ML081680317

Approval of Request for Relief No. ANO 1-ISI-010 for the Third 10-Year Inservice Inspection Interval

ML081680317
Person / Time
Site:	Arkansas Nuclear
Issue date:	07/23/2008
From:	Balwant Singal NRC/NRR/ADRO/DORL/LPLIV
To:	Entergy Operations
Wang, A B, NRR/DORL/LPLIV, 415-1445
References
TAC MD8017
Download: ML081680317 (7)

Text

July 23, 2008 Vice President, Operations Arkansas Nuclear One Entergy Operations, Inc.

1448 S.R. 333 Russellville, AR 72802

SUBJECT:

ARKANSAS NUCLEAR ONE, UNIT NO. 1 - APPROVAL OF REQUEST FOR RELIEF NO. ANO1-ISI-010 FOR THE THIRD 10-YEAR INSERVICE INSPECTION INTERVAL (TAC NO. MD8017)

Dear Sir or Madam:

By a letter dated January 22, 2008 to the U.S. Nuclear Regulatory Commission (NRC), Entergy Operations, Inc. (Entergy, the licensee) submitted Request for Relief Nos. ANO1-ISI-009, ANO1-ISI-010, and ANO1-ISI-011 for the remainder of the Third 10-year Inservice Inspection Interval at Arkansas Nuclear One, Unit No. 1. By letter dated April 18, 2008, the licensee withdrew its Request for Relief No. ANO1-ISI-011. Request for Relief No. ANO1-ISI-009 is still under NRC staff review. Request for Relief No. ANO1-ISI-009 proposes to use a root mean square error value of 0.189" in lieu of 0.125" as required by Code Case N-695 Qualification Requirements for Dissimilar Metal Piping Welds, American Society of Mechanical Engineers Code,Section XI. The value is used for the depth sizing of flaws in dissimilar metal weld test specimens during qualification of ultrasonic examination procedure, equipment and personnel.

The NRC staff completed its review of the subject request for relief. Based on the enclosed safety evaluation (SE), the NRC staff determined that the proposed Request for Relief ANO1-ISI-010, will provide an acceptable level of quality and safety. Therefore, pursuant to paragraph 50.55a(a)(3)(i) of Title 10 of the Code of Federal Regulations, the NRC staff authorizes the use of Relief Request ANO1-ISI-010 at ANO-1.

If you have any questions regarding the SE, please contact Alan B. Wang at (301) 415-1445.

Sincerely,

/RA/

Balwant K. Singal, Acting Chief Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-313

Enclosure:

Safety Evaluation cc w/encl: See next page

ML081680317 *SE Input Memo, **NLO w/comments OFFICE NRR/LPL4/PM NRR/LPL4/LA DCI/CPNB/BC OGC NRR/LPL4/BC (A) NRR/LPL4/PM NAME AWang GLappert TChan* RVHolmes (**) BSingal AWang DATE 6/27/08 6/27/08 04/03/2008 7/2/08 7/18/08 7/23/08 Arkansas Nuclear One (2/25/08) cc:

Senior Vice President Section Chief, Division of Health Entergy Nuclear Operations Radiation Control Section P.O. Box 31995 Arkansas Department of Health and Jackson, MS 39286-1995 Human Services 4815 West Markham Street, Slot 30 Vice President, Oversight Little Rock, AR 72205-3867 Entergy Nuclear Operations P.O. Box 31995 Section Chief, Division of Health Jackson, MS 39286-1995 Emergency Management Section Arkansas Department of Health and Senior Manager, Nuclear Safety Human Services

& Licensing 4815 West Markham Street, Slot 30 Entergy Nuclear Operations Little Rock, AR 72205-3867 P.O. Box 31995 Jackson, MS 39286-1995 Pope County Judge Pope County Courthouse Senior Vice President 100 W. Main Street

& Chief Operating Officer Russellville, AR 72801 Entergy Operations, Inc.

P.O. Box 31995 Senior Resident Inspector Jackson, MS 39286-1995 U.S. Nuclear Regulatory Commission P.O. Box 310 Associate General Counsel London, AR 72847 Entergy Nuclear Operations P.O. Box 31995 Regional Administrator, Region IV Jackson, MS 39286-1995 U.S. Nuclear Regulatory Commission 611 Ryan Plaza Drive, Suite 400 Manager, Licensing Arlington, TX 76011-8064 Entergy Operations, Inc.

