05000000/LER-1976-010-03, /03L:on 760723,during Start Testing of Emergency Diesel Generator 1,water Detected in Cylinder 7.Caused by Crack in Cylinder Head.Engine Repaired by Replacing Cylinder Head & Head Gasket
| ML20086S445 | |
| Person / Time | |
|---|---|
| Site: | 05000000, Surry |
| Issue date: | 08/02/1976 |
| From: | Baucom T VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| To: | NRC |
| Shared Package | |
| ML20086S443 | List:
|
| References | |
| LER-76-10-03L, LER-76-10-3L, NUDOCS 8403020364 | |
| Download: ML20086S445 (2) | |
| Event date: | |
|---|---|
| Report date: | |
| 0001976010R03 - NRC Website | |
text
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LICENSEE EVENT REPO T
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tCf NSE NUMDER El lv I r I s I pl sl 11 lolo l-l o I ol ol ol 01-10._l 0 l l 4 I 1 11 I i l o l I ol 3l' Nr.V E 25 PG 30 31 32 7 09 14 15 r7rI SINt ooCutt NuMutn EvtNT DAff AFPOAT DAff
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[_LJ,jo l 5 l o l-l 0 l 2 l 81 oj l ol 7l2 l 3 l 7 l 6j l ol 8l of 2l7 l6 l cAftcDay 7 8 57 b6 59 60, G1 60 69 74 75 UO LVENT DESCR:PTIOf4 lDurinn the preparations to test the startfnn of #1 enernency diesel generator (EDCL l
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o 00 diesel nenerator was imediate-l 7 H9
@ l water was detected it.,#7 cylinder. The backup einernency B0
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reonfred l 7 11 9
@ l1v tested satisfactorily and the repairs commenced on #1 EDo. The ennine was 80 7 09 l
@ l by replacing the cylinder head and head nasket. This is a reportabic occurrence in SG 7 09 (USRE-S1-76-10) l
@ laccordance with Technical Specification 6.6.2b (2).
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7 89 pavr CO$f COMPONENT CODE
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fue A VOLATON O
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\\E INl Gl Il N! El [A_,j lElIl4l7i LN.J i
t 7 89 10 11 12 17 43 44 47, 4t3 CAUSE OLSCulPTION Ehp dicsci enti.ne sustained a crack in #7 cylinder head t. hic!l
@ [EMD-GM Turbo Vee 20, 3810 60 ThuswaterfromI) 7 a9 l cxtended between two exhaust valve seats and throuch'the water inchet.
0 60 Q l the cylinder head water jacket was permitted to drip _into the cylinder. (Continued) l y aa c0 I S
s Pentn OTHER STATUS O
VER DISCOVERY OLSCFrP1ON
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W lo151oi I N/A I d l N/A I
1 80 7 8 9
10 12 13 44 45 46 LOCA10N OF REttASE E
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t ES Cf FE. ASE AMOUNT OF ACTM1Y 80 '
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10 11 44 45 PERSONNEL EXPOSURES i
NUMPf H T YF'E Ot SCniP10N I'
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60 7 89 11 12 13 PERSONNEL INJUH;ES l
NuvuTA O(SCFrPTON H 1010101 I
N/A 00 7 89 11 12 OIFSITE CONSEGLIENCES l
@@ l N/A EO 7 U9 LOSS OR DAMAGE TO FACILITY Ivft DE SCRP10N DE lJzj l
N/A 00-7 89 10 PUBLICITY
@l N/A 8403020364 760902 00 7 89 PDR ADOCK 05000290 g
PM ADDITIONAL FACTOnS h-lThebackupemernency dicsc1 rencrator was dem$nstrated to be opernble. Therefore. the l 00 7 B9 (Continued) h l safety systems would have functioned if they'had been recuired.
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_CAUSE DESCRIPTION is0NTINUED)
Inspection of the engine prior to starting permitted detection of the water and prevented further damage to the engine.
This is the sixth cylinder head on this engine to be found with a crack, in a time freme of just over three months.
USRE SI-76-07 listed the other incidents and indicated the probabic cause as either a cylinder heat imbalance or a heat stress as a result of an engine overheat condition at some previous time.
The llocation of /R head on the engine does not conform to the previous pattern and tends to climinate a cylinder heat imbalance as the probable cause.
It appears that a previous engine overheat condition has heat stressed the cylinder heads to such a point that premature metal fatigue from vibration is causing the cracks
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to appear between the exhaust valve seats.
This is an area of high heat and vibration stress.
Toensurethereliabilityofthisengine,theweeklytestingofthisengineas[
outlined in USRE S1-76-07 will continue.
New cylinder heads have been ordered and total replacement should preclude any additional failure. This course of action has been thoroughly discussed with the manufacturer's representative who concurs with this procedure.
ADDITIONAL FACTORS (CONTINUED)
Accordingly, no hazard to the safety or health of the general public existed.
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