ML19329B900

RO NP-33-74-14:on 770622,safety Features Actuation Sys Channel 1 & Reactor Protection Sys Channel 1 Tripped Due to Shorting to Ground Slide Link,Supplying Ac Voltage to Decay Heat Essential Flow Instrumentation Cabinet

ML19329B900
Person / Time
Site:	Davis Besse
Issue date:	07/19/1977
From:	Batch S, Lingenfelter J TOLEDO EDISON CO.
To:
Shared Package
ML19329B835	List: ML19329B834 ML19329B900
References
NUDOCS 8002060894
Download: ML19329B900 (3)

Text

- . . _.

. . . .....,----: : .n. ' ,

- - - - - '-

~

• 7 ,. *. ,. C

,

-

.

, g .

-

~

• LICENSEE EVENT REPORT

.

.

cONinOLstoCs 1,,L I I I l_j8

-

,

G

f.W!

• L .C c ~,. ~ o... . fut' ' ve.'

,

O

,10 lH I DIB I S il.j . . .s l6j6] j Ojol nip]Fl-l6 1 31 l 4:1111l1j J

- -

- n n , b3d C...co.v w =r: . . . . . . . . .

-

....e.,.... ...o.,om,,

,

40N i l51Op.-ioi 34 i 1 6 pl6: 2:2i7 7 .i 07 l9i 1717 1 IVINr Of SC#88T80N

@l 7 eo Essential Inverter YV1 was accidentally tripped causing losis of j so gl Essential Bus Y1. This resulted in a loss of SFAS Channel k and RPS l 7 o sa EEli Channel 1. (NP-33-77-14)  !

F 89 M E. I.

>

-

.o I

0& { l

-

enamen=e eef coor su E n"' ea aTu"e7c"vS n'r a veos asso e 8189E"l'"3.1" 7 ~60 LAj(nNt lt 1%1 "si 3I5 1 2 16 l 62 17

(_dj i al 31% I3 LN]

4J 44 el as

.

• CAuSF Ot5CRIPTION gl a

Personnel error _ caused a short to ground while closing a slide link. l

@a,l The subsequent loss of Y1 has been deter::ined to be a design proble=

.

m l

7 es o

@l i es and is being inve~stigated by the vendor. . t ao

• g s EN'S ~ os,eeastatus oighoNa w otScovt av Ot;SCnerficae 8

7 0 L3J 9

18i8t to 41 1 32 13 IM 44 i LAJ og lad~NA J 80 at O os $ s'E. aucunt or actsvetv EB IJJ . I _j d I NA I l NA LoCatacas or at tr ast t

7 8 9 to il 44 eg do Ptn50NNat t xP05Unis sevwage e iv*f oE sC o setsoN

,

3 14191 di laj l NA I s 7 9 il 82 43 80 PERSONNil INJustf(3 uuae a. os sc ... .o= -

-

Oldidl NA

.

,, I. .

l

.

Of tSITE CONSEOut NCES is [ NA I5 I N

• LOSS OR DAMAGE 10 # ACILity

• ot s c e ne t so*e

-

NA

.E9. f vrt L . -

i PueLiCity -

• i NA 1

e, - )

.

.

m aOOsttONAt s aC10n5 I'iTel l NA 'Im 9.

O s',/

8.'.

, , , ,

Jacque Lingenfelter/Stan Batch (4197'259-5000, E.st. 251 "3

I

. i'

,

.

8002000 f

_ . . _ . . _ . .u ... _ '. s . . . - . - . . _ . . .

.. ..... .-

~ ~

TOLEDO EDISCN COMPAUY DAVIS-BESSE UNIT ONE HUCLEAR PCiiER STATION p) SUPPLEMEIITAL ILFORMATION FOR LER NP-33-77-14

'NJ

.

,

.

DATE OF EVENT: June 22, 1977 -

FACILITY: Davis-Besse Unit 1 -3

. '

.

IDEhTIFICATION OF OCCURRENCE: .

Ioss of Safety Features Actuation System Channel 1 due to loss of Y1 Conditions Drior to Occurrence:

The plant was in Mode 5, with power ET = 0, MWE = 0.

Description of Occurrence:

On June 22, 1977 at 06 W , an Instrument and Control Technician shorted to ground a slide link which supplied AC voltage to the Decay Heat Essential Flow Instru=entation Cabinet. This caused a loss of Essential Instru=en-tation Distribution Panel Y1, resulting in the tripping of Safety Features Actuation System (SFAS) Channel 1 and Reactor Protection System (RPS)

Channel 1. The Essential Instrumentation Distribution Panel Y1 was

(' supplied by its alternate source YAR, and RPS Channel 1 and SFAS Channel.1 were re-energized at 0720 hours0.00833 days <br />0.2 hours <br />0.00119 weeks <br />2.7396e-4 months <br />.

Designation of Aprarent Cause of Occurrence:

The shorting of the slide link supplying the Decay Heat Essential Flow l

'

Instrumentation Cabinet was due to a personnel error on the part of the Instrument and Control Technician. The loss of Essential Instrumentation l Panel Y1, and subsequent trip of SFAS Cha e l 1 and RPS Channel 1, however,  !

can be attributed to a desi6 n problem in the Inverter YV1.

Analysis of Occurrence:

Since three of four SFAS channels were still operable, and SFAS Channel 1 was tripped, the SFAS would operate if required. The health and safety of the public and station personnel were not endangered. -

.

Corrective Action:

Panel Y1 was supplied by its alternate source, YAR, and SFAS and RFS Channels 1 were re-energized within an hour after tripping occurred. This re=oved the station from the Action Statement' of Technical Specification N 3 3 2.1. The manufacturer has been previously notified as to the defective g ) inverter desi6n, and is working to modify it.

~

%/

_

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

,_ .. . - _ . . _ ,

. - .. , . ,a

.

-

.

i TOLEDO EDISON COMPA!Tf l DAVIS-EESSE tETIT ONE frJCLEAR POWER STATIC!!

. SUPPLEME:frAL INFCRMATION FOR LER NP-33-77-14 - Page 2 l

. .

l 3

. Failure Data: ,

Shorting of slide link has not previously occur;ed, but defective inverter design was partial cause in another event: NP-33-77-6

.

..

.

i 4

t 3

i

{

i i

!

i 1-

!

i i

6

.

,

s i

$

3

'

,

!

!

a

!

2

-

i

.

! .

I I

1

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