Inside the Vermont Yankee nuclear power plant
04/12/04 12:00AM By John Dillon
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(Host) For the rest of the month, the Vermont Yankee nuclear plant will be shutdown for a major overhaul. Over a thousand people are working around the clock to install new equipment so the plant can boost its power by 20 percent.
Yankee officials say the upgrade is a relatively low-cost way to gain an additional 110 megawatts. But opponents worry that safety will be compromised as more power is squeezed out of the aging, 32-year-old reactor.
VPR examines this issue in a two-part series. Today, reporter John Dillon takes us inside the Vernon power plant.
(Dillon) The Yankee nuclear plant is a now a huge construction site. Eleven-hundred workers go through these gates and pass through a rigorous security screening. Private security guards wearing black uniforms and carrying automatic weapons check IDs. A machine puffs air over each worker and then sniffs for hidden explosives.
Once inside, dosimeter badges are required to detect radiation.
"So here we go. As soon as it's green you've got to go." (Clanking sound) "Perfect, you're in. We've still got to go down to dosimetry to pick up the self-reading dosimeters."
(Dillon) Last month, state regulators allowed Vermont Yankee to install the equipment needed for the increase in power. Entergy, the Louisiana company that owns Yankee and nine other reactors, still needs approval from the U.S. Nuclear Regulatory Commission.
But under the federal rules, it can start the work now. So Entergy is betting the $60 million cost of the upgrade that it will win federal approval next year, after the equipment is installed. It's probably a safe bet. The NRC has reviewed more than 90 previous upgrade requests, and rejected none of them.
"Now you've entered what we call the radiation controlled area..."
(Dillon) Craig Nichols, the manager of the project, leads me through the reactor building. A nuclear power plant harnesses a controlled chain reaction from radioactive uranium to generate heat. The heat boils water and the steam from the water spins a turbine, which in turn drives a generator to produce electricity.
To get the 20 percent power boost, the reactor needs to generate more heat and send more steam through a new turbine. It's this higher temperature and pressure that critics worry could weaken the plant and compromise safety. Nichols says key components will be replaced.
(Nichols) "We'll walk all the way down to the front of the turbine and over here, and you'll see the new high pressure turbine that we're putting in. That's another power uprate modification that actually allows the 20 percent more turbine to make more power. Nice shiny new high pressure turbine."
(Dillon) But to produce more power, about 20 percent more fuel will be consumed.
(Nichols) "As you can see down there - without going over - this is our spent fuel pool. This holds all our fuel since first starting up..."
(Dillon) Thirty-two years worth of old fuel rods are stacked here under water that reflects a pale blue light. The tank is smaller than a swimming pool, but much deeper - about 40 feet deep. And it's running out of room.
(Nichols) "We have 368 fuel assemblies in this reactor. Normally we would replace approximately 100. When we do this refueling for the purposes of power uprate, we'll have to replace approximately 20 more each time."
(Dillon) The spent fuel remains highly dangerous for thousands of years. Yankee plans to store the excess waste in dry concrete casks on site until a permanent repository is built in the Nevada desert. Opponents of the power boost have focused on the fuel issue. They say it doesn't make sense to produce more waste, which could become a target for terrorists, without a safe or permanent place to put it.
The critics have also challenged the overall safety of the project. They point out that Yankee would be the oldest plant to undergo the largest-ever power upgrade, and that it's exempt from some newer federal safety standards. And they argue that the power increases have led to shutdowns at other nuclear plants.
Outside the plant, the issue is hotly debated. During a recent Switchboard on Vermont Public Radio, Peter Alexander, director of the New England Coalition that opposes the Yankee upgrade, challenged plant spokesman Brian Cosgrove.
(Alexander) "Of these eight plants that Brian has cited that have received large uprates, five of them according to our information and the reports that we're seeing from the NRC, five of them have experienced serious uprate-related breakdown of one sort or another."
(Dillon) Vermont utility regulators also focused on the reliability question. Since replacement power is more expensive than Yankee's, the state Public Service Board recently pointed out that extended shutdowns at Yankee could bring financial harm Vermont ratepayers.
Back at the plant, Yankee executive Craig Nichols says each retrofit is different and that Yankee has learned from the ones that have gone before. He says that the upgrade allows Yankee to install new and safer equipment.
(Nichols) "We're making some of the components thicker, and adding some bracing, so under increased power operation we won't get a vibration that could cause a problem that they did at some of the other plants. Those plants did not do those modifications in advance. We've learned from that and are making these pre-emptive modifications."
(Dillon) The scale of the work here is enormous. Overhead, a 140-ton crane stands ready to lift the main piece of the generator out to a railroad car. From there, it will be shipped to Brattleboro for rebuilding.
The boost in power production will also cause a slight increase in radiation that leaves the plant. If the levels exceed state limits, Yankee will be required to install additional shields or reduce power. The 1,100 people who work here are all checked for radiation. Two machines scan for signs of exposure:
(Mechanical voice) "Right hand, left hand, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1 - please go back! (Nichols) "Oh, go back."
(Dillon) Visitors are also checked. And there's a delay as the last machine warns of contamination as I walk through. After a morning inside the plant, even my microphone has picked up some faint radioactivity. Yankee officials assure me that the levels are safe. And after a few minutes for the particles to decay and disperse, the device flashes the green light, and we're free to go.
For Vermont Public Radio, I'm John Dillon in Vernon.
In Tuesday's story, VPR examines whether federal regulators have weakened a key safety standard in their review of the project.