This spring, an underground train tunnel full of radioactive waste was discovered partially collapsed at the Hanford Site in southeast Washington state. Now, federal contractors are prepping the site to fill the unstable tunnel with grout. They’re planning to start Tuesday night.
Tunnel 1 at Hanford is full of train cars contaminated with radioactive waste. Experts at the site say the best solution is to fill it up with grout—a sort of a thin concrete.
Alex Smith is with Washington state’s Department of Ecology. She’s the head watchdog for Washington on Hanford.
“It actually makes it easier to remove the waste at the end of the day. Because right now it’s really difficult to get highly radioactive, large pieces of equipment out of the tunnel,” Smith said.
“But if it’s encapsulated in grout that helps protect the workers who might be doing the removal," she added. "And when it's encapsulated in that grout it’s more easily cut up by a high-powered wire cutter into small pieces and then you can package those pieces up for shipment offsite.”
But some people have questioned that premise: If you fill the tunnel with grout, can you ever clean it up?
A spokesman with the U.S. Department of Energy said he didn’t have those answers and couldn’t put me in touch any government expert who did.
‘It doesn’t make sense what they’re trying to do’
So what would it take to cut up and haul away the tunnel slab-by-slab?
Vern Balkowitsch Jr. is a demolition expert. He has cut apart complicated stuff, like massive river dams. And he’s not so sure about this plan for the Hanford tunnel.
“It doesn’t make sense what they’re trying to do,” Balkowitsch said with a laugh.
In his shop, Balkowitsch showed off diamond cutting wire. This is what the DOE said they would use to cut up the tunnel.
It looks sort of like a coiled climbing rope, but it has diamond-coated beads strung between spiraled wire and the whole thing is coated in plastic. It cuts like a chainsaw blade attached to a big electric motor.
“So as this is spinning, it’s throwing debris wherever it’s at,” Balkowitsch said. “It’s throwing debris wherever it’s at, all around it—like a sprinkler.”
And that debris is not just chips of concrete.
“No, not chips, it’s grinding,” Balkowitsch said. “It grinds the concrete that’s how it cuts, so then it throws it all over the place.”
And the tunnel contains really contaminated stuff—there’s even plutonium in there.
So, Balkowitsch said, Hanford would have to have some sort of complicated shielding to keep all that dust and slurry away from workers. Maybe even use robots.
Balkowitsch also pointed out that right now the tunnel is covered in nearly 8-feet of sand to protect workers from the radioactive waste. But, as he sees it, to cut the tunnel up—all that sand would have to be removed first.
And then ... the expensive part
Once the tunnel is cut up, it would have to be craned out piece by piece and hauled away with large trucks.
Dickson Company in Tacoma, Washington, is a large-scale demolition outfit. They have helped bring down huge structures like the Seattle Times building, the old IKEA in Renton and they did some work on a reactor at Hanford.
Demian Hinkle, the company’s lead estimator, said running the numbers on demolition is half study, half gut-feeling.
His gut on Hanford’s grout plan for Tunnel 1?
“It’s a lot,” Hinkle said.
Hinkle said Tunnel 1 will have something like 11,000-tons of grout, tunnel debris and the structure itself. To tear all that up would be like when his company demolished the old KING 5 studio on Dexter Ave. in Seattle.
“It was a four story, building made out of reinforced concrete—took up a city block,” Hinkle said.
That means a whole city block, four stories high of concrete would be what the tunnel is underground.
Hinkle said trucking away that contaminated material will likely be one of the largest costs of the project. He said it would probably take more than 400 truckloads to move all that grout and radioactive waste.
That kind of project could take a large demo company like Dickson nearly six months to complete—if it was clean material. But Hinkle said working with contaminated Hanford material would slow down the work a lot more.
And you still have to have a safe place to put it.
Washington’s Hanford watchdog, Smith, has looked at these questions and doesn’t think cleanup will be simple. But she said something has to be done with the tunnel now—or it could collapse further.
“This is the best of the solutions that we saw for Tunnel 1,” Smith said.
Even so, the plan for the cleanup of the tunnel won’t even begin until the year 2020.
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