Derivation of dose conversion factors for de-control of radioactive wastes of negligible specific activity

Radioactive wastes may be released from legal control if the dose resulting from conventional disposal is negligible for the public. In practice, however, the values for negligible exposures cannot be directly applied for waste disposal purposes. These must thus be converted into values for negligible specific activities which are applicable in terms of measurement, to wastes, that is to say into clearance values. The present report is concerned with this conversion, or more precisely with the deriving of corresponding dose conversion factors. These dose conversion factors are derived on the basis of the assumption that radioactive wastes are disposed of together with domestic wastes on waste tips or through incineration. Typical disposal scenarios have been developed for potential exposures to workers at the waste tip or to members of the public living near to incineration plants. By means of radioecological models, the path of radionuclides from the waste tip via groundwater into the food chain is calculated. The scenarios, model parameters and other model assumptions are discussed with respect to their influence on the calculated dose. Particularly sensitive parameters are investigated with respect to the influence of their variability in real situations on the results of calculations. On the basis of these studies, it can be estimated how reliably the underlying criteria affecting dose can be respected, when the results of the model calculations are applied in normal disposal practice. (orig.)