ML24067A251
| ML24067A251 | |
| Person / Time | |
|---|---|
| Site: | Susquehanna  |
| Issue date: | 03/19/2024 |
| From: | Hipolito Gonzalez Plant Licensing Branch 1 |
| To: | Casulli E Susquehanna |
| Klett A | |
| References | |
| EPID L-2023-LLR-0027 | |
| Download: ML24067A251 (1) | |
Text
March 19, 2024
Edward Casulli Site Vice President Susquehanna Nuclear, LLC 769 Salem Boulevard NUCSB3 Berwick, PA 18603-0467
SUBJECT:
SUSQUEHANNA STEAM ELECTRIC STATION, UNITS 1 AND 2 -
AUTHORIZED ALTERNATIVE TO REQUIREMENTS OF THE ASME CODE (EPID L-2023-LLR-0027)
Dear Edward Casulli:
By letter dated June 1, 2023, as supplemented by letter dated November 8, 2023, Susquehanna Nuclear, LLC (the licensee) submitted Relief Request 5RR-02 (a proposed alternative) to the U.S. Nuclear Regulatory Commission. The licensee requested to use an alternative to certain requirements in the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME BPV Code),Section XI, for the Susquehanna Steam Electric Station, Units 1 and 2 (Susquehanna).
Specifically, pursuant to Title 10 of the Code of Federal Regulations (10 CFR),
Section 50.55a(z)(1), the licensee requested to use the proposed alternative on the basis that the alternative provides an acceptable level of quality and safety.
The NRC staff has reviewed the subject request and concludes, as set forth in the enclosed safety evaluation, that the licensee has adequately addressed all the regulatory requirements set forth in 10 CFR 50.55a(z)(1).
All other ASME BPV Code,Section XI, requirements for which an alternative was not specifically requested and authorized remain applicable, including third-party review by the authorized nuclear inservice inspector.
E. Casulli
If you have any questions, please contact Audrey Klett (NRCs licensing project manager for Susquehanna) at (301) 415-0489 or Audrey.Klett@nrc.gov.
Sincerely,
Hipólito González, Chief Plant Licensing Branch I Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation
Docket Nos. 50-387 and 50-388
Enclosure:
Safety Evaluation
cc: Listserv
March 19, 2024
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION FOR RELIEF REQUEST 5RR-02 (PROPOSED ALTERNATIVE)
FIFTH 10-YEAR SNUBBER PROGRAM INTERVAL FIFTH 10-YEAR INSERVICE INSPECTION INTERVAL SUSQUEHANNA NUCLEAR, LLC ALLEGHENY ELECTRIC COOPERATIVE, INC.
SUSQUEHANNA STEAM ELECTRIC STATION, UNIT 1 AND UNIT 2 DOCKET NOS. 50-387 and 50-388
1.0 INTRODUCTION
By letter dated June 1, 2023 (Agencywide Documents Access and Management System Accession No. ML23152A244), as supplemented by letter dated November 8, 2023 (ML23312A177), Susquehanna Nuclear, LLC (the licensee) submitted Relief Request 5RR-02 (a proposed alternative) to the U.S. Nuclear Regulatory Commission (NRC). The licensee requested to use an alternative to certain requirements in the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (BPV Code),Section XI, Rules for Inservice Inspection of Nuclear Power Plant Components, for examination boundaries and sample size of snubbers during the fifth 10-year inservice inspection (ISI) interval at the Susquehanna Steam Electric Station, Units 1 and 2 (Susquehanna).
Pursuant to Title 10 of the Code of Federal Regulations (10 CFR), Section 50.55a(z)(1), the licensee requested to use the proposed alternative on the basis that the alternative provides an acceptable level of quality and safety.
2.0 REGULATORY EVALUATION
2.1 Regulations
The regulations in 10 CFR 50.55a(z)(1) state, in part, that alternatives to the requirements of paragraphs (b) through (h) of 10 CFR 50.55a may be used when authorized by the NRC if the proposed alternative would provide an acceptable level of quality and safety.
