ML061710364

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Monticello Nuclear Generating Plant, Palisades Nuclear Plant, Point Beach Nuclear Plant Units 1 and 2, Prairie Island Nuclear Generating Plant, Units 1 and 2 - Use of ASME Code Case N-513-2
ML061710364
Person / Time
Site: Monticello, Palisades, Point Beach, Prairie Island, Duane Arnold  Entergy icon.png
Issue date: 07/03/2006
From: Raghavan L
Plant Licensing Branch III-2
To: Vanmiddlesworth G, Weinkam E
Duane Arnold, Nuclear Management Co
L. Mark Padovan, LPL3-1
References
TAC MC9478, TAC MC9479, TAC MC9480, TAC MC9481, TAC MC9482, TAC MC9483, TAC MC9484
Download: ML061710364 (16)
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Text

July 3, 2006 Mr. Edward J. Weinkam, Director Nuclear Licensing & Regulatory Services Nuclear Management Company, LLC.

700 First Street Hudson, WI 54016 Mr. Gary Van Middlesworth Vice President Duane Arnold Energy Center FPL Energy Duane Arnold, LLC.

3277 DAEC Road Palo, IA 52324-9785

SUBJECT:

DUANE ARNOLD ENERGY CENTER, MONTICELLO NUCLEAR GENERATING PLANT, PALISADES NUCLEAR PLANT, POINT BEACH NUCLEAR PLANT, UNITS 1 AND 2, PRAIRIE ISLAND NUCLEAR GENERATING PLANT, UNITS 1 AND 2 USE OF ASME CODE CASE N-513-2 (TAC NOS. MC9478 THROUGH MC9484)

Dear Sirs:

Nuclear Management Company, LLCs (NMCs) letter of December 12, 2005, requested we approve a relief request to use the alternative requirements of Code Case N-513-2, "Evaluation Criteria for Temporary Acceptance of Flaws in Moderate Energy Class 2 or 3 Piping," in lieu of Subarticle IWA-4000 of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code,Section XI. This relief request applied to the following nuclear units:

  • Duane Arnold Energy Center
  • Monticello Nuclear Generating Plant
  • Palisades Nuclear Plant
  • Point Beach Nuclear Plant, Units 1 and 2
  • Prairie Island Nuclear Generating Plant, Units 1 and 2 On January 27, 2006, the NRC issued Amendment No. 260 transferring the license for Duane Arnold Energy Center to FPL Energy Duane Arnold, LLC. Accordingly, we are addressing our authorization to both NMC and FPL Energy Duane Arnold, LLC.

Based on our review of the submitted information, we conclude that the proposed alternatives in ASME,Section XI, Code Case N-513-2, as discussed in the request for relief, will provide an acceptable level of quality and safety. Code Case N-513-2 contains requirements to maintain piping structural integrity, and incorporates the conditions listed in Regulatory Guide (RG) 1.147, Inservice Inspection Code Case Acceptability, Revision 14.

Mr. E. J. Weinkam Pursuant to 10 CFR 50.55a(a)(3)(i), the proposed alternative is authorized to perform piping evaluations to determine whether temporary continued operation of applicable ASME Class 2 and 3 piping system is allowed. This authorization applies to Duane Arnold, Monticello, Prairie Island, Units 1 and 2, Point Beach, Units 1 and 2, and Palisades, for the remainder of the 10-year inservice inspection interval of the respective units as noted in the relief request.

Use of the Code Case is authorized until such time as the Code case is published in a future version of RG 1.147, and incorporated by reference in 10 CFR 50.55a(b). At that time, if NMC or FPL Energy Duane Arnold, LLC intends to continue implementing this Code case, it must follow all provisions of Code Case N-513-2 with conditions as specified in RG 1.147, and limitations as specified in Sections 50.55a(b)(4), (b)(5), and (b)(6), if any. If you have any questions, please contact L. Mark Padovan at 301-415-1423.

