Leak fixed, Yankee at full power
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By Susan Smallheer Herald Staff - Published: January 12, 2009
BRATTLEBORO — The Vermont Yankee nuclear plant was back up to 100 percent power Sunday after Entergy Nuclear workers completed repairs to a radioactive leak in the reactor's feedwater system.
The source of the small leak was traced to a faulty weld in a 10-inch wide test port off the 24-inch feed pipe, according to Entergy Nuclear spokesman Robert Williams. Williams said that the "weld defect" was an original weld in the 37-year-old reactor. He said that the company didn't know what caused the weld to suddenly start leaking.
Williams said Sunday the repairs had been completed sometime late Friday, and the reactor was at 49 percent power Friday evening, 75 percent power Saturday morning and reached 100 percent power Saturday night, delivering 620 megawatts of power to the New England power grid.
Williams said Entergy Nuclear had launched an investigation to test other similar welds like the one that sprung the leak, discovered Thursday morning during routine inspections.
"We have confidence that that will identify any other problems," he said.
Neil Sheehan, a spokesman for the Nuclear Regulatory Commission, said the original testing portal had been designed and located into the section of the feedwater piping, which was used for radiography during initial construction of the plant.
He said the weld is in the cap on the portal, not the pipe itself.
"As usual, our resident inspectors are closely observing the company's work on identifying the source of the leak and its repair plans," he said, adding that they would also be monitoring the repair on the valve gasket in the reactor water cleanup system.
Williams said he didn't have information yet on the condition of the pipe and the weld where the leak developed. He said the insulation that was removed to identify the location of the leak had been dried and returned to the piping.
He said the other radioactive leak that was disclosed last Wednesday would now be repaired, sometime this week.
That leak is in the cleanout system for the reactor water. The company is bringing in a specialist to isolate that leak, which was leaking about 2-1/2 gallons a minute, compared to the "60 drops a minute" for the feedwater leak.
The bigger leak, which was discovered about two weeks ago but only disclosed by Entergy last Wednesday, was traced to a faulty metal gasket in a valve on the cleanout system. The company said the leak and its repairs wouldn't require the plant to shut down or reduce power production.
On Friday, Central Vermont Public Service Corp. spokesman Steve Costello estimated it cost the utility $100,000 a day in replacement power for every day Yankee was at reduced power.
Yankee had been brought down to 40 percent power Thursday afternoon to accommodate the second leak, which despite its size was deemed more serious by the company.
Contact Susan Smallheer at susan.smallheer@rutlandherald.com.
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