ML073230348
| ML073230348 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 11/15/2007 |
| From: | Emens J Tennessee Valley Authority |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| TVA-BFN-TS-418, TVA-BFN-TS-431 | |
| Download: ML073230348 (35) | |
Text
November 15, 2007 TVA-BFN-TS-418 TVA-BFN-TS-431 10 CFR 50.90 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Mail Stop OWFN, P1-35 Washington, D. C. 20555-0001 Gentlemen:
In the Matter of
)
Docket Nos. 50-259 Tennessee Valley Authority )
50-260 50-296 BROWNS FERRY NUCLEAR PLANT (BFN) - UNITS 1, 2, AND 3 -
TECHNICAL SPECIFICATIONS (TS) CHANGES TS-431 AND TS-418 -
EXTENDED POWER UPRATE (EPU) - RESPONSE TO ROUND 13 REQUEST FOR ADDITIONAL INFORMATION (RAI) - CONTAINMENT OVERPRESSURE APLA-35/37 By letters dated June 28, 2004 (ADAMS Accession No. ML041840109) and June 25, 2004 (ML041840301), TVA submitted license amendment applications for EPU of BFN Unit 1 and BFN Units 2 and 3, respectively. On July 5, 2007, the NRC staff issued a Round 13 RAI (ML071780190) regarding the EPU license amendment requests. The Round 13 RAI contains a set of APLA RAIs (containment overpressure) and seven SBWB RAIs. TVA's responses to the Round 13 SBWB RAI items were submitted on August 9, 2007 (ML072270037). TVAs responses to all but one of the Round 13 containment overpressure RAI items were submitted on August 31, 2007 (ML072480547). The enclosure to this letter provides the response to the remaining RAI (APLA-35/37).
U.S. Nuclear Regulatory Commission Page 2 November 15, 2007 TVA has determined that the additional information provided by this letter does not affect the no significant hazards considerations associated with the proposed TS changes. The proposed TS changes still qualify for a categorical exclusion from environmental review pursuant to the provisions of 10 CFR 51.22(c)(9).
No new regulatory commitments are made in this submittal. If you have any questions regarding this letter, please contact me at (256)729-3612.
I declare under penalty of perjury that the foregoing is true and correct. Executed on this 15th day of November, 2007.
Sincerely, Original signed by:
James E. Emens, Acting Manager of Licensing and Industry Affairs
Enclosure:
Response to Round 13 Request For Additional Information -
Containment Overpressure APLA-35/37
U.S. Nuclear Regulatory Commission Page 3 November 15, 2007 Enclosure cc (Enclosure):
State Health Officer Alabama State Department of Public Health RSA Tower - Administration Suite 1552 P.O. Box 303017 Montgomery, Alabama 36130-3017 NRC Senior Resident Inspector Browns Ferry Nuclear Plant 10833 Shaw Road Athens, AL 35611-6970 Branch Chief U.S. Nuclear Regulatory Commission Region II Sam Nunn Atlanta Federal Center 61 Forsyth Street, SW, Suite 23T85 Atlanta, Georgia 30303-8931 Eva Brown, Project Manager U.S. Nuclear Regulatory Commission (MS 08G9)
One White Flint, North 11555 Rockville Pike Rockville, Maryland 20852-2739
U.S. Nuclear Regulatory Commission Page 4 November 15, 2007 DAH:BAB Enclosure Cc (Enclosure)
G. Arent, EQB 1B.-WBN R. H. Bryan, Jr., LP 4J-C W. R. Campbell, Jr. LP 3R-C S. M. Douglas, POB 2C-BFN R. G. Jones, POB 2C-BFN R. F. Marks, Jr., PAB 1C-BFN D. C. Matherly, BFT 2A-BFN L. E. Nicholson, BR 4X-C B. A. Wetzel, BR 4X-C B. J. OGrady, PAB 1E-BFN S. A. Vance, WT 6A-K E. J. Vigluicci, ET 11A-K NSRB Support, LP 5M-C EDMS WT CA-K, S:Lic/submit/subs/EPU/round 13 Ts 431-418.doc
E-1 ENCLOSURE TENNESSEE VALLEY AUTHORITY BROWNS FERRY NUCLEAR PLANT (BFN)
UNITS 1, 2, AND 3 TECHNICAL SPECIFICATIONS (TS) CHANGES TS-431 AND TS-418 EXTENDED POWER UPRATE (EPU)
RESPONSE TO ROUND 13 REQUEST FOR ADDITIONAL INFORMATION (RAI)
CONTAINMENT OVERPRESSURE APLA-35/37 NRC Request APLA-35/37 Discuss whether the fire risk evaluation contained in the IPEEE addresses spurious actuations (hot shorts) of the containment isolation valves or the need for the COP credit. If not, address the change in risk considering COP and submit a summary of the updated results.
TVA Reply to APLA-35/37 Current Analyses As previously identified by the NRC in the closeout of Generic Letter 88-20, Supplement 4, "Individual Plant Examination of External Events (IPEEE) for Severe Accident Vulnerabilities" for BFN Unit 1 dated June 28, 2007 (ADAMS Accession No. ML071790196), the BFN IPEEE does not assess post-fire safe shutdown circuit analysis spurious actuations. The NRC staff and industry are developing an approach to evaluate this generic issue.
