Characterization of a WESF (Waste Encapsulation and Storage Facility) Cesium Chloride Capsule after Fifteen Months Service in a Dry Operation/Wet Storage Commercial Irradiator.

摘要

After 15 months of service, a Hanford Waste Encapsulation and Storage Facility (WESF) sup 137 Cs gamma source capsule was removed for examination from a commercial irradiator at Radiation Sterilizers Incorporated (RSI), Westerville, Ohio. The examination was conducted by Pacific Northwest Laboratory and was the first study of a sup 137 Cs source capsule after use in a commercial dry operation/wet storage (dry/wet) irradiator. The capsule was cycled 3327 times during the 15-month period with steady-state temperature differences ranging from 70 to 82/degree/C during the air-to-water cycle. The capsule was examined to determine the amount of corrosion that had occurred during this period and to determine if any degradation of the container was evident as the result of thermal cycling. Metallographic examinations were performed on sections that were removed from the inner capsule wall and bottom end cap and the outer capsule bottom end cap weld. The three regions of the inner capsule that were examined for corrosion were the salt/void interface, midwall, and bottom (including the end cap weld). The amount of corrosion measured (0.0002 to 0.0007 in.) is comparable to the corrosion produced (about 0.001 in.) during the melt-cast filling of a capsule. No observable effects of irradiator operation were found during this examination. Consequently, based on this examination, no degradation of WESF sup 137 Cs capsules is expected when they are used in irradiators similar to the RSI irradiator. 9 refs., 12 figs., 2 tabs. (ERA citation 13:054203)