SONGS Steam Generator Test Failure Prompts NRC Inspection

Three thinning steam generator tubes in San Onofre unit 3 failed during recent in-situ tests, resulting in further scrutiny from federal regulators.

Southern California Edison tested 129 tubes showing signs of premature wear, according to a company release. The procedure, which subjected them to upwards of three times normal operating pressures, are among a range of tests conducted at the plant since a steam leak Jan. 31.

The same week, inspections during a refueling outage at neighboring unit 2 also found 69 of its steam generator tubes were at least 20 percent worn, and 800 tubes were at least 10 percent worn. Two tubes had a third of their thickness worn away. Under a contract with Mitsubishi Heavy Industries, the plant replaced steam generators in both units in 2009 and 2010 at a cost of $671 million.

The Los Angeles Times reported the Nuclear Regulatory Commission will send an augmented inspection team to investigate the test failure in unit 3. Meanwhile, SCE reported repairs at unit 2, including the plugging of some tubes, are almost complete.

Anonymous comments will be moderated. Join for free and post now!