The response to RAI question APLA-24/26 in TVA letter dated July 21, 2006 (ML062090071) provided a qualitative evaluation of the risk associated with the need for containment overpressure (COP) for postulated fires. In contrast to the realistic approach discussed in the July 21, 2006, response, the rule-based Appendix R analysis is a bounding analysis based on worst case conditions. The Appendix R evaluation is based on prescriptive deterministic evaluations using conservative inputs and assumptions that results in a minimum complement of available safe shutdown system (SSDS) equipment. The minimum SSDS includes the equipment necessary for the alternate shutdown
E-2 cooling mode with one Residual Heat Removal (RHR) system pump.
Based on these worst case conditions, the analysis for Appendix R shows that credit for COP is needed to ensure adequate net positive suction head (NPSH) for the RHR pump operating in alternate shutdown cooling mode.
Realistic Fire Evaluation To further address this RAI, TVA has performed additional evaluations to qualify the risk associated with spurious actuations of the containment isolation valves for fires that could require COP. These evaluations are based on realistic determinations of the likelihood of fire events of the magnitude necessary to cause damage defined by the worst case Appendix R conditions and include consideration of the plant equipment and procedures that would be available to ensure safe shutdown of the plant. Additionally, for those fire events which could require COP, an evaluation of potential equipment damage was performed to address the potential of spurious actuations of containment isolation valves that could affect COP.
Fire Hazards Analysis The BFN fire protection program includes formal calculations and specific safe-shutdown instructions (SSI) which demonstrate compliance with rule-based Appendix R requirements. To support a realistic fire evaluation, a fire hazards analysis of the 39 BFN fire areas defined by the fire protection program was performed. This analysis was based on a review of the specific characteristics of the fire areas to determine which areas could be expected to involve a fire with damage commensurate with that defined by the rule-based Appendix R analysis.
Characteristics of the fire areas that were reviewed included combustible loading, ignition sources, room geometry, and available automatic detection and suppression equipment.
Based on this analysis, 23 of the 39 fire areas were judged not to have the potential for the occurrence of a fire which could extensively involve secondary combustibles.
Therefore, it is not necessary to further analyze the impact on plant equipment for these fire areas in the realistic fire evaluation.
The fire area that includes the BFN control rooms (fire area 16) was also included for further evaluation for conservatism. Therefore, a total of 17 fire areas were
E-3 included in the evaluations below. Table APLA-35/37.1 provides a summary of the fire hazards analysis.
Equipment Availability The rule-based Appendix R analysis is based on worst case conditions that rely upon only the minimum SSDS (alternate shutdown cooling mode with one RHR pump). However, in many fire events, more equipment than this minimum would be available and used by the operating crew to safely shutdown and cool the reactor. For example, balance of plant (BOP) equipment, such as condensate/feedwater systems and the main condenser, and the high pressure coolant injection (HPCI) system would be available in many fire events and utilized instead of the alternate shutdown cooling mode.
An assessment was performed to determine equipment availability for fire events in the 17 fire areas identified in the fire hazards analysis. Based on the equipment availability, an operational response for each affected fire area was determined. Response to the fire events considered actions in plant procedures such as the Emergency Operating Instructions (EOI) as opposed to entry into the SSIs as is assumed in the worst case. This assessment determined that the use of available equipment and systems would avoid the need to initiate the alternate shutdown cooling mode with one RHR pump. The results of this assessment are provided in Table APLA-35/37.2.
The response for these 17 fire areas as they relate to COP is summarized as follows.
- For 10 of the 17 fire areas, the main condenser would be available as the heat sink. In these cases, COP is not needed.
- For five fire areas (05, 08, 13, 16, & 25 TB), the main condenser would not be available as the heat sink; however, two RHR pumps would be available for suppression pool cooling. As discussed previously in the response to RAI question APLA-24/26 in TVA letter dated July 21, 2006, using two or more RHR pumps and associated Residual Heat Removal Service Water (RHRSW) system pumps in the suppression pool cooling mode of operation maintains suppression pool temperature low enough that COP is not required.
- For two fire areas (04 & 09), the main condenser would not be available as the heat sink and only one RHR
E-4 pump would be available for suppression pool cooling.
COP may be required to provide adequate NPSH for the single RHR pump during warm weather conditions; however COP would not be needed to support core cooling since this would be provided by other systems that do not rely upon the suppression pool. The realistic fire scenario eliminates the defense in depth issue associated with the licensing basis Appendix R analysis in which core cooling relies on the pressure boundary integrity of the containment.
In support of this RAI response, TVA has identified minor changes to procedures that will be made to improve the response to fire events at BFN.
Spurious Actuation of Containment Isolation Valves The two fire areas (04 & 09) in which COP would be needed for fire events were additionally reviewed to determine if any containment isolation circuitry would be affected by a fire in that area. This review examined primary containment penetrations which connect the drywell or torus airspace inside containment with an open (e.g.,
ventilation) system outside containment. Failure to close or spurious opening of isolation valves in such process lines could result in the depressurization of primary containment.
This review concluded that none of the containment isolation valve cables that could cause spurious opening (downstream of the main control room hand switches) are located in these two fire areas. Therefore, spurious actuations (hot shorts) of containment isolation valves would not be a consideration for these two fire areas.
Conclusion A realistic evaluation of fire areas at BFN indicates that fire events in only two fire areas would result in conditions that could require the need for COP. In these cases, COP would not be needed to support core cooling but would be needed for the RHR pump aligned for suppression pool cooling (eliminating the dependence of core cooling on containment integrity). The two associated fire areas do not contain circuitry that would affect containment isolation valves capability. Based on these evaluations, the risk associated with spurious actuations (hot shorts) of the containment isolation valves for Appendix R fires is considered to be not significant.
