NLS2021058, Response to Nuclear Regulatory Commissions Request for Additional Information for Alternative Request RS-01
| ML21285A286 | |
| Person / Time | |
|---|---|
| Site: | Cooper  |
| Issue date: | 10/12/2021 |
| From: | Dent J Nebraska Public Power District (NPPD) |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| NLS2021058 | |
| Download: ML21285A286 (18) | |
Text
H Nebraska Public Power District NLS2021058 October 12, 2021 U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555-0001
Always there when you need us" 10 CFR 50.55a
Subject:
Response to Nuclear Regulatory Commission's Request for Additional Information for Alternative Request RS-01 Cooper Nuclear Station, Docket No. 50-298, DPR-46
References:
- 1.
Email from Thomas Wengert, U.S. Nuclear Regulatory Commission, to Linda Dewhirst, Nebraska Public Power District, dated September 15, 2021, "Cooper - Final RAI RE: Alternative Request RS-01 (EPID L-2021-LLR-0044)"
- 2.
Letter from John Dent, Jr., Nebraska Public Power District, to the U.S.
Nuclear Regulatory Commission, dated June 16, 2021, "10 CFR 50.55a Relief Request RS-01, Revision O"
Dear Sir or Madam:
The purpose of this letter is for the Nebraska Public Power District to respond to the Nuclear Regulatory Commission's request for additional information (RAI) (Reference 1) related to the Cooper Nuclear Station relief request related to snubber examination requirements (Reference 2).
The responses to the specific RAI questions are provided in Attachment 1 to this letter. contains snubber service life information.
This letter does not contain any new regulatory commitments.
If you have any questions concerning this matter, please contact Linda Dewhirst, Regulatory Affairs and Compliance Manager, at ( 402) 825-5416.
Sincerely,
~w O,t-- wbUl *-'kp,l~ &wd (fW~(ew, John Dent, Jr.
~
Vice President and Chief Nuclear Officer
/dv COOPER NUCLEAR STATION 72676 648A Ave/ P.O. Box 98 I Brownville, NE 68321 http://www.nppd.com
NLS2021058 Page 2 of2 Attachments:
- 1. Response to Nuclear Regulatory Commission Request for Additional Information (RAI)
- 2. Snubber Service Life and Expiration Dates cc:
Regional Administrator w/ attachments USNRC - Region IV Cooper Project Manager w/ attachments USNRC - NRR Plant Licensing Branch IV Senior Resident Inspector w/ attachments USNRC-CNS NPG Distribution w/ attachments CNS Records w/ attachments
NLS2021058 Page 1 of7 Response to Nuclear Regulatory Commission Request for Additional Information (RAI)
Cooper Nuclear Station, Docket No. 50-298, DPR-46 The Nuclear Regulatory Commission (NRC) request for additional information regarding the Alternative Request RS-1, is shown in italics. The Nebraska Public Power District (NPPD) response to the request is shown in normal font.
The implementation of Code Case OMN-13 requires that all provisions of Code Case OMN-13, Section 2, "General Requirements," be met before extension of the visual examination interval to once every 10 years. Cooper Alternative Request RS-01 and the Cooper fifth 10-year 1ST Program (ADAMS Accession No. MLI 6078Al 28) do not provide details about meeting these requirements. Explain how these general requirements to implement Code Case OMN-13 will be met.
NPPD Response:
In a letter dated April 9, 2008, NPPD notified the NRC that Cooper Nuclear Station (CNS) had adopted the American Society of Mechanical Engineers (ASME) Operation and Maintenance (OM) Code, Subsection ISTD, 2001 Edition through the 2003 Addenda, for snubber requirements (ADAMS Accession No. ML08 l 050254). With the adoption of ISTD, CNS also began the implementation of Revision O of Code Case OMN-13 [2001 Edition].
This version of Code Case OMN-13 was approved per Regulatory Guide 1.192 Revision O in June of 2003 and had been incorporated by reference into 10 CFR 50.55a.
General Requirement (a) of Code Case OMN-13 states that these [OMN-13] requirements are in addition to the service life monitoring requirements in ISTD 8 [ISTD-6000 Service Life Monitoring]. As a part of adopting the requirements ofISTD, CNS has followed the requirements ofISTD-6000 since implementing Code Case OMN-13.
General Requirement (b) states that the requirements of this Code Case shall be implemented after the requirements ofISTD 6.5.1 [ISTD-4251], ISTD 6.5.2(a) [ISTD-4252(a)], ISTD 6.5.2(b) [ISTD-4252(b)], and ISTD 6.5.2(c) [ISTD-4252(c)] have been satisfied and the previous examination per Table ISTD 6.5.2-1 [Table ISTD-4252-1] was performed at a maximum interval of two fuel cycles. Based on the 2001 Edition through the 2003 Addenda of the ASME OM Code, with CNS being more than 30 years into operation in 2008, ISTD 6.5.1 [ISTD-4251] for the initial inservice examination of snubbers, ISTD 6.5.2( a) [ISTD-4252(a)] for the second inservice examination of snubbers and a portion ofISTD 6.5.2(b)
[ISTD-4252(b)] for the third inservice examination of snubbers were not applicable to CNS at the time of implementation.
