River Corridor Cleanup
Protecting the Columbia River and Restoring Hanford’s Natural Buffer
The River Corridor spans over 220 square miles along the Columbia River, covering the 100 Area—home to Hanford’s original nuclear reactors—and the 300 Area near Richland.
Cleanup activities in this region focus on:
Decommissioning, decontaminating, and demolishing former facilities
Removing contaminated soil and debris from legacy waste sites
Treating groundwater to protect the river and surrounding ecosystems
Progress & Priorities
Significant headway has been made in cleaning up the River Corridor. Key accomplishments and ongoing efforts include:
100 K Area remediation
Cleanup of the 324 Building, a high-risk structure near Richland
Interim Safe Storage (ISS) of reactor buildings
Pump-and-treat systems for groundwater remediation
A Legacy of Production, A Future of Protection
The River Corridor holds the earliest history of Hanford’s operations. In 1943, as part of the Manhattan Project, construction began on nine plutonium production reactors along the Columbia River. By the early 1960s, all nine reactors were operational.
As the Cold War ended, the first reactors began shutting down in 1965, and by 1987, all nine had ceased operations. What followed was decades of work to safely close and clean these historic facilities.
Interim Safe Storage: Cocooning the Reactors
Between 1998 and 2012, six of the nine reactors—C, D, DR, F, H, and N—were placed into Interim Safe Storage (ISS) using a method known as “cocooning.” This process included:
Removing hazardous materials
Demolishing support buildings
Sealing all openings for safe, long-term containment
Preserving the B Reactor
The 105-B Reactor, the world’s first full-scale nuclear reactor, was preserved due to its historical significance. In 2015, it was designated a National Historic Landmark and is now open for public tours as part of the Manhattan Project National Historical Park, managed by the National Park Service.