ML20086A593

Intervenor Exhibit I-MOSBA-40,consisting of to to SD Ebneter Re CAL

ML20086A593
Person / Time
Site:	Vogtle
Issue date:	05/17/1995
From:	GEORGIA POWER CO.
To:
References
CAL, OLA-3-I-MOSBA40, NUDOCS 9507030298
Download: ML20086A593 (5)

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wonone ros ses sssi April 9,19900FFICE OF SECPErTARVa.ewswo DOCKETlNG & SERYlCE

., BRANCH son.e. vee pres.oe u .. cm,m ELV-01516 0012 Docket No. 50-424 g . }2 L} {2 6-M0 O U. S. Nuclear Regulatory Connission Region II 5/f7/95 301 Marietta Street, N. W.

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ATTH: Mr. S. D. Etneter

Dear Mr. Ebneter:

V0GTLE ELECTRIC GENERATING PLAhT CONFIPAATION OF ACTION TETTER  !

ffstte a site area emergency was declared due to a loss ility. of o On March 20, 1990, power concurrent with a loss of onsiteintoemergen Mode 23, 1990 con:erning certain actions we were taking.

t team reput and the appropriate corrective The following discussion provides actions to Mode 2 and subsequent power operation.

. justification for this request. /

In accordance with Vogtle Electric Generating Plant procedures team has The investigated the events leading up to and following the site event review team has presented the results of their review d safe emergency.

j management and those recommendations letter from cons g management poltcy on control and operation of vehicles (see attac George Bockhold to all site personnel); upgrading of emergency network coernunications (see attached letter from George Bockh l Emergency Otractors and Conrnunicators);

both Unit 3 eriergency diesel generator control systems;t barricad

. unnecessary entry into plant switchyard areas; and communicatio i corrective actions related to operations to licensed operators.

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In adottion, the event report also contains a number of longer-ters recosenendations which require additional management review and These include the sequencing of outage activ

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9 NUCLEAR REGULATORY COMM!$SION ge,.qaw-oc4 3 Docttet No. so- wa s-c ' d 4 0#icial Exh. No. 1 **

O in the matter of 6N **"I-StaM IDENTIFIED A;:plicant RECEIVED 7 intarrenor v REJECTED Coarg OffY Contractor DATE 07~/7 4f Other Witness S+:r+lcdecl Reporter C 2'a r

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1 Exhibit- ,page b of

It U. S. Nuclear Regulatory Coenission j

Region II -

i ELV-01516 i Paoe Two The most significant occurrence during the event of March 20, 1990, involved the failure of Diesel Generator (DG) 1A to remain running to support shutdown cooling. The event critique team, ut11tring utility and vendor technical i

experts has investigated the DG failure and provided the following facts:

' a. During bench testing, all three jacket water temperature switches were l found to be set high during the DG maintenance inspection in early March All three were E

! 1990 (by approximately 6-10 degrees F above the setpoint)have differtd from 4 adjusted downward using a calibration technique that may l

that previously used.

i b. Following the March 20 event, all three switches were again bench tested.

j Switch TS 19110 was found to have a setpoint of 197 degrees F which was approximately 6 degrees F below its previous setting. Switch TS 19111 was l found to have a setpoint of 199 degrees F which was approximately the same as the original setting. Switch TS 19112 was found to have a setpoint of i

i 186 degrees F which was approximately 17 degrees F below the previous i

setting and was readjusted. Switch TS 19112 also had a small leak which was judged to be acceptable to support diagnostic engine tests and was

! reinstalled.

c. During the subsequent test run of the DG on March 30, one of the switches (TS 19111) tripped and would not reset. This appeared to be an l intermittent failure because it subsequently reset. This switch and the l leaking switch (TS 19112) were replaced with new switches. All subsequent testing has been conducted with no additional problems.

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d. The Unit 1 jacket water temperature switches have been recalibrated with the manufacturer's assistance to ensure a consistent calibration technique.

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e. Subsequent testing indicated that the diesel annunicator indication of g March 20, 1990 is reproduced on a high jacket water temperature trip.

Based on the above facts, the event review team concluded that the jacket water i

high temperature switches were the most probable cause of both trips on March l 20, 1990.

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TEL PC:1-205-877-7BES us.. rv APR-97 '90 00:48 ID:SONcPCO-V0GTLE Exhibit - ,page ) of i- U. S. Nuclear Regulatory Coanission Region II ELV-01516 Paes Three __

i The following actions are being implemented to ensure a high state of diesel  !

reliability.

1. A test of the jacket water system temperature transient during engine starts l J

was conducted. The purpose of this test was to determine the actual Jacket j water temperature at the switch locations with the engine in a normal J standby lineup, and then followed by a series of starts without The test airthat showed ro111pg jacket 1 the engine to replicate the starts of March 20.

water temperature at the switch location decreased from a standby temperature of 163 degrees F to approximately 156 degrees F and remained steady.

2. Operators are being trained pricr to their next shift to ensure that they understand that an emergency resat will override the high jacket water temperature trip. Giu n u><f/ & M

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3. The undervoltage start feature f the Unit 1 DGs has been redified such that the non-essential engine trips are bypassed. However, alams are still

- provided to inform the operators of off normal enditions. This change will

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. M % Cl be implemented on Unit 2 prior to April 30,1990. > s., ,,A k M i b.u3 1 4. GPC is evaluating the possibility of a design change and Techr#al r#

I Specification change to delete the jacket water high temperature trip as an essential engine trip.

5. GPC has reviewed air quality of the D/G air system including dowpoint control and has concluded that air quality is satisfactory. Initial reports j

of higher than expected dowpoints were later attributed to / faulty instrument,. This was confirmed by internal inspection of one air receiver j

gen April 6,1990, periodic replacement of the contal air filters which l gQ significant water discharge.

f 6. Since March 20, 1990 GPC has performed numerous sensor calibrations j (including jacket water temperaturas), extensive logic testing, special pneumatic leak testing, and multiple engine starts and runs under various f conditions. Since March 20, the 1A DG has been started 18 times, and the 18 i

DG has been started 19 times. No failures or problems have occurred during j

i any of these starts. In addition, an undervoltage start test without air roll was conducted on April 6,1990 and the 1A D/G started and loaded l

properly. Cosoletion of these corrective actions justify GPC's l

determination tsat the DG's are operable.

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t. g U. S. Nuclear Regulatory Commission M' Region II ELV-01516 Pnae Four GPC will continue to work with the Transamerica DeLaval Incorporated thtners ,

I Group to improve DG reliability. GPC will also review possible improvements to protective instrumentation and controls and any additional engine enhancements i

. will be scheduled for refueling overhaul periods. j GPC will continue to work with the IIT and an independent lab to determine the cause of failure of the temperature and pressure switches currently under i quarantine. 1

- Based on the above discussion, we believe we have completed the appropriate 1 d corrective actions necessary to safely operate the unit. We request NRC l 4 approval to enter Mode 2 by close of business on Monday, April 9, 1990.

Should you have any questions, please inquire.

E; $1ncereiy, W. G. Hairston, !!!

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1 Attachment i

xt: Georota Power Cocoany i

Mr. C. K. McCoy i Mr. G. Bockhold, Jr.

i Mr. R. M. Odom

! Mr. P. D. Rushton j NDRMS U. S. Nuclear Reculatery Comission Document Control Desk Mr. T. A. Reed, Licensing Project Manager, NRR l Mr. R. F. Aiello, Senior Resident Inspector, Yogtle i

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