CP-201600078, Submittal of Request for Additional Information Re Fukushima Lessons Learned - Flooding Hazard Reanalysis Report
| ML16041A029 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 02/03/2016 |
| From: | Thomas McCool, Peters K Luminant Generation Co, Luminant Power |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| CP-201600078, EA-12-049, TAC MF1099, TAC MF1100, TXX-16015 | |
| Download: ML16041A029 (3) | |
Text
Kenneth J. Peters Luminant Power Senior Vice President P O Box 1002
& Chief Nuclear Officer (Acting) 6322 North FM 56 Kenneth.Peters@luminant.com Glen Rose, TX 76043 T 254 897 6565 C 817 776 0037 F 254 897 6652 CP-201600078 REF 10 CFR 50.54(f)
Log # TXX-16015 February 3, 2016 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555-0001
SUBJECT:
Comanche Peak Nuclear Power Plant, Docket Nos. 50-445 And 50-446, Submittal of Request for Additional Information Regarding Fukushima Lessons Learned - Flooding Hazard Reanalysis Report (TAC NOS. MF1099 and MF1100)
REFERENCES:
- 1. Luminant Generation Company LLCs Letter TXX-13053, Response to March 12, 2012, Request for Information Enclosure 2, Recommendation 2.1, Flooding Hazard Reevaluation Report, of the Near-Term Task Force Review of Insights from the Fukushima Dai-Ichi Accident, dated March 12, 2013, Accession No. ML13074A058
- 2. NRC Letter, Request for Additional Information Regarding Fukushima Lessons Learned - Flooding Hazard Reanalysis Report, dated March 7, 2014, Accession No. ML14059A188
- 3. Luminant Generation Company LLCs Letter TXX-14048, Submittal of Requested Information Regarding Fukushima Lessons Learned - Flooding Hazard Reanalysis Report dated April 4, 2014, Accession No. ML14100A049
- 4. Luminant Generation Company LLCs Letter TXX-14094, Submittal of Fukushima Lessons Learned - Flood Hazard Reevaluation Report Supplement 1 dated August 14, 2014, Accession No. ML14245A136
- 5. Luminant Generation Company LLCs Letter TXX-15111, Submittal of Requested Information Regarding Fukushima Lessons Learned - Flood Hazard Reevaluation Report, dated September 22, 2015
Dear Sir or Madam:
On March 12, 2013, Luminant Generation Company LLC (Luminant Power) submitted Comanche Peak Nuclear Power Plants (CPNPP) Flooding Hazard Reevaluation Report (Reference 1). References 3, 4, and 5 submitted additional information to the NRC in response to Reference 2. As a result of additional communications between the NRC staff (Victor Hall, et. al.) and Luminant Power (Carl Corbin, et. al) during a flooding audit conference call on January 20, 2016, Luminant Power agreed to use the conditions and assumptions described in the attachment to this letter for performing the CPNPP Mitigating Strategies Assessment.
U. S. Nuclear Regulatory Commission TXX-16015 Page 2. of 2.
02./0312.016 This letter contains one new regulatory commitment.
Number Commitment Due Date/Event 5220609 Luminant Power agrees to use flood parameters / In accordance assumptions identified in the attachment to TXX-16015 to with NRC complete the Mitigating Sh-ategies Assessment. schedule If there are any questions regarding this plan, please contact Mr. Carl B. Corbin at (254) 897-0121 carl.corbin@luminant.com.
I state under penalty of perjury that the foregoing is true and correct.
Executed on February 3, 2016.
Sincerely, Luminant Generation Company LLC Kenneth J. Peters Thomas P. McCool Site Vice President (Acting)
Attachment c- William M. Dean, Director, Office of Nuclear Reactor Regulation Marc L. Dapas, Region IV Balwant K. Singal, NRR Victor Hall, NRR Stephen A. Monarque, NRR Resident Inspectors, Comanche Peak
Attachment to TXX-16015 Page 1 of 1 As a result of additional communications between the NRC staff (Victor Hall, et. al.) and Luminant Power (Carl Corbin, et. al) during a flooding audit conference call on January 20, 2016, Luminant Power agreed to use the conditions and assumptions described below for Comanche Peak Nuclear Power Plant (CPNPP) Units 1 and 2.
Flood Parameters and Assumptions for Mitigating Strategies Assessment (MSA)
- 1. Appendix G of NEI 12-06 Rev 2 to be used to perform the Mitigating Strategies Assessment as endorsed by JLD-ISG-2012-01, Revision 1, Compliance with Order EA-12-049, Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events (ML16020A087 and ML15357A163).
- 2. Controlling Flood Parameters
- a. Flood Height - The peak Local Intense Precipitation (LIP) flood height would be 810.6 mean sea level (msl) immediately adjacent to structures (safety related or non-safety related as listed in Table 2-1-3 of Attachment to TXX-15111) that have an entrance elevation of 810.5 msl or lower (based on NRC request to evaluate the consequences of a value higher than 810.5 msl, which is the entrance height to several structures). The purpose is to identify entrance paths in the plant and assess the impact on flex mitigation strategies. The impact on the current design basis will not be assessed. Hydrographs derived from current HEC-RAS analysis of record previously submitted under Reference 5 (TXX-15111 dated September 22, 2015) will be scaled up to a peak of 810.6 msl for catch basins adjacent to entrances to structures as noted above.
- b. Flood event duration - LIP Flood duration to be based on same shape of existing hydrograph profiles scaled as noted in item 2.a (i.e., front loaded, transient in nature, and short duration)
- c. Relevant associated effects (e.g., wind driven waves and run-up effects, hydrodynamic loading including debris, sedimentation and erosion, etc.) - This is not applicable for CPNPP.
- d. Warning time and flood event transient surface elevations - It is anticipated that warning time will not be applicable, but NEI-15-05 Warning Time for Local Intense Precipitation Events may be used depending on the assessment of items 2.a and 2.b above.
- 3. In the sequence of events for the FLEX strategies, the time when the Extended Loss of AC Power (ELAP) / Loss of Normal Access to the Ultimate Heat Sink (LUHS) is assumed to occur will be specified and a basis provided during the MSA.
- 4. As needed, physical changes to mitigate or prevent flood water entry into structures will be considered (e.g., increase height of ramp entry on west side of Turbine Building).
- 5. Realistic qualitative arguments will consider conservative assumptions in existing analysis (e.g.,
no sheet flow off roof, credit gravel voids)
- 6. Luminant Power is currently in the process of developing a site specific Probable Maximum Precipitation (PMP) and may potentially use the results of that effort in qualitative arguments.
- 7. The Assumption of a peak LIP elevation of 810.6 ft msl is only for use in MSA. Operability and reportability of the current design basis is not impacted. Additionally, the appropriate flood parameters for use in the focused LIP evaluation will be identified as part of that evaluation.
Luminant Power does not commit at this time to use the elevation 810.6 ft msl for any part of the focused LIP evaluation.