ML20064F249
| ML20064F249 | |
| Person / Time | |
|---|---|
| Site: | 05200001 |
| Issue date: | 03/08/1994 |
| From: | Beard A GENERAL ELECTRIC CO. |
| To: | Poslusny C NRC |
| References | |
| NUDOCS 9403150235 | |
| Download: ML20064F249 (5) | |
Text
(1AR G '91 13:39 FP011 GE PCI' TO 5042260 PAGE.001/005
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GE NUCLEAR ENERGY REGULATORY OPERATIONS 12300 TWINBROOK PARKWAY SUITE 315 ROCKVILLE MD 20852 TELECOPY #:
301/770-5991 (8*571-5221)
VERIFICATION #.
301/770-5555 (8'57l 5200)
MT DATE:
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WR 8 '94 13:39 FPOf1 GE Pm TO 504226,0 Pf(E.802/005
.< n 21A6100 Rev. 3 ABWR staasnt sdory Auhsin sapoet shlied with floor drains to route leakage to the buement floor so that control or computer equipment is not subj(cted to water.
l Maximtun flooding may occur from leakage in a 700A service water line at a maximum rate of 12.0 m / min. Alarms (two<>ut-of-four logic) have been installed inside the 3
RCW/RSW i, t exchanger room to warn operators of a flood, ne first alarm is 400 mm above the basemat. It will wam the operators of flooding in a division. In the case of a RSW piping failure, a second set of alarms (twoout-offour k>gic) are located 1500 mm above basemat.This alarm will only sound in the event of a RSW piping failure inside the conuni building. The icvel sensors are powered from their respective divisional Class IE power supply. These sensors send signals to the concsponding divisions of the RSW sptems indicating flooding in that division of the C/B.This signal automatically closes isolation vahei, stops the pumps, and alarms the operators in the MCR. The expected release of a service water leak is liruited to line volume plus 1500 mm depth of water in a dhision. Water will be contained inside a division at the bottom level of the control building. A m2ximum of 5.0m of water is expected assuming 2 km of service water piping out to UHS ptunp house. Watertight doors will confine the water
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to a single division.
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4'e The fallure of a cooling water line in the mechanical rooms of the Control Building may lCg result in a leak of 0.6 m / min. Early detection by control room penonnel willlimit the 3
extent of flooding. Total release from the chilled water syste2n will be limited to line 1
8 inventory and surge tank volume, spillage of more than 6 m is unlikely. Elevation differences and separation of the mechanical ftmetions from the remainder of the Control Building prevent propagation of the water to the control area.
Flooding events that may result from the failure of the fire fighting systems within the control building are directed to the basement by the floor drain system On all floon, except the basement, water nnsitive equipment, outside the control room, will be raised atleast 200 rum oft the floor to protect thern in case of water jntrudon due to manual firefighting or other flooding event on their floor On the knat the water sensitive components of the RCW pumps will be kept at least 400 m t$f/ he floor for their protection]In the control room th 3jud mmouter floor]
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(Trevents in.rusion of water from areu outside the MCil fhere are no sprinkler systems 4' '
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in the Control Building. IIose and standpipes are located in the corridors. Service equipment rooms may build up limited water levels from either service water, cooling Y
water, or chilled water leaks, but elevation difTerences prevent intntsion of water into contml areas. Control room responses to those various levels of flooding may extend from sptem imlation and correction to reduction of plant load or shutdown, but control room capability is not compromised by any of the postulated flooding events.
nr water iennnoom onign - Amer 4 ment 23
11AR 8 '9J' 13:39 FFO1 GE PCK TD 5042260 PAGE.003/005 March 7,1994 Insert AA to Section 3.4.1.1.2.2 3
Manual fire fighting in the Control Building with 2 hand held hoses at 0.57 m /m each 3
(1.14 m /m total) ultimately results in the accumulation of water in the basement. The accumulation of water fiom I bour of fire suppression will not affect water sensitive safety-related equipment in the basement which are located at least 4(X) mm atx)ve the floor. Even in the unlikely event that fire suppression activities exterxi beyond I hour there is a substantial period of tine, before safety-related equipment may be effected.
