ML070430572
| ML070430572 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 02/21/2007 |
| From: | Kalyanam N NRC/NRR/ADRO/DORL/LPLIV |
| To: | Rosenblum R Southern California Edison Co |
| Kalyanam N, NRR/DORL/LP4, 415-1480 | |
| References | |
| TAC MD1809, TAC MD1810 | |
| Download: ML070430572 (8) | |
Text
February 21, 2007 Mr. Richard M. Rosenblum Senior Vice President and Chief Nuclear Officer Southern California Edison Company San Onofre Nuclear Generating Station P.O. Box 128 San Clemente, CA 92674-0128
SUBJECT:
SAN ONOFRE NUCLEAR GENERATING STATION, UNITS 2 AND 3 -
CORRECTION LETTER FOR THE ISSUANCE OF RELIEF REQUEST RE:
REQUEST FOR RELIEF ISI-3-23 FOR THE THIRD 10-YEAR INSERVICE INSPECTION INTERVAL TO ALLOW THE USE OF AMERICAN SOCIETY OF MECHANICAL ENGINEERS CODE CASE N-746 (TAC NOS. MD1809 AND MD1810)
Dear Mr. Rosenblum:
By letter dated May 16, 2006, Southern California Edison submitted Relief Request ISI-3-23, pursuant to Title 10 of the Code of Federal Regulations paragraph 50.55a(a)(3)(i), to allow the use of American Society of Mechanical Engineers (ASME) Code Case N-746, Use of 46Fe-24Ni-21Cr-6Mo-Cu-N (UNS N08367) Bolting Material for Class 2 and 3 Components, for the third 10-year inservice inspection (ISI) interval, which began on August 18, 2003, and is scheduled to end on August 17, 2013.
The U.S. Nuclear Regulatory Commission (NRC) staff, by letter dated December 27, 2006, authorized RR ISI-3-23 for the current 10-year ISI interval, or until Code Case N-746 is approved for general use by inclusion in Regulatory Guide 1.84.
R. Rosenblum It was subsequently brought to our attention that the December 27, 2006, letter and the Safety Evaluation (SE) did not reference the construction and the code of record years adequately.
We are enclosing revised pages 1, 3, and 4 of the SE and page 1 of the cover letter. The changes are identified by a vertical bar on the right. Please replace the affected pages in the December 27, 2006, cover letter and SE with these revised pages.
Sincerely,
/RA/
N. Kalyanam, Project Manager Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-361 and 50-362
Enclosure:
Page 1 of the cover letter and Pages 1, 3, and 4 of the Safety Evaluation cc w/encl: See next page
ML070430572 OFFICE NRR/LPL4/PM NRR/LPL4/LA NRR/LPL4/BC NAME NKalyanam LFeizollahi DTerao DATE 2/21/07 2/21/07 2/21/07
Mr. Richard M. Rosenblum Senior Vice President and Chief Nuclear Officer Southern California Edison Company San Onofre Nuclear Generating Station P.O. Box 128 San Clemente, CA 92674-0128
SUBJECT:
SAN ONOFRE NUCLEAR GENERATING STATION, UNITS 2 AND 3 - RE:
REQUEST FOR RELIEF ISI-3-23 FOR THIRD 10-YEAR INSERVICE INSPECTION INTERVAL TO ALLOW THE USE OF AMERICAN SOCIETY OF MECHANICAL ENGINEERS CODE CASE N-746 (TAC NOS. MD1809 AND MD1810)
Dear Mr. Rosenblum:
By letter dated May 16, 2006, Southern California Edison (SCE, the licensee) submitted Relief Request ISI-3-23, pursuant to Title 10 of the Code of Federal Regulations (10 CFR) paragraph 50.55a(a)(3)(i), to allow the use of American Society of Mechanical Engineers (ASME) Code Case N-746, Use of 46Fe-24Ni-21Cr-6Mo-Cu-N (UNS N08367) Bolting Material for Class 2 and 3 Components, for the third 10-year inservice inspection (ISI) interval, which began on August 18, 2003, and is scheduled to end on August 17, 2013.
