from the environmental clean up and remediation. Soil with radiation contamination levels above 1.2 MBq/m2 was placed in 250-litre (66 U.S. gallon) drums and shipped to the Savannah River Plant for burial. A total of 2.2 hectares (5.4 acres) was decontaminated by this technique, producing 6,000 barrels. 17 hectares (42 acres) of land with lower levels of contamination was mixed to a depth of 30 centimeters (12 in) by harrowing and plowing. On rocky slopes with contamination above 120 kBq/m2, the soil was removed with hand tools and shipped to the United States in barrels. In 1968, L Reactor was shut down for upgrades, and, in 1971, K Reactor became the first reactor to be controlled by computer. The site was designated as a National Environmental Research Park in 1972. 1977 saw the startup of the Plutonium Fuel Fabrication (PUFF) Facility. The Savannah River Archaeological Program (SRARP) was established onsite in 1978 to perform data analysis of prehistoric and historic sites on SRP land. Remediation In 1981, an environmental cleanup program began. M Area Settling Basin cleanup began under the Resource Conservation and Recovery Act (RCRA). The heavy water rework facility was closed in 1982. Construction of the Defense Waste Processing Facility (DWPF) began in 1983. Wackenhut Services Incorporated (WSI) began providing security support services at SRP. In 1985, HB-Line began producing plutonium-238 for NASA's deep-space exploration program. The L-Reactor was restarted and C-Reactor shut down. A full-scale groundwater remediation system constructed in M-Area. Construction of Saltstone and of the Replacement Tritium Facility began in 1986. In 1987, DuPont notified DOE that it would not continue to operate and manage the site. The Effluent Treatment Project (ETP) construction began. In 1988, K, L and P Reactors were shut down. An Effluent Treatment Facility began operations to treat low-level radioactive wastewater from the F and H Area Separations facilities. In 1989, the site was included on the National Priority List and became regulated by the EPA. Westinghouse Savannah River Company (WSRC) assumed management and operation of site facilities. The name of the facility changed from Savannah River Plant (SRP) to Savannah River Site (SRS). In 1990, construction of a cooling tower for K Reactor began. Saltstone started operation. In 1991, the mixed waste management facility became the first site facility to be closed and certified under the provisions of RCRA. L Reactor and M Area settling basin were shut down. With