L-2022-165, Subsequent License Renewal Application - Aging Management Request for Additional Information (RAI) 4.3.1-1a(second Round) - Class 1 Fatigue Response

Subsequent License Renewal Application - Aging Management Request for Additional Information (RAI) 4.3.1-1a(second Round) - Class 1 Fatigue Response

ML22299A037
Person / Time
Site:	Saint Lucie
Issue date:	10/26/2022
From:	Maher W Florida Power & Light Co
To:	Office of Nuclear Reactor Regulation, Document Control Desk
References
L-2022-165
Download: ML22299A037 (1)

Text

October 26, 2022 L-2022-165 10 CFR 54.17 U.S. Nuclear Regulatory Commission Attn: Document Control Desk 11545 Rockville Pike One White Flint North Rockville, MD 20852-2746 St. Lucie Nuclear Plant Units 1 and 2 Dockets 50-335 and 50-389 Renewed Facility Operating Licenses DPR-67 and NPF-16 SUBSEQUENT LICENSE RENEWAL APPLICATION - AGING MANAGEMENT REQUEST FOR ADDITIONAL INFORMATION (RAI) 4.3.1-1a SECOND ROUND) - CLASS 1 FATIGUE RESPONSE

References:

1. FPL Letter L-2021-192 dated October 12, 2021 - Subsequent License Renewal Application -

Revision 1 (ADAMS Accession No. ML21285A107) 2. FPL Letter L-2022-043 dated April 7, 2022 - Subsequent License Renewal Application Revision 1 - Supplement 1 (ADAMS Accession No. ML22097A202) 3. FPL Letter L-2022-044 dated April 13, 2022 - Subsequent License Renewal Application Revision 1 - Supplement 2 (ADAMS Accession No. ML22103A014) 4. FPL Letter L-2022-071 dated May 19, 2022 - Subsequent License Renewal Application Revision 1 - Supplement 3 (ADAMS Accession No. ML22139A083) 5. NRC Email and Attachment dated May 12, 2022, St. Lucie SLRA - Request for Additional Information Set #1 (FINAL) (ADAMS Accession Nos. ML22133A002, ML22133A003) 6. NRC Email and Attachment dated May 26, 2022, St. Lucie SLRA RCI Set 1 Final (ADAMS Accession Nos. ML22147A086, ML22147A087) 7. FPL Letter L-2022-075 dated June 13, 2022 - Subsequent License Renewal Application -

Aging Management Requests for Additional Information (RAI) Set 1A Response and Request for Confirmation of Information (RCI) Set 1 Response (ADAMS Accession No. ML22164A802) 8. FPL Letter L-2022-081 dated June 30, 2022 - Subsequent License Renewal Application -

Aging Management Requests for Additional Information (RAI) Set 1B Response (ADAMS Accession No. ML22181A147) 9. FPL Letter L-2022-154 dated September 22, 2022 - Subsequent License Renewal Application Revision 1 - Supplement 4 (ADAMS Accession No. ML22265A134) 10.NRC Email and Attachment dated September 26, 2022, St. Lucie SLRA - Request for Additional Information (Second Round #2 - Class ) (ADAMS Accession Nos.

ML22270A148, ML22270A149)

Florida Power & Light Company





15430 Endeavor Drive, Jupiter, FL 33478

St. Lucie Nuclear Plant Units 1 and 2 Dockets 50-335 and 50-389 L-2022-165 l Page 2 of 2 Florida Power & Light Company (FPL), owner and licensee for St. Lucie Nuclear Plant (PSL) Units 1 and 2, has submitted a revised and supplemented subsequent license renewal application (SLRA) for the Facility Operating Licenses for PSL Units 1 and 2 (References 1-4). Based on the NRCs review of the SLRA, the NRC issued its Set 1 RAIs and RCI to FPL (References 5 and 6).

References 7 and 8 provided responses to the RAIs and RCI with additional clarifying information provided in Reference 9. Upon review of these responses, the NRC requested additional information regarding the response to RAI 4.3.1-1a in Reference 10. The attachment to this letter provides the requested additional information in response to RAI 4.3.1-1a.

The attachment includes associated revisions to the SLRA (Enclosure 3 Attachment 1 of Reference 1, as supplemented by References 2 - 4) denoted by strikethrough (deletion) and/or bold red underline (insertion) text. Previous SLRA revisions are denoted by bold black text. SLRA table revisions are included as excerpts from each affected table.

Should you have any questions regarding this submittal, please contact me at (561) 304-6256 or William.Maher@fpl.com.

