[T]ake 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.
“Those lights are out,” said Zander Albert, a control room shift manager. “We’ve shut down those systems.”
That’s just one small example of the ways that the Vermont Yankee site has changed over the past eight months. Corridors are darker and often empty; several buildings have disappeared; a guard shack at the front gate sits unoccupied; and plant administrators, for the first time, have had to worry about a big electric bill.
On a recent tour of the site, Entergy Vermont Yankee spokesman Martin Cohn pointed out the changes. And he emphasized the ways in which Yankee’s physical presence will continue to shrink until, in the not-so-distant future, only two concrete pads holding spent nuclear fuel will remain.
“This is going to be the only active part of Yankee,” Cohn said, sweeping his hand toward the spent-fuel area.
Months before shutting down Vermont Yankee, plant owner Entergy began a “coast-down” in terms of power output. But the company couldn’t make major changes until January, when all fuel was removed from the plant’s reactor.
That made Vermont Yankee a power customer rather than a power generator, and Cohn said the plant site’s January electric bill was about $300,000. The monthly bill has been reduced by more than half as Yankee administrators work to eliminate systems they no longer need.
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.
“A lot of people who had offices inside the protected area now are inside that building,” Cohn said, pointing to the Public Support Building, which lies outside the coils of wire and barriers that mark the plant’s secure zone.
Visitors to the Public Support Building now can cruise through the plant’s front gate without having to stop for a guard. But Entergy administrators say they still have a robust security system in place, and they say anyone who steps or drives onto the plant property is monitored immediately and constantly.
The suspicious behavior of strangers prompts a response from Yankee’s armed security force. That is announced clearly by a large-lettered sign at the front gate, which warns that “unauthorized entry to this property will be treated as a threat to the safety of this facility, its workers and the general public.”
“Security personnel are authorized to use DEADLY FORCE to protect the safety of this facility, its workers and members of the general public,” the sign says.
There are now fewer buildings for Vermont Yankee’s guards to watch, as Entergy has removed seven storage structures inside since the reactor’s shutdown. Inside the protected area, dirt patches and concrete pads mark where those buildings stood.
Cohn said the plant has installed “upgraded technology” for security since the shutdown, and the building removals have helped by “improving the line of vision for security.”
On the technical side of plant operations, there’s still plenty to watch over. The site’s 13 dry casks, loaded with spent nuclear fuel, are “constantly monitored,” Cohn said. They generate enough heat that the air exiting the casks is about 40 degrees warmer than it was when it entered, he said.
While the plant’s control room is quieter these days, personnel keep close watch on things like the pressure inside the reactor building, the temperature of the Connecticut River and the temperature inside the spent fuel pool, which was measured at about 105 degrees during the recent tour.
The 40-foot by 40-foot pool takes on an blue glow under the eerie orange light inside the reactor building. Its water – “perfectly clean, purified water,” Cohn says as he passes by – holds 2,996 spent fuel assemblies, each measuring about 7 inches by 7 inches. “Do Not Linger” signs are a reminder of the material’s radioactivity.
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.
This transfer has happened three times already, in 2008, 2011 and 2012, Cohn said. While members of the public have expressed concerns about the safety of the process – especially given that Vernon Elementary School is situated just 1,500 feet from the reactor building – Entergy has maintained that the transfer is tested and safe.
Throughout the process, “there is no exposure of the spent fuel,” Cohn said. “The spent fuel, from the moment it leaves the pool, is put inside a transfer cask.”
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.
