ML14126A388
| ML14126A388 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 05/20/2014 |
| From: | Farideh Saba Plant Licensing Branch II |
| To: | James Shea Tennessee Valley Authority |
| Saba F DORL/LPL2-2 301-415-1447 | |
| References | |
| TAC MF1185, TAC MF1186, TAC MF1187 | |
| Download: ML14126A388 (8) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 Mr. Joseph W. Shea Corporate Manager-Nuclear Licensing Tennessee Valley Authority 11 01 Market Street, LP 3D-C Chattanooga, TN 37402-2801 May 20, 2014
SUBJECT:
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)
Dear Mr. Shea:
By letter dated March 27, 2013, as supplemented by letter dated May 16, 2013, Tennessee Valley Authority (the licensee, TVA) submitted a license amendment request to transition the fire protection licensing basis at the Browns Ferry Nuclear Plant, Units 1, 2, and 3, from Title 10 of the Code of Federal Regulations (1 0 CFR), Appendix R to Section 50.48(c), National Fire Protection Association Standard (NFPA) 805, Performance-Based Standard for Fire Protection for Light Water Reactor Electric Generating Plants.
The current 1 0 CFR Part 50, Appendix R containment analysis for safe shutdown credits containment accident pressure (CAP) to ensure adequate net positive suction head for the residual heat removal pumps. In Attachment X of the letter dated March 27, 2013, as part of the transition to NFPA 805, the licensee proposed to eliminate the reliance on CAP credit. The Nuclear Regulatory Commission (NRC) staff has reviewed Attachment X and determined that additional information is needed to complete its review. On April17, 2014, the NRC staff forwarded, via an electronic mail, a draft of the request for additional information (RAI) to the TVA staff. On April29, 2014, the NRC staff and representatives of TVA held a conference call to provide the licensee with an opportunity to clarify any portion of the draft RAI and discuss the timeframe for which TVA may provide the requested information. The enclosure to this letter contains the finalized RAI. As a result of that conference call, the NRC staff and Jerry Jones of your staff agreed to June 13, 2014, for providing responses to the finalized RAI.
REQUEST FOR ADDITIONAL INFORMATION (RAI)
LICENSE AMENDMENT REQUEST TO ADOPT NATIONAL FIRE PROTECTION ASSOCIATION STANDARD 805 ATTACHMENT X TENNESSEE VALLEY AUTHORITY BROWNS FERRY NUCLEAR PLANT, UNITS 1, 2, AND 3 DOCKET NOS. 50-259, 50-260, AND 50-296 By letter dated March 27,2013 (Reference 1), Tennessee Valley Authority (TVA, the licensee) submitted a license amendment request for Browns Ferry Nuclear Plant (BFN), Units 1, 2, and 3, which proposes transition to Title 10 of the Code of Federal Regulations (1 0 CFR), Section 50.48(c)- NFPA 805, Performance-Based Standard for Fire Protection for Light Water Reactor Electric Generating Plants, 2001 Edition.
The current 10 CFR Part 50, Appendix R containment analysis for safe shutdown credits containment accident pressure (CAP) to ensure adequate net positive suction head (NPSH) for the residual heat removal (RHR) pumps. As part of the transition to NFPA 805, the licensee has proposed to eliminate the reliance on CAP credit. The licensee described the elimination of CAP credit in Attachment X (Reference 2) of the Reference 1. The Nuclear Regulatory Commission (NRC) staff has reviewed Attachment X and is requesting responses to the following items to complete its review.
SCVB1 RAI-1 The licensee in Attachment X,Section X.4 states:
Thermal performance testing of BFN Unit 3 RHR heat exchangers 3A and 3C was performed to determine the acceptability of the current four-year cleaning period and to substantiate the increase to 265 BTU/sec-°F [British Thermal Unit per second-degree Fahrenheit] utilizing the projected heat transfer at limiting conditions.
Please provide the following information:
(a)
Description of the performance test.
