Hanford officials will not be allowed to start filling a Hanford tunnel holding radioactive waste with concrete-like grout before a public comment period ends.
The Department of Energy had asked the state to issue temporary authorization to start grouting, out of heightened concern that the tunnel could collapse.
But permission now would circumvent a legally required comment period.
DOE wanted the temporary authorization to allow the PUREX plant’s second waste storage tunnel to be grouted, or mostly grouted, before the worst of the coming winter’s weather.
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“We’re striking a balance between the public’s right to comment on this important cleanup decision and the need to secure the waste in the tunnel,” said Alex Smith, manager of the Washington Department of Ecology’s Nuclear Waste Program, a state regulator overseeing Hanford nuclear reservation cleanup work.
After the May 2017, partial collapse of the older and shorter of the two waste storage tunnels, a structural evaluation was done on the second tunnel.
The tunnel built in 1964 holds 28 rail cars loaded with obsolete or failed equipment contaminated with high-level radioactive waste. The waste is left from the past production of plutonium at Hanford for the nation’s nuclear weapons program.
The evaluation concluded the second tunnel also was at serious risk of collapse.
Concerns increased this spring after a video inspection of the highly radioactive interior showed corrosion of bolts and weld plates.
DOE responded by asking to be allowed to proceed with grouting the tunnel, a stabilization method recommended by a panel of experts it appointed.
Tri-Cities mayors also asked the state to skip its public meetings.
The meetings “could potentially delay, as much as a year, the action recommended by the panel of experts, which will reduce the risk to our region of a potentially catastrophic tunnel collapse,” said the letter from the mayors of Kennewick, Richland, Pasco and West Richland.
While DOE says that grouting is the best way to guard against a potential collapse, opponents are concerned that grout would become a permanent solution, according to Ecology officials.
DOE says that that method would encase contaminated items and could be cut out in blocks. Some opponents question whether that could be done and argue that the waste should be removed, according to the Department of Ecology.
“Our highest priority always is safety of Hanford workers and the public, and protection of the environment,” Smith said.
“But we also strongly support the public comment process,” she said. “Once grout starts flowing, the public would no longer have any meaningful chance to affect the decision.”
The state will allow DOE to begin setting up the equipment it would need for the grouting process. Work already has begun to place a mobile grout batch plant for the project at Hanford.
Nearly 5,000 truckloads will be needed to stabilize the tunnel.
DOE has said it wants the grouting done before roads turn icy, particularly since early forecasts predict a unusually wet winter in Eastern Washington.
An usually wet and snowy winter may have contributed to the partial collapse of the first tunnel by soaking the soil and increased the weight on the tunnel’s flat roof.
Hanford officials said they can’t predict how much longer the second PUREX tunnel will be stable.
“It could go another 50 years. It could go another 50 days. I wish I could tell you,” said Doug Shoop, manager of the DOE Richland Operations Office, at a committee meeting of the Hanford Advisory Board last week.
Shoop said if the second tunnel fails, falling steel beams could create a domino effect and possibly puncture waste containers. That could make the airborne release of radioactive material more likely.
No airborne release was detected when the first tunnel partially collapsed. The dirt on top of the tunnel fell in, covering the waste it held on eight rail cars.
The state public comment period started Monday and ends Sept. 27. It follows a DOE public comment period that also was legally required.
Public meetings are set for 5:30 p.m. Aug. 27 at the Richland Public Library and at 6:30 p.m. Sept. 5 at the University of Washington Center for Urban Horticulture in Seattle.
Comments may be submitted on line at http://wt.ecology.commentinput.com/?id=7mped. Or they can be mailed to Daina McFadden, 3100 Port of Benton Blvd., Richland, WA 99354.