Sincerely,

/RA/

L. Raghavan, Chief Plant Licensing Branch III-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-331, 50-263, 50-255, 50-266, 50-301, 50-282 and 50-306

Enclosure:

Safety Evaluation ccs w/encl: See next page

ML061710364 OFFICE NRR/LPL3-1/PM NRR/LPL3-1/LA DCI/CFEB/BC OGC NRR/LPL3-1/BC NAME LPadovan THarris KGruss MLemoncelli LRaghavan DATE 6/30/06 6/20/06 5/31/06 6/29/06 7/3/06

Duane Arnold Energy Center cc:

Mr. J. A. Stall Regional Administrator, Region III Senior Vice President, Nuclear and Chief U.S. Nuclear Regulatory Commission Nuclear Officer Suite 210 Florida Power & Light Company 2443 Warrenville Road P. O. Box 14000 Lisle, IL 60532-4351 Juno Beach, FL 33408-0420 Mr. M. S. Ross Mr. M. Warner Managing Attorney Vice President, Nuclear Operations Florida Power & Light Company Support P. O. Box 14000 Florida Power & Light Company Juno Beach, FL 33408-0420 P. O. Box 14000 Juno Beach, FL 33408-0420 Mr. R. E. Helfrich Senior Attorney Mr. D. A. Curtland Florida Power & Light Company Plant Manager P. O. Box 14000 Duane Arnold Energy Center Juno Beach, FL 33408-0420 3277 DAEC Rd.

Palo, IA 52324-9785 Mr. W. E. Webster Vice President, Nuclear Operations Mr. R. S. Kundalkar Florida Power & Light Company Vice President, Nuclear Engineering P. O. Box 14000 Florida Power & Light Company Juno Beach, FL 33408-0420 P. O. Box 14000 Juno Beach, FL 33408-0420 John Bjorseth Site Director Daniel McGhee Duane Arnold Energy Center Utilities Division 3277 DAEC Road Iowa Department of Commerce Palo, IA 52324 Lucas Office Buildings, 5th Floor Des Moines, IA 50319 Steven R. Catron Manager, Regulatory Affairs Chairman, Linn County Duane Arnold Energy Center Board of Supervisors 3277 DAEC Road 930 1st Street SW Palo, IA 52324 Cedar Rapids, IA 52404 U. S. Nuclear Regulatory Commission Mr. Gary Van Middlesworth Resident Inspectors Office Vice President Rural Route #1 Duane Arnold Energy Center Palo, IA 52324 3277 DAEC Road Palo, IA 52324-9785

Monticello Nuclear Generating Plant cc:

Jonathan Rogoff, Esquire Douglas M. Gruber, Auditor/Treasurer Vice President, Counsel & Secretary Wright County Government Center Nuclear Management Company, LLC 10 NW Second Street 700 First Street Buffalo, MN 55313 Hudson, WI 54016 Commissioner U.S. Nuclear Regulatory Commission Minnesota Department of Commerce Resident Inspector's Office 85 7th Place East, Suite 500 2807 W. County Road 75 St. Paul, MN 55101-2198 Monticello, MN 55362 Manager - Environmental Protection Division Manager, Nuclear Safety Assessment Minnesota Attorney Generals Office Monticello Nuclear Generating Plant 445 Minnesota St., Suite 900 Nuclear Management Company, LLC St. Paul, MN 55101-2127 2807 West County Road 75 Monticello, MN 55362-9637 Michael B. Sellman President and Chief Executive Officer Robert Nelson, President Nuclear Management Company, LLC Minnesota Environmental Control 700 First Street Citizens Association (MECCA) Hudson, MI 54016 1051 South McKnight Road St. Paul, MN 55119 Nuclear Asset Manager Xcel Energy, Inc.

Commissioner 414 Nicollet Mall, R.S. 8 Minnesota Pollution Control Agency Minneapolis, MN 55401 520 Lafayette Road St. Paul, MN 55155-4194 Mr. John T. Conway Site Vice President Regional Administrator, Region III Monticello Nuclear Generating Plant U.S. Nuclear Regulatory Commission Nuclear Management Company, LLC Suite 210 2807 West County Road 75 2443 Warrenville Road Monticello, MN 55362-9637 Lisle, IL 60532-4351 Commissioner Minnesota Department of Health 717 Delaware Street, S. E.

