1CAN082201, Request for Relief from American Society of Mechanical Engineers Section XI Volumetric Examination Requirements - Fifth 10-Year Interval, First Period
| ML22236A500 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 08/24/2022 |
| From: | Couture P Entergy Operations |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 1CAN082201 | |
| Download: ML22236A500 (22) | |
Text
Entergy Operations, Inc., 1340 Echelon Parkway, Jackson, MS 39213 1CAN082201 10 CFR 50.55a August 24, 2022 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555
SUBJECT:
Request for Relief from American Society of Mechanical EngineersSection XI Volumetric Examination Requirements -
Fifth 10-Year Interval, First Period Arkansas Nuclear One, Unit 1 NRC Docket No. 50-313 Renewed Facility Operating License No. DPR-51 During the first inspection period of the Fifth 10-Year Inservice Inspection interval at Entergy Operations', Inc. (Entergy) Arkansas Nuclear One, Unit 1 (ANO-1) the components identified in the enclosure received less than the required volumetric examination coverage. In accordance with 10 CFR 50.55a(g)(5)(iii), Entergy requests relief from the requirements of American Society of Mechanical Engineers (ASME), Boiler and Pressure Vessel Code,Section XI because the required examination coverage was impractical due to the geometric configuration and material type of the components.
This request is for the fifth ANO-1 10-year Inservice Inspection interval, first period. The interval started on May 31, 2017. The first inspection period ended May 30, 2021. The relief request is provided in the enclosure.
There are no new regulatory commitments made in this submittal.
If there are any questions or if additional information is needed, please contact Riley Keele, Manager, Regulatory Assurance, Arkansas Nuclear One, at 479-858-7826.
Respectfully, Phil Couture PC/rwc
Enclosure:
Request for Relief - ANO1-ISI-036 Phil Couture Senior Manager Fleet Regulatory Assurance - Licensing Tel 601-368-5102 Philip Couture Digitally signed by Philip Couture Date: 2022.08.24 07:49:19
-05'00'
1CAN082201 Page 2 of 2 cc:
NRC Region IV Regional Administrator NRC Senior Resident Inspector - Arkansas Nuclear One NRC Project Manager - Arkansas Nuclear One
Enclosure 1CAN082201 Request for Relief - ANO1-ISI-036
Enclosure 1CAN082201 Page 1 of 19 REQUEST FOR RELIEF ANO1-ISI-036 Components /
Numbers:
See Table 1 Below Code Classes:
American Society of Mechanical Engineers (ASME) Code Class 1
References:
ASME Code Case N-716-1 Examination Category: R-A Item Number(s)
R1.11, R1.11/16, R1.20
==
Description:==
High Safety Significant Class 1 and 2 Piping Welds Unit / Inspection Interval Applicability:
Arkansas Nuclear One, Unit 1 (ANO-1) / Fifth (5th) 10-Year Interval, First Period I.
CODE REQUIREMENTS ASME Section XI, Code Case N-716-1, Examination Category R-A, "Risk Informed Piping Welds":
- 1)
Item R1.11 requires volumetric examination of elements subject to thermal fatigue as depicted in Figure IWB-2500-8(c) and IWB-2500-9, 10, 11.
- 2)
Item R1.11/16 requires volumetric examination of elements subject to Thermal Fatigue and subject to Intergranular or Transgranular Stress Corrosion Cracking as depicted in Figure IWB-2500-8(c) and IWB-2500-9, 10, 11.
- 3)
Item R1.20 requires volumetric examination of elements not subject to a Degradation Mechanism as depicted in Figure IWB-2500-8(c) and IWB-2500-9, 10, 11.
II.
RELIEF REQUEST In accordance with 10 CFR 50.55a(g)(5)(iii), Entergy Operations, Inc. (Entergy) requests relief from achieving the Code-required coverage when performing volumetric examinations of the components identified in Table 1.
Enclosure 1CAN082201 Page 2 of 19 III.
BASIS FOR RELIEF During ultrasonic examination of the ASME Section XI, Appendix VIII piping welds listed in Table 1, greater than 90% coverage of the required examination volume could not be obtained. Examinations were performed utilizing EPRI qualified Appendix VIII, Supplement 2 procedures specific to wrought austenitic piping welds.