Table APLA-35/37.1 BFN Fire Area Evaluation E-5 Fire Area/Zone Location Description Realistic Fire Evaluation Extensive Secondary Combustible Involvement (Y/N) 01-01 U1 Reactor Bldg, EL 519 -- EL 565 from Col. R1 to 10 ft. East of Col. R4 The significant ignition sources of the electrical boards on the 565 elevation are separated from each other by large distances over a large area with a high ceiling. Area wide detection coverage and area wide automatic suppression coverage are provided over the entire 565 elevation. The ignition sources on the 519 elevation are located in corner rooms and are separated from the each other by large distances over a large area and a wall separates the HPCI pump from other areas.
The HPCI area is protected by detection and automatic suppression. The other pumps areas have detection but no suppression. With the area wide detection coverage and area wide automatic suppression coverage over the electrical boards, there are no credible fire scenarios with the potential for extensive involvement of secondary combustibles.
N
Table APLA-35/37.1 BFN Fire Area Evaluation E-6 Fire Area/Zone Location Description Realistic Fire Evaluation Extensive Secondary Combustible Involvement (Y/N) 01-02 U1 Reactor Bldg, EL 519 - 565, from Col R7 to 10 ft.
west of Col. R4 and Southeast Stairway/
Elevator Enclosure between Cols. R6 to R7 at EL 593, 621 and 639.
There are no significant ignition sources on the 565 elevation. Area wide detection coverage and area wide automatic suppression coverage are provided over the entire 565 elevation. The ignition sources on the 519 elevation are located in corner rooms and are separated from the each other by large distances over a large area. The pumps areas have detection but no suppression. With the area wide detection coverage and area wide coverage over the 565 elevation, there are no credible fire scenarios with the potential to extensively involve secondary combustibles.
N 01-03 U1 Reactor Bldg, EL 593, north of Col. R.
There are no significant ignition sources on the 593 elevation. Area wide detection coverage and area wide automatic suppression coverage is provided over the entire 593 elevation. The single pump area is protected by area wide detection and automatic suppression. These pumps do not present significant ignition sources due to lack of combustible material present. With the area wide detection coverage and area wide suppression coverage over the 593 elevation, there are no credible fire scenarios with the potential to extensively involve secondary combustibles.
N
Table APLA-35/37.1 BFN Fire Area Evaluation E-7 Fire Area/Zone Location Description Realistic Fire Evaluation Extensive Secondary Combustible Involvement (Y/N) 01-04 U1 Reactor Bldg, EL 593 south of column line Q and RHR Heat Exchanger Rooms, EL 565 and 593.
There are no significant ignition sources on the 593 elevation. Area wide detection coverage and area wide automatic suppression coverage are provided over the entire 593 elevation. The pumps areas are protected by area wide detection and automatic suppression. These pumps do not present significant ignition sources due to lack of combustible material present. With the area wide detection coverage and area wide suppression coverage over the 593 elevation, there are no credible fire scenarios with the potential to extensively involve secondary combustibles.
N 01-05 U1 Reactor Bldg on EL 621 and EL 639 north of Col.
line R The significant ignition sources of the electrical boards, transformers and pumps on the 621 elevation are separated from the each other and spread over a large area. Area wide detection coverage and area wide automatic suppression coverage are provided over the entire 621 elevation. The Standby Liquid Control (SLC) pumps area on the north 639 elevation has detection, but no suppression. These pumps do not present significant ignition sources due to lack of combustible material present. With the area wide detection coverage and area wide automatic suppression coverage over the significant ignition sources, there are no credible fire scenarios with the potential to extensively involve secondary combustibles.
N
Table APLA-35/37.1 BFN Fire Area Evaluation E-8 Fire Area/Zone Location Description Realistic Fire Evaluation Extensive Secondary Combustible Involvement (Y/N) 01-06 U1 Reactor Bldg, EL 639 south of Col. R.
The significant ignition sources of the transformer and Variable Frequency Drive on the south portion of 639 elevation are separated from each other and spread over a large area. Area wide detection coverage and area wide automatic suppression coverage are provided over the south portion of 639 elevation. With the area wide detection coverage and area wide automatic suppression coverage over the significant ignition sources, there are no credible fire scenarios with the potential to extensively involve secondary combustibles.
N 02-01 U2 Reactor Bldg, EL 519 - 565, from Col.
R8 to 10 ft east of Col. R11.
The significant ignition source is the electrical board on the 565 elevation. Area wide detection coverage and area wide automatic suppression coverage are provided over the entire 565 elevation. The ignition sources on the 519 elevation are located in corner rooms and are separated from the each other by large distances over a large area. The pumps areas have detection, but no suppression. With the area wide detection coverage and area wide automatic suppression coverage over the electrical boards, there are no credible fire scenarios with the potential to extensively involve secondary combustibles.
N
Table APLA-35/37.1 BFN Fire Area Evaluation E-9 Fire Area/Zone Location Description Realistic Fire Evaluation Extensive Secondary Combustible Involvement (Y/N) 02-02 Unit 2 Reactor Bldg, EL 519 - 565, from Col.
R14 to 10 ft. west of Col. R11.
The ignition sources of the electrical boards on the 565 elevation are separated from the each other by large distances over a large area with a high ceiling. Area wide detection coverage and area wide automatic suppression coverage are provided over the entire 565 elevation. The ignition sources on the 519 elevation are located in corner rooms and are separated from each other by large distances over a large area and a wall separates the HPCI pump from other areas. This HPCI area is protected by detection and automatic suppression. The other pumps areas have detection, but no suppression. With the area wide detection coverage and area wide automatic suppression coverage over the electrical boards, there are no credible fire scenarios with the potential to extensively involve secondary combustibles.
N 02-03 U2 Reactor Bldg, EL 593, north of Col. R.
