United States Nuclear Regulatory Commission - Protecting People and the Environment

Morning Report for November 27, 2006

Headquarters Daily Report

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REGION II

CATAWBA SPECIAL INSPECTION TO REVIEW CORRECTIVE ACTIONS FOR DEGRADED SEALS ON BELOW-GRADE ELECTRICAL PENETRATIONS

Licensee/Facility:

DUKE ENERGY CORP.
Catawba 1, Catawba 2
YORK, South Carolina
Dockets: 05000413, 05000414
[1] W-4-LP, [2] W-4-LP
License No:
Notification:

MR Number: 2-2006-0008
Date: 11/24/2006

Discussion:

There have been two actual flooding events at Catawba within the last six months. The first occurred on May 22, 2006, when water that overflowed from the Unit 2 cooling towers traveled through unsealed electrical conduits, cable trenches, and manholes, and entered the 1A diesel generator room through unsealed, below-grade electrical penetrations. The second event occurred on August 30, 2006, when unsealed below-grade electrical penetrations in the turbine building allowed water from a heavy rainstorm to enter the turbine building and accumulate inside the flood walls surrounding the 4.16kV vital bus power transformers. Following the two events, the licensee initiated corrective actions for degraded penetration seals and entered the issues into the company's corrective action program. During the week of November 6, 2006, Region II inspectors examined susceptible below-grade electrical penetrations and determined that the Standby Shutdown Facility (SSF) was also susceptible to flooding through unsealed doors and degraded electrical penetration seals.

Given the actual flooding of the 1A diesel generator room and the 4.16kV vital bus power transformers, and the potential to flood the SSF, the possibility existed for a loss of equipment needed to mitigate a loss of offsite power due to a common event. The circumstances of these events met the NRC Management Directive 8.3, "NRC Incident Investigation Program" deterministic and risk criteria for increased NRC response.

A Special Inspection team will review the facts surrounding the degraded seals in some areas and the lack of seals in others, determine if there are any generic issues for other nuclear plants, and assess the company's overall response and investigation, including areas of the plant where the lack of watertight seals or degradation might be an issue.
The inspection will begin on November 27, 2006.

Accession Numbers:

Accession No Accession Date
ML063310486 11/27/2006

Contacts:

Name Office Abbrev Phone No E-Mail
MOORMAN, JAMES H R2 (404) 562-4647 JHM2@nrc.gov
Page Last Reviewed/Updated Thursday, March 29, 2012