NLS2021058 Page 2 of7 The applicable part of General Requirement (b) for CNS in 2008 comes from a portion of ISTD 6.5.2(b) [ISTD-4252(b)], in which subsequent examinations shall be conducted in accordance with Table ISTD-4252-1. CNS performed examinations of 100% of its snubber population in Refueling Outage RE22 (February 2005) and two refueling outages earlier in RE20 (December 2001). All examinations in RE22 and RE20 were completed with satisfactory results. This meets the requirements of Table ISTD-4252-1 and the maximum interval of two fuel cycles. Since Table ISTD-4252-1 was met, ISTD-4252(c) was also not applicable to CNS in 2008.
General Requirement ( c) states to demonstrate that the requirements of paras. 3.1
[Examination for Indications of Degradation or Severe Operating Environments], 3.2
[Examination Prior to Maintenance or Testing], 3.3 [Monitoring of Reservoir Fluid Level], 3.4
[Review of Operational Readiness Test Data], 3.5 [Examination During Disassembly], and 3.6
[Transient Dynamic Event] of this Code Case have been met for one interval prior to extending the examination interval. All these characteristics were a part of the CNS Snubber Program prior to the implementation of OMN-13 and were demonstrated on a routine basis.
Therefore, the applicable General Requirements of OMN-13 were satisfied prior to entering Refueling Outage RE24 at CNS (April 2008).
Cooper's fifth 10-year interval began on March 1, 2016, and is scheduled to end on February 28, 2026. Cooper's fifth 10-year snubber program, Section 2.3 "Jnservice Examination, " states, in part, that Cooper is utilizing approved Code Case OMN-13. However, the program does not specify the date when Code Case OMN-13 was initially implemented to extend the visual examination interval from 48 months to up to 10 years. In addition, Cooper Alternative Request RS-01 does not specify when Code Case OMN-13 was initially implemented to extend the visual examination interval to up to 10 years. Provide the date when Code Case OMN-13 was initially implemented at Cooper.
NPPD Response:
Subsection ISTD and Code Case OMN-13 were initially implemented at CNS on April 7, 2008, when the update to the CNS Snubber Program administrative procedure, 3.39, was made effective. Then, as stated in the response to RAI-1, the NRC was notified via a letter, dated April 9, 2008, that CNS had adopted Subsection ISTD. Therefore, the benefits associated with OMN-13 were utilized beginning with Refueling Outage RE24, which began on April 12, 2008.
Cooper Alternative Request RS-01, Section 4, "Reason for Request," states, in part, that because of the strict 10-year interval requirement, Cooper would be implementing a less efficient overall program for the mechanical snubbers, and would be required to perform many
NLS2021058 Page 3 of7 mechanical/hydraulic snubber examinations on a four refueling cycle interval rather than every five refueling cycles. Explain how implementation of the Code Case OMN-13 requirements to complete the visual examination of all snubbers within 10 years is less efficient.
NPPD Response:
Approximately 74.5% of the CNS snubber program scope consists of mechanical snubbers (155 out of 208). As discussed in the initial submittal, the OMN-13 examinations are currently being performed in conjunction with the mechanical snubber service life activity that generally involves replacing the snubber with a pretested, rebuilt snubber at a maximum ten-year interval. This has resulted in an excellent performance history for the mechanical snubbers. CNS is proposing that a minimal grace period be applied to the OMN-13 ten-year examination interval to allow the OMN-13 examination and mechanical snubber service life activity to continue to be performed together once every 5 refueling outages.
For example, CNS currently has 36 mechanical snubber activities planned for RE32 (Fall 2022) in which the OMN-13 examination will be completed in addition to the snubbers being replaced with pretested, rebuilt snubbers. The OMN-13 examination due dates for 30 of the mechanical snubbers range from October 14, 2022 through November 2, 2022, since OMN-13 examinations were last performed in RE27 from October 14, 2012 through November 2, 2012.
The RE32 refueling outage is currently scheduled for October 1, 2022 through November 2, 2022. Although each one of these snubbers may be able to be examined prior to their respective OMN-13 due date in RE32, the concern that may arise is that the best time to perform certain examinations may be after the OMN-13 due date based on systems being out of service, outage scheduling conflicts, or maintenance resource issues. Also, the activities could be scheduled prior to the OMN-13 due dates, but unexpected delays in the outage may push one or more beyond the 10-year exam interval. For example, higher priority items may result in maintenance being pulled off the snubber activities for a few days. This clearly would not impact the effectiveness of the examination and/or service life replacement as all activities would be completed prior to startup, but it would place CNS at risk of being in a nonconformance with OMN-13 if approval of this reliefrequest was not obtained.
