ML20043B541

Application for Amends to Licenses NPF-68 & NPF-81,revising Tech Spec Surveillance Requirement 4.8.1.1.2h(6)(c) Re High Jacket Water Temp Trip

ML20043B541
Person / Time
Site:	Vogtle
Issue date:	05/25/1990
From:	Hairston W GEORGIA POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20043B542	List: ML20043B541 ML20043B543
References
ELV-01713, ELV-1713, NUDOCS 9005300172
Download: ML20043B541 (6)

Text

e . Goorgia Powt Company

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• 333 Patnora Aetwe i

. Ateta Georga30308

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[ IAvhng /ddes 40 Irwerhett Conter Pahay pow OMce Box 1295 l II* W1 May 25, 1990 reuortew oe,*"

W. G. Ha6r6 ton, til Le'nor Vee P#et.ident Near operarons ELV-01713 0402 Docket Nos. 50-424 50-425 U. S. Nuclear Regulatory Commission 4 ATTN: Document Control Desk  !

Washington, D. C. 20555

. t Gentlemen: -

V0GTLE ELECTRIC GENERATING PLANT REQUEST TO REVISE TECHNICAL SPECIFICATJON 4.8.1.1.2h(6)(c) ,

In accordance with the provisions of 10 CFR 50.90 and 10 CFR 50.59, Georgia Power Company (GPC) hereby pro)oses to amend the Vogtle Electric Generating +

Plant (VEGP) Units 1 and 2 Tecinical Specifications, Appendix A to Operating Licenses NPF-68 and NPF-81. t Technical Specification (TS) Surveillance Requirement 4.8.1.1.2h(6)(c) requires verification that all automatic diesel generator trips, except engine overspeed, i low lube oil pressure, high jacket water temperature and generator differential are automatically bypassed upon loss of voltage on the emergency bus concurrent I

with a Safety Injection Actuation Signal. The proposed amendment would allow the high jacket water temperature trip to be bypassed to minimize the potential  !

for spurious diesel generator trips in the emergency start mode.

The proposed change and its basis are described in Enclosure 1. Our evaluation l

pursuant to to 10 CFR 50.92 showing that the proposed change does not involve t I significant hazards considerations is provided as Enclosure 2. Instructions for L incorporation of the proposed change into the Technical Specifications and a mark-up of the affected page is provided ?s Enclosure 3.

GPC requests that this proposed amendment .:e processed as an emergency Technical '

Specification change. The modification which allows the jacket water high .

temperature trip to be bypassed has become necessary to alleviate a continuing i problem of spurious trips caused by the jacket water temperature switches. GPC  :

believes that this modification needs to be made as soon as possible to increase diesel generator reliability.

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+005300172 900525 I ;

PDR ADOCK 05000424 FI P PDC ,

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U. S. Nuclear Regulatory Commission i ELV-01713 Paae Two In accordance with 10 CFR 50.91, the designated state official will be sent a copy of this letter and all enclosures.

Mr. W. G. Hairston, 111 states that he is a Senior Vice President of Georgia .,

Power Company and is authorized to execute this oath on behalf of Georgia Power 1 Company and that, to the best of his knowledge and belief, the facts set forth 1 in this letter and enclosures are true.

GEORGIA POWER COMPANY By: Itl. /b d W. G. Hairston, 111 Sworn to and subscribed before me thise5 day of % , 1990.

U b NRAtib Notary Public L WGH,III/NJS/gm (geonstwas>ELW

Enclosures:

1. Basis for Proposed Change

2. 10 CFR 50.92 Evaluation

3. Instructions for Incorporation and Revised Pages l c(w): Georoia Power Company l

Mr. C. K. McCoy

! Mr. G. Bockhold, Jr.

Mr. R. M. Odom

! Mr. P. D. Rushton l NORMS Southern Company Services L Mr. L. B. Long LL, 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 State of Georoia Mr. J. L. Ledbetter, Commissioner, Department of Natural Resources 4

l ENCLOSURE 1 V0GTLE ELECTRIC GENERATING PLANT RE0 VEST TO REVISE TECHNICAL SPECIFICATION 4.8.1.1.2h(6)(c) r BASIS FOR PROPOSED CHANGE Proposed Chance This proposed change will add a footnote to Specification 4.8.1.1.2h(6)(c) that states "The high jacket water temperature trip may be bypassed." This change wil' allow the diesel generators to be operable with the high jacket water tctper.ture trip bypassed.

Eluill Regulatory Guide 1.9 requires that all diesel generator protective trips except engine overspeed and generator differential be either automatically bypassed -

under accident conditions or implemented with two or more independent measurements for each trip parameter. Sufficient operator reaction time should be available for bypassed trips. The Vogtle Electric Generating Plant diesel generators are designed with two additional trips that are not automatically bypassed. These are the loss of lube oil pressure and high jacket water temperature trips. Plant operating experience has shown that the high jacket water temperature trip system is a source of unnecessary diesel generator trips.

Therefore, GPC is preparing a modification that will allow this trip function '

to be bypassed. In conjunction with this modification it is necessary to modify the Technical Specification to indicate that this trip function may be bypassed.

The effects of this change have been evaluated to determine whether or not it involves any significant hazards consideration. This evaluation is presented ,

in Enclosure 2.

