DCL-10-166, Response to Telephone Conference Call Held 12/08/2010 Between U.S. Nuclear Regulatory Commission and Pacific Gas & Electric Co. Concerning Responses to Requests for Additional Information Related to License Renewal Application

Response to Telephone Conference Call Held 12/08/2010 Between U.S. Nuclear Regulatory Commission and Pacific Gas & Electric Co. Concerning Responses to Requests for Additional Information Related to License Renewal Application

ML110100430
Person / Time
Site:	Diablo Canyon
Issue date:	01/07/2011
From:	Becker J Pacific Gas & Electric Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
DCL-10-166
Download: ML110100430 (6)

Text

Pacific Gas and Electric Company James R. Becker Diablo Canyon Power Plant Site Vice President Mail Code 104/5/601

p. O. Box 56 Avila Beach, CA 93424 805.545.3462 January 7, 2011 Internal: 691.3462 Fax: 805.545.6445 PG&E Letter DCL-1 0-166 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Docket No. 50-275, OL-DPR-80 Docket No. 50-323, OL-DPR-82 Diablo Canyon Units 1 and 2 Response to Telephone Conference Call Held on December 8, 2010, Between the U.S. Nuclear Regulatory Commission and *Pacific Gas and Electric Company Concerning Responses to Requests for Additional Information Related to the Diablo Canyon Nuclear Power Plant, Units 1 and 2, License Renewal Application

Dear Commissioners and Staff:

By letter dated November 23, 2009, Pacific Gas and Electric Company (PG&E) submitted an application to the U.S. Nuclear Regulatory Commission (NRC) for the renewal of Facility Operating Licenses DPR-80 and DPR-82, for Diablo Canyon Power Plant (DCPP) Units 1 and 2, respectively. The application included the license renewal application (LRA), and Applicant's Environmental Report-Operating License Renewal Stage.

On December 8, 2010, a telephone conference call between the NRC and representatives of PG&E was held to obtain clarification on PG&E's response to a request for additional information (RAI), which was submitted to the NRC in PG&E Letter DCL-1 0-148, dated November 24, 2010, regarding RAI D-RAI B2.1.26-3.

PG&E's su*pplemental information to the RAI response for which the staff requested information is provided in Enclosure 1. PG&E revises its response in PG&E Letter DCL-1 0-148 to perform testing of the in-scope 480V and higher power cables at a frequency of at least every 6 years. See amended LRA Table A4-1, License Renewal Commitments, provided in Enclosure 2. LRA Amendment 33 is included in Enclosure 2.

If you have any questions regarding this response, please contact Mr. Terence L. Grebel, License Renewal Project Manager, at (805) 545-4160.

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

• Comanche Peak

• Diablo Canyon

• Palo Ve rde

• San Onofre

• South Texas Project

• Wolf Creek

Document Control Desk PG&E Letter DCL-1 0-166 January 7, 2011 Page 2 I declare under penalty of perjury that the foregoing is true and correct.

Executed on January 7, 2011.

Site Vice President TLG/5454160 Enclosures cc: Diablo Distribution celene: Elmo E. Collins, NRC Region IV Regional Administrator Nathanial B. Ferrer, NRC Project Manager, License Renewal Kimberly J. Green, NRC Project Manager, License Renewal Michael S. Peck, NRC Senior Resident Inspector Alan B. Wang, NRR Project Manager A member of the STARS (Strategic Teaming and Resource Sharing) Alliance Callaway

• Comanche Peak

• Diablo Canyon

• Palo Verde

• San Onofre

• South Texas Project

• Wolf Creek

Enclosure 1 PG&E Letter DCL-10-166 Page 1 of 2 Pacific Gas and Electric (PG&E) Supplement to Telephone Conference Call Held on December 8, 2010, Concerning Response to Request for Additional Information (RAI) Submitted to the NRC in a Letter Dated November 24, 2010, Regarding RAI D-RAI B2.1.26-3 The Diablo Canyon Power Plant does not have any in-scope circuits whose power supply voltage is in the range from 400V to 480V. All in-scope 480V and higher power circuits routed through underground conduit are included in the pull box inspection program and will be included in the cable testing program. PG&E Letter DCL-10-148, dated November 24, 2010, indicated that insulation testing of in scope 480V and higher cables would be tested at least once every 10 years. In-scope 480V and higher power cables will be tested at a frequency of at least every 6 years with the first test completed prior to entering the period of extended operation. See amended LRA Table A4-1 in Enclosure 2.

The in-scope electrical pull boxes between the intake structure and turbine building are designed with drain conduits that drain to pull boxes at the intake and turbine building. The end pull boxes drain to a building sump or to an in-ground drain sump, which is separate from the pull boxes. The in-ground drain sump has an automatic sump pump and high level alarm, which provides indication of pump failure before the sump backs up into pull boxes. The sump pump and alarm features are tested annually in accordance with the plant maintenance work orders. The remaining in-scope electrical pull boxes are located in doors and are not subject to weather related water intrusion. Some of the indoor pull boxes are also equipped with drain conduits that drain to a building sump.

As indicated in PG&E Letter DCL-10-148, the pull box inspection program has been effective in preventing pull box flooding and cable submergence in all in-scope pull boxes. The pull box sump pump and alarm features are tested annually in accordance with the plant maintenance work orders. Pull box inspections are currently being performed bi-monthly in accordance with plant maintenance work orders. The inspections monitor water accumulation during rainy periods. The inspections can be deferred if no rain has fallen since the last inspection. These inspections have demonstrated that event-driven water accumulation from natural sources has not been occurring. Therefore, event-driven inspections are not required. Recent structural pull box inspections have not identified any visible indication of significant cable or cable support degradation. The pull box inspection frequency is subject to change based on inspection results. However, the program will require that in-scope cable pull boxes will be inspected for water accumulation at least once every year.

LRA Section B2.1.26 indicates that as an enhancement, procedures will be implemented for cable testing and periodic inspections of the pull boxes for in-scope medium voltage cables. PG&E revises this procedural commitment as follows.

Procedures will be implemented for cable testing and periodic inspections of the pull

Enclosure 1 PG&E Letter DCL-10-166 Page 2 of 2 boxes for in-scope 480V and higher power cables. These procedures will also include pull box sump pump box and alarm features testing on an annual basis. See amended LRA Table A4-1 in Enclosure 2.

Appendix A PG&E Letter DCL-10-166 Final Safety Analysis Report Supplement Page 1 of 2 LRA Amendment 33 LRA Section Table A4-1 Appendix A PG&E Letter DCL-10-166 Final Safety Analysis Report Supplement Page 2 of 2 Table A4-1License Renewal Commitments Item # Commitment LRA Implementation Section Schedule 56 Procedures will be implemented for: B2.1.26 Prior to the period of A. Cable testing and periodic water accumulation inspections of extended operation the pull boxes for in-scope 480V and higher power cables.

B. Pull box sump pump box and alarm features testing on an annual basis.

57 In-scope 480V and higher power cables will be tested at a frequency of B2.1.26 Prior to the period of at least every 6 years with the first test completed prior to entering the extended operation period of extended operation.