ML22013A301

TRP60 St. Lucie SLRA - Breakout Questions Fatigue Monitoring

ML22013A301
Person / Time
Site:	Saint Lucie
Issue date:	12/21/2021
From:	Office of Nuclear Reactor Regulation
To:
Rodriguez-Luccioni H
References
EPID L-2021-SLR-0002, L-2021-SLR-0002
Download: ML22013A301 (5)

Text

St. Lucie SLRA: Breakout Questions SLRA Section B.2.2.1, Fatigue Monitoring TRP: 60 Note: Breakout Questions are provided to the applicant and will be incorporated into the publicly-available audit report.

Technical Reviewer Seung Min 12/9/2021 Technical Branch Chief Matt Mitchell 12/21/2021 Breakout Session Date/Time To be filled in by PM Applicant Staff NRC staff To be filled out by PM during breakout Question SLRA SLRA Background / Issue Discussion Question / Request Outcome of Discussion Number Section Page (As applicable/needed) 1 B.2.2.1 B-24 SLRA Section B.2.2.1 indicates that a 1. Explain the acceptability of new limit of 500 cycles will be specified increasing the cycle limit for for the loss of letdown flow transient for the loss of letdown flow 80 years of operation, as listed in SLRA transient from 50 to 500.

Tables 4.3.1-5 and 4.3.1-6. This new As part of the discussion, cycle limit is significantly greater than the clarify whether the increase existing cycle limit of 50 that is listed in in the cycle limit can cause SLRA Table 4.3.1-1. In relation to this the projected 80-year discussion, Enhancement 3 of the environmental cumulative Fatigue Monitoring program addresses usage factors to exceed the the update to the plant procedure to design limit of 1.0. If so, monitor and track the loss of letdown describe how the aging flow transient for the subsequent period effect of EAF will be of extended operation (SPEO). managed.

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Question SLRA SLRA Background / Issue Discussion Question / Request Outcome of Discussion Number Section Page (As applicable/needed)

However, the SLRA does not clearly explain the acceptability of increasing the cycle limit for the loss of letdown flow transient from 50 to 500 in terms of environmentally assisted fatigue (EAF) analysis.

2 B.2.2.1 B-25 Enhancement 1 of the Fatigue Monitoring 1. Clarify whether the sulfate program is to update the program concentration of reactor governing procedure in order to monitor coolant is used as an input the chemistry parameters that provide parameter for the inputs to environmental fatigue correction applicants calculations of factors (Fen) used in environmental Fen and CUFen values. If cumulative usage factor (CUFen) so, explain why the use of calculations. The applicant also explained the sulfate concentration is that the chemistry parameters include consistent with the dissolved oxygen and sulfate and are guidance in NUREG/CR-controlled and tracked in accordance with 6909, Revision 1.

the Water Chemistry program (SLRA Section B.2.3.2).

The staff noted that the applicant relies on the guidance in NUREG/CR-6909, Revision 1 for calculating Fen and CUFen values. However, the guidance does not identify sulfate concentration as an input parameter for Fen and CUFen calculations.

Therefore, the staff found a need to clarify whether the sulfate concentration of reactor coolant is used as an input parameter for the applicants calculations of Fen and CUFen values.

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Question SLRA SLRA Background / Issue Discussion Question / Request Outcome of Discussion Number Section Page (As applicable/needed) 3 B.2.2.1 B-25 Enhancement 2 of the Fatigue Monitoring 1. Clarify whether program is to update the program Enhancement 2 includes governing procedure in order to identify the monitoring of the and require monitoring of the 80-year transients associated with plant design cycles, or projected cycles the reduced cycles (i.e.,

that are utilized as inputs to CUFen plant loading, plant (environmental cumulative usage factor) unloading, purification calculations, as applicable. and boric acid dilution Tables 3-1 and 3-2 of Westinghouse LTR- transients) used in the EAF SDA-II-20-31-NP, Revision 2 provide the analysis. If not, provide leading environmentally-assisted fatigue the basis for excluding (EAF) locations for the equipment these transients from components and piping components, fatigue monitoring given respectively. Tables 3-1 and 3-2 indicate that the reduced cycles of that, for some equipment and piping these transients are used components, reduced cycles of designed in the EAF analysis.

transients are used for the EAF analysis, compared to the design transient cycles described in SLRA Section 4.3.1.

The staff noted that Enhancement 2 addresses the fatigue monitoring for the reduced cycles used in the EAF analysis.

However, some of the transients, which involve the reduced cycles in the EAF analysis, are not monitored in the Fatigue Monitoring program as discussed in SLRA Tables 4.3.1-1 and 4.3.1-2.

Specifically, the applicant proposed not to monitor the reduced cycles of the following transients used in the EAF analysis: (1) plant unloading transient (for Unit 1 control element driving mechanism motor housing, and Unit 1 and Page 3 of 5

Question SLRA SLRA Background / Issue Discussion Question / Request Outcome of Discussion Number Section Page (As applicable/needed) 2 charging system); (2) plant loading transient (for Unit 1 and 2 charging system); and (3) purification and boric acid dilution transients (for Unit 1 and 2 charging system).

The staff found a need to clarify whether Enhancement 2 includes the monitoring of these transients associated with the reduced cycles (i.e., plant loading, plant unloading, purification and boric acid dilution transients). If not, the staff needs to confirm the adequacy of the basis for excluding these transients from fatigue monitoring given that the reduced cycles of these transients are used in the EAF analysis.

4 B.2.2.1 B-25 Enhancement 5 of the Fatigue Monitoring 1. Clarify (1) what the program is to update the program additional acceptance governing procedure to add an additional criterion associated with acceptance criterion associated with high- HELB CUF criteria is and energy line break (HELB) CUF criteria. (2) why the criterion is This enhancement is applied only to St. needed (e.g., criterion is Lucie Unit 2 and is related to the HELB needed to determine HELB analyses addressed in SLRA Section locations).

4.3.4.

The staff noted that the enhancement 2. Describe any additional does not clearly define the additional corrective actions that may acceptance criterion associated with the need to be performed HELB CUF criteria. In addition, the beyond the actions enhancement does not clearly address specified in the corrective any additional corrective actions that may actions program element if Page 4 of 5

Question SLRA SLRA Background / Issue Discussion Question / Request Outcome of Discussion Number Section Page (As applicable/needed) need to be performed beyond the actions the additional criterion is specified in the corrective actions not met (e.g., additional program element if the additional criterion HELB analysis for newly associated with the HELB CUF criteria is identified break locations not met. and their effects).

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