Minneapolis, MN 55440

Palisades Plant cc:

Robert A. Fenech, Senior Vice President Michael B. Sellman Nuclear, Fossil, and Hydro Operations President and Chief Executive Officer Consumers Energy Company Nuclear Management Company, LLC 1945 Parnall Rd. 700 First Street Jackson, MI 49201 Hudson, MI 54016 Arunas T. Udrys, Esquire Jonathan Rogoff, Esquire Consumers Energy Company Vice President, Counsel & Secretary 1 Energy Plaza Nuclear Management Company, LLC Jackson, MI 49201 700 First Street Hudson, WI 54016 Regional Administrator, Region III U.S. Nuclear Regulatory Commission Douglas E. Cooper Suite 210 Senior Vice President - Group Operations 2443 Warrenville Road Palisades Nuclear Plant Lisle, IL 60532-4351 Nuclear Management Company, LLC 27780 Blue Star Memorial Highway Supervisor Covert, MI 49043 Covert Township P. O. Box 35 Stephen T. Wawro, Director Covert, MI 49043 of Nuclear Assets Consumers Energy Company Office of the Governor Palisades Nuclear Plant P. O. Box 30013 27780 Blue Star Memorial Highway Lansing, MI 48909 Covert, MI 49043 U.S. Nuclear Regulatory Commission Laurie A. Lahti, Manager Resident Inspector's Office Regulatory Affairs Palisades Plant Nuclear Management Company, LLC 27782 Blue Star Memorial Highway Palisades Nuclear Plant Covert, MI 49043 27780 Blue Star Memorial Highway Covert, MI 49043 Michigan Department of Environmental Quality Waste and Hazardous Materials Division Paul A. Harden Hazardous Waste and Radiological Site Vice President Protection Section Palisades Nuclear Plant Nuclear Facilities Unit Nuclear Management Company, LLC Constitution Hall, Lower-Level North 27780 Blue Star Memorial Highway 525 West Allegan Street Covert, MI 49043 P.O. Box 30241 Lansing, MI 48909-7741 Michigan Department of Attorney General Special Litigation Division 525 West Ottawa St.

Sixth Floor, G. Mennen Williams Building Lansing, MI 48913

Point Beach Nuclear Plant, Units 1 and 2 cc:

Jonathan Rogoff, Esquire Mr. Jeffery Kitsembel Vice President, Counsel & Secretary Electric Division Nuclear Management Company, LLC Public Service Commission of Wisconsin 700 First Street P.O. Box 7854 Hudson, WI 54016 Madison, WI 53707-7854 Mr. F. D. Kuester Nuclear Asset Manager President & Chief Executive Officer Wisconsin Electric Power Company WE Generation 231 West Michigan Street 231 West Michigan Street Milwaukee, WI 53201 Milwaukee, WI 53201 Michael B. Sellman Regulatory Affairs Manager President and Chief Executive Officer Point Beach Nuclear Plant Nuclear Management Company, LLC Nuclear Management Company, LLC 700 First Street 6610 Nuclear Road Hudson, MI 54016 Two Rivers, WI 54241 Douglas E. Cooper Mr. Ken Duveneck Senior Vice President - Group Operations Town Chairman Palisades Nuclear Plant Town of Two Creeks Nuclear Management Company, LLC 13017 State Highway 42 27780 Blue Star Memorial Highway Mishicot, WI 54228 Covert, MI 49043 Chairman Site Director of Operations Public Service Commission Nuclear Management Company, LLC of Wisconsin 6610 Nuclear Road P.O. Box 7854 Two Rivers, WI 54241 Madison, WI 53707-7854 Dennis L. Koehl Regional Administrator, Region III Site Vice-President U.S. Nuclear Regulatory Commission Point Beach Nuclear Plant Suite 210 Nuclear Management Company, LLC 2443 Warrenville Road 6610 Nuclear Road Lisle, IL 60532-4351 Two Rivers, WI 54241 Resident Inspector's Office U.S. Nuclear Regulatory Commission 6612 Nuclear Road Two Rivers, WI 54241

Prairie Island Nuclear Generating Plant, Units 1 and 2 cc:

Jonathan Rogoff, Esquire Tribal Council Vice President, Counsel & Secretary Prairie Island Indian Community Nuclear Management Company, LLC ATTN: Environmental Department 700 First Street 5636 Sturgeon Lake Road Hudson, WI 54016 Welch, MN 55089 Manager, Regulatory Affairs Nuclear Asset Manager Prairie Island Nuclear Generating Plant Xcel Energy, Inc.

