CNL-14-116, Response to NRC Request for Additional Information Regarding the License Amendment Request to Adopt National Fire Protection Association 805 Performance-Based Standard for Fire Protection for Light Water Reactor
| ML14192B044 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 07/10/2014 |
| From: | James Shea Tennessee Valley Authority |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| CNL-14-116, L44 140710 002, TAC MF1185, TAC MF1186, TAC MF1187 | |
| Download: ML14192B044 (4) | |
Text
L44 140710 002 1101 Market Street, Chattanooga, Tennessee 37 402 CNL-14-116 July 10, 2014 10 CFR 50.90 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555-0001 Browns Ferry Nuclear Plant, Units 1, 2, and 3 Renewed Facility Operating License Nos. DPR-33, DPR-52, and DPR-68 NRC Docket Nos. 50-259 , 50-260 , and 50-296
Subject:
Response to the Nuclear Regulatory Commission's (NRC) Request for Additional Information Regarding the License Amendment Request to Adopt National Fire Protection Association 805 Performance-Based Standard for Fire Protection for Light Water Reactor Electric Generating Plants for the Browns Ferry Nuclear Plant, Units 1, 2, and 3 (TAC Nos.
MF1185, MF1186, and MF1187)- Attachment X (second set)
References:
- 1. Letter from Tennessee Valley Authority (TVA) to NRC, "License Amendment Request to Adopt NFPA 805 Performance-Based Standard for Fire Protection for Light Water Reactor Electric Generating Plants (2001 Edition) (Technical Specification Change TS-480) ," dated March 27 , 2013 (ADAMS Accession No. ML13092A393)
- 2. Letter from TVA to NRC , "Response to NRC Request to Supplement License Amendment Request to Adopt NFPA 805 Performance-Based Standard for Fire Protection for Light Water Reactor Electric Generating Plants for the Browns Ferry Nuclear Plant, Units 1, 2, and 3 (TAC Nos.
MF1185, MF1186, and MF1187) ," dated May 16, 2013 (ADAMS Accession No. ML13141A291)
- 3. Letter from NRC to TVA, "Browns Ferry Nuclear Plant, Units 1, 2, and 3-Request for Additional Information Regarding Attachment X Of License Amendment Request to Adopt National Fire Protection Association Standard 805, Performance-Based Standard for Fire Protection for Light Water Reactor Generating Plants (TAC Nos. MF1185, MF1186, and MF1187)," dated May 20, 2014 (ADAMS Accession No. ML14126A388)
- 4. Letter from TVA to NRC, "Response to NRC Request for Additional Information Regarding the License Amendment Request to Adopt NFPA 805 Performance-Based Standard for Fire Protection for Light Water Reactor Electric Generating Plants for the Browns Ferry Nuclear Plant, Units 1, 2, and 3 (TAC Nos. MF1185, MF1186, and MF1187)-
Attachment X and Fire Modeling ," dated June 13, 2014 (ADAMS Accession No. ML)
U.S. Nuclear Regulatory Commission Page 2 July 10, 2014 By letter dated March 27, 2013 (Reference 1), Tennessee Valley Authority (TVA) submitted a license amendment request (LAR) for Browns Ferry Nuclear Plant (BFN), Units 1, 2, and 3, to transition to National Fire Protection Association Standard (NFPA) 805 Performance-Based Standard for Fire Protection for Light Water Reactor Electric Generating Plants. In addition, by letter dated May 16, 2013 (Reference 2), TVA provided information to supplement the Reference 1 letter.
By letter dated May 20, 2014 (Reference 3), the Nuclear Regulatory Commission (NRC) requested additional information related to the LAR Attachment X to support the review of the LAR. The required due date for the responses to this request for additional information (RAI) was June 13, 2014. The TVA response to the questions in the Reference 3 RAI was provided by letter dated June 13, 2014 (Reference 4), with the exception of Containment and Ventilation Branch (SCVB) RAI 10. The due date for this RAI question was extended to July 11 , 2014, as discussed in a teleconference between the NRC and TVA on June 5, 2014. The enclosure to this letter provides the TVA response to SCVB RAI question 10.
Consistent with the standards set forth in Title 10 of the Code of Federal Regulations (10 CFR), Part 50.92(c), TVA has determined that the additional information, as provided in this letter, does not affect the no significant hazards consideration associated with the proposed application previously provided in Reference 1.
There are no new regulatory commitments contained in this submittal. Please address any questions regarding this submittal to Mr. Edward D. Schrull at (423) 751-3850.