Arkansas Nuclear One 1448 SR 333 Russellville, AR 72802

SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION REQUEST FOR RELIEF ANO1-ISI-010 FROM THE AMERICAN SOCIETY OF MECHANICAL ENGINEERS BOILER AND PRESSURE VESSEL CODE, SECTION XI, THIRD 10-YEAR INSERVICE INSPECTION INTERVAL ENTERGY OPERATIONS, INC ARKANSAS NUCLEAR ONE UNIT 1 DOCKET NO. 50-313

1.0 INTRODUCTION

By a letter dated January 22, 2008 (Agencywide Document Access and Management System (ADAMS) Accession No. ML080250308) to the U.S. Nuclear Regulatory Commission (NRC),

Entergy Operations, Inc (Entergy, the licensee) submitted Request for Relief No. ANO1-ISI-010, for the remainder of the Third 10-year Interval Inservice Inspection Program of Arkansas Nuclear One, Unit 1 (ANO-1). The licensee requested to use a root mean square error value of 0.189" in lieu of 0.125" as required by Code Case N-695 Qualification Requirements for Dissimilar Metal Piping Welds American Society of Mechanical Engineers (ASME) Code,Section XI. This value is used for the depth sizing of flaws in dissimilar metal weld test specimens during qualification of ultrasonic examination procedure, equipment and personnel.

2.0 REGULATORY EVALUATION

Title 10 of the Code of Federal Regulations (10 CFR) 50.55a(g) requires that inservice inspection (ISI) of the ASME Code Class 1, 2, and 3 components be performed in accordance with Section XI of the ASME Code and applicable addenda, except where specific written relief has been granted by the Commission pursuant to 10 CFR 50.55a(g)(6)(i). In addition, according to 10 CFR 50.55a(a)(3), alternatives to the requirements of paragraph 50.55a(g) may be used, when authorized by the NRC if an applicant demonstrates that the proposed alternatives would provide an acceptable level of quality and safety or if the specified requirement 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, Rules for ISI 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 ISI 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 inspection interval, (or the optional ASME Code cases listed in NRC Regulatory Guide (RG)1.147, Revision 15, that are incorporated by reference in paragraph (b) of this section), subject to the limitations and modifications listed in paragraph (b) of this section.

The ISI Code of Record for the third 10-year inservice inspection interval for ANO-1 is the 1992 Edition of the ASME Code,Section XI.

3.0 TECHNICAL EVALUATION

3.1 SYSTEMS/COMPONENTS FOR WHICH RELIEF IS REQUESTED Core Flood Safe-End to Nozzle Welds, Nos: 01-025 and 01-026 Code Class: Class 1

Reference:

ASME Code,Section XI, 1992 Edition with no Addenda and 1995 Edition with 1996 Addenda, Appendix VIII, Supplement 10 Examination Category: B-F Item Number: B5.10 Components: Reactor Vessel Nozzle to Safe End Butt Welds Unit/Inspection Interval Arkansas Nuclear One, Unit 1/Third 10-year Interval Applicability: 1R21 Refueling Outage 3.2 CODE REQUIREMENTS A volumetric examination of dissimilar metal pressure retaining piping welds is required per the 1989 Edition ASME Section XI Code, Table IWB-2500-1, Examination Category B-F, Item No.

B5.10. In addition, 10 CFR 50.55a requires that these examinations be performed using procedure, personnel, and equipment qualified in accordance with the requirements of the ASME Code,Section XI, 1995 Edition, 1996 Addenda, Appendix VIII, Supplement 10 Qualification Requirements for Dissimilar Metal Piping Welds. However, NRC in RG 1.147 Inservice Inspection Code Case acceptability, ASME Section XI, Division 1, Revision 15 has approved an alternative to the requirements of Appendix VIII, Supplement 10 in Section XI, Code Case N-695 Qualification Requirements for Dissimilar Metal Piping Welds.

3.3 LICENSEES PROPOSED ALTERNATIVE Entergy proposes to use Code Case N-695 with a root mean square error (RMSE) of 0.189 inches instead of the 0.125 inches specified for depth sizing in the code case. In the event an indication is detected that requires depth sizing, the 0.064 inch difference between the required RMSE and the demonstrated RMSE (0.189 inch - 0.125 inch = 0.064 inch) will be added to the measured through-wall extent of the detected indication for comparison with the applicable acceptance criteria. If the examination vendor demonstrates an improved depth sizing RMSE prior to the examination, the excess of that improved RMSE over the 0.125 inch RMSE requirement, if any, will be added to the measured value for comparison with applicable acceptance criteria.

The activities included in the request for relief are subject to third party review by the Authorized Nuclear Inservice Inspector.

3.4 LICENSEES BASIS FOR ALTERNATIVE ASME Code Case N-695, Qualification Requirements for Dissimilar Metal Piping Welds,Section XI, Division 1, is shown as acceptable to the NRC in RG 1.147 Inservice Inspection Code Case acceptability, ASME Section XI, Division 1, Revision 15 for application in licensees inservice inspection programs.

