Southern California Edison, operator of the San Onofre Nuclear Generating Station (SONGS), announced more unusual wear has been discovered on steam-generator tubes in the Unit 2 reactor and that it's consistent with the degradation that has left Unit 3 closed since January. While such wear is typical over the life of steam generators, the discoveries are distressing because the tubes are only two years old.
Edison says the latest finds were in two spots on Unit 2 tubes, and that it's too early to draw any conclusions from the unusual wear. Both reactors remain offline until the cause is discovered and remedies satisfy the Nuclear Regulatory Commission.
Among the questions the power company must answer is why the wear was more extensive in Unit 3, which had been online for a shorter time than Unit 2.
The steam generators were manufactured in Japan by Mitsubishi Heavy Industries.
Because the reactors will be offline heading into the summer, when more power is consumed in Southern California, authorities are scrambling for alternative sources that include bringing the AES plant in Huntington Beach back online.