ML102080017

Safety Evaluation Regarding Bulletin 2004-01,Inspection of Alloy 82/182/600 Materials Used in the Fabrication of Pressurizer Penetrations and Steam Space Piping Connections at Pressurized-Water Reactors

ML102080017
Person / Time
Site:	Watts Bar
Issue date:	08/04/2010
From:	Shawn Campbell Watts Bar Special Projects Branch
To:	Bhatnagar A Tennessee Valley Authority
Lamb John G./NRR/DORL, 415-3100
References
TAC MD6714
Download: ML102080017 (6)

Text

August 4, 2010 Mr. Ashok Bhatnagar Senior Vice President Nuclear Generation Development and Construction 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801

SUBJECT:

WATTS BAR NUCLEAR PLANT, UNIT 2 - SAFETY EVALUATION REGARDING BULLETIN 2004-01, "INSPECTIONS OF ALLOY 82/182/600 MATERIALS USED IN THE FABRICATION OF PRESSURIZER PENETRATIONS AND STEAM SPACE PIPING CONNECTIONS AT PRESSURIZED-WATER REACTORS" (TAC NO. MD6714)

Dear Mr. Bhatnager:

By letter dated September 7, 2007 (Agencywide Document and Access Management System Accession No. ML072570676) and supplemented on September 29, 2008 (ML082750518) and April 1, 2010 (ML100950044), the Tennessee Valley Authority (TVA) submitted a response to U.S. Nuclear Regulatory Commission (NRC) Bulletin 2004-01, "Inspections of Alloy 82/182/600 Materials Used in the Fabrication of Pressurizer Penetrations and Steam Space Piping Connections at Pressurized-Water Reactors," for Watts Bar Nuclear Plant, Unit 2.

The NRC staff has reviewed TVAs response. Enclosed is the NRC staffs safety evaluation; this completes the staffs efforts for TAC No. MD6714.

Sincerely,

/RA/

Stephen J. Campbell, Chief Watts Bar Special Projects Branch Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-391

Enclosure:

Safety Evaluation

Mr. Ashok Bhatnagar Senior Vice President Nuclear Generation Development and Construction 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801

SUBJECT:

WATTS BAR NUCLEAR PLANT, UNIT 2 - SAFETY EVALUATION REGARDING BULLETIN 2004-01, "INSPECTIONS OF ALLOY 82/182/600 MATERIALS USED IN THE FABRICATION OF PRESSURIZER PENETRATIONS AND STEAM SPACE PIPING CONNECTIONS AT PRESSURIZED-WATER REACTORS" (TAC NO. MD6714)

Dear Mr. Bhatnager:

By letter dated September 7, 2007 (Agencywide Document and Access Management System Accession No. ML072570676) and supplemented on September 29, 2008 (ML082750518) and April 1, 2010 (ML100950044), the Tennessee Valley Authority (TVA) submitted a response to U.S. Nuclear Regulatory Commission (NRC) Bulletin 2004-01, "Inspections of Alloy 82/182/600 Materials Used in the Fabrication of Pressurizer Penetrations and Steam Space Piping Connections at Pressurized-Water Reactors," for Watts Bar Nuclear Plant, Unit 2.

The NRC staff has reviewed TVAs response. Enclosed is the NRC staffs safety evaluation; this completes the staffs efforts for TAC No. MD6714.

Sincerely,

/RA/

Stephen J. Campbell, Chief Watts Bar Special Projects Branch Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-391

Enclosure:

Safety Evaluation DISTRIBUTION:

PUBLIC RidsNRRDorlWbsp RidsNrrPMWattsBar2 Resources RidsAcrs_MailCTR Resources RidsNrrDorlDpr Resources RidsOgcRp Resources RidsRgn2MailCenter Resources RidsNrrDorlLpwb Resources LRaghavan RidsNrrLABClayton Resources EAndruszkiewicz ADAMS ACCESSION NO: ML102080017 OFFICE DORL/WBSP/PM DORL/WBSP/LA DORL/WBSP/PM DORL/WBSP/BC NAME JLamb BClayton JWiebe SCampbell DATE 07/ 27 /10 07/ 27 /10 08/ 02 /10 08 / 04 /10 OFFICIAL RECORDS COPY

SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO BULLETIN 2004-01, "INSPECTIONS OF ALLOY 82/182/600 MATERIALS USED IN THE FABRICATION OF PRESSURIZER PENETRATIONS AND STEAM SPACE PIPING CONNECTIONS AT PRESSURIZED-WATER REACTORS" TENNESSEE VALLEY AUTHORITY WATTS BAR NUCLEAR PLANT, UNIT 2 DOCKET NO. 50-391

1.0 INTRODUCTION

In a letter dated September 7, 2007 (Agencywide Document and Access Management System Accession No. ML072570676), as supplemented on September 29, 2008 (Accession No. ML082750518) and April 1, 2010 (ML100950044), the Tennessee Valley Authority (TVA) submitted responses to U.S. Nuclear Regulatory Commission (NRC) Bulletin (BL) 2004-01, "Inspections of Alloy 82/182/600 Materials Used in the Fabrication of Pressurizer Penetrations and Steam Space Piping Connections at Pressurized-Water Reactors," that are applicable for Watts Bar Nuclear Plant (WBN), Unit 2.

2.0 BACKGROUND

On May 28, 2004, the NRC issued BL 2004-01 to the industry. BL 2004-01 informed addressees that current methods of inspecting the pressurizer penetrations and steam space piping connections fabricated from Alloy 82/182/600 materials may need to be supplemented with additional measures (e.g., bare-metal visual inspections) to detect pressurizer penetration and steam space piping connection flaws or leakage.

BL 2004-01 requested addressees to provide the NRC with information related to the materials of construction, the inspections that have been performed, and the inspections that will be performed to verify the integrity of the pressurizer penetrations and steam space piping connections.

