LG-24-089, Owners Activity Report (OAR-1) for Li1R20
| ML24206A251 | |
| Person / Time | |
|---|---|
| Site: | Limerick  |
| Issue date: | 07/24/2024 |
| From: | Gillin M Constellation Energy Generation |
| To: | NRC Region 1, Document Control Desk, Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML24206A250 | List: |
| References | |
| LG-24-089 | |
| Download: ML24206A251 (1) | |
Text
Constellation ASME Section XI LG-24-089 July 24, 2024 USNRC Region I, Regional Administrator U.S. Nuclear Regulatory Commission, Region I 475 Allendale Road, Suite 102 King of Prussia, PA 19406-1415 Limerick Generating Station, Unit 1 Renewed Facility Operating License Nos. NPF-39 NRC Docket Nos. 50-352
Subject:
Limerick Generating Station Unit 1 Owner's Activity Report (OAR-1) for Li1 R20 The Limerick Generating Station Unit 1 OAR-1 for Li1 R20 is submitted in accordance with ASME Section XI, Article IWA-6200 and ASME Section XI Code Case N-532-5. This report includes inspections and repair and replacement activities completed during the third Period of the Fourth lnservice Inspection Interval and the Third Containment lnservice Inspection Interval.
During refueling outage Li1 R20, automated phased array ultrasonic examination of reactor recirculation inlet nozzle N2H to safe-end weld identified two circumferentially oriented flaws indicative of lntergranular Stress Corrosion Cracking (IGSCC). These flaws have been previously identified and evaluated as acceptable. The Li1 R20 flaw sizing remains unchanged from previous examinations. The IWB-3600 analytical evaluation was revised to satisfy a Limerick License Renewal Commitment and is being provided (Attachment 2) as required by IWB-3134.
During Li1 R20, visual examinations of the submerged suppression pool liner were performed as required by ASME Section XI, Limerick License Renewal Commitments, and the Limerick coating maintenance program. These visual examinations identified a condition in the accessible area that could lead to degradation of an inaccessible area. An evaluation was performed for continued acceptance and is being provided (Attachment 3) as required by 10 CFR 50.55a(b)(2)(ix)(A)(2).
There are no regulatory commitments contained in this letter.
If you have any questions or require additional information, please contact Marcellus Ruff at 610-718-3530.
Respectfully, Michael F. Gillin Site Vice President, Limerick Generating Station Constellation Energy Generation, LLC
Attachments:
- 1. OAR-1 Owner's Activity Report for Limerick Generating Station
- 2. EC 641252, Rev. 1, Evaluation of Unit 1 FIG 07-01 N2H Flaw Identified in IR 04766062
- 3. EC 641238, Rev. 0, 1R20 Evaluation of Degraded Leak Chase Channel and Suppression Pool Liner Plate Bulges
LG-24-089 Attachment 1 Page 1 of 3 Attachment OAR-1 Owners Activity Report for Limerick Generating Station FORM OAR-1 OWNERS ACTIVITY REPORT Report Number Li1R20 Plant Limerick Generating Station, 3146 Sanatoga Road, Pottstown, Pennsylvania 19464 Unit No.
1 Commercial Service Date February 1, 1986 Refueling Outage Number Li1R20 (if applicable)
Current Inspection Interval Fourth Inspection Interval (ISI) & Third Inspection Interval (Containment ISI)
(1st, 2nd, 3rd, 4th, other)
Current Inspection Period Third Inspection Period (ISI and Containment ISI)
(1st, 2nd, 3rd )
Edition and Addenda of Section XI applicable to the Inspection Plans ASME Section XI 2007 Ed. through 2008 Add. (4th ISI/3rd CISI Interval)
Date and Revision of Inspection Plans ISI Program Plan (ER-LG-330-1001), Rev. 21 (1/13/2022), Rev. 22 (4/3/2023),
Rev. 23 (2/15/2024)
Edition and Addenda of Section XI applicable to repair/replacement activities, if different than the inspection plans Same as above Code Cases used:
N-508-4, N-532-5, N-552-1, N-613-2, N-639, N-702, N-716-2, N-747, N-805, N-854, N-864 CERTIFICATE OF CONFORMANCE I certify that (a) the statements made in this report are correct; (b) the examinations and tests, meet the Inspection Plan as required by the ASME Code,Section XI; and (c) the repair/replacement activities and evaluations supporting the completion of Li1R20 conform to the requirements of Section XI.
