Authors:G. Evans, W. Kupferschmidt, R. Portman, A. Palson and G. Sanipelli
The environmental impact of many postulated CANDU (Canada Deuterium Uranium) reactor accidents depends on the behaviour of iodine isotopes. In recent years a substantial portion of Canadian iodine research has focused on experiments conducted in the intermediatescale Radioiodine Test Facility (RFT) at Whiteshell Laboratories. Because of the very low concentrations relevant to reactor accidents, much of the analysis of iodine behaviour has required the high sensitivity of a radiochemical methodology. Very low gas-phase iodine concentrations (<10–10 mol/dm3) are routinely determined, up to several times an hour, using an automated airborne iodine sampler whereas various chemical forms are distinguished using selective adsorbents. Useful information regarding the chemical speciation of iodine in the aqueous phase is obtained using solvent extraction. This paper describes the radiochemical techniques used in RTF experiments, with examples of the results thereby obtained.
Authors:P. Warwick, N. Evans, A. Hall, G. Walker and E. Steigleder
Conditional stability constants have been determined for U(IV) and U(VI) Boom Clay humic acid (BCHA) and Aldrich humic acid
(AHA) complexes, under anaerobic and carbonate free conditions. The constants are needed for nuclear waste repository performance
assessment purposes. The U(IV) constants were obtained by developing an approach based on the solubility product of amorphous
U(OH)4. The U(VI) constants were obtained by applying the Schubert ion-exchange approach.