ML20099L395

Intervenor Exhibit I-MOSBA-89,consisting of Draft Re Root Cause of 1A Diesel Shutdown

ML20099L395
Person / Time
Site:	Vogtle
Issue date:	09/15/1995
From:	AFFILIATION NOT ASSIGNED
To:
References
OLA-3-I-MOSB-89, NUDOCS 9512280221
Download: ML20099L395 (4)

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D R A F TDCf'XETED US::rg O T ') A W7

, ROOT CAtlSE - 1A Diesel Shutdown Exhibit b ,page l OfI 95 CCT 23 P4 :43 The team believes that the 1A diesel tripped because of a combination of an intermittent failure of a jacket water,. temperature switch and/or inconsistent calibration techniquesZdf ;these Lswf fcfies during 1R2.

annunciator Subsequent testing has shown that' the 3/20/90 diesel indication could be reproduced on a high 3acket water trip. The jacket water trip switches have proven reliable on these and similar enginet between overhauls.

Key Lesson Learned and Recommendations

1. Calibration procedures should be reviewed with the vendor to ensure that calibrations are consistent, and switch performance is reliable.

2. Operator training should be revised to ensure that operators realize that an emergency reset will override the high facket water trip.

3. Maintenance procedures should be revised to ensure that post overhaul control air leaks meet acceptance standards (bubble test performed).

4. The undervoltage s ta rt of the diesel should be changed to bypass non-essential engine trips to improve overall reliability.

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Diesel Reliability In 1989 Vogtle diesels have been rnore reliable than other nuclear industry diesels.

Safety System Perfonnance (Emergency AC Power -- BWR & PWR) 1987 1988 1989 US BQ 0.010 0.009 0.012 US MEDIAN 0.017 0.017 0.020 SISTERS 0.027 0.033 0.030 V0GTLE U1 0.04 0.05 0.006 V0GTLE U2 0.006 PLAINUFPS U

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PDR ADOCK 05000424 g .m 4 q G PDR NUCLEAR REGULATORY COMMISSION Docket No. 50-424/425-OLA-3 EXHIBITNO. Y"b 32 FROn T in the matter of Georais Power Co. et al , Voctie Units 1 & 2 0 6 040 O Staff O Applicant Mtervonor O Other geoceived O Rejected Reporter FD Oidentifig Datedf4 /N Witness 6 70c t' M 0&&

Exhibit M ,page 2 of N I UNIT ONE D/G TRIP SEM503 RISTORY (

SUMMARY

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DATE D/G SENSOR COMMENTS MWO s LO Turbo LO Press Called - failed -

18624684 12/22/86 1A replaced 1PSL-4749D 18806902 10/11/88 1A TSH-19112 - JW Hi Temp Found out of tol.

during PM - recal.

18805581 10/18/88 1A TSH-19112 - JW Hi Temp Found defective -

replaced TSH-19110 & 11 - JW Hi Just PM'ed - found 18807746 11/03/88 1A bad (out of cal.) -

Temp found 2 bad sensors from whse. - finally replaced w/ good f sensors 1PS-19177 LO LO Press Failed cal -

10/08/88

18806912 1B 1PS-19183 -

LO LO Press wouldn't reset 1

3 properly - replaced under 18807392 Hi Main Brng Temp Replaced due to air 4

18807085 10/09/88 1A leaks Sensors G, H, F 18807637 10/27/88 1B 1TSH-19154 HI LO Temp Re-calibrated OK l Wouldn't cal - 1st 2 1TSH-19119 JW HI Temp J

new sw. from whse.

also wouldn't cal -

finally got one from whse. to cal OK 13807793 10/31/88 1B 1TSH-19117 & 18 JW HI Failed - had to Temp replace w/new switches 18906313 12/13/89 1B 1TSH-19154 HI LO Temp Spurious alarm on D/G 1B Control Panel - most likely intermittent switch 92 PROJECT 046041

UNIT TWO D/G TRIP SENSOR HISTORY (S(M4AR g h

• P89ebof[

SENSOR COMENTS Mdo # DATE D/G

/,' 28800543 01/24/88 2A 2X5-4746A Hi Vibration Found venting - replaced Venting - found out of 28800810 02/05/88 2A 2PSL-19114 W Lo Press tolerance - recald 2TSH-19146 Hi Cel checked when connected 28800552 01/25/88 2A to D/G Temp LO 2PSL-4749 A B.C Cal checked - OK 28800918 02/05/88 2A LO Lo Press 2PSH-4744 Hi Cal checked - OK 28800919 02/05/88 2A

' Crank case Press 2PSL-4749 D.E Lo Press Turbo LO 02/26/88 28 2TSH-19153 LO Hi Cal checked - OK 28801450 Temp

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28 2PSL-4859 A.B.C, Cal checked - OK 28801547 02/26/88

' Lo Press LO 02/26/88 2B 2PS-4854 Crankcase Cal checked - OK 28801546 Hi Press 2PSL-4859 0,E, L0 Press Turbo LO 2PSL-19121 W La Press 2XS-4856A D/G Would not trip - Replaced 28802648 04/13/88 28 Eng Hi Vibration ZTSH-19119 JW Found venting - calibrated 28803452 04/20/88 2B Hi Temp 28 2PSL-4859 A.S.C. Cal checked due to Calcon 28805619 06/07/88 Part 21 - no adj. required Lo Press LO 2PSL-4749 A,B,C Cal checked due to Calcon 28805620 06/07/88 2A Part 21 - no adj. required to Press LO 28 2TSH-19117, 18, 19 Engine tripped due to 2 28807390 07/21/88 switches venting - recalibra

' Hi JW Temp 2XS-4745B Turbo Switch malfunctioned and 28819595 12/08/88 2A tripped engine - replaced Hi Vibration 92 F90 JECT ,

04604J L

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/ ExhibitN ,page 4 Of i-I h DATE D/G SDtSOR C(MENTS Found switch venting - replacec 19000016 01/04/90 18 1PSL-4859E Rt Bank Lo Turbo Oil Press 03/01/90 1A Various PM of various trip sensors 1 '

19000439 signed off 3/10/90 2

19000442 03/14/90 18 1TSH-4857E Hi Temp found out of cal high -

Main Brng replaced under norinal PM 19000443 03/05/90 1A ITSH-4747F Hi Temp Found out of cal high -

Main Brng replaced under normal PM 03/22/90 1A IPS-4749A,B,C Lo LO Post Event Investigation 19001433 Press found A switch would not reset replaced all 3 IPSL-19114 Lo JW Cal checked - OK Press 19001482 03/22/90 IB ITSH-4850 Hi Temp Would not cal to within

' LO tolerance - replaced 1TSH-19117, 18, 19 Hi 19117 and 19 were replaced -

19001511 03/24/90 18 Temp JW 18 recaled

' 1TSH-19153 Hi Temp LO Replaced 19001542 03/26/90 18 1PSL-4903 P-3 Cal checked - OK 19001629 03/29/90 1A ITSH-19110, 11, 12 Hi Cal checked - OK Taup JW ITSH-19146 Hi Temp Cal checked - acting sluggish LO replaced 19001677 03/30/90 1A 1PSL-47490,E Turbo L0 Cal checked - OK Lo Press 19001683 03/31/90 1A ITSH-19111, 12 Hi Temp Found venting - replaced JW I

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I 92 PROJECT 046042 l