Niagara Mohawk Corp., operator of the Nine Mile Point 1 nuclear plant (613 MWe BWR) in upstate New York, decided on 10 May to begin repairing cracks in the reactor’s core shroud. This is despite an inspection indicating the shroud was structurally sound and posed no safety concerns.
The repairs, expected to take five days to complete, were scheduled for the first week in June. They involve installing two clamps over each of the shroud’s vertical welds.
The cracks were discovered during a 1997 refuelling and maintenance outage. The core shroud, a stainless steel cylinder inside the plant’s reactor vessel, surrounds the fuel, directs the flow of water through the fuel bundles and provides support for the fuel assemblies.