ML22133A003

SLRA Rai'S Set 1

ML22133A003
Person / Time
Site:	Saint Lucie
Issue date:	05/12/2022
From:	Harris B NRC/NRR/DNRL/NLRP
To:	Florida Power & Light Co
Harris B, 301-415-2277
Shared Package
ML22133A001	List: ML22133A003
References
Download: ML22133A003 (23)

Text

ST. LUCIE NUCLEAR PLANT, UNITS 1 AND 2 SUBSEQUENT LICENSE RENEWAL APPLICATION (SLRA)

REQUESTS FOR ADDITIONAL INFORMATION (SET #1)

SAFETY REVIEW RAI B.2.3.3-1 Regulatory Basis 10 CFR 54.21(a)(3) requires an applicant to demonstrate that the effects of aging for structures and components will be adequately managed so that the intended function(s) will be maintained consistent with the current licensing basis for the period of extended operation. One of the findings that the staff must make to issue a renewed license (10 CFR 54.29(a)) is that actions have been identified and have been or will be taken with respect to managing the effects of aging during the period of extended operation on the functionality of structures and components that have been identified to require review under 10 CFR 54.21, such that there is reasonable assurance that the activities authorized by the renewed license will continue to be conducted in accordance with the current licensing basis. To complete its review and enable the staff to make a finding under 10 CFR 54.29(a), the staff requires additional information in regard to the matters described below.

Background

St. Lucie SLRA Section B.2.3.3 describes the applicants aging management program (AMP) for the reactor head closure stud bolting (studs, nuts, washers, and threads-in-flange) of the St.

Lucie units. By letter dated January 27, 2020 (ADAMS Accession No. ML20027B419), the applicant requested relief from the inspection schedule specified in the ASME Code,Section XI for examination of the studs, nuts, and washers (the threads-in-flange are not included in the relief) for the St. Lucie Unit 1 fifth 10-year inservice inspection (ISI) interval and for the St. Lucie Unit 2 fourth 10-year ISI interval The applicant stated that it had requested relief in order to accommodate an additional set of reactor head closure studs, nuts, and washers that are shared in rotation between the St. Lucie units. The staff issued the safety evaluation for this proposed relief by letter dated February 17, 2021 (ADAMS Accession No. ML21027A226).

Associated with this proposed relief, the applicant is taking an exception to Element 4, Detection of Aging Effects of the AMP in GALL-SLR because the use of three sets of reactor vessel closure studs, nuts, and washers (instead of just two sets) does not make it feasible to maintain an inspection cycle that meets the ASME Code,Section XI requirements. Additionally, based on its audit of the AMP in the St. Lucie SLRA, the staff identified an exception to Element 5, Monitoring and Trending of the AMP in GALL-SLR, because this element also refers to the ASME Code,Section XI, inspection requirements for the reactor vessel closure studs, nuts, and washers.

Issue The staff noted that, per the safety evaluation dated February 17, 2021, the proposed alternative (referred to as relief in SLRA Section B.2.3.3) submitted pursuant to 10 CFR 50.55a(z)(1), was authorized only through the fifth 10-year ISI interval of Unit 1 and only through the fourth 10-year ISI interval of Unit 2. The staff noted that a separate alternative will need to be requested and submitted to the NRC for review and approval in order for the exception to Element 4 and staff-identified exception to Element 5 of the AMP in GALL-SLR to continue for the remainder of the subsequent period of extended operation after the fifth 10-year ISI interval of Unit 1 and after the

fourth 10-year ISI interval of Unit 2. However, the staff is not clear whether relief similar to the one described in SLRA Section B.2.3.3 will be requested and submitted to the NRC for review and approval.

Request Clarify whether a proposed alternative (referred to as relief in SLRA Section B.2.3.3) similar to the one described in SLRA Section B.2.3.3 will be requested and submitted to the NRC for review and approval in order to continue the exception to Element 4 and staff-identified exception to Element 5 of the reactor head closure stud bolting AMP in GALL-SLR described above for the remainder of the subsequent period of extended operation prior to the end date of the fifth 10-year ISI interval of Unit 1 and after the fourth 10-year ISI interval of Unit 2. If an alternative will not be submitted for prior NRC review and approval, justify the exception to Element 4 and staff-identified exception to Element 5 of the reactor head closure stud bolting AMP in GALL-SLR for the remainder of the subsequent period of extended operation after the fifth 10-year ISI interval of Unit 1 and after the fourth 10-year ISI interval of Unit 2.

RAI No. B.2.3.7-1 Regulatory Basis 10 CFR 54.21(a)(3) requires an applicant to demonstrate that the effects of aging for structures and components will be adequately managed so that the intended function(s) will be maintained consistent with the current licensing basis for the period of extended operation. One of the findings that the staff must make to issue a renewed license (10 CFR 54.29(a)) is that actions have been identified and have been or will be taken with respect to managing the effects of aging during the period of extended operation on the functionality of structures and components that have been identified to require review under 10 CFR 54.21, such that there is reasonable assurance that the activities authorized by the renewed license will continue to be conducted in accordance with the current licensing basis. To complete its review and enable the staff to make a finding under 10 CFR 54.29(a), the staff requires additional information in regard to the matters described below.

Background

In MRP-227, Revision 1-A, the EPRI MRP defines that the CSB flexure welds, LSS core support plates, and UIA fuel alignment plates in Combustion Engineering (CE)-designed pressurized water reactors (PWRs) are Primary category components for the MRP-227 basis being applied to CE-design PWR facilities. For aging management of these components, the EPRI MPR establishes the following aging management inspection and evaluation (I&E) bases for the components per the following inspection items defined in Table 4-2 of the MRP-227, Rev. 1-A report.

• Item C7 for the Primary category CSB flexure weld: Perform EVT-1 visual inspection of the weld no later than two refueling outages from the beginning of the license renewal period (with subsequent re-inspections to be performed at a 10-Year interval) if screening of the flexure weld for both fatigue and stress corrosion cracking (SCC) cannot be satisfied by plant-specific evaluation.

• Item C9 for the Primary category LSS core support plate: Perform EVT-1 visual inspection of the core support plate no later than two refueling outages from the beginning of the license renewal period (with subsequent re-inspections to be performed at a 10-Year

interval) if screening of the core support plate for fatigue cannot be satisfied by plant-specific evaluation.

• Item C9 for the Primary category UIA fuel alignment plate: Perform EVT-1 visual inspection of the fuel alignment plate no later than two refueling outages from the beginning of the license renewal period (with subsequent re-inspections to be performed at a 10-Year interval) if screening of the fuel alignment plate for fatigue cannot be satisfied by plant-specific evaluation.

Issue An information gap exists on the programmatic I&E bases for these components because neither SLRA AMP B.2.3.7 nor SLRA Appendix C provides any information on whether the screening analysis assessments for these components have been performed, and if so, how they have been performed and whether the analyses qualify as time-limited aging analyses (TLAAs) for SLRA per the TLAA definition criteria in 10 CFR 54.3(a).

