TXX-6894, Forwards Addl Fire Protection Deviation to 10CFR50,App R, Section III.G.2 Re Failure of Redundant Solenoid Valves to Close Msivs.Deviation in Conjunction w/871002 Reported Deviation Provides Complete App R Update,Per 871021 Request
| ML20236C484 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 10/22/1987 |
| From: | Counsil W TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC) |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| TXX-6894, NUDOCS 8710270216 | |
| Download: ML20236C484 (4) | |
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1UELECTRIC I.
William G. Coumil h
Decutive ike hesident l
October 22, 1987 3
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U. S. Nuclear Regulatory Commission hh Z
l Attn Document Control Desk g
Washington, D. C. 20555
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SUBJECT:
COMANCHE PEAK STEAM ELECTRIC STATION (CPSES) b DOCKET NOS. 50-445 AND 50-446 FIRE PROTECTION DEVIATION
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REFERENCE:
- 2) NRC 1etter dated October 21, 1981 from H. R. Denton
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to R. J. Gary F
Gentlemen, Attached please find an additional deviation to 10CFR50 Appendix j
R Section III.C.2 concerning solenoid valves for tha Main Steam Isolation Valves (MS1V's).
This deviation in conjuction with previously transmitted deviations to 10CFR50 Appendix R (Reference j
- 1) provides a complete update of deviations for the Appendix R l
comparison requested by the NRC in Reference 2.
Very truly yours,.
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W. C. Counsil WCC a1 Attachment c - Mr. R. D. Martin, Region IV Resident Inspectors, CPSES (3) 6710270216 871022 PDR ADOCK 05000445 F
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0Yk 400 North Othe 5treet 1 11.81 Dallas,lexas 75201
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- llAtcachmentjtofTXX-6894
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Safezuards' 1
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- Building l 3-Elevation 873-6" Room 108 Fire 1 Area-SK17b Col.,N S:
!E W Reference. Drawings: -FHA-5 j
'Dev'iation:
' Appendix R to'.10CFR50 Section III.G.2.b H
Description:
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1 The main steam iso 1'ation valves 1-HV2333A, 1-HV2334A, 1HV3446A, and 1-HV2336A are located in separate compartments on the 873' 6* elevation-in Fire Zone'17B 1
-which extends up to the'880'-6"' elevation.in Fire Zone 170'in the Safeguards Building, _ On thel880'-6" elevation, a common walkway provides access into all
'four cubicles. The' cubicles are separated by:part-width concrete barriers which-extend out:to the open walkway,.The MSIV's..are separated by a minimum horizontal' distance 15 ft. via the open walkway around the partial barriers.
The MSIV's are equipped with stored energy actuators,' held open by hydraulic-pressure, and fail: closed on loss of hydraulic fluid ' Hydraulic' pressure is released to close the' valves by energizing-any.one of.two redundant solenoid valves: associated with each MSIV.
The redundant solenoid valves for each MSIV are-located withia each MSIV's-1
-compartment.
The'. solenoid valves within.each compartment are separated by a j
distance of approximately 18",
In the event of loss of.offsite power, all four i
.MSIV'.sLmust be operable; as such, at lease one'of the two redundant solenoid valves for each MSIV must be operable with offsite power available. (Tech Spec and FSAR p h nt operational. limits apply),' A fire in this area does not generate
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a requNnent for these valves to be closed,' except for the simultaneous condition of'a coincidental loss of offsite power, a
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Attachment to TXX-6894 Octobor 22, 1987 Page 2 of 3 Deviation 8e Justification:
1 1.
The MSIV's, all of which must be operable upon loss of offsite power, are separated by a minimum of 15 ft.
However, the actual fire propagation path is greater than 20 ft.
The fixed combustible loading is made up of the hydraulic fluid for the MSIV's which yields a one minute fire in the area.
All cable in the area is routed in conduit.
2.
Area wide automatic detection and suppression systems are provided in the area of the MSIV's and solenoid operated valves.
Transient combustibles are controlled by designating the area as no storage.
This assures that during maintenance, transient combustibles will not be left unattended.
3.
Raceways supplying power consist of 4" conduit with individual conduits branching off and supplying the valves (see attached sketch).
The solenoids which are located less than 2 ft. apart and the flexible conduits leading up to the solenoids are qualified to withstand conditions more extreme than conditions existing during a postulated one minute ASTM E-119 fire.
4.
The only combustible in the area is FYRQUEL Hydraulic Fluid. The fluid is contained inside a substantia 1' steel reservoir and steel piping. The probability of FYRQUEL leaking from the system is extremely low and physical damage to.the system is very unlikely. The reservoir is at atmospheric pressure.
Leakage of fluid from the reservoir should not atomize which further limits the potential for fire in this situation.
5.
The actuator manifolds and inner cylinder are high pressure systems.
Should fire result due to atomi.zation as a result of leakage under pressure, it would not impact on the ability of the valve to close.
Leakage of the-high pressure fluid will fail the valve closed, which is the desired position upon loss of offsite power.
In addition, a pressure switch installed in the high pressure system should provide indication of low system pressure in the Control Room.
This capability would provide early warning in the event of high pressure system leakage.
6.
The reservoir is at atmospheric pressure.
Leakage of fluid would not atomize, limiting the potential for fire in this situation.
In addition, a level switch is installed in the reservoir.
This level switch should provide early warning in the event of loss of hydraulic fluid from the reservoir.
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Attachment to TXX-6894 October 22, 1987 1
Page 3 of 3
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