ML20012D663

Responds to Generic Ltr 89-19 Re Resolution of USI A-47 on Safety Implications of Control Sys in Lwrs.Overfill Protection Sys Sufficiently Separate from Control Portion of Main Feedwater Control Sys & Not Powered from Same Source

ML20012D663
Person / Time
Site:	Vogtle
Issue date:	03/15/1990
From:	Hairston W GEORGIA POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
REF-GTECI-A-47, REF-GTECI-SY, TASK-A-47, TASK-OR ELV-01375, ELV-1375, GL-89-19, NUDOCS 9003280208
Download: ML20012D663 (3)

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tre uut% nnn e ctc Wn W,G Hairston m ICNNUI' March 15, 1990 ELV-01375 0260 Docket Nos. 50-424-

1. 50-425-U. S. Nuclear. Regulatory Commission ATTN: Document Control Desk

-Washington, D. C. 20555

~ Gentlemen:

V0GTLE ELECTRIC GENERATING PLANT RESPONSE TO GENERIC LETTER 89-19 In " Request For Action Related to Resolution of Unresolved Safety Issue A-47, Safety implications of Control Systems in LWR Nuclear Power Plants - Generic Letter 89-19", the staff concluded that all PWR plants should provide automatic steam generator overfill protection and that plant procedures and technical s >ecifications for all plants should include provisions to periodically verify tie operability of the overfill protection in order to assure that automatic overfill protection is available to mitigate main feedwater overfeed events

'during reactor power operation. Enclosure 2 of the Generic Letter outlined

.dtsigns that satisfied the objectives for overfill protection and provided

! guidance for an acceptable design for various classes of plants. Item 2 of Enclosure 2 discussed Westinghouse designed PWR plants and stated that alants that have:an overfill protection system initiated on a steam generator ligh-high Ewater level signal (based on a 2-out-of-4 initiating logic), which is safety

' grade, are acceptable provided that:

(1) the overfill protection system is sufficiently separate from the control portion of the MFW control system so that it is not powered from the same power source, not located in the same cabinet, and not routed so that a fire is likely to affect both systems, and (2) the plant procedures and technical specifications include requirements to periodically verify operability of this system.

The design of the feedwater isolation system has been reviewed for the VEGP-Units 1 and 2. A steam generator high-high water level signal generates a turbine trip signal, a trip of the feedwater pumps, and the closure of all feedwater isolation valves.

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The feedwater isolation valves consist of the main feedwater isolation valves l (MFIV's), bypass feedwater isolation valves (BFIV's), main feedwater regulating )

valves (MFRV's) and bypass feedwater regulating valves (BFRV's). The above valves receive Train A and Train B feedwater isolation signals. Each MFIV is powered by two separate pneumatic / hydraulic power trains with electric solenoids energized from separate Class IE sources. The BFIV's have air-operated piston i actuators provided to close the valves with electric solenoids energized from i separate Class IE sources. The MFRV's and BFRV's are air-operated with i electric solenoids energized from separate Class IE sources. All valves are j designed to fail closed. This design provides excellent assurance that, upon  !

receipt of a feedwater isolation signal, all flow to the steam generators will i be stopped as a result of the closure of these valves. Additionally, the j engineered safety features actuation system is train separated and routed so  !

that a fire is not likely to affect both systems.

The plant procedures and technical specifications have been reviewed to ensure )

that appropriate requirements exist to periodically verify operability of this  ;

system. This review has concluded that the turbine trip and feedwater isolation  :

signals have appropriate channel checks, channel calibrations and analog channel i operational testing. Additionally, the actuation logic test, master relay test, i and slave relay test are performed to ensure equipment actuation. Response time i testing and valve stroke testing is also performed to ensure that components  ?

function within the assumed time intervals. l Based upon the above review, Georgia Power Company has concluded that the VEGP  !

steam generator overfill protection system satisfies the recommendations of l Enclosure 2 to Generic Letter 89-19 for a Westinghouse Group I plant. Georgia l Power Company plans no other action in response to Generic Letter 89-19.

l Mr. W. G. Hairston, III states that he is a Senior Vice President of Georgia Power Company and is authorized to execute this oath on behalf of Georgia Power and that, to the best of his knowledge and belief, the facts set forth in this letter are true.

GEORGIA POWER COMPANY By: td d.l W n W. G. Hairston, 111 Sworn to and subscribed before me this /6 day of , 1990. i b

NotaryQ Public ,

W COMMISSION EXPIRES JANU ARY 12,1993 xc (see next page) i I'

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( Georgialknver1 U. S. Nuclear Regulatory Commission ELV-01375 Pace Three t- xc: Georoia Power Comp 1DX

Mr. C. K. McCoy L- Mr. G. Bockhold, Jr.

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~Mr. R. M. Odom Mr. P. D. Rushton NORMS U. S. Nuclear Reaulatory Commission

' Mr. S. D. Ebneter, Regional Administrator

'Mr. T. A. Reed, Licensing Project Manager, NRR Mr. R. F. Aiello, Senior Resident Inspector, Vogtle f :-

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