Additionally, without approval of this reliefrequest, some RE33 (Fall 2024) scope for mechanical snubbers may have to be considered for being added to RE32 (Fall 2022) to avoid the concerns described above for RE32. Separating these activities (i.e. performing the exam at 4 refueling outage intervals and replacement at 5 refueling outage intervals) or performing both more frequently at once every 4 refueling outage intervals would be less efficient than the current CNS approach of performing both activities at 5 refueling outage intervals. Over the life of the plant, this would result in more outage resources and radiological dose without a compensating increase in quality or safety.
Hydraulic snubbers represent approximately 25.5% of the snubber program scope at CNS (53 out of 208 snubbers ). The current service life of the hydraulic snubbers at CNS is 25 years.
However, for the same reasons as discussed above and bec~use they are more likely to be examined during the pre-outage time frame due to their locations, many of them may need to be
NLS2021058 Page 4 of7 scheduled to be examined once every 4 refueling outages rather than once every 5 refueling outages. Having to perform the examinations more frequently than once every 5 refueling outages is less efficient since CNS has had an excellent performance history for the hydraulic snubbers.
RAI-4
Code Case OMN-13, Section 3.4, "Review of Operational Readiness Test Data, " states that "All inservice test data acquired since implementation of the requirements of this Code Case shall be evaluated for indications of snubber degradation or other anomalies. This includes a review of test traces, where available. The results of its evaluation shall be used (a) to identify snubbers that are subject to progressive degradation, [and] (b) to identify severe operating environments not previously identified. " Summarize the snubber test data and evaluations since initial implementation of Code Case OMN-13, as required by Section 3. 4, to confirm the operational readiness of the snubbers beyond the 10-year interval.
NPPD Response:
CNS has experienced no programmatic examination or test failures since implementing OMN-13 in the Spring of 2008 (just prior to the start of RE24) through refueling outage RE31 (Fall 2020). The following paragraphs summarize the test data and examination results during this period.
CNS has utilized the 10% sample plan per ISTD-5300 for mechanical snubber testing. There are three design test plan groups (18 PSA-3, 89 PSA-10, and 48 PSA-35). From RE24 through RE31, 128 mechanical snubbers (16 per refueling outage) were selected for the 10% sample plan and all 128 were examined with satisfactory results in the as found position, then removed and as found tested with satisfactory results. These snubbers also satisfied the service life monitoring replacement activity as they were replaced with rebuilt, pretested snubbers that were installed and examined in the as left condition with satisfactory results.
Similarly, from RE24 through RE31, an additional 95 mechanical snubbers were selected to specifically satisfy the 10-year service life replacement activity for mechanical snubbers. All the examinations and testing associated with the service life replacement activities were also completed with satisfactory results. Although not required for service life replacements, beginning with RE27, all the service life snubber replacements have included as found tests on the removed snubbers. All the as found tests were completed with satisfactory results. This represents 70 of the 95 service life replacements that have occurred since RE24.
During this period from RE24 through RE31, only 3 examination discrepancies were identified with the mechanical snubbers. They were all associated with the cold snubber setting recorded during the examination not meeting the identified cold setting tolerances on the plant drawings.
These discrepancies were resolved by validating that the snubber would still operate within its normal stroke. One of these discrepancies identified in RE31 will be re-examined in RE32.
NLS2021058 Page 5 of 7 CNS has also utilized the 10% sample plan per ISTD-5300 for hydraulic snubber testing, which has one design test plan group of 53 snubbers. From RE24 through RE31, 48 hydraulic snubbers ( 6 per refueling outage) were selected for the 10% sample plan and all 48 were examined with satisfactory results in the as found position, then removed and as found tested with satisfactory results. Those selected during refueling outages RE24 through RE30 were also upgraded from Grinnell snubber model Figure 200 to an Anvil International (formerly Grinnell) Figure 200N Configuration A model and satisfied the service life replacement for the hydraulic snubber as well. By the end of RE30, all safety-related hydraulic snubbers had been upgraded to the Figure 200N Configuration A model.
Finally, in addition to the 10% sample testing/ service life replacement upgrades for the hydraulic snubbers, an additional 44 OMN-13 hydraulic snubber examinations were independently performed. All 44 of these examinations were completed with satisfactory results.
During the period from RE24 through RE3 l, one hydraulic snubber was replaced with an upgraded model in-between RE25 and RE26 after it was identified during a walkdown that the reservoir was cracked above the fluid level. The damage was believed to have been caused by workers in the area moving scaffold equipment. The removed snubber was as found tested with satisfactory results. Note that the next OMN-13 examination performed on this snubber was completed with satisfactory results on August 18, 2020. No other potential issues with safety-related hydraulic snubbers were identified within this period. This represented an anomaly not indicative of hydraulic snubber performance at CNS.
