Chem-Nuclear's Barnwell, South Carolina, waste management facility is the only commercial Low-Level Radioactive Waste (LLRW) disposal facility in America that has operated without regulatory interruption. The 235-acre facility occupies property owned by the State of South Carolina and leased to Chem-Nuclear Systems. The Barnwell Waste Management Facility operates under the authority of Radioactive Material License 097 issued by the South Carolina Department of Health and Environmental Control (DHEC). Since the disposal facility began operation in 1971, about 28 million cubic feet or 90% of the available disposal volume has been used. Many people aren't aware of all the ways we as a society rely on radioactive material to improve our lives, from medical treatments and scientific research to the production of electricity. The LLRW contained at the Barnwell site is the by-product of these essential and sometimes life-saving services. Much of low-level radioactive waste looks like ordinary trash. It consists of contaminated wood, concrete, glass, metal, fabric, paper and resins. All waste accepted for disposal must be in a dry, solid form. No liquid waste is accepted for disposal. No toxic chemical waste or high-level radioactive wastes, such as spent fuel from nuclear reactors, are accepted at the disposal site. Low-level radioactive waste decays relatively quickly to insignificant levels. The rate of decay and the concentration of radionuclides varies widely from one kind of low-level waste to another. Of the waste disposed of at the Barnwell facility, about 90 percent of the radioactivity will have decayed within 100 years after the site closes. A long term care fund is set up and held in escrow by the state to pay for monitoring and maintenace in perpetutity. Prior to disposal, the radioactive waste is sealed inside containers for safe handling and transport. Once at the Barnwell site, these waste containers are placed in concrete vaults located in engineered earthen trenches (disposal cells) excavated up to 30 feet below grade. This method of disposal is called shallow land burial. The principal disposal area is the trench itself. Just as the waste must be in a dry, solid form, the design of the trench, the vaults and the method of filling them keeps the waste dry. By minimizing the contact between the waste and rain water, we reduce the possibility of radioactive materials entering the natural environment. The clay and sand soil of the Barnwell facility have been in place for millions of years. Each trench excavated in this material includes a drainage collection system sloping toward a French drain that leads to a sump. Standpipes allow monitoring of rainwater should it enter the trench. A sand layer covers the bottom of the trench. Technicians at the disposal site place the waste containers in concrete vaults. When a vault is full, its concrete lid is put in place, additional vaults may be placed on top until the vaults are stacked up to three high. Vaults provide long-term structural stability for the completed trench. Backfill around and over the filled concrete vaults consists of sand and soil. Finally, an engineered cap consisting of multiple layers of sand, clay, high density polyethylene and top soil covers the trench area. Shallow rooted grasses planted on top of the cap control erosion. This cap serves as a barrier to help isolate the trench from rainwater infiltration. Since 1991, Chem-Nuclear has installed engineered caps on older, filled trenches at the disposal site. These caps ensure appropriate closure of the trenches and proper management of waste at the site now and into the future. Our Barnwell site is one of the world's most heavily studied and monitored parcels of land. A comprehensive environmental monitoring program includes air, surface water, groundwater, vegetation and soil samples. In addition to an extensive network of monitoring wells both on and off-site, we use an on-site weather station that records wind speed, temperature and humidity, for operational as well as environmental reasons. We're proud of our outstanding record of safely managing the low-level radioactive waste disposal site and also of being a responsible corporate citizen, a good neighbor, and an active participant in the local community.   CHEM-NUCLEAR SYSTEMS 140 Stoneridge Drive :: Columbia, SC 29210 :: (803) 256-0450 Copyright ©1997 Chem-Nuclear Systems. All rights reserved.