Take one look at the pale-green wall covered with white gauges in the Vermont Yankee control room, and it’s clear that the panel hasn’t changed much since the nuclear plant’s origins in the early 1970s.
But there is something new: Blue signs with the word “abandoned” mark the wall, indicating which portions of the plant have been powered off since Yankee’s Dec. 29 shutdown.
Vermont Yankee is heading into SAFSTOR, a period of extended dormancy that precedes the bulk of actual decommissioning work. In essence, the plant is being mothballed, and officials have made repeated references to removing power service so that some sections of the property are “cold and dark.”
“We’re eliminating systems. We’re getting ready to close off water, looking at pipes,” Cohn said. “We’re preparing for SAFSTOR, and a big part of that is reviewing all the systems that are in place.”
In January, Entergy cut the Vermont Yankee workforce from about 550 to 316; and workspaces for remaining personnel have been consolidated. The campus is much quieter as a result.
Getting the spent fuel out of that pool and into more-stable dry cask storage is a major milestone that Entergy expects to reach by the end of 2020. When all spent fuel is finally outside the seven-story reactor building, “that means we can shut it down, and it will be ‘cold and dark,’” Cohn said.
That is no small task, as the current permitting process for a second spent fuel pad at Yankee indicates. The schedule for that process anticipates a certificate of public good from the state in spring 2016, with pad completion anticipated in November 2017.
The existing pad at Yankee hosts 13 dry casks holding 884 spent fuel assemblies. The numbers show how much work remains: There are 2,996 fuel assemblies still in the pool, and Entergy needs 58 casks distributed over two concrete pads to hold all of the fuel at the Yankee site.
Loading and transporting the specially designed, heavy-duty casks is an arduous job. Cohn says it takes about a week to get one loaded cask from the fuel pool to the pad. Casks are loaded inside the reactor building and transferred via rail to an adjacent building where a hulking, tracked vehicle nicknamed Cletus awaits.
At the breakneck speed of 0.4 miles per hour, Cletus – technically called a Vertical Cask Transporter – carries casks to the spent fuel pad, which is situated just a long stone’s throw away.
Because the federal government has not yet developed and approved a central repository for spent nuclear fuel, no one can say how long the fuel will remain on the banks of the Connecticut River.
As long as the material is there, it will require monitoring and security.
It’s a big obligation in a relatively small package: In the end, the history of Vermont Yankee will be boiled down to 58 tall concrete cylinders occupying two slabs – one measuring 76 feet by 132 feet, and the other 76 feet by 93 feet.
“Forty-two years of spent fuel will be on two pads that are less than the size of a football field,” Cohn said.
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