In conclusion, CNS has an excellent examination and test history for both the mechanical and hydraulic snubbers since initiating OMN-13. No programmatic examination or test failures have occurred. Additionally, no significant degradation or anomalies have been identified. As a result, no snubbers have been identified to be subjected to progressive degradation and no severe operating environments have been identified that would require the reduction of the existing service life. Moving forward, the same excellent examination and test results are expected to occur. Therefore, the proposed alternative will not impact the operational readiness of the CNS safety-related snubbers.
RAI-5
Code Case OMN-13, Section 2, "General Requirements," paragraph (a), states that the requirements in OMN-13 are in addition to the service life monitoring (SLM) requirements in ASME OM Code, Subsection !STD, paragraph ISTD-6000. ISTD-6000 requires that the service life of all snubbers be evaluated every refueling outage. Provide the service life and expiration dates of the 155 mechanical and 53 hydraulic snubbers evaluated during the previous refueling outage (RE31).
NLS2021058 Page 6 of7 NPPD Response:
The service life and expiration dates of the safety-related 155 mechanical snubbers and 53 hydraulic snubbers are being provided in Attachment 2.
Cooper Alternative Request RS-01, Section 5, "Proposed Alternative and Basis for Use," fourth paragraph, states, in part, that "CNS [Cooper J performs a service life snubber activity after approximately 10 years in service for all mechanical snubbers. " ISTD-6000 requires that the snubber service life be evaluated every refueling outage. Explain the discrepancy between the required service life evaluation every refueling outage (per ISTD-6000) versus the Cooper evaluation of service life approximately every 10 years.
NPPD Response:
The service life snubber activity after approximately 10 years in service for each mechanical snubber is in reference to a maintenance activity that currently examines the installed snubber, removes the installed snubber, replaces it with a rebuilt pretested snubber, performs an as left examination on the newly installed snubber, and performs an as found test on the removed snubber. This activity is not being utilized to satisfy the ISTD-6000 snubber service life evaluation. However, the examination and test results of the service life maintenance activities for each refueling outage are inputs to the snubber service life evaluation that is performed at least once each fuel cycle in accordance with ISTD-6000. Therefore, the 10-year service life activity and the ISTD-6000 service life evaluation represent two different requirements for the snubber program, both of which are being satisfied.
Cooper Alternative Request RS-01, Section 1, "ASME Code Component(s) Affected," proposes that the request apply to all snubbers covered by ASME OM Code, paragraph ISTA-1100, "Scope." However, Section 5 of the request discusses only mechanical snubbers. Provide the applicable information to support the alternative request for the Cooper hydraulic snubbers.
NPPD Response:
The portion of Section 5 that applies to the hydraulic snubbers in addition to the mechanical snubbers is that refueling outage RE32, scheduled for the Fall of 2022, represents the first refueling outage in which the full 24-month interval has occurred for five continuous cycles.
This means that from this time forward, hydraulic snubbers may come due for an OMN-13 examination just prior to the start of, during, or toward the end of the refueling outage, depending on the exact date of when the last OMN-13 exam was performed. Based on their location, many of the hydraulic snubbers are capable of being examined online and may have been performed during pre-outage time periods. Also, in addition to the mechanical snubbers, the safety-related CNS hydraulic snubbers have an excellent examination and test history.
NLS2021058 Page 7 of 7 As previously discussed, all safety-related programmatic hydraulic snubber examinations and testing have been completed with satisfactory results since the initial implementation of OMN-
- 13. Therefore, whether or not a hydraulic snubber exam is performed at an interval that is slightly less than 10 years during the snubber campaign period or slightly more than 10 years during the same snubber campaign period will not impact the reliability of the essential hydraulic snubbers. The snubber exam would still be completed within the same campaign period and any actions required prior to plant startup per ISTD and/or Code Case OMN-13 would still be implemented in the same manner. Without approval of this relief request, CNS may have to schedule hydraulic snubber exams at a nominal 8-year interval (4 refueling cycles) to ensure that the OMN-13 examination interval of 10 years is met. Based on the historical performance at CNS, performing these exams at a 4 refueling outage interval rather than a 5 refueling outage interval would not result in a compensating increase in reliability and/or safety.
RAI-8
Cooper Alternative Request RS-01 proposes to extend the visual examination interval for all 15 5 mechanical and 53 hydraulic snubbers beyond the JO-year interval. To enable the NRC staff to evaluate the operational readiness of the snubbers beyond 10 years, please summarize the historical data for the snubber examinations and testing performed after the initial implementation of Code Case OMN-13 at Cooper.
NPPD Response:
As stated in Section 5 of the proposed relief request and in the response to RAI-4, no snubber examination failures and/or test failures have occurred since the initial implementation of OMN-13 (April of2008). Refer to the response to RAI-4 for a detailed summary of the examination and test results since the initial implementation of OMN-13.
