A Bathtub Curve for Nuclear Accidents, compliments of David Lochbaum, Union of Concerned Scientists. "Bathtub" refers to the curve's shape.Friends of the Earth's expert witness, Arnie Gundersen of Fairewinds Associates, addressed a U.S. Nuclear Regulatory Commission (NRC) Petition Review Board yesterday, regarding the premature, severe degradation of Replacement Steam Generator tubes at San Onofre nuclear power plant a year ago. The damage resulted in a tube failure and radioactive steam release, as well as the year-long and counting shutdown of San Onofre Units 2 and 3.
Arnie's slide presentation can be viewed online. He concluded that "San Onofre was a 'near miss.' The tube failures at San Onofre are the worst nuclear equipment failures since the near miss at Davis-Besse in 2002." (slide #36). He quoted NRC's own Augmented Inspection Team report: "Although in this case the degraded condition of the tubes was manifested as a small primary to secondary leak, it is possible that a full blown rupture could have been the first indication."
While the Feb. 2000 Indian Point old steam generator tube rupture, and the Feb./March 2002 Davis-Besse lid corrosion hole, were "break-down phase" accidents, San Onofre 2 & 3's Jan. 2012 steam generator tube degradation is actually a "break-in phase" accident. The replacement steam generators were only a year or two old (see the Bath Tub Curve for Nuclear Accidents, above left). More.