K. Mennem 7:17 p.m., June 17
After decades of debate along the west coast, concerns regarding the safety and reliability of nuclear power in the face of an earthquake have gained national prominence.
Last week’s quake in Mineral, Virginia was measured at 5.8 on the Richter scale. Ten miles away at the North Anna Nuclear Generating Station, both of the plant’s generators automatically shut down. The facility, designed to withstand a 6.2 caliber quake, took 1.79 gigawatts of production offline when it closed. Dominion Virginia Power, the plant’s owner, says that’s enough juice to power 450,000 homes.
A Nuclear Regulatory Commission survey in 2010 estimated the odds of a quake strong enough to cause core damage at North Anna in any given year at 1 in 22,737. By contrast, the likelihood of similar disaster befalling California’s nuclear facilities was ranked at 1 in 23,810 for the central coast’s Diablo Canyon, and 1 in 58,824 for the local San Onofre Nuclear Generating Station.
Further, with no outside power coming into the site, four backup diesel generators were required to keep cooling water circulating around the reactors to prevent a possible meltdown. One of the generators failed, and a fifth was brought in. In a letter to Nuclear Regulatory Commission Chairman Greg Jaczko urging stronger maintenance requirements for the backup generators, Assemblyman Edward J. Markey documents 74 such generator failures during plant shutdowns over the last eight years. Similar failures of backup power equipment were responsible for the meltdown at Fukushima in March.
“The Fukushima meltdown was a long-distance warning to the U.S. nuclear industry to bolster its safety systems, including backup power reliability and redundancy,” the Massachusetts Democrat wrote. “The Virginia earthquake is now our local 911 call to stop delaying the implementation of stricter safety standards.”
Other concerns regarding the storage of spent fuel in the east parallel those closer to home at California’s San Onofre and Diablo Canyon nuclear facilities. Without an operational storage site anywhere in the country, spent fuel is often stored in overcrowded water pools that require constant circulation to keep the fuel cool and stable. An alternative method involves sealing fuel in large, sealed concrete storage casks, which require no power and have no moving parts, making them less susceptible to failure or terrorist attack. Much of the United States’ 65,000 metric tons of spent nuclear fuel, however, remains in water pools.