Due to the geometric configuration and material type of the components, effective volumetric examination could only be performed as noted in the Table 1 for each weld. Although insonification was extended to the far side of the welds to the extent practical, this portion of the examination is not included in the reported examination coverage per the Performance Demonstration Initiative (PDI) and ASME Section XI, Appendix VIII rules. The use of 45, 60° and 70 beam angles in the axial and circumferential direction were not able to achieve greater than 90% code required volume. See Table 1 for specific information.
Entergy has used the best available and EPRI approved techniques to examine the subject piping welds. 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 piping welds contained in the Inservice Inspection (ISI) program would detect generic degradation, if it existed, therefore demonstrating an acceptable level of integrity.
ANO 1 has initiated a Risk-Informed ISI program for the 5th 10-Year Interval in accordance with ASME Code Case N-716-1, as approved in Regulatory Guide 1.147, Inservice Inspection Code Case Acceptability, ASME Section XI, Division 1, Revision 19 and listed in Table 1, Acceptable Section XI Code Cases.
ASME Code Case N-716-1, Table 1 Note 3 requires when the required examination volume or area cannot be examined due to interference by another component or part geometry, limited examinations shall be evaluated for acceptability. Acceptance of limited examinations or volumes shall not invalidate the results of the change-in-risk evaluation.
The following is a summary of the cumulative effect of the limited examinations for each system and total being reported in the relief request.
The six welds are contained in two systems. Four welds in Decay Heat Removal (DH) and two welds in Makeup and Purification (MU).
Decay Heat Removal (DH) (Welds19-006, 19-038,36-028, and 36-056)
These four DH R1.20 welds are not credited towards the inspection requirements of ASME Code Case N-716-1 and do not have a contribution to this adjusted delta risk evaluation. These examinations were performed as preservice requirement for high safety significant components. The below table provides the delta risk with the four welds credited and with the four welds not credited. The columns under heading
Enclosure 1CAN082201 Page 3 of 19 "Examined" include the delta risk with the four welds included. The columns under heading "Not Examined" include the adjusted delta risk after removing the four welds.
As can be seen, there is no change to the result, and this result is below the individual system acceptable limits of 1E-07 for Core Damage Frequency (CDF) and 1E-08 for Large Early Release Frequency (LERF). Therefore, a limited examination of the four DH welds is acceptable.
Decay Heat Removal (DH)
CDF Impact LERF Impact Source of Delta Risk w/
Probability of Detection (POD) w/o POD w/ POD w/o POD Examined
-3.75E-09 7.83E-09
-7.72E-10 1.54E-09 5th interval periodic update required by N-716 Not Examined
-3.75E-09 7.83E-09
-7.72E-10 1.54E-09 Adjusted delta risk using the periodic update delta risk Makeup and Purification (MU) (Welds22-060 and 22-064)
To quantify the effect on delta risk for the two MU welds, the delta risk is adjusted by not crediting the two MU welds with limited examination coverage. The below table provides the delta risk with the two MU welds credited and with the two MU welds not credited.
The columns under heading "Examined" include the delta risk with the two welds included. The columns under heading "Not Examined" include the adjusted delta risk after removing the two welds. As can be seen, the change is negligible and well below the individual system acceptable limits of 1E-07 for CDF and 1E-08 for LERF.
Therefore, a limited examination of the two MU welds is acceptable.
Makeup and Purification (MU)
CDF Impact LERF Impact Source of Delta Risk w/ POD w/o POD w/ POD w/o POD Examined
-5.93E-08 2.93E-09
-1.25E-08
-3.90E-11 5th interval periodic update required by N-716 Not Examined
-5.28E-08 6.56E-09
-1.12E-08 6.87E-10 Adjusted delta risk using the periodic update delta risk Cumulative Effect to Delta Risk for All Six Welds In the initial request for alternative to use a risk informed program for the fifth interval, the delta risk was provided for each system and cumulatively for all systems. The impact of the limited examination on the delta risk for the individual system is addressed above. The cumulative effect on the total delta risk is provided below. The columns under heading "Examined" are the delta risk with the six welds included. The columns under heading "Not Examined" is the adjusted delta risk after removing the six welds. As
Enclosure 1CAN082201 Page 4 of 19 can be seen, the change is negligible and well below the total increase acceptable limits of 1E-06 for CDF and 1E-07 for LERF. Therefore, a limited examination of the four DH and two MU welds is acceptable.
