Crews start injecting grout into collapsed Hanford tunnel

SPOKANE — Workers at the Hanford Nuclear Reservation have started injecting grout into a partially collapsed tunnel that contains radioactive waste left over from the production of nuclear weapons, the U.S. Department of Energy said Wednesday.

The grout is intended to improve the stability of the 360-foot-long tube, which dates to 1956, and help prevent any radioactivity from escaping into the environment.

It will take an estimated 650 truckloads of grout to fill the tunnel adjacent to the closed Plutonium Uranium Extraction Plant, which produced most of the plutonium for the nation’s nuclear arsenal, the agency said. The complicated work should be completed by the end of the year.

“There is no question about the difficulty of the work, but we will work safely and methodically to fill up the tunnel,” said Doug Shoop, manager of the agency’s Richland Operations Office.

The roof of the tunnel, which was sealed in 1965, partially collapsed on May 9, forcing about 3,000 workers to shelter in place for several hours.

There were no injuries.

Hanford, which is about 170 miles southwest of Seattle, was built by the Manhattan Project during World War II as the U.S. raced to beat Germany to create an atomic bomb. Hanford made the plutonium for the atomic bomb dropped on Nagasaki, Japan, and went on to make about 60 percent of the nation’s plutonium during the Cold War.

The site now contains the nation’s greatest volume of radioactive defense wastes. Cleanup of the site is expected to last until 2060 and cost $100 billion.

The grout will be injected into the tunnel at night.