ML24346A287
| ML24346A287 | |
| Person / Time | |
|---|---|
| Site: | 05200050 |
| Issue date: | 12/11/2024 |
| From: | NuScale |
| To: | Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML24346A130 | List:
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| References | |
| LO-175762 | |
| Download: ML24346A287 (1) | |
Text
Response to SDAA Audit Question Question Number: A-15.4.7-1 Receipt Date: 01/15/2024 Question:
Make available for audit the calculations supporting FSAR Section 15.4.7, Inadvertent Loading and Operation of a Fuel Assembly in an Improper Position.
Response
NuScale initially provided a response to this audit question on January 16, 2024. NRC staff feedback on this audit response was provided on January 31, 2024 and the feedback was subsequently discussed on a clarification call between NuScale and the NRC on February 1, 2024. As a follow-up action from the clarification call, NuScale has revised the response.
As described in Final Safety Analysis Report (FSAR) Section 15.4.7.3, there is no NPM thermal hydraulic transient analysis performed for the inadvertent loading and operation of a fuel assembly in an improper position (i.e., NRELAP5), but SIMULATE5 is used to determine the limiting undetectable fuel misload, and to provide peaking factors to the subchannel analysis.
The subchannel analysis, EC-115225, Rev. 2, Subchannel Analysis of Inadvertent Loading and Operation of a Fuel Assembly in an Improper Position, is provided in the electronic reading room (eRR).
((2(a),(c) NuScale Nonproprietary NuScale Nonproprietary NuScale Nonproprietary NuScale Nonproprietary
(( }}2(a),(c) NuScale Nonproprietary NuScale Nonproprietary
(( }}2(a),(c) An additional point raised in the clarification call is that there is the possibility that a misloaded configuration that goes undetected at beginning of cycle could be detected later as changes in power peaking, decrease in uranium enrichment, and gadolinium enrichment occur. Monitoring of the radial peaking in accordance with Technical Specification 3.2.1 could detect the misloaded configuration and would require a decrease in power until the issue is addressed. The analysis does not take credit for this possibility, rather it is assumed that the undetected cases at startup remain undetected throughout the cycle, with the subchannel calculation utilizing the bounding peaking increase. NuScale has reviewed FSAR Section 15.4.7 for the US460 Standard Design Approval Application (SDAA) and concludes the following:
The information is accurate.
The information is an adequate summary of the detailed discussion above.
The level of detail is consistent with the level of detail for the same FSAR section in the US600 Design Certification Application (DCA) previously approved by the NRC. No changes to the SDAA are necessary. NuScale Nonproprietary NuScale Nonproprietary}}