Total CDF Impact CDF Impact CDF Impact w/ POD w/ POD w/ POD w/ POD w/ POD Examined
-9.86E-08
-9.86E-08
-9.86E-08
-9.86E-08
-9.86E-08 Not Examined
-9.21E-08
-9.21E-08
-9.21E-08
-9.21E-08
-9.21E-08 IV.
PROPOSED ALTERNATIVE EXAMINATIONS No alternative testing is proposed at this time. Entergy has examined the subject items to the extent practical and will continue to perform pressure testing on the subject areas as required by the Code.
V.
CONCLUSION In accordance with 10 CFR 50.55a(g)(5)(iii), relief is requested from the examination coverage requirements of the subject welds due to the geometric configuration and material type of the components.
Entergy has determined 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 in accordance with 10 CFR 10.55a(g)(6)(i) Impractical ISI requirements.
Enclosure 1CAN082201 Page 5 of 19 Table 1 Limited R-A Examinations Component Description Additional Information Item Number Comp.
ID Item Description Estimated %
Coverage of Code Required Volume Examination Summary Scan Plan Exam Method and Limitations Search Units Surface Examination Exam Results R1.20 19-006 Valve to Pipe Circumferential Weld 50 This is a single sided exam.
Examination of the required volume as depicted in Figure IWC-2500-8(c) with Note 1 from ASME Code Case N-716-1 was limited due to the component configuration. Both the Valve and Pipe are stainless steel.
See the attached information (Figures 1) derived from PSI Baseline Ultrasonic Testing (UT) examination performed in 1R27 and report 1-BOP-UT-18-014 on file at ANO.
Manual UT.
Scan path limitation due to the configuration of the component.
Wave modalities are shear and longitudinal.
Insonification angles included 0°, 45°, 60°S and 60°RL.
Search unit frequencies were 4.0 MHz for 0°,
2.25 MHz for 45°,
60°S and 2.0 MHz for 60°RL.
None required One geometry indication was observed and recorded with the 45° at low amplitude from 13.75 to 19.5 from TDC.
Acceptable R1.20 19-038 Valve to Elbow Circumferential Weld 48 This is a single sided examination.
Examination of the required volume as depicted in Figure IWC-2500-8(c) with Note 1 from ASME Code Case N-716-1 was limited due to the component configuration. Both the Valve and Elbow are stainless steel.
See the attached information (Figures 2) derived from PSI Baseline UT examination performed in 1R27 and report 1-BOP-UT-18-016 on file at ANO.
Manual UT.
Scan path limitation due to the configuration of the component.
Wave modalities are shear and longitudinal.
Insonification angles included 0°, 45°, 60°S, 60°RL and 70°.
Search unit frequencies were 4.0 MHz for 0°,
2.25 MHz for 45°,
60°S, 70° and 2.0 MHz for 60°RL angle.
None required 360° Intermittent geometry indications were observed and recorded with 45°on near side and 60° on far side of weld.
Acceptable
Enclosure 1CAN082201 Page 6 of 19 Table 1 Limited R-A Examinations Component Description Additional Information Item Number Comp.
ID Item Description Estimated %
Coverage of Code Required Volume Examination Summary Scan Plan Exam Method and Limitations Search Units Surface Examination Exam Results R1.11/16 22-060 Pipe to Valve Circumferential Weld 50 This is a single sided examination.
Examination of the required volume as depicted in Figure IWC-2500-8(c) with Note 1 from ASME Code Case N-716-1 was limited due to the component configuration. Both the Pipe and Valve are stainless steel.
See the attached information (Figures 3) derived from ISI UT examination performed in 1R28 and report 1-ISI-UT-19-017 on file at ANO.
Manual UT.
Scan path limitation due to the configuration of the component.
Wave modalities are shear.
Insonification angles included 45°, 60° and 70°.
Search unit frequencies were 2.25 MHz all angles.
None required 360° Intermittent geometry indication was observed and recorded with 60° on downstream side of weld.
Acceptable R1.11 22-064 Pipe to Elbow Circumferential Weld 87.4 This is a dual sided exam.
