Radionuclide content of an exhumed canyon tank and neighboring soil

To assess the long-term hazard potential associated with the burial of partially decontaminated process equipment, burial emplacements of equipment from an irradiated-fuel separations building (canyon) are being exhumed and examined. One piece of equipment a Purex feed adjustment tank that was retired in 1957 from service in a hot canyon at the Savannah River Plant, has been exhumed and studied. Assays of the tank and soil show that only 1 mCi of 137Cs and 0.4 mCi (7 mg) of 239Pu remain on the surfaces of the tank; amounts of these radionuclides in neighboring soil are substantially less. Radionuclides from the contaminated surface of the tank migrated into neighboring soil. Of the three nuclides studied, 90Sr migrated most extensively, as observed previously. 239Pu contents of the tank and neighboring soil were less than the 10 nCi/g total transuranic nuclide content allowed under ERDA standards for burial of nonretrievable waste. Future studies planned include: (1) exhumation of other equipment and (2) in-place lysimeter and laboratory-column tests for studying radionuclidic migration in soil