ML020440786

Relief Request for Authorization to Use Code Case N-516-2 as an Alternative to the American Society of Mechanical EngineersSection XI Requirements (Tac Nos. MB3722 and MB3723)

ML020440786
Person / Time
Site:	Susquehanna
Issue date:	02/21/2002
From:	Joel Munday NRC/NRR/DLPM/LPD1
To:	Byram R Susquehanna
Munday J, NRR/DLPM, 415-2330
References
TAC MB3722, TAC MB3723
Download: ML020440786 (8)

Text

February 21, 2002 Mr. Robert G. Byram Senior Vice President and Chief Nuclear Officer PPL Susquehanna, LLC 2 North Ninth Street Allentown, PA 18101

SUBJECT:

SUSQUEHANNA STEAM ELECTRIC STATION, UNITS 1 AND 2 - RELIEF REQUEST FOR AUTHORIZATION TO USE CODE CASE N-516-2 AS AN ALTERNATIVE TO THE ASME CODE, SECTION XI, REQUIREMENTS (TAC NOS. MB3722 AND MB3723)

Dear Mr. Byram:

In a letter dated January 2, 2002, PPL Susquehanna, LLC, the licensee for the Susquehanna Steam Electric Station, Units 1 and 2 (SSES 1 and 2), submitted Relief Request No. 25 (RR-25) for authorization to use American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code) Case N-516-2, Underwater Welding,Section XI, Division 1." The licensee submitted the request pursuant to Title 10 of the Code of Federal Regulations (10 CFR), Section 50.55a(a)(3)(i), as a proposed alternative to the requirements of ASME Code,Section XI, Rules for Inservice Inspection of Nuclear Power Plant Components.

The U.S. Nuclear Regulatory Commission (NRC) staff has reviewed the proposed relief request against the requirements of ASME Code,Section XI, 1992 Edition, Subsection IWA-4000, 1992 Addenda. The results of the review are provided in the enclosed safety evaluation (SE).

The NRC staff has concluded that the proposed alternative to the ASME Code requirements requested in RR-25, with the specified conditions, would provide an acceptable level of quality and safety. Therefore, the proposed alternative is authorized pursuant to 10 CFR 50.55a(a)(3)(i) for implementation for the second 10-year interval of the Inservice Inspection Program for SSES Units 1 and 2. As discussed with members of your staff, the authorization to use the alternative is based upon an additional two conditions and the implementation of the limitation specified by the licensee as described in Section 2.2 of the enclosed SE.

R. Byram If you have any questions, please contact your project manager, Timothy Colburn, at (301) 415-1402.

Sincerely,

/RA/

Joel T. Munday, Acting Chief, Section 1 Project Directorate I Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket Nos. 50-387 and 50-388

Enclosure:

Safety Evaluation cc w/encl: See next page

R. Byram If you have any questions, please contact your project manager, Timothy Colburn, at (301) 415-1402.

Sincerely,

/RA/

Joel T. Munday, Acting Chief, Section 1 Project Directorate I Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket Nos. 50-387 and 50-388

Enclosure:

Safety Evaluation cc w/encl: See next page DISTRIBUTION PUBLIC MO'Brien TTate BPlatchek, RGN-I PDI-1 Reading JMunday TBloomer TColburn EAdensam OGC ACRS AHiser GHill(4) CCowgill, RGN-I TBergman ACCESSION NO.: ML020440786 *SE provided on 2/8/02. No major changes made.

OFFICE PDI-2/PM PDI-1/PM PDI-2/LA OGC EMCB/SC* PDI-1/(A)SC NAME TTate TColburn MO'Brien RHoefling AHiser JMunday DATE 2/20/02 2/20/02 2/20/02 2/21/02 2/8/02 2/21/02 OFFICIAL RECORD COPY

SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO RELIEF REQUEST NO. 25 TO USE CODE CASE N-516-2 AS AN ALTERNATIVE TO THE AMERICAN SOCIETY OF MECHANICAL ENGINEERS (ASME)

SECTION XI, REQUIREMENTS PPL SUSQUEHANNA, LLC ALLEGHENY ELECTRIC COOPERATIVE, INC.

SUSQUEHANNA STEAM ELECTRIC STATION, UNITS 1 AND 2 DOCKET NOS. 50-387 AND 388

1.0 INTRODUCTION

The inservice inspection (ISI) of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code) Class 1, Class 2, and Class 3, components is to be performed in accordance with Section XI, Rules for Inservice Inspection of Nuclear Power Plant Components, of the ASME Code and applicable editions and addenda as required by Title 10 of the Code of Federal Regulations (10 CFR) Section 50.55a(g), except where specific written relief has been granted by the Commission pursuant to 10 CFR 50.55a(g)(6)(i). The regulations in 10 CFR 50.55a(a)(3) state, in part, that alternatives to the requirements of paragraph (g) may be used, when authorized by the U.S. Nuclear Regulatory Commission (NRC) staff, 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) shall 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. 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) twelve months prior to the start of the 120-month interval, subject to the limitations and modifications listed therein. The ISI Code of record for Susquehanna Steam Electric Station, Units 1 and 2 (SSES 1 and 2), for the second 10-year interval is the 1992 Edition and 1992 Addendum of the ASME Code. The components (including supports) may meet the requirements set forth in subsequent editions and addenda of the ASME Code incorporated by reference in 10 CFR 50.55a(b) subject to the limitations and modifications listed therein and subject to Commission approval.