(refueling outage number)
Signed, Fleet ISI Program Owner Date (Owner or Owners designee, Title)
CERTIFICATE OF INSERVICE INSPECTION I, the undersigned, holding a valid commission issued by the National Board of Boiler and Pressure Vessel Inspectors and employed by The Hartford Steam Boiler Inspection and Insurance Company of Hartford, Connecticut have inspected the items described in this Owner's Activity Report, and state that, to the best of my knowledge and belief, the Owner has performed all activities represented by this report in accordance with the requirements of Section XI.
By signing this certificate neither the Inspector nor his employer makes any warranty, expressed or implied concerning the repair/replacement activities and evaluation described in this report. Furthermore, neither the Inspector nor his employer shall be liable in any manner for any personal injury or property damage or a loss of any kind arising from or connected with this inspection.
Commissions 14396 R, N, I, C (Inspectors Signature)
(National Board Number and Endorsement)
Date
- Weis, Mark E.
Digitally signed by Weis, Mark E.
Date: 2024.07.11 15:57:14 -04'00' JORDAN S. KAN Digitally signed by JORDAN S. KAN Date: 2024.07.12 12:14:06 -04'00'
LG-24-089 Attachment 1 Page 2 of 3 Attachment OAR-1 Owners Activity Report for Limerick Generating Station TABLE 1 ITEMS WITH FLAWS OR RELEVANT CONDITIONS THAT REQUIRED EVALUATION FOR CONTINUED SERVICE Examination Category Examination Item Number Item Description Evaluation Description AUG 01,07 VRR-1RD-1A N2H, recirc inlet nozzle N2H to safe-end dissimilar metal weld.
(IGSCC Category E)
Automated phased array ultrasonic examination of reactor recirc inlet nozzle N2H to safe-end dissimilar metal weld (VRR-1RD-1A N2H) identified two circumferentially oriented flaws indicative of IGSCC. Both flaws were previously identified and accepted by IWB-3600 analytical evaluation SMC ODonnel Fracture Mechanics Report dated 9/7/1990. The Li1R20 sizing remains unchanged from previous examinations. The IWB-3600 analytical evaluation has been revised to satisfy a Limerick License Renewal Commitment. EC 641252, Rev. 1 continues to demonstrate that both flaws are acceptable until the next required examination which will be performed no later than Li1R23 (2030). EC 641252, Rev.
1 is included as an attachment to the Li1R20 OAR-1 as required by IWB-3134.
E-A E1.11 Suppression Pool Liner and Leak Chase Channel During visual examinations of the suppression pool submerged space (E-A, E1.11), a small hole was identified in the leak chase channel allowing water to enter the inaccessible area.
An evaluation was performed (EC 641238, Rev.
- 0) and determined the condition is acceptable until the next required examination in Li1R22 (2028). EC 641238, Rev. 0 is included as an attachment to the Li1R20 OAR-1 as required by 10 CFR 50.55a(b)(2)(ix)(A)(2).
F-A F1.10C DCA-104-H003, variable spring support VT-3 examination of variable support DCA-104-H003 identified that the cold load setting was out of tolerance. The as found condition was evaluated (EC 641254) and it was determined the support can perform the intended design function in the as found condition. The station elected to rework the support during Li1R20 to restore the design cold load setting.
LG-24-089 Attachment 1 Page 3 of 3 Attachment OAR-1 Owners Activity Report for Limerick Generating Station TABLE 2 ABSTRACT OF REPAIR/REPLACEMENT ACTIVITIES REQUIRED FOR CONTINUED SERVICE Code Class Item Description Description Of Work Date Completed Repair/Replacement Plan Number None None None None None
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EC EVAL 0000641252, Rev. 1 Page 1 of 4 This Engineering Technical Evaluation was prepared in accordance with CC-AA-309-101 Rev. 16. An HU-AA-1212 Rev. 13 Risk Ranking was performed. All consequence risk factors screened as Low Consequence making it Risk Rank 1. Therefore, no further review of risk is necessary and the controls and reviews of CC-AA-309-101, Engineering Technical Evaluations, are adequate without additional compensatory measures or augmented reviews. This evaluation will require an independent review as it affects safety related components.
Document Number: EC 0000641252, Rev. 1
Title:
EVALUATION OF UNIT 1 FIG 07-01 N2H FLAW IDENTIFIED IN IR 04766062 Reason for evaluation/scope:
Per IR 04766062, during 1R20 NDE technicians performed an automated phased-array ultrasonic testing (PAUT) examination of component VRR-1RD-1A N2H (N2H nozzle to safe end dissimilar metal weld) per work order 5367852 for the Inservice Inspection (ISI) program. VRR-1RD-1A N2H is the 14.25 inch diameter weld that connects the low alloy steel N2 nozzle forging to the SA 182 F316L N2 safe end forging as shown on drawing XI-BF-002 (Reference 5), which is the H recirculation inlet nozzle.
