Evaluation of methods for immobilizing krypton-85

Three methods of immobilizing 85Kr in solids are evaluated. The methods of immobilization include: (1) high temperature/pressure sorption in zeolites, glass, metal, and other solids, (2) ion implantation/sputtering in solids, and (3) low temperature metal vapor deposition. Each technology is described, and the available data for krypton loading, krypton leakage potential, and heat transfer during storage are presented. The volume and weight of the resulting solids which would be required to store the amount of 85Kr (six volume percent in krypton) which is produced annually by 67 light water reactors (1000 MWe at 27,800 MWd burnup) is given. Based on existing knowledge of loading, leakage, and thermal properties, sorption by zeolites and ion implantation/sputtering by crystalline or amorphous metals appear to be the most promising methods of immobilizing 85Kr prior to long-term storage. Both processes will require further technical development before a conceptual design and cost estimate can be made