ML22024A046

Breakout Questions - Trp 143.2 - Non-Class 1 Fatigue Analyses

ML22024A046
Person / Time
Site:	Oconee
Issue date:	01/19/2022
From:	Angela Wu NRC/NRR/DNRL/NLRP
To:
Wu A, 301-415-2995
Shared Package
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References
Download: ML22024A046 (2)

Text

Oconee SLRA: Breakout Questions SLRA Section 4.3.3, Non-Class 1 Piping Fatigue Analyses TRP: 143.2 Question SLRA SLRA Background / Issue Discussion Question / Request Number Section Page (As applicable/needed) 1 4.3.3 4-66 SLRA Section 4.3.3 addresses the fatigue 1. Describe how the applicant (Table TLAA for the Non-Class 1 piping systems. determined the cycle 4.3.3-2) Specifically, SLRA Table 4.3.3-2 provides projection basis for the non-80-year thermal cycle projections for the Class 1 piping systems. As piping systems and conservative cycles part of the response, used in the cycle projections. discuss relevant references that were used to determine The applicant also provided the specific the conservative projection cycle numbers associated heatup, basis (e.g., by using the cooldown or other relevant cycles, or operating procedures, cycle number per a specific time period manuals or test (e.g., monthly cycles). However, the requirements for the piping applicant did not describe how the systems).

conservative basis of the cycle projections was determined. The staff needs additional information to clarify the 2. Provide the number of basis of the cycle projections. emergency feedwater actuation cycles per year, which is used in the cycle projections.

2 4.3.3 4-66 SLRA Section 4.3.3 indicates that none of 1. Clarify whether the thermal (Table non-class 1 piping lines in scope for SLR expansion stress (SE) of 4.3.3-2) exceed the allowable number of thermal the pressurizer sampling cycles specified in ANSI B31.1 Code and, piping meets the therefore, the stress range reduction acceptance criteria (i.e.,

factors applied to the piping systems the stress does not exceed remain valid in all locations. In the allowable stress range comparison, SLRA Table 4.3.3-2, Note 1 (SA), as modified by indicates that the pressurizer sampling applying the stress Page 1 of 2

Question SLRA SLRA Background / Issue Discussion Question / Request Number Section Page (As applicable/needed) piping stress range reduction factor has reduction factor of 0.7 for been reduced from 1.0 to 0.7 to allow a the piping). As part of the total of 45,000 cycles for the piping. clarification, provide the SE and SA values.

The staff finds a need to confirm that the updated stress reduction factor for the pressurizer sampling system (from 1.0 to 0.7) is adequately used in the stress analysis for the piping system and the related stress analysis is acceptable.

3 4.3.3 4-66 The following reference indicates that the Discuss (1) whether the use of (Table applicant used a threshold temperature of the threshold temperature (220 4.3.3-2) 220 °F to identify and screen out non- °F) is consistent with the class 1 piping systems, for which the Oconee CLB analysis for non-effect of thermal fatigue is insignificant Class 1 metal fatigue and (2)

(

Reference:

SLR-ONS-TLAA-0304, Non- the basis of the threshold Class 1 Mechanical Metal Fatigue, temperature used to determine Revision 1, Seciton 3.0). the insignificant effect of The staff needs to clarify (1) whether the thermal fatigue.

use of the threshold temperature (220 °F) is consistent with the Oconee current In addition, identify the most licensing basis (CLB) analysis for non- limiting (most frequently Class 1 metal fatigue and (2) the basis of cycled) non-Class 1 piping the threshold temperature used to system except the pressurizer determine the insignificant effect of sampling piping.

thermal fatigue.

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