I declare under penalty of perjury that the foregoing is true and correct.

Executed on the 26TH day of October 2022.

Sincerely, William Digitally signed by William Maher DN: cn=William Maher, o=Nuclear, ou=Nuclear Licensing Projects, Maher email=william.maher@fpl.com, c=US Date: 2022.10.26 09:19:50 -04'00' William D. Maher Licensing Director - Nuclear Licensing Projects Florida Power & Light Company

Attachment:

PSL Response to NRC RAI No. 4.3.1-1a Cc: Regional Administrator, USNRC, Region II Senior Resident Inspector, USNRC, St. Lucie Plant Chief, USNRC, Division of New and Renewed Licenses Senior Project Manager, USNRC, Division of New and Renewed Licenses Chief, Bureau of Radiation Control, Florida Department of Health

St. Lucie Units 1 and 2 Dockets 50-335 and 50-389 PSL Response to NRC RAI No. 4.3.1-1a L-2022-165 Attachment 1 Page 1 of 8 Metal Fatigue of Class 1 Components RAI 4.3.1-1a 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:

In the June 30, 2022, response to RAI 4.3.1-1, the applicant explained that cycle counting is not performed on the following design transients of St. Lucie Unit 1: (1) low volume control and makeup; (2) cold feed following hot standby; (3) actuation of main or auxiliary spray; (4) low pressure safety injection, 40ºF water into 300ºF cold leg; (5) opening of safety injection return line valves; and (6) loss of feedwater flow (ADAMS Accession No. ML22181A147).

The applicant explained that cycle counting is not performed on these transients based on (1) the component CUF (cumulative usage factor) value associated with the transients is not greater than 0.1 or (2) if the CUF of an associated component is greater than 0.1, the contribution of each transient to the CUF is not greater than 0.1.

Issue:

The applicants response to RAI 4.3.1-1 does not clearly address how the applicant considered the combined effects of these transients on CUF in the determination of cycle counting exclusion. Multiple uncounted transients could cause combined contributions to the overall CUF of a component so that the fatigue monitoring may be ineffective.

In relation to this concern, the staff noted that the following reference describes the applicants CUF evaluation for the Class 1 components and reactor coolant system piping of St. Lucie Unit 1 (

Reference:

PSL-1FSC-01-005, Revision 1, Screening of ASME Class 1 Components for License Renewal TLAA Thermal Fatigue). The reference addresses the CUF contributions of limiting transients for each component, where a limiting transient is a transient contributing to the CUF of a component more than 0.1 and is also called a fatigue-sensitive transient.

The reference also indicates that the overall CUF contribution of non-limiting transients is in the range from 0.21 to 0.78 for the following Unit 1 components: (1) steam generator primary head at divider seat bar; (2) pressurizer bottom head support skirt; (3) surge line resistance temperature detector (RDT) nozzle; and (4) surge line sample nozzle. The staff is seeking clarification whether the non-limiting transients for these components include multiple uncounted transients.

St. Lucie Units 1 and 2 Dockets 50-335 and 50-389 PSL Response to NRC RAI No. 4.3.1-1a L-2022-165 Attachment 1 Page 2 of 8 Request:

Clarify whether two or more uncounted transients are included in the non-limiting transients for the following Unit 1 components: (1) steam generator primary head at divider seat bar; (2) pressurizer bottom head support skirt; (3) surge line RTD nozzle; and (4) surge line sample nozzle. If so, discuss why cycle counting is not needed for the transients even though multiple uncounted transients could cause combined contributions to the overall CUF of a component so that the fatigue monitoring may be ineffective.

PSL Response:

The response below provides clarification whether two or more uncounted transients are included in the non-limiting transients for the four PSL-1 RCS Class 1 component locations identified in the NRC request.

(1) Steam generator primary head at divider seat bar The supporting references in Reference 1 identify the following transients considered in the fatigue analysis for the steam generator primary head at divider seat bar.

