The U.S. Nuclear Regulatory Commission (NRC) is expected to vote this year on the first of two construction permits; the most advanced is Southern Company’s proposal to build two new reactors at its Vogtle, Georgia, nuclear power plant. Southern has conditional approval for an $8.3-billion federal loan guarantee to backstop its financing and has broken ground at the site.
Meanwhile, Rep. Edward Markey (D-Massachusetts) has been critical of the NRC’s decision-making on the Westinghouse AP1000—the reactor design for half of the 28 reactors proposed in the U.S., including Southern’s. Markey sent a letter to the NRC last week criticizing its plan to approve the AP1000 this spring or summer despite a dissenting opinion from one of its senior engineers, who has raised doubts about the earthquake hardiness of the AP1000’s concrete-steel hybrid containment building.
The earthquake concerns, ironically, undermine confidence in the passive safety system designed to make the AP1000 less vulnerable to the power blackout that sparked the Japanese crisis. The AP1000 holds a pool of water above the reactor, ready to flood it via gravity. But Markey’s letter suggests that if the AP1000’s containment building is compromised by an earthquake, the passive cooling system could fail.
Southern Company released a statement yesterday saying that its leadership “continues to monitor the recent events in Japan, and remains committed to completing the new Vogtle units on schedule and on budget.” The statement argues that the site’s seismic risk is “much lower” than Japan’s, as is the risk of a tsunami 130 miles from the Atlantic coast and 220 feet above sea level.
The French nuclear engineering firm Areva also defended its EPR design, which is also pending NRC approval. While the EPR relies on active pumping to maintain reactor cooling, an Areva spokesman told Technology Review yesterday that it has extra backup generators for added redundancy. And the diesel tanks to fuel the EPR’s generators would be protected by bunkers, unlike those that were washed away by Friday’s tsunami in Japan.
David Lochbaum, a nuclear engineer and director for nuclear safety at the Union of Concerned Scientists, is critical of the NRC’s policing of safety at existing plants in the U.S. He wants the NRC to take a second look at critical vulnerabilities to power blackouts, including outdated fire-suppression equipment and battery-power backups that, at most U.S. plants, provide for only four hours of reactor cooling—half the capacity of batteries at Japanese plants. “We’re light compared to what Japan had, and Japan came up short,” says Lochbaum.
Just as serious is the U.S. nuclear operators’ heavy reliance on cooling ponds rather than more expensive but safer dry-cask storage of their spent fuel. Lochbaum notes that the spent fuel ponds for 23 U.S. reactors are in the attic of their concrete reactor buildings—structures that were blown away by the first two hydrogen explosions at Fukushima.