NRC officials blamed plant operators for allowing the erosion of safety standards that caused the leak to go unnoticed for years. The plant is owned by FirstEnergy Corp., of Akron, Ohio, the company that a U.S.-Canadian government task force said shares much of the blame for the Northeast blackout last August.
The NRC came under fire for not detecting the leak sooner. As a result, regulators have agreed to make changes to its safety and inspection procedures. On Monday, the agency said the plant can safely operate after numerous repairs and changes in management, but environmentalists complained that only 16 of 49 recommended changes in how NRC oversees nuclear power plants have been made.
The NRC will monitor the startup round-the-clock and is assigning three full-time inspectors to the plant. Most nuclear plants have two inspectors.
In addition, NRC will require the plant to undergo an independent inspection each year for five years. The commission's oversight committee will continue to monitor the plant "until we are satisfied that the plant is up and operating in a stable condition," said James Caldwell, regional administrator for the agency's Region III office in Lisle, Ill.
The plant was closed in February 2002 for routine maintenance when inspectors found corrosion on the reactor vessel, where leaking boric acid had eaten almost through a 6-inch-thick steel cap.
FirstEnergy Corp. spent about $600 million for repairs and replacement power while the plant was prevented from producing electricity.
During the shutdown, regulators also found design flaws in Davis-Besse's cooling system pumps, which led to prolonged repairs. FirstEnergy replaced the damaged reactor vessel head, installed a new leak monitoring system and overhauled the plant's management.
The company asked the NRC on Feb. 12 for permission to restart the plant, saying the plant was now capable of being safely operated.