19 Oct (NucNet): The US Nuclear Regulatory Commission (NRC) is carrying out a special inspection at the single-unit Enrico Fermi nuclear power plant in the state of Michigan to review damage to steamline pipes.
On 11 October 2007, during a refuelling outage, plant personnel discovered a small unexpected hole and several indentations on steamline pipes. Under certain circumstances, these pipes would relieve reactor pressure. The NRC said even if the pipes had to be used for this purpose, there would have been no radiation released to the environment.
The plant remains shut down in a stable condition and “appropriate safety systems have been and continue to be available”, the NRC said.
Plant owner and operator the Detroit Edison Company has also been carrying out a review of what caused damage to the pipes. Tampering was initially considered as one of the potential causes and this led the utility to declare an Unusual Event, the lowest level of emergency on the NRC’s four-level emergency classification system.
On 12 October, the utility concluded there was no evidence of tampering and ended the Unusual Event status.
Based on interviews and reviews of maintenance activities, the utility’s preliminary conclusion is that the damage occurred during the removal of pipe insulation.
The NRC’s James Caldwell said the NRC needs to understand how and why there was damage to the piping and “evaluate the plant’s response to the event to gain confidence that such situations will not occur in the future”.
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US Detroit Edison Prepares For Possible New-Build (News in Brief No. 3, 20 February 2007)