Additionally, for the CSB flexure welds and LSS core support plates, the RVI gap analysis in SLRA Appendix C did not alter the Primary Inspection category bases for the CSB flexure welds from those defined for the weld type in Item C7 of Table 4-2 in MRP-227, Rev. 1-A or the Primary category bases for the LSS core support plates from those defined for the plate types in Item C9 of Table 4-2 in MRP-227, Rev. 1-A. However, based on the updated assessment for the UIA fuel alignment plates in MRP 2018-022, the gap analysis basis adjusted the inspection category for the fuel alignment plates by making the plates as Expansion inspection category components for the program (as linked to Primary EVT-1 visual inspections that will be performed on the CSB cylinder middle girth welds [MGWs]). This differs from the 60-year I&E criteria for the UIA fuel alignment plates in Item C10 of Table 4-2 in MRP-2018-022 which maintains the UIA fuel alignment plates as Primary inspection category components if the plates cannot be screened out for fatigue. If the UIA fuel alignment plates were screening out for fatigue, the fuel alignment plates would be placed in No Additional Measures [NAM] category.

Request

1. CSB flexure weld bases. Consistent with Item C7 in Table 4-2 of MRP-227, Rev. 1-A, clarify whether the CSB flexure welds are being placed in the Primary inspection category for the AMP based on plans to perform primary EVT-1 inspections of the welds during the period of extended operation or whether the CSB flexure welds are being placed in the NAM category of the program based on performance of fatigue and SCC screening analysis and acceptable screening results of those analyses. If the CSB flexure welds are being placed into the NAM category based on applicable component-specific screening results, identify the type of analyses that were performed for the fatigue and SCC screening objectives of the flexure welds in the current licensing basis (CLB). As part of this, the staff requests that the fatigue and SCC screening analysis or analyses for the flexure welds be provided for the Reactor Vessel Internals AMP. Additionally, clarify whether the applicable component-specific screening analyses for fatigue and SCC need to be identified as TLAAs for the SLRA when assessed against the six criteria for defining TLAAs in 10 CFR 54.3(a).

2. LSS core support plate bases. Consistent with Item C9 in Table 4-2 of MRP-227, Rev. 1-A, clarify whether the LSS core support plates are being placed in the Primary inspection category for the AMP based on plans to perform primary EVT-1 inspections of the plates during the period of extended operation or whether the LSS core support plates are being placed in the NAM category of the program based on performance of a fatigue

screening analysis and acceptable screening results of the analysis. If the LSS core support plates welds are being placed into the NAM category based on applicable component-specific screening results, identify the type of analysis that was performed for the fatigue screening objective of the plates in the CLB. As part of this, the staff requests that the applicable type of fatigue screening analysis for core support plates be provided for the Reactor Vessel Internals AMP. Additionally, clarify whether the applicable component-specific screening analysis for fatigue needs to be identified as TLAAs for the SLRA when assessed against the six criteria for defining TLAAs in 10 CFR 54.3(a).

3. UIA fuel alignment plate bases. Since Item C10 in Table 4-2 of MRP-227, Rev. 1-A either placed the UIA fuel alignment plates in either the NAM category or Primary inspection category of the AMP, explain and justify the change in the basis that now places the UIA fuel alignment plates in the Expansion category of the program versus the prior bases for the plates in Item C10 of Table 4-2 in the MRP-227, Rev. 1-A report. As part of this explanation, clarify if the UIA fuel alignment plates were appropriately screened out for fatigue-type cracking mechanisms for the prior 60-year programmatic basis. If a fatigue screening analysis was performed for the UIA fuel alignment plates as part of the CLB, identify the type of analysis that was performed for the fatigue screening objective of the plates. As part of this, the staff requests that the applicable type of fatigue screening analysis of the fuel alignment plates be provided for the Reactor Vessel Internals AMP. Additionally, clarify whether the applicable component-specific screening analysis for fatigue needs to be identified as TLAAs for the SLRA when assessed against the six criteria for defining TLAAs in 10 CFR 54.3(a).

RAI No. B.2.3.7-2 Regulatory Basis 10 CFR 54.21(a)(3) requires an applicant to demonstrate that the effects of aging for structures and components will be adequately managed so that the intended function(s) will be maintained consistent with the current licensing basis for the period of extended operation. One of the findings that the staff must make to issue a renewed license (10 CFR 54.29(a)) is that actions have been identified and have been or will be taken with respect to managing the effects of aging during the period of extended operation on the functionality of structures and components that have been identified to require review under 10 CFR 54.21, such that there is reasonable assurance that the activities authorized by the renewed license will continue to be conducted in accordance with the current licensing basis. To complete its review and enable the staff to make a finding under 10 CFR 54.29(a), the staff requires additional information in regard to the matters described below.

Background

SLRA Table 3.1.2-2 includes two AMR Items for the Unit 1 CSB expandable plugs and patches:

(1) a GALL-SLR-based AMR item (based on GALL-SLR AMR Item IV.B4.R-423, as updated in in NRC Interim Staff Guidance No. SLR-ISG-2021-01-PWRVI) on cracking of the plugs and patches which credits the Reactor Vessel Internals Program as the basis for aging management, and (2) a GALL-SLR-based AMR item (based on GALL-SLR AMR Item IV.B4.R-424, as updated in NRC Interim Staff Guidance No. SLR-ISG-2021-01-PWRVI) on loss of preload in the CSB expandable plugs and patches that credits the time limited aging analysis (TLAA) in SLRA Section 4.7.3 as the basis for aging management.

Issue The staff acknowledges the validity of using GALL-SLR AMR Item IV.B4.R-423 as the basis for the AMR line item on cracking of the Unit 1-specific CSB expandable plugs and patches, as given on SLRA page 3.1-61. However, since the scope of the criteria in MRP-227, Rev. 1-A do not bound or include any inspection and evaluation (I&E) criteria for these types of components, aging management for cracking of the Unit 1 CSB expandable plugs and patches should be being done on a St Lucie Unit 1 plant-specific basis. Yet the RVI gap analysis tables in SLRA Appendix C does not include any line item for the Unit 1-specific CSB expandable plugs and patches.

Request Provide the basis for why the table entries in SLRA Appendix C do not include any line item entry or entries for the St. Lucie Unit 1-specific CSB expandable plugs and patches that include(s) the following information: (1) inspection category for the components, and the corresponding Primary or Expansion category component if the CSB patches and plugs are identified as Expansion or Primary components under the program, (2) applicable aging effects or mechanisms, (3) component applicability basis, (4) examination method, frequency and coverage criteria, and (5) applicable examination Expansion criteria and examination acceptance criteria.

RAI No. B.2.3.7-3 Regulatory Basis 10 CFR 54.21(a)(3) requires an applicant to demonstrate that the effects of aging for structures and components will be adequately managed so that the intended function(s) will be maintained consistent with the current licensing basis for the period of extended operation. One of the findings that the staff must make to issue a renewed license (10 CFR 54.29(a)) is that actions have been identified and have been or will be taken with respect to managing the effects of aging during the period of extended operation on the functionality of structures and components that have been identified to require review under 10 CFR 54.21, such that there is reasonable assurance that the activities authorized by the renewed license will continue to be conducted in accordance with the current licensing basis. To complete its review and enable the staff to make a finding under 10 CFR 54.29(a), the staff requires additional information in regard to the matters described below.