Nuclear Management Company, LLC 414 Nicollet Mall, R.S. 8 1717 Wakonade Drive East Minneapolis, MN 55401 Welch, MN 55089 Michael B. Sellman Manager - Environmental Protection Division President and Chief Executive Officer Minnesota Attorney Generals Office Nuclear Management Company, LLC 445 Minnesota St., Suite 900 700 First Street St. Paul, MN 55101-2127 Hudson, MI 54016 U.S. Nuclear Regulatory Commission Craig G. Anderson Resident Inspector's Office Senior Vice President, Group Operations 1719 Wakonade Drive East Nuclear Management Company, LLC Welch, MN 55089-9642 700 First Street Hudson, WI 54016 Regional Administrator, Region III U.S. Nuclear Regulatory Commission Mr. Thomas J. Palmisano Suite 210 Site Vice President 2443 Warrenville Road Prairie Island Nuclear Generating Plant Lisle, IL 60532-4351 Nuclear Management Company, LLC 1717 Wakonade Drive East Administrator Welch, MN 55089 Goodhue County Courthouse Box 408 Red Wing, MN 55066-0408 Commissioner Minnesota Department of Commerce 85 7th Place East, Suite 500 St. Paul, MN 55101-2198

SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION USE OF ASME CODE CASE N-513-2 NUCLEAR MANAGEMENT COMPANY, LLC FPL ENERGY DUANE ARNOLD, LLC DUANE ARNOLD ENERGY CENTER MONTICELLO NUCLEAR GENERATING PLANT PALISADES NUCLEAR PLANT POINT BEACH NUCLEAR PLANT, UNITS 1 AND 2 PRAIRIE ISLAND NUCLEAR GENERATING PLANT, UNITS 1 AND 2 DOCKET NOS. 50-331, 50-263, 50-255, 50-266, 50-301, 50-282 and 50-306

1.0 INTRODUCTION

Nuclear Management Company, LLCs (NMCs) letter of December 12, 2005, requested Nuclear Regulatory Commission (NRC) approval of a relief request to use the alternative requirements of American Society of Mechanical Engineers (ASME) Code Case N-513-2, "Evaluation Criteria for Temporary Acceptance of Flaws in Moderate Energy Class 2 or 3 Piping," in lieu of Subarticle IWA-4000 of the ASME Boiler and Pressure Vessel Code (ASME Code),Section XI, Rules for Inservice Inspection of Nuclear Power Plant Components. This relief request applied to the following nuclear units:

  • Duane Arnold Energy Center
  • Monticello Nuclear Generating Plant
  • Palisades Nuclear Plant
  • Point Beach Nuclear Plant, Units 1 and 2
  • Prairie Island Nuclear Generating Plant, Units 1 and 2 On January 27, 2006, the NRC issued Amendment No. 260 transferring of the license for Duane Arnold Energy Center to FPL Energy Duane Arnold, LLC. Accordingly, this authorization applies to both NMC and FPL Energy Duane Arnold, LLC.

ENCLOSURE

2.0 REGULATORY EVALUATION

The inservice inspection (ISI) of the ASME Code Class 1, Class 2, and Class 3 components is to be performed in accordance with the ASME Code,Section XI, 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). Paragraph 50.55a(g)(6)(i) of Title 10 of the Code of Federal Regulations (10 CFR), states that The Commission will evaluate determinations . . . that [ASME] code requirements are impractical. The Commission may grant such relief and may impose such alternative requirements as it determines is authorized by law and will not endanger life or property or the common defense and security, and is otherwise in the public interest giving due consideration to the burden upon the licensee that could result if the requirements were imposed on the facility.

Pursuant to paragraph 10 CFR 50.55a(a)(3), alternatives to the requirements of paragraph (g) may be used, when authorized by the NRC, if the applicant 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 paragraph 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, to the extent practical within the limitations of design, geometry, and materials of construction of the components. Paragraph 10 CFR 50.55a(g)(4) requires that inservice examination of components and system pressure tests conducted during the first 10-year inspection interval and subsequent inspection intervals comply with the requirements in the latest edition and addenda of Section XI of the ASME Code. The latest edition and addenda of Section XI of the ASME Code is incorporated by reference in paragraph 10 CFR 50.55a(b), 12 months prior to the start of the 10-year inspection interval.

3.0 NMCS RELIEF REQUEST 3.1 ASME Code Component(s) Affected ASME Section XI, Moderate Energy Class 2 and Class 3 Piping.

3.2 Applicable ASME,Section XI, Code Edition and Addenda Plants Inservice Inspection Repair/Replacement Monticello 1995 Edition with the 1996 2001 Edition Addenda Prairie Island 1998 Edition with the 2000 1998 Edition with the 2000 Addenda Addenda Point Beach 1998 Edition with the 2000 1998 Edition with the 2000 Addenda Addenda Palisades 1989 Edition 1989 Edition

Duane Arnold 1989 Edition 1992 Edition with the 1992 Addenda 3.3 Applicable ASME Code Requirements NMC presented the following requirements of the 1989 Edition of the ASME Code,Section XI, for Class 3 and Class 2 piping:

CLASS 3 IWD-3000 states, This article is in course of preparation. The rules of IWB-3000 may be used."

