In the 1950s, the Savannah River Plant was constructed across 310 square miles of land on the South Carolina bank the river south of Aiken displacing the residents of several small towns near the Savannah River. The site produced plutonium, tritium, and heavy water for the United States Atomic Energy Commission's nuclear weapons program. The facility is now called the Savannah River Site, and its operator is now the Department of Energy. Three of the site's five production reactors as well as its coal power plant discharged waste heat to the Savannah River via Pen Branch, Steel Creek, and Beaver Creek while two reactors discharged heat to the man made PAR Pond on Lower Three Runs Creek.[1] The Savannah River Plant also produced the majority of the Atomic Energy Commission's heavy water supply by processing water from the Savannah River via the Girdler sulfide process.[2] Heavy water was used as the moderator for the site's production reactors. In 1956 Clyde L. Cowan and Frederick Reines first detected neutrinos with an experiment carried out at the Savannah River Plant P-Reactor.
During their operating lifetimes, the Savannah River Plant's reactors significantly elevated the temperatures several Savannah River tributaries. Since these reactors predate nuclear power generation and were some of the earliest large reactors in the world, this offered unique opportunities for the Savannah River Ecology Laboratory to study the impact of large-scale thermal discharge and other effects of the site's operation. Efforts to remediate the thermal discharge directly to the river, such as the construction of a lake to receive the discharge of L-Reactor [3] and cooling tower to dissipate the discharge of K-Reactor[4] had been recently implemented by the time the reactors were shutdown at the end of the Cold War. The Savannah River Site now extracts tritium, but using targets irradiated at the Watts Bar Nuclear Plant in Tennessee, so the heat discharge associated with tritium production is no longer in the Savannah River basin.
The Vogtle Electric Generating Plant was constructed across the river from the Savannah River Plant, with units 1 and 2 completed in mid 1980s and units 3 and 4 completed in the early 2020s. This plant also requires water from the river, but all four units use large natural draft cooling towers to avoid large scale withdrawals or discharge. The McIntosh Combined Cycle Power Plant and Jasper Generating Station are situated further down the Savannah River which provides feed water for the mechanical draft cooling towers for their combined cycle natural gas plants.