(b)
Measured value of the RHR heat exchanger (HX) fouling factor and the length of time from its previous maintenance cleaning.
(c)
Correlation (along with its reference) used to extrapolate and determine the worst fouling factor from the required cleaning time for maintaining the HX k-factor above 265 BTU/sec-°F.
1 Containment and Ventilation Branch (SCVB)
Enclosure (d)
Explain what is meant by "utilizing the projected heat transfer at limiting conditions."
(e)
What is the projected heat transfer value and its basis, and what are the limiting conditions?
SCVB RAI-2 The licensee in Attachment X,Section X.4 states:
A parametric evaluation of the RHR heat exchangers using a conservative fouling factor equivalent to 265 BTU/sec-°F was subsequently performed.
Provide the following information:
(a)
Description of the parametric evaluation of the RHR HXs.
(b)
How was the fouling factor equivalent to HX k-factor of 265 BTU/sec-°F determined, and how much was the conservatism in the fouling factor?
SCVB RAI-3 The licensee in Attachment X,Section X.4 states:
The k-factor for residual heat removal service water (RHRSW) temperature of 92 °F, 4400 gpm [gallons per minute] RHRSW flow, maximum tube plugging, and 7500 gpm RHR flow is approximately 284.5 BTU/sec-°F.
Provide the following information:
(a)
What is the value of the fouling factor that is used for calculating k-factor of 284.5 BTU/sec-°F?
(b)
What is the k-factor for a clean RHR HX with zero fouling and none of the tubes plugged?
(c)
Confirm that the maximum value of fouling factor is used in calculating k-factor of 284.5 BTU/sec-°F. If not, justify.
(d)
Confirm that 4400 gpm and 7500 gpm flows for RHRSW and RHR, respectively, are the most conservative values on which the k-factor of 284.5 BTU/sec-oF is based. Also, confirm that it will not be less than 284.5 BTU/sec-°F for any of the RHR operating modes.
Confirm that the k-factor of 284.5 BTU/sec-°F is based on conservative parameters and it will vary with input parameters or RHR operating modes. If not, justify.
SCVB-RAI-4 BFN Surveillance Requirement 3. 7.2.1 requires the average water temperature of ultimate heat sink to be less than or equal to 95 °F. Also, Reference 3, Enclosure 1, page E1-1 0, item c specifies the service water temperature to be 95 °F for containment analysis. Revise the NFPA 805 analysis using 95 °F as RHRSW temperature or provide justification for using 92 °F instead of 95 °F.
SCVB-RAI-5 The licensee in Attachment X,Section X.4 states:
Because thermal performance testing was performed on only two BFN Unit 3 RHR heat exchangers, the BFN Units 1, 2, and 3 RHR heat exchangers will be subject to a performance monitoring program to provide assurance that fouling that could affect the required heat transfer rate is detected and corrected in a timely manner. Therefore, TVA commits to revise the RHR heat exchanger performance monitoring program for the BFN Unit 1, 2, and 3 RHR heat exchangers to be consistent with the assumptions of the NFPA 805 NPSH, Containment Parameters, and AREVA Fuel PCT [peak cladding temperature}
Analysis calculation related to the RHR heat exchanger k-factor within 6 months following approval of this amendment request.
Describe the revised BFN Units 1, 2, and 3 RHR HXs performance monitoring program that will assure that fouling factor and tube plugging would not exceed their worst values assumed in calculating k-factor of 284.5 BTU/sec-°F.
SCVB RAI-6 The licensee in Attachment X does not clearly identify the computer code used for the NFPA 805 analysis. Describe the methodology, including the computer code used. Provide justification if there is a methodology change from the current licensing basis analysis methodology. Also, list any other changes {along with justifications) in input parameters and assumptions in the NFPA 805 analysis besides those listed in Tables 3 and 4 of Attachment X.
SCVB RAI-7 Provide the basis for selecting each of the three cases identified in Attachment X,Section X.5 for NFPA 805 containment analysis. Confirm that any other possible (or postulated) NFPA 805 analysis case that requires containment cooling will have acceptable NPSH margin for the pumps used.
