Leach resistance of iodine compounds in Portland cement

Several radioactive iodine isotopes arise from the production of electricity by nuclear power. Most of these are short-lived with half-lives less than a few days and will have decayed to negligible levels by the time the spent nuclear fuel is reprocessed; however, /sup 129/I has a half life of 16 million years. The ultimate objective of any disposal form development project is to find an immobilization system which is prepared easily from the waste products of the recovery processes and will not allow hazardous material release during transport, interim storage, normal disposal, and in the event of a credible occurrence such as groundwater intrusion into the disposal repository. For /sup 129/I the time required for radioactive decay makes achievement of this goal very difficult. In the author's laboratory the authors have examined methods of iodine removal from gas streams, techniques for fixing the iodine in stable solid forms, and methods of disposal. One of the techniques which proved attractive was to incorporate an insoluble, stable iodine compound in a cement matrix. This paper describes the development and leach testing of this system using Portland III cement as the solidification matrix