Following a 45-day public comment period, the Washington State Department of Ecology has approved a request by the U.S. Department of Energy to temporarily stabilize Hanford’s PUREX Tunnel 2 to prevent the possibility of collapse and the potential release of radioactive contaminants.

Ecology’s action clears the way for federal contractors to immediately begin filling the tunnel with grout (a type of concrete).

The Energy Department this summer asked the state to allow grouting to proceed before the public comment period even started. That request was not approved.

“Communities in Washington state have a right to review and weigh in on important Hanford decisions,” said Alex Smith, manager for Ecology’s Nuclear Waste Program. “We needed to hear from the public to ensure that we made the best possible decision.”

The state held two public hearings on the proposal, and accepted comments through Thursday (Sept. 27). Ecology received more than 70 comments and carefully reviewed them as they came in.

“We’ve received many thoughtful, well-founded criticisms of grouting,” Smith said, “but in the end we must protect Hanford workers, and the surrounding communities and environment. Grout is the best way to ensure the tunnel and its contents are safe until final decisions are made on how to deal with the waste.”

Ecology’s decision allows Energy to grout the tunnel before winter, when weather conditions could make operations more difficult and snow and rain increase stress on the tunnel.

Ecology cited several reasons for allowing the grouting to proceed:

• The tunnel is structurally unsound, and recent photos show corrosion on metal support structures inside. It doesn’t meet engineering standards to support the 8-foot-deep load of dirt on top that serves as a radioactive shield.
• A collapse could result in a release of radioactive contaminants, potentially endangering workers and the environment.
• If the final cleanup decision is to remove the waste, Energy would have to first fill the tunnel with concrete in order to shield workers removing the waste from the  radioactivity.        

This is not the final action on cleaning up Tunnel 2. The process to make those final decisions begins in 2020 and could take several years to complete.

Hanford’s two PUREX tunnels both contain rail cars loaded with radioactively contaminated equipment used to extract plutonium from nuclear fuel rods. A portion of Tunnel 1’s roof collapsed in May 2017 and that tunnel was filled with grout to prevent further collapse. Subsequent reviews and inspections indicate that Tunnel 2 is also at risk of collapse.