There are no significant ignition sources on the 593 elevation. Area wide detection coverage and area wide automatic suppression coverage is provided over the entire 593 elevation. The single pump area is protected by area wide detection and automatic suppression. These pumps do not present significant ignition source due to lack of combustible material present. With the area wide detection coverage and area wide suppression coverage over the 593 elevation, there are no credible fire scenarios with the potential to extensively involve secondary combustibles.
N
Table APLA-35/37.1 BFN Fire Area Evaluation E-10 Fire Area/Zone Location Description Realistic Fire Evaluation Extensive Secondary Combustible Involvement (Y/N) 02-04 U2 Reactor Bldg, EL 593 south of Col. Q and RHR Heat Exchanger
- Rooms, EL.565 and 593.
The significant ignition source is the electrical board on the 593 elevation. Area wide detection coverage and area wide automatic suppression coverage are provided over the entire 593 elevation. The pumps areas are protected by area wide detection and automatic suppression. These pumps do not present significant ignition sources due to lack of combustible material present. With the area wide detection coverage and area wide suppression coverage over the 593 elevation, there are no credible fire scenarios with the potential to extensively involve secondary combustibles.
N 02-05 U2 Reactor Bldg on EL 621 and EL 639 north of Col. R.
The significant ignition sources of the electrical boards, MG sets, transformers and pumps on the 621 elevation are separated from the each other and spread over a large area. Area wide detection coverage and area wide automatic suppression coverage are provided over the entire 621 elevation. The SLC pumps' area on the north 639 elevation has detection, but no suppression. These pumps do not present significant ignition sources due to lack of combustible material present. With the area wide detection coverage and area wide automatic suppression coverage over the significant ignition sources, there are no credible fire scenarios with the potential to extensively involve secondary combustibles.
N
Table APLA-35/37.1 BFN Fire Area Evaluation E-11 Fire Area/Zone Location Description Realistic Fire Evaluation Extensive Secondary Combustible Involvement (Y/N) 02-06 U2 Reactor Bldg, EL 639 south of Col. R.
The significant ignition sources of the electrical board, MG sets, transformers and Variable Frequency Drive on the 639 elevation are separated from the each other and spread over a large area. Area wide detection coverage and area wide automatic suppression coverage are provided over the south portion of the 639 elevation. With the area wide detection coverage and area wide automatic suppression coverage over the significant ignition sources, there are no credible fire scenarios with the potential to extensively involve secondary combustibles.
N 03-01 U3 Reactor Bldg, EL 519 - 565, from Col.
R15 to 10 ft east of Col. R18, equipment hatch between Cols. R15 to R16, T and U at EL 593 and 621 and on EL 639 south of Col. R.
The significant ignition source is the electrical board on the 565 elevation. Area wide detection coverage and area wide automatic suppression coverage are provided over the entire 565 elevation. The ignition sources on the 519 elevation are located in corner rooms and are separated from each other by large distances over a large area. The pumps areas have detection, but no suppression. The significant ignition sources of the transformer and Variable Frequency Drive on the 639 elevation are separated from the each other and spread over a large area. Area wide detection coverage and area wide automatic suppression coverage is provided over the south portion of the 639 elevation. With the area wide detection coverage and area wide automatic suppression coverage over the significant ignition sources, there are no credible fire scenarios with the potential to extensively involve secondary combustibles.
N
Table APLA-35/37.1 BFN Fire Area Evaluation E-12 Fire Area/Zone Location Description Realistic Fire Evaluation Extensive Secondary Combustible Involvement (Y/N) 03-02 U3 Reactor Bldg, EL 519 - 565, from Col.
R21 to 10 ft west of Col. R18.
The significant ignition sources of the electrical boards on the 565 elevation are separated from the each other by large distances over a large area with a high ceiling. Area wide detection coverage and area wide automatic suppression coverage are provided over the entire 565 elevation. The ignition sources on the 519 elevation are located in corner rooms, they are separated from each other by large distances over a large area, and a wall separates the HPCI pump from other areas. This HPCI area is protected by detection and automatic suppression. The other pumps areas have detection but no suppression. With the area wide detection coverage and area wide automatic suppression coverage over the electrical boards, there are no credible fire scenarios with the potential to extensively involve secondary combustibles.
N 03-03 U3 Reactor Bldg, EL 593, and RHR heat exchanger rooms, EL 565 and 593 near Col.
R15-S and R21-S.
The significant ignition source is the electrical board on the 593 elevation. Area wide detection coverage and area wide automatic suppression coverage are provided over the entire 593 elevation. The pumps areas are protected by area wide detection and automatic suppression. These pumps do not present significant ignition sources due to lack of combustible material present. With the area wide detection coverage and area wide suppression coverage over the 593 elevation, there are no credible fire scenarios with the potential to extensively involve secondary combustibles.
N
Table APLA-35/37.1 BFN Fire Area Evaluation E-13 Fire Area/Zone Location Description Realistic Fire Evaluation Extensive Secondary Combustible Involvement (Y/N) 03-04 U3 Reactor Bldg, EL 621 and EL 639 north of Col. R.
The significant ignition sources of the electrical boards, MG sets, transformers and pumps on the 621 elevation are separated from each other and spread over a large area. Area wide detection coverage and area wide automatic suppression coverage are provided over the entire 621 elevation. The SLC pumps area on the north 639 elevation has detection, but no suppression.
These pumps do not present significant ignition sources due to lack of combustible material present. With the area wide detection coverage and area wide automatic suppression coverage over the significant ignition sources, there are no credible fire scenarios with the potential to extensively involve secondary combustibles.
