ML25254A232
| ML25254A232 | |
| Person / Time | |
|---|---|
| Site: | 07201032 |
| Issue date: | 09/11/2025 |
| From: | Holtec |
| To: | Office of Nuclear Material Safety and Safeguards |
| Shared Package | |
| ML25254A228 | List: |
| References | |
| 5018126 | |
| Download: ML25254A232 (1) | |
Text
SFSC Heat Removal System B 3.1.2 HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL REPORT HI-2114830 Proposed Rev. 11E 13.A-18 BASES LCO The SFSC Heat Removal System must be verified to be operable to preserve the assumptions of the thermal analyses. Operability is defined as at least 50% or more of each of the inlet and outlet air ductsvent areas unblocked and available for air flow (i.e.,
unblocked). As discussed in Subsection 4.6.1.3 of the FSAR, the effect of partially blocked outlet vents is similar to the effect of partially blocked inlet vents. The resulting decrease in flow area increases the flow resistance of the inlet and outlet ducts, thereby decreasing the air mass flow rate into the system. Operability of the heat removal system ensures that the decay heat generated by the stored fuel assemblies is transferred to the environs at a sufficient rate to maintain fuel cladding and other SFSC component temperatures within design limits.
For the HI-STORM FW Extended Configuration the SFSC Heat Removal System shall remain operable. Operability is defined as 50% or more of each of the inlet and outlet vent areas unblocked and available for flow. A higher blockage of inlet vents in the upper cask in the Extended Configuration is acceptable for as long as the percentage amount of blockage is equivalently lower in the lower cask i.e., a 75% blockage of upper inlet vent areas combined with 25% blockage of lower inlet vent areas is acceptable.
The intent of this LCO is to address those occurrences of air duct blockage that can be reasonably anticipated to occur from time to time at the ISFSI (i.e., Design Event I and II class events per ANSI/ANS-57.9). These events are of the type where corrective actions can usually be accomplished within one 8-hour operating shift to restore the heat removal system to operable status (e.g.,
removal of loose debris).
This LCO is not intended to address low frequency, unexpected Design Event III and IV class events (ANSI/ANS-57.9) such as design basis accidents and extreme environmental phenomena that could potentially block one or more of the air ducts for an extended period of time (i.e., longer than the total Completion Time of the LCO). This class of events is addressed site-specifically as required by Section 3.4.10 of Appendix B to the CoC.
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