IWB-3132 provides four ways in which an inservice volumetric or surface examination may be accepted.

1. IWB-3132.1, Acceptance by Volumetric or Surface Examination
2. IWB-3132.2, Acceptance by Repair
3. IWB-3132.3, Acceptance by Replacement
4. IWB-3132.4, Acceptance by Analytical Evaluation IWB-3132.2 states, Components whose volumetric or surface examination reveals flaws that exceed the acceptance standards listed in Table IWB-3410-1 shall be unacceptable for continued service until the additional examination requirements of IWB-2430 are satisfied, and the flaw shall be either removed by mechanical methods or the component repaired to the extent necessary to meet the acceptance standards of IWB-3000.

IWB-3132.3 states, As an alternative to the repair requirement of IWB-3132.2, the component or the portion of the component containing the flaw shall be replaced.

IWB-3142 provides five ways in which an inservice visual examination may be accepted.

1. IWB-3142.1, Acceptance by Visual Examination
2. IWB-3142.2, Acceptance by Supplemental Examination
3. IWB-3142.3, Acceptance by Corrective Measures or Repairs
4. IWB-3142.4, Acceptance by Analytical Evaluation
5. IWB-3142.5, Acceptance by Replacement IWB-3142.3 states, Components containing relevant conditions shall be acceptable for continued service if the relevant conditions are corrected or the components are repaired to the extent necessary to meet the acceptance standards specified in Table IWB-3410-1.

IWB-3142.5 states, As an alternative to either the supplemental examinations of IWB-3142.2, the corrective measures or repairs of IWB-3142.3, or the evaluation of IWB-3142.4, the component or that part of the component containing the relevant condition shall be replaced.

CLASS 2 IWC-3122 provides four ways in which an inservice volumetric and surface examination may be accepted.

1. IWC-3122.1, Acceptance by Examination
2. IWC-3122.2, Acceptance by Repair
3. IWC-3122.3, Acceptance by Replacement
4. IWC-3122.4, Acceptance by Evaluation IWC-3122.2 states, Components whose examination reveals flaws that exceed the acceptance standards listed in Table IWC-3410-1 shall be unacceptable for continued service until the additional examination requirements of IWC-2430 are satisfied, and the flaw shall be either removed by mechanical methods or the component repaired to the extent necessary to meet the acceptance standards of IWC-3000.

IWC-3122.3 states, As an alternative to the repair requirements of IWC-3122.2, a component or the portion of the component containing the flaw shall be replaced.

IWC-3132 provides four ways in which an inservice visual examination may be accepted.

1. IWC-3132.1, Acceptance by Supplemental Examination
2. IWC-3132.2, Acceptance by Corrective Measures or Repairs
3. IWC-3132.3, Acceptance by Evaluation
4. IWC-3132.4, Acceptance by Replacement IWC-3132.2 states, Components containing relevant conditions shall be acceptable for continued service if the relevant conditions are corrected or the components are repaired to the extent necessary to meet the acceptance standards specified in Table IWC-3410-1.

IWC-3132.4 states, As an alternative to the supplemental examinations of IWC-3132.1, the corrective measures or repairs of IWC-3132.2, or the evaluation of IWC-3132.3, a component or part of a component containing the relevant condition shall be replaced.

The requirements of the 1995 Edition with the 1996 Addenda are similar to the requirements of the 1998 Edition with the 2000 Addenda. NMC presented the requirements for Class 3 and Class 2 piping as follows:

CLASS 3 IWD-3000 states, This Article is in course of preparation. The rules of IWB-3000 may be used.

IWB-3132 provides three ways in which an insewice volumetric or surface examination may be accepted.

1. IWB-3132.1, Acceptance by Volumetric or Surface Examination,
2. IWB-3132.2, Acceptance by Repair/Replacement Activity, or
3. IWB-3132.3, Acceptance by Analytical Evaluation.

IWB-3132.2 states, A component whose volumetric or surface examination detects flaws that exceed the acceptance standards of Table IWB-3410-1 is unacceptable for continued service until the additional examination requirements of IWB-2430 are satisfied and the component is corrected by a repair/replacement activity to the extent necessary to meet the acceptance standards of IWB-3000.

