ML19319B788

RO NP-33-77-63:on 770812,absolute Position Indicator for Control Rod 4 Showed Fluctuation Reading.Caused by Defective Relay in Position Indicator Panel.Relay Replaced Returning Absolute Position Indicator to Svc

ML19319B788
Person / Time
Site:	Davis Besse
Issue date:	09/12/1977
From:	Lingerfelter J, Vallade S TOLEDO EDISON CO.
To:
Shared Package
ML19319B691	List: ML19319B690 ML19319B788
References
NUDOCS 8001270256
Download: ML19319B788 (2)

Text

O LICENSEE EVEtr REPORT p.

b

,l,_ L j I !

!__j Comraos stoC=

Naut

~'

L Ct wst Nuwet e i v et t v"pt

@]9[0lH I DIB i S ilj 10 j,0L j Ol 01 NI Pl{l -10 ; 3l l4 l

t jl l l[lj OJ 3{

la ' 15 25 2G s0 t

7 CattCom'

• L

• **

• C P OnCut t Nuuet a r gt h e ria t t etpost cas t p0iCovit y L

lWL_J [01 50._i 0 3l4 1 6 i t 01 8 11;2 1 7l7 1 10 91 11 Lj 1

1 27 17j t

Si ha 59 6a 68 69 7e 75 60 (vtNT Of SCRsPf tom g: The Absolute Positi,on Indicator (API) for Control Rod 4 of Group 4 was l

7 89

@l inoperable. The indicator light for Rod 4 showed that it was 100%

8 89 8 1 withdrawn, but the indicator itself had a fluctuatine readine. This is l

7 89 E Lnot a repetitive occurrence.

OTP-33-77-63) 1 7

89 8L 1

[n"n't

@ l b"t" t e"'

u =7uYa"c"eYn'r a coucows new coor supp voos A reon i [Ej iItNISITIR1Ui

[10

[D 11 I 51 01

[NJ 3

s9 to in 12 17 43 44 47 48 CAUST DESCRIPiioN l Instru:nent and_Cggt.r_o_1 Technicians found that a relay in the Position I

9 l Indicator Panel was defective.

It was replaced by the vendor.

l' 84 e9 O

@ l,

'd

.o c.wis-

.u= :

8 LBJ l0101Gl iga.. _

.. c o... e t s.

..t._

l LAJ

[.. NA J

7 0

9 to 62 1

44 dt 46 80 et D os a'

t m uovM t or A C T e v81.

LZJ, LZJ l NA I

l NA l

LoCatsom ce atttASC 7

3 9

10 Il 44 45 80 PtnSoNNEL EzPoSUAE5 uwwe e

• t vet or se ssatoom Li!3J1 O f 0101 (ZJ l NA 7

89 68 12 13 J

60 Pf nsoaeNEL INJUNIES

~ uw a c..

ni se.....o~

8101 Of 01 1 NA i

1 e) in is 80 o9 9 581t CoNstout NCEs aM Lo35 oM DauaGE la F ACILOIV e w PC ot % C a s* t io**

P. I,IJ L 8^

ar PuttsCITY 8 I n.s I

> e9 A3 ADD 11 TONAL F ACTOR $

31 NA l

s SJ

31..

I p

i sa to Jacque Lingenfelter/ Sue Vallade (4197'259-5000, Ext. 251 DVR # 095-1,129-1 8001270

TOLEDO EDISON COMPANY

(

)-

DAVIS-BESSE UNIT ONE NUCLEAR POWER STATION

/

SUPPLEMENTAL INFORMATION FOR LER NP-33-77-63

_DATE OF EVENT: August 12, 1977 F_ACILITY: Davis-Besse Unit 1

_IDE!TIIFICATION OF OCCURRENCE:

Rod 4 of Group 4 was inoperable.The Absolute Position Indicator (API) for Control Conditions Prior to Occurrence:

The plant was in Mode 2, with Power (MWT) = 0 and Load (M Tr) = 0.

Description of Occurrence: At 1910 hours0.0221 days <