ML24215A136
| ML24215A136 | |
| Person / Time | |
|---|---|
| Site: | 05200050 |
| Issue date: | 08/02/2024 |
| From: | NuScale |
| To: | Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML24215A000 | List:
|
| References | |
| LO-169995 | |
| Download: ML24215A136 (1) | |
Text
{{#Wiki_filter:Response to NuScale Technical Report Audit Question Question Number: A-5.PTLR-17 Receipt Date: 10/20/2023 Question: NuScale provided EC-107452 R1 in response to audit Questions A-5.PTLR-2, 3, 4, and 5. Based on the information provided in EC-107452 R1: Page 114: Equation 3 Please confirm the correctness of Equation 3-13 and subsequent equations that derive from it. Please confirm which equation was used to calculate the allowable pressure P. The staff notes that (Kim) (Mm
- Ri / t).
A follow-up question was issued on December 5, 2023:
The staff could not validate the derivation in the response. Follow-up question received on January 19, 2024:
See response above for PTLR-14. Staff recommends deleting the addition in the text before equation 3-13.
Equations 3-14, 3-15, and 3-16 in the SDAA should be corrected such that KIm is replaced by (KIm)p=1psi
Response
Original Response: Equation 3-13 of EC-107452, Revision 2, and the equations subsequently derived are correct for determining the allowable pressure for the four defined transients. Equation 3-2 and Equation 3-5 of EC-107452 calculate the maximum stress intensity factor (KIm), where the NuScale Nonproprietary NuScale Nonproprietary
pressure of the three-dimensional model is 1 psig. The generalized form of Equation 3-2 and Equation 3-5 is shown below for clarification. (KIm/p) = (Mm
- Ri / t) Where p = 1 psig Revision 2 of EC-107452 is in the electronic reading room in response to audit question A-5.PTLR-18.
Response to NRC Follow-up Question received on December 4, 2023: The attached markup to TR-130877-P shows the updated derivation in Equation 3-13, as noted in the revised response to A-5.PTLR-14. Response to NRC Follow-up Question received on January 19, 2024: The text prior to equation 3-13 in TR-130877-P, Pressure and Temperature Limits Methodology, has been removed. As stated in the revised response to audit question A-5.PTLR-14, equations 3-13 through 3-16 in TR-130877-P, Pressure and Temperature Limits Methodology, have been revised to replace Klm/1 psi with (Klm/p)p = 1 psi. Markups of the affected changes, as described in the response, are provided below: NuScale Nonproprietary NuScale Nonproprietary
Pressure and Temperature Limits Methodology TR-130877-NP Draft Revision 1 © Copyright 2024 by NuScale Power, LLC 27 Audit Question A-5.PTLR-14, Audit Question A-5.PTLR-17 The allowable pressure associated with a specified temperature along a P-T limits curve is: Eq. 3-13 The appropriate and values used for various conditions are:
For preservice hydrostatic tests, a steady-state condition ( ) is applied, and the required structural factor Audit Question A-5.PTLR-14, Audit Question A-5.PTLR-17 Eq. 3-14 Performance of the allowable pressure calculation occurs for the crack with highest that bounds other cracks. The basis for the preservice limiting pressure is NUREG-0800, Section 5.3.2 (Reference 6.1.4). For the heat up and cooldown transients, the thermal SIF calculation occurs at selected time points, and the required structural factor Audit Question A-5.PTLR-14, Audit Question A-5.PTLR-17 Eq. 3-15 For ISLH, the SIF from heat up and cooldown transients conservatively apply to the most limiting crack, and the required structural factor Audit Question A-5.PTLR-14, Audit Question A-5.PTLR-17 Eq. 3-16 3.3.4.6 10 CFR 50, Appendix G, Pressure and Temperature Limits Appendix G of Reference 6.1.3 requires that the P-T limits are at least as conservative as limits obtained by following the Appendix G of Reference 6.1.5, methods presented in Section 3.3.4.5. Additionally, Table 1 of Appendix G of Reference 6.1.3 requires further limitations (Table 3-3). P KIC KIT ( )t SF Mm Ri
KIC KIT SF KIm p
( )p 1 = psi
= = KIT SF KIT 0 = SF 1 = P KICt Mm Ri
KIC KIm p
( )p 1 = psi = = Mm KIT SF 2 = P KIC KIT ( )t 2Mm Ri
KIC KIT 2 KIm p
( )p 1 = psi = = KIT SF 1.5 = P KIC KIT ( )t 1.5Mm Ri
KIC KIT 1.5 KIm p
( )p 1 = psi = =}}