ML032690956
| ML032690956 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 09/25/2003 |
| From: | Stephen Dembek NRC/NRR/DLPM/LPD4 |
| To: | Overbeck G Arizona Public Service Co |
| Fields M B, NRR/DLPM, 415-3062 | |
| References | |
| TAC MB4498, TAC MB4499, TAC MB4500, TAC MB4645, TAC MB4646, TAC MB4647 | |
| Download: ML032690956 (7) | |
Text
September 25, 2003 Mr. Gregg R. Overbeck Senior Vice President, Nuclear Arizona Public Service Company P. O. Box 52034 Phoenix, AZ 85072-2034
SUBJECT:
PALO VERDE NUCLEAR GENERATING STATION, UNITS 1, 2, AND 3 -
RELIEF REQUEST NOS. 20 AND 21 RE: ALTERNATIVES TO INSERVICE INSPECTION PROGRAM FLAW REPAIR REQUIREMENTS (TAC NOS.
MB4498, MB4499, MB4500, MB4645, MB4646, AND MB4647)
Dear Mr. Overbeck:
By letter dated March 15, 2002, as supplemented by letter dated August 19, 2003, you submitted Relief Request Nos. 20 and 21, requesting relief from requirements in the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (the ASME Code) for the Palo Verde Nuclear Generating Station, Units 1, 2, and 3. In your request, you proposed alternatives to the ASME Code Section XI requirements that preclude welding over or embedding an existing flaw. These requests are based on the use of the Westinghouse repair methodology as documented in WCAP-15987-P, Revision 2, Technical Basis for the Embedded Flaw Process for Repair of Reactor Vessel Head Penetrations, which was reviewed and approved by the staff in a July 3, 2003 Safety Evaluation (ML031840237).
Based on the enclosed Safety Evaluation, the NRC staff concludes that the proposed alternatives provide an acceptable level of quality and safety. Therefore, pursuant to 10 CFR 50.55a(a)(3)(i) of Title 10 of the Code of Federal Regulations, the NRC staff authorizes the proposed alternatives in Relief Request Nos. 20 and 21 to the flaw repair requirements of IWA-4170 and IWA-4310 of ASME Code Section XI at Palo Verde Nuclear Generating Station, Units 1, 2, and 3 for the second 10-year inservice inspection interval.
Sincerely,
/RA/
Stephen Dembek, Chief, Section 2 Project Directorate IV Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket Nos. STN 50-528, STN 50-529, and STN 50-530
Enclosure:
Safety Evaluation cc w/encl: See next page
September 25, 2003 Mr. Gregg R. Overbeck Senior Vice President, Nuclear Arizona Public Service Company P. O. Box 52034 Phoenix, AZ 85072-2034
SUBJECT:
PALO VERDE NUCLEAR GENERATING STATION, UNITS 1, 2, AND 3 -
RELIEF REQUEST NOS. 20 AND 21 RE: ALTERNATIVES TO INSERVICE INSPECTION PROGRAM FLAW REPAIR REQUIREMENTS (TAC NOS.
MB4498, MB4499, MB4500, MB4645, MB4646, AND MB4647)
Dear Mr. Overbeck:
By letter dated March 15, 2002, as supplemented by letter dated August 19, 2003, you submitted Relief Request Nos. 20 and 21, requesting relief from requirements in the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (the ASME Code) for the Palo Verde Nuclear Generating Station, Units 1, 2, and 3. In your request, you proposed alternatives to the ASME Code Section XI requirements that preclude welding over or embedding an existing flaw. These requests are based on the use of the Westinghouse repair methodology as documented in WCAP-15987-P, Revision 2, Technical Basis for the Embedded Flaw Process for Repair of Reactor Vessel Head Penetrations, which was reviewed and approved by the staff in a July 3, 2003 Safety Evaluation (ML031840237).