Examination of the required volume as depicted in Fig. IWC-2500-8(c) with Note 1 from ASME Code Case N-716-1 was limited due to the component configuration. Both the Pipe and Elbow are stainless steel.
See the attached information (Figures 4) derived from ISI UT examination performed in 1R28 and report 1-ISI-UT-19-019 on file at ANO.
Manual UT.
Scan path limitation due to the configuration of the component.
Wave modalities are shear.
Insonification angles included 45°, 60° and 70°.
Search unit frequencies were 5.0 MHz for 45° and 60° and 2.25 MHz for 70° angles.
None required 360° Intermittent geometry indication was observed and recorded with 60° on downstream side of weld.
Acceptable
Enclosure 1CAN082201 Page 7 of 19 Table 1 Limited R-A Examinations Component Description Additional Information Item Number Comp.
ID Item Description Estimated %
Coverage of Code Required Volume Examination Summary Scan Plan Exam Method and Limitations Search Units Surface Examination Exam Results R1.20 36-028 Elbow to Valve Circumferential Weld 50 This is a single sided exam.
Examination of the required volume as depicted in Fig. IWC-2500-8(c) with Note 1 from ASME Code Case N-716-1 was limited due to the component configuration. Both the Elbow and Valve are stainless steel.
See the attached information (Figures 5) derived from PSI Baseline UT examination performed in 1R27 and report 1-BOP-UT-18-013 on file at ANO.
Manual UT.
Scan path limitation due to the configuration of the component.
Wave modalities are shear and longitudinal.
Insonification angles included 0°, 45°, 60°S and 60°RL.
Search unit frequencies were 4.0 MHz for 0°,
2.25 MHz for 45°,
60°S and 2.0 MHz for 60°RL.
None required No indications were observed or recorded.
Acceptable R1.20 36-056 Pipe to Valve Circumferential Weld 50 This is a single sided exam.
Examination of the required volume as depicted in Fig. IWC-2500-8(c) with Note 1 from ASME Code Case N-716-1 was limited due to the component configuration. Both the Pipe and Valve are stainless steel.
See the attached information (Figures 6) derived from PSI Baseline UT examination performed in 1R27 and report 1-BOP-UT-18-015 on file at ANO.
Manual UT.
Scan path limitation due to the configuration of the component.
Wave modalities are shear and longitudinal.
Insonification angles included 0°, 45°, 60°S and 60°RL.
Search unit frequencies were 4.0 MHz for 0°,
2.25 MHz for 45°,
60°S and 2.0 MHz for 60°RL.
None required No indications were observed or recorded.
Acceptable
Enclosure 1CAN082201 Page 8 of 19 Figure 1a Scan Plan and Coverage for ISI Component 19-006 Not to Scale 19-006
Enclosure 1CAN082201 Page 9 of 19 Figure 1b Location Sketch for ISI Component 19-006 Not to Scale
Enclosure 1CAN082201 Page 10 of 19 Figure 2a Scan Plan and Coverage for ISI Component 19-038 Not to Scale 19-038 is additionally limited at BDC due to drain.
Enclosure 1CAN082201 Page 11 of 19 Figure 2b Location Sketch for ISI Component 19-038 Not to Scale
Enclosure 1CAN082201 Page 12 of 19 Figure 3a Scan Plan and Coverage for ISI Component 22-060 Not to Scale 22-060
Enclosure 1CAN082201 Page 13 of 19 Figure 3b Location Sketch for ISI Component 22-060 Not to Scale
Enclosure 1CAN082201 Page 14 of 19 Figure 4a Scan Plan and Coverage for ISI Component 22-064 Not to Scale 22-064
Enclosure 1CAN082201 Page 15 of 19 Figure 4b Location Sketch for ISI Component 22-064 Not to Scale
Enclosure 1CAN082201 Page 16 of 19 Figure 5a Scan Plan and Coverage for ISI Component 36-028 Not to Scale 36-028
Enclosure 1CAN082201 Page 17 of 19 Figure 5b Location Sketch for ISI Component 36-028 Not to Scale
Enclosure 1CAN082201 Page 18 of 19 Figure 6a Scan Plan and Coverage for ISI Component 36-056 Not to Scale
Enclosure 1CAN082201 Page 19 of 19 Figure 6b Location Sketch for ISI Component 36-056 Not to Scale