IWB-3142 provides four ways in which an inservice visual examination may be accepted.

1. IWB-3142.1, Acceptance by Visual Examination
2. IWB-3142.2, Acceptance by Supplemental Examination
3. IWB-3142.3, Acceptance by Corrective Measures or Repair/Replacement Activity
4. IWB-3142.4, Acceptance by Analytical Evaluation IWB-3142.3 states, A component containing relevant conditions is acceptable for continued service if the relevant conditions are corrected by a repair/replacement activity or by corrective measure to the extent necessary to meet the acceptance standards of Table IWB-3410-1.

Class 2 Piping IWC-3122 provides three ways in which an inservice volumetric and surface examinations may be accepted.

1. IWC-3122.1, Acceptance by Examination
2. IWC-3122.2, Acceptance by Repair/Replacement Activity
3. IWC-3122.3, Acceptance by Analytical Evaluation IWC-3122.2 states, A component whose examination detects flaws that exceed the acceptance standards of Table IWC-3410-1 is unacceptable for continued service until the additional examination requirements of IWC-2430 are satisfied and the component is corrected by a repair/replacement activity to the extent necessary to meet the acceptance standards of IWC-3000.

IWC-3132 provides four ways in which an inservice visual examinations may be accepted.

I. IWC-3132, Acceptance

2. IWC-3132.1, Acceptance by Supplemental Examination
3. IWC-3132.2, Acceptance by Corrective Measures or Repair/Replacement Activity
4. IWC-3132.3, Acceptance by Analytical Evaluation IWC-3132.2 states, A component containing relevant conditions is acceptable for continued service if the relevant conditions are corrected by a repair/replacement activity

or by corrective measures to the extent necessary to meet the acceptance standards of Table IWC-3410-1.

3.4 NMCs Basis For The Relief Request NMC stated that relief is requested from replacement or internal weld repair of wall thinning conditions resulting from various wall thinning degradation mechanisms such as erosion, corrosion, cavitation, and pitting in moderate energy Class 2 and 3 piping systems in accordance with the design specification and the original construction code.

NMC stated that the NRC in RG 1.147, Revision 14, has accepted Code Case N-513-1 with the following limitations:

1. Specific safety factors in paragraph 4.0 must be satisfied.
2. Code Case N-513 may not be applied to:
i. components other than pipe and tube ii. leakage through a gasket iii. threaded connections employing nonstructural seal welds for leakage prevention (through seal weld leakage is not a structural flaw; thread integrity must be maintained) iv. degraded socket welds Code Case N-513-1 permits flaws in Class 2 and 3 moderate-energy piping on a temporary basis until the next outage if it can be demonstrated that adequate pipe integrity and leakage containment are maintained. The Code Case currently applies to part-through and through-wall planar flaws and part-through nonplanar flaws. Service experience has shown that some piping can suffer degradation from nonplanar flaws, such as pitting and microbiological attack, where leakage can occur. The Code Case can be used for nonplanar through-wall flaws, but in a restrictive situation where nonplanar geometry is dominant in one plane.

According to NMC, some plants have used the intent of Code Case N-513 for nonplanar leaking flaws. However, relief requests from code requirements are still required because of the limited scope of Code Case N-513. Code Case N-513-2 has expanded the application to cover all types of nonplanar flaws. The analysis procedures were expanded to address the general case of through-wall degradation. Code Case N-513-2 incorporates improved flaw evaluation procedures for piping that are provided in Appendix C to the 2002 Addenda of the ASME Code,Section XI. Code Case N-513-2 addresses the limitations posed in RG 1.147 as follows:

1. Paragraph 4.0 was revised to incorporate references to Appendix C for acceptance and eliminated the provision that lower safety factors may be used.
2. 1.0(a) was revised to limit the application of the code case as specified in the limitation applied in RG 1.147.

3.5 Duration of Proposed Alternative NMC requested approval of Code Case N-513-2 to be used for the 10-year ISI intervals for the plants as shown in the table below, or until the NRC publishes Code Case N-513-2 in a future

revision of RG 1.147.