NLS2021058 Page 1 of9 Snubber Service Life and Expiration Dates Cooper Nuclear Station, Docket No. 50-298, DPR-46 CNS PSA-3 Mechanical Snubbers (18)
Service Date of Last Snubber Life Replacement Expiration Date CS-SNUB-(CS-VE7) 10 years 10/3/2018 10/3/2028 MS-SNUB-(MS-S 149B) 10 years 10/15/2012 10/15/2022 MS-SNUB-(MS-S 16) 10 years 8/8/2016 8/8/2026 MS-SNUB-(MS-S21) 10 years 10/14/2016 10/14/2026 MS-SNUB-(MS-S275) 10 years 9/23/2014 9/23/2024 MS-SNUB-(MS-S276) 10 years 9/24/2014 9/24/2024 MS-SNUB-(MS-S277) 10 years 9/23/2014 9/23/2024 MS-SNUB-(MS-S63) 10 years 10/12/2016 10/12/2026 MS-SNUB-(VR-S31) 10 years 10/18/2012 10/18/2022 MS-SNUB-(VR-S43) 10 years 10/5/2014 10/5/2024 MS-SNUB-(VR-S50A) 10 years 10/11/2016 10/11/2026 MS-SNUB-(VR-S50B) 10 years 10/12/2016 10/12/2026 RF-SNUB-(RF-S9) 10 years 10/3/2016 10/3/2026 RHR-SNUB-(RH-S 15) 10 years 10/15/2018 10/15/2028 RHR-SNUB-(RH-S65A) 10 years 10/8/2020 10/8/2030 RHR-SNUB-(RH-S65B) 10 years 10/8/2020 10/8/2030 RWCU-SNUB-(CU-S3A) 10 years 10/5/2014 10/5/2024 RWCU-SNUB-(CU-S3B) 10 years 10/18/2012 10/18/2022
NLS2021058 Page 2 of9 CNS PSA-10 Mechanical Snubbers (89)
Service Date of Last Snubber Life Replacement MS-SNUB-(MS-S22) 10 years 10/13/2016 MS-SNUB-(SS-B2) 10 years 10/2/2018 MS-SNUB-(SS-B3) 10 years 10/30/2012 MS-SNUB-(SS-C2) 10 years 10/10/2020 MS-SNUB-(SS-C3) 10 years 10/7/2016 MS-SNUB-(VR-55-9-Y) 10 years 10/8/2016 MS-SNUB-(VR-55-9-Z) 10 years 10/8/2016 MS-SNUB-(VR-56-12-Y) 10 years 9/29/2014 MS-SNUB-(VR-58-12-Y) 10 years 10/23/2012 MS-SNUB-(VR-59-7-X) 10 years 10/23/2012 MS-SNUB-(VR-59-7-Z) 10 years 10/7/2020 MS-SNUB-(VR-60-7-X) 10 years 10/8/2016 MS-SNUB-(VR-60-7-Z) 10 years 10/5/2018 MS-SNUB-(VR-61-8-X) 10 years 10/8/2016 MS-SNUB-(VR-62-17-X) 10 years 10/2/2014 MS-SNUB-(VR-62-8-X) 10 years 10/6/2020 MS-SNUB-(VR-H61D) 10 years 10/6/2020 MS-SNUB-(VR-H62B) 10 years 10/3/2016 MS-SNUB-(VR-H62C) 10 years 9/30/2014 MS-SNUB-(VR-H63B) 10 years 10/2/2016 MS-SNUB-(VR-H63 C) 10 years 10/5/2014 MS-SNUB-(VR-H64D) 10 years 10/16/2012 MS-SNUB-(VR-S 1) 10 years 10/11/2016 MS-SNUB-(VR-S 10) 10 years 10/31/2012 MS-SNUB-(VR-Sl 1) 10 years 9/30/2020 MS-SNUB-(VR-S14) 10 years 10/11/2016 MS-SNUB-(VR-S2) 10 years 10/5/2018 MS-SNUB-(VR-S23A) 10 years 10/7/2014 Expiration Date 10/13/2026 10/2/2028 10/30/2022 10/10/2030 10/7/2026 10/8/2026 10/8/2026 9/29/2024 10/23/2022 10/23/2022 10/7/2030 10/8/2026 10/5/2028 10/8/2026 10/2/2024 10/6/2030 10/6/2030 10/3/2026 9/30/2024 10/2/2026 10/5/2024 10/16/2022 10/11/2026 10/31/2022 9/30/2030 10/11/2026 10/5/2028 10/7/2024
NLS2021058 Page 3 of9 CNS PSA-10 Mechanical Snubbers (89)
