Measurement and Calculation of Radon Releases from NORM Residues

Abstract

The mining and milling of uranium ore produce large quantities of residues containing natural decay series radionuclides. Although such residues are relatively small in magnitude compared with those from metal mining and extraction processes, their present worldwide production exceeds several million tonnes annually. In addition, a number of other resource extraction industries (such as phosphate, mineral sands, oil and gas, and coal) produce residues with similar radionuclide profiles. In recent years, these materials have become increasingly interesting from the point of view of radiological impact assessment. There is thus a need to reduce the environmental and health risks from these materials to an acceptable level. In response to the needs of its Member States, the IAEA has for many years supported efforts to publish information on the environmental behaviour of radionuclides. In 1992, the IAEA published Technical Reports Series No. 333 (TRS 333), Measurement and Calculation of Radon Releases from Uranium Mill Tailings, which reviewed the major aspects of radon release, control and monitoring as they relate to the management of uranium mill tailings. Since the publication of TRS 333, a number of developments have taken place in techniques for the measurement, modelling and prediction of radon exhalation, and practical experience has been gained with various residue repositories. It was therefore considered timely to produce a revision of TRS 333 and to expand its scope to include other NORM residues. The present report provides a comprehensive overview of the prediction, measurement and monitoring of radon releases from NORM residues, including uranium mining and milling residues.