1CAN071202, Requests for Relief from American Society of Mechanical Engineers (ASME) Section XI Volumetric Examination Requirements, Fourth 10-Year Interval, First Period

Requests for Relief from American Society of Mechanical Engineers (ASME)Section XI Volumetric Examination Requirements, Fourth 10-Year Interval, First Period

ML12207A594
Person / Time
Site:	Arkansas Nuclear
Issue date:	07/25/2012
From:	Pyle S Entergy Operations
To:	Office of Nuclear Reactor Regulation, Document Control Desk
References
1CAN071202
Download: ML12207A594 (16)

Text

Entergy Operations, Inc.

1448 S.R. 333 Russellville, AR 72802 Tel 479-858-4704 Stephenie L. Pyle Manager, Licensing Arkansas Nuclear One 1CAN071202 July 25, 2012 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555

SUBJECT:

Requests for Relief from American Society of Mechanical Engineers (ASME)

Section XI Volumetric Examination Requirements Fourth 10-Year Interval, First Period Arkansas Nuclear One, Unit 1 Docket No. 50-313 License No. DPR-51

Dear Sir or Madam:

Pursuant to 10 CFR 50.55a(g)(6)(i), Entergy Operations, Inc. (Entergy) requests relief from the requirements of the ASME, Boiler and Pressure Vessel Code,Section XI pertaining to volumetric examinations at Arkansas Nuclear One, Unit 1 (ANO-1). In several locations it was determined that the examinations were impractical due to interference or geometry. Individual relief requests are provided in the attachments, divided by examination category.

10 CFR 50.55a(g)(5)(iv) requires that the basis for the determination of impracticality be submitted to the NRC for review and approval within 12 months after the expiration of the 120-month inspection interval. These reliefs are for the fourth ANO-1 10-year Inservice Inspection interval, first period. The interval and first period started on May 31, 2008. The first period ended May 30, 2011.

There are no new regulatory commitments made in this submittal.

If you have any questions or require additional information, please contact me.

Sincerely, Original signed by David B. Bice for S. L. Pyle SLP/rwc Attachments:

1. Request for Relief - ANO1-ISI-021

2. Request for Relief - ANO1-ISI-022

1CAN071202 Page 2 of 2 cc: Mr. Elmo E. Collins Regional Administrator U. S. Nuclear Regulatory Commission, Region IV 1600 East Lamar Boulevard Arlington, TX 76011-4511 NRC Senior Resident Inspector Arkansas Nuclear One P. O. Box 310 London, AR 72847 U. S. Nuclear Regulatory Commission Attn: Mr. Kaly Kalyanam MS O-8 B1 One White Flint North 11555 Rockville Pike Rockville, MD 20852 Mr. Bernard R. Bevill Arkansas Department of Health Radiation Control Section 4815 West Markham Street Slot #30 Little Rock, AR 72205

Attachment 1 to 1CAN071202 Request for Relief ANO1-ISI-021 to 1CAN071202 Page 1 of 5 REQUEST FOR RELIEF ANO1-ISI-021 Components / Pressurizer Nozzle Welds 012 and 05-013 Numbers:

Code Classes: American Society of Mechanical Engineers (ASME) Code Class 1

References:

ASME Section XI 2001 Edition w/ 2003 Addenda, Table IWB-2500-1 Code Case N-460 Examination Category: B-D Item Number(s) B3.110

==

Description:==

Full Penetration Welded Nozzles in Vessels - Inspection Program B Unit / Inspection Arkansas Nuclear One, Unit 1 (ANO-1) / Fourth (4th) 10-Year Interval Applicability: Interval, First (1st) Inspection Period I. CODE REQUIREMENTS ASME Section XI, Table IWB-2500-1, Examination Category B-D, Full Penetration Welded Nozzles in Vessels - Inspection Program B:

Item B3.110 requires a volumetric examination of Pressurizer Nozzle-to-Vessel Weld volume, as depicted in Figures IWB-2500-7(a) through (d), as applicable.

II. RELIEF REQUEST Pursuant to 10 CFR 50.55a(g)(6)(i), Entergy Operations, Inc. (Entergy) requests relief from achieving the Code-required coverage when performing volumetric examinations of the components identified in Table 1.

III. BASIS FOR RELIEF During ultrasonic examination of the non-Appendix VIII Pressurizer Nozzle-to-Vessel welds listed in Table 1, greater than 90% coverage of the required examination volume could not be obtained. Examinations were performed utilizing Entergy approved procedures specific to ferritic vessels greater than 2 inches in thickness.

Due to the geometric configuration of the components, effective volumetric examination could only be performed from the shell side of the welds. The use of 0, 45 and 60 beam angles in the axial and circumferential direction were not able to achieve greater than 90% code required volume as required by Code Case N-460. See Table 1 for additional information.

to 1CAN071202 Page 2 of 5 Radiography is not practical on these types of nozzle-to-vessel weld configurations, which prevent placement of the film and exposure source. To effectively perform any significant additional Code allowable ultrasonic examinations, modification and/or replacement of the component would be required. The examinations performed on the subject items in addition to the examination of other vessel welds contained in the Inservice Inspection program would detect generic degradation, if it existed, therefore demonstrating an acceptable level of integrity.

