govNRC CONCLUDES ITS REVIEW OF FENOC’S ROOT CAUSE ANALYSISOF

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NRC NEWSU.S. NUCLEAR REGULATORY COMMISSIONOffice of Public Affairs Region III2443 Warrenville RoadLisle IL 60532Site: www.nrc.govBlog: http://public-blog.nrc-gateway.govNo. III-12-023Contact: Viktoria Mitlyng (630) 829-9662Prema Chandrathil (630) 829-9663June 21, 2012E-Mail: OPA3@nrc.govNRC CONCLUDES ITS REVIEW OF FENOC’S ROOT CAUSE ANALYSISOF DAVIS-BESSE SHIELD BUILDING CRACKSThe Nuclear Regulatory Commission has completed its review of FirstEnergy Nuclear Operating Co.’s (FENOC) causal analysis of, and proposed corrective actions for, cracks in the shield building at the Davis-Besse Nuclear Power Station. The NRC has determined the reportestablished a sufficient basis for its conclusions. The plant is located in Oak Harbor, Ohio, approximately 21 miles southeast of Toledo.FENOC concluded that cracks in the shield building were caused by environmental factors that resulted from the 1978 blizzard; the lack of moisture protective coating; and certain aspects of the shield building’s design. The company submitted the root cause analysis of shield building cracks, which includes the company’s proposed corrective actions and long-term monitoring program of the shield building, on Feb. 28 in compliance with commitments thecompany made to the NRC.“Our inspectors conducted a thorough and independent review of FENOC’s root cause determination to make sure that the reasons for the internal cracks in the shield building are wellunderstood. We evaluated the effectiveness of the company’s proposed actions to ensure the continued safety of the shield building going forward,” said NRC Region III AdministratorCharles Casto. “We will schedule a public meeting shortly to discuss this issue and the NRC’s plans to monitor the plant’s corrective actions.”The NRC also conducted a detailed analysis of the company’s corrective actions to ensure shield building safety going forward. These actions included additional tests and laboratory analysis of the shield building; applying a protective moisture coating on the building; and plans to restore the plant’s design and licensing basis. These reviews were performed by a team of four NRC inspectors who took a wide rangeof actions to make sure the company’s data and analysis were thorough and rigorous. The NRCteam concluded that the actions proposed by the company going forward would prevent recurrence of the laminar cracking if properly implemented.
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The NRC documented the results of its independent inspection in a document that will bepublically available at: http://adams.nrc.gov/wba/; enter ML12173A023 as a search term. Thereport can also be obtained from the NRC Region III Office of Public Affairs.The NRC began looking at the issue on Oct. 10, 2011, when the NRC was informed byFENOC that its workers identified cracks in the shield building while the plant was shut down to replace the reactor vessel head. The shield building is a 2.5-foot thick reinforced concrete building that surrounds a 1.5-inch thick steel containment vessel that encloses the reactor. Thetwo buildings are separated by a 4.5-foot space.The NRC thoroughly reviewed the cracks after they were discovered and determined that they did not pose an imminent safety issue. The NRC issued an inspection report documentingthe agency’s review of the shield building’s operability on May 7. Before the plant returned to service, the NRC issued a Confirmatory Action Letter to FENOC documenting its commitments to determine the cause of the shield building cracks.The NRC’s license renewal experts are evaluating the implications of this issue in the context of Davis-Besse’s request to extend its operating license.The NRC is developing a program of short-term and long-term inspections to make sureFENOC implements the corrective actions outlined in the root cause analysis in a thorough and timely manner.Documents associated with shield building cracking can be found at:http://www.nrc.gov/info-finder/reactor/davi.html.###News releases are available through a free listserv subscription at the following Web address: http://www.nrc.gov/public-involve/listserver.html. The NRC homepage at www.nrc.gov also offers a SUBSCRIBElink. E-mail notifications are sent to subscribers when news releases are posted to NRC's website.