Nuclear Regulatory Commission Says Accident Models Could Be Amiss

Article excerpt

WASHINGTON (CNN) -- The Nuclear Regulatory Commission has asked 11 nuclear power plants for information about the computer models they use to test different accident scenarios, saying those models may underestimate how much nuclear fuel will heat up during cooling system failures.

There is no immediate threat to public safety, said NRC spokesman Scott Burnell, but the commission said an error in the computer models may conceal a problem that could impact public safety in a disaster, such as a major earthquake that destroys the plant's main cooling water conduit.

The NRC's review could result in some nuclear plants being ordered to "dial back" their power-generating capacity to meet safety standards, Burnell said.

At issue is a phenomenon known as "thermal conductivity degradation," or TCD, the NRC said. TCD refers to the fact that nuclear fuel loses its capacity to transfer heat as it ages.

The NRC said it is concerned that some computer models may not account for TCD. …