DCL-15-118, Response to NRC Request for Additional Information Regarding Relief Request FLIG-U1

Response to NRC Request for Additional Information Regarding Relief Request FLIG-U1

ML15285A021
Person / Time
Site:	Diablo Canyon
Issue date:	10/12/2015
From:	Allen B Pacific Gas & Electric Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
DCL-15-118
Download: ML15285A021 (5)

Text

Pacific Gas and Electric Company Barry S. Allen Diablo Canyon Power Plant Vice President, Nuclear Services Mail Code 104/6 P. 0. Box 56 Avila Beach, CA 93424 October 12, 2015 805.545.4888 Internal: 691.4888 Fax: 805.545.6445 PG&E Letter DCL-15-118 U.S. Nuclear Regulatory Commission 10 CFR 50.55a ATTN: Document Control Desk Washington, DC 20555-0001 Docket No. 50-275, OL-DPR-80 Diablo Canyon Power Plant Unit 1 Response to NRC Request for Additional Information Regarding Relief Request FLIG-U1

References:

1. PG&E Letter DCL-15-116, "1 0 CFR 50.55a Request FLIG-U 1, Request for Extension of Third lnservice Inspection Interval for Performing Reactor Vessel Stud Hole Ligament Examination," dated October 7, 2015 (ML15280A505)

2. E-mail from NRC Project Manager, Siva P. Lingam, "Request for Additional Information - Diablo Canyon, Unit 1 - Relief Request No.

FLIG-U1, Third lSI Interval for Performing RPV Stud Hole Ligament Examinations (CAC No. MF6790)," dated October 9, 2015 In Reference 1, Pacific Gas and Electric Company (PG&E) submitted Relief Request FLIG-U1 for Diablo Canyon Power Plant Unit 1 for NRC approval. PG&E requested an extension of the third ten year inservice inspection interval for DCPP Unit 1 by approximately thirteen months beyond the ASME Section XI IWA-2430(d)(1) Code-allowed end of interval one year extension, in order tore-perform reactor vessel stud hole ligament examinations, if required (Reference 1).

The NRC Staff provided a request for additional information (RAI) via email dated October 9, 2015 (Reference 2). The Enclosure to this letter provides PG&E's response to the RAI questions . . PG&E makes no regulatory commitments (as defined by NEI 99 04) in this letter. This letter includes no revisions to existing regulatory commitments. If you have any questions or require additional information, please contact Mr. Hossein Hamzehee at (805) 545-4720.

Sincerely, feo ("

Barry S. Allen A member of the STARS (Strategic Teaming and Resource Sharing) Alliance Callaway

• Diablo Canyon

• Palo Verde

• Wolf Creek

Document Control Desk PG&E Letter DCL-15-118 October 12, 2015 Page 2 rntt/4231/50809336-8 Enclosure cc: Diablo Distribution cc/enc: Marc L. Dapas, NRC Region IV Administrator Thomas R. Hipschman, NRC Senior Resident Inspector Siva P. Lingam, NRR Project Manager Gonzalo L. Perez, Branch Chief, California Department of Public Health State of California, Pressure Vessel Unit A member of the STARS (Strategic Teaming and Resource Sharing) Alliance Callaway

• Diablo Canyon

• Palo Verde

• Wolf Creek

Enclosure PG&E Letter DCL-15-118 PG&E Response to NRC Request for Additional Information Regarding Relief Request FLIG-U1 NRC Question RA/-1:

Please describe how the proposed extension of the third 10-year IS/ interval would affect the inservice inspections that would otherwise occur in the 20th refueling outage. Would the same inspections be carried out as per the original schedule or would these inspections be delayed until the beginning of the fourth 10-year IS/ interval?

PG&E Response:

This request is limited only to the volumetric examination of the ligaments in the reactor vessel (RV) flange. The request, if approved, would allqw Diablo Canyon Power Plant (DCPP) to re-perform the volumetric examination, if necessary, with a methodology that is found acceptable to all parties, during Unit 1 twentieth refueling outage (1 R20). DCPP would credit that one specific 1R20 volumetric examination to the third inservice inspection (lSI) interval. All other inservice inspections would continue on the original schedule, with all other 1R20 examinations credited to the fourth lSI interval; since they would not be affected by this one allowance. PG&E believes the ligament examinations conducted in Unit 1 eighteenth refueling outage fully meet the applicable Code requirements.

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Enclosure PG&E Letter DCL-15-118 NRC Question RAI-2:

Please provide a list of the relief requests for Diablo Canyon Unit 1 that expire at the end of the third 10-year inservice inspection interval?

PG&E Response:

Because the relief request for RV Flange ligaments would only extend the third lSI interval for that one examination, all of the relief requests below will still expire at the originally scheduled end of the third interval, i.e., at the end of the current Unit 1 nineteenth refueling outage. A review of all license submittals for the period 2004 to date was performed. The following 9 relief requests for Unit 1 expire at the end of the third 10-year lSI interval:

1. Request NDE-RCS-SE-LP1 CL for Accessibility of the Subject Weld, Approved 2/24/2012 [ML120530680]

2. Request RI-ISI for Risk Informed lSI Program for Pipe Welds, Approved 1/16/2013 [ML12353A130]

3. Request RVFLNG-INT3 for Pressure Test of Reactor Vessel Flange Leakoff Lines, Approved 9/12/2013 [ML13192A354]

4. Request NDE RCS-SE-1 R18 for Alternative Depth Sizing Criteria for Reactor Safe-End Weld Examinations, Approved 1/3/2014

[ML13350A151]

5. Request NDE SFW-13 for Use of Section XI Appendix VIII for Reactor Vessel Flange-to-Vessel Weld, Approved 9/16/2014 [ML14251A468]

6. Request PRS-3 for Pressure Test of Class 1 Vent, Drain and Test Connections Between 1st and 2nd Isolation Devices, Approved 9/18/2015

[M L 15261 A007]

7. Request to use Mechanical Clamping Device for Socket Weld for Vent Valve off Main Steam System Line 1066, Approved 8/4/2014

[ML14088A001] (after prior verbal authorization). Note: This is a one-outage request that happens to coincide with the end of the third interval, i.e., at the end of the current refueling outage (1 R19).

8. Request NDE-SG-MS-IR for Impracticality of Steam Generator Main Steam Nozzle Inner Radius Examination, Submitted 9/24/2015, pending approval for third interval [ML15267A386]

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Enclosure PG&E Letter DCL-15-118

9. Request NDE-FWNS-U1/U2 for Alternate Examination Coverage for Feedwater Nozzle-to-Shell Welds, Submitted pending approval for third interval [ML15246A244]

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