ML20085M740

AO 50-267/75/14:on 750530,engine B of a Diesel Generator Oversped to 1,900 Rpm While Electrical Overspeed Trip Being Set.Caused by Procedure Error.Test Procedure Changed

ML20085M740
Person / Time
Site:	Fort Saint Vrain
Issue date:	06/11/1975
From:	Mathie F, Swart F PUBLIC SERVICE CO. OF COLORADO
To:	Howard E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML20085M739	List: ML20085M736 ML20085M740
References
AO-50-267-75-14, NUDOCS 8311090191
Download: ML20085M740 (4)

Text

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public Service ('omimn,v Cff: T.: M :

4s V, P. O. Box 361, Platteville, Colorado 80n51 s

June 17, 1975 Mr. E. Morris Howard, Director

Nuclear Regulatory Commission Region IV office of Inspection and Enforcement Suite 1000 Arlingtcn, Texas 76012 Ref: Facility Operating License No. DPR-34 Docket No. 50-267

Dear Mr. Howard:

Enclosed please find a copy of Abnormal Occurrence Report No. 50-267/75/14 (Final), submitted per the requirenents of the Technical Specifications.

Very truly yours, i

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H. Larry Brer Superintendent-Operations Fort St. Vrain 'cu elear Generating Station HLB:il cc: Mr. Angelo Giambusso hO 8311090191 760903

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PDR ADOCK 05000267 S PDR .c l' v

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REPORT DNLE: June 11.1975 f OCCURRENCE DATE: May 30, 1975 ABN010!AL OCCURRENCE FORT ST. VRAIN NUCLEAR GENERATING STATION 4 PUBLIC SERVICE COMPANY OF COLORADO P. O. 30X 361 PLATTEVILLE, COLORADO S0651, l R7 PORT No. 50-267/75/14 FINAL ,

IDENTIFICATION OF OCCURRENCE:

-Engine B (K-9204X) of A diesel-Generator overspeeded to approximatetly 1900 rpm while the setting of the electrical overspeed trip was being checked. .

This is considered an abnormal occurrence as per Section 2.1, paragraph

(g) of Technical Specifications. -

-CONDITIONS PRIOR TO OCCURRENCE:

Steady State Pcwer Routine Shutdown Hot Shutdown Routine Load Change

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X Cold Shutdown 0,ther (specify) ,.

' Refueling Shutdown Routine Startup The major plant parameters at-the time of the event were as follows:

< Power RTR, O PNth ELECT, O PMe Secondary Coolant Pressure- 1160 psfg Temperature 215 F

-Flow 145,000 #/hr.

PrJmary Coolant' Pressure 351 pnig

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' *F Core Inlet; 3 Tenipera t u re 175' 187 ' *F. Core Outlet._

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Flow ___

305.000 .4/hr.  !

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i DESCRIPTION OF 4

OCCURRENCE:

j The Engine was being run to overspeed by canual control of the fuel rack.

The =echanical overspeed trip was disconnected because of an uncertainty On reaching 4

of its setpoint, believed to be below that of the electrical.

the setpoint of the electrical everspeed trip, the trip actuated, declu -

ching the generator, allowing the engine to run to apprcxi=ately 1900 rpn ,

i before speed uas dec: eased. '

' Maxi =u: engine reco=nended speed is 1650 rpm, normal speed is 1200

- . rpm.

APPARENT CAUSE .

OF OCCURRENCE:

Design Unusual Service Cond. In:luding Invir, Manufacture a Componen:-railure l Installatien/Const. Other (specify) j Operator i X Procedure .

j The procedure called for the engine to be coupled to the generator during test.

The actual trip then shed load off the engine allcwing it to go to overspecd.

j ANALYSIS OF OCCUEiENCE:

When the electrical overspeed trip actuated, declutching the gencrator, fuel flow, cven though shut off quickly, was enough to everspeed the.cngine.

Maxire_: reccerended engine speed is 1650 rpm and the unit reached cpprcxirately 1900 rpm. Disnantling to check possible dcrage (r:;de: Supervisica of,_ manu:ac-to the~crerspcco.

turers service uan) revealed no damage attribut:ble I found, Cylinder ring breakage, piston _ damage, and cylinder liner r.arking This were vill bc attributable to water in the engine at some perled in time.

reported as an unusual occurrence.

CORRECTIVE ACTI ON': ,

The test procedure 'shall be changed so declutch' action vill be checked with the engine at idle, giving no chance of overspeed.

Itens initiating declutching will be checked with the engine declutchel and :the initiating of the signal verified.

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Pags 3 ef 3

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U The test procedure will be thoroughly reviewed for conditions which might lead to equipment damage.

FAILURE DATA /SI3:ILAR REPORTED OCCURRENCES:

Other procedural deficiencies have been experienced, (A0 50-267/75/12 and 13) but no abnorcal engine condition resulted.

The corrective action for these were in progress at the time of this event.

PROGRASCATIC I'?ACT:

Ncne CODE IMPACT:

-None RECO'OIENDED: APPROV"D:

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'l + b %g _ ge,,  :[,. [ . -_ t , cgi Francie.:1. 'Othic, Superintendent 1"rederic E. Swart, Superintendent

!!aintenance buclear Production Fort St. Vrain Nuclear Generating Fort St. Vrain Nuclear Generating Station Station 0