ML20086B439

AO 50-267/74-12:on 740628,turbo-charger on Diesel Engine K-9205X Failed.Caused by Interference Between Turbine & Inlet vanes.Turbo-charger Assembly Replaced & Debris in Engine C Removed

ML20086B439
Person / Time
Site:	Fort Saint Vrain
Issue date:	07/05/1974
From:	Mathie F, Swart F PUBLIC SERVICE CO. OF COLORADO
To:	Gilbert W US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20086B430	List: ML20086B432 ML20086B439
References
AO-50-267-74-12, NUDOCS 8311170223
Download: ML20086B439 (4)

Text

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n- i puhue service company oe odemde i 4- P. O. Box 361, Platteville, Colorado 80651 g.'

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. 't,T @g [5 Mr. William Gilbert i 7920 Norfolk Avenue Bethesda, Maryland 20034

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Facility Operating License No. DPR-34

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Docket No. 50-267

Dear Mr. Gilbert:

1 Em.luned ule.me finid couv of Abitunutil Occiarrence Reparr rin. ..,0-di /'i4/ i d ,

submitted .to the Directorate of Licensing, for your information.

Very truly yours, gp h d d M*

Frederic E. Swart Superintendent Nuclear. Production I

Fort St..Vrain Nuclear Generating Station FES:11 E

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. If?'IT.:* June 28, 1974

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FORT ST. VRAI!I 1:UCLT.AR GFNERATI!'G STNTIO:t PUBLIC SERVICE CC !PA!;Y OF COLORADO

. P. O. BOX 361 PIf,TTEVILLE, COLORADO 80651 .

REPORT 1:0. 50-267/74/12 .

Preliminary [~

Final @

. IDE!!TIFICATIO : OF OCCURRE!!CE: .

The turbo-charger on diesel engine E-92.05X ("C" en;;ine of "B" diesel ncnerator) failed as the unit was being started for survpillance testing Friday, June 28, 1974, at approximately 11:00 a.m.

The failure is considered reportahic under Item 2.1 (f) of the Technical Specifications.

- C0!!DITIOI S PRIOR .

TO OCCURRE!!CE: Steady State Power, Routine Shutdown IIul Siiotdo-n  !;oatinu Luud Chau3c Cold Shutdown Other (specify)

Refueling Shutdown Renctor shut-d_o.:n in liclium Routine Startup ,

atmosphere at atmospheric pressure.

The major plant parancters at, the time of the event ucre as follows:

Power PTR, 0  !!Wth ELECT, O liWe Secondary Coolant . Pressure O psig

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Temperature N/A F Flow nonc #/hr. -

Primary Coolant Pressure O psig-0

• Temperature 135 F Core Inlet.

0 l F Core Outlet .

Flow 0 f/hr.*

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. ng 2

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DESCRIPTION OF ,

OCCURRENCE:

. "B" standby generator unit (driven by "C" and "D" Diesel

• engines was being manually started and loaded for surveillance testing.

As the machine came to speed the,ro'on sta.rted filling with oil smoke from th.c exhaust system. The smoke was thick enough that the ex'act source was unknown.

The operator shut the engines down, and notified maintenance, who dcLermined that lube oil to the blower was leaking into the exhaust, on >

the Ucst bank of "C" engine.

APPARENT CAUSE OF OCCt!RRENCE: Design Unusual Service Cond.

Jncluding Environ, llanufacturc X Component Failurc Installation /Const.

,Other (specify)

Operator I

• Procedurc .

! The Lum bu-cimotet was dismantled and the followis found.

(1) The inlet guide vanes on the exhaust side of the blower had two vancs broken off and missing.

(2) The impeller on the exhaust side was severely rubbed, with the blades fold.ed over. . .

e (3) The drive shaf t was broken between the turbine (exhaust gas side)

, and the impeller (air-side) .

(4) The air side impeller was undamaged.

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The damage was caused by interference between the turbine and the inlet vancs.

Ai!ALYSIS OF OCCURRENCE:

i It-appears as if the inlet vancs on the exhaust gas side broke off and entered the turbine, causing the damage to the turbine, and subsequent drive shaft breakabc.

l The layrinth seal betwcon the bearing and the exhaust gas side was severcly distorted during the rubbing of the turbinc, allowing lube oil to flow to the exhaust.

The resulting smoke partially escaped' the exhaust system, entering the room.

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The entire turbo-charger assenhly was replaced uith another unit.

The turbo-charger on the East bank of "C" engine was opened to check for debris that night have f allen back fron the exhaust af ter the units were stopped. Two small pieces were found and renoved. .

FAIIt!RE DATA /SI!!II.AR REPORTED OCCURRE'!CES The counc of the inlet vane failure is unknown. .

Inspection of the turbo-chargers is scheduled on the annual inspection <

of the units, fio similar occurrences have occurred.

PROGRAF:!ATIC I! PACT Ilo delay was caused by the failure.

CODE II-IPAg None

%nk Frank flathic, !!aintenance Engineer

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.ederic E. Swart, Superintendent m

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