In a letter dated January 2, 2002, the licensee requested relief from certain Code-required criteria. Specifically, the licensee proposed an alternative to perform a weld repair underwater according to ASME Code Case (CC) N-516-2, Underwater Welding,Section XI, Division 1, for the second 10-year interval of the Inservice Inspection Program for SSES Units 1 and 2. The NRC staff has reviewed the information submitted by the licensee as discussed below.

2.0 RELIEF REQUEST NO. 25, ASME CODE CASE (CC) N-516-2, UNDERWATER WELDING SECTION XI, DIVISION 1" 2.1 Code Requirement for which Relief is Requested The licensees repair and replacement code of record is the 1992 Edition with 1992 Addenda to Section XI of the ASME Code. ASME Code,Section XI, IWA-4000, Repair and Replacement, requirements apply. However, the ASME Code does not address the requirements for underwater welding repairs, nor does it provide requirements on welding P-No. 1 carbon steel components underwater.

2.2 Licensees Proposed Alternative to ASME Code Pursuant to 10 CFR 50.55a(a)(3)(i), in the January 2, 2002, letter, the licensee proposed implementing the provisions of CC N-516-2, with the following limitation:

When welding is to be performed on high neutron fluence Class 1 material, then a mockup, using material with similar fluence levels, should be welded to verify that adequate crack prevention measures were used.

The proposal is for the second 10-year ISI interval.

2.3 Licensees Basis for Alternative (as stated)

ASME [Code] Section XI, IWA-4000 (1992 edition with the 1992 addenda), does not address the requirements for welded repair or installation of replacement items by welding on ASME Class 1, 2, 3 and MC pressure boundary components when welding is performed underwater. To address this issue, ASME [Code] Section XI, has issued Code Case N-516-2, Underwater Welding. Code Case N-516-2 provides welding methods and requirements that may be used when welding for a repair or replacement activity is performed underwater.

Code Case N-516-1 was approved by the ASME Boiler and Pressure Vessel Code Committee on December 31, 1996. Code Case N-516-2 (approved on January 17, 2000) is the reaffirmation of Code Case N-516-1, except for a few minor editorial changes. Code Case N-516-2 is not yet endorsed in the most recent listing of NRC approved code cases provided in Regulatory Guide 1.147, Inservice Inspection Code Case Acceptability, ASME Section XI, Division 1. The original version of the Code Case, N-516, is endorsed in Revision 12 of Regulatory Guide 1.147. However, this version of the subject Code Case is only applicable for use on P-No. 8 and P-No. 4X materials. Revisions 1 and 2 of the Code Case extend the applicability to underwater repairs and replacements made on

components made of P-No. 1, carbon steel materials as well. Authorization to use the guidance provided in Revision 2 of the subject Code Case will allow the [S]SES to control the performance of underwater welding in accordance with an appropriate industry standard that will adequately assure weld integrity.

The Code Case will provide appropriate controls over the welding processes that are needed to implement such repairs, replacements, and modifications in a safe and effective manner. [S]SES therefore regards these requirements as providing an acceptable level of quality and safety.

2.4 Evaluation The ASME Code did not address underwater welding until the 1996 Addenda, when CC N-516 was approved. The NRC staff reviewed the 1996 Addenda in the process of updating 10 CFR 50.55a to incorporate, by reference, the 1995 Edition with the 1996 Addenda of the ASME Code. Revision 1 to CC N-516 added welding of P-No. 1, carbon steel to the CC. CC N-516-2 has been reviewed and accepted with conditions in the Draft Regulatory Guide (DG)-1091 (proposed Revision 13 of Regulatory Guide (RG) 1.147), "Inservice Inspection Code Case Acceptability, ASME Section XI, Division 1," currently issued for public comment (December 2001). CC N-516-2 provides guidelines for underwater welding of P-No. 1, P-No. 8 and P-No.

4X materials. P-No. 1 carbon steels are easier to weld than the austenitic steels approved in the original version of the CC. However, CC N-516-2 does not appropriately address the welder and procedure qualification relied upon to determine if the weld is degraded by hydrogen.

Paragraph 3.2 in CC N-516-2 allows for welder qualifications, a radiographic examination in lieu of a mechanical bend test on carbon steel (P-No. 1) if the mechanical bend test fails. This does not agree with ASME Code Section IX, "Welding and Brazing Qualification," wherein if a welder fails the mechanical bend test, then his/her retest shall be by mechanical bend test. Also, paragraph 5.0 in this CC allows Charpy V-Notch testing of carbon steel (P-No. 1) materials in lieu of the bend tests required for Welding Procedure Qualifications. This paragraph also does not agree with ASME Code,Section IX.