Acceptable Transient Transient Disposition Disposition not Counted in Committed to for not Transients Evaluated to Count per SLRA Table Count per Counting for Fatigue Attachments 1 4.3.1-1 of Attachment 4 Provided and 3 of Reference 2 of Reference 3 Below Reference 3 Warmup* / Cooldown Y Plant Loading / Unloading Y 10% Step Load Increase /

Y Decrease Cold Feedwater Following Y

Hot Standby Normal Plant Variations Y Primary Coolant Pump Y

Start / Stop Reactor Trip** Y Loss of Primary Flow** Y Loss of Load** Y Operating Basis Y

Earthquake Primary Leak Test Y Secondary Leak Test Y

• Warmup = Heatup

• • These transients are combined as a lumped transient

St. Lucie Units 1 and 2 Dockets 50-335 and 50-389 PSL Response to NRC RAI No. 4.3.1-1a L-2022-165 Attachment 1 Page 3 of 8 The total CUF at this component location is 0.957, of which 0.746 is due to Heatup /

Cooldown (0.606) and Warmup / Cooldown Lumped (Reactor Trip + Loss of Flow + Loss of Load = 0.14). A cumulative fatigue usage of 0.211, therefore, is associated with the remaining transients, which are discussed as follows:

Committed to count in SPEO x Plant Loading / Unloading (Note that very few plant loading and unloading transients have occurred to date at PSL-1 and PSL-2 as both units have historically been operated as base-loaded units. Since there is large margin between the actual transient counts to date and the design limit of 15,000 cycles, the plant loading and unloading transients are currently not counted during the 60-year PEO. However, this transient will be counted in the 80-year SPEO, as explained in Attachment 4 of Reference 3) x 10% Step Load Increase / Decrease (counted in the SPEO, per Attachment 4 of Reference 3) x Primary Leak Test (counted in the SPEO, per Table 4.3.1-1 of Reference 2) x Secondary Leak Test (counted in the SPEO, per Table 4.3.1-1 of Reference 2)

Acceptable disposition for not counting already established x Normal Plant Variations (acceptable not to count, per Attachment 1 of Reference 3) x Primary Coolant Pump Start / Stop (acceptable not to count, per Attachment 1 of Reference 3) x Operating Basis Earthquake (acceptable not to count, per Attachment 3 of Reference 3)

As discussed in the response to Attachment 1 of Reference 3, there are 1,000,000 Normal Plant Variations cycles, which is considered an infinite number. The Normal Plant Variations transient is considered in fatigue analyses to account for minor changes in pressure and temperature that by themselves do not contribute to fatigue usage. This transient provides conservatism in the calculated design CUF value.

As discussed in Section 4.7.4 of the SLRA (Reference 2), not more than 2,000 Reactor Coolant Pump Start / Stop cycles are conservatively projected through the SPEO based on 500 Heatup and Cooldown cycles. This provides a margin of at least 50% to the 4,000 cycles used in the design fatigue analysis. Since this transient does not contribute more than 0.1 to the CUF, the contribution would be not more than 0.05.

As also discussed in the responses presented in Attachments 1 and 3 of Reference 3, cycle monitoring is not required for the Operating Basis Earthquake due to the large projected cycle margin.

The only remaining transient to discuss is the Cold Feedwater Following Hot Standby transient. The margin between the projected 80-year transient cycles and design cycles for the counted transients in SLRA Table 4.3.1-1 (Reference 2) is 60% or greater. It is therefore reasonable to conclude that the number of Cold Feedwater Following Hot Standby

St. Lucie Units 1 and 2 Dockets 50-335 and 50-389 PSL Response to NRC RAI No. 4.3.1-1a L-2022-165 Attachment 1 Page 4 of 8 transient cycles in 80 years of operation will also be significantly less than the large number (15,000) of cycles used in the design analysis. As with the Reactor Coolant Pump Start /

Stop cycles, if a conservative margin of 50% is applied, this transient would contribute 0.05 to the CUF.

In summary, there are a total of four uncounted transients: Normal Plant Variations, Primary Coolant Pump Start / Stop, Operating Basis Earthquake and Cold Feedwater Following Hot Standby. The total contribution to the CUF from these uncounted transients is expected to be not more than 0.1 due to the significant margin between 80-year projections and cycles assumed in design fatigue calculations. This is consistent with the value of 0.1 used as a cutoff for any single fatigue-sensitive transient in SIR-01-102 (Reference 4) and confirms that the methodology utilized to determine which design transients require counting by the PSL Fatigue Monitoring AMP is acceptable and provides reasonable assurance that the effects of aging will be managed such that the intended function(s) of components within the scope of SLR will be maintained during the SPEO.

The above discussion justifying why cycle counting is not needed for any transients included in the non-limiting transients for the steam generator primary head at divider seat bar alleviates the concern that multiple uncounted transients could cause combined contributions to the overall CUF of the steam generator primary head at divider seat bar such that fatigue monitoring may be ineffective.