Plant ISI Interval Dates Interval Monticello Fourth May 1, 2003 to May 31, 2012 Prairie Island 1 & 2 Fourth December 21, 2004 to December 20, 2014 Point Beach 1 & 2 Fourth July 1, 2002 to June 30, 2012 Palisades Third May 12, 1995 to May 12, 2006 Duane Arnold Third November 1, 1996 to October 31, 2006

4.0 TECHNICAL EVALUATION

As indicated in the above ASME Code,Section XI, requirements, flaws detected in Class 2 and 3 piping need to be either removed by repair/replacement, or accepted by analysis or acceptance criteria of the ASME Code. In the mid-1990's, the industry proposed temporary measures to accept and manage flaws in service for Class 3 piping. On August 14, 1997, the ASME issued the original Code Case N-513 to permit temporary acceptance of flaws in moderate energy Class 3 piping for operation without repair/replacement of degraded pipe.

On March 28, 2001, the ASME issued Code Case N-513-1 which permits Class 2 and Class 3 piping to accept the flaws in service temporarily without repair/replacement. Code Case N-513-1 also includes a revised flaw evaluation methodology. As stated in NMCs basis above, the staff has accepted Code Case N-513-1 in RG 1.47, Revision 14, with conditions. The staffs conditions are related to safety factors and the scope of applicability of the code case.

On February 20, 2004, the ASME issued Code Case N-513-2. However, the staff has not approved Code Case N-513-2 in RG 1.147, Revision 14, nor in 10 CFR 50.55a.

The staff has reviewed changes between Code Case N-513-1 and Code Case N-513-2. The staff confirms that Code Case N-513-2 has incorporated the conditions imposed in RG 1.147, Revision 14. As discussed above, Code Case N-513-2 has incorporated the flaw evaluation procedures for piping that are specified in Appendix C to the 2002 Addenda of the ASME Code,Section XI. The staff has approved the 2002 Addenda of the ASME Code in 10 CFR 50.55a.

Therefore, the use of the flaw evaluation methodology in Appendix C to the 2002 Addenda is acceptable.

The staff notes that although the degraded pipe is permitted to operate per Code Case N-513-2, the degraded piping is required to be repaired or replaced during the subsequent refueling outage in accordance with appropriated Section III and/or Section XI of the ASME Code.

Although flaws are allowed to remain in service, Code Case N-513-2 provides requirements to assure piping integrity. Code Case N-513-2 requires frequent inspections of no longer than

30-day intervals to determine if the flaw is growing and to establish the time at which the flaw will reach the allowable size. For through-wall leaking flaws, the code case requires daily walkdowns to confirm that the analysis conditions used in the evaluation remain valid. In addition, the Code Case requires augmented volumetric examination or physical measurement to assess degradation of affected system. The Code Case requires expansion in the inspection scope by increasing the sample size. If the inspections show that the flaw growth rate to be unacceptable, the Code Case requires immediate repair or replacement. Code Case N-513-2 also provides a rigorous methodology and acceptance criteria to evaluate the flaw. NMC and FPL Energy Duane Arnold, LLC are committed to adhere to all of the requirements in Code Case N-513-2.

On the basis of the above evaluation, the staff finds that in lieu of ASME Code,Section XI, IWA-4000, the proposed alternative requirements of Code Case N-513-2 provide an acceptable level of quality and safety.

5.0 CONCLUSION

On the basis of the staffs review of the submitted information, the staff concludes that the proposed alternatives in ASME Code,Section XI, Code Case N-513-2, as discussed in the request for relief will provide an acceptable level of quality and safety. Code Case N-513-2 contains requirements to maintain piping structural integrity, and incorporates the conditions listed in RG 1.147, Revision 14. Use of the Code Case is authorized until such time as the Code case is published in a future version of RG 1.147, and incorporated by reference in 10 CFR 50.55a(b). At that time, if NMC or FPL Energy Duane Arnold, LLC intends to continue implementing this Code case, it must follow all provisions of Code Case N-513-2 with conditions as specified in RG 1.147, and limitations as specified in Sections 50.55a(b)(4),

(b)(5), and (b)(6), if any.

Pursuant to 10 CFR 50.55a(a)(3)(i), the proposed alternative is authorized for the performance of piping evaluations to determine whether temporary continued operation of applicable ASME Code Class 2 and 3 piping system is allowed. This authorization applies to Duane Arnold, Monticello, Prairie Island, Units 1 and 2, Point Beach, Units 1 and 2, and Palisades for the remainder of the 10-year ISI interval of the respective units as noted in the relief request. All other requirements of the ASME Code, Sections 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: J. Tsao Date: July 3, 2006

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