The regulations in 10 CFR 50.55a(b)(3)(v), OM condition: Snubbers ISTD, state:
Article IWF-5000, Inservice Inspection Requirements for Snubbers, of the ASME BPV Code,Section XI, must be used when performing inservice inspection examinations and tests of snubbers at nuclear power plants, except as conditioned in [10 CFR 50.55a(b)(3)(A) and (B)].
(A) Snubbers: First provision. Licensees may use Subsection ISTD, Preservice and Inservice Examination and Testing of Dynamic Restraints (Snubbers) in Light-Water Reactor Power Plants, ASME OM Code [American Society of
Enclosure
Mechanical Engineers Operation and Maintenance Code, Operation and Maintenance of Nuclear Power Plants], 1995 Edition through the latest edition and addenda incorporated by reference in [10 CFR 50.55a(1)(iv)], in place of the requirements for snubbers in the editions and addenda up to the 2005 Addenda of the ASME BPV Code,Section XI, IWF-5200(a) and (b) and IWF-5300(a) and (b), by making appropriate changes to their technical specifications or licensee-controlled documents. Preservice and inservice examinations must be performed using the VT-3 visual examination method described in IWA-2213.
(B) Snubbers: Second provision. Licensees must comply with the provisions for examining and testing snubbers in Subsection ISTD of the ASME OM Code and make appropriate changes to their technical specifications or licensee-controlled documents when using the 2006 Addenda and later editions and addenda of Section XI of the ASME BPV Code.
The regulations in 10 CFR 50.55a(f)(4), Inservice testing standards requirement for operating plants, state, in part:
When using the 2006 Addenda or later of the ASME BPV Code,Section XI, the inservice examination, testing, and service life monitoring requirements for dynamic restraints (snubbers) must meet the requirements set forth in the applicable ASME OM Code as specified in [10 CFR 50.55a(b)(3)(v)(B)].
The regulations in 10 CFR 50.55a(g)(4), Inservice inspection standards requirement for operating plants, state, in part:
Throughout the service life of a boiling or pressurized water-cooled nuclear power facility, components (including supports) that are classified as ASME Code Class 1, Class 2, and Class 3 must m eet the requirements, except design and access provisions and preservice examination requirements, set forth in Section XI of editions and addenda of the ASME BPV Code that become effective subsequent to editions specified in [10 CFR 50.55a(g)(2) and (3)] and that are incorporated by reference in [10 CFR 50.55a(a)(1)(ii) or (iv)] for snubber examination and testing of this section, to the extent practical within the limitations of design, geometry, and materials of construction of the components.
Components that are classified as Class MC pressure retaining components and their integral attachments, and components that are classified as Class CC pressure retaining components and their integral attachments, must meet the requirements, except design and access provisions and preservice examination requirements, set forth in Section XI of the ASME BPV Code and addenda that are incorporated by reference in [10 CFR 50.55a(a)(1)(ii)] subject to the condition listed in [10 CFR 50.55a(b)(2)(vi)] and the conditions listed in
[10 CFR 50.55a(b)(2)(viii) and (ix)], to the extent practical within the limitation of design, geometry, and materials of construction of the components. When using the 2006 Addenda or later of the ASME BPV Code,Section XI, the inservice examination, testing, and service life monitoring requirements for dynamic restraints (snubbers) must meet the requirements set forth in the applicable ASME OM Code as specified in [10 CFR 50.55a(b)(3)(v)(B)].
The regulations in 10 CFR 50.55a(g)(4)(ii), Applicable ISI Code: Successive 120-month intervals, state, in part:
Inservice examination of components and system pressure tests conducted during successive 120-month inspection intervals must comply with the requirements of the latest edition and addenda of the ASME Code incorporated by reference in [10 CFR 50.55a(a)] 18 months before the start of the 120-month inspection interval (or the optional ASME Code Cases listed in NRC Regulatory Guide 1.147, when using ASME BPV Code,Section XI, or NRC Regulatory Guide 1.192, when using the ASME OM Code, as incorporated by reference in [10 CFR 50.55a(a)(3)(ii) and (iii)], subject to the conditions listed in
[10 CFR 50.55a(b)].
