ML071280224

Ninety-Day Response to GL 2007-01, Inaccessible or Underground Power Cable Failures That Disable Accident Mitigation Systems or Cause Plant Transients.

ML071280224
Person / Time
Site:	River Bend
Issue date:	05/03/2007
From:	Roberts J C Entergy Operations
To:	Document Control Desk, NRC/NRR/ADRO
References
GL-07-001, RBF1-07-0070
Download: ML071280224 (3)

Text

Entergy Operations, Inc.River Bend Station 5485 U.S. Highway 61 N___..__ nSt. Francisville, LA 70775 E bew Tel 225 381 4149 n 1Fax 225 635 5068-0 jrober3@entergy.com Jerry C. Roberts Director, Nuclear Safety Assurance May 3, 2007 U. S. Nuclear Regulatory Commission Attn: Document Control Desk 11555 Rockville Pike Rockville, Maryland, 20852

Subject:

Response to Generic Letter 2007-01 River Bend Station -Unit 1 Docket No. 50-458 License Number NPF-47 File Code: G9.5 File No.: RBF1-07-0070 RBG-46692

References:

1. NRC Generic Letter 2007-01, dated February 7, 2007 "Inaccessible or Underground Power Cable Failures that Disable Accident Mitigation Systems or Cause Plant Transients" 2. NEI letter from J. H. Riley to Administrative Points of Contact dated March 16, 2007 "Guidance for Response to GL 2007-01" 3. NRC letter from Michael J. Case, to J. H. Riley dated April 13, 2007,"Response to Nuclear Energy Institute (NEI) Letter Dated March 26, 2007 -Re: Interpretation of Generic Letter (GL) 2007-01, Inaccessible or Underground Power Cable Failures that Disable Accident Mitigation Systems or Cause Plant Transients."

Dear Sir or Madam:

Per Reference 1, the NRC issued Generic Letter (GL) 2007-01 to request facilities to submit the following information to the NRC within 90 days of the date of the Generic Letter: (1) Provide a history of inaccessible or underground power cable failures for all cables that are within the scope of 10CFR50.65 (Maintenance Rule) and for all voltage levels. Indicate the type, manufacturer, date of failure, type of service, voltage class, years of service, and the root causes for the failure.(2) Describe inspection, testing and monitoring programs to detect the degradation of inaccessible or underground power cables that support EDGs, offsite power, ESW, service water, component cooling water, and other systems that are within the scope of 10CFR50.65.

The response to Question 1 is provided in the attachment to this letter. In researching plant records for the requested information, River Bend Station used the NEI and NRC guidance provided in References 2 and 3 to clarify the population of cables of interest.

Electronic searches of the corrective action and maintenance databases were performed.

The data indicate that River Bend Station has experienced one cable failure within the scope of the Generic Letter.With regard to Question 2, River Bend's inspection, testing, and monitoring practices include meggering of cables and connected equipment as needed during corrective maintenance activities.

The station's corrective action program is used to determine root cause and the extent of conditions, where deemed necessary, and would be the mechanism for determining the need for and extent of any increased cable monitoring.

No new commitments are identified in this submittal.

If you have any questions or require additional information, please contact Mr. Danny Williamson at 225-381-4279.The requested information is being provided pursuant the requirements of 10 CFR50.54(f).

I declare under the penalty of perjury that the foregoing information is true and correct.Executed on May 3, 2007 XJerry C. Rob~erts Director, Nuclear Safety Assurance Attachment cc: U. S. Nuclear Regulatory Commission Region IV 611 Ryan Plaza Drive, Suite 400 Arlington, TX 76011 NRC Sr. Resident Inspector P. 0. Box 1050 St. Francisville, LA 70775 Attachment Page 1 of 1 RBF1-01-0070 River Bend Station Response to Generic Letter 2007-01 Date of failure: Time in service: Cable type: Voltage class: Manufacturer:

Type of service: Root cause: May 23, 1989 4 years 750 MCM copper triplex, EP insulation, Hypalon jacket with metal shield 15kv Anaconda Cable 1NPSBNJ320, "C" phase output of 13.8 kv reserve station service transformer "B", installed in ductline, continuously energized No formal root cause analysis was performed.

Since this failure occurred concurrent with a failure of the associated station service transformer, it is suspected that the cable insulation was stressed beyond design limits by the transformer failure.Condition Report 89-0784 documented this event.