Background

On pages C-7 and C-8 of the gap analysis summary in SLRA Appendix C, the applicant identifies that the following three component types are Expansion category components for the Primary category CSB lower cylinder girth welds (i.e., CSB MGWs) that will be inspected during the subsequent period of extended operation: (1) CSB middle axial welds (MAWs), (2)

CSB lower axial welds (LAWs), and (3) fuel alignment plates in the upper internals assemblies (UIAs).

Issue Per the footnotes of SLRA pages C-7 and C-8, the CSB MGWs are the lower cylinder girth welds of reference. In MRP 2018-022 (ADAMS Accession No. ML19081A061), the EPRI MRP identifies that the Primary category CSB MGWs should also link to a fourth Expansion category

component, the lower support structure (LSS) core support columns. The LSS core support columns are also reflected as Expansion category components for the CSB MGWs in the newly submitted MRP-227, Revision 2 report. However, pages C-7 and C-8 in SLRA Appendix C do not cite or identify that the LSS core support columns are Expansion category components for the CSB lower cylinder girth welds (i.e., in addition to the CSB MAWs and LAWs, and the UIA fuel alignment plates as being Expansion category components for the CSB MGWs).

Request Provide the basis why the tabular line items and associated footnotes for CSB lower cylinder girth welds in SLRA Appendix C (i.e., on SLRA pages C-7 and C-8) only cite the lower cylinder axial welds (i.e., the CSB MAWs and LAWs as explained in the tabular footnote) and the UIA fuel alignment plate as the Expansion Link(s) components for the CSB lower cylinder girth welds (i.e., for the CSB MGWs) and do not identify the LSS core support columns as a fourth Expansion category component type for the Primary category CSB lower cylinder girth welds.

Additionally, provide the basis why the Expansion Criteria column entry of the line item for the CSB lower cylinder girth welds on SLRA page C-8 does not include any expansion criteria for the LSS core support columns and why the Expansion Item Examination Acceptance Criteria column entry of the same line item on SLRA page C-8 does not specifically define the relevant conditions for fuel alignment plates or LSS core support columns.

RAI B.2.2.1-1 Regulatory Basis 10 CFR 54.21(a)(3) requires an applicant to demonstrate that the effects of aging for structures and components will be adequately managed so that the intended function(s) will be maintained consistent with the current licensing basis for the period of extended operation. One finding that the staff must make to issue a renewed license (10 CFR 54.29(a)) is that actions have been identified and have been or will be taken with respect to managing the effects of aging during the period of extended operation on the functionality of structures and components that have been identified to require review under 10 CFR 54.21, such that there is reasonable assurance that the activities authorized by the renewed license will continue to be conducted in accordance with the current licensing basis. In order to complete its review and enable making a finding under 10 CFR 54.29(a), the staff requires additional information in regard to the matters described below.

Background

The monitoring and trending program element of GALL-SLR Report AMP X.M1, Fatigue Monitoring Program, indicates that the program provides for revisions to the fatigue analyses or other corrective actions (e.g., revising augmented inspection frequencies) on an as-needed basis if the values assumed for fatigue parameters are approached or transient counts exceed the design or assumed quantities.

SLRA Section B.2.3.44 addresses the ASME Code,Section XI, Appendix L flaw tolerance analysis for the pressurizer surge line. The section indicates that the projected 80-year fatigue cycles, as opposed to the design cycles, were used to establish an estimate of the average

number of cycles per year for calculating fatigue crack growth. Specifically, the following reference describes the 80-year projected transient cycles that are assumed in the flaw tolerance analysis (

Reference:

Table 1 of Structural Integrity Report No. 2001262.401, Revision 1, Flaw Tolerance Evaluation of St. Lucie Units 1 and 2 Surge Line Using ASME Code,Section XI, Appendix L for Subsequent License Renewal).

Issue SLRA Section B.2.2.1 addresses the Fatigue Monitoring Program. However, the SLRA section does not clearly describe whether the Fatigue Monitoring Program will monitor the transient cycles, which are assumed in the Appendix L analysis for the pressurizer surge line, to ensure that the actual cycles do not exceed the assumed transient cycles.

Request Clarify whether the Fatigue Monitoring Program will monitor the transient cycles, which are assumed in the Appendix L flaw tolerance analysis for the pressurizer surge line, to ensure the validity of the cycles that are used in the flaw tolerance analysis. If some of the transients are not monitored for cycle counting, explain why cycle monitoring is not needed for those transients (e.g., demonstration of conservatism associated with the transient cycles assumed in the flaw tolerance analysis compared to the estimated 80-year cycles representing actual cycles).

RAI B.2.3.44-1 Regulatory Basis 10 CFR 54.21(a)(3) requires an applicant to demonstrate that the effects of aging for structures and components will be adequately managed so that the intended function(s) will be maintained consistent with the current licensing basis for the period of extended operation. One finding that the staff must make to issue a renewed license (10 CFR 54.29(a)) is that actions have been identified and have been or will be taken with respect to managing the effects of aging during the period of extended operation on the functionality of structures and components that have been identified to require review under 10 CFR 54.21, such that there is reasonable assurance that the activities authorized by the renewed license will continue to be conducted in accordance with the current licensing basis. In order to complete its review and enable making a finding under 10 CFR 54.29(a), the staff requires additional information in regard to the matters described below.

Background

SLR Section B.2.3.44 addresses the Pressurizer Surge Line Program that is a plant-specific program for 80 years of operation.

Issue SLRA Section B.2.3.44 provides the overall program description and operating experience program element of the Pressurizer Surge Line Program. However, SLRA Section B.2.3.44 does not clearly describe the other program elements of the Pressurizer Surge Line Program even though this program is a plant-specific program that is not generically described in the GALL-SLR report.

Request Provide the program elements of the Pressurizer Surge Line Program other than the operating experience program element, consistent with SLR-SRP Section A.1.2.3, Aging Management Program Elements.

RAI 4.3.1-1 Regulatory Basis Pursuant to 10 CFR 54.21(c), the SLRA must include an evaluation of time-limited aging analyses (TLAAs). The applicant must demonstrate that (i) the analyses remain valid for the period of extended operation, (ii) the analyses have been projected to the end of the period of extended operation, or (iii) the effects of aging on the intended function(s) will be adequately managed for the period of extended operation.

Background

SLRA Tables 4.3.1-1 and 4.3.1-2 describe the design transients for St. Lucies Units 1 and 2 respectively, which were included in the original license renewal application (60-year operation).

These tables indicate that some transients will not be monitored in the Fatigue Monitoring Program (e.g., plant loading, 5 percent/minute and 10 percent step load increase transients).

In addition, Tables 1 and 2 of Westinghouse LTR-SDA-II-20-32-NP indicate that the transients, which will not be monitored in the Fatigue Monitoring Program, are consistent with the transients that are not monitored in the current licensing basis (i.e., 60-year operation). The tables explain that these design transients were excluded from the monitoring of the Fatigue Monitoring Program because the transients resulted in a fatigue usage less than 0.1 or large margins were present with respect to actual cycle counts compared to allowable cycle limits.

Issue Confirmation is needed that the basis of excluding these transients from cycle counting is valid for 80 years of operation.

Request

1. For the transients excluded from cycle counting based on cycle margins, describe the estimated 80-year cycles in comparison with the design cycles to confirm that cycle margins between the estimated 80-year cycles and the design cycles are large enough to exclude the transients from cycle counting.

