Calculation of radioactive waste acceptance quantities for near surface disposal

Available in abstract form only. Full text of publication follows: The inventory of wastes to be disposed can contain a large number of radionuclides. Only some of these radionuclides are significant to radiation dose to individuals and need to be considered in a detailed analysis. A screening analysis was performed to remove the inconsequential radionuclides from the detailed performance assessment of a disposal site. Different methods and models are used for the screening analysis based on specified Trigger Level. The Trigger Level is the criteria specified by the competent authority to form the basis of the safety assessment methodology of the disposal site. A very conservative model of the ground water pathway based on one mSv/y as the maximum annual dose is used as the Trigger Level. The screening method, used for waste inventory calculations, was assessed by the comparison of its results with those published in a draft report by the IAEA. The draft report was concerned with waste acceptance criteria for near surface disposal. These criteria are based on the inverse calculation of safety assessment methodologies. In a previous study, these criteria were assessed through a generic safety study of the disposal site. Owing to the uncertainty reported by the waste generators for the identification and activity of each radionuclide, it is safer to determine the waste inventory, which can be disposed in a specific site. In the present work, Trigger level was used for the calculation of waste inventory for near surface disposal. The results showed different values for the radionuclides studied depending on their half-life and on dose assessment after ingestion. The results obtained represent the maximum conservative inventory values. (author)