BVY 07-028, Response to Generic Letter 2007-01, Inaccessible or Underground Power Cable Failures That Disable Accident Mitigation Systems or Cause Plant Transients.

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

ML071290055
Person / Time
Site:	Vermont Yankee
Issue date:	04/30/2007
From:	Ted Sullivan Entergy Nuclear Operations, Vermont Yankee
To:	Document Control Desk, NRC/NRR/ADRO
References
BVY 07-028, GL-07-001
Download: ML071290055 (4)

Text

Entergy Nuclear Operations, Inc SEn tergy Vermont Yankee P.O. Box 0500 185 Old Ferry Road Brattleboro, VT 05302-0500 Tel 802 257 5271 April 30, 2007 BVY 07-028 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001

References:

1. NRC Generic Letter 2007-01, "Inaccessible or Underground Power Cable Failures that Disable Accident Mitigation Systems or Cause Plant Transients,"

NVY 07-013, dated February 7, 2007

2. NEI letter from J. H. Riley to Administrative Points of Contact, "Guidance for Response to GL 2007-01, Inaccessible or Underground Power Cable Failures that Disable Accident Mitigation Systems or Cause Plant Transients," dated March 16, 2007

3. NEI letter from J. H. Riley to USNRC "Interpretation of GL 2007-01, Inaccessible or Underground Power Cable Failures that Disable Accident Mitigation Systems or Cause Plant Transients," dated March 26, 2007

4. NRC letter to J. H. Riley, "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," dated April 13, 2007

Subject:

Vermont Yankee Nuclear Power Station License No. DPR-28 (Docket No. 50-271)

Vermont Yankee Response to Generic Letter 2007-01

Dear Sir or Madam:

The NRC issued Generic Letter (GL) 2007-01 (Reference 1) 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 10 CFR 50.65 (the 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 10 CFR 50.65 (the Maintenance Rule).

The response to Question 1 is provided in Attachment 1 to this letter. In researching plant records for the requested information, Vermont Yankee (VY) used the NEI and NRC guidance provided in References 2, 3 and 4 to clarify the population of cables of interest. Data bases researched included reviewing the corrective action program history documented in the Plant

BVY 07-028 / Page 2 of 2 Condition Reporting System (PCRS), the Maintenance Rule data base, the INPO website for VY Licensee Event Reports or VY Operating Experience documents and other historical document searches in the plant records archive database. As a result of this search, VY identified two cable failures within the scope of the GL.

In response to Question 2, VY inspection, testing and monitoring practices presently include visual cable inspections during routine operations and maintenance activities, periodic insulation resistance breakdown megger testing of cables and connected equipment associated with maintenance activities and periodic inspection of manhole conduit water seals. The PCRS is used to determine root cause(s) and extent of condition where deemed necessary and would be the mechanism for determining the need for and extent of any increased cable monitoring.

No new commitments are being made in this submittal.

If you have any questions or require additional information, please contact Mr. David Mannai at 802-258-5422.

The requested information is being provided pursuant the requirements of 10 CFR 50.54(f).

I declare under the penalty of perjury that the foregoing information is true and correct.

Executed on April 30, 2007.

Sincerely,

,tedA ain Site Vice President Vermont Yankee Nuclear Power Station - Vermont Yankee Nuclear Power Station - Cable Failures cc: Mr. Samuel J. Collins, Regional Administrator U.S. Nuclear Regulatory Commission, Region 1 475 Allendale Road King of Prussia, PA 19406-1415 Mr. James S. Kim, Project Manager U.S. Nuclear Regulatory Commission Mail Stop 08C2A Washington, DC 20555 David Pelton, USNRC Resident Inspector Entergy Nuclear Vermont Yankee, LLC P.O. Box 157 Vernon, Vermont 05354 Mr. David O'Brien, Commissioner VT Department of Public Service 112 State Street - Drawer 20 Montpelier, Vermont 05620-2601

BVY 07-028 Docket No. 50-271 Attachment 1 Vermont Yankee Nuclear Power Station Cable Failures

BVY 07-028 / Attachment 1 page 1 of 1 Inaccessible or Underqround Power Cable Failures within the Scope of 10CFR 50.65 for Vermont Yankee Cable Type Voltage Manufacturer Date of Type of Service Root Cause Class Failure /

Service (Yrs.)

3-1/C-350 MCM 37 strand coated 5KV Collyer Insulated 02/05/2006 Cable C1339A, 4160 volt feed to non- Failure appeared to be a copper conductor semi-conducting Wire Company safety Bus 11, Installed in duct bank manufacturing flaw.

tape .172" butyl rubber insulation, 34 years energized 100% of time except for However, despite low semi-conducting bedding tape, 5 specific 5 yr outages megger readings the mil tinned copper shielding tape, cable was able to keep Mylar tape over shield, .080" black load energized. Cable neoprene jacket overall was replaced.

3-1/C-750 MCM ORNS 61 strand 5KV Collyer Insulated 12/02/1997 Cable C1322A-J, 4160 volt feed from Failure appeared to be coated copper conductor semi- Wire Company start-up transformer to non-safety Bus due to installation conducting tape .172" butyl rubber 25 years 1&2, Installed in duct bank energized damage. Cable insulation, semi-conducting bedding 100% of time but is not loaded except continued to supply tape, 5 mil tinned copper shielding during plant outages. power to load. Cable tape, Mylar tape over shield, .080" was replaced.

black neoprene jacket overall