ML24348A072
| ML24348A072 | |
| Person / Time | |
|---|---|
| Site: | 05200050 |
| Issue date: | 12/13/2024 |
| From: | NuScale |
| To: | Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML24348A006 | List:
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| References | |
| LO-176318 | |
| Download: ML24348A072 (1) | |
Text
Response to NuScale Topical Report Audit Question Question Number: A-NonLOCA.LTR-54 Receipt Date: 06/24/2024 Question:
Please make available for audit the sensitivity studies performed for Main Steam Isolation Valve(s) Closure event. TR Section 72.8 states: "Sensitivity studies are performed as needed to identify the limiting response(s) for the acceptance criteria parameter(s) challenged by the event (i.e., system pressures for overheating events, MCHFR for overcooling events).
Consequently,sensitivity studies are performed to identify cases with the highest pressure responses for this overheating event."
Response
The quoted discussion from Section 7.2.8 of TR-0516-49416-P, Revision 4, Non-Loss-of-Coolant Accident Analysis Methodology, provides the methodology for the analysis. The methodology identifies that sensitivity studies are performed as needed. The focus of this overheating event is on system pressure response.
The application of this methodology for the US460 Standard Design Approval Application (SDAA) is documented in the Final Safety Analysis Report (FSAR). The event corresponding to Section 7.2.8 of TR-0516-49416-P is identified in FSAR Section 15.2.4. The analysis supporting FSAR Section 15.2.4 is documented in EC-117482, Revision 0, NPM-20 Main Steam Isolation Valve Closure Transient Analysis. EC-117482 was previously provided in the electronic reading room (eRR) for FSAR Chapter 15 for audit. Section 3.3.4 of EC-117482 identifies the sensitivity studies performed and considers parameters consistently with those identified in Table 7-40 of TR-0516-49416-P as being varied. The sensitivity results are summarized in Tables 5-1 and 5-2. The limiting peak system pressures of the cases in EC-117482 are reported in FSAR Table 15.2-12.
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In summary, the sensitivity studies described by Section 7.2.8 of TR-0516-49416-P have been previously made available for audit as part of the implementation of the methodology.
No changes to the SDAA are necessary.
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