ML25069A632
| ML25069A632 | |
| 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: ML25069A632 (1) | |
Text
Response to NuScale Topical Report Audit Question Question Number: A-FSR.LTR-39 Receipt Date: 10/14/2024 Question:
Regarding Fuel Pellet Densification and Swelling and Clad Creep the analysis claims
[
] the guidance in NEI 12-16 R4 for not performing a detailed anaysis. [
] With respect to Clad OD NEI 12-16 Figure B-3 indicates Clad OD reaches a minimum at about 20 GWD/MTu, [
] With respect to Clad Thickness NEI 12-16 Figure B-4 indicates Clad Thickness initially increases reaching a maximum about 7.5 GWD/MTu and then decreases back to about the original at about 20 GWD/MTu and continues to decrease. By about 25 GWD/MTu the Clad Thickness is less than initially and continues to decrease. [
]
These indicate a difference between the applicants fuel design and that modeled in NEI 12-16 Appendix B and therefore the conclusions in NEI 12-16 may not be applicable to the applicant.
Explain the differences and justify why the NEI 12-16 R4 guidance is still applicable.
Response
The only significant deviation of the NuScale fuel behavior from the behavior reported in Appendix B of Nuclear Energy Institute (NEI) 12-16 is [
] The other parameters ([
]) exhibit similar trends.
[
] in the NuScale fuel is more conservative than the results presented in Appendix B of NEI 12-16.
NuScale Nonproprietary NuScale Nonproprietary
The most significant effect of fuel geometry change with irradiation is from [
] it is reasonable to expect that the conclusions reached in Appendix B of NEI 12-16, [W]hen all of the changes are looked at holistically, the overall impact of fuel geometry changes with depletion is small, and...fuel geometry changes with depletion do not need to be explicitly modeled in depletion calculations, are applicable to NuScale fuel.
No changes to the LTR are necessary.
NuScale Nonproprietary NuScale Nonproprietary