2. For the transients excluded from cycle counting based on fatigue usage contributions, clarify whether the 80-year evaluation considers all the contributions of the excluded transients on cumulative fatigue usage to confirm that the total contributions of the transients for an applicable location do not exceed the contribution limit (0.1), as opposed to a single contribution of a specific transient. If not, justify why the combined effects of the transients on fatigue usage are not considered in the determination for fatigue monitoring exclusion.

RAI 4.3.1-2 Regulatory Basis Pursuant to 10 CFR 54.21(c), the SLRA must include an evaluation of time-limited aging analyses (TLAAs). The applicant must demonstrate that (i) the analyses remain valid for the period of extended operation, (ii) the analyses have been projected to the end of the period of extended operation, or (iii) the effects of aging on the intended function(s) will be adequately managed for the period of extended operation.

Background

SLRA Tables 4.3.1-1 and 4.3.1-2 describe the 80-year projected cycles for the design transients of St. Lucie Units 1 and 2 respectively, which were included in the original license renewal application (60-year operation). These tables do not include the bolt-up transient for the reactor vessel. In comparison, the following reference evaluates the design basis thermal cycle events for the current licensing basis (

Reference:

SIR-01-102, Revision 3, Thermal Cycle Evaluation for St. Lucie Units 1 and 2). Accordingly, this reference includes the bolt-up transient as a design transient. The SIR-01-102 report also indicates that the bolt-up transient is excluded from cycle counting based on a large cycle margin in the current licensing basis (60 years of operation).

Issue Clarification needed related to why SLRA Tables 4.3.1-1 and 4.3.1-2 do not identify the bolt-up transient as a design transient in contrast with the SIR-01-102 report. The staff also found a need to clarify the basis of excluding this transient from cycle counting for 80-year operation.

Request

1. Explain why SLRA Tables 4.3.1-1 and 4.3.1-2 do not identify the bolt-up transients as a design transient in contrast with the SIR-01-102 report. If the omission of the transient cannot be justified, revise the SLRA to identify the bolt-up transient as a design transient related to the cycle projections.

2. If the bolt-up transient is excluded from fatigue monitoring based on a large cycle margin, describe the estimated 80-year cycles of the bolt-up transient in comparison with the design cycles for each St. Lucie unit to confirm the large cycle margin.

RAI 4.3.1-3 Regulatory Basis Pursuant to 10 CFR 54.21(c), the SLRA must include an evaluation of time-limited aging analyses (TLAAs). The applicant must demonstrate that (i) the analyses remain valid for the period of extended operation, (ii) the analyses have been projected to the end of the period of extended operation, or (iii) the effects of aging on the intended function(s) will be adequately managed for the period of extended operation.

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Background===

SLRA Section 4.3.1 states that the transients, which are included in the current Fatigue Monitoring Program but were not included in the original St. Lucie license renewal application, are presented in Tables 4.3.1-3 and 4.3.1-4 for St. Lucie Units 1 and 2 respectively. In addition, SLRA Tables 4.3.1-5 and 4.3.1-6 describe the 80-year projections for additional transients (e.g.,

loss of letdown flow transient cycles) that subsequent license renewal fatigue evaluations for St. Lucie Units 1 and 2 respectively.

Issue However, the SLRA does not clearly discuss whether the Fatigue Monitoring Program will monitor the additional transients for 80-year operation that are described in SLRA Tables 4.3.1-5 and 4.3.1-6. The staff found a need to clarify whether these additional cycles will be monitored in the Fatigue Monitoring Program.

SLRA Table 4.3.1-4 also addresses the pressurizer spray nozzle cumulative usage factor in the column for the additional Unit 2 transients that are included in the fatigue monitoring. This item does not clearly describe relevant transients and their cycle limits, accumulated cycles and 80-year projected cycles. The staff found a need to clarify the transients and associated cycles for this item.

Request

1. Clarify whether the Fatigue Monitoring Program will monitor the additional transients that are described in SLRA Tables 4.3.1-5 and 4.3.1-6. If not, explain why the additional transients do not need to be monitored in the Fatigue Monitoring Program.

2. With respect to the pressurizer spray nozzle cumulative usage factor addressed in SLRA Table 4.3.1-4, describe the relevant transients and their cycle limits, accumulated cycles and 80-year projected cycles, consistent with the other transient listings in the table.

RAI 4.3.2-1 Regulatory Basis Pursuant to 10 CFR 54.21(c), the SLRA must include an evaluation of time-limited aging analyses (TLAAs). The applicant must demonstrate that (i) the analyses remain valid for the period of extended operation, (ii) the analyses have been projected to the end of the period of extended operation, or (iii) the effects of aging on the intended function(s) will be adequately managed for the period of extended operation.

Background

SLRA Section 4.3.2 addresses the implicit fatigue analysis and the associated 80-year cycle projections for non-Class 1 piping systems. Specifically, SLRA Table 4.3.2-2 indicates that the hot-leg sample line is subject to approximately 29,200 cycles for 80 years of operation.

Therefore, the relevant stress range reduction factor for the sample line is 0.7, which corresponds to thermal cycles up to 45,000.

Issue However, the SLRA does not clearly discuss how the stress analysis for the sample line with the stress reduction factor (0.7) less than 1.0 meets a relevant acceptance criterion.

Request Clarify whether the thermal expansion stress (SE) of the sample line meets the acceptance criteria of the stress analysis for each unit of the St. Lucie plant (e.g., the stress does not exceed the allowable stress range (SA), as modified by applying the stress reduction factor of 0.7 for the piping). If not, provide justification for why the applicants stress analysis results with the stress reduction factor less than 1.0 are acceptable, including relevant references (e.g.,

edition and provisions of a code).

RAI 4.3.2-2 Regulatory Basis Pursuant to 10 CFR 54.21(c), the SLRA must include an evaluation of time-limited aging analyses (TLAAs). The applicant must demonstrate that (i) the analyses remain valid for the period of extended operation, (ii) the analyses have been projected to the end of the period of extended operation, or (iii) the effects of aging on the intended function(s) will be adequately managed for the period of extended operation.

Background

SLRA Section 4.3.2 addresses the implicit fatigue analysis and the associated 80-year cycle projections for non-Class 1 piping systems. In addition, SLRA Appendix A1, Section 19.3.3.2 and Appendix A2, Section 19.3.3.2 provide the UFSAR supplement summarizing the implicit fatigue analysis for St. Lucie Units 1 and 2, respectively.

Issue The fatigue analysis in SLRA Section 4.3.2 is based on the 80-year cycle projections. However, SLRA Section 4.3.2 refers to the TLAA dispositions in accordance with both 10 CFR 54.21(c)(i),

which indicates that the TLAA remains valid, and 10 CFR 54.21(c)(ii), which indicates that the TLAA has been projected. The same TLAA dispositions are listed in SLRA Table 4.1.5-3. In contrast, the UFSAR supplement descriptions in SLRA Appendix A1, Section 19.3.3.2 and Appendix A2, Section 19.3.3.2 refer to only the TLAA disposition in accordance with 10 CFR 54.21(c)(i).