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ENCLOSURE 2 i V0GTLE ELECTRIC GENERATING PLANT I REQUEST TO REVISE TECHNICAL SPECIFICATION 4.8.1.1.2h(6)(c) i 10 CFR 50.92 EVALUATION i Pursuant to 10 CFR 50.92, Georgia Power Company (GPC) has evaluated the attached ,

proposed amendment and has determined that operation of the facility in )

accordance with the proposed amendment would not involve significant hazards I considerations.

BACKGROUND 1 This proposed change is to allow the emergency diesel generators to be started l by an emergency signal with the high jacket water temperature trip bypassed. l This is in addition to the other trips which are already bypassed by an i emergency start signal (Safety Injection (SI), Loss of offsite power (LOSP), or j Emergency Manual start). A modification will be made to add isolation valves in the instrument tubing between the DG high jacket water temperature elenients and the local DG control panel. The valves will normally be closed so that high l Jacket water temperature sensors will not provide input to the engine trip J logic, but may be opened to allow additional engine protection when performing a non-emergency manual start or surveillance of the diesels. In order to close these valves the Technical Specifications are being revised to indicate that the jacket water temperature trip may be bypassed.

- Position 7 of Reg. Guide 1.9, Revision 2, states that all diesel generator protective trips should be either bypassed when the diesel generator is required for a design-basis event or implemented with two or more independent measurements with coincident logic provisions. All protective trips are allowed during periodic testing. The allowed exceptions to the above requirements for bypassing are diesel engine overspeed and generator differential current. -

Currently, all the protective trips except engine overspeed, generator differential, low lube oil pressure', and high jacket water temperature are -

l bypassed during an emergency start. The low lube oil pressure and high jacket i water temperature trips are implemented by three independent measurements for ,

each trip parameter. Actuation of these trips is initiated by two-out-of-three coincident logic. These provisions satisfy the requirements of Position 7 of Reg. Guide 1.9 and, as documented in section 8.3.1 of the SER, were found by the '

NRC to be acceptable.

However, to increase the reliability of the diesel generators, it has now been determined that the trip on high jacket water temperature should also be bypassed during an emergency start. Reg. Guide 1.9, Rev 2 allows this trip to -

i be bypassed under accident conditions provided the operator has sufficient time I to react appropriately to an abnormal diesel-generator condition. In addition, the bypass circuitry should satisfy the requirements of IEEE 279-1971 at the DG system leve? snd should include the capability for (1) testing the status and operability of the bypass circuits, (2) alarming abnormal values of all bypass parameters in the control room, and (3) manually resetting of the trip bypass function. (Capabnity for automatic reset is not acceptable.)

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ENCLOSURE 2 (CONTINVED) j i

V0GTLE ELECTRIC GENERATING PLANT -l RE0 VEST TO REVISE TECHNICAL SPECIFICATION 4.8.1.1.2h(6)(c) l BACKGROUND (Continued)

This pro)osed change meets the intent of Reg. Guide 1.9. Abnormal values of i high jac cet water temperature will continue to be alarmed locally and in the  ;

control room. Low Jacket water pressure is also alarmed. From the time of the ,

high jacket water temperature alarm, the operator will have sufficient time to react appropriately to abnormal diesel generator condition. If the valves are closed, the trips will be bypassed. Operating procedures will assure the i correct position of the valves.

ANALYSIS In order to accomodate the current design, the Technical Specifications require verification that all automatic diesel generator trips are automatically bypassed upon loss of voltage on the emergency bus concurrent with a Safety Injection Actuation signal, except for engine overspeed, generator differential, low lube oil pressure and high jacket water temperature. The proposed Technical Specification change will note that the jacket water temperature trip may be bypassed. The high jacket water temperature trip is designed to protect the diesel generator from a loss of engine cooling. For such an event, the safety function would be provided by the diesel for the other train. During an ,

accident, the advantage of the automatic trip is small relative to the increased reliability achieved by reducing the possibility of a spurious trip.

RESULTS This change will not increase the probability of an accident previously evaluated because it does not affect any of the design basis events that have been previously evaluated in the FSAR. The analyses of cccident consequences do not take credit for the ability to restart a diesel following a diesel generator trip. Therefore, this change will not affect the previously evaluated consequences.

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ENCLOSURE 2 (CONTINUED) )

l V0GTLE ELECTRIC GENERATING PLANT i RE0 VEST TO REVISE TECHNICAL SPECIFICATION 4.8.1.1.2h(6)(c) ]

10 CFR 50.92 EVALUATION

, RESULTS (Continued)

The revision to the Technical Specification will not create the possiblity of a new or different kind of accident from any accident previously evaluated. No new modes of operation are being imposed on the plant and the diesel generators will continue to perform their function as designed. .

The revision does not result in a significant reduction in the margin of safety provided for events involving a loss of electrical power. The proposed revision will allow the implementation of a modification which is intended to improve the reliability of the diesel generators by minimizing the possibility of spurious trips.

CONCLUSION Based on the preceding analysis, GPC has determined that the proposed change to the Technical Specifications does nnt involve a significant increase in the probability or consequences of an accident previously evaluated, create the j possibility of a new or different kind of accident from any previously evaluated Therefore, GPC

( orconcludes involve a significant that reduction the proposed changein a margin meets of safety. of 10 CFR 50.92(c) and the requirements does not involve significant hazards considerations.

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