LOS ANGELES, Dec 22 (Reuters) - The U.S. Nuclear Regulatory Commission said on Monday the San Onofre Nuclear Generating Station in Southern California will undergo additional oversight after problems related to an emergency battery backup system.
Southern California Edison (SCE) is the primary owner and is the operator of the two-reactor plant, which is in northern San Diego County. Both reactors will continue to operate. The plant has two reactors, each capable of making about 1,100 megawatts of power. Together, the plant can serve about 1.5 million households.
NRC in a statement Monday said its inspectors 'found that the battery used to supply power to plant safety systems under some accident conditions, was inoperable between 2004 and 2008 because of loose electrical connections caused by inadequate maintenance instructions. The problem was discovered on March 25 during testing, prompting the NRC to conduct a special inspection.'
NRC Region IV Administrator Elmo E. Collins said said that the problem was promptly corrected once the NRC found out about it, but added it is 'troubling because the condition persisted for so long.'
There were redundancies to allow power to keep flowing to essential safety systems, 'but the loss of one emergency battery reduced the plant's safety margins,' the NRC said.
The NRC found that the inspection finding was one of low to moderate safety significance. No one was harmed in relation to the incidents related to the finding.
SCE, a subsidiary of Edison International based in suburban Los Angeles, said in a Monday statement, 'The inspection examined an incident in March 2008 involving a discovery by San Onofre personnel that bolts connecting one of nine Unit 2 emergency batteries to a circuit breaker were not as tight as required. The problem was immediately corrected and reported to the commission.'
The NRC said the inspectors found that Southern California Edison was not performing well enough in its own inspections. Before the NRC special inspection, the company attempted to find deficiencies.
However, the NRC said, 'your evaluations lacked the rigor necessary to identify these performance deficiencies' and that SCE's 'ability to effectively evaluate problems has been, and continues to be, a concern to the NRC.'
The NRC said it 'plans to continue to focus inspections in this area until sustained improvements are recognized.'
San Onofre is owned by SCE (78.21 percent), San Diego Gas & Electric, a subsidiary of Sempra Energy (20 percent) and the city of Riverside, California (1.79 percent).
(Reporting by Bernie Woodall; Editing by Christian Wiessner)
((bernie.woodall@thomsonreuters.com; +1 213-955-6752)) Keywords: EDISONINTERNATIONAL NUCLEAR/NRC (For help: Click 'Contact Us' in your desk top, click here or call 1-800-738-8377 for Reuters Products and 1-888-463-3383 for Thomson products; For client training: training.americas@thomsonreuters.com; +1 646-223-5546) COPYRIGHT Copyright Thomson Reuters 2008. All rights reserved. The copying, republication or redistribution of Reuters News Content, including by framing or similar means, is expressly prohibited without the prior written consent of Thomson Reuters.
Southern California Edison (SCE) is the primary owner and is the operator of the two-reactor plant, which is in northern San Diego County. Both reactors will continue to operate. The plant has two reactors, each capable of making about 1,100 megawatts of power. Together, the plant can serve about 1.5 million households.
NRC in a statement Monday said its inspectors 'found that the battery used to supply power to plant safety systems under some accident conditions, was inoperable between 2004 and 2008 because of loose electrical connections caused by inadequate maintenance instructions. The problem was discovered on March 25 during testing, prompting the NRC to conduct a special inspection.'
NRC Region IV Administrator Elmo E. Collins said said that the problem was promptly corrected once the NRC found out about it, but added it is 'troubling because the condition persisted for so long.'
There were redundancies to allow power to keep flowing to essential safety systems, 'but the loss of one emergency battery reduced the plant's safety margins,' the NRC said.
The NRC found that the inspection finding was one of low to moderate safety significance. No one was harmed in relation to the incidents related to the finding.
SCE, a subsidiary of Edison International based in suburban Los Angeles, said in a Monday statement, 'The inspection examined an incident in March 2008 involving a discovery by San Onofre personnel that bolts connecting one of nine Unit 2 emergency batteries to a circuit breaker were not as tight as required. The problem was immediately corrected and reported to the commission.'
The NRC said the inspectors found that Southern California Edison was not performing well enough in its own inspections. Before the NRC special inspection, the company attempted to find deficiencies.
However, the NRC said, 'your evaluations lacked the rigor necessary to identify these performance deficiencies' and that SCE's 'ability to effectively evaluate problems has been, and continues to be, a concern to the NRC.'
The NRC said it 'plans to continue to focus inspections in this area until sustained improvements are recognized.'
San Onofre is owned by SCE (78.21 percent), San Diego Gas & Electric, a subsidiary of Sempra Energy (20 percent) and the city of Riverside, California (1.79 percent).
(Reporting by Bernie Woodall; Editing by Christian Wiessner)
((bernie.woodall@thomsonreuters.com; +1 213-955-6752)) Keywords: EDISONINTERNATIONAL NUCLEAR/NRC (For help: Click 'Contact Us' in your desk top, click here or call 1-800-738-8377 for Reuters Products and 1-888-463-3383 for Thomson products; For client training: training.americas@thomsonreuters.com; +1 646-223-5546) COPYRIGHT Copyright Thomson Reuters 2008. All rights reserved. The copying, republication or redistribution of Reuters News Content, including by framing or similar means, is expressly prohibited without the prior written consent of Thomson Reuters.