The River Corridor encompasses 220 square miles of the Hanford Site, including the 300 Area just north of Richland and the nine former plutonium production reactors along the Columbia River in the 100 Area. Cleanup work here focuses on decommissioning, decontaminating, and demolishing facilities, removing contaminated soil and debris from waste sites, and treating groundwater.
Significant progress has been made in these efforts. High-profile cleanup projects along the River Corridor include the remediation of the 100 K Area, the 324 Building cleanup, Interim Safe Storage (ISS) of reactors, and groundwater pump-and-treat operations.
Beginning in 1943 as part of the Manhattan Project, construction started on nine plutonium-production reactors along the Columbia River to facilitate the production of weapons-grade plutonium. By the early 1960s, all nine reactors were operational, but the first reactors began shutting down in 1965. The final reactor shutdown occurred in 1987 after the Cold War. Following these shutdowns, the reactors were deactivated, decommissioned, and their supporting buildings were demolished under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA).
Between 1998 and 2012, six of the nine reactors (C, D, DR, F, H, and N) were transitioned into Interim Safe Storage (ISS) through a process known as “cocooning.” This involved the removal of hazardous materials from the reactor buildings, demolition of adjacent facilities, and sealing of all openings to ensure safe, long-term storage. Among the reactors not cocooned is the 105-B Reactor, the world’s first full-scale nuclear reactor, which was designated a National Historical Landmark in 2015 and is open for tours as part of the National Park Service.