Service Date of Last Snubber Life Replacement MS-SNUB-(VR-S23B) 10 years 10/7/2014 MS-SNUB-(VR-S24A) 10 years 10/1/2014 MS-SNUB-(VR-S24B) 10 years 10/7/2014 MS-SNUB-(VR-S26) 10 years 10/3/2018 MS-SNUB-(VR-S3) 10 years 11/2/2012 MS-SNUB-(VR-S30) 10 years 10/12/2016 MS-SNUB-(VR-S32) 10 years 10/8/2020 MS-SNUB-(VR-S4) 10 years 10/30/2012 MS-SNUB-(VR-S42A) 10 years 10/7/2014 MS-SNUB-(VR-S42B) 10 years 10/6/2020 MS-SNUB-(VR-S51) 10 years 10/29/2012 MS-SNUB-(VR-S6) 10 years 10/4/2018 MS-SNUB-(VR-S62A) 10 years 10/2/2018 MS-SNUB-(VR-S62B) 10 years 10/23/2012 MS-SNUB-(VR-S 71 A) 10 years 10/5/2018 MS-SNUB-(VR-S 71 B) 10 years 10/12/2016 MS-SNUB-(VR-S 7 4) 10 years 10/6/2014 MS-SNUB-(VR-S8) 10 years 10/23/2012 MS-SNUB-(VR-S81) 10 years 10/7/2020 MS-SNUB-(VR-S83A) 10 years 10/5/2020 MS-SNUB-(VR-S83B) 10 years 10/10/2014 MS-SNUB-(VR-S84) 10 years 10/13/2016 MS-SNUB-(VR-S85) 10 years 10/21/2012 MS-SNUB-(VR-S86A) 10 years 10/19/2016 MS-SNUB-(VR-S86B) 10 years 10/19/2016 MS-SNUB-(VR-S87 A) 10 years 10/11/2016 MS-SNUB-(VR-S87B) 10 years 10/7/2020 MS-SNUB-(VR-S88) 10 years 10/21/2012 PC-SNUB-(PV-S lAA) 10 years 10/8/2014 PC-SNUB-(PV-SlAB) 10 years 10/18/2012 Expiration Date 10/7/2024 10/1/2024 10/7/2024 10/3/2028 11/2/2022 10/12/2026 10/8/2030 10/30/2022 10/7/2024 10/6/2030 10/29/2022 10/4/2028 10/2/2028 10/23/2022 10/5/2028 10/12/2026 10/6/2024 10/23/2022 10/7/2030 10/5/2030 10/10/2024 10/13/2026 10/21/2022 10/19/2026 10/19/2026 10/11/2026 10/7/2030 10/21/2022 10/8/2024 10/18/2022
NLS2021058 Page 4 of9 CNS PSA-10 Mechanical Snubbers (89)
Service Date of Last Snubber Life Replacement RF-SNUB-(RF-S 10) 10 years 10/3/2016 RF-SNUB-(RF-Sl 1) 10 years 10/23/2018 RF-SNUB-(RF-S 12) 10 years 10/5/2020 RF-SNUB-(RF-S 14) 10 years 10/30/2012 RF-SNUB-(RF-S 15) 10 years 10/4/2020 RF-SNUB-(RF-S 16) 10 years 10/23/2018 RF-SNUB-(RF-S 1 7) 10 years 10/26/2012 RF-SNUB-(RF-S 18) 10 years 10/3/2016 RF-SNUB-(RF-S 19) 10 years 10/26/2012 RF-SNUB-(RF-S8) 10 years 10/7/2014 RHR-SNUB-(RH-Sl 1) 10 years 10/29/2012 RHR-SNUB-(RH-S14) 10 years 11/2/2012 RHR-SNUB-(RH-S 14A) 10 years 10/16/2020 RHR-SNUB-(RH-S2 l) 10 years 9/11/2018 RHR-SNUB-(RH-S29) 10 years 9/14/2016 RHR-SNUB-(RH-S3A) 10 years 10/16/2014 RHR-SNUB-(RH-S45) 10 years 10/13/2018 RHR-SNUB-(RH-S49) 10 years 10/18/2012 RHR-SNUB-(RH-S5) 10 years 10/1/2020 RHR-SNUB-(RH-S5 8) 10 years 10/2/2020 RHR-SNUB-(RH-S6) 10 years 10/1/2020 RHR-SNUB-(RH-S67) 10 years 10/9/2020 RHR-SNUB-(RH-S68) 10 years 11/1/2012 RHR-SNUB-(RH-S69A) 10 years 10/10/2014 RHR-SNUB-(RH-S69B) 10 years 10/21/2016 RHR-SNUB-(RH-S 70) 10 years 10/22/2016 RHR-SNUB-(RH-S 71) 10 years 10/21/2016 RHR-SNUB-(RH-S 73) 10 years 10/10/2020 RHR-SNUB-(RH-S8A) 10 years 10/26/2012 RHR-SNUB-(RH-S8B) 10 years 9/30/2020 RHR-SNUB-(RH-S8C) 10 years 10/26/2012 Expiration Date 10/3/2026 10/23/2028 10/5/2030 10/30/2022 10/4/2030 10/23/2028 10/26/2022 10/3/2026 10/26/2022 10/7/2024 10/29/2022 11/2/2022 10/16/2030 9/11/2028 9/14/2026 10/16/2024 10/13/2028 10/18/2022 10/1/2030 10/2/2030 10/1/2030 10/9/2030 11/1/2022 10/10/2024 10/21/2026 10/22/2026 10/21/2026 10/10/2030 10/26/2022 9/30/2030 10/26/2022
