During and immediately following the Second World War, the U.S. Government established large industrial complexes at several sites across the United States to develop, manufacture, and test nuclear weapons. One of these complexes was established in 1950 at the Savannah River Site to produce strategic isotopes, mainly plutonium and tritium, for defense purposes. The site is located adjacent to the Savannah River near the Georgia-South Carolina border (Figure C.1) and comprises an area of about 800 square kilometers (~300 square miles).

The Savannah River Site is host to an extensive complex of facilities that includes fuel and target fabrication plants, nuclear reactors, chemical processing plants, underground storage tanks, and waste processing and immobilization facilities. Plutonium and tritium were produced by irradiating specially prepared metal targets in the nuclear reactors at the site. After irradiation, the targets were transferred to the F Canyon or H Canyon, where they were processed chemically to recover these isotopes. This processing resulted in the production of large amounts of highly radioactive liquid waste, known as high-level waste (HLW), that is being stored in two underground tank farms at the site (in the F Tank Farm and H Tank Farm). The U.S. Department of Energy (DOE) has the responsibility for waste management at the Savannah River Site and has implemented a program to stabilize this high-level waste and close the tank farms.

The information used in this attachment is taken from the documents cited in Attachment E and from copies of the presentations provided at the committee's first information-gathering meeting.

A simplified schematic representation of the HLW system at the Savannah River Site is shown in Figure C.2. This system comprises the following major components:

Waste Concentration and Storage. The high-level waste resulting from operations in the F and H Canyons is currently being stored in 48 underground carbon-steel tanks¹⁶ in the F and H Tank Farms. The tanks range in size from about three million to five million liters (750,000 to 1.3 million gallons). The high-level waste was made alkaline with NaOH before being transferred to the tanks to reduce corrosion of the carbon steel primary containment. Consequently, the waste has a high pH (>14) and a high salt content.

Approximately 400 million liters (100 million gallons) of high-level waste have been produced at Savannah River since operations began in the 1950s, but this volume has been reduced to about 130 million liters (34 million gallons) by removal of excess water through evaporator processing operations. About 10% of the waste by volume is in the form of a metal precipitate, or sludge, that contains most of the actinides and fission products. This sludge was formed by natural settling and by precipitation when NaOH was added to the waste. The remaining waste consists of salt in a solid, or saltcake, form that contains cesium and minor amounts of actinides and other fission products. Salt was produced by processing the alkaline