Risk evaluations of transuranic waste at the Idaho National Engineering Laboratory

Approximately 75% of the defense low-level transuranic (TRU) waste stored in the United States and 25% of the buried TRU waste is located at the Idaho National Engineering Laboratory (INEL). Studies have been performed to identify and evaluate technical alternatives for the long-term management of this waste. (The alternatives range from leaving the waste in place as is to reviewing, processing, and shipping it to an offsite geological repository.) Among the evalations that have been performed were preliminary risk evaluations. The dose commitment and risk of hypothetical, near-term, accidental or uncontrolled releases of radionuclides have been evaluated for each alternative. The following potential causes of radionuclide release have been studied: process and handling accidents, shipping accidents, natural events (e.g., earthquakes), man-caused events (e.g., airplane crashes), and future intrusion by individuals or small populations after loss of societal control over the waste. The hypothetical releases have been evaluated, in terms of dose commitment and (if pertinent) probability and risk, for all operational steps making up each concept. The dominant scanerios in terms of near-term risk are (1) lava flow up through or over the waste, leading to airbone releases; (2) an explosion or a criticality accident in the waste-processing facility; and (3) a tornado strike or a fire during waste retrieval. The dominant long-term releases are (1) volcanic action; and (2) intrusion of people on the waste site.Although substantial dose commitments to individual members of the public were calculated for the lava flow and intrusion scenarios, no prompt health effects would be expected from the exposures. The effects would be in the form of a slightly increased likelihood of latent cancer induction