NLS2021058 Page 5 of9 CNS PSA-35 Mechanical Snubbers ( 48)
Service Date of Last Snubber Life Replacement MS-SNUB-(BS-S 1 B&R) 10 years 10/14/2012 MS-SNUB-(BS-S2A) 10 years 10/8/2014 MS-SNUB-(SS-A2) 10 years 10/11/2020 MS-SNUB-(SS-A3) 10 years 10/3/2020 MS-SNUB-(SS-D2) 10 years 10/4/2020 MS-SNUB-(SS-D3) 10 years 9/30/2020 MS-SNUB-(VR-55-23-X) 10 years 9/29/2020 MS-SNUB-(VR-55-26-Z) 10 years 10/2/2020 MS-SNUB-(VR-56-24-X) 10 years 10/9/2020 MS-SNUB-(VR-61-17-X) 10 years 10/10/2016 MS-SNUB-(VR-61-8-Z) 10 years 10/14/2016 MS-SNUB-(VR-62-8-Z) 10 years 10/7/2016 MS-SNUB-(VR-S 12) 10 years 10/18/2018 MS-SNUB-(VR-S20) 10 years 10/6/2014 MS-SNUB-(VR-S2 l) 10 years 10/10/2016 MS-SNUB-(VR-S22) 10 years 10/14/2016 MS-SNUB-(VR-S25) 10 years 10/11/2020 MS-SNUB-(VR-S27) 10 years 10/9/2020 MS-SNUB-(VR-S40) 10 years 10/8/2018 MS-SNUB-(VR-S4 l) 10 years 10/14/2016 MS-SNUB-(VR-S60) 10 years 10/4/2020 MS-SNUB-(VR-S6 l) 10 years 10/9/2018 MS-SNUB-(VR-S63) 10 years 10/9/2016 MS-SNUB-(VR-S72) 10 years 10/13/2016 MS-SNUB-(VR-S73) 10 years 10/6/2014 MS-SNUB-(VR-S7 A) 10 years 10/19/2012 MS-SNUB-(VR-S7B) 10 years 10/19/2012 MS-SNUB-(VR-S82) 10 years 10/12/2016 RF-SNUB-(RF-S 13) 10 years 10/3/2016 RHR-SNUB-(RH-S 10) 10 years 10/29/2012 RHR-SNUB-(RH-Sl6) 10 years 10/15/2020 Expiration Date 10/14/2022 10/8/2024 10/11/2030 10/3/2030 10/4/2030 9/30/2030 9/29/2030 10/2/2030 10/9/2030 10/10/2026 10/14/2026 10/7/2026 10/18/2028 10/6/2024 10/10/2026 10/14/2026 10/11/2030 10/9/2030 10/8/2028 10/14/2026 10/4/2030 10/9/2028 10/9/2026 10/13/2026 10/6/2024 10/19/2022 10/19/2022 10/12/2026 10/3/2026 10/29/2022 10/15/2030
NLS2021058 Page 6 of9 CNS PSA-35 Mechanical Snubbers ( 48)
Service Date of Last Snubber Life Replacement RHR-SNUB-(RH-S 17) 10 years 9/30/2014 RHR-SNUB-(RH-S 18) 10 years 10/21/2016 RHR-SNUB-(RH-S 19) 10 years 10/14/2020 RHR-SNUB-(RH-S72A) 10 years 10/18/2018 RHR-SNUB-(RH-S9) 10 years 11/1/2012 RR-SNUB-(SS-lA) 10 years 11/1/2012 RR-SNUB-(SS-1 B) 10 years 10/16/2018 RR-SNUB-(SS-2A) 10 years 11/2/2012 RR-SNUB-(SS-2B) 10 years 10/21/2012 RR-SNUB-(SS-3Al) 10 years 10/19/2016 RR-SNUB-(SS-3A2) 10 years 10/19/2016 RR-SNUB-(SS-3B 1) 10 years 10/17/2014 RR-SNUB-(SS-3B2) 10 years 10/18/2014 RR-SNUB-(SS-4A) 10 years 10/18/2016 RR-SNUB-(SS-4B) 10 years 10/17/2014 RR-SNUB-(SS-5A) 10 years 10/28/2012 RR-SNUB-(SS-5B) 10 years 10/28/2012 Expiration Date 9/30/2024 10/21/2026 10/14/2030 10/18/2028 11/1/2022 11/1/2022 10/16/2028 11/2/2022 10/21/2022 10/19/2026 10/19/2026 10/17/2024 10/18/2024 10/18/2026 10/17/2024 10/28/2022 10/28/2022
NLS2021058 Page 7 of9 CNS Hydraulic Snubbers (53)
