DCL-14-072, Unit 2 - Relief Request NDE-SFW-13: Correction to the List of Docket Numbers

Unit 2 - Relief Request NDE-SFW-13: Correction to the List of Docket Numbers

ML14224A658
Person / Time
Site:	Diablo Canyon
Issue date:	08/12/2014
From:	Allen B Pacific Gas & Electric Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
DCL-14-072
Download: ML14224A658 (7)

Text

Pacific Gas and Electric Company Barry S. Allen Diablo Canyon Power Plant Site Vice President Mail Code 104/6 P. 0. Box 56 Avila Beach, CA 93424 August 12, 2014 805.545.4888 Internal: 691.4888 PG&E Letter DCL-14-072 Fax: 805.545.6445 U.S. Nuclear Regulatory Commission 10 CFR 50.55a ATTN: Document Control Desk Washington, DC 20555-0001 Docket No. 50-275, OL-DPR-80 Docket No. 50-323, OL-DPR-82 Diablo Canyon Power Plant Unit 1 and Unit 2 Relief Request NDE-SFW-13: Correction to the List of Docket Numbers

Reference:

1. PG&E Letter DCL-13-121, "ASME Code Section Xllnservice Inspection Program Request for Alternative NDE-SFW-13 to Allow Use of Alternate Examination Requirements," dated December 18, 2013 (ML13353A475)

In Reference 1, Pacific Gas and Electric Company (PG&E) submitted Relief Request NDE-SFW-13 for approval of an alternative to the ASME Code,Section XI, lnservice Inspection (lSI) Program requirements, that was applicable to both Diablo Canyon Power Plant (DCPP) Unit 1 and Unit 2. However, only DCPP Unit 2 docket number was included on the cover letter inadvertently. As a result, the relief request is being resubmitted to include both DCPP Unit 1 and Unit 2 docket numbers. There have been no revisions to the relief request previously submitted in Reference 1. The details of the previously submitted relief request are enclosed.

PG&E requests approval of NDE-SFW-13 by December 23, 2014.

PG&E makes no regulatory commitments (as defined by NEI 99-04) in this letter.

If you have any questions regarding the information enclosed, or other lSI program activities, please contact Mr. Tom Baldwin at (805) 545-4720.

Sincerely,

~7 5. AA--

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

• Comanche Peak

• Diablo Canyon

• Palo Verde

• Wolf Creek

Document Control Desk PG&E Letter DCL-14-072 August 12, 2014 Page 2 rntt/4231 /50639272 and 50033145-84 Enclosure cc: Diablo Distribution cc/enc: Marc L. Dapas, NRC Region IV Administrator Thomas R. Hipschman, NRC Senior Resident Inspector Gonzalo L. Perez, Branch Chief, California Department of Public Health Balwant K. Singal, NRC Project Manager State of California, Pressure Vessel Unit A member of the STARS (Strategic Teaming and Resource Sharing) Alliance Callaway

• Comanche Peak

• Diablo Canyon

• Palo Verde

• Wolf Creek

Enclosure PG&E Letter DCL-14-072 10 CFR 50.55a Request for Alternative NDE-SFW-13 Proposed Alternative in Accordance with 10 CFR 50.55a(a)(3)(i)

Enclosure PG&E Letter DCL-14-072 10 CFR 50.55a Request for Alternative NDE-SFW-13 Proposed Alternative in Accordance with 10 CFR 50.55a(a)(3)(i)

--Alternative Provides Acceptable Level of Quality and Safety--

1. ASME Code Component(s) Affected The American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code,Section XI, Class 1, Diablo Canyon Power Plant (DCPP), Units 1 and 2, reactor vessel shell-to-flange welds:

Code Cat/Item Description Weld Number B-A/81.30 Shell-to-Flange Weld 7-442 (Unit 1)

B-A/81.30 Shell-to-Flange Weld 7-201 (Unit 2)

2. Applicable Code Edition and Addenda The DCPP Units 1 and 2 third interval lnservice Inspection (lSI) Program Plan is based on the ASME Section XI, 2001 Edition with 2003 Addenda. ASME Code Section XI, 2001 Edition without Addenda applies to ultrasonic (UT) examinations performed per ASME Code Section XI, Appendix VIII requirements.

3. Applicable Code Requirements ASME Code Section XI, Table IWB-2500-1, Category 8-A, Item 81.30, requires that reactor vessel shell-to-flange welds be volumetrically examined once during each lSI interval. ASME CODE Section XI, Subsection IWA-2232, requires that the UT examination of reactor pressure vessel (RPV) shell-to-flange welds to be performed per the requirements of ASME Code,Section V, Article 4, as supplemented by Appendix I of Section XI. The examination volume extent is identified in the ASME Code,Section XI, Figure IWB-2500-4, "Shell-To-Flange Weld Joint."