2.2 ASME Code
Applicable Code Edition
Susquehannas fifth 10-year snubber and ISI program intervals are scheduled to start on June 1, 2024, and scheduled to end on May 31, 2034. In its supplement, the licensee stated that for each individual support, its respective attachment hardware and snubber inspection requirements under each program will align on day one of the fifth interval.
The applicable code of record for the fifth 10-year ISI program interval is the 2019 Edition of ASME BPV Code,Section XI.1
The applicable code of record for the fifth 10-year snubber program interval is the 2020 Edition of the ASME OM Code,2 as incorporated by reference in 10 CFR 50.55a.
Applicable Code Requirements
The ASME BPV Code,Section XI, Subarticle IWF-1300, Support Examination Boundaries, Figure IWF-1300-1, Illustrations of Typical Support Examination Boundaries, illustration (f) depicts the examination boundaries for snubbers. The boundaries indicate that the attachment of the snubber to the pressure boundary and building structure is required to be examined in accordance with ASME BPV Code,Section XI, Article IWF-2000, Examination and Inspection.
The NRC staff considered the following ISI exami nation requirements for supports and their attachments (without snubbers, pin-to-pin) from the ASME BPV Code,Section XI, as incorporated by reference in 10 CFR 50.55a, for evaluating the licensees proposed alternative:
Article IWA-2000, Examination and Inspection, and Paragraph IWA-2213, VT-3 Examination, provide details regarding the inspection and methods of inspection, respectively.
Subsection IWF provides requirements for Class 1, 2, 3, and MC component supports, and Article IWF-1000 provides requirements on scope and responsibilities.
1 All references to ASME BPV Code,Section XI in this document are to Edition 2019 unless another edition is explicitly cited.
2 All references to ASME OM Code in this document are to Edition 2020 unless another edition is explicitly cited.
Article IWF-1200, Component Supports Subject to Examination and Test, subsubarticle IWF-1220, Snubber Inspection Requirements, states, The inservice inspection requirements for snubbers are outside the scope of this Division. Endnote No. 39 for subsubarticle IWF-1220 states that examination and test requirements for snubbers can be found in the ASME OM Code.
Subarticle IWF-1300, Support Examination Boundaries, paragraph (h) states, The examination boundary of a support containing a snubber shall not include the connections to the snubber assembly (pins).
Subarticle IWF-1300 contains Figure IWF-1300-1(f), which depicts the examination boundaries for snubbers and their attachments and supports.
Article IWF-2000, Examination and Inspection, provides requirements for the examination and inspection of component supports.
Subsubarticles IWF-2210, Initial Examination, and IWF-2430, Additional Exanimation, require component examinations to be performed in accordance with Table IWF-2500-1 (F-A), Examination Category F-A, Supports.
Table IWF-2500-1 requires a VT-3 visual examination of Class 1 piping supports (item no. F1.10 in the table), Class 2 piping supports (F1.20), Class 3 piping supports (F1.30) piping supports, and supports other than piping supports (Class 1, 2, and 3; item no. F1.40). The table also identifies required percentages of supports to examine for each class: Class 1 (25 %), Class 2 (15%), and Class 3 (10%). Note 4 of the table states, in part, that the total percentage sample shall be comprised of supports from each system, where the individual sample sizes are proportional to the total number of non-exempt supports of each type and function within each system. For item no. F1.40 components, 100 % of the supports require examination, unless there are multiple components other than piping within a system of similar design, function, and service. In that case, the supports of only one of the multiple components are required to be examined.
Article IWF-3000, Acceptance Standards, provides acceptance standards for supports.
