11 Groups Urge Suspension of Nuclear Licensing; Defect Found
A coalition of 11 environmental organizations asked U.S. nuclear regulators to launch an investigation into newly identified flaws in Westinghouse’s AP1000 reactor design, according to an April 21 press release.
The AP 1000 Oversight Group, which includes such organizations as Friends of the Earth, Southern Alliance for Clean Energy, and Nuclear Information and Resource Service (NIRS), asked three federal agencies to suspend the AP1000 reactor from licensing and taxpayer loan consideration. NIRS is an information and networking center for citizens and environmental organizations concerned about nuclear power, radioactive waste, radiation, and sustainable energy issues.
The design flaw is tied to documentation of dozens of corrosion holes being found in existing U.S. reactor containments, which recently has raised concern at the Advisory Committee on Reactor Safeguards (ACRS), an independent arm of the U.S. Nuclear Regulatory Commission (NRC). Containment buildings are vital barriers against radiation releases during nuclear accidents, according to the press release.
“The proposed AP1000 containment design is inherently less safe than current reactors,” said Arnold Gundersen, former senior vice-president at Nuclear Energy Services PCC. Westinghouse did not analyze the scenario for failure containment warned of by Gundersen, the press release stated. "The containment leakage problem is exacerbated because the AP1000 is specifically intended to function as a chimney – to pull air up and release it through the top of the building,” added Gunderson, a 38-year engineering veteran of the nuclear power industry.
In a 32-page technical report Gundersen details a history of holes and cracks found at operating nuclear plants. Such corrosion problems, if coupled with the experimental “passive” emergency cooling feature in the AP1000, could accelerate and greatly increase the early release of radiation during an accident.
Based on the report, the coalition urged NRC Chair Gregory Jaczko to suspend license reviews of 14 proposed AP1000 reactors pending the ACRS investigation. They also urged Secretary of Energy Chu and the White House Office of Management and Budget to drop plans for taxpayer funding for the reactor due to increasing risks of projects failing in midstream. In February, the Obama Administration awarded $8.33 billion in taxpayer-financed loans (with a public guarantee to cover default) to an AP1000 project at Southern Company’s Vogtle plant in Waynesboro, Ga.
Gundersen’s analysis shows that even a three-quarter inch hole in the AP1000 reactor building could, under pressure from a pipe break or other accidents, result in a large and unfiltered radiation release because the building is deliberately intended to move air and heat into the atmosphere during an emergency. That heat removal – via a gap between an inner metal containment and the outer shield building – is the very feature Westinghouse touts as its principal safety upgrade, the press release stated.
Gundersen explained why the probability of a radiation accident is higher with the AP1000: “Existing data shows that containment system failure occurs with moisture and oxygen.” He explained today that for the AP1000 design, leakage from the emergency water tank located above the reactor, testing the tank and/or atmospheric humidity will create, within the gap between liners, “a constant environment of moisture and oxygen that may, in fact, provoke a through-wall containment failure in locations that are difficult or impossible to inspect.”
A number of organizations are contesting design and licensing efforts of 14 AP1000s at seven sites across the Southeast. Also, four AP1000s are under construction in China, with more planned there and in India.
At least 77 instances of containment system degradation have occurred at operating U.S. reactors since 1970. That includes eight through wall holes or cracks in steel containments – two discovered in 2009 – and 60 instances of corrosion that thinned the liner walls below the allowable thickness. In addition to the ACRS, nuclear experts in Europe have recently expressed concern about the likelihood of containment failures at aging plants.
"If Vogtle's proposed new reactors are the flagship of the nuclear industry's claimed resurgence, then everyone needs to pay closer attention because not only are billions of dollars at risk but so is the potential safety of communities living near these proposed new reactors," said Sara Barczak, High Risk program director with the Southern Alliance for Clean Energy.
Although Westinghouse and nuclear utilities such as Duke Energy, Progress Energy and others contend that the AP1000 design was “pre-certified” by the NRC in 2006, in the past two years the NRC has identified design problems involving major components and operating systems, resulting in 18 revisions to the design. Thus, cost estimates for some of the projects have doubled or tripled. Last October the NRC stunned observers by rejecting the reactor building for its potential inability to withstand high winds and the weight of the emergency water tank.