Service Date of Last Snubber Life Replacement CS-SNUB-(CS-S 1) 25 years 2/23/2011 CS-SNUB-(CS-S2) 25 years 10/17/2009 CS-SNUB-(CS-S3) 25 years 10/17/2009 CS-SNUB-(CS-S6) 25 years 10/17/2009 CS-SNUB-(CS-S7) 25 years 10/16/2009 HPCI-SNUB-(HP-S 15) 25 years 10/2/2009 MS-SNUB-(BS-S 116A) 25 years 10/15/2012 MS-SNUB-(MS-S 19) 25 years 10/14/2012 MS-SNUB-(MS-S23) 25 years 10/16/2012 MS-SNUB-(MS-S3) 25 years 10/14/2012 MS-SNUB-(MS-S4) 25 years 4/16/2008 REC-SNUB-(RCC-S21) 25 years 4/26/2008 RHR-SNUB-(RH-S20) 25 years 9/7/2012 RHR-SNUB-(RH-S22) 25 years 1/3/2011 RHR-SNUB-(RH-S24) 25 years 1/4/2011 RHR-SNUB-(RH-S25) 25 years 3/5/2008 RHR-SNUB-(RH-S25A) 25 years 2/7/2011 RHR-SNUB-(RH-S26) 25 years 3/5/2008 RHR-SNUB-(RH-S3 OB) 25 years 9/14/2006 RHR-SNUB-(RH-S34) 25 years 9/16/2009 RHR-SNUB-(RH-S37) 25 years 9/18/2006 RHR-SNUB-(RH-S40) 25 years 9/18/2006 RHR-SNUB-(RH-S41) 25 years 4/9/2008 RHR-SNUB-(RH-S43) 25 years 9/20/2006 RHR-SNUB-(RH-S44A) 25 years 11/8/2006 Expiration Date 2/23/2036 10/17/2034 10/17/2034 10/17/2034 10/16/2034 10/2/2034 10/15/2037 10/14/2037 10/16/2037 10/14/2037 4/16/2033 4/26/2033 9/7/2037 1/3/2036 1/4/2036 3/5/2033 2/7/2036 3/5/2033 9/14/2031 9/16/2034 9/18/2031 9/18/2031 4/9/2033 9/20/2031 11/8/2031
NLS2021058 Page 8 of9 Snubber RHR-SNUB-(RH-S52)
RHR-SNUB-(RH-S55)
RHR-SNUB-(RH-S59)
RHR-SNUB-(RH-S 78A)
RHR-SNUB-(RH-S80)
RHR-SNUB-(RH-S96A)
CS-SNUB-(CS-S 11)
MS-SNUB-(BS-S 116B)
MS-SNUB-(MS-S 16B)
MS-SNUB-(MS-S2)
MS-SNUB-(MS-S25)
MS-SNUB-(MS-S 7 A)
MS-SNUB-(MS-S 7B)
REC-SNUB-(RCC-S20)
REC-SNUB-(RCC-S22)
RHR-SNUB-(RH-S27 A)
RHR-SNUB-(RH-S30A)
RHR-SNUB-(RH-S42)
RHR-SNUB-(RH-S44B)
RHR-SNUB-(RH-S48A)
RHR-SNUB-(RH-S48B)
RHR-SNUB-(RH-S54)
RHR-SNUB-(RH-S57)
RHR-SNUB-(RH-S76A)
RHR-SNUB-(RH-S76B)
Service Date of Last Life Replacement 25 years 9/7/2012 25 years 2/4/2011 25 years 10/21/2010 25 years 3/5/2008 25 years 10/26/2006 25 years 2/4/2011 25 years 8/9/2016 25 years 9/22/2014 25 years 9/23/2014 25 years 10/8/2014 25 years 9/11/2018 25 years 9/12/2018 25 years 9/12/2018 25 years 8/23/2016 25 years 8/23/2016 25 years 9/25/2014 25 years 9/11/2014 25 years 8/18/2016 25 years 10/12/2018 25 years 10/4/2016 25 years 10/4/2016 25 years 9/20/2018 25 years 8/11/2016 25 years 10/19/2018 25 years 10/18/2018 Expiration Date 9/7/2037 2/4/2036 10/21/2035 3/5/2033 10/26/2031 2/4/2036 8/9/2041 9/22/2039 9/23/2039 10/8/2039 9/11/2043 9/12/2043 9/12/2043 8/23/2041 8/23/2041 9/25/2039 9/11/2039 8/18/2041 10/12/2043 10/4/2041 10/4/2041 9/20/2043 8/11/2041 10/19/2043 10/18/2043
NLS2021058 Page 9 of9 Snubber RHR-SNUB-(RH-S 77)
RHR-SNUB-(RH-S78B)
RHR-SNUB-(RH-S98)
Service Date of Last Life Replacement Expiration Date 25 years 10/4/2016 10/4/2041 25 years 10/5/2016 10/5/2041 25 years 10/15/2014 10/15/2039