The NRC staff considered the following inservice testing and examination requirements for snubbers (pin-to-pin) from the ASME OM Code, as incorporated in 10 CFR 50.55a, for this alternative request:
Subsection ISTD, Preservice and Inservice Requirements for Dynamic Restraints (Snubbers) in Water-Cooled Reactor Nuclear Power Plants, Article ISTD-4000, Specific Examination Requirements, which includes Subarticle ISTD-4100, Preservice Examination, and Subarticle ISTD-4200, Inservice Examination.
Table ISTD-4252-1, Visual Examination Table, Note 2, states, The basic interval shall be the normal fuel cycle up to 24 months. The examination interval may be as great as twice [48 months], the same, or as small as fractions of the previous interval as required by [notes 3 through 6]. The examination interval may vary +/- [plus or minus] 25 % only to accommodate an extended outage or an unplanned event during the examination interval. The +/-25 % variance is specifically not to be used to extend an examination for an additional refueling cycle.
Subsection ISTA, General Requirements, Subarticle ISTA-1500, Owners Responsibilities, requires, in part, preparation of plans and schedule; preparation of written tests and examination instructions and procedures; and qualification of personnel who perform and evaluate examinations and tests in accordance with the owners quality assurance program.
Code Case OMN-13, Revision 3, Performance-Based Requirements for Extending Snubber Inservice Visual Examination Interval at LWR [Light-Water Reactor] Power Plants, 3 establishes specific requirements that must be met to allow extension of the interval for visual examination of snubbers up to once every 10 years.
3.0 TECHNICAL EVALUATION
3.1 Proposed Alternative
ASME Code Components Affected
Description:
alternative examination of snubber attachments Component Number: all Class 1, 2 and 3 snubber attachments Code Class 1, 2, and 3
Reference:
Table IWF-2500-1 Examination Category: F-A, supports Item Number: F1.10, F1.20, F1.30, and F1.40
Proposed Alternative
The licensee proposed to perform all Class 1, 2, and 3 snubber attachments ISI examination under the ASME OM Code instead of ASME BPV Code,Section XI. The licensees request applied only to supports that contain snubbers.
Specifically, the licensee requested a proposed alternative to the requirements of ASME BPV Code,Section XI, Table IWF-2500-1, which requires VT-3 visual examination of Class 1, 2, and 3 piping supports (item nos. F1.10, F1.20, and F1.30 in the table, respectively), and Class 1, 2, and 3 component supports (item no. F1.40 in the table). In its supplement, the licensee stated that it is requesting an alternative to the periodic inspection requirements of Table IWF-2410-1 for snubber supports only.
The licensee proposed that the examinations of snubbers and their associated attachments be administered and scheduled per the stations snubber program under the requirements of the ASME OM Code. In its supplement, the licensee stated that it would use the ASME OM Code for visual inspection of snubbers, including t he ASME OM Code Case OMN-13 requirement for snubbers during the extended interval of 10 years. If the number of unacceptable snubbers (pin-to-pin), which can be found during non-inspection activities such as walkdowns or events, exceeds ASME OM Code, Table ISTD-4252-1 limits, then the current examination interval shall end, and all remaining examinations will be completed within the current cycle.
In its supplement, the licensee clarified that it would inspect all snubber supports in accordance with the requirements of ASME OM Code Case OMN-13. Specifically, 100 % of snubber supports would be inspected over the 10-year interval with an expanded inspection boundary as shown in figure 2 of the submittal. The licensee would exclude snubber supports from the population of supports subject to Table IWF-2500-1. The licensee stated that the examination method used for the snubbers and their attachments will be a VT-3 visual examination in accordance with ASME BPV Code,Section XI, Paragraph IWA-2213. In its submittal, the
3 All references to ASME OM Code Case OMN-13 in this document are to Revision 3 unless another revision is explicitly cited.
licensee stated that VT-3 visual examinations of the associated supports attachments will be performed at the same time as the required visual examination of the snubber. For those snubber attachments that are covered by insulation, the licensee stated that the insulation will be removed prior to the VT-3 visual examination.