Request Explain why SLRA Section 4.3.2 includes the TLAA disposition per 10 CFR 54.21(c)(i) even though the TLAA is based on the 80-year cycle projections. In addition, resolve the inconsistency among the TLAA dispositions described in SLRA Section 4.3.2, SLRA Table 4.1.5-3 and UFSAR summary descriptions (SLRA Appendix A1, Section 19.3.3.2 and Appendix A2, Section 19.3.3.2).

RAI 4.3.3-1 Regulatory Basis Pursuant to 10 CFR 54.21(c), the SLRA must include an evaluation of time-limited aging analyses (TLAAs). The applicant must demonstrate that (i) the analyses remain valid for the period of extended operation, (ii) the analyses have been projected to the end of the period of extended operation, or (iii) the effects of aging on the intended function(s) will be adequately managed for the period of extended operation.

Background

SLRA Section 4.3.3 addresses the TLAA on the environmentally assisted fatigue (EAF) for reactor coolant pressure boundary components and piping. In relation to the EAF, SLRA Tables 3-1 and 3-2 provide the leading EAF locations (also called sentinel locations) for equipment and piping, respectively (

Reference:

Westinghouse Report LTR-SDA-II-20-31-NP, Revision 2, St.

Lucie Units 1 & 2 Subsequent License Renewal: Primary Equipment and Piping Environmentally Assisted Fatigue Evaluations).

Issue SLRA Section 4.3.3 does not clearly describe the approach for the EAF screening evaluation that was used to determine the leading EAF locations.

Request Describe the approach for EAF screening evaluation to determine the leading EAF locations.

As part of the response, clarify the following: (1) whether the EAF screening evaluation calculates the environmental fatigue correction factor (Fen) and environmental fatigue usage factor (CUFen) values in accordance with NUREG/CR-6909, Revision 1; (2) the criteria and their basis used to determine the leading EAF locations; (3) whether the leading EAF locations are determined based on the CUFen values in each piping system or zone that is exposed to essentially the same thermal and pressure transients; and (4) whether the EAF screening is performed for each material of fabrication (e.g., carbon steel, stainless steel and nickel alloy).

RAI 4.3.3-2 Regulatory Basis Pursuant to 10 CFR 54.21(c), the SLRA must include an evaluation of time-limited aging analyses (TLAAs). The applicant must demonstrate that (i) the analyses remain valid for the period of extended operation, (ii) the analyses have been projected to the end of the period of extended operation, or (iii) the effects of aging on the intended function(s) will be adequately managed for the period of extended operation.

Background

The Framatome 86-9329644-001 report summarizes the environmentally-assisted fatigue (EAF) analysis for St. Lucie Unit 2 replacement steam generators, Unit 1 and 2 replacement reactor vessel closure heads, Unit 2 pressurizer repairs, Unit 2 weld overlays and Unit 2 auxiliary spray

line reducer (

Reference:

Framatome Document Number 86-9329644-001, St. Lucie SLR CUFen Evaluations Summary, July 15, 2021).

Table 5-2 of the Framatome report specifies the reduced cycles of the transients that are used in the environmental cumulative usage factor (CUFen) calculations, as reduced from the design cycles. Some of these transients, which involve reduced (limited) cycles compared to design cycles, will not be monitored in the Fatigue Monitoring Program, as indicated in SLRA Section 4.3.1.

The transients, which are used for the CUFen calculations in the Framatome report and will not be monitored in the Fatigue Monitoring Program, are the following: (1) plant loading/unloading transient; (2) 10 percent step load increase/decrease transient; and (3) cold feedwater following hot standby transient.

Issue Given that these transients and their reduced cycles are used for the CUFen calculations in the Framatome report, the staff found a need to confirm the adequacy of excluding these transients form fatigue monitoring.

The staff also noted that the primary coolant pump starting/stopping transient (also designated as the DP transient) is used in the EAF analysis for the Unit 2 steam generator tube-to-tubesheet weld. However, SLRA Section 4.3.1 and Framatome report do not clearly address whether the pump transient for St. Lucie Unit 2 will be monitored in the Fatigue Monitoring Program.

In addition, SLRA Section 4.3.1 and Framatome report Tables 5-2 and 5-3 address pressurizer spray nozzle transients. However the SLRA and Framatome report do not clearly describe whether the following transients related to Unit 2 pressurizers, which involve reduced cycles in the CUFen calculations, will be monitored in the Fatigue Monitoring Program: (1) spray nozzle transient (also called the spray nozzle transient 17A/B/C); (2) main spray initiation transient; (3) auxiliary spray at power 1 and auxiliary spray at power 2 transients; and (4) main spray term in cooldown transient.

Request

1. Provide justification for excluding the plant loading/unloading, 10 percent step load increase/decrease, and cold feedwater following hot standby transients from fatigue monitoring even though these transients and associated reduced cycles are used in the EAF analysis of the Framatome report. If these transients are excluded from fatigue monitoring based on a large cycle margin, provide the 80-year cycle estimate in comparison with the design cycle for each transient to confirm that the 80-year cycle estimate is sufficiently less than the design cycle with a large cycle margin. If the absence of load follow operations is the basis for excluding some of these transients from fatigue monitoring, identify those transients as part of the response.

2. Clarify whether the primary coolant pump starting/stopping transient of St. Lucie Unit 2 will be monitored in the Fatigue Monitoring Program. If not, provide justification for excluding

the transient from fatigue monitoring. If this transient is excluded from fatigue monitoring based on a large cycle margin, provide the 80-year cycle estimate in comparison with the design cycle to confirm that the 80-year cycle estimate is sufficiently less than the design cycle with a large cycle margin.

3. Clarify whether the spray nozzle, main spray initiation, auxiliary spray at power 1, auxiliary spray at power 2, and main spray term in cooldown transients will be monitored in the Fatigue Monitoring Program to ensure that the actual transient cycles do not exceed the cycles projected and analyzed in the EAF analysis of the Framatome report. If not, provide justification for excluding these transients from fatigue monitoring. If these transients are excluded from fatigue monitoring based on a large cycle margin, provide the 80-year cycle estimate in comparison with the design cycle for each transient to confirm that the 80-year cycle estimate is sufficiently less than the design cycle with a large cycle margin.

RAI 4.3.4-1 Regulatory Basis Pursuant to 10 CFR 54.21(c), the SLRA must include an evaluation of time-limited aging analyses (TLAAs). The applicant must demonstrate that (i) the analyses remain valid for the period of extended operation, (ii) the analyses have been projected to the end of the period of extended operation, or (iii) the effects of aging on the intended function(s) will be adequately managed for the period of extended operation.

Background

SLRA Section 4.3.4 addresses the high-energy line break (HELB) analyses. SLRA Section 4.3.4 also explains that, as discussed in SLRA Section 4.3.1 and Table 4.3.1-2, the original Unit 2 design cycles (CLB cycles) bound the projected cycles for 80 years of operation. In comparison, if a cumulative usage factor (CUF) value is greater than 0.1, such locations are postulated as break locations in the HELB analysis. This CUF threshold for HELB postulation (0.1) is significantly lower than the CUF limit of 1.0 specified in fatigue design analyses.

Issue The applicant did not clearly address whether the 80-year operation may increase the CUF values at the Unit 2 Class 1 piping locations above the CUF threshold of 0.1 for HELB postulation such that additional break locations needs to be evaluated in the HELB analysis.

