SCRIBA, NY – On Saturday, Feb. 18, Nine Mile Point Unit 1 licensed Operators identified increased water leakage inside the drywell. Operators in accordance with their procedures and training, appropriately reduced power at the unit in order to perform inspections to identify the source of the leak.
Personnel subsequently identified a leak on a cooling water system valve. In order to perform the necessary repairs to the valve, the unit needed to be shut down.
The drywell is a steel-reinforced concrete structure with an airtight steel liner that houses a boiling water reactor vessel and associated piping.
The drywell is up to six feet thick in places, and is part of the plant’s primary containment system.
Operators commenced a normal orderly plant shut down in accordance with the procedures and their training and safely shut down the unit on Sunday.
Unit 1 was removed from the grid just after midnight on Sunday, Feb. 19.
The plant is in a stable condition and the issue poses no risk to the public or to plant employees.
“We have assembled the appropriate personnel to investigate the cause of the leak and perform necessary repairs,” said Jill Lyon, spokesperson for Constellation Energy Nuclear Group. “Unit 1 operators will only commence start-up when the required work scope has been successfully completed, post maintenance testing completed and the OCC verified that there are no safety issues preventing restart. Constellation Energy Nuclear Group’s highest value is safety: nuclear safety, public safety, worker safety and environmental safety. As operators of nuclear power plants, our top priority is to ensure the health and safety of our employees and the public.”