IV. PROPOSED ALTERNATIVE EXAMINATIONS No alternative testing is proposed at this time. Entergy has examined these welds to the extent practical and will continue to perform pressure testing on the subject components as required by the Code.

V. CONCLUSION 10 CFR 50.55a(g)(6)(i) states:

The Commission will evaluate determinations under paragraph (g)(5) of this section that 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.

Entergy believes that it is impractical to obtain greater examination coverage on these welds. To effectively obtain significant additional coverage would necessitate modification and/or replacement of the component. The examinations performed on the subject welds, in addition to the examination of similar welds contained in the program, would detect generic degradation, if it existed, demonstrating an acceptable level of integrity. Entergy requests the proposed relief be authorized pursuant to 10 CFR 50.55a(g)(6)(i).

to 1CAN071202 Page 3 of 5 Table 1 Limited B-D Examinations Component Description Additional Information Estimated %

Item Comp. Item Coverage of Exam Method Surface Exam Examination Summary Scan Plan Search Units Number ID Description Code Required and Limitations Examination Results Volume B3.110 05-012 Pressurizer 36.6 This is essentially a single sided exam See the attached Manual UT Wave modalities None Intermittent (PZR) Spray from the vessel surface due to the sketch (Figure 1) Effective are longitudinal and required. geometric Nozzle-to-Head component configuration. Both the derived from volumetric shear. indications at Circumferential nozzle and head are carbon steel with ultrasonic testing examination Insonification the nozzle Weld stainless steel cladding on the inside (UT) examination could only be angles included 0°, bore were surface. report 1-ISI-UT obtained from 45°, and 60°. observed 021 on file at ANO. the PZR head and surface. recorded.

B3.110 05-013 PZR Safety 42.0 This is essentially a single sided exam See the attached Manual UT Wave modalities None Intermittent Valve Nozzle-to- from the vessel surface due to the sketch (Figure 2) Effective are longitudinal and required. geometric Head component configuration. Both the derived from UT volumetric shear. indications at Circumferential nozzle and head are carbon steel with examination report examination Insonification the nozzle Weld stainless steel cladding on the inside 1-ISI-UT-10-022 on could only be angles included 0°, bore were surface. file at ANO. obtained from 45°, and 60°. observed the PZR head and surface. recorded.

to 1CAN071202 Page 4 of 5 Figure 1 Scan Plan and Coverage for Component 05-012 (Shaded area depicts code-required volume)

Not to Scale 0° 60° 45° Not Examined Weld to 1CAN071202 Page 5 of 5 Figure 2 Scan Plan and Coverage for Component 05-013 (Shaded area depicts code-required volume)

Not to Scale 0° 60° 45° Not Examined Weld

Attachment 2 to 1CAN071202 Request for Relief ANO1-ISI-022 to 1CAN071202 Page 1 of 7 REQUEST FOR RELIEF ANO1-ISI-022 Components / See Table 1 Numbers:

Code Classes: American Society of Mechanical Engineers (ASME) Code Class 1

References:

ASME Section XI 2001 Edition w/2003 Addenda, Table IWB-2500-1 Code Case N-716 Code Case N-460 Examination Category: B-J (R-A)

Item Number(s) B9.11 (R1.11; R1.11 / 16)

==

Description:==

Pressure Retaining Welds in Piping Unit / Inspection Arkansas Nuclear One, Unit 1 (ANO-1) / Fourth (4th) 10-Year Interval Applicability: Interval, First (1st) Inspection Period I. CODE REQUIREMENTS ASME Section XI, Table IWB-2500-1, Examination Category B-J, Pressure Retaining Welds in Piping - Inspection Program B:

Item B9.11, as allowed by the Risk Informed process, requires a volumetric examination of circumferential piping welds nominal pipe size 4 inches or larger, as depicted in Figures IWB-2500-8 and Risk Informed Inservice Inspection Evaluation Procedure, Electric Power Research Institute (EPRI) Report No. TR-106706.

ASME Code Case N-460 allows a reduction in Class 1 examination coverage due to interference or geometry, provided the reduction is less than 10%.

The examinations listed in Table 1 are Performance Demonstrated Initiative (PDI) examinations. With the implementation of Appendix VIII, only 1/2 Vee path examinations have been allowed to be used in austenitic materials and angle beams are no longer credited to extend beyond the centerline of austenitic welds for consideration of Code coverage, in accordance with qualified PDI procedures. Additional discussion, as to the examination coverage determination process when using Appendix VIII techniques on single-sided austenitic welds, is provided in Section III of this relief request.

II. RELIEF REQUEST Pursuant to 10CFR50.55a(g)(6)(i), Entergy Operations, Inc. (Entergy) requests relief from achieving greater than 90% coverage when performing volumetric examinations of the components identified in Table 1.

to 1CAN071202 Page 2 of 7 III. BASIS FOR RELIEF During ultrasonic examination of the piping welds listed in Table 1, greater than 90%

coverage of the required examination volume could not be obtained as required by Code Case N-460.

