Note: Single-source report; awaiting corroboration.
Radioactive liquid waste from chemical separations at the Savannah River Site (SRS) is stored in 51 underground tanks in the F and H Areas. Over 165 million gallons of waste have been generated and concentrated by evaporation to about 32 million gallons currently stored. Of these tanks, eight have been operationally closed, and the rest are undergoing waste removal, cleaning, and closure efforts. Removal efforts prioritize Type I, II, and IV tanks.
In the tanks, insoluble solids settle to form sludge, while the liquid above, known as salt waste, is concentrated by evaporation. This reduces volume and leads to crystallization of saltcake as the solution cools. All tanks are underground with only their tops exposed, and represent four design types. The oldest, Types I and II, feature partial-height steel secondary containment within concrete vaults and use forced cooling systems. Some tanks developed hairline cracks causing minor salt solution leaks into secondary collection pans; waste levels are now maintained below known leak sites and there are no active leaks.
There are twelve Type I tanks, each with a 750,000-gallon capacity; three are closed and grouted, while nine hold about 3.6 million gallons of waste. Five of these tanks have previously leaked into annulus spaces, but currently maintain waste below leak sites. There are four Type II tanks, each with a one-million-gallon capacity; one is closed, and the others together hold less than one million gallons. These tanks have also leaked into annulus spaces in the past, but there are no active leaks at this time.