CPSES-200701065, Response to NRC Generic Letter 2007-01, Inaccessible or Underground Power Cable Failures That Disable Accident Mitigation Systems or Cause Plant Transients.

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

ML071790382
Person / Time
Site:	Comanche Peak
Issue date:	06/21/2007
From:	Blevins M, Madden F TXU Generation Co, LP, TXU Power
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
CPSES-200701065, GL-07-001, TAC MD4314, TAC MD4315, TXX-07013
Download: ML071790382 (6)

Text

,,ATXU Power TXU Peweir Mike Blevins Coamiwrte Ma%Steam Senior Vice President &

Ebet S n*att Cdef Nuclear Officer P-O Box 1002 (EMi)

Glen Rose, iX 76043 Tel: 254 897 52M8 Fax: 254 897 6652 Ref: 10CFR50.54(f) mlke.blevins@Wu-com Ref: GL 2007-01 CPSES-200701065 Log # TXX-07103 June 21, 2007 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk 11555 Rockville Pike Rockville, MD 20852

SUBJECT:

COMANCHE PEAK STEAM ELECTRIC STATION (CPSES)

DOCKET NOS. 50-445 AND 50-446 RESPONSE TO NRC GENERIC LETTER 2007-01, "INACCESSIBLE OR UNDERGROUND POWER CABLE FAILURES THAT DISABLE ACCIDENT MITIGATION SYSTEMS OR CAUSE PLANT TRANSIENTS" (TAC NOS. MD4314 and MD4315)

REF: (1) NRC Generic Letter (GL) 2007-01, "Inaccessible Or Underground Power Cable Failures That Disable Accident Mitigation Systems Or Cause Plant Transients," dated February 7, 2007.

(2) TXX-07058, Letter from M. R. Blevins to the NRC Document Control Desk, dated March 9, 2007, 30 Day response to NRC Generic Letter 2007-01.

(3) NRC Letter Regarding Proposed Alternative Course of Action, dated May 10, 2007.

Dear Sir or Madam:

Pursuant to 10 CFR 50.54(f), the attachment to this letter provides the Comanche Peak Steam Electric Stations (CPSES) response to NRC Generic Letter 2007-01, "Inaccessible or Underground Power Cable Failures that Disable Accident Mitigation Systems or Cause Plant Transients" (Reference 1). The generic letter requests licensees to provide a history of inaccessible or underground power cable failures and A member of the STARS (Strategic Teaming and Resource Sharing) Alliance Callaway

• Comanche Peak

• Diablo Canyon

• Palo Verde ° South Texas Project 9 Wolf Creek A~Lfl

TXX-07103 Page 2 of 3 J to describe inspectidn, testing and monitoring programs to detect the degradation of inaccessible or underground power cables within the scope of 10 CFR 50.65.

Comanche Peak Steam Electric Station (CPSES) provided a response under Required Response - Option 2 (Reference 2).

Reference 2 included following commitment regarding CPSES Units 1 and 2.

Number Description of Commitment 27438 CPSES will provide the information requested by NRC Generic Letter 2007-01, "Inaccessible Or Underground Power Cable Failures That Disable Accident Mitigation Systems Or Cause Plant Transients," by July 27, 2007.

As a result of conversation with the NRC Staff on March 20-21, 2007, TXU Power agreed to revise the response date in commitment 27438 from July 27, 2007, to June 22, 2007. The NRC confirmed the acceptability of the June 22, 2007 response date in a letter dated May 10, 2007 (Reference 3).

TXU Power's response to requested items 1 and 2 is provided in the attachment to this letter and closes commitment 27438.

There are no new commitments made to the NRC by this letter.

A member of the STARS (Strategic Teaming and Resource Sharing) Alliance Callaway

• Comanche Peak

• Diablo Canyon

• Palo Verde - South Texas Project

• Wolf Creek

TXX-07103 Page 3 of 3 Should you have any questions, please contact Mr. Carl B. Corbin at (254) 897-0121.

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

Executed on the 2 Ist of June, 2007.

Sincerely, TXU Generation Company LP By: TXU Generation Management Company LLC Its General Partner Mike Blevins By: / 1 22?~

,fred W. Madden Director, Oversight and Regulatory Affairs CBC Attachment c - B. S. Mallett, Region IV M. C. Thadani, NRR Resident Inspectors, CPSES A member of the STARS (Strategic Teaming and Resource Sharing) Alliance Callaway Comanche Peak 9 Diablo Canyon 9 Palo Verde

• South Texas Project

• Wolf Creek C

Attachment to TXX-07103 Page 1 of3 Response to Requested Information of NRC Generic Letter 2007-01, Inaccessible or Underground Power Cable Failures that Disable Accident Mitigation Systems or Cause Plant Transients Below is the Comanche Peak Steam Electric Station (CPSES) response to the Requested Information of NRC Generic Letter 2007-01, "Inaccessible or Underground Power Cable Failures that Disable Accident Mitigation Systems or Cause Plant Transients." The generic letter's "Requested Information" is shown in bold followed by CPSES's response.

In a letter from James H. Riley (Nuclear Energy Institute [NEI]) to plant administrative contacts, dated March 16, 2007, NEI provided guidance for developing a response to GL 2007-01. The NRC accepted the guidance, with certain modifications, in a letter from Michael J. Case (NRC) to James H. Riley, dated April 13, 2007. The responses provided were developed using the NEI guidance as modified by the NRC letter.

NRC Requested Information Item (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.

CPSES Response to Item (1):

Research into inaccessible or underground power cable failures at CPSES revealed 1 failure(s) in power cables within the scope of 10 CFR 50.65. Table 1 below contains the information requested as well as additional information on failure type, component supported and cable identifier.

NRC Requested Information Item (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).

CPSES Response to Item (2):

The underground ductwork at CPSES is designed to slope towards manholes to avoid accumulation of water in the duct banks. The conduits embedded in concrete floors/walls inside the plant are sealed to prevent intrusion of water inside the conduits. These features eliminate or minimize cable exposure to environments of

Attachment to TXX-07103 Page 2 of 3 concern known to impact cable degradation rates identified in this generic letter.

Additionally all power cables at CPSES are suitable for installation in wet or dry locations in trays, conduits or underground ducts. All CPSES power cables were tested at installation.

CPSES has not implemented a specific testing or monitoring program to detect the degradation of inaccessible or underground power cables. However, during motor rework CPSES may test for motor insulation with the connected power cable.

CPSES periodically performs visual inspection for corrosion and degradation of cable tray supports and a preventive maintenance program for inspection/removal of water from manholes. These actions help to eliminate or minimize conditions known to impact cable degradation rates for cables that are within the scope of 10 CFR 50.65.

Attachment to TXX-07103 Page 3 of 3