In its supplement, the licensee stated that this alternative would exceed the sample size requirements of ASME BPV Code,Section XI, Table IWF-2500-1 because 100 % of snubber supports would be inspected, while non-snubber Class 1, 2 and 3 supports would be inspected on a sampling basis of 25 %, 15 %, and 10 %, respectively. Non-snubber supports would be inspected on the periodicity defined in Table IWF-2410-1, while snubber supports would deviate from the interval (i.e., 3-, 7-, and 10-year) requirements of Table IWF-2410-1 but still be required to have all testing completed within the 10-year interval.
The licensee stated that examinations of non-snubber supports and their associated attachments will continue to be administered and scheduled per the stations ISI program under the requirements of the ASME BPV Code,Section XI. Specifically, the non-snubber supports would be examined at the required sample sizes and be periodicity specified by Tables IWF-2500-1 and IWF-2410-1, respectively (i.e., all non-snubber supports would follow existing Subsection IWF requirements.) In its supplement, the licensee stated that snubber supports would be excluded from the population of supports subject to Table IWF-2500-1 (i.e., snubber support inspections will not be counted toward the population or sample requirements of Table IWF-2500-1.)
In its supplement, the licensee cl arified that it would follow the requirement of ASME BPV Code,Section XI, Subsubarticle IWF-2430 to examine the supports immediately adjacent to a snubber that is found exceeding the acceptance standards and to take corrective measures or repair/replacement activities, regardless of whether the adjacent support includes a snubber.
The licensee clarified that the proposed alternative is related to the sample size and inspection schedule of snubber supports and that the alternative would not affect compliance with Subsubarticle IWF-2430 for snubber or non-snubber related supports.
In its supplement, the license stated that a new snubber support installation that is a repair/replacement activity will have preservice examinations performed in accordance with ASME BPV Code,Section XI, Table IWF-2500-1. The licensee stated that it would schedule inservice inspections during the fifth ISI and snubber program intervals in accordance with its proposed alternative and ASME OM Code Case OMN-13. A new non-snubber support installation considered a repair/replacement ac tivity will have preservice examinations performed in accordance with ASME BPV Code,Section XI, Table IWF-2500-1. The licensee would schedule inservice inspections during t he fifth ISI and snubber program interval in accordance with Subparagraph IWF-2410(c).
Licensees Basis for Use
The ASME OM Code Case OMN-13 requires 100 % safety related snubbers to be examined and evaluated at least once every 10 years. This exceeds the requirements of ASME BPV Code,Section XI, Table IWF-2500-1, which only requires 25 % of F1.10, 15 % of F1.20, and 10 % of F1.30 supports required to be examined over a 10-year interval. The licensee stated that it has met the general requirements stated in section 2 of ASME OM Code Case OMN-13.
The licensee indicated that if the number of unacceptable snubbers exceed the limits as prescribed in ASME OM Code, Table ISTD-4252-1, then a reduction in the frequency interval of visual examinations would occur (i.e., the examinations would occur more frequently). Only
snubbers and their associated attachments would be under the requirements of the reduced visual inspection frequency.
The licensee stated that under the stations ISI program, the requirements of ASME BPV Code,Section XI, Subsubarticle IWF-2430 would continue to be followed for supports. Specifically, if examination of a support reveals a flaw or relevant condition exceeding the acceptance standards of Subarticle IWF-3400 and requires corrective measures or repair/replacement activities in accordance with Subparagraph IWF-3122.2, then the examination (including examination of snubbers) would extend during the current outage in accordance with Subparagraphs IWF-2430(a)(1) and (2). Subsubarticle IWF-2430 requires examination of the supports, which are immediately adjacent to a snubber that is found exceeding the acceptance standards and requires corrective measures or repair/replacement activities, regardless of whether the adjacent support includes a snubber. New supports (without snubbers) would be examined in accordance with the ASME BPV Code,Section XI, Subparagraph IWF-2410(c).
