Workers at the Hanford Site are preparing to start filling the PUREX Plant’s second waste storage tunnel with concrete-like grout as soon as this week, after the Washington state Department of Ecology on Sept. 28 approved the interim stabilization work to prevent collapse.
In May 2017, there was a partial collapse of the older and shorter of the two tunnels storing railcars loaded with failed and obsolete equipment contaminated with radioactive waste. That tunnel was quickly grouted under emergency conditions with no public input.
The Department of Ecology, a Hanford regulator, ordered a structural review of the second tunnel after the collapse at the first tunnel. The second tunnel, which is 1,700 feet long and holds 28 railcars, was also determined to be at risk of collapse. Concerns increased this spring when a video inspection of the interior found corrosion in steel beams and in bolts used to anchor the beams to concrete arches.
The Energy Department asked the state to waive the public comment period so it could start grouting as soon as possible, which it said was early September. The Ecology Department refused to waive the public comment period, but permitted DOE to start preparing for grouting – warning that it would do so at its own risk since there was no guarantee that stabilization approach would be approved.
“Communities in Washington state have a right to review and weigh in on important Hanford decisions,” Alex Smith, manager of Ecology’s Nuclear Waste Program, said on Sept. 28. “We need to hear from the public to ensure that we made the best public decision.”
She said the state agency received about 70 comments, all of which were immediately reviewed. “In the end we must protect Hanford workers, and the surrounding communities and environment,” Smith said. “Grout is the best way to ensure the tunnel and its contents are safe until final decisions are mad on how to deal with the waste.”
At the start of this week Seattle-based Hanford watchdog group Heart of America Northwest said it expected to appeal Ecology’s decision in an effort to stop the grouting. The organization has 30 days to file an appeal with the Washington state Pollution Control Board. The group criticized the state decision, saying it should have taken longer to consider public input, including 10 pages of comments Heart of America Northwest submitted on the final day of the comment period. The group’s executive director, Gerry Pollet, called it “the most outrageous and insulting disregard of public comment in the sad history of Hanford cleanup.”
Pollet sent a letter Monday to Washington Gov. Jay Inslee asking him to override Ecology’s decision to allow grouting. The governor’s office released a statement on Wednesday saying that it supported the grouting decision “to ensure that the tunnel is stabilized, workers and communities are protected, and we don’t have another collapse.”
Heart of America said stabilizing the second tunnel is not an emergency and could make it impractical or impossible to remove and dispose of waste in the tunnel when a final cleanup decision is eventually made. The railcars likely hold some high-level radioactive or transuranic waste that should go to a deep geological repository, according to the group. Heart of America said other, less permanent methods should be considered to stabilize the tunnel. They could include covering the tunnel with a tent or filling the end of the tunnel where corrosion was found with sand, which would be easier to remove than grout.
The Energy Department has said that if it eventually decides to remove the grouted waste, the material could be cut into large pieces accounting for the location of the railcars. The process to make final cleanup decision on the tunnels and other central Hanford sites is scheduled to begin in 2020 and could take several years to complete, according to Ecology.
“The tunnel is at high risk of collapse,” DOE said in a statement on Sept. 28. “Grout placement will protect workers, the public and the environment, while not precluding future options for disposition.”
Contractor CH2M Hill Plateau Remediation Co. has set up grout batch plants near the tunnel and installed equipment into six risers at the top of the tunnel where grout will be poured in to form layers an inch or two thick until the tunnel is filled.
The Department of Ecology said it allowed grouting because the tunnel is structurally unsound and does not meet engineering standards to support 8 feet of soil on its top. The soil is needed to provide radiation shielded. “A collapse could result in a release of radioactive contaminants, potentially endangering workers and the environment,” Ecology said in a statement. If the final cleanup decision is to remove the waste, it will need to be filled with concrete to shield workers from radioactivity as they remove the waste, it said.
