ML072980799
| ML072980799 | |
| Person / Time | |
|---|---|
| Site: | Vogtle, Farley  |
| Issue date: | 11/07/2007 |
| From: | Cotton K NRC/NRR/ADRO/DORL/LPLII-1 |
| To: | George B Southern Nuclear Operating Co |
| Cotton K R, NRR/DORL, 301-415-1438 | |
| References | |
| ISI-GEN-ALT-07-01, TAC MD6307, TAC MD6308 | |
| Download: ML072980799 (6) | |
Text
November 7, 2007 Mr. Ben George Manager, Nuclear Licensing Southern Nuclear Operating Company, Inc.
Post Office Box 12295 Birmingham, AL 35201
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION REGARDING PRESSURIZER NOZZLE WELD OVERLAY ISI-GEN-ALT-07-01, VERSION 1.0 FOR JOSEPH M.
FARLEY NUCLEAR PLANT, UNIT 2, AND VOGTLE ELECTRIC GENERATING PLANT, UNIT 1 (TAC NOS. MD6307 AND MD6308)
Dear Mr. George:
By letter dated July 24, 2007, Southern Nuclear Operating Company requested Nuclear Regulatory Commission (NRC) approval of proposed alternative ISI-GEN-ALT-07-01, Version 1, to allow the application of full structural weld overlays over the pressurizer nozzle dissimilar metal welds for Joseph M. Farley Nuclear Plant, Unit 2 and Vogtle Electric Generating Plant, Unit 1.
The NRC staffs request for additional information (RAI) is enclosed.
Sincerely,
/RA/
Karen Cotton, Project Manager Plant Licensing Branch II-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-364 and 50-424
Enclosure:
RAI cc w/encl: See next page
November 7, 2007 Mr. Ben George Manager, Nuclear Licensing Southern Nuclear Operating Company, Inc.
Post Office Box 12295 Birmingham, AL 35201
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION REGARDING PRESSURIZER NOZZLE WELD OVERLAY ISI-GEN-ALT-07-01, VERSION 1.0 FOR JOSEPH M.
FARLEY NUCLEAR PLANT, UNIT 2, AND VOGTLE ELECTRIC GENERATING PLANT, UNIT 1 (TAC NOS. MD6307 AND MD6308)
Dear Mr. George:
By letter dated July 24, 2007, Southern Nuclear Operating Company requested Nuclear Regulatory Commission (NRC) approval of proposed alternative ISI-GEN-ALT-07-01, Version 1, to allow the application of full structural weld overlays over the pressurizer nozzle dissimilar metal welds for Joseph M. Farley Nuclear Plant, Unit 2 and Vogtle Electric Generating Plant, Unit 1.
The NRC staffs request for additional information (RAI) is enclosed.
Sincerely,
/RA/
Karen Cotton, Project Manager Plant Licensing Branch II-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-364 and 50-424
Enclosure:
RAI cc w/encl: See next page Distribution:
Public RidsOgcRp LPL2-1 R/F RidsAcrsAcnwMailCenter RidsNrrDorlLpl2-1 (EMarinos)
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Accession Number: ML072980799 OFFICE NRR/LPL2-1/PM NRR/LPL2-1/LA NRR/LPL2-1/BC NAME KCotton:nc CSola EMarinos DATE 11 / 6 /07 10 / 31 /07 11 / 7 /07 OFFICIAL RECORD COPY
Enclosure REQUEST FOR ADDITIONAL INFORMATION PRESSURIZER NOZZLE WELD OVERLAY ISI-GEN-ALT-07-01, VERSION 1.0 JOSEPH M. FARLEY NUCLEAR PLANT, UNIT 2 VOGTLE ELECTRIC GENERATING PLANT, UNIT 1 SOUTHERN NUCLEAR OPERATING COMPANY
- 1. In Enclosure 1 of the July 24, 2007 submittal, section 3(c) on page 12, Southern Nuclear Operating Company (the licensee) stated that the inservice inspection of the weld overlay will be performed in accordance with paragraph Q-4300 of Appendix Q to the 2004 Edition of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code),Section XI with Addenda through 2005. Appendix Q also contains paragraph Q-4310, which provides requirements for additional examinations of the weld overlay. However, Section 3(c) does not reference paragraph Q-4310 explicitly. Clarify whether paragraph Q-4310 of Appendix Q to the 2004 Edition of the ASME Code,Section XI, is required as part of Section 3(c) of ISI-GEN-ALT-07-01, Version 1.
- 2. Per Section 3(c) of ISI-GEN-ALT-07-01, Version 1, Paragraph (c) of Q-4300 of Appendix Q states that: The inservice examination acceptance standards of Table IWB-3514-2 shall be satisfied for the weld overlay. Alternatively, for Class 1, 2, or 3 piping systems, the acceptance criteria of IWB-3600, IWC-3600, or IWD-3600 as applicable, shall be satisfied for the weld overlay (a)
The Nuclear Regulatory Commission (NRC) staffs position on indications or flaws detected in the weld overlay has been that primary water stress corrosion cracking (PWSCC) cannot be accepted by IWX-3600 (X = B, C, and D) and cannot be allowed to remain in service (even if the flaws are acceptable per IWB-3514-2) because the industry operating experience and national laboratories tests have suggested that the growth rate of PWSCC can be aggressive and unpredictable. In addition, the current ASME Code,Section XI does not have the crack growth rate for PWSCC in Alloy 82/182 material. Therefore, the licensee should either revise the above requirement to prohibit its use on PWSCC flaws, or justify the above acceptance criteria with respect to PWSCC flaws.
