SONGS Plants Ranked Among Worst in Nation for Reactor Safety Hazards

Southern California Edison's two nuclear power plants are ranked among the most likely in the nation to suffer reactor core damage and possible meltdowns should a breach occur in their pressurized water systems, according to the Union of Concerned Scientists. The heightened risk stems from a design defect?common to the nation's 68 pressurized water reactors?that could clog the emergency cooling system if the reactor vessel or cooling water pipes leaked, a new analysis found. "You're basically running a car without brakes and hoping you don't come across any red lights," said Daniel Hirsch, president of the Los Angeles-based Committee to Bridge the Gap, who believes the Nuclear Regulatory Commission should move expeditiously to resolve the sump defect. "In San Onofre's case you have an unfortunate nexus between the risk and its location," he added. According to Hirsch, a meltdown could kill 130,000 people and cause cancer and genetic effects in 300,000 and 600,000 people, respectively. As regulators and the industry seek to address the hazard, a key concern is whether nuke owners will have to shut down their plants and lose revenue to perform structural changes or whether they will be able to manage the risk with only minor modifications and procedural changes. The question is particularly crucial for the San Onofre plants, which tie for third in the organization of scientists' risk list, ranking with the Point Beach 2 plant in Wisconsin. Pacific Gas & Electric's Diablo Canyon is ranked near the bottom of the group's list. The relatively high risk of a sump jam hazard at the San Onofre plants stems from a number of factors, according to David Lochbaum, nuclear safety engineer for the scientists' group. These include the amount of materials that could be ripped loose during a pipe or vessel rupture, the shape of the containment structure, and its influence on the flow of the water and debris, along with the size of the sump screen. The combination of factors make sump screen clogging at San Onofre more likely in the event of a loss-of-coolant accident than at 60 of 66 other pressurized water plants across the nation, Lochbaum added. "The containment sump issue is a credible one," said Scott Burnell, NRC public affairs officer. Officials at the commission are addressing the defect and expect to issue an outline for solutions in 2005 that plant operators would have to carry out by 2007. "According to NRC's own data, there's about a one in three chance that one of the 68 pressurized water reactors will experience core damage between now and the time that the agency intends to fix the containment sump problem," said Lochbaum, who is also urging the commission to act more quickly. Burnell maintains, however, that more recent data show the risk of such an accident by 2007 is less than one in 100. The problem is the potential for debris created during a leak from the pressurized reactor vessel and pipes to clog the screen on the containment vessel sump. If a reactor loses coolant, such debris would prevent water from being pumped through the reactor core to prevent fuel rod damage. That could lead to a meltdown. The NRC is determining whether the hazard should be addressed through structural changes, which likely will require reactor shutdown. The alternative would be to manage the risk through good housekeeping practices, according to Burnell. This would include steps to minimize the amount of potential debris created in an accident. In Edison's response to the NRC last month, the utility said it would train its operators by November 30 to prevent and deal with sump problems. Edison also proposed procedures to use refueling water storage tanks should a breach occur. "Containment cleanliness is really important," said Ray Golden, Edison spokesperson. "We have a very thorough program to assure performance of the recirculation sumps."

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SONGS Plants Ranked Among Worst in Nation for Reactor Safety Hazards

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