ML20085M571

AO 50-267/75/23:on 750916,essential Electrical Cable Discovered to Have Failed.Caused by Circumstances Associated W/Work in Progress.Damaged Cable Replaced

ML20085M571
Person / Time
Site:	Fort Saint Vrain
Issue date:	09/26/1975
From:	Hillyard H, Lambert D, Swart F PUBLIC SERVICE CO. OF COLORADO
To:	Howard E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML20085M570	List: ML20085M565 ML20085M571
References
AO-50-267-75-23, NUDOCS 8311090011
Download: ML20085M571 (5)

Text

_ .__ _ _ _ _ _ _ _ _ _ . _ - _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

.. ,b F. O. Box 361, Platteville, Colorado 80651

. September 26, 1975 Mr. E. Morris lloward, Director -

f5k?h,N y ,(' .?.

Nuclear Regulatory Commission ' ~

' c- (;,/k ., t:f.' ' 'j

, Region IV . -

Office of Inspection and Enforcement {

' Q,,,

s p[ .

Suite 1000 ]

7 .(,

Arlington, Teus 76012 c. -

^

\j 9 ::7 Raf: Facility Operating' License , ,.

No. DPR-34 '* M ,2

Docket' No. 50-267 gg

Dear Mr. Howard:

Enclosed plaase find a copy of Abnormal Occurrence Report No. 50-267/75/23,

. Final, submitted per the requirements of the Technical Specifications.

Very truly yours, Fredetic E. Swart Superintendent, Nuclear Production Fort St. Vraig Nuclear l Generating Station FES/alk cc: Mr. Roger S. Boyd e

8311090011 751222 -

PDR ADOCK 05000267 s PDR

~

C()PY SENT REGION I _

/d9(&v _

r f REPORT DATE:

O Septerber 26, 1975 o.

ABNORMAL OCCURRENCE 75/23' OCCURRENCE DATE: September 16, 1975 _ -

M)RT ST. VRAIN NUCLEAR CENERATING STATION PUBLIC SERVICE COMPANY OF COLORADO P. O. BOX 361 PLATTEVILLE, COLORADO 80651 REPORT No. 50-267/75/23 Final .

. ,1DENTIFICATION OF , '

OCCURRENCE:

On September 16, 1975, at 1700 hours0.0197 days <br />0.472 hours <br />0.00281 weeks <br />6.4685e-4 months <br />, an essential cicctrical cabic was discovered to have failed. This was identified an an abnormal occurrence Further per Section 2.1 (f) of the Fort St. Vrain Technical Specifications.

investigation indicates that the initial evaluation was incorrect, and that this should have been catagorized as an Unusual Event.

CONDITIONS PRIOR TO OCCURilENCE: Steady State Power Routine Shut doun ,

llot Shutdown Routine Load Change X Cold Shutdown Other (specify) .

Refueling Shutdown Routine Startup The r.iajor plant parameters at the time of the event were as follows:

Power RIR O )Mth

. ELECT 0 PMc Secondary Coolant Pressure 200 psig Temperaturc 80 *F Flow 400,000 _ #/hr.

Primary Coolant Pressure 12,.8 psia Temperaturc 84 *F Core Inlet 84 *F Core Outlet Flow .' 0 f/hr.

S S

f -

O .

. O' ABNORMAL OCCURRENCE 75/23 Page 2 of 4 DESCRIPTION OF OCCURRENCE:

On September 16, 1975, the control room operators received an alarm indi-cating that the 480V feed to battery. charger IB had tripped open (reference figure 8.2-8.) "

The shif t supervisor on duty proceeded to the.480V switchgcar room to inves -

4 tigate and upon entering observed smoke and the odor of burnt insulation.

Two construction electricians had been " chasing cables" in the area and i ,

reported to the shif t supervisor that while pulling on cable number 3525, they had observed a large ilash.

APPARENT CAUSE OF OCCURRENCE: Design Unusual Service Cond.

