Demonstrations of spent fuel storage technology

The demonstration phase for both rod consolidation and dry storage of radioactive wastes is now at its threshold, with the major programs planned to begin in 1984. In order to meet the growing storage needs of the late 1980s, it is important that these programs be productive and remain on schedule. If the storage environment contains air and if the temperature is sufficiently high, then the exposed UO2 may oxidize to U3O8. Because U3O8 is much less dense than UO2, oxidation has the potential for mechanically splitting the cladding and releasing the U3O8. While in the storage container, this offers no immediate safety problems, but it is undesirable as it may complicate future fuel handling and packaging. Because the threshold temperature for air oxidation has not yet been determined for very long-term storage, the early dry storage applications are expected to be in an inert environment. Multiple coordinated R and D projects by NRC, DOE, and utilities are under way to better define the allowable temperature limits for air storage. 2 figures