CL-36 RELEASES FROM THE SAVANNAH RIVER SITE NUCLEAR-FUEL REPROCESSING FACILITIES

Determinations of Cl-36 (T1/2 = 301,000 a) in waters on and near the U.S. Department of Energy's Savannah River Site (SRS) in South Carolina reveal that nuclear fuel reprocessing activities there have released measurable amounts of this radionuclide to the environment. The natural atmospheric flux of Cl-36 at the latitude of SRS is 20-25 atoms m-2 sec-1. Atmospheric releases of Cl-36 from SRS, within the site boundaries, have increased this flux by a factor of at least 10 to 20. Approximately 3 X 10(9) Becquerels (Bq) [84 millicuries (mCi)] of site-derived Cl-36 have been deposited within 200 km of the plant boundaries. By comparison, fallout of Cl-36 from nuclear weapons testing in the 1950s deposited twice this amount of activity in the same area. Surface-water Cl-36, Concentrations in on-site streams represent about 0.01 percent of the Environmental Protection Agency (EPA) drinking-water standard and therefore pose no health concern. At SRS and similar facilities, this additional source of Cl-36 should prove useful for validating ground-water and atmospheric transport models.