N 04 4kV Shutdown Board Room B, U1, Reactor Bldg EL 593 The ignition sources in the area are the electrical boards, and the boards/equipment in the area would be impacted due to the small room size. Since there is detection, but no automatic suppression, extinguishment of the fire would depend upon the fire brigade response that takes approximately 10 minutes. There are credible fire scenarios with the potential to extensively involve secondary combustibles.
Y
Table APLA-35/37.1 BFN Fire Area Evaluation E-14 Fire Area/Zone Location Description Realistic Fire Evaluation Extensive Secondary Combustible Involvement (Y/N) 05 4kV Shutdown Board Room A and 250V Battery Room, EL 621 U1 Reactor Bldg The ignition sources in the area are the electrical boards and the boards/equipment in the area would be impacted due to the small room size. Since there is detection, but no automatic suppression, extinguishment of the fire would depend upon the fire brigade response that takes approximately 10 minutes. There are credible fire scenarios with the potential to extensively involve secondary combustibles.
Y 06 480V Shutdown Board Room 1A, U1 Reactor Bldg - EL 621 The ignition source in the area is the electrical board and the board/equipment in the area would be impacted due to the small room size. Since there is detection, but no automatic suppression, extinguishment of the fire would depend upon the fire brigade response that takes approximately 10 minutes. There are credible fire scenarios with the potential to extensively involve secondary combustibles.
Y 07 480V Shutdown Board Room 1B, U1 Reactor Bldg - EL 621 The ignition source in the area is the electrical board and the board/equipment in the area would be impacted due to the small room size. Since there is detection, but no automatic suppression, extinguishment of the fire would depend upon the fire brigade response that takes approximately 10 minutes. There are credible fire scenarios with the potential to extensively involve secondary combustibles.
Y
Table APLA-35/37.1 BFN Fire Area Evaluation E-15 Fire Area/Zone Location Description Realistic Fire Evaluation Extensive Secondary Combustible Involvement (Y/N) 08 4kV Shutdown Board Room D, U2 Reactor Bldg - EL 593 The ignition sources in the area are the electrical boards and the boards/equipment in the area would be impacted due to the small room size. Since there is detection, but no automatic suppression, extinguishment of the fire would depend upon the fire brigade response that takes approximately 10 minutes. There are credible fire scenarios with the potential to extensively involve secondary combustibles.
Y 09 4kV Shutdown Board Room C and 250V Battery Room U2 Reactor Bldg - EL 621 The ignition sources in the area are the electrical boards and the boards/equipment in the area would be impacted due to the small room size. Since there is detection, but no automatic suppression, extinguishment of the fire would depend upon the fire brigade response that takes approximately 10 minutes. There are credible fire scenarios with the potential to extensively involve secondary combustibles.
Y 10 480V Shutdown Board Room 2A, U2 Reactor Bldg - EL 621 The ignition source in the area is the electrical board and the board/equipment in the area would be impacted due to the small room size. Since there is detection, but no automatic suppression, extinguishment of the fire would depend upon the fire brigade response that takes approximately 10 minutes. There are credible fire scenarios with the potential to extensively involve secondary combustibles.
Y
Table APLA-35/37.1 BFN Fire Area Evaluation E-16 Fire Area/Zone Location Description Realistic Fire Evaluation Extensive Secondary Combustible Involvement (Y/N) 11 480V Shutdown Board Room 2B, U2 Reactor Bldg - EL 621 The ignition source in the area is the electrical board and the board/equipment in the area would be impacted due to the small room size. Since there is detection, but no automatic suppression, extinguishment of the fire would depend upon the fire brigade response that takes approximately 10 minutes. There are credible fire scenarios with the potential to extensively involve secondary combustibles.
Y 12 480V RMOV Board Room 3B U3 Reactor Bldg - EL 593 The ignition sources in the area are the electrical boards and the boards/equipment in the area would be impacted due to the small room size. Since there is detection, but no automatic suppression, extinguishment of the fire would depend upon the fire brigade response that takes approximately 10 minutes. There are credible fire scenarios with the potential to extensively involve secondary combustibles.
Y 13 Shutdown Board Room 3A, U3 Reactor Bldg - EL 621 The ignition sources in the area are the electrical boards and the boards/equipment in the area would be impacted due to the small room size. Since there is detection, but no automatic suppression, extinguishment of the fire would depend upon the fire brigade response that takes approximately 10 minutes. There are credible fire scenarios with the potential to extensively involve secondary combustibles.
Y
Table APLA-35/37.1 BFN Fire Area Evaluation E-17 Fire Area/Zone Location Description Realistic Fire Evaluation Extensive Secondary Combustible Involvement (Y/N) 14 480V Shutdown Board 3A U3 Reactor Bldg - EL 621 The ignition source in the area is the electrical board and the board/equipment in the area would be impacted due to the small room size. Since there is detection, but no automatic suppression, extinguishment of the fire would depend upon the fire brigade response that takes approximately 10 minutes. There are credible fire scenarios with the potential to extensively involve secondary combustibles.
Y 15 480V Shutdown Board Room 3B U3 Reactor Bldg - EL 621 The ignition source in the area is the electrical board and the board/equipment in the area would be impacted due to the small room size. Since there is detection, but no automatic suppression, extinguishment of the fire would depend upon the fire brigade response that takes approximately 10 minutes. There are credible fire scenarios with the potential to extensively involve secondary combustibles.