The automated PAUT examination revealed two indications per Customer Notification Form, CNF ISI-002 (Attachment 2). Both identified indications were previously identified, refer to WO 4942077 for previous Li1R18 inspection. Indication #1 was found with a length of 5.12 inches and a through wall depth of 0.34 inches and is located approximately 3.7 inches clockwise from top dead center, in the weld material during Li1R20. Indication #2 has a length of 4.65 inches and a through wall depth of 0.30 inches and is located approximately 32.6 inches clockwise from the top dead center, in the weld material during Li1R20. Both indications were identified in the new weld material as seen in Detail A of drawing XI-BF-002 (Reference 5). Both indications are inner diameter (ID) connected intergranular stress corrosion cracking (IGSCC) flaws which have been previously accepted by analytical evaluation in accordance with ASME Section XI (Reference 4), IWB-3600. These flaws are considered unchanged from previous examination in Li1R18 (2020) with any changes in dimension being within the error band of the inspection procedure.
This Engineering Technical Evaluation is written to evaluate the N2H weld for continued service.
The revision 1 scope of this technical evaluation, as requested by assignment 04766062-02, is to document acceptance of VRR-1RD-1A N2H indications using Structural Integrity flaw growth analysis until the next required examination which is six (6) years. The evaluation shall be performed in accordance with ASME Section XI, IWB-3600 for a 6 year inspection cycle over 60 years per License Renewal Assignment 1232104-04-02. This is a License Renewal Commitment.
EC EVAL 0000641252, Rev. 1 Page 2 of 4 Detailed evaluation:
The VRR-1RD-1A N2H nozzle to safe end weld has been identified at LGS with two subsurface flaws connected to the inside surface of the pipe, which required evaluation in accordance with ASME Code, section IWB-3600. The indications in Li1R18 showed no change compared to the indications identified in Li1R15 (2014). The indications were reported as bounded by the SMC ODonnell Fracture Mechanics Report, dated 09/07/1990 (Reference 6) in Li1R15, and therefore were acceptable for continued service as found in Li1R18 through at least Li1R21.
The two UT indications were initially identified in 1R02 (1989) and 1R07 (1998) within the VRR-1RD-1A N2H nozzle to safe end weld material. This welds susceptibility to IGSCC was mitigated by Mechanical Stress Improvement Process (MSIP) in 1R04 (1992). Post MSIP weld UT was performed for each of the next four refueling outages starting with 1R05 and ending with 1R08. Following 1R08 the weld was upgraded from GL 88-01 Category F to Category E, and the weld could be examined in accordance with the Category E exam schedule provided that there were no adverse changes in the UT indication.
The SMC ODonnell Fracture Mechanics Report performed a linear elastic fracture mechanics analysis for the observed indication to compute the crack propagation with and without MSIP mitigation-based crack growth rates. It was found that for a crack starting at a depth of 70% through wall, it would not penetrate through the wall within the next three fuel cycles under MSIP stress values, and that circumferential cracks less than 50% through wall would be arrested by MSIP.
In 2024, prior to Li1R20, Structural Integrity Associates (SIA) was contracted to perform a bounding flaw evaluation for the recirculation inlet N2 nozzle to safe end weld material for an operating period of 24 months beyond the ultrasonic testing (UT) characterization and sizing. The analysis is included as Attachment 1 to this EC.
This technical evaluation will compare the circumferentially oriented, ID-connected, IGSCC flaws identified in issue report (IR) 04766062 to the flaw evaluation performed by SIA in Attachment 1 to show how the flaw is bounded.
- During Li1R20, GEH performed an automated UT examination of the N2H nozzle to safe end dissimilar metal weld (VRR-1RD-1A N2H) in accordance with WO 05367852. The examination recorded two previously identified indications as provided in GEH customer notification form (CNF) CNF-ISI-002 (Attachment 2).
- Indication #1 has a length of 5.12 inches and an ID connected depth of 0.34 inches. It is located approximately 3.7 clockwise from top dead center in the weld material.
- Indication #2 has a length of 4.65 inches and an ID connected depth of 0.30 inches. It is located approximately 32.6 clockwise from top dead center in the weld material.
EC EVAL 0000641252, Rev. 1 Page 3 of 4
- The total clockwise length of the N2H nozzle is 44.77 inches based on a nozzle OD of 14.25 inches.