Enclosure

3.0 REGULATORY EVALUATION

The general design criteria (GDC) establish the necessary design, fabrication, construction, testing, and performance requirements for structures, systems and components important to safety. The applicable GDC for Bulletin 2004-01 include GDC 14, Reactor Coolant Pressure Boundary (RCPB), GDC 31, Fracture Prevention of Reactor Coolant Pressure Boundary, and GDC 32, Inspection of Reactor Coolant Pressure Boundary. GDC 14 specifies that the RCPB be designed, fabricated, erected, and tested so as to have an extremely low probability of abnormal leakage, of rapidly propagating failure, and of gross rupture. GDC 31 specifies that the probability of rapidly propagating fracture of the RCPB be minimized. GDC 32 specifies that components that are part of the RCPB have the capability of being periodically inspected to assess their structural and leaktight integrity.

NRC regulations at Title 10 of the Code of Federal Regulations (10 CFR) Section 50.55a state that American Society of Mechanical Engineers (ASME) Code Class 1 components (which include the RCPB) must meet the requirements of Section XI of the ASME Code. Various portions of the ASME Code address RCPB inspection. For example, Table IWB-2500-1 of Section XI of the ASME Code provides examination requirements during system leakage testing of all pressure-retaining components of the RCPB and references IWB-3522 for acceptance standards. IWB-3522.1(c) and (e) specify that conditions requiring correction include the detection of leakage from insulated components and discoloration or accumulated residue on the surfaces of components, insulation, or floor areas that may be evidence of borated water leakage, with leakage defined as the through-wall leakage that penetrates the pressure retaining membrane. Therefore, 10 CFR 50.55a, by reference to the ASME Code, does not permit through-wall degradation of pressurizer penetrations and steam space piping connections. For through-wall leakage identified by visual examinations in accordance with the ASME Code, acceptance standards for the identified degradation are provided in IWB-3142.

Specifically, supplemental examination (by surface or volumetric examination), corrective measures or repairs, analytical evaluation, and replacement provide methods for determining the acceptability of degraded components.

Criterion V (Instructions, Procedures, and Drawings) of Appendix B to 10 CFR Part 50 states that activities affecting quality shall be prescribed by documented instructions, procedures, or drawings of a type appropriate to the circumstances and shall be accomplished in accordance with these instructions, procedures, or drawings. Criterion V further states that instructions, procedures, or drawings shall include appropriate quantitative or qualitative acceptance criteria for determining that important activities have been satisfactorily accomplished. Visual and volumetric examinations of the RCPB are activities that should be documented in accordance with these requirements.

Criterion IX (Control of Special Processes) of Appendix B to 10 CFR Part 50 states that special processes, including nondestructive testing, shall be controlled and accomplished by qualified personnel using qualified procedures in accordance with applicable codes, standards, specifications, criteria, and other special requirements.

Criterion XVI (Corrective Action) of Appendix B to 10 CFR Part 50 states that measures shall be established to assure that conditions adverse to quality are promptly identified and corrected.

For significant conditions adverse to quality, the measures taken shall include root cause determination and corrective action to preclude repetition of the adverse conditions.

4.0 TECHNICAL EVALUATION

By letter dated September 7, 2007, as supplemented on September 29, 2008 and April 1, 2010, TVA provided its responses to Items 1a, 1b, 1c, and 1d of BL 2004-01 for WBN Unit 2. TVA=s responses described its materials of fabrication and inspection programs for pressurizer penetrations and steam space piping at WBN Unit 2.

TVA=s response to Item 1a reported that some of the materials used in the fabrication of the pressurizer penetrations and steam space piping connections were Alloy 82/182/600 materials.

This reply required TVA to provide further responses to the remaining items in BL 2004-01.

In response to Item 1b, TVA stated that, prior to placing the pressurizer inservice, TVA WBN Unit 2 committed to perform a nondestructive examination (NDE) of the Pressurizer Power Operated Relief Valve connections, the safety relief valve connections, the spray line nozzle, and the surge line nozzle connections. TVA will apply the Mechanical Stress Improvement Process to the same components followed by another NDE of the same components.

In response to Item 1c, TVA provided a description of the Alloy 82/182/600 pressurizer penetration and steam space piping connection inspection program that will be implemented at WBN Unit 2 during the next and subsequent refueling outages. The description included the items to be inspected; the percent coverage that would be performed at each location; the inspection methods to be used; the qualification standards for the inspection methods and personnel; the process used to resolve any inspection indications; the inspection documentation to be generated; and the basis for concluding that WBN Unit 2 will satisfy the applicable regulatory requirements related to the structural and leakage integrity of pressurizer penetrations and steam space piping connections. If leaking pressurizer penetrations or steam space piping connections are found, TVA indicated that followup NDE will be performed to characterize flaws in the leaking penetrations. TVA provided its plans for expansion of the scope of NDE to be performed if circumferential flaws are found in any portion of the leaking pressurizer penetrations or steam space piping connections.

In response to Item 1d, TVA explained why the inspection program identified in the response to Item 1c is adequate for the purpose of maintaining the integrity of the WBN Unit 2 RCPB and for meeting all applicable regulatory requirements that pertain to the WBN Unit 2 facility.

5.0 CONCLUSION

The NRC staff finds that TVAs response to the BL 2004-01 is acceptable based on TVA adequately addressing the items in the bulletin for WBN Unit 2. The NRC staff also concludes that TVAs compliance with the regulatory requirements, the ASME Code,Section XI inspection requirements, and its commitment to continue performing NDE provides reasonable assurance that the RCPB integrity at WBN Unit 2 will be maintained.

Principal Contributor: Edward V. Andruszkiewicz Date: August 4, 2010