Based on the enclosed Safety Evaluation, the NRC staff concludes that the proposed alternatives provide an acceptable level of quality and safety. Therefore, pursuant to 10 CFR 50.55a(a)(3)(i) of Title 10 of the Code of Federal Regulations, the NRC staff authorizes the proposed alternatives in Relief Request Nos. 20 and 21 to the flaw repair requirements of IWA-4170 and IWA-4310 of ASME Code Section XI at Palo Verde Nuclear Generating Station, Units 1, 2, and 3 for the second 10-year inservice inspection interval.
Sincerely,
/RA/
Stephen Dembek, Chief, Section 2 Project Directorate IV Division of Licensing Project Management Office of Nuclear Reactor Regulation DISTRIBUTION Docket Nos. STN 50-528, STN 50-529, PUBLIC TChan and STN 50-530 PDIV-2 r/f GCheruvenki RidsNrrDlpmLpdiv (HBerkow) GHill (6)
Enclosure:
Safety Evaluation RidsNrrPMMFields JClark, EDO RidsNrrLAMMcAllister SBloom cc w/encl: See next page RidsAcrsAcnwMailCenter RidsOgcRp RidsRgn4MailCenter (LSmith)
ACCESSION NO: ML032690956 *EMCB Memorandum dated 09/16/03 NRR-028 OFFICE PDIV-2/PM PDIV-1/LA EMCB/SC OGC Nlo PDIV-2/SC NAME MFields:sp MMcAllister TChan Subject to chg SER SDembek JMoore DATE 9/23/03 9/23/03 9//23/03 9/25/03 9/25/03
DOCUMENT NAME: C:\ORPCheckout\FileNET\ML032690956.wpd OFFICIAL RECORD COPY
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION INSERVICE INSPECTION PROGRAM RELIEF REQUEST NOS. 20 AND 21 ARIZONA PUBLIC SERVICE COMPANY, ET AL.
PALO VERDE NUCLEAR GENERATING STATION, UNITS 1, 2, AND 3 DOCKET NOS. STN 50-528, STN 50-529, AND STN 50-530
1.0 INTRODUCTION
The Inservice Inspection (ISI) of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (Code) Class 1, 2, and 3 components is to be performed in accordance with Section XI of the ASME Code and applicable edition and addenda as required by 10 CFR 50.55a(g), except where specific relief has been granted by the Commission pursuant to 10 CFR 50.55a(g)(6)(i). Section 10 CFR 50.55a(a)(3) of Title 10 of the Code of Federal Regulations (10 CFR), states in part that alternatives to the requirements of paragraph (g) may be used, when authorized by the NRC, if the licensee demonstrates that:
(i) the proposed alternatives would provide an acceptable level of quality and safety, or (ii) compliance with the specified requirements would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety.
Pursuant to 10 CFR 50.55a(g)(4), ASME Code Class 1, 2, and 3 components (including supports) will meet the requirements, except the design and access provisions and the preservice examination requirements, set forth in the ASME Code,Section XI, Rules for Inservice Inspection of Nuclear Power Plant Components, to the extent practical within the limitations of design, geometry, and materials of construction of the components. The regulations require that inservice examination of components and system pressure tests conducted during the first 10-year interval and subsequent intervals comply with the requirements in the latest edition and addenda of Section XI of the ASME Code incorporated by reference in 10 CFR 50.55a(b) 12 months prior to the start of the 120-month interval, subject to the limitations and modifications listed therein. The ISI code of record for Palo Verde Nuclear Generating Station (PVNGS), Units 1, 2, and 3 second 10-year ISI interval is the 1992 Edition, 1992 Addenda of Section XI of the ASME Code.
By letter dated March 15, 2002, as supplemented by letter dated August 19, 2003, Arizona Public Service (the licensee), submitted requests for relief for PVNGS, Units 1, 2, and 3.
Specifically, the licensees Relief Request Nos. 20 and 21 proposed alternatives to use an embedded repair technique if cracks were found on the inside and/or outside diameter of the Palo Verde control element drive mechanism (CEDM) nozzles or on the J-groove attachment welds, respectively. These techniques would be used in lieu of the ASME Code Section XI requirements that preclude welding over or embedding an existing flaw.