The licensee stated that under the stations snubber program, if a snubber or its associated attachment fails its visual examination, then the snubber would be removed for functional testing. The visual failure and the reason for the failure would also be entered into the stations corrective action program system. If the snubber fails its functional test, then it is considered a visual failure, and the requirements of ASME OM Code, ISTD-4240 apply. Newly added snubbers would be examined in accordance with the ASME OM Code.
The licensee stated that examining both boundaries via the stations snubber program using VT-3 visual examination-qualified personnel would provide a better understanding of the snubber and attachments. The licensee stated that this would meet the visual examination requirements of both the ASME OM Code and ASME BPV Code. The licensee indicated that the alternative would be a dose and time saving effort because it would reduce the number of required examinations and personnel required to accomplish both requirements with one examination. Performing the examination of 100 % of the snubber attachments in accordance with the ASME OM Code frequency would exceed the examination percentage requirements defined in the ASME BPV Code,Section XI.
Reason for the Proposed Alternative
Inservice inspection requirements for snubbers were removed from the scope of ASME BPV Code,Section XI, starting in the 2004 Edition with the 2006 Addenda but were included in the ASME OM Code. Figure IWF-1300-1(f) was added to the ASME BPV Code,Section XI, to show the examination boundaries for snubbers, which excluded the body of the snubber, including the pivot and clevis pin (Figure IWF-1300-1(f) is shown in figure 1 on the next page).
Figure 1 Typical Support Examination Boundaries
Source: 2019 Edition of the ASME BPV Code,Section XI, Figure IWF-1300-1
The attachments for the snubber to the pressure boundary (e.g., via pipe clamps) and to the building structure are still included as part of the examination boundary per the ASME BPV Code,Section XI. Therefore, both the stati ons snubber and lSI programs require tracking and scheduling two different examination boundaries for snubber components.
To eliminate the duplication of effort by tracking two different examination boundaries for snubbers, the licensee proposed to incorporate both examination boundaries, as shown in figure 2 on the following page, into its snubber program. This combined boundary will include all items listed in ASME BPV Code,Section XI, Subarticle IWF-2500. The licensee stated that incorporating both examination boundaries into one program would provide a better understanding of the condition of the snubber and its associated attachment to the pressure boundary or building structure. The licensee stated that a 100 % visual examination of all safety-related snubbers would be performed on an examination frequency determined by the ASME OM Code and ASME OM Code Case OMN-13. 4 The examination method used for snubbers and their attachments would be the VT-3 visual examination in accordance with ASME BPV Code,Section XI, Paragraph IWA-2213.
4 In Revision 4 of NRC Regulatory Guide 1.192, Operation and Maintenance Code Case Acceptability, ASME OM Code (ML21181A223), the NRC staff approved ASME OM Code Case OMN-13, Revision 3 (2020 Edition), for use as a voluntary alternative to the mandatory ASME OM Code provisions that are incorporated by reference in 10 CFR 50.55a.
Figure 2 Proposed Alternative Examination Boundaries
Source: Licensees submittal ( ML23152A244)
3.2 NRC Staff Evaluation
The NRC staff evaluated the licensees proposed alternative, including the snubber (pin-to-pin) inservice examination requirements and the snubber attachment visual examination requirements.
The stations fifth 10-year snubber program interval is based on the 2020 Edition of the ASME OM Code, whereas the visual inspection of snubber attachments and non-snubber supports (pressure boundary attachment to the building attachment) for the fifth 10-year ISI interval is based on the 2019 Edition of the ASME BPV Code,Section XI.
The ASME BPV Code,Section XI, Figure IWF-1300- 1(f) depicts the examination boundaries for a snubber, as shown in figure 1. The boundaries indicate that the attachment of the snubber to the pressure boundary and building structure is required to be examined in accordance with Article IWF-2000, whereas the excluded snubber (pin-to-pin) is required to be examined per the ASME OM Code.
To eliminate the duplication of effort by tracking two different examination boundaries for one component (snubber and its attachment and associated support), the licensee requested an alternative to establish one examination boundary, as shown previously in figure 2.
