December 2017 - We will review plan to grout Tunnel 2
In fall 2017, a new report from the U.S. Department of Energy indicated that the Tunnel 2 was not built strongly enough to handle the stresses it bears, especially from the weight of eight feet of dirt that forms a shield for the highly radioactive materials stored in the tunnel. The department convened an expert panel to review options to stabilize the tunnel, ranging from a heavy plastic tarp to filling with or poly-foam, and in the end recommended grout. We agreed to the plan to grout Tunnel 1 as the best way to quickly remedy an emergency situation. However, Tunnel 2 is significantly wider, five times longer and has structural deficiencies, but than Tunnel 1. Tunnel 2 also has structural deficiencies, but there is no current emergency.
As of December 2017, we are taking a close look at Energy’s proposal to grout Tunnel 2 before deciding whether we agree that it’s the best solution to protect workers, the community and the environment.
November 2017 - Grouting is complete for Tunnel 1
On May 10, 2017, we took swift legal action to hold the federal government accountable to its obligation to clean up the Hanford site. Within 24 hours, we issued an enforcement order that imposed a series of legally requirements on the Department of Energy.
On June 7, 2017, we approved the U.S. Department of Energy’s plan to stabilize PUREX Tunnel 1 by pumping in grout to encase and cover the highly radioactive materials stored in the tunnel. We agree with Energy that grout – a form of engineered concrete – is the best interim method to safeguard human health and the environment in the event of further collapses. Although we don’t favor grout in all possible Hanford applications, we do endorse its use in this specific case as a way to keep the tunnel safe until a final cleanup decision is made for the waste in the tunnel.
In September 2017, grout started flowing into PUREX Tunnel 1. Hanford contractor CH2M Hill Plateau Remediation Co. awarded a subcontract to a Richland company that has experience delivering grout on Hanford site. The subcontractor went back through the hole created by the early May partial roof collapse in Tunnel 1 to insert grout delivery pipes into the tunnel. Workers then gradually built up layers of grout until the tunnel was nearly filled. That both serves as a shield to reduce radioactive emissions from the waste, and stabilizes the tunnel, greatly reducing the risk from any future collapse.
On November 14, 2017, workers completed the stabilization of Tunnel 1. We’re confident that grouting Tunnel 1 will not interfere with eventual tunnel cleanup and in fact should make that cleanup easier.
On May 9, 2017, U.S. Department of Energy workers doing routine inspections at Hanford Nuclear Reservation discovered the roof had collapsed on Tunnel 1, one of the two tunnels holding highly radioactive waste. They were working around the PUREX (Plutonium-Uranium Extraction) plant when they picked up an increase in background radiation. It wasn’t enough to cause health concerns, but it did prompt them to look for a source. The 20- by 20-foot hole they discovered in Tunnel 1's roof led to an emergency lock-down across Hanford. The lock-down was lifted after a few hours when Energy was confident that no radioactive materials had been released. Fortunately, no one was hurt. Within 48 hours, the hole in Tunnel 1 had been filled with sand, and within a few days the entire length of the 360-foot tunnel had been covered with a heavy-duty plastic tarp, secured on either side with concrete blocks. We’re pressing the Department of Energy to stabilize both of the tunnels.
History of Hanford's PUREX Tunnels
The 360-foot tunnel was built in the 1950s using primarily wood timbers, with railroad tracks running the length. The tunnel is 19 feet wide by 22 feet tall and has about 8 feet of dirt cover on the roof. The tracks run underground from beneath the PUREX plant. When the plant had pieces of broken or obsolete equipment that were too large to break down into containers and bury elsewhere, the equipment was loaded with remotely operated cranes and a remote-controlled, battery-powered locomotive was used to push cars into the tunnel.
Between June 1960 and January 1965, eight flatbed rail cars were loaded and pushed into Tunnel 1. By then, Tunnel 2 was ready. The second tunnel is 1,688 feet long and is built more robustly with steel and concrete. It has the capacity to hold 40 rail cars and currently holds 28. It was in service from 1966 through 1996.
An aging, increasingly vulnerable infrastructure
Hanford is the nation’s largest nuclear waste site, and as the clean-up continues to drag on, infrastructure across the site grows increasingly vulnerable to failure.
Across Hanford, all of the original infrastructure is well past its design life. For example, PUREX Tunnel 1 was built in the 1950s using wooden timbers. It was never expected to be in service nearly 60 years later. Even the newest facilities are past their design life – for example, the double-shell tank that leaked a few years ago was built in the 1970s and is one of the newest waste containers from original site operations.
Under our permit conditions, the U.S. Department of Energy has an obligation to maintain facilities across Hanford so that failures like the tunnel collapse don’t happen, and so they don’t present a risk to the public. The collapse is yet another piece of clear evidence it hasn’t been doing that. We find that failure unacceptable. The weakened structure in PUREX Tunnel 1 has been known for nearly 40 years.