For example, SLRA Section 4.3.1 indicates that the design cycles of the loss of letdown flow transient is increased from 50 cycles to 500 cycles for the subsequent period of extended operation (SPEO). Based on this cycle increase for the SPEO and the existing CUF threshold for HELB location postulation (0.1), the applicant may need to identify additional HELB locations. The staff also noted a possibility that the identification of additional HELB locations may be needed due to the increases in actual transient cycles during the SPEO.

Therefore, the staff found a need to confirm that, if new additional piping break locations are identified based on the CUF threshold of 0.1, the applicant will evaluate such new break locations in the HELB analysis. The staff also found a need to clarify the activities of the Fatigue Monitoring Program (SLRA Section B.2.2.1) related to the HELB TLAA.

Request

1. Clarify whether additional break locations and their effects will be evaluated in the Class 1 piping HELB analysis if new additional piping break locations are identified based on the CUF threshold of 0.1 during the SPEO. If not, provide justification for why such additional HELB locations do not need to be evaluated in the HELB analysis.

2. The applicant proposed to use the Fatigue Monitoring Program for managing the aging effect associated with the HELB TLAA, as addressed in SLRA Section 4.3.4 and Enhancement 5 of the program (SLRA Section B.2.2.1). In relation to the program enhancement, clarify (1) whether the program will use the CUF threshold of 0.1 as an acceptance criterion for HELB location postulations, consistent with SLRA Section 4.3.4 and (2) whether the program will take a relevant action to update the HELB analysis as needed based on potentially new additional HELB locations for 80 years of operation.

RAI 4.7.8-1 Regulatory Basis Title 10 of the Code of Federal Regulations (CFR) Section 54.21(a)(1) requires license renewal applicants to perform an integrated plant assessment (IPA) and their application to identify and list systems, structures, and components (SSCs) that are within the scope of license renewal and subject to aging management review (AMR). Further, 10 CFR 54.21(a)(3) requires, for the SSCs identified to be subject to AMR, the applicant demonstrate that the effects of aging will be adequately managed such that their intended functions are maintained consistent with the current licensing basis (CLB) for the subsequent period of extended operation. To complete its review and enable the staff to make a reasonable assurance finding on functionality of reviewed SSCs for the subsequent period of extended operation consistent with 10 CFR 54.21, the staff requires under 10 CFR 54.29(a) additional information be provided regarding the matters described below.

Background

Under Section 2.4 PWSCC Crack Growth Mechanisms of the Framatome proprietary Document No. 86-9329645-000 (Reference 4.8.46), the PWSCC crack growth rate for Alloy 52M that the applicant used in the TLAA calculations is provided. The NRC has not endorsed this crack growth rate and is currently reviewing its adequacy.

Issue The crack growth rate is a key factor in the evaluation provided in this TLAA and could have an impact on the overall conclusion to address the TLAA for Port St. Lucie (PSL) Units 1 and 2.

PSL Units 1 and 2 structural weld overlays (SWOLs) are examined in accordance with ASME Code Case N-770-5 (Reference 4.8.47). Code Case N-770-5 requires SWOL welds to be examined at a frequency defined by Table 1 and Note 10. Note 10 states, in part, Those welds not included in the 25% sample shall be examined prior to the end of the mitigation evaluation period if the plant is to be operated beyond that time. The calculations of this TLAA would establish the scope of welds to be examined within the extended period of operation as well as the examination timeline.

Request

1. If the NRC, at a future date, endorses a different crack growth rate than that used by the applicant, what actions would the applicant take to address the revised rate?

2. Where is this process documented in the applicants procedures?

RAI B.2.3.27-1 Regulatory Basis 10 CFR 54.21(a)(3) requires an applicant to demonstrate that the effects of aging for structures and components will be adequately managed so that the intended function(s) will be maintained consistent with the current licensing basis for the period of extended operation. One of the findings that the staff must make to issue a renewed license (10 CFR 54.29(a)) is that actions have been identified and have been or will be taken with respect to managing the effects of aging during the period of extended operation on the functionality of structures and components that have been identified to require review under 10 CFR 54.21, such that there is reasonable assurance that the activities authorized by the renewed license will continue to be conducted in accordance with the current licensing basis. In order to complete its review and enable the staff to make a finding under 10 CFR 54.29(a), the staff requires additional information in regard to the matters described below.

Background

GALL-SLR Report Table XI.M41-1, Preventive Actions for Buried and Underground Piping and Tanks, recommends that the following are externally coated in accordance with the preventive actions program element of GALL-SLR Report AMP XI.M41: (a) buried metallic piping; and (b) underground steel piping.

During its audit, the staff reviewed the St. Lucie Nuclear Plant Asset Management Plan for the Underground Piping and Tanks Integrity Program and noted that a coating material of none is identified for several material/system combinations. For example, the staff noted that the following have none as the coating material: (a) safety-related stainless steel piping in the diesel fuel oil and auxiliary feedwater sub-systems; and (b) safety-related carbon steel piping in the diesel fuel oil sub-system.

During its review of the Updated Final Safety Analysis Report (UFSAR) for Unit 2 (ADAMS Accession No. ML20268A114), the staff noted the following: (a) the two inch piping run between the diesel oil storage tank and the day tanks is encased within a three inch guard pipe; and (b) the guard pipe is coated with a corrosion resistant coating.

By letter dated April 7, 2022 (ADAMS Accession No. ML22097A202), the applicant clarified the following: (a) there is approximately 890 feet of fuel oil piping housed within guard piping; and (b) the guard pipe prevents contact of the fuel oil piping with the soil environment.

Issue Based on its observations noted above, the staff seeks clarification on whether the following are coated in accordance with the preventive actions program element of GALL-SLR Report AMP XI.M41: (a) buried metallic piping; and (b) underground steel piping. With respect to the fuel oil piping housed within guard piping, the staff notes that the UFSAR specifies portions of guard piping are provided with a corrosion resistant coating. However, the staff seeks clarification with respect to the following: (a) if this coating is provided for the 890 ft of guard

piping referenced in the April 7, 2022, supplement; and (b) if the corrosion resistant coating is consistent with the coating types identified in the preventive actions program element of GALL-SLR Report AMP XI.M41 (e.g., coal tar enamel).

Request Provide clarification regarding if the following are coated in accordance with the preventive actions program element of GALL-SLR Report Table XI.M41-1: (a) buried metallic piping (including exterior surfaces of guard piping exposed to soil); and (b) underground steel piping. If all or portions of in-scope piping and piping components are not externally coated in accordance with the preventive actions program element of GALL-SLR Report AMP XI.M41, provide justification for why external coatings are not provided.

RAI 19.2.2.17-1 Regulatory Basis 10 CFR 54.21(a)(3) requires an applicant to demonstrate that the effects of aging for structures and components will be adequately managed so that the intended function(s) will be maintained consistent with the current licensing basis for the period of extended operation. One of the findings that the staff must make to issue a renewed license (10 CFR 54.29(a)) is that actions have been identified and have been or will be taken with respect to managing the effects of aging during the period of extended operation on the functionality of structures and components that have been identified to require review under 10 CFR 54.21, such that there is reasonable assurance that the activities authorized by the renewed license will continue to be conducted in accordance with the current licensing basis. 10 CFR 54.21(d) requires each license renewal application to include a final safety analysis report (FSAR) supplement, containing a summary description of the programs and activities for managing the effects of aging. To complete its review and enable the staff to make a finding under 10 CFR 54.29(a), the staff requires additional information in regard to the matters described below.

