MONTPELIER, Vt. — Unplanned shutdowns an hour apart at nuclear plants in Vermont and New York – one due to a small leak of radioactive water inside the plant, the other due to a transformer explosion – show the challenge of managing aging nuclear plants, an expert said.
Both plants are 38 years old and owned by New Orleans-based Entergy Corp. No one was hurt at either plant and each was expected to be back online quickly.
In Vermont, Entergy determined that the source of the leak was a 2-inch metal access plug on a pipe that had been welded over in 1972. The pipe was part of a closed-loop system that feeds water to the nuclear reactor, where it is heated and then sent to spin turbines that make electricity, said plant spokesman Larry Smith.
The weld was leaking about 60 drops a minute, he said. Repairs were expected to take 24 hours, he said.
It was too soon to tell what had caused the transformer explosion Sunday at the Indian Point 2 reactor, a plant north of New York City that was built in 1972. No one was hurt and no radioactive material released. The explosion happened outside the nuclear portion of the plant.
David Lochbaum, director of the nuclear safety program for the Union of Concerned Scientists, said both problems were probably due to their age. As plants get older, they face more and more such challenges, said Lochbaum.
The Nuclear Regulatory Commission called the two shutdowns a coincidence and said agency inspectors were monitoring the repair plans at the Vermont Yankee plant in Vernon and at Indian Point 2, where a spare transformer was on site.
Transformer explosions happen, on average, about a half dozen times a year at U.S. nuclear power plants, Lochbaum said.
The transformer explosion may trigger closer scrutiny from federal regulators as Entergy tries to win a new license.
The Nuclear Regulatory Commission imposes extra scrutiny when a plant averages more than three unplanned shutdowns per 7,000 hours of operation, and Entergy spokesman Jerry Nappi said there had been three such shutdowns since January. The NRC would check to see if the plant is over the limit, NRC spokesman Neil Sheehan said.
The leak is the latest problem for the Vermont Yankee plant, which has been beset with technical problems.
In January, officials announced that tritium, a radioactive isotope of hydrogen that has been linked to cancer when ingested in large amounts, had turned up in a test well on plant's property. Later, other radioactive substances were found in groundwater and soil. Also in January, legislators learned that Vermont Yankee personnel had misled them and state regulators by saying Vermont Yankee did not have the type of underground piping that would leak tritium.
In February, the state Senate stopped regulators from issuing a state license for Vermont Yankee to operate after 2012, when the plant's current state and federal licenses expire.
Associated Press writer Jim Fitzgerald in White Plains, N.Y., contributed to this report.