ML25069A643
| ML25069A643 | |
| Person / Time | |
|---|---|
| Site: | 05200050 |
| Issue date: | 03/10/2025 |
| From: | NuScale |
| To: | Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML25069A609 | List: |
| References | |
| LO-180139 | |
| Download: ML25069A643 (1) | |
Text
Response to NuScale Topical Report Audit Question Question Number: A-FSR.LTR-47 Receipt Date: 10/14/2024 Question:
Section 6.5.6: Damaged Fuel Assembly states, The SFRs are designed to store up to [
]
damaged FAs.
Section 6.6.5.2 states, Thus, a fresh FA loaded into a Zone 2 location may have damaged cladding with no additional restriction on number or location of damaged assemblies. Clarify this apparent discrepancy.
Response
Section 6.6.5.2, Damaged Fuel Assemblies, describes that the criticality analysis assumes all fresh fuel assemblies (FAs) are flooded with water (i.e., damaged). Fresh FAs are restricted to storage in Zone 2 locations. Therefore, the spent fuel racks (SFRs) are designed with all Zone 2 locations containing damaged fresh fuel.
The statement in Section 6.5.6 that the SFRs are designed to store up to [
] damaged FAs describes a design specification. In order to accommodate this design specification, the SFRs were designed as described above, to store damaged FAs in all Zone 2 locations (simultaneously), allowing the licensee flexibility. To avoid confusion about restrictions on the storage of damaged FAs, NuScale has removed the statement from Section 6.5.6.
Markups of the affected changes, as described in the response, are provided below:
NuScale Nonproprietary NuScale Nonproprietary
NuScale US460 Fuel Storage Rack Design Topical Report TR-145417-NP Draft Revision 1
© Copyright 2025 by NuScale Power, LLC 197 Thus, fuel enriched to [
] wt.% 235U or less may be placed anywhere in the FSRs without limitation.
6.5.6 Damaged Fuel Assembly Audit Question A-FSR.LTR-47 The SFRs are designed to store up to [
] damaged FAs. For this analysis a damaged FA is assumed to be discharged to the spent fuel pool before achieving a burnup that allows storage in Zone 1. Damaged FAs are conservatively assumed to be new FAs and must be placed in Zone 2 locations.
6.5.7 Assembly Dropped on Top of Rack An FA dropped on the top of the rack deforms the upper grid structure by less than
[
] The distance from the assembly on top of the rack to an assembly correctly stored in the rack is approximately [
] accounting for deformation. Section 6.3.1 of NEI 12-16 revision 4 states that a separation of 12 inches is sufficient to prevent neutronic coupling to the dropped assembly.
Figure 6-36 Final Burnup versus Enrichment Limit for Zone 1
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]