2.0 INSERVICE INSPECTION PROGRAM RELIEF REQUEST NOS. 20 AND 21
2.1 ASME Code Components Affected
Relief Request Number 20 would allow repairs on the inside diameter of CEDM penetrations.
Relief Request Number 21 would allow repairs on the outside diameter of the CEDM penetrations as well as on the J-groove attachment welds on Vessel Head Penetrations (VHP).
2.2 Code Requirements for which Relief is Requested ASME Section XI, IWA-4170 states in part:
(b) Repairs shall be performed in accordance with the Owners Design Specification and the original Construction Code of the component or system. Later Editions and Addenda of the Construction Code or of Section III, either in their entirety or portions thereof, and Code Cases may be used...
ASME Section XI, IWA-4310, Defect Removal Procedure, states in part:
Defects shall be removed or reduced in size in accordance with Paragraph...
ASME Code,Section XI, sub-articles IWA-4170 and IWA-4310, do not allow welding over or embedding an existing flaw.
2.3 Licensees Proposed Alternative to Code As an alternative to the rules contained in the 1992 ASME Code Section XI, subarticles IWA-4170 and IWA-4310, which do not allow welding over or embedding an existing flaw, the licensee requested the NRC to approve the use of the proposed alternative method outlined in Westinghouse Topical Report WCAP-15987-P Revision 2, Technical Basis for the Embedded Flaw Process for Repair of Reactor Vessel Head Penetrations dated May 16, 2003 (ML031840237). In an August 19, 2003, letter which responded to the staffs request for additional information, the licensee stated it would follow the guidelines outlined in the Westinghouse topical report, including the Conditions and Limitations identified in Section 5.0 of the NRCs July 3, 2003, Safety Evaluation of the WCAP report (see Section 3.0 below for details).
2.4 Licensees Basis for Relief The bases for the alternative requirements [allowing seal weld repairs of circumferential and axial cracks in the VHP nozzle ID (inside diameter) at or above the J-groove weld, in the VHP nozzle ID and OD (outside diameter) below the J-groove weld, and in the J-groove weld]
are discussed in detail in WCAP-15987-P Revision 2.
The staffs July 3, 2003, Safety Evaluation found WCAP-15987-P Revision 2 to be acceptable for referencing in licensing applications as an alternative to the 1989 Edition of Section III of the ASME Code, with limitations noted in Section 3.0 below. Since the ISI Code of Record for the PVNGS units differs from the code edition referenced in the WCAP, the licensee performed a
code reconciliation to verify that the bases contained in this WCAP are applicable to the PVNGS units.
3.0 STAFF EVALUATION The staff has reviewed Westinghouse Topical Report WCAP-15987-P, Revision 2, and in a letter dated July 3, 2003 (ML031840237), the staff accepted the referencing of the topical report for use with the following limitations:
- 1. Licensees must follow the NRC flaw evaluation guidelines provided in the R. J. Barrett (NRC) letter to A. Marion (Nuclear Energy Institute), Flaw Evaluation Guidelines, April 11, 2003. (ML030980322)
- 2. The crack growth rate referenced in WCAP-15987-P, Revision 2 is not applicable to Alloy 600 or Alloy 690 weld material, i.e., Alloy 52, 82, 152, and 182 filler material.
- 3. The nondestructive examination (NDE) requirements listed in the table below must be implemented for examinations of repairs made using the embedded flaw process.
Repair Location Flaw Orientation Repair Repair NDE ISI NDE of the repair, Weld Note 2 VHP Nozzle ID Axial Seal UT and Surface UT or Surface VHP Nozzle ID Circumferential Note 1 Note 1 Note 1 VHP Nozzle OD Axial of Note 1 Note 1 Note 1 above J-groove Circumferential weld VHP Nozzle OD Axial or Seal UT or Surface UT or Surface below J-groove Circumferential weld J-groove weld Axial Seal UT and Surface, UT and Surface, Note 3 Note 3 J-groove weld Circumferential Seal UT and Surface, UT and Surface, Note 3 Note 3 Notes: 1. Repairs must be reviewed and approved separately by the NRC.