- For multiple flaws to not be considered a single flaw, the distance between adjacent flaws shall be greater than dimension S as determined by Figure IWA-3330-1 from ASME Section XI, IWA-3330. Required distance between flaws shall be at least 0.17 inches (0.34/2) away. The indications have separation greater than 0.185 inches; therefore, they can be evaluated as separate flaws and do not need to be combined.
SIA Report (2301474.301P), LGS Bounding Flaw Evaluation of the N2 and N17 Nozzle-to-Safe End Welds NDE Indications Tables 4 and 5 provides the bounding circumferential flaw size for the N2 nozzle dissimilar metal weld for a 24 month operating period. Both indications #1 and #2 are bounded by a flaw depth of 0.40 inches with depths of 0.34 inches and 0.30 inches, respectively. A bounding flaw depth of 0.40 allows a bounding flaw length of 17.72 inches. Indication #1 has a flaw length of 5.12 inches and indication #2 has a flaw length of 4.65 inches which are less than the bounding flaw length of 17.72 inches. Therefore, both indications are bounded by the SIA Report in Attachment 1 for a flaw depth of 0.40 inches with a flaw length of 17.72 inches.
In summary, the circumferentially oriented, ID-connected, IGSCC flaws identified in IR 04766062 are bounded by the SIA flaw evaluated in Attachment 1. The flaws are acceptable for an operating period of 24 months beyond the ultrasonic testing (UT) characterization and sizing.
Assignment 04766062-06 was generated to Programs to obtain a refined SIA fracture mechanics evaluation to increase the inspection interval or schedule an inspection within 24 months from 1R20 for the N2H nozzle to safe-end weld.
The refined SIA fracture mechanics evaluation - SIA Report (2301474.303P), LGS Bounding Flaw Evaluation of the N2 and N17 Nozzle-to-Safe Ends Welds NDE Indications (Attachment 3) - has been completed. Based on historical UT exams, the flaw dimensions of IND #1 and IND #2 have fluctuated up to 5.20 length and 0.35 depth. These bounding dimensions were used as the initial flaw size for the fracture mechanics evaluation. Based on these bounding initial flaw dimensions, Table 4 shows that the time required for the initial flaw to reach the maximum allowable flaw depth is 86 months which is greater than the 72 month or 6 year inspection interval.
Conclusions/findings:
The circumferentially oriented, ID-connected, IGSCC flaws identified in IR 04766062 are bounded by the SIA flaw evaluation in Attachment 1. The flaws found are acceptable for continued service based on the requirements of ASME Code,Section XI. The flaws are acceptable for an operating period of 24 months beyond the ultrasonic testing (UT) characterization and sizing. Assignment 04766062-06 was generated to Programs to obtain a refined SIA fracture mechanics evaluation to increase the inspection interval or
EC EVAL 0000641252, Rev. 1 Page 4 of 4 schedule an inspection within 24 months from 1R20 for the N2H nozzle to safe-end weld.
Note that the SIA fracture mechanics evaluation in Attachment 1 was performed generically for all N2 nozzles at Limerick. This evaluation can be used in the future to accept the flaws; however, it is incumbent upon the user of the evaluation to ensure the inputs in the report bound the nozzle being assessed.
The previously mentioned refined SIA fracture mechanics evaluation has been completed. The refined evaluation considered a flaw with initial length of 5.20 and initial depth of 0.35, which bounds the dimensions of both flaws reported in CNF ISI-002. The refined evaluation concludes that the reported flaws are acceptable for continued service, based on the requirements of ASME Code,Section XI, Section IWB-3600 for an operating period of 72 months over 60 years of plant life beyond the UT characterization and sizing.
References:
=
- 1. Issue Report 04766062, Dated 04/13/2024
- 2. CC-AA-309-101, Revision 16
- 3. HU-AA-1212, Revision 13
- 4. ASME Section XI, 2007 Edition with 2008 Addenda
- 5. XI-BF-002, Revision 0
- 6. SMC ODonnell Fracture Mechanics Report, dated 09/07/1990 Attachments:
========== - SIA Fracture Mechanics Evaluation for N2 Nozzle to Safe End Welds (File No. 2301474.301P) - CNF-ISI-002 Flaw Examination Results - SIA Refined Fracture Mechanics Evaluation for N2 Nozzle to Safe End Welds (File No. 2301474.303P)
See Asset Suite 9 milestones for preparer, reviewer, and approver.
to EC 641252, Rev. 0 Page 1 of 6 to EC 641252, Rev. 0 Page 2 of 6 to EC 641252, Rev. 0 Page 3 of 6 to EC 641252, Rev. 0 Page 4 of 6 to EC 641252, Rev. 0 Page 5 of 6 to EC 641252, Rev. 0 Page 6 of 6