Tell me more about the Interim Waste Containment Structure (IWCS) at the NFSS?
The 10-acre interim waste containment structure (IWCS) on the NFSS property contains more than 250,000 cubic yards of radioactive residues, wastes, and contaminated soil and debris from the previous waste consolidation effort of the U.S. Department of Energy (DOE). Of greatest concern are the 4,000 cubic yards of high activity K-65 residues which contain an average of 520,000 pCi/g of radium-226 that are contained in the IWCS. Radium-226 has a long half-life of 1,600 years and decays by emitting an alpha particle to radon-222, a gaseous radionuclide. The K-65 residues were placed in the foundation of a former freshwater treatment building and are covered by over 129,000 cubic yards of low-level contaminated soils and an interim cap. The interim cap consists of three feet of compacted clay, topped by one foot of fill and six inches of topsoil. The IWCS was designed and constructed to safely contain the radioactive materials for a period of 25 to 50 years. The IWCS cap was installed in a