SCVB RAI-8 The following table shows five input parameters extracted from Table 4 of Attachment X whose values are not consistent within the three cases and/or are different from those in Enclosure 1 of TVA letter dated April10, 2009, TVA (Reference 3). For example, initial wetwell airspace volume in Reference 3 is different from those in Cases 1, 2, and 3. However, initial drywell pressure for Cases 1 and 3 is not consistent with values in Case 2 and Reference 3. Justify the inconsistencies within the three analyzed cases and also with the values in Enclosure 1 of Reference 3, or revise the values to be consistent.
Parameter Cases 1 & 3 Case 2 Reference 3, Initial suppression pool volume 122,940 121,soo fe (page corresponding to minimum cubic feet 122,94o fe suppression pool level (fe)
E1-6, item 3.a.1)
Initial wetwell airspace volume 127,860 ft3 127,860 ft3 129,300 ft3 (page E1-7, item 3.c.2) 15.5 pound per square 17 psia (page E1-Initial drywell pressure
- inch, 17 psia 5, Item 2.b.6) absolute (psi a)
Initial drywell relative humidity 50%
20%
20% (page E 1-5, Item 2.d.5}
Initial wetwell pressure 14.4 psia 15.9 psia 15.9 psia (page E1-7, Item 3.d.6)
SCVB RAI-9 Referring to the parameters in SCVB RAI-8, explain how the following input parameters to the cases analyzed are conservative for minimizing the available NPSH for the RHR pumps.
(a) Initial suppression pool volume corresponding to minimum suppression pool level (b) Initial drywell pressure (c) Initial drywell temperature (d) Initial drywell relative humidity (e) Initial wetwell pressure (f) Initial wetwell temperature (g) Initial wetwell relative humidity SCVB RAI-10 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.
REFERENCES
- 1.
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)"
(NRC Agencywide Documents Access and Management System (ADAMS) Accession No. ML13092A393).
- 2.
Tennessee Valley Authority Browns Ferry Nuclear Plant, Units 1, 2 and 3, "Transition to 10 CFR 50.48(c)- NFPA 805 Performance-Based Standard for Fire Protection for Light Water Reactor Electric Generating Plants, 2001 Edition, Attachment X-Elimination of Containment Accident Pressure Credit" (ADAMS Accession No. ML13092A392).
- 3.
Letter from TVA to NRC dated April10, 2009, "Browns Ferry Nuclear Plant (BFN)-
Units 1, 2, And 3-Technical Specifications (TS) Changes TS-431 and TS-418 - Extended Power Uprate (EPU) -Transmittal of Containment Parameters and Total Shutdown Power Fractions (TAC Nos. MD5262, MD5263, and MD5264)" (ADAMS Accession No. ML091060381).
J.Shea Please contact me at 301-415-1447, or via email at farideh.saba@nrc.gov, if you have any questions.
Sincerely, IRA by AHon for/
Farideh E. Saba, Senior Project Manager Plant Licensing Branch 11-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-259, 50-260, and 50-296
Enclosure:
Request for Additional Information cc w/enclosures: Distribution via Listserv DISTRIBUTION:
PUBLIC LPL2-2 r/f RidsNrrDorllpl2-2 RidsNrrPMBrownsFerry RidsN rrLABCiayton RidsN rrDssScvb RidsAcrsAcnw_MaiiCTR RidsNrrDoriDpr RidsRgn2MaiiCenter JRobinson, NRR SWall, NRR ASallman, NRR BMiller, NRR A DAMS Accession o.:
141 N
ML 26A388
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OFFICE LPLII-2/PM LPLII-2/LA SCVB/BC*
LPLII-2/BC(A)
LPLII-2/PM NAME FSaba BCiayton RDennig LRegner FSaba (AHon for)
DATE 05/15/14 05/07/14 04/07/14 05/20/14 05/20/14 OFFICIAL RECORD COPY