(2) Pressurizer bottom head support skirt The Reference 1 calculation provides the license renewal CUF evaluation for the original PSL-1 pressurizer component locations. The pressurizer bottom head support skirt component location is included in that CUF evaluation. However, as discussed in Section 4.3.1 of the PSL SLRA (Reference 2), the original PSL-1 pressurizer, including the bottom head support skirt, was replaced in 2005. Therefore, the CUF evaluation for the original pressurizer component locations in Reference 1 are no longer applicable and have been superseded by the fatigue analysis performed by Framatome for the replacement pressurizer.

To address this RAI, the CUF evaluation of the corresponding PSL-1 replacement pressurizer component location, which is referred to as the pressurizer head skirt connection, is provided in this response. The Framatome fatigue analysis for the replacement pressurizer head skirt connection limiting component location calculated an overall CUF value greater than 0.1. Since this overall CUF value exceeds the license renewal CUF screening criteria of 0.1, additional review is required to identify those transients that need to be counted by the PSL Fatigue Monitoring AMP. This review concludes that there are only two transients, plant heatup and plant cooldown, that provide a CUF contribution of greater than 0.1 to the overall CUF value. Therefore, these two transients require counting by the PSL Fatigue Monitoring AMP. The other transients included in the fatigue analysis for this limiting component location provide a total less than the license renewal CUF screening criteria of 0.1.

St. Lucie Units 1 and 2 Dockets 50-335 and 50-389 PSL Response to NRC RAI No. 4.3.1-1a L-2022-165 Attachment 1 Page 5 of 8 For completeness, the table below identifies all the transients included in the fatigue analysis for replacement pressurizer head skirt limiting component location:

Transient Transient Counted Committed to Transients Evaluated in Table 4.3.1-1 of Count per for Fatigue Reference 2 Attachment 4 of Reference 3 Heatup / Cooldown Y Plant Loading / Unloading Y Reactor Trip Y Leak Test Y The table above demonstrates that all transients included in the PSL-1 replacement pressurizer head skirt fatigue analysis will be counted by the PSL Fatigue Monitoring AMP during the SPEO, regardless of the magnitude of their CUF contributions. In addition, this review of the PSL-1 replacement pressurizer head skirt fatigue analysis confirms that there are no multiple uncounted transients that could cause combined contributions to the overall CUF of a component such that fatigue monitoring might be ineffective.

(3) Surge line RTD nozzle The Reference 1 supporting reference identifies both stratified and non-stratified transients evaluated for fatigue of the surge line RTD nozzle. Stratified transients consist of a defined set of transients that occur during Heatup and Cooldown at various differential temperatures between the pressurizer and hot leg, which are accounted for in counting the Heatup /

Cooldown transients and the Hot Standby 90°F transient, which is covered by the Cooldown transient per Table 2-1 of Reference 4.

The list of non-stratified transients is as follows:

Acceptable Transient Transient Disposition Disposition not Counted in Committed to for not Transients Evaluated to Count per SLRA Table Count per Counting for Fatigue Attachments 1 4.3.1-1 of Attachment 4 Provided and 3 of Reference 2 of Reference 3 Below Reference 3 Heatup / Cooldown Y Plant Loading / Unloading Y 10% Step Load Increase /

Y Decrease Reactor Trip Y Leak Test at Heatup /

Y Cooldown Normal Plant Variations Y Loss of Flow (Load) Y

St. Lucie Units 1 and 2 Dockets 50-335 and 50-389 PSL Response to NRC RAI No. 4.3.1-1a L-2022-165 Attachment 1 Page 6 of 8 Acceptable Transient Transient Disposition Disposition not Counted in Committed to for not Transients Evaluated to Count per SLRA Table Count per Counting for Fatigue Attachments 1 4.3.1-1 of Attachment 4 Provided and 3 of Reference 2 of Reference 3 Below Reference 3 Loss of Secondary Y

Pressure No Load

• Y Seismic (Operating Basis Y

Earthquake)

Although listed here as a transient, this is not a design transient and represents a static, zero load stress state (zero pressure and ambient conditions).

There are two uncounted transients: Normal Plant Variations and Operating Basis Earthquake. The No Load transient is not a loading condition; rather it is a static stress state used in fatigue analyses to account for transient cycles not otherwise paired in the fatigue table and provide conservatism in the calculated CUF value.

There are 1,000,000 Normal Plant Variations cycles, which is considered an infinite number.

The Normal Plant Variations transient is considered in fatigue analyses to account for minor changes in pressure and temperature that by themselves do not contribute to fatigue usage.

This transient provides conservatism in the calculated design CUF value.

The total CUF contribution (of the uncounted transients) is 0.027, which is below the value of 0.1 used as a cutoff for any single fatigue-sensitive transient in SIR-01-102 (Reference 4).