Background

In its discussions about FSAR supplements, the Standard Review Plan for Subsequent License Renewal (NUREG-2192) notes that the description should be sufficiently comprehensive such that later changes to the program can be controlled by 10 CFR 50.59. NUREG-2192 also notes that the Generic Aging Lessons Learned for Subsequent License Renewal (GALL-SLR) Report (NUREG-2191), Table XI-01 provides examples of the type of information to be included.

GALL-SLR Report, Table XI-01, FSAR Supplement Summaries for GALL-SLR Report Chapter XI Aging Management Programs [AMP], provides a description of the Outdoor and Large Atmospheric Metallic Storage Tanks program (AMP XI.M29), stating that loss of material is managed by conducting periodic internal and external visual examinations.

SLRA Section B.2.3.17, Outdoor and Large Atmospheric Metallic Storage Tanks program operating experience (OE), states that in April 2011, the U1 RWT caulking inspection had not been performed on time. An extent of condition was performed and revealed that a weekly report on project preventive maintenance activities had not been performed.

During the on-site audit, Action Report 02412714(AR) was submitted to the corrective action program which states, While performing a walkdown with NRC, noted that tank base flange to concrete caulking requires repair/replacement.

Issue The Updated Final Safety Analysis Report (UFSAR) supplement for the Outdoor and Large Atmospheric Metallic Storage Tanks program appears to lack a sufficient description of the activities (inspection frequency) that will be used for inspection of caulking or sealant based on the above OE.

Request Regarding SLRA Section 19.2.2.17 detailing UFSAR changes: a) provide additional information that explains how the current description of the program and aging management activities in the UFSAR supplement meets the intent of 10 CFR 54.21(d), and NUREG-2192 which states that the description should be sufficiently comprehensive such that later changes to the program can be controlled by 10 CFR 50.59 or b) modify the UFSAR supplement to include the inspection frequency that will be used for inspection of caulking or sealant on the in-scope tanks in the Outdoor and Large Atmospheric Metallic Storage Tanks program.

B.2.3.21-1 Regulatory Basis 10 CFR 54.21(a)(3) requires an applicant to demonstrate that the effects of aging for structures and components will be adequately managed so that the intended function(s) will be maintained consistent with the current licensing basis for the period of extended operation. One of the findings that the staff must make to issue a renewed license (10 CFR 54.29(a)) is that actions have been identified and have been or will be taken with respect to managing the effects of aging during the period of extended operation on the functionality of structures and components that have been identified to require review under 10 CFR 54.21, such that there is reasonable assurance that the activities authorized by the renewed license will continue to be conducted in accordance with the current licensing basis. In order to complete its review and to make a finding under 10 CFR 54.29(a), the staff requires additional information in regard to the matters described below.

Background

SLRA Table 3.3.2-6, Fire Protection / Service Water - Summary of Aging Management Evaluation, states that loss of material due to selective leaching for gray cast iron piping exposed to soil will be managed by the Selective Leaching program.

SLRA Section B.2.3.21, Selective Leaching, states the following:

For raw water, waste water, and soil environments, the AMP includes opportunistic and periodic visual inspections of selected components that are susceptible to selective leaching, coupled with mechanical examination techniques. Destructive examinations of components to determine the presence of and depth of dealloying through-wall thickness are also conducted.

The plant specific operating experience summary in SLRA Section B.2.3.21 describes the results of one cast iron fire protection system piping inspection.

NUREG-2222, Disposition of Public Comments on the Draft Subsequent License Renewal Guidance Documents NUREG-2191 and NUREG-2192, states the following regarding the staffs basis for reducing the extent of inspections for selective leaching during the subsequent period of extended operation (i.e., 3 percent with a maximum of 10 components per GALL-SLR guidance) when compared to the extent of inspections for selective leaching during the initial period of extended operation (i.e., 20 percent with a maximum of 25 components per GALL Report, Revision 2 guidance):

1. Opportunistic inspections will be conducted throughout the period of extended operation whenever components are opened, buried, or submerged surfaces are exposed, whereas opportunistic inspections were not recommended in the previous version of AMP XI.M33;

2. Destructive examinations provide a more effective means to detect and quantify loss of material due to selective leaching;

3. The slow growing nature of selective leaching generally coupled with the inspections conducted prior to the initial period of extended operation [emphasis added by the staff]

provides insights into the extent of loss of material due to selective leaching that can be used in the subsequent period of extended operation;

4. The staffs review of many license renewal applications has not revealed any instances where loss of intended function has occurred due to selective leaching;

5. The staffs review of industry OE [operating experience] has not detected any instances of loss of material due to selective leaching, which resulted in a loss of intended function for the component; and

6. Regional inspector input (provided based on IP 71003, Post-Approval Site Inspection for License Renewal,) that selective leaching has been noted during visual and destructive inspections; however, no instances have been identified where there was the potential for loss of intended function.

The NRC issued Information Notice (IN) 2020-04, Operating Experience Regarding Failure of Buried Fire Protection Main Yard Piping, to inform the industry of OE involving the loss of function of buried gray cast iron fire water main yard piping due to multiple factors, including graphitic corrosion (i.e., selective leaching), overpressurization, low-cycle fatigue, and surface loads. As noted in the IN, a contributing cause to the failures of buried gray cast iron piping at Surry Power Station (SPS) was the external reduction in wall thickness at several locations due to graphitic corrosion.

Issue The recommended extent of inspections in GALL-SLR AMP XI.M33 are based on the six conditions noted by the staff in NUREG-2222. The staffs comparison of these six conditions to the Selective Leaching program at St. Lucie Nuclear Plant (PSL) follows:

• Based on its review of SLRA Section B.2.3.21, the staff notes that opportunistic inspections and destructive examinations for selective leaching will be performed, consistent with the first and second conditions in NUREG-2222.

• Based on its review of plant-specific operating experience in SLRA Section B.2.3.21, one selective leaching inspection has been conducted for gray cast iron piping. Based on this observation (i.e., multiple inspections for buried gray cast iron piping may not

have been performed prior to the initial period of extended operation), the third condition in NUREG-2222 may not be met at PSL for gray cast iron piping exposed to soil.

• The fourth, fifth, and sixth conditions in NUREG-2222 focus on the staffs review of industry OE not identifying any instances of loss of material due to selective leaching which had resulted in a loss of intended function for the component. Based on recent industry OE at SPS (as documented in IN-2020-04), the last three conditions in NUREG-2222 are no longer applicable for gray cast iron piping exposed to soil. Since these conditions are no longer applicable (i.e., there is now industry OE involving loss of material due to selective leaching which resulted in a loss of intended function for gray cast iron piping exposed to soil), the staff requires additional information to determine if the reduced extent of inspections in GALL-SLR AMP XI.M33 are appropriate for this material and environment combination.

Request Provide additional OE (or other technical justification) to demonstrate that the extent of inspections in GALL-SLR AMP XI.M33 (i.e., 3 percent with a maximum of 10 components) are appropriate for gray cast iron piping exposed to soil.

