ML22013A303

Trp 143.2 St Lucie SLRA - Breakout Questions Non-Class 1 Fatigue

ML22013A303
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: ML22013A303 (2)

Text

Page 1 of 2 Plant Name SLRA: Breakout Questions SLRA Section 4.3.2, Metal Fatigue of Non-Class 1 Components TRP: 143.2 Note: Breakout Questions are provided to the applicant and will be incorporated into the publicly-available audit report.

Technical Reviewer Seung Min 11/29/2021 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 Number SLRA Section SLRA Page Background / Issue (As applicable/needed)

Discussion Question / Request Outcome of Discussion 1

4.3.2 (Table 4.3.2-2) 4.3-18 SLRA Table 4.3.3-2 indicates that the reactor coolant sampling line is subject to approximately 29200 cycles for 80 years of operation. Therefore, the relevant stress range reduction factor for the sampling lines is 0.7, which allows thermal cycles up to 45,000.

However, the SLRA does not clearly discuss how the stress analysis for sampling lines with the stress reduction factor (0.7) meets a relevant acceptance criterion.

1. Clarify whether the thermal expansion stress (SE) of the sampling lines meets the acceptance criterion (i.e., the stress does not exceed the allowable stress range (SA), as modified by applying the stress reduction for the piping). As part of the clarification, provide the SE and SA values.

Page 2 of 2 Question Number SLRA Section SLRA Page Background / Issue (As applicable/needed)

Discussion Question / Request Outcome of Discussion 2

4.3.2 4.3-16 SLRA Section 4.3.2 indicates that the non-Class 1 mechanical systems or portions of systems with operating temperatures above 220 °F are conservatively evaluated for metal fatigue. This approach is based on the applicants determination that the non-Class 1 piping at an operating temperature below 220 °F is not susceptible to thermal fatigue.

The staff needs to clarify whether the approach for determining susceptibility to thermal fatigue for 80 years of operation is consistent with that used in the current licensing basis non-Class 1 fatigue analysis.

1. Clarify whether the approach for determining susceptibility to thermal fatigue for 80 years of operation is consistent with that used in the current licensing basis non-Class 1 fatigue analysis. If not, explain why a different approach is used.