Access for axial scanning was limited on the upstream side of weld 22-064 at top dead center due to interference of a weld-o-let and on the downstream side of weld 22-064 at bottom dead center due to interference of an adjacent pipe run.

Access was limited to single side on weld 22-060 due to pipe-to-valve configuration for both axial and circumferential scans. See Table 1 for additional information.

Class 1 piping and components are often designed with welded joints such as nozzle-to-pipe, pipe-to-valve and pipe-to-pump which can physically obstruct a large portion of the required examination volume. For the weld 22-060, the examination was performed after the 10 CFR 50.55a mandatory implementation date for Appendix VIII of Section XI, and Code coverage percentages, provided, reflect what is currently allowed by qualified Appendix VIII techniques. Appendix VIII qualified PDI procedures have demonstrated that sound beams may potentially be attenuated and distorted when required to pass through austenitic weld metal. Still, the PDI qualified methods employ the best available technology for maximizing examination coverage of these types of welds. Examination was extended to the far side of the weld to the extent permitted by geometry, but this portion of the examination is not included in the reported coverage for welds examined under PDI and Appendix VIII rules.

Entergy has used the best available and EPRI approved techniques to examine the subject piping welds. To improve upon these examination coverage percentages, modification and/or replacement of the component would be required. Consistent with the ASME Section XI sampling approach, examination of the subject welds, when combined with examinations that have been performed on other welds within the same Examination Category, is adequate to detect generic degradation, if it existed, therefore demonstrating an acceptable level of integrity.

IV. PROPOSED ALTERNATIVE EXAMINATIONS No alternative testing is proposed at this time. Entergy has examined the subject welds to the extent practical and will continue to perform pressure testing and VT-2 visual examination in accordance with ASME Section XI requirements to compliment the limited examination coverage after each refueling outage.

to 1CAN071202 Page 3 of 7 V. CONCLUSION 10 CFR 50.55a(g)(6)(i) states:

The Commission will evaluate determinations under paragraph (g)(5) of this section that 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.

Entergy believes that it is impractical to obtain greater examination coverage on these areas. To obtain additional coverage would necessitate modification and/or replacement of the component. The examinations performed on the subject areas, in addition to the examination of similar welds contained in the program would detect generic degradation, if it existed, demonstrating an acceptable level of integrity. Therefore, Entergy requests the proposed relief be authorized pursuant to 10 CFR 50.55a(g)(6)(i).

to 1CAN071202 Page 4 of 7 Table 1 Limited B-J (R-A) Examinations Component Description Additional Information Estimated %

Item Comp. Item Exam Method Surface Exam Coverage of Code Examination Summary Scan Plan Search Units Number ID Description and Limitations Examination Results Required Volume B9.11 22-064 Pipe-to-Elbow Axial - 83.8 Component was scanned from See the attached Manual UT Wave modality was None Intermittent (R1.11) Circumferential Circumferential - both sides; however scanning of sketch (Figure 1) See the detailed shear. required. root Weld 91.9 the required code volume was derived from sketch (Figure 2) Insonification geometry limited in the axial direction from ultrasonic testing of the limitations angles included observed Cumulative - the upstream side due to a weld-o- (UT) examination and recorded 87.8 and their 45°, 60°, and 70°.

let and in both the axial and report 1-ISI-UT proximity to the 360° on the circumferential direction on the 019 on file at ANO. component. down-stream downstream side by an adjacent side.

run of piping B9.11 22-060 Pipe-to-Valve Axial - 50 This is essentially a single sided See the attached Manual UT Wave modality was None Intermittent (R1.11 / Circumferential Circumferential - examination from the stainless sketch (Figure 3) A detailed sketch shear. required. root

16) Weld 50 steel piping side due to the derived from UT (Figure 3) of the Insonification geometry component configuration. Axial examination report limitation is angles included observed Cumulative - 50 and circumferential scanning was 1-ISI-UT-10-018 on and recorded included with the 45°, 60°, and 70°.

performed from the valve side to file at ANO. scan plan. 360° on the the extent possible. No code down-stream credit is being claimed for these side.

scans.

to 1CAN071202 Page 5 of 7 Figure 1 Scan Plan and Coverage for Component 22-064 Not to Scale CL 60° 60° 60° PIPE 60° ELBOW B C D E F G H I A

FLOW to 1CAN071202 Page 6 of 7 Figure 2 Limitation for Component 22-064 Not to Scale

.7 22-064 1.5 TOP VIEW 22-064 SIDE VIEW 22-065 1.5 LENGTH OF WELD OBSTRUCTED ON ELBOW SIDE to 1CAN071202 Page 7 of 7 Figure 3 Scan Plan and Coverage for Component 22-060 Not to Scale VALVE PIPE CL 2.25 MHz 60° 60° 70° A B C D E F FLOW