RAI B.2.3.21-2 10 CFR 54.21(a)(3) requires an applicant to demonstrate that the effects of aging for structures and components will be adequately managed so that the intended function(s) will be maintained consistent with the current licensing basis for the period of extended operation. One of the findings that the staff must make to issue a renewed license (10 CFR 54.29(a)) is that actions have been identified and have been or will be taken with respect to managing the effects of aging during the period of extended operation on the functionality of structures and components that have been identified to require review under 10 CFR 54.21, such that there is reasonable assurance that the activities authorized by the renewed license will continue to be conducted in accordance with the current licensing basis. In order to complete its review and to make a finding under 10 CFR 54.29(a), the staff requires additional information in regard to the matters described below.

Background

UFSAR Section 19.2.2.21, Selective Leaching, states [w]here the sample size is not based on the percentage of the population and the inspections will be conducted periodically (not one-time inspections), a reduction in the total number of inspections is acceptable as follows.

Eight visual and mechanical inspections (reduced from 10 visual and mechanical inspections) and two destructive examinations will be conducted GALL-SLR Report AMP XI.M33 states the following:

For multi-unit sites where the sample size is not based on the percentage of the population and the inspections are conducted periodically (not one-time inspections), it is acceptable to reduce the total number of inspections at the site as follows. For two unit sites, eight visual and mechanical inspections and two destructive examinations are conducted at each unit[i]n order to conduct the reduced number of inspections, the applicant states in the SLRA the basis for why the operating conditions at each unit are similar enough (e.g., flowrate, chemistry, temperature, excursions) to provide representative inspection results.

SLRA Section B.2.3.27, Buried and Underground Piping and Tanks, states the following:

[d]uring excavations, many soil samples have been obtained and analyzed. In general, the pH at PSL is approximately 9.0 indicating an alkaline soil environment. Resistivity of samples typically range from 1700 to 5000 ohm-cm. Due to the consistency of soil samples, future soil sampling was determined to not be warranted.

GALL-SLR Report Table XI.M41-2, Inspection of Buried and Underground Piping and Tanks, states soil is tested for soil resistivity, corrosion accelerating bacteria, pH, moisture, chlorides, sulfates, and redox potential.

Issue The staff requests additional information with respect to how the soil environment is consistent between both units. The SLRA does provide some discussion on soil testing; however, the staff notes that details such as the number of soil samples taken and proximity of these soil samples with respect to in-scope buried piping susceptible to selective leaching are not provided. The staff also notes that in addition to pH and soil resistivity, GALL-SLR Report Table XI.M41-2 recommends that soil is tested for corrosion accelerating bacteria, moisture, chlorides, sulfates, and redox potential.

Request Provide additional information demonstrating how the soil environment is consistent between both units. Alternatively, revise the SLRA as appropriate to reflect that the multi-unit site sample size reduction will not be used for components exposed to a soil environment.

RAI B.2.3.23 Regulatory Basis 10 CFR 54.21(a)(3) requires an applicant to demonstrate that the effects of aging for structures and components will be adequately managed so that the intended function(s) will be maintained consistent with the current licensing basis for the period of extended operation. One finding that the staff must make to issue a renewed license (10 CFR 54.29(a)) is that actions have been identified and have been or will be taken with respect to managing the effects of aging during the period of extended operation on the functionality of structures and components that have been identified to require review under 10 CFR 54.21, such that there is reasonable assurance that the activities authorized by the renewed license will continue to be conducted in accordance with the current licensing basis. In order to complete its review and enable making a finding under 10 CFR 54.29(a), the staff requires additional information in regard to the matters described below.

Background

In the program basis document (NEESL00008-REPT-067), Subsequent License Renewal Aging Management Program Basis Document - External Surfaces Monitoring of Mechanical Components, Section 3.2, Procedural Controls, states that the program is governed by procedure ADM-17.33, License Renewal Systems/ Programs Monitoring.

Section 7.0, Summary of Implementing Documents, of the program basis document identifies the procedures that implement the External Surfaces Monitoring of Mechanical Components (External Surfaces) AMP and includes an extensive list of changes for ADM-17.33 that correspond to the program enhancements for the External Surfaces AMP listed in the SLRA.

The staff notes that in the program basis document, the last action listed in the Section 7.0 table for ADM-17.33 is Revise walkdown inspection forms to identify new requirements and components to be inspected. The staff notes that Attachments 1 through 21 of ADM-17.33 define the specific walkdown scope of the programs comprehensive condition monitoring and that the license renewal walkdowns shall be performed in accordance with these Attachments 1 through 21.

Issue Except for the last action in the Section 7.0 table noted above, all of the other actions describing changes to ADM-17.33 have corresponding enhancements discussed in the SLRA Section B.2.3.23, External Surfaces Monitoring of Mechanical Components, with corresponding commitments in SLRA Table 19-3, Item No. 26, commitments a) through o). The staff notes that in the current version of ADM-17.33, Attachments 1 through 21 do not include all the components that were designated as being included in the External Surfaces AMP.

It is not clear to the staff why the action to revise the walkdown inspections forms found in Attachments 1 through 21 in ADM-17.33, as described in the program basis document, does not have a corresponding enhancement and commitment.

Request Provide a basis to clarify the apparent lack of an enhancement and commitment discussed above, or alternatively revise the SLRA to include an enhancement in B.2.3.23 and a commitment in Table 19-3, Item 26 to include revising the walkdown inspection forms in ADM-17.33 to identify new requirements and components to be inspected.

RAI 4.7.1-1 Regulatory Basis Pursuant to 10 CFR 54.21(c), the SLRA shall include an evaluation of time-limited-aging analyses (TLAAs). The applicant shall demonstrate that (i) the analyses remain valid for the

[subsequent] period of extended operation; (ii) the analyses have been projected to the end of the [subsequent] period of extended operation; or (iii) the effects of aging on the intended function(s) will be adequately managed for the [subsequent] period of extended operation.

Background

SLRA Section 4.7.1 Leak-Before-Break of Reactor Coolant System Piping, identifies Alloy 600/82/182 welds are susceptible to primary water stress corrosion cracking (PWSCC) and have been conservatively evaluated to consider the effects of PWSCC. Section 3.6.3 of NUREG-0800 states that PWSCC is considered an active degradation mechanism in Alloy 600/82/182 materials in PWRs and needs to be addressed.

Issue It is not clear that the applicants evaluation is consistent with the corresponding SLRA section 4.7.1 and Section 3.6.3 of NUREG-0800.

Request

• Please provide additional information to specifically describe what conservative evaluations were made to the Alloy 600/82/182 welds that are present at the PSL Unit 1 and 2 reactor coolant pump (RCP) suction and discharge nozzle that determined PWSCC is not a concern. Additionally, please identify how the applicant is demonstrating that PWSCC is not a potential source of pipe rupture as described in Standard Review Plan (SRP 3.6.3), Revision 1.

• Please provide additional information if PSL is considering an overlay of Alloy 690/52/152 to minimize the susceptibility to PWSCC based on the evaluations made to the Alloy 600/82/182 welds. If PSL is not considering an Alloy 690/52/152 overlay, please provide additional information to identify how the applicant is planning to monitor these welds for potential leakage from cracks or flaws.

Please revise the TLAA to include the requested information provided above.