I declare under penalty of perjury that the foregoing is true and correct. Executed on this 10th day of July 2014.
Respectfully,
~~:uclea: Licensing
Enclosure:
TVA Response to NRC Request for Additional Information - Attachment X, SCVB RAI10 cc (Enclosure):
NRC Regional Administrator- Region II NRC Senior Resident Inspector- Browns Ferry Nuclear Plant NRC Project Manager - Browns Ferry Nuclear Plant State Health Officer, Alabama State Department of Health
ENCLOSURE Tennessee Valley Authority Browns Ferry Nuclear Plant, Units 1, 2, and 3 TVA Response to NRC Request for Additional Information- Attachment X, SCVB RAI10 Containment and Ventilation Branch (SCVB) RAI-1 0 Confirm that the heat transfer coefficients and heat sinks modelled in the NFPA 805 analysis cases are the same as in the current licensing basis Appendix R analysis. Provide justification in case the conservatism is reduced in the NFPA 805 analysis.
RESPONSE
The primary containment analysis for the current licensing basis Appendix R analysis and the NFPA 805 analysis were both performed by General Electric Hitachi (GEH) using the BFN SHEX model. The Appendix R analysis for Unit 1 restart was provided to the NRC in a submittal dated August 31 , 2006 (Reference 1). This analysis formed the basis for NRC approval of the Appendix R event for Unit 1 restart. The NFPA 805 primary containment analysis cases cited in the NFPA 805 License Amendment Request (Reference 2) were completed in September 2012.
The BFN primary containment modeling was reviewed by GEH to identify changes as requested in this RAI. Based on that review, TVA provides the following confirmation statements. The heat sinks in the drywell, the wetwell, and the suppression pool are modeled.
There are no differences in the primary containment heat sinks between the current licensing basis Appendix R analysis and the NFPA 805 analysis. The heat transfer coefficients in this request for information are the heat transfer coefficients between the primary containment heat sinks and their surroundings, and between the wetwell airspace and the suppression pool. The heat transfer coefficients are not changed between the current licensing basis Appendix R analysis and the NFPA 805 analysis. For the heat transfer associated with the heat sinks to the airspaces in both the drywell and the wetwell, the heat transfer mode and magnitude are determined by SHEX, depending on the thermal dynamic conditions in the airspaces and in the heat sinks. The method for modeling the heat transfer between the heat sinks and their surroundings are not changed in SHEX for the Appendix R analysis and the NFPA 805 analysis.
In addition , two changes have been made to the SHEX primary containment model other than heat transfer coefficients and heat sinks that are related to the primary containment temperature response. These model changes are included in the NFPA 805 analysis and are discussed below.
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Drywell Cooler Operation In the Appendix R SHEX analysis for Unit 1 restart, the drywell coolers were assumed to operate for the first 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> of the event. This assumption was made to minimize the primary containment back pressure contribution to the available net positive suction head (NPSHa) for the Residual Heat Removal (RHR) system pumps. The NFPA 805 SHEX analyses assume that the drywell coolers are not operating. However, because credit is not taken for Containment Accident Pressure (CAP) in the NFPA 805 NPSH analysis, drywell cooler operation on containment pressure does not affect the calculated RHR pump NPSHa. This assumption is conservative with respect to the NFPA 805 NPSH analysis because drywell cooler operation removes heat from containment and a higher suppression pool temperature is realized if the drywell coolers are not assumed to be in service.
Drywell Heat Load Modeling of the Control Rod Drive System piping containment heat source for the short-term time period following the reactor scram (i.e. , 0-30 minutes) was changed to reduce the calculated heat input from the primary system to the drywell air space. This SHEX analysis was performed by GEH to better model drywell temperature response and does not have a significant effect on suppression pool temperature. Because credit is not taken for CAP in the NFPA 805 NPSH analysis, effects on containment pressure resulting from the drywell air space temperature model change do not affect the calculated RHR pump NPSHa.
REFERENCES
- 1. Letter from TVA to NRC dated August 31, 2006, "Browns Ferry Nuclear Plant- Units 1, 2, and 3- Extended Power Uprate- Technical Specifications Changes TS-431 and TS-418-Replacement Documentation" (ADAMS Accession Number ML062510371)
- 2. Letter from TVA to NRC dated March 27, 2013, "License Amendment Request to Adopt NFPA 805 Performance-Based Standard for Fire Protection for Light Water Reactor Electric Generating Plants (2001 Edition) (Technical Specification Change TS-480)"
(ADAMS Accession No ML13092A393)
E-2