ML20081D232
| ML20081D232 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 10/27/1983 |
| From: | Stewart W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| To: | Harold Denton, John Miller Office of Nuclear Reactor Regulation |
| References | |
| 605, NUDOCS 8311010075 | |
| Download: ML20081D232 (5) | |
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VINGINIA ELECTRIC AND POWEN COMPANY RIcitxoNo,VINGINIA 202 61 W.L.SrswAmr vics r==.no=wr October 27, 1983 A
Neu. man orsmArrows 1
l Mr. Harold R. Denton, Director Serial No. 605 Office of Nuclear Reactor Regulation N0/JHL:acm i
Attn:
Mr. James R. Miller, Chief Docket Nos. 50-338 Operating Reactors Branch No. 3 50-339 Division of Licensing License Nos. NPF-4 1
i U. S. Nuclear Regulatory Commission NPF-7 Washington, D. C. 20555 Gentlemen:
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VIRGINIA ELECTRIC AND POWER COMPAhT i
NORTH ANNA POWER STATICN UNIT NOS. 1 AND 2 SYSTEM DESCRIPTION OF THE EMERGENCY SWITCHGEAR ROOM HALON SYSTEM i
l Enclosed is the design description of the modifications that are necessary for i
the emergency switchgear rooms at North Anna Unit Nos. I and'2.
The modifica-tions are to install a Halon 1301 fire suppression system in each units emergency switchgear room.
These modifications are necessary to comply with Item III.G.3 of Appendix R and this submittal is necessary to comply with 10 j
CFR 50.48(c)(5).
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Very truly yours,
(
~f W. L. Stewart Enclosure l
cc:
Mr. James P. O'Reilly i
Regional Administrator Region II i
Mr. M. B. Shymlock NRC Resident Inspector North Anna Power Station l
Rock B311010075 831027 PDR ADOCK 05000338 ma F
PDR f
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SYSTEM DESCRIPTION l
EMERGENCY SWITCHGEAR ROOM HALON 1301 FIRE SUPPRESSION SYSTEM NORTH ANNA POWER STATION UNITS 1 AND 2 1.0 GENERAL INFORMATION 1.1 The Emergency Switchgear Room (ESR) at North Anna Power Station houses vital emergency power buses, cabling, relay racks, various equipment protection racks, air conditioning equipment, switchgear and the auxiliary shutdown panel.
The ESR is located in the basement of the service building belcw the Control Room. Unit 1 and Unit 2 each have their own Switchgear Rooms that are similar in both content and floorplans. A three hour fire wall and a three hour hinged double fire door separates the Unit 1 ESR from the Unit 2 ESR. The ESR's are separated from the rest of the plant by three hour walls, doors and ceilings.
Battery Rooms inside the ESR are separated by three hour doors, walls and dampers.
1.2 The Emergency Switchgear Rooms at both North Anna and Surry are presently protected by smoke detectors, fire extingu'ishers and standpipe hose racks located directly outside the ESR. Vepco filed for exemption for Surry Power Station, from 10CFR S0.48, Appendix R,Section III.G.3, that required a fixed fire suppression system.
The exemption request was based on Vepco's definition of standpipes and hose racks as fixed fire suppression and the fact that a suppression system would not enhance fire protection in the ESR.
In a letter l
from the NRC for Surry Power Station dated 1/19/83 serial #043, the exemption request was denied. Therefore, because the North Anna basis for exemption is the same, a fixed fire suppression system needs to be installed at North Anna to meet the requirements of Appendix R, III.G.3.
2.0 DESIGN DESCRIPTION 2.1 The entire system design shall be in accordance with the requirements of NFPA 12A.
2.2 The Halon 1301 system for both Unit 1 and Unit 2 Emergency Switchgear Rooms shall be a total flooding system with each units Emergency Switchgear Room to be considered a separate hazard area.
2.3 The system shall be operated manually by electric pushbuttons located in the stairwell between the control room and the Switchgear Rooms and another located at the main entrance to each units Switchgear Room.
In the event that the pushbuttons are inoperative,'the Halon shall be capable of being discharged by a device at the storage bottles and damper closure shall be accomplished by a manual switch at the control panel.
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2.4 Annunciation of system operation shall be both local and remote in the control room.
Local annunciation shall be by strobe lights located at all exits (outside protected area) with audible alarm located in each protected area (Units 1 & 2).
Remote annunciation shall be accomplished through the Robertshaw system presently being used by the station. The Robertshaw system shall also annunciate trouble alarms.
2.5 The system shall be a total flooding Halon system where the storage bottles are located outside the hazard area.
Each unit shall have its own main supply of Halon while one reserve set of Halon bottles (sized for the largest hazard area) will be stored at the station.
2.6 Each set of Halon storage bottles shall have at least two actuators (pilot valves) to provide maximum reliability, so that all bottles discharge in the event of a fire.
2.7 The initial discharge shall be completed within 10 seconds or less and shall reach a concentration throughout the protected area of 6 percent. The system shall be capable of l'olding concentrations for 10 minutes of no less than 5 percent and not more than 10 percent.
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2.8 Both the make up air and exhaust air system to the room affected shall be shut down so as not to dilute the concentration of Halon in the room; however, the recirculating HVAC system shall remain running so as to provide for mixing of Halon after discharge.
3.0 SYSTEM OPERATION 3.1 Operation of a manual discharge switch shall cause immediate I
activation of horns and lights and shut down devices (such as fire dampers) and activation of a predischarge timer which after 10 seconds shall discharge Halon into the room.
3.2 In the event of loss of normal power, the control panel shall provide battery backup to operate the panel under maximum normal load for 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> and then be capable of operating the system for five minutes continuously during an alarm condition.
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