In Vitro Dissolution of Uranium

As part of the recommended procedure for calculating radiation doses from inhaled radioactive material, the ICRP divides radionuclides into three transportability classes on the basis of their dissolution half-times. A method of measuring dissolution rates of uranium compounds in lung fluid using a batch replacement method has been commonly used to determine the transportability class for dosimetry purposes. A report by Stockwell et al however, suggested that the batch replacement technique produced results that varied with the experimental design. Studies are reported of measurements of the dissolution rate of uranium concentrate from an Australian mill and a NBS uranium reference material and the results confirm that the batch replacement method does not produce valid results. The apparent transportability of the uranium is affected by the frequency of solvent replacement. Hence a change in technique will cause a change in the result.