Press Release-IV-09-035, NRC Conducting Special Inspection at Diablo Canyon Nuclear Plant

Press Release-IV-09-035: NRC Conducting Special Inspection at Diablo Canyon Nuclear Plant

ML093340258
Person / Time
Site:	Diablo Canyon
Issue date:	11/24/2009
From:	Office of Public Affairs Region IV
To:
Category:Press Release
References
Press Release-IV-09-035
Download: ML093340258 (1)

Text

NRC NEWS U.S. NUCLEAR REGULATORY COMMISSION Office of Public Affairs Region IV 612 E. Lamar Blvd., Suite 400 Arlington, TX 76011-4125 Telephone: (817) 860-8128 No. IV-09-035 November 30, 2009

Contact:

Victor Dricks E-Mail: OPA4.Resource@nrc.gov Phone: (817) 860-8128 NRC CONDUCTING SPECIAL INSPECTION AT DIABLO CANYON NUCLEAR PLANT The U.S. Nuclear Regulatory Commission is conducting a special inspection at the Diablo Canyon nuclear plant in order to determine how two switches were misaligned, potentially impairing operators ability to respond in the event of a severe accident.

On October 23, during a maintenance procedure, workers discovered that a set of switches that are intended to allow control room operators to remotely open cooling water valves were misaligned. The valves are part of a system that would collect water from the floor of the containment building for recirculation to cool the reactor during some severe accidents. If the valves could not be opened remotely, operators would be required to manually open them or use a different system to provide cooling water for the reactor.

This problem did not endanger public health or safety because operators would have been able to take compensatory actions in the event of a severe accident, said Region IV Administrator Elmo E. Collins. But we want a better understanding of why this occurred and the potential impact of this problem.

A four-person team of NRC specialists will review the circumstances related to the problem, the licensees root cause evaluation and the effect it had on the availability and reliability of plant safety systems. The team consists of the Diablo Canyon senior resident inspector, two reactor specialists and a senior emergency preparedness inspector from the NRCs Region IV office in Arlington, Texas.

The inspection will begin today and is expected to take several days. The team will issue a report about 45 days after completion of the inspection. The report will be available on the agencys online document library at: http://www.nrc.gov/reading-rm/adams/web-based.html.

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http://www.nrc.gov/public-involve/listserver.html . The NRC homepage at www.nrc.gov also offers a SUBSCRIBE link. E-mail notifications are sent to subscribers when news releases are posted to NRC's Web site.