This confirms that the methodology utilized to determine which design transients require counting by the PSL Fatigue Monitoring AMP is acceptable and provides reasonable assurance that the effects of aging will be managed such that the intended function(s) of components within the scope of SLR will be maintained during the SPEO.

The above discussion justifying why cycle counting is not needed for any transients included in the non-limiting transients for the surge line RTD nozzle alleviates the concern that multiple uncounted transients could cause combined contributions to the overall CUF of the surge line RTD nozzle such that fatigue monitoring may be ineffective.

(4) Surge line sample nozzle The Reference 1 supporting reference identifies both stratified and non-stratified transients evaluated for fatigue of the surge line sample nozzle. Stratified transients consist of a defined set of transients that occur during Heatup and Cooldown at various differential temperatures between the pressurizer and hot leg, which are accounted for in counting the Heatup / Cooldown transients and the Hot Standby 90°F transient, which is covered by the Cooldown transient per Table 2-1 of Reference 4.

The list of non-stratified transients is as follows:

St. Lucie Units 1 and 2 Dockets 50-335 and 50-389 PSL Response to NRC RAI No. 4.3.1-1a L-2022-165 Attachment 1 Page 7 of 8 Acceptable Transient Transient Disposition Disposition not Counted in Committed to for not Transients Evaluated to Count per SLRA Table Count per Counting for Fatigue Attachments 1 4.3.1-1 of Attachment 4 Provided and 3 of Reference 2 of Reference 3 Below Reference 3 Heatup / Cooldown Y Plant Loading / Unloading Y 10% Step Load Increase /

Y Decrease Reactor Trip Y Leak Test at Heatup /

Y Cooldown Normal Plant Variations Y Loss of Flow (Load) Y Loss of Secondary Y

Pressure No Load

• Y Seismic (Operating Basis Y

Earthquake)

Although listed here as a transient, this is not a design transient and represents a static, zero load stress state (zero pressure and ambient conditions).

There are two uncounted transients: Normal Plant Variations and Operating Basis Earthquake. The No Load transient is not a loading condition; rather it is a static stress state used in fatigue analyses to account for transient cycles not otherwise paired in the fatigue table and provide conservatism in the calculated CUF value.

There are 1,000,000 Normal Plant Variations cycles, which is considered an infinite number.

The Normal Plant Variations transient is considered in fatigue analyses to account for minor changes in pressure and temperature that by themselves do not contribute to fatigue usage.

This transient provides conservatism in the calculated design CUF value.

The total CUF contribution (of the uncounted transients) is 0.098, which is below the value of 0.1 used as a cutoff for any single fatigue-sensitive transient in SIR-01-102 (Reference 4) and confirms that the methodology utilized to determine which design transients require counting by the PSL Fatigue Monitoring AMP is acceptable and provides reasonable assurance that the effects of aging will be managed such that the intended function(s) of components within the scope of SLR will be maintained during the SPEO.

The above discussion justifying why cycle counting is not needed for any transients included in the non-limiting transients for the surge line sample nozzle alleviates the concern that multiple uncounted transients could cause combined contributions to the overall CUF of the surge line sample nozzle such that the fatigue monitoring may be ineffective.

St. Lucie Units 1 and 2 Dockets 50-335 and 50-389 PSL Response to NRC RAI No. 4.3.1-1a L-2022-165 Attachment 1 Page 8 of 8

==

Conclusion:==

The evaluations above confirm that the methodology utilized to determine which design transients require counting by the PSL Unit 1 and 2 Fatigue Monitoring AMP is acceptable and provides reasonable assurance that the effects of aging will be managed such that the intended function(s) of components within the scope of SLR will be maintained during the SPEO.

References:

1. FPL Calculation No. PSL-1FSC-01-005, Revision 1, Screening of ASME Class 1 Components for License Renewal TLAA Thermal Fatigue, dated September 19, 2001

2. FPL Letter L-2021-192 dated October 12, 2021, Subsequent License Renewal Application - Revision 1 (ADAMS Accession No. ML21285A107)

3. FPL Letter L-2022-081 dated June 30, 2022, Subsequent License Renewal Application -

Aging Management Requests for Additional Information (RAI) Set 1B Response (ADAMS Accession No. ML22181A147)

4. Structural Integrity Associates Report No. SIR-01-102, Revision 3, Thermal Cycle Evaluation for St. Lucie Units 1 and 2, dated November 7, 2014 Associated SLRA Revisions:

None.

Associated

Enclosures:

None.