It is going on two months now and no one knows why Edison International’s California nuclear power plant shut down unexpectedly. That means a special team of federal inspectors will try to get to the bottom of the matter, said officials at the Nuclear Regulatory Commission (NRC).
One of two reactors at the San Onofre Nuclear Power plant in San Clemente, CA, unexpectedly shut down Jan. 31 after critical equipment malfunctioned.
A type of pipe called a steam tube sprung a leak and released small amounts of radioactive steam. At the time, the NRC said the amount of radiation released posed no harm to workers or the public.
Nevertheless, reactor steam tubes must be strong enough to withstand high pressure without rupturing to ensure radiation doesn’t escape the generators that use the steam to produce electricity, the NRC said.
The plant’s other nuclear reactor had been shut down for a scheduled procedure where workers replace the fuel and they inspect equipment. Both units, owned by Edison’s southern California utility and Sempra Energy’s San Diego utility, remained offline.
The NRC said it sent the special inspection team to the plant after the three tubes that leaked failed an important pressure test, which suggested the tubes would probably rupture again.
“We want to make sure we understand the cause of the degraded steam generator tubes and take appropriate actions based on our inspection results,” said Elmo Collins, the administrator of the NRC’s Region 4 office.
During the test, water pumped inside the tube while the pressure inside increased.
The special team includes inspectors from Washington and from the NRC’s Region 4 office in Arlington, TX, which oversees nuclear power plants in western states.