Condenser tube leak causes reactor to reduce power
MONTPELIER, Vt.—A leak of Connecticut River water into the Vermont Yankee nuclear plant's cooling system has prompted the reactor to reduce power by more than half while repairs are made, a spokesman said Tuesday.
Vermont Yankee spokesman Robert Williams said crews were setting up Tuesday to determine which of some 22,000 "condenser tubes" had sprung a leak and would have to be shut down and removed from service.
The 650-megawatt reactor in Vernon, in Vermont's southeast corner, reduced power to 45 percent of normal and was expected to remain at that level for several days, Williams said.
"The reduction in power down to about 45 percent allows for the isolation or closing of one of four condenser waterboxes to perform the maintenance and to maintain a safe working environment for the workers performing the task," Williams said in an e-mail.
He said condenser tube leaks were common at nuclear and other power plants that use steam to power a turbine making electricity.
Williams said the fix is simply plugging the leaking tube and taking it out of service, adding that the plant was built with many extra condenser tubes -- he couldn't say how many. He said about 800 of Vermont Yankee's tubes had been taken out of service previously; most weren't leaking, but failed inspections during refueling outages, he said.
"This is the kind of thing we've done periodically through the life of the plant," Williams said.
Williams and Neal Sheehan, spokesman for the federal Nuclear Regulatory Commission, said the plant needs to maintain purity in the steam that travels between the reactor and the turbine, and that river water leaking into the system is something that needs to be addressed quickly when it's found.
"They're doing the right thing," Sheehan said. "They're going to reduce power so they can go in and look at the leakage and fix it promptly."
He said the concenser system was pressurized to ensure that no steam from inside it, which he called "slightly radioactive" would leak out to the river.