Underwater welding can be a high hydrogen process. Radiography and Charpy V-Notch tests generally cannot identify hydrogen embrittlement of steel materials. However, a slow bend test could possibly identify this problem. To address both of these issues, the NRC staff requires the following additional conditions in the use of CC N-516-2:

1. Performance qualifications shall be in accordance with Paragraph 3.2 in CC N-516-2, except that immediate retest following a failed mechanical bend test shall be in accordance with ASME Code,Section IX, QW-320.

2. Procedure qualification shall be in accordance with Paragraph 3.1 in CC N-516-2.

The Alternative Procedure Qualification Requirements of paragraph 5.0 shall not be used except as noted in Paragraph 4.(b)(4) for the additional requirements for qualification of filler metal.

These two conditions are necessary because the referenced paragraphs, i.e., paragraphs 3.2 and 5.0 in the CC, can eliminate the mechanical bend test requirements of ASME Code,Section IX. These bend tests are necessary because they can be helpful in recognizing whether the welds are prone to the harmful effects of hydrogen embrittlement and excessively hard weld deposits.

In the January 2, 2002, letter, the licensee stated the following limitation regarding use of the CC N-516-2:

When welding is to be performed on high neutron fluence Class 1 material, then a mockup, using material with similar fluence levels, should be welded to verify that adequate crack prevention measures were used.

The NRC staff concludes that, with the added conditions and limitation shown above, appropriate controls over the welding processes needed to implement such repairs, replacements, and modifications in a safe and effective manner are provided. Therefore, the NRC staff has determined that the use of CC N-516-2, as implemented by the licensee with the added conditions and limitation shown above for underwater welding, will adequately assure weld integrity.

3.0 CONCLUSION

Based on the discussion above, the NRC staff has concluded that the proposed alternative requested in RR-25 for the second 10-year interval, with the specified conditions and limitation, will provide an acceptable level of quality and safety. Therefore, pursuant to 10 CFR 50.55a(a)(3)(i), the NRC staff authorizes the proposed alternative for the second 10-year interval. CC N-516-2 has been reviewed and accepted with conditions in DG-1091 (proposed Revision 13 of RG 1.147). However, based on resolution of comments received on the proposed Revision 13 of RG 1.147, the conditions will be modified to include the 2 conditions identified above in the final Revision 13 of RG 1.147. Based on the above, the use of CC N-516-2 with the limitation specified by the licensee, and the two additional conditions is authorized until such time as the CC is published in a final revision 13 of RG 1.147. At that time, if the licensee intends to continue to implement CC N-516-2, the licensee is to follow all provisions in the CC including any limitations or conditions specified in Revision 13 to RG 1.147.

Principal Contributor: T. Bloomer Date: February 21, 2002

Susquehanna Steam Electric Station, Units 1 &2 Bryan A. Snapp, Esq Herbert D. Woodeshick Assoc. General Counsel Special Office of the President PPL Services Corporation PPL Susquehanna, LLC 2 North Ninth Street GENTW3 Rural Route 1, Box 1797 Allentown, PA 18101-1179 Berwick, PA 18603-0035 Rocco R. Sgarro George T. Jones Supervisor-Nuclear Licensing Vice President-Nuclear PPL Susquehanna, LLC Engineering & Support 2 North Ninth Street GENA61 PPL Susquehanna, LLC Allentown, PA 18101-1179 2 North Ninth Street, GENA61 Allentown, PA 18101-1179 Senior Resident Inspector U.S. Nuclear Regulatory Commission Dr. Judith Johnsrud P.O. Box 35, NUCSA4 National Energy Committee Berwick, PA 18603-0035 Sierra Club 443 Orlando Avenue Director-Bureau of Radiation Protection State College, PA 16803 Pennsylvania Department of Environmental Protection Board of Supervisors P.O. Box 8469 Salem Township Harrisburg, PA 17105-8469 P.O. Box 405 Berwick, PA 18603-0035 PPL Susquehanna, LLC Nuclear Records Allen M. Male Attn: G. DallaPalu Manager - Quality Assurance 2 North Ninth Street GENA62 PPL Susquehanna, LLC Allentown, PA 18101-1179 Two North Ninth Street, GENA92 Allentown, PA 18101-1179 Richard W. Osborne Allegheny Electric Cooperative, Inc. Terry L. Harpster 212 Locust Street Manager - Nuclear Regulatory Affairs P.O. Box 1266 PPL Susquehanna, LLC Harrisburg, PA 17108-1266 Two North Ninth Street, GENA61 Allentown, PA 18101-1179 Regional Administrator, Region 1 U.S. Nuclear Regulatory Commission Richard L. Anderson 475 Allendale Road General Manager - SSES King of Prussia, PA 19406 Susquehanna Steam Electric Station PPL Susquehanna, LLC Bryce L. Shriver Box 467, NUCSB3 Vice President-Nuclear Site Operations Berwick, PA 18603-0035 Susquehanna Steam Electric Station PPL Susquehanna, LLC Ronald L. Ceravolo Box 467, NUCSA4 General Manager - Plant Support Berwick, PA 18603-0035 Susquehanna Steam Electric Station PPL Susquehanna Steam Electric Station Box 467, NUCSA4 Berwick, PA 18603-0035