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Enclosure PG&E Letter DCL-14-072

4. Impracticality of Compliance Pursuant to 10 CFR 50.55a(a)(3)(i), an alternative is requested to the requirements of Subsection IWA-2232 since the vendor performing the inspection has qualified their equipment, procedures and personnel per the Performance Demonstration Initiative (POl) implementation of ASME Code,Section XI, Appendix VIII, Supplements 4 and 6, as amended by 10 CFR 50.55a.

ASME Code Section XI, Appendix VIII requirements apply to all DCPP reactor vessel shell welds with the exception of the shell-to-flange weld.

Performing the shell-to-flange weld examination in accordance with the requirements of ASME Code,Section XI, IWA-2232 would require the examination vendor to use a different procedure and process than that used for all other shell welds in the reactor vessel. Reactor vessel examination processes qualified to Appendix VIII have been demonstrated to be effective in detecting and sizing flaws.

Background

Both DCPP Units 1 and 2 reactor vessel shell-to-flange welds have received two previous ISis, with the second examination on each unit performed per the POl implementation of ASME Code,Section XI, Appendix VIII rules (Precedent 2).

No service related flaws have been detected in either weld.

The upper shell course material in both DCPP reactors is A-533 Grade B, Class 1, while the flanges are A-508-64 material. The sections are joined with a narrow groove weld with a fit-up opening of approximately 1.375 inches. A general outline of the weld configuration is shown in Figure 1.

5. Proposed Alternative and Basis for Use Pursuant to 10 CFR ~0.55a(a)(3)(i), PG&E requests authorization to use the alternate requirements of ASME Code Section XI, 2001 Edition with no Addenda, Appendix VIII, Supplements 4 and 6, as amended by 10 CFR 50.55a and implemented by the POl for examination of the shell-to-flange weld when examined from the vessel shell. The Appendix VIII requirements will be implemented in lieu of ASME Code,Section XI, IWA-2232 that requires UT examination of the RPV shell-to-flange weld to be in accordance with ASME Code,Section V, Article 4, as supplemented by Appendix I of Section XI.

The proposed alternate ASME Code Section XI, Appendix VIII requirements were established to improve the effectiveness of UT examinations by means of a rigorous, item specific, performance demonstration. The performance demonstration process verifies the capability of personnel, procedures, and equipment to detect and characterize flaws that could be detrimental to the 2

Enclosure PG&E Letter DCL-14-072 structural integrity of the RPV. Since implementation, this process has shown improved performance as compared to the prescriptive requirements of ASME Code,Section V, Article 4.

As stated in Reference 1, "There is clear evidence that the performance demonstration requirements adopted by Section XI of the ASME Code for Boiler and Pressure Vessels has resulted in a positive impact on the reliability of ultrasonic examinations that are performed on piping and pressure vessels."

Although an ASME Code,Section XI, Appendix VIII qualified exam process is not required for the examination of the reactor vessel shell-to-flange welds, the use of Appendix VIII, Supplements 4 and 6 process for detection and sizing of flaws in this weld has been shown to exceed the performance of the ASME Code Section V, Article 4 prescriptive examination process. Therefore, the use of the proposed alternative will continue to provide an acceptable level of quality and safety, and approval is requested pursuant to 10 CFR 50.55a(a)(3)(i).

6. Duration of Proposed Alternative The proposed alternative will apply through the end of the DCPP third lSI interval for each unit. The Unit 1 third interval began on January 1, 2006, and is nominally scheduled to end on May 6, 2015. The Unit 2 third interval began on July 1, 2006, and is nominally scheduled to end March 12, 2016.

7. Precedents Similar requests have been previously approved:

1. Indian Point Unit 2; NRC letter dated April25. 2011 (ADAMS Accession No. ML11109A016).

2. Diablo Canyon Units 1 and 2; NRC letter dated October 26, 2005 (ADAMS Accession No. ML052660331)

8. References

1. NUREG/CR-7165, PNNL-19014, Revision 2, "The Technical Basis Supporting ASME Code,Section XI, Appendix VIII: Performance Demonstration for Ultrasonic Examination Systems."

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I Upper Shell Course Figure 1 Sketch of DCPP Unit 1 and Unit 2 RPV Flange Weld Configuration 1