ML20086B195

AO 50-267/74-14A:on 740729,engine B of Diesel Generation Set a Failed to Start.Caused by Tripped Shutdown Mechanism. Caterpillar Co Will Inspect & Adjust Shutdown Trip Mechanisms

ML20086B195
Person / Time
Site:	Fort Saint Vrain
Issue date:	10/31/1974
From:	Mathie F, Swart F PUBLIC SERVICE CO. OF COLORADO
To:	Howard E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
References
AO-50-267-74-14, NUDOCS 8311170095
Download: ML20086B195 (4)

Text

p p

, o v public Eiervice Comp:my CP Cchracb N( P. O.11ox 361, Platteville, Colorado 30651

. p, le'? Yc h GI "'Di' 1s ;p' y.

51, (;

o.s.

frv ,,,$,yn n  ?'

October 31,1974I((Ehi[ / /

4/ jg Mr. E. Morris llovard, Director Directorate of Regulatory Operations Region IV, USAEC 10395 West Colfax, Room 200 Denver, Colorado 80215 REF: Facility Operating License No. DPR-34 Docket No. 50-267

Dear Mr. Howard:

Enclosed please find a copy of Abnormal Occurrence Report No. 50-267/74/14A, Final, submitted per the requirements of the Technical Specifications.

Very truly yours, Ashtslc. Obusd-Frederic E. Swart Superintendent Nuclear Production Fort St. Vrain Nuclear Cencrating Station FES:il s.

cc: Mr. A. Giambusso 95 741031 "" CGn 1

S hK00000267 *

PDR 90PY SENr neo1on -_

l

. p V

O v

11a t c : Oct ght.nyft , 1974 ABNDPmL 0 :CURid:NCE l

TORT ST. YRAIll GUCLl:AR CENEl% TIT!G STATION PliBLIC SURVICE C0'PA'!Y OF COLOPADO P.O. liOX 361 PLATTF.VILLE, COLORADO 80651 PIPORT !!O. 50-267/74/14A Final IDENTIT] CATION OF GCCUf.1gt:CE :

Engine "B" of dieseJ-generation ser "A" failed to start during routine surveillance, July 29, 1974. .

This in considered an abnorraal occurrence per section 2.1 (f) of the ' Technical Spccifications.

CONDITIO::S PRIOR -

Steady State Pouer Routine Shutdown

_TO OCCUPPI':CP.

• llot Shutdoun Routine Load Chcnge X Cold Shutdown Other (specify)

_ Refueling Shutdovn Reactor in heliuri - cyyroyitrat cj Routine Start.up a tmospheri_cJrescttre The taajor plant parar.etern at the titae of the event were as follows:

PTR, O MWth

- Power -

ELE CT , 0 ._ MWe Secondary Collant Presnure O psig Tetaperaturc 0 *f Flow O_ #/hr.

t Pritaary Coolant Pressurc 0 ps1R I Tetapdrature _3_00 *F Core Inlet

__ 100 *F Core Outlet Flow O_ _ #/hr.

t

Pap,c 2 t

lirECRINIO:1 OF

.O.s__C1::

C- _ _ . .4_F"C.I_: :_

• On a routine siert durinn suivcillance tenting, enr.ine "li" of "A" dienel-gener ator cet can prevented fron st artint l'ecause the shutdown ne::unism, actuated by lou oil pressure or engine overspeed, had tripped.

AlPARE::T CAUSE _ Unusual Service Cond.

Design OF OCCC'tCE::CI:. Includine. Environment

!!anu f ac ture

~

_ Corponent Failure Installation /Const. _ Other (Specify)

~

X Operator

._ Procedure -.

Tolerances in the shutdoun ncchenism are such that a trip, as that expericaced, ir a finite, but inprobabic, occurence if the ucchanism is slightly out of adjustncnt.

A:ALYSIS OF OcCt" ": r:

Each tine an engine is taken out of service, the shutdorn nechanisa starts cctuatiny thic to Im oil pressure during engine deccleration. The oil prcasure rmst reach a -redeternined the value to reuct the nechanism during ennine ucchanisn before it reaches the trip point.

acceleration to speed to reset Infrer,uently, the nechanisn travels far enough in its cycle during deceleration that reset et restart does not occur before the nachquisa trips.

COPI_ECTIVE:

Caterpillar Co., the enginer nanufacturer, inforned us that the trip ncchanian could be rmde to travel furthcr in its cycle, by having a longer travel.

This in acconplished by nachining a spacer which governs the start u~

point.

I Further discuccion of the trip ncchanian uith Caterpillar indicates lengthening of the travr1 is not necensary if the nechanisn is properly ad-justed.

Toleranccs, if uithin specifications, thould not cause a false trip.

i luspections and ndiustments as required, of the shutdoun ncchanism l vill be added to the cnr.ine's annual inspection.

1 To insure thnt nl1 four ennines have the trip nechanisu adjusted to satisfactory specificaticus, art:ngencuts have been nade to have a Cat crpillar l

service ran inspect an,i adjunt these ncchauinns, to the reconnended settings.

The engines vill then he tested, uith the service nan present.

P:rp,e 3 s

t e

OCCU!dir':CES :_

FAlLUPP. _1Q\/Sl!!II A!! Itt'JORTr')

llona PROF;PjJP'ATIC 3:! PACT:

None CODP I:! PACT:

1:onc t

a V }-) j.-)fl.M -

, Franh it. Itatitic Superintenlent - !!aintenance f

f *$

i ,

,' < ) wsy,$ G..

g,j'j n ex-[  %\

Approved: '

Luart Ifrederic Sitperintendent E. - Ihiclear l'roducticn A*

l I

l

?

\

I s

1 i

. , _ - , -. - . _ - _ - . _ . . . - - . - . . . - . . , . , - . - _ . - _ . - - .