Y 16 Control Bldg EL 593, 606, and 617 Cables in the cable spreading rooms and Control Rooms represent a sizable fire load. The cable spreading room is protected with a specifically designed automatic suppression system to control fires in areas of high concentration of electrical cables. The main Control Rooms are protected with area wide smoke detection, both above and below the false ceiling. Some electrical boards are provided with smoke detection. Since the Control Rooms are continuously manned and provided with detection, fast developing fires are not expected. The worst case fire would be in an electrical board which contains control circuits (250 VDC maximum) for site offsite power and U1/2 Emergency Diesel Generators (EDG)
Table APLA-35/37.1 BFN Fire Area Evaluation E-18 Fire Area/Zone Location Description Realistic Fire Evaluation Extensive Secondary Combustible Involvement (Y/N) controls. The thermal energy of a realistic electrical board fire is expected to be extremely low and not be capable of damaging a large number of components/circuits. However, even assuming all circuits in the panel are fire damaged (extremely conservative) the Unit 1 & 2 EDG can be restored from the backup control stations and the safe shutdown systems will function as designed. The Unit 3 EDG are not impacted by a fire at this panel.
Fires involving a main control board panel are expected to be restricted to an individual panel since the panels are separated from each other via steel partitions.
Therefore, only single divisions of mitigating systems will be affected.
For the other rooms in the Control Bay, the walls of rooms provide a credible fire barrier which limits the potential fire impact in the area. Area wide detection and suppression in the cable spreading rooms would retard fire development and limit the number of affected components.
- As discussed above, the likelihood of a control bay fire resulting in extensive collateral damage is small, however, because of the special significance of fires affecting control cabling, this area will be addressed in Table APLA-35/37.2 below.
Table APLA-35/37.1 BFN Fire Area Evaluation E-19 Fire Area/Zone Location Description Realistic Fire Evaluation Extensive Secondary Combustible Involvement (Y/N) 17 U1 Battery and Battery Board Room Control Bldg - EL 593 The ignition sources in the area are the battery, charger, inverter, motor-motor-generator (MMG) set, electrical boards and the battery, boards and equipment in the area would be impacted due to the small room size. Since there is detection with manual suppression, extinguishment of the fire would depend upon manual activation of the suppression system. This should be a rapid response due to the close proximity of the area to the Control Room. Thus, there are no credible fire scenarios with the potential to extensively involve secondary combustibles.
N 18 U2 Battery and Battery Board Room, Control Bldg - EL 593 The ignition sources in the area are the battery, charger, inverter, MMG set, electrical boards and the battery, boards and equipment in the area would be impacted due to the small room size. Since there is detection with manual suppression, extinguishment of the fire would depend upon manual activation of the suppression system. This should be a rapid response due to the close proximity of the area to the Control Room.
Thus, there are no credible fire scenarios with the potential to extensively involve secondary combustibles.
N
Table APLA-35/37.1 BFN Fire Area Evaluation E-20 Fire Area/Zone Location Description Realistic Fire Evaluation Extensive Secondary Combustible Involvement (Y/N) 19 U3 Battery and Battery Board Room, Control Bldg - EL 593 The ignition sources in the area are the battery, charger, inverter, MMG set, electrical boards and the battery, boards and equipment in the area would be impacted due to the small room size. Since there is detection with manual suppression, extinguishment of the fire would depend upon manual activation of the suppression system. This should be a rapid response due to the close proximity of the area to the Control Room.
Thus, there are no credible fire scenarios with the potential to extensively involve secondary combustibles.
N 20 Units 1 and 2 Diesel Generator Bldg, All Elevations The significant ignition sources are the four diesel generators, which are located in separate rooms, and the electrical boards in a separate room. The fuel oil transfer pump room represents a sizable fire load, which is located in a separate room. Detection coverage and automatic suppression coverage are provided over the loads and fire sources in the separate rooms. The walls of rooms provide a credible fire barrier which limits any potential fire impact in the area. With the detection coverage and suppression coverage in the diesel generator building, there are no credible fire scenarios with the potential to extensively involve secondary combustibles.
N
Table APLA-35/37.1 BFN Fire Area Evaluation E-21 Fire Area/Zone Location Description Realistic Fire Evaluation Extensive Secondary Combustible Involvement (Y/N) 21 Unit 3 Diesel Generator Bldg, All Elevations The significant ignition sources are the four diesel generators which are located in separate rooms and the electrical boards in a separate room. The fuel oil transfer pump room represents a sizable fire load which is located in a separate room. Detection coverage and automatic suppression coverage are provided over the loads and fire sources in the separate rooms. The walls of rooms provide a credible fire barrier which limits any potential fire impact in the area. With the detection coverage and suppression coverage in the diesel generator building, there are no credible fire scenarios with the potential to extensively involve secondary combustibles.
N 22 4kV Shutdown Board Room 3EA and
- 3EB, U3 Diesel Generator Bldg - EL 565.5 &
583.5 The ignition sources in the area are the electrical boards and the boards/equipment in the area would be impacted due to the small room size. Since there is detection, but no automatic suppression, extinguishment of the fire would depend upon the fire brigade response that takes approximately 10 minutes. There are credible fire scenarios with the potential to extensively involve secondary combustibles.
Y
Table APLA-35/37.1 BFN Fire Area Evaluation E-22 Fire Area/Zone Location Description Realistic Fire Evaluation Extensive Secondary Combustible Involvement (Y/N) 23 4kV Shutdown Board Room 3EC and
- 3ED, U3 Diesel Generator Bldg - EL 565.5 &
583.5 The ignition sources in the area are the electrical boards and the boards/equipment in the area would be impacted due to the small room size. Since there is detection, but no automatic suppression, extinguishment of the fire would depend upon the fire brigade response that takes approximately 10 minutes. There are credible fire scenarios with the potential to extensively involve secondary combustibles.