(b)
The above quoted statements can be interpreted that the acceptance criteria of IWB-3600 may be used in lieu of the acceptance criteria of Table IWB-3514-2. The intent of the ASME Code is that the acceptance criteria of Table WB-3514-2 must be used to evaluate recordable indications prior to the use of the acceptance criteria of IWB-3600. The above statements should be changed to read: The inservice examination acceptance standards of Table IWB-3514-2 shall be satisfied for the weld overlay. If Table IWB-3514-2 cannot be satisfied, for Class 1, 2, or 3 piping systems, the acceptance criteria of IWB-3600, IWC-3600, or IWD-3600 as applicable, shall be satisfied for the weld overlay. Clarify the above statements in Paragraph (c) of Q-4300 of Appendix Q. Discuss the need to revise the above requirement for clarification.
- 3. Per Section 3(c) of ISI-GEN-ALT-07-01, Version 1, one of the requirements of Paragraph (c) of Q-4300 of Appendix Q states that Cracks in the outer 25% [percent] of the pipe base metal shall meet the design analysis requirements of Q-3000.
The licensee stated in the submittal that it does not plan to perform ultrasonic examination (UT) of the dissimilar metal weld prior to installation of the weld overlay at VEGP-1. This means that the structural integrity of the original dissimilar metal butt weld is not known.
After the weld overlay installation, the licensee will perform UT examinations per the proposed alternative. However, the UT examination is only qualified to examine the outer 25 percent of the base metal (dissimilar metal weld) thickness after weld overlay installation.
This means that the structural integrity of the inner 75 percent of the base metal cannot be verified. In this case, the licensee needs to assume a worst-case flaw in the inner 75 percent of the base metal/dissimilar metal weld thickness. The worst-case flaw would have a depth of inner 75 percent through wall of the dissimilar metal weld circumferentially and axially. If a crack is detected in the upper 25 percent of the dissimilar metal weld during inservice inspection of the weld overlay, the initial crack in the crack growth calculation should be modeled with a depth of the detected crack in the 25 percent region plus the depth of the worst-case assumed crack of 75 percent through wall. Section 2(a) of ISI-GEN-ALT-07-01, Version 1, has addressed this issue with the appropriate requirement (i.e., detected flaw depth plus worst-case flaw depth). However, Section 3(c) has not addressed this issue with respect to the inservice inspection. Please justify the adequacy of the above requirement in Section 3(c), or revise Section 3(c) to be consistent with the requirements of Section 2(a).
- 4. In Appendix 2, Figure 1, of Enclosure 1, the licensee presented 3 figures for weld overlay examination volume. However, in Section 3(a)(3) of ISI-GEN-ALT-07-01, Version 1, the licensee only referred to Figure 1a and not to Figures 1b and 1c. Also, Figures 1b and 1c were not discussed in other parts of the proposed alternative. Discuss why figures 1b and 1c are included in Appendix 2 if they are not being discussed in ISI-GEN-ALT-07-01, Version 1.
Joseph M. Farley Nuclear Plant, Unit 2 cc:
Mr. J. Randy Johnson Vice President - Farley Joseph M. Farley Nuclear Plant 7388 North State Highway 95 Columbia, AL 36319 Mr. B. D. McKinney, Licensing Manager Southern Nuclear Operating Company, Inc.
P.O. Box 1295 Birmingham, AL 35201-1295 Mr. M. Stanford Blanton Balch and Bingham Law Firm P.O. Box 306 1710 Sixth Avenue North Birmingham, AL 35201 Mr. J. Gasser Executive Vice President Southern Nuclear Operating Company, Inc.
P.O. Box 1295 Birmingham, AL 35201 State Health Officer Alabama Department of Public Health 434 Monroe St.
Montgomery, AL 36130-1701 Chairman Houston County Commission P.O. Box 6406 Dothan, AL 36302 Resident Inspector U.S. Nuclear Regulatory Commission 7388 N. State Highway 95 Columbia, AL 36319 William D. Oldfield SAER Supervisor Southern Nuclear Operating Company, Inc.
P.O. Box 470 Ashford, AL 36312
Vogtle Electric Generating Plant, Unit 1 cc:
Mr. Tom E. Tynan Vice President - Vogtle Vogtle Electric Generating Plant 7821 River Road Waynesboro, GA 30830 Mr. N. J. Stringfellow Manager, Licensing Southern Nuclear Operating Company, Inc.
P.O. Box 1295 Birmingham, AL 35201-1295 Mr. Jeffrey T. Gasser Executive Vice President Southern Nuclear Operating Company, Inc.
P.O. Box 1295 Birmingham, AL 35201-1295 Mr. Steven M. Jackson Senior Engineer - Power Supply Municipal Electric Authority of Georgia 1470 Riveredge Parkway, NW Atlanta, GA 30328-4684 Mr. Reece McAlister Executive Secretary Georgia Public Service Commission 244 Washington St., SW Atlanta, GA 30334 Mr. Harold Reheis, Director Department of Natural Resources 205 Butler Street, SE, Suite 1252 Atlanta, GA 30334 Attorney General Law Department 132 Judicial Building Atlanta, GA 30334 Mr. Laurence Bergen Oglethorpe Power Corporation 2100 East Exchange Place P.O. Box 1349 Tucker, GA 30085-1349 Arthur H. Domby, Esquire Troutman Sanders Nations Bank Plaza 600 Peachtree Street, NE Suite 5200 Atlanta, GA 30308-2216 Resident Inspector Vogtle Plant 8805 River Road Waynesboro, GA 30830 Office of the County Commissioner Burke County Commission Waynesboro, GA 30830