The Nuclear Regulatory Commission has asked the operators of 11 nuclear reactors across the country, including the two-reactor Beaver Valley Power Station in Shippingport, to fix a computer problem that could allow fuel rods to get too hot during an accident.
The problem, which involves a system developed by Cranberry-based Westinghouse Electric Co., poses no immediate threat to public health or safety, commission spokesman Scott Burnell said. The problem does not affect normal operation of the 11 reactors, which continue to generate electricity.
"We are asking the 11 plants to make sure they've properly analyzed how hot their fuel could get during an accident," Burnell said. "There is an error in the computer code that Westinghouse uses. ... That error could lead to underestimating how hot the fuel could get."
During an accident in which a nuclear reactor lost coolant, fuel rods could overheat, causing them to be damaged and possibly release radioactive material. "We're talking about potential accidents that are very unlikely," Burnell said.
The Beaver Valley Power Station, owned by Akron, Ohio-based FirstEnergy Corp., is aware of the issue and working with Westinghouse to resolve it, spokeswoman Jennifer Young said.
"We are working with each customer to establish what the impact is for each and provide information to NRC to demonstrate compliance," said Scott Shaw, a spokesman for Cranberry-based Westinghouse.
Studies over the past 10 years have shown that nuclear fuel degrades faster than previously thought the longer it stays in fuel rods, said David Lochbaum, director of the nuclear safety project for the Union of Concerned Scientists. As the fuel degrades, its ability to release heat quickly decreases, causing the fuel rod temperature to rise more quickly than previously estimated, he said.
Nuclear plant operators need to be able to accurately predict how fast fuel rods will get to critical temperatures during accidents in which coolant is lost in order to prevent more serious damage to the reactor.
"It's a problem that needs to be fixed ... something that needs to be addressed, but it's not a clear and present danger," Lochbaum said. "The chance of an accident that brings this all into play is pretty remote."
The plants have until March 19 to respond to the NRC.
