ML26021A080
| ML26021A080 | |
| Person / Time | |
|---|---|
| Site: | Hermes, 99902069 File:Kairos Power icon.png |
| Issue date: | 12/16/2025 |
| From: | NRC/NRR/DANU |
| To: | |
| References | |
| Download: ML26021A080 (0) | |
Text
QUESTIONS for 12/18/25 pre-submittal meeting
- 1. Flood Level Basis Please explain why the 10,000-year flood level of 763.1 ft msl is higher than the 25,000-year flood level of 759.9 ft msl. The slide indicates a 1.9-ft margin to grade and a 7.9-ft margin to the building slab with the updated flood level estimate. Do these margins remain adequate for lower-frequency flood events or for the probable maximum flood (PMF)?
- 2. Flood Design Category a) What is the trigger for the revised design basis flood analysis?
b) How is the Flood Design Category (FDC) defined? Please provide any applicable references for FDC. In addition, please justify the use of Flood Design Category 3 (FDC-3), or the 10,000-year flood, as the design basis. Are there any cliff edge effects for the lower than 10,000-year floods?
- 3. Impact of Increased Operating Life Hermes 2 PSAR Section 2.4 states that the proposed operating life has increased from 4 years (Hermes 1) to 11 years (Hermes 2). Are there any changes in total risk associated with this increase, particularly with respect to the higher design basis flood level (i.e., from 759.7 ft to 763.1 ft)?
- 4. Flood Frequency Analysis a) To support NRC staff understanding, please describe the calculation for the updated flood frequency analysis with a flood hazard curve, including associated uncertainty bounds, extending to a probability level of 1x10 to know a potential risk level.
b) Has the precipitation input changed in the revised analysis?
c) Has the model configuration changed in the revised analysis?