Furthermore, the Division "A" RSW/RCW heat exchanger room in the basement is separated by water tight bauiers from the fire water accumulation in the other two divisions and would remain free of water damage and enable the reactor to be shutdown
- safely,
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lTR 8 'G4 13:39 FPO!1 f;E PCK 10 % 12260 F% E.00@ 005 e
23A6100 flev, 3 ABWR standard satory Analysis Report to burn out on its own without spicading to other areas. Ahesnatively,if the fire brigade is required to fight the fire manually the elevated entries inu> the room can accommodate approximately 30 minutes of additional water / foam 3
application from 2 hand held lines (OA7m / min per hose) before reaching the lowest door opening. The lowest door opening to these roorns are the cuerior equipment doors which could be opened if fire fighting activities necessitate so that any excess wa ter, foam, or diesel fuel would spill outside the building and not spicad to other parts of the reactor buildin (2) The Control Room Complex has a raised floor with a subfloor area which is
/"M g used for iooting of cables hom the Con 001 Room cabinets, panels, and the dhisional electrical rooms. Divisional separation of the subfloor cablingis maintained per the requirements of IEEE 3M.The subfloor area will include fire detection capability. The sub!!oor area will not contain a fire suppression systern as recommended by the BTP (IrfP CMEll 951, Section 7b),
Jmtification: Fire Haurd Analysis section 9A.4.2.4.1, itern 12 describes why the subfloor area is considered to be low risk fire area. In addition, the eff ectiveness of a permanently installed fire suppression sptem in the subfloor t
area is limited due to the small vertical space and the physical separation bmween the subfloor and the Control Room. Since the Control Room is continuously manned, manual fire suppression activides can be started qmckly once it has been determined that there is a fue in the subfloor area.
There are no tunsient combustibles stored in this area during normal activities to increase the sever;ty of a possible fire. The characteristics of the subfloor cables are such that the probability of a fire ignition are very low and any fire that weie to occur would be self. extinguishing or very slow to spread.
Since fire resistant cables are acquired the amount of water needed to extinguish fire in the subfloor is relatively small. Any water that is introduced h):o th_e_sul floor area can be remmp'T3m.w.pimmp3In the event y
that a fire in the Control Room were to 1equire evacuation, the Division I and 11 Remote Shutdown Panels enable the operators to bring the plant to a safe shutdown.
(3) The of fice spaces contained in the Control Room Cornplex do not have
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automatic fue suppression systems installed. IrFP CMEB 951, Section 7b
/d recommends that these spaces have automatic suppression.
Justification:The (%ntrol Room Cornplex is continumisly manned so that any g rI fire will be quir.kly detected and manual suppression will be commenced' "fg without delay.The amount of combustibles is limited. Papers within the g
Compicx are stored in file cabinets, book cases, or other storage locations t
except when in use.
l 952 M&
Other Auxiliary Sptems - Amendment 33
r-yg a ' 8 94 13:40 FFtTI GE RCK TO 5042260 P6YE.005/005 l
March 7,1994 changes insen AA to Section 9.5.1 (2)
Should mafmal fire fighting in the Control Room complex be necessary, the accumulation and/or drainage of fire water will not afTect the abiliy to safely shutdown the reactor.
t 3
Using 2 hand held hoses at 0.57 m /m cach (1.14 m>/m total) the subfloor area in the Contful Room will acconunodate a minimurn of I hour accumulation of water with no drainage without affecdng safety-related equipment. If tJx fire water is assumed to transport immediately to the basenwnt of the control building, the resulting accumulation of water will not affect safety-triated equipment located in de basement. In either case the fire fighting activities will not pruvent the teactor ff om tving safely shutdown.
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