Y 24 4kV Bus Tie Board Room U3 Diesel Generator Bldg - EL 565 The ignition source in the area is the electrical board and the board/equipment in the area would be impacted due to the small room size. Since there is detection, but no automatic suppression, extinguishment of the fire would depend upon the fire brigade response that takes approximately 10 minutes. This board is de-energized in normal plant operating alignments, during which time the fire potential is small. Discounting consideration of the small periods of time that this board might be energized, there are credible fire scenarios with the potential to extensively involve secondary combustibles.
Y
Table APLA-35/37.1 BFN Fire Area Evaluation E-23 Fire Area/Zone Location Description Realistic Fire Evaluation Extensive Secondary Combustible Involvement (Y/N) 25 TB Turbine Bldg, Steam Tunnel and Radwaste Bldg The significant ignition sources are the turbines, generators, electrical boards and transformers which are located in separate areas of the 3 Units Turbine Building. The turbine fuel oil storage tanks represent sizable fire loads, but are protected by deluge sprinkler systems. The 3 units turbine building has only limited detection coverage and automatic suppression coverage. Since there is only limited detection and automatic suppression, extinguishment of the fire would depend upon the fire brigade response that takes approximately 10 minutes. Thus, there are credible fire scenarios which could result in extensive collateral damage to BOP systems. However, due to the large area and separation between the units, a fire would not likely involve multiple units.
Y
Table APLA-35/37.1 BFN Fire Area Evaluation E-24 Fire Area/Zone Location Description Realistic Fire Evaluation Extensive Secondary Combustible Involvement (Y/N) 25 IPS Cable Tunnel and Intake Pumping Station, In the Intake Pumping Station, the ignition sources of the transformers TW1, TW2 & TW3 and Buses 1, 2 & 3 are separated from the Condenser Circulating Water (CCW) and RHRSW pumps and cables by distance and a concrete wall with limited openings. There are no ignition sources in the portion of the intake pumping station containing the RHRSW and CCW cables. This area is protected by detection and automatic suppression. In addition, the cables for the RHRSW Pumps are separated into two divisions with one division wrapped in TSI Thermo-lag.
Thus, there are no credible fire scenarios with the potential to extensively involve secondary combustibles.
The CCW cables are located in 4 trays with a maximum of 4 CCW pumps potentially lost by a fire in any one tray.
A fire in these trays can damage one division of the RHRSW pumps and 4 CCW pumps and potentially result in a unit trip (due to loss of main condenser vacuum).
However, the redundant division of the RHRSW pumps remains available to provide decay heat removal capability as necessary.
N
Table APLA-35/37.2 BFN Fire Area Equipment Assessment E-25 Overview Making use of all equipment expected to be available in a fire situation (i.e., not limiting available equipment to only the set of response equipment utilized in the safe shutdown instructions), a plant response methodology was assessed for each of the area/zones where a fire having extensive secondary combustibles involvement is deemed to be physically realistic. In nine of the seventeen fire area/zones tabulated below, the fire will cause only partial Reactor Protection System (RPS)/Primary Containment Isolation System (PCIS) actuations, and manual shutdown using BOP equipment will occur.
In the remaining eight areas, U1, U2, and/or U3 can be expected to experience a scram/isolation transient as a direct result of the fire effects. The table entries for these eight fire areas are indicated via shading.
Fire Area/Zone Location/Description EOI-based Fire Response summary 04 4kV Shutdown Board Room B, U1, Reactor Bldg EL 593
- U1 - suppression pool cooling by one RHR pump/heat exchanger, reactor vessel inventory maintained by HPCI with reactor pressurized and by BOP equipment after reactor is depressurized. COP required (only if rapid depressurization occurs). No CIV circuits routed through this fire area
- U2 - high pressure injection available. Reactor cool down to main condenser can be established. No suppression pool cooling required
- U3 - remain in power operation largely unaffected
Table APLA-35/37.2 BFN Fire Area Equipment Assessment E-26 Fire Area/Zone Location/Description EOI-based Fire Response summary 05 4kV Shutdown Board Room A and 250V Battery Room, EL 621 U1 Reactor Bldg.
- U1 - suppression pool cooling by two RHR pumps/heat exchangers, reactor vessel inventory maintained by BOP equipment after reactor depressurization. COP not required.
- U2 - high pressure injection available. Reactor cool down to main condenser can be established. No suppression pool cooling required.
- U3 - remain in power operation largely unaffected 06 480V Shutdown Board Room 1A, U1 Reactor Bldg - EL 621
- U1 - half-scram and PCIS groups 2, 3, 6, and 8 actuation due to loss of RPS bus 1A. Controlled manual shutdown.
- U2 - remain in power operation largely unaffected
- U3 - remain in power operation largely unaffected 07 480V Shutdown Board Room 1B, U1 Reactor Bldg - EL 621
- U1 - half-scram and PCIS groups 2, 3, 6, and 8 actuation due to loss of RPS bus 1B. Controlled manual shutdown.
- U2 - remain in power operation largely unaffected
- U3 - remain in power operation largely unaffected 08 4kV Shutdown Board Room D, U2 Reactor Bldg - EL 593
- U1 - high pressure injection available. Reactor cool down to main condenser can be established. No suppression pool cooling required
- U2 - suppression pool cooling by two RHR pumps/heat exchangers, reactor vessel inventory maintained by HPCI with reactor pressurized and by BOP equipment after reactor is depressurized. COP not required
- U3 - remain in power operation largely unaffected
Table APLA-35/37.2 BFN Fire Area Equipment Assessment E-27 Fire Area/Zone Location/Description EOI-based Fire Response summary 09 4kV Shutdown Board Room C and 250V Battery Room, U2 Reactor Bldg - EL 621
- U1 - high pressure injection available. Reactor cool down to main condenser can be established. No suppression pool cooling required.