Incorporating both examination boundaries into one program would also provide a better understanding of the condition of the snubber and its associated attachment to the pressure boundary or building structure.
The NRC staff reviewed the information provided in licensees submittal, as supplemented. The staff finds the proposed examination boundaries of snubbers and attachments as shown in figure 2, in lieu of the boundaries shown in figure 1, are acceptable for the following reasons:
(1) Incorporating both examination boundaries (snubbers and their attachments and associated supports) into one program provides a better understanding of the condition of a snubber and its associated attachments, without impacting quality and safety.
(2) The licensee stated that it will use VT-3 qualified personnel for both snubbers and associated attachments and supports. Performing both visual examinations of a snubber and its attachments and supports under the proposed boundaries in the snubber program using VT-3 qualified personnel to perform examinations provides a better understanding of the snubber and attachments.
(3) ASME BPV Code Section XI did not specify the boundaries between a snubber and its attachments and supports. In the 2006 Addenda of the ASME BPV Code,Section XI, the new boundaries between the snubber and its attachments were introduced via Figure IWF-1300-1(f) because the snubber (pin-to-pin) examination and testing were moved to the ASME OM Code. Visual examination of snubber attachments by VT-3 qualified personnel meets the inspection requirement of ASME BPV Code,Section XI.
(4) The licensee stated that the station meets the provisions in section 2 of ASME OM Code Case OMN-13. Furthermore, the licensee stated that, as specified in section 3.7(b) of ASME OM Code Case OMN-13, if the number of unacceptable snubbers exceed the limits in prescribed in ASME OM Code, Table ISTD-4252-1, then the frequency interval of visual examinations will be reduced for snubber examination (i.e., the examinations would occur more frequently).
(5) ASME OM Code Case OMN-13 requires 100 % of safety-related snubbers to be examined and evaluated at least once every 10 years. Based on the proposed boundaries of figure 2, the licensee will also perform 100 %visual examination of snubber attachments along with the snubbers. This exceeds the requirements of the ASME BPV Code,Section XI, Table IWF-2500-1 (for attachments), which only specifies that 25 % of Class 1, 15 % of Class 2, and 10 % of Class 3 supports be inspected over a 10-year interval.
(6) Visual examination of the snubber and associated attachments would be performed at the same time.
Based on the above, the NRC staff finds that the licensees proposed alternative of boundaries as specified in figure 2, which includes the snubber and its attachments, meets or exceeds the inspection requirements of ASME BPV Code,Section XI, Article IWF-2000 and, therefore, provides an acceptable level of quality and safety. The NRC staff also finds it acceptable for the licensee to track snubber attachment inspections vi a the stations snubber program in lieu of the ISI program.
4.0 CONCLUSION
As described above, the NRC staff determines that the licensees proposed alternative provides an acceptable level of quality and safety. Accordingly, the NRC staff concludes that the licensee has adequately addressed the regulatory requirements set forth in 10 CFR 50.55a(z)(1).
Therefore, the NRC staff authorizes the use of proposed alternative as documented in the licensees submittal, as supplemented, at Susquehanna for the fifth 10-year snubber and ISI program intervals, which will commence on June 1, 2024, and are scheduled to end on May 31, 2034.
All other 10 CFR 50.55a and ASME BPV Code,Section XI, requirements for which an alternative was not specifically requested and authorized remain applicable, including third-party review by the authorized nuclear inservice inspector.
5.0 PRINCIPAL CONTRIBUTORS
G. Bedi, NRR N. Chandran, NRR T. Scarbrough, NRR S. Cumblidge, NRR
ML24067A251 OFFICE NRR/DORL/LPL1/PM NRR/DORL/LPL1/LA NRR/DNRL/NPHP/BC NAME AKlett KZeleznock MMitchell DATE 03/07/2024 03/14/2024 02/14/2024 OFFICE NRR/DEX/EMIB/BC NRR/DORL/LPL1/BC NAME SBailey HGonzález (RGuzman for)
DATE 02/20/2024 03/19/2024