The licensee proposes to use the Code Case for the replacement of bolting material associated with eight saltwater cooling pumps that supply cooling water from the ocean to the component cooling water-heat exchangers at San Onofre Nuclear Generating Station, Units 2 and 3 (SONGS 2 and 3). Use of Code Case N-746 will allow SCE to use Unified Numbering System N08367 (UNS N08367) bolting material conforming to the requirements of SB-691 on replacement Salt Water Cooling Pumps.
The Nuclear Regulatory Commission (NRC) staff finds the licensees request for relief acceptable. Therefore, the NRC staff authorizes the alternative proposed by SCE, in accordance with 10 CFR 50.55a(a)(3)(i), which states that the proposed alternatives may be used when authorized by the Director of the Office of Nuclear Reactor Regulation if the applicant demonstrates that the proposed alternatives would provide an acceptable level of quality and safety.
Based on the information provided in the licensees submittal, the NRC staff concludes that the licensee has provided an acceptable alternative to the requirements of ASME Code,Section XI, 1995 Edition through 1996 Addenda. The staff concludes that the proposed alternative provides reasonable assurance of quality and safety. Therefore, the proposed alternative is authorized pursuant to 10 CFR 50.55a(a)(3)(i) for SONGS 2 and 3 for the current 10-year ISI interval, or until Code Case N-746 is approved for general use by inclusion in Regulatory Guide (RG) 1.84. After that time, if the licensee wishes to continue to use Code Case N-746, the licensee must follow the conditions, if any, specified in the RG.
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION REQUEST FOR RELIEF NUMBER ISI-3-23 SOUTHERN CALIFORNIA EDISON COMPANY SAN ONOFRE NUCLEAR GENERATING STATION, UNITS 2 AND 3 DOCKET NOS. 50-361 AND 50-362
1.0 INTRODUCTION
By letter dated May 16, 2006 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML061380119), the Southern California Edison Company (SCE, the licensee) requested, pursuant to Title 10 of the Code of Federal Regulations (10 CFR),
paragraph 50.55a(a)(3)(i), that the Nuclear Regulatory Commission (NRC) approve Relief Request ISI-3-23. The relief requested approval of American Society of Mechanical Engineers (ASME) Code Case N-746, Use of 46Fe-24Ni-21Cr-6Mo-Cu-N (Unified Numbering System (UNS) N08367) Bolting Material for Class 2 and 3 Components. Specifically, the licensee proposed to use the Code Case for the replacement of bolting material associated with eight saltwater cooling pumps that supply cooling water from the ocean to the component cooling water-heat exchangers at San Onofre Nuclear Generating Station, Units 2 and 3 (SONGS 2 and 3). The ASME Code of record for replacement of components for SONGS 2 and 3 is the ASME Boiler and Pressure Vessel Code,Section XI, 1995 Edition through the 1996 Addenda.
The ASME Code,Section XI, requires that the replacement pumps meet the construction code (or later) to which the original component was constructed. The existing pumps are ASME Code,Section III, Division 1, Class 3 pumps, constructed from 316L stainless steel material which require periodic overhauls to maintain reliability because of saltwater corrosion. The pumps will be replaced using UNS N08367 material, which is saltwater corrosion-resistant.
UNS N08367 material is included in the ASME Code,Section III, 1998 Edition through 2000 Addenda, as an approved material for pressure boundary parts; however, the material is not listed in the ASME Code as an approved bolting material. To allow the use of UNS N08367 material, the ASME Code approved and published Code Case N-746 which approved UNS N08367 material for bolting applications.
Experience has shown the that use of UNS N08367 bolting material is superior to the existing stainless steel bolting material that is currently used. The UNS N08367 bolting material provides superior corrosion resistance in saltwater service and provides galvanic compatibility with the pump pressure boundary parts.
