An advanced nuclear reactor design, touted for its "passive" safety systems that can operate without human intervention, has been sent back to the drawing board because of safety defects.
The Nuclear Regulatory Commission, which oversees reactor safety in this country, said Thursday that the design of the Westinghouse AP 1000 reactor does not meet federal safety standards and will need to be modified and retested. Seven power companies have applications pending with the NRC to build the new AP 1000 reactors, including Raleigh-based Progress Energy and Charlotte-based Duke Energy.
The design lacks final NRC approval and has not yet been built in this country. But four are under construction in China.
Progress had previously estimated the project cost at $7 billion per each Westinghouse reactor. The company had planned to put the new reactors in operation by 2018 in Florida and by 2020 in this state. But Progress officials say they have not made a final decision whether to build a nuclear reactor or opt for another alternative, such as a natural gas power plant.
The AP 1000 is the reactor selected by Progress for its Shearon Harris nuclear complex in southwestern Wake County and for a site in Florida. Duke Energy is planning to build the reactor in South Carolina.
Billions of dollars are at stake for Westinghouse and armies of contractors that would eventually build new nuclear plants. Westinghouse spokesman Vaughn Gilbert said the company can meet its deadlines and still plans to get the AP 1000 approved by 2011 and have the first one online in this country by 2016.
"We're confident we have the absolute safest design in the marketplace," Gilbert said. "We have not adjusted our schedule."
With planning deadlines approaching, the NRC held a news conference to announce its decision not to accept the AP 1000 as it is currently designed. But Laura Dudes, the NRC's Deputy Director of the Division of Engineering in the Office of New Reactors, characterized the agency's decision as "a relatively routine licensing action."
The AP 1000 reactor was designed to be doused from a giant overhead water tank that can operate automatically several days during a nuclear accident, even if plant personnel flee or die. The tank and supporting structure must be able to support up to 8 1/2 million pounds of water at more than 100 feet above ground.
But the NRC told Westinghouse that the current engineering design lacks the structural stability to withstand earthquakes and hurricanes. The design must also withstand the impact of a commercial airliner.
Current nuclear plants have emergency cooling systems backed by diesel generators that operate a vast array of pumps. The AP 1000 would rely on gravity instead, releasing water from above to keep a nuclear plant from overheating and going into a meltdown.