- 2. Inspection consistent with the NRC Order EA-03-009 dated February 11, 2003, and any subsequent changes.
- 3. Inspect with personnel and procedures qualified with UT performance-based criteria. Examine the accessible portion of the repaired region. The UT coverage plus surface coverage must equal 100 percent.
The licensee stated that it would use this Westinghouse topical report and would follow the conditions and limitations identified above.
In addition, the licensee performed a code reconciliation between the 1989 Edition ASME Code version referenced in WCAP-15987-P, Revision 2 and ISI Code of Record for the PVNGS units, the 1992 Edition through the 1992 Addenda, to ensure all related requirements would be met.
The licensee concluded that there were no significant differences between the code versions for the applicable code requirements and that the technical findings in WCAP-15987-P, Revision 2 are valid for the PVNGS units. The staff agrees with the licensees conclusions in this matter.
Therefore, the staff finds the use of the reactor vessel head penetration repair methodology as described in WCAP-15987-P, Revision 2, to be acceptable for the PVNGS Units, 1, 2, and 3, for the second 10-year ISI interval.
4.0 CONCLUSION
The NRC staff concludes that the proposed alternatives as stated in Relief Request Nos. 20 and 21 provide an acceptable level of quality and safety. Therefore, pursuant to 10 CFR 50.55a(a)(3)(i), the NRC staff authorizes the proposed alternatives in Relief Request Nos. 20 and 21 to the flaw repair requirements of IWA-4170 and IWA-4310 of ASME Code Section XI at PVNGS, Units 1, 2, and 3 for the second 10-year ISI interval.
All other requirements of the ASME Code,Section III and XI for which relief has not been specifically requested and approved remain applicable, including third party review by the Authorized Nuclear Inservice Inspector.
Principal Contributor: E. Reichelt Date: September 25, 2003
Palo Verde Generating Station, Units 1, 2, and 3 cc:
Mr. Steve Olea Mr. John Taylor Arizona Corporation Commission Public Service Company of New Mexico 1200 W. Washington Street 2401 Aztec NE, MS Z110 Phoenix, AZ 85007 Albuquerque, NM 87107-4224 Douglas Kent Porter Ms. Cheryl Adams Senior Counsel Southern California Edison Company Southern California Edison Company 5000 Pacific Coast Hwy Bldg DIN Law Department, Generation Resources San Clemente, CA 92672 P.O. Box 800 Rosemead, CA 91770 Mr. Robert Henry Salt River Project Senior Resident Inspector 6504 East Thomas Road U.S. Nuclear Regulatory Commission Scottsdale, AZ 85251 P. O. Box 40 Buckeye, AZ 85326 Terry Bassham, Esq.
General Counsel Regional Administrator, Region IV El Paso Electric Company U.S. Nuclear Regulatory Commission 123 W. Mills Harris Tower & Pavillion El Paso, TX 79901 611 Ryan Plaza Drive, Suite 400 Arlington, TX 76011-8064 Mr. John Schumann Los Angeles Department of Water & Power Chairman Southern California Public Power Authority Maricopa County Board of Supervisors P.O. Box 51111, Room 1255-C 301 W. Jefferson, 10th Floor Los Angeles, CA 90051-0100 Phoenix, AZ 85003 Brian Almon Mr. Aubrey V. Godwin, Director Public Utility Commission Arizona Radiation Regulatory Agency William B. Travis Building 4814 South 40 Street P. O. Box 13326 Phoenix, AZ 85040 1701 North Congress Avenue Austin, TX 78701-3326 Mr. Craig K. Seaman, Director Regulatory Affairs/Nuclear Assurance Palo Verde Nuclear Generating Station P.O. Box 52034 Phoenix, AZ 85072-2034 Mr. Hector R. Puente Vice President, Power Generation El Paso Electric Company 2702 N. Third Street, Suite 3040 Phoenix, AZ 85004