The replacement of the saltwater pumps is scheduled to take place during the third 10-year inservice inspection (ISI) interval which began on August 18, 2003 and is scheduled to end on August 17, 2013. The ISI code of record for the SONGS 2 and 3, is ASME Code,Section XI, 1995 Edition through 1996 Addenda.
of the same chemical composition as the pressure parts, namely N08367. However, N08367 material is not listed in the bolting table (Table 3, ASME Code,Section II, Part D) specified in ASME Code, Section Ill, ND-2128.
For this application, the use of UNS N08367 bolting material is superior to the existing bolting materials in Table 3, ASME Code,Section II, Part D. The current bolting materials available in the Table 3 do not provide the superior corrosion resistance of UNS N08367 material in saltwater service and galvanic compatibility with the pressure boundary parts.
3.1.5 Proposed Alternative and Basis for Use Pursuant to 10 CFR 50.55a(a)(3)(i), SCE proposes to implement Code Case N-746 and use alternative pressure boundary bolting material (UNS N08367) for use on ASME Code, Section Ill, Division 1, Class 3 saltwater cooling pumps. The pumps fall under 10 CFR 50.55a(e), Quality Group C Components meeting the requirements for Class 3 components in the ASME Boiler and Pressure Vessel Code. Specifically, SCE is requesting approval to use Code Case N-746. This proposed alternative would provide an acceptable level of quality and safety and thus would meet the requirements of 10 CFR 50.55a(a)(3).
The pumps are being replaced with UNS N08367 material because of its superior corrosion resistance for saltwater service. The UNS N08367 material is already approved for use as pressure boundary components in various product forms such as plate (SB-688), forgings (SB-462 and SB-564), welded pipe and tube (SB-675, 804, and 676), seamless pipe and tube (SB-690); and rod, bar, and wire (SB-691).
There is a precedent for application of rod material for use as bolting. A review of Table 3, ASME Code,Section II, Part D, shows three nickel-alloy specifications that cover rods:
Ni-Cr-Fe-Mo, Fe-Ni-Cr-Co (SB-572), Ni-Mo-Cr, Ni-Cr-Mo (SB-574), and Ni-Cr-Fe rods (SB-581), listed as bolting. This precedent supports the approval of Code Case N-746.
3.1.6 Duration of Proposed Alternative SCE requests that the 10 CFR 50.55a(a)(3)(i) relief for the alternative bolting material for the saltwater cooling pumps be granted for SONGS 2 and 3 for the third 10-year interval which began on August 18, 2003, and is scheduled to end on August 17, 2013.
3.1.7 Staff Evaluation The licensee requested approval of ASME Code Case N-746, Use of 46Fe-24Ni-21Cr-6Mo-Cu-N (UNS N08367) Bolting Material for Class 2 and 3 Components. The relief is needed because of planned replacement of eight saltwater cooling pumps at SONGS 2 and 3. ASME Code,Section XI, 1995 Edition through the 1996 Addenda is the ISI Code of record for SONGS 2 and 3.
ASME Code,Section XI, requires that the new pumps meet the construction code to which the original item was constructed. The licensee stated that the existing pumps are ASME Code,Section III, Division 1, Class 3 pumps constructed from 316L stainless steel material, which require periodic overhauls to maintain reliability because of corrosion from saltwater. The existing pumps will be replaced with corrosion-resistant material UNS N08367, which is superior material for seawater service as compared to 316L material currently in service. UNS N08367 is a nickel-molybdenum alloy with excellent resistance to chloride pitting and crevice corrosion.
UNS N08367 retains high ductility and impact strength and has been used for chemical process tanks and pipelines, offshore oil and gas production equipment, and seawater heat exchangers.
UNS N08367 material is included in the ASME Code,Section III, 1998 Edition through 2000 Addenda, as an approved material for pressure boundary parts. However, the material is not listed in the ASME Code as an approved bolting material.