Including 1:nviron.

Manufacture Component Failure Installation /Const. X Other (specify)

Operator Circumstances associated with Procedure work in progress.

1 ANALYSIS OF

) OCCURRENCE:

investigation revealed that cable number 3525 is the 480V feed from 480V essential bus number 3 to. battery, charger 1B. The two construction elec-tricians had been in the process of verifying the routing of cabic number 3525 and in so doing, had found it necessary to pull on this cable. In the process of pulling on this cable, the cable shifted in the cabic tray and 4

contacted the sharp metal edge of a cable tray hanger. Unaware that the cable was in contact with this sharp edge, the electriefane continued to pull on the cable, and in doing so, cut throEgh the cable insulation allowing the conductor to contact the grounded hanger', tripping the battery charger feed breaker open. -

CORRECTIVE ACTION:

The damaged cable will be replaced during the effort to correct essential-cable separation and segregation. .

i O

e e

,9 3

I;

~

, j

T **m, .x>- . ] >g - I. n

=  ;

• Uy 73 ,

• J l~y

. . *! . s I

S 3.

.3 . 10 - -

1:: -.

r>

s n1

. m

--s-I.

,!! Y o 55 }

ij.

y s-  :- -

• sp  :- -

. 3 3

• m7

'  :! 3 .

r. 5 I i. U e

n . bD= v

• y s L,  : s o. b.

ms.  ;!

s ;- n-

=- -. v>

t. o "l, 2,:,1, _ .

s. -

it  ! 4 zs 5

• • s  : . P.3 in

• i ut  :: -a , 3

~

igi 1:

~

.r-e:

1. a.

3, /~b 'u x ::

.W i J E.

'l s. s\

. ,u :1 ns s.:.

. g i.-. ,-.

.s 3-EI:'

i "

}. 4.s -  ;- gho

< fe e .

s.

=

1 I g g,)j  :

• .qo * - --s ::,.

5 e

u

g. n

, - -- g::

• u e.j is :. g -o p o g a.

-- ~ n.g ~ ;< n gq asu eg 5p:

e-f: .

4'

- t

-Ov 5 *hs -

=I'  !! ABNOPJiAL OCCURRENCE 75/23

? Page 3 of 4 gh 9 $;4i m^..d$

A. I - -

$O I b e .

ri e T.

• w y a 2

EII p=.

4

• {

ed 8 W SI e , A+-> < g, . g.

3

. - e.

C a.

E e 1*Eg f

<- fg*

5 ga;

> W l$ 0-fo* EE g"4  :

g a ", -x-.Qy,-

• g E ..

f,. . , s

-M .> -

f h er.

s,s _ s. - .

3m .

t,p<:x.

s c.n.>;

.Er E}g 2+

A g . k, **

g;i rE-n V & ,,, n+W Eu

h- ;r

-y 1 -os

--:~^f E

. 1.

g,;*'. -tf

• Ef* W E. 9

-= I. g e' * .

7

• l .

" L.,

e S 5 5 E5,

• 2 lhi_

rs 4*

,' es

,g.r 4.>. $

el-

==

p O

'gD*

I  : e y .Q. 6 eg L.o.J -<<. n .P N -

- o;;i!_

3 & g' g l. C

ABNOR!!AI, OCCURRENCE 75/23

- Page 4 of 4 FAILURE DATA /SIMil.AR REPO'RTED OCCURRENCES:

None A

PROGRA$fATIC IMPACT:

None CODE IMPACT:

None Submitted By: I h[

HarveyW.Ih'41 yard,$f.~- _

Technical Services Supervisor Reviewed By:

Duane Larabert Supervisor, Denver Plant Electricians .

l I

.y , * ,4 1 r-r _

Approved by: _

gg..s St Frf deric E. Swart SAperintendent, Nuc1 car' Production a

em 4

S e

b 5 e ,

9 9

9 9

9

.