- U2 - suppression pool cooling by one RHR pump/heat exchanger, reactor vessel inventory maintained by BOP equipment after reactor depressurization. COP required. No CIV circuits routed through this fire area.
- U3 - remain in power operation largely unaffected 10 480V Shutdown Board Room 2A, U2 Reactor Bldg - EL 621
- U1 - remain in power operation largely unaffected
- U2 - half-scram and PCIS groups 2, 3, 6, and 8 actuation due to loss of RPS bus 2A. Controlled manual shutdown.
- U3 - remain in power operation largely unaffected 11 480V Shutdown Board Room 2B, U2 Reactor Bldg - EL 621
- U1 - remain in power operation largely unaffected
- U2 - half-scram and PCIS groups 2, 3, 6, and 8 actuation due to loss of RPS bus 2B. Controlled manual shutdown.
- U3 - remain in power operation largely unaffected 12 480V RMOV Board Room 3B, U3 Reactor Bldg
- EL 593
- U1 - remain in power operation largely unaffected
- U2 - remain in power operation largely unaffected
- U3 - half-scram and PCIS groups 2, 3, 6, and 8 actuation due to loss of RPS bus 3B. Controlled manual shutdown.
Table APLA-35/37.2 BFN Fire Area Equipment Assessment E-28 Fire Area/Zone Location/Description EOI-based Fire Response summary 13 Shutdown Board Room 3A, U3 Reactor Bldg - EL 621
- U1 - remain in power operation largely unaffected
- U2 - remain in power operation largely unaffected
- U3 - suppression pool cooling by two RHR pumps/heat exchangers, reactor vessel inventory maintained by BOP equipment after reactor depressurization. COP not required.
14 480V Shutdown Board 3A U3 Reactor Bldg -
EL 621
- U1 - remain in power operation largely unaffected
- U2 - remain in power operation largely unaffected
- U3 - half-scram and PCIS groups 2, 3, 6, and 8 actuation due to loss of RPS bus 3A. Controlled manual shutdown.
15 480V Shutdown Board Room 3B U3 Reactor Bldg - EL 621
- U1 - remain in power operation largely unaffected
- U2 - remain in power operation largely unaffected
- U3 - half-scram and PCIS groups 2, 3, 6, and 8 actuation due to loss of RPS bus 3B. Controlled manual shutdown.
Table APLA-35/37.2 BFN Fire Area Equipment Assessment E-29 Fire Area/Zone Location/Description EOI-based Fire Response summary 16 Control Bldg EL 593, 606, and 617 As discussed in Table APLA-35/37.1 above, a fire in this area would not be expected to progress such that extensive secondary combustible involvement occurs.
However, BFN is designed for shutdown from outside the main control rooms. In the worst case, a fire could force control room abandonment and a loss of all off-site power. A three unit LOOP is also considered as part of the BFN design basis. Each unit would retain high pressure injection and low pressure injection sources to provide core cooling, and each unit would have two RHR pumps available for suppression pool cooling
- U1 - high pressure/low pressure injection available, suppression pool cooling by two RHR pumps/heat exchangers. No COP required.
- U2 - high pressure/low pressure injection available, suppression pool cooling by two RHR pumps/heat exchangers. No COP required.
- U3 - high pressure/low pressure injection available, suppression pool cooling by two RHR pumps/heat exchangers. No COP required.
Table APLA-35/37.2 BFN Fire Area Equipment Assessment E-30 Fire Area/Zone Location/Description EOI-based Fire Response summary 22 4kV Shutdown Board Room 3EA and 3EB, U3 Diesel Generator Bldg - EL 565.5 &
583.5
- U1 - high pressure injection available. Reactor cool down to main condenser can be established. No suppression pool cooling required
- U2 - high pressure injection available. Reactor cool down to main condenser can be established. No suppression pool cooling required
- U3 - half-scram and PCIS groups 2, 3, 6, and 8 actuation due to loss of RPS bus 3A. Controlled manual shutdown.
23 4kV Shutdown Board Room 3EC and 3ED, U3 Diesel Generator Bldg - EL 565.5 &
583.5
- U1 - remain in power operation largely unaffected
- U2 - remain in power operation largely unaffected
- U3 - half-scram and PCIS groups 2, 3, 6, and 8 actuation due to loss of RPS bus 3B. Controlled manual shutdown.
24 4kV Bus Tie Board Room U3 Diesel Generator Bldg - EL 565
- U1 - high pressure injection available. Reactor cool down to main condenser can be established. No suppression pool cooling required.
- U2 - high pressure injection available. Reactor cool down to main condenser can be established. No suppression pool cooling required.
- U3 - remain in power operation largely unaffected
Table APLA-35/37.2 BFN Fire Area Equipment Assessment E-31 Fire Area/Zone Location/Description EOI-based Fire Response summary 25 TB Turbine Building, Steam Tunnel and Radwaste Bldg A fire in these areas would not be expected to affect more than one unit, however, in the worst case, the fire could result in a loss of offsite power to all three units. A three unit LOOP is part of the BFN design basis. Each unit would retain high pressure injection and low pressure injection sources to provide core cooling, and each unit would have two RHR pumps available for suppression pool cooling.
- U1 - high pressure/low pressure injection available, suppression pool cooling by two RHR pumps/heat exchangers. No COP required.