To date, although examination vendors have qualified for detection and length sizing on these welds, the examination vendors have not met the RMSE requirement for depth sizing. Entergys contracted examination vendor has demonstrated ability to meet the depth sizing qualification requirement with an RMSE of 0.189 inch instead of the 0.125 inch required by the code case.

The addition of the difference in allowable depth sizing tolerance as demonstrated to that actually measured during the examination to the flaw depths measured will compensate for the possible variance in the measured depth.

The proposed alternative assures that the safe end-to-nozzle welds will be fully examined by procedures, personnel, and equipment qualified by demonstration in all aspects except for depth sizing. For depth sizing, the proposed addition of the difference between the qualified and demonstrated sizing tolerance to any flaw required to be sized compensates for the potential variation. The proposed alternative provides an acceptable level of quality and safety in accordance with 10 CFR 50.55a(a)(3)(i).

4.0 NRC STAFF EVALUATION ASME Code Case N-695, Qualification Requirements for Dissimilar Metal Piping Welds,Section XI, Division 1, is shown as acceptable to the NRC in RG 1.147 Inservice Inspection Code Case acceptability, ASME Section XI, Division 1, Revision 15 for application in licensees inservice inspection programs. However, Code Case N-695 requires that examination procedures, equipment, and personnel meet specific criteria for accuracy of flaw depth sizing.

The code case under Paragraph 3.3(c) Depth-Sizing Test specifies that examination procedures, equipment, and personnel are qualified for depth-sizing when the RMS error of the flaw depth measurements, as compared to the true flaw depths, do not exceed 0.125 inch.

The 1995 Edition with 1996 Addenda of the ASME Code,Section XI, Appendix VIII, Supplement 10, Qualification Requirements for Dissimilar Metal Piping Welds has also specified under Paragraph 3.2(b) Sizing Acceptance Criteria that the examination procedures, equipment, and personnel are qualified for depth sizing when the RMSE of the flaw depth measurements, as compared to the true flaw depths, is less than or equal to 0.125". The industry is in the process of qualifying personnel to Supplement 10 as implemented by the Performance Demonstration Initiative program. However, for demonstrations performed from the inside surface of a pipe weldment, personnel have been unsuccessful at achieving the 0.125 inch RMSE depth sizing criterion. At this time, achieving the 0.125 inch RMSE appears to be extremely difficult. The vendor contracted by the licensee has only been able of achieving an accuracy of 0.189 inch RMSE. The licensee has proposed to use 0.189 inch RMSE to size any detected flaws during the forthcoming outage. The licensee would add the difference (0.064 inch) between the code case required RMSE (0.125 inch) and the demonstrated accuracy (0.189 inch RMSE) to the measurements acquired from flaw sizing. The request is applicable for 1R21 Refueling Outage and for the remainder of the third 10-year inservice inspection interval of ANO-1.

From performance demonstrations of typical hot leg and cold leg weld examinations with a wall thickness of 2.5 inches, the NRC staff gathered information which suggested that the RMSE values were independent of flaw depth. In the thickness range of test specimens, 0.125 inch RMSE of the flaw depth measurement would be approximately 5 percent tolerance on root mean square percent of the typical wall thickness and, likewise, 0.189 inch RMSE would translate to approximately 7.5 percent of the root mean square percent of the typical wall thickness.

The increase in error of 2.5 percent of the measured flaw depth is less than the planar flaw acceptance criteria in Table IWB-3514-2 of the ASME Code,Section XI. Further, the licensee has proposed to add the difference in allowable depth sizing tolerance as demonstrated to that actually measured during the examination to the flaw depths measured which would compensate for the possible variance in the measured depth. Therefore, the NRC staff has determined that the flaw depth adjustment proposed by the licensee would ensure a conservative bounding flaw depth value during performance demonstration and would provide an acceptable level of quality and safety.

5.0 CONCLUSION

Based on the above evaluation, the NRC staff has determined that achieving the 0.125 inch RMSE for depth sizing of flaws in dissimilar metal weld test specimens during qualification of ultrasonic examination procedure, equipment and personnel for the subject welds is extremely difficult at this time and instead, the licensees proposal to use a value of 0.189 inches RMSE would provide an acceptable level of quality and safety. Therefore, pursuant to 10 CFR 50.55a(a)(3)(i), the licensees proposed alternative is authorized for ANO-1 for the remainder of the third 10-year ISI interval. All other ASME Code,Section XI requirements for which relief was not specifically requested and approved in this relief request remain applicable, including third party review by the Authorized Nuclear Inservice Inspector.

Principal Contributor: P. Patniak Date: July 23, 2008