Characterization of aluminum-uranium core fuels for interim dry storage

Characterization requirements for interim dry, storage of DOE owned, aluminum clad spent nuclear fuels will differ from those for zirconium clad commercial fuels primarily because of the higher potential for degradation in aluminum clad fuels. The post irradiation storage technologies for many of the DOE owned fuels were designed to facilitate a `cooling followed by reprocessing` option that required only short term (months) exposure to the basin water environment. Basin operating practices were therefore predicated on: (a) minimal exposure of the fuel to the basin water, and (b) a lack of significant consequence to minor amounts of corrosion induced degradation of the cladding. The decisions to eliminate, or at least delay, the reprocessing option significantly increased both the time that fuel is exposed to basin water and consequence of cladding degradation. The increased storage times have resulted corrosion induced degradation of the fuel cladding. pitting the galvanic corrosion have in certain cases penetrated the aluminum cladding and exposed core material. Therefore, the potential for corrosion induced damage in the aluminum clad spent fuels in significantly greater than the potential for such degradation in commercial fuels. This increased potential for clad damage must be addressed and fuel characterization needs should bemore » established during the development of interim dry storage requirements and technologies. This paper summarizes metallurgical evaluations and analyses which provide a technical basis that suggest that extensive NDE will not be a prerequisite to the direct placement of a significant fraction of the aluminum dry storage.« less