Analyses of Soils from the Commercial Radioactive Waste Disposal Sites at Barnwell, Sc, and Hanford, Wa

Abstract

ABSTRACTBrookhaven National Laboratory, in order to provide technical assistance to the NRC, has measured a number of physical and chemical characteristics of soils from two commercial radioactive waste disposal sites: one at Barnwell, SC, and the other near Richland, WA. Materials commonly used for the containment and the solidification of radioactive waste are subject to underground corrosion. The data reported can be used to assess the corrosivity of each burial environment on a waste form or high integrity container. Samples of trench backfill soil, believed to be representative of the soil that will contact the buried waste forms were collected and analyzed. Earth resistivities were measured at each site. Laboratory measurement of the resistivities of water saturated backfill soils from both sites show values greater than 104ohm-cm. This is indicative of soils having relatively small amounts of soluble ions and of soils likely to be very mildly corrosive to steel. The backfill soil from the Barnwell site is acidic having a pH ∼5. Measurements on Hanford backfill soil indicate a neutral environment; pH ∼7. The exchange acidity of the backfill soils from both sites was <2 meq per 100 g of soil and in most cases an alkaline reaction was observed. The pHs and exchange acidities of these soils are consistent with those of mildly corrosive soils. Aqueous extracts of saturated pastes were used to determine the concentrations of the following ions: Ca2+, Mg2+, K+, Na+, HCO3−, SO4=, and Cl−. The sulfide content of each of the soils was measured in a mixture of soil and an antioxidant buffer solution.