Tank 41H bounding uranium enrichment

摘要

The intent of this document is to combine data from salt samples and historical process information to bound the uranium (U-235) enrichment which could be expected in the upper portion of the salt in Tank 41H. This bounding enrichment will be used in another document to establish a nuclear safety basis for initial salt removal operations. During the processing period of interest (4/82-4/87), waste was fed to the 2H Evaporator from Tank 43H, and the evaporator bottoms were sent to Tank 41H where the bottoms were allowed to cool (resulting in the formation of salt deposits in the tank). As Tank 41H was filled with concentrate, the supernate left after salt formation was recycled back to Tank 43H and reprocessed through the evaporator along with any additional waste which had been added to Tank 43H. As Tank 41 H filled with salt, this recycle took place with increasing frequency because it took less time to fill the decreased volume with evaporator concentrate. By determining which of the sampled waste tanks were receiving fresh waste from the canyons at the time the tanks were sampled (from published transfer records), it was possible to deduce which samples were likely representative of fresh canyon waste. The processing that was being carried out in the Separation canyons when these tanks were sampled, should be comparable to the processing while Tank 41H was being filled. (ERA citation 19:033892)