To approve the use of UNS N08367 as bolting material, the ASME Code,Section III, approved and published Code Case N-746. The NRC staff finds Code Case N-746 to be acceptable for use and has included it in the forthcoming revision of Regulatory Guide (RG) 1.84, Design, Fabrication, and Materials Code Case Acceptability, ASME Section III. However, the forthcoming revision of RG 1.84 has not yet been published and, therefore, Code Case N-746 is not yet listed as an approved Code Case in RG 1.84.
Based on the pending approval of Code Case N-746, the staff finds the licensees reasoning in support of its request for relief acceptable and concludes that the use of Code Case N-746 is acceptable.
4.0 CONCLUSION
Based on the information provided in the licensees submittal, the NRC staff concludes that the licensee has provided an acceptable alternative to the requirements of ASME Code,Section XI, 1995 Edition through 1996 Addenda. The staff concludes that the proposed alternative provides reasonable assurance of quality and safety. Therefore, the proposed alternative is authorized pursuant to 10 CFR 50.55a(a)(3)(i) for the SONGS 2 and 3 for the current 10-year ISI interval, or until Code Case N-746 is approved for general use by reference in RG 1.84.
After that time, if the licensee wishes to continue to use Code Case N-746, the licensee must follow the conditions, if any, specified in the RG. All other ASME Code, Sections III and XI, requirements for which relief was not specifically requested and authorized herein by the NRC staff remain applicable, including third-party review by the Authorized Nuclear Inservice Inspector.
Principal Contributor: G. Georgiev Date: December 27, 2006
March 2006 San Onofre Nuclear Generating Station Units 2 and 3 cc:
Mr. Daniel P. Breig Southern California Edison Company San Onofre Nuclear Generating Station P.O. Box 128 San Clemente, CA 92674-0128 Mr. Douglas K. Porter, Esquire Southern California Edison Company 2244 Walnut Grove Avenue Rosemead, CA 91770 Mr. David Spath, Chief Division of Drinking Water and Environmental Management P.O. Box 942732 Sacramento, CA 94234-7320 Chairman, Board of Supervisors County of San Diego 1600 Pacific Highway, Room 335 San Diego, CA 92101 Mark L. Parsons Deputy City Attorney City of Riverside 3900 Main Street Riverside, CA 92522 Mr. Gary L. Nolff Assistant Director - Resources City of Riverside 3900 Main Street Riverside, CA 92522 Regional Administrator, Region IV U.S. Nuclear Regulatory Commission 611 Ryan Plaza Drive, Suite 400 Arlington, TX 76011-8064 Mr. Michael R. Olson San Diego Gas & Electric Company 8315 Century Park Ct. CP21G San Diego, CA 92123-1548 Director, Radiologic Health Branch State Department of Health Services P.O. Box 997414, MS 7610 Sacramento, CA 95899-7414 Resident Inspector/San Onofre NPS c/o U.S. Nuclear Regulatory Commission Post Office Box 4329 San Clemente, CA 92674 Mayor City of San Clemente 100 Avenida Presidio San Clemente, CA 92672 Mr. James T. Reilly Southern California Edison Company San Onofre Nuclear Generating Station P.O. Box 128 San Clemente, CA 92674-0128 Mr. James D. Boyd, Commissioner California Energy Commission 1516 Ninth Street (MS 31)
Sacramento, CA 95814 Mr. Ray Waldo, Vice President Southern California Edison Company San Onofre Nuclear Generating Station P.O. Box 128 San Clemente, CA 92764-0128 Mr. Brian Katz Southern California Edison Company San Onofre Nuclear Generating Station P.O. Box 128 San Clemente, CA 92764-0128 Mr. Steve Hsu Department of Health Services Radiologic Health Branch MS 7610, P.O. Box 997414 Sacramento, CA 95899 Mr. A. Edward Scherer Southern California Edison Company San Onofre Nuclear Generating Station P.O. Box 128 San Clemente, CA 92674-0128