of RH-TRU and TRU radioactive wastes to meet the Waste Isolation Pilot Plant (WIPP) waste acceptance criteria (WAC) and for segregating waste at the Radiochemical Engineering Development Center. Measured activities of easy-to-measure fission and activation products are used to estimate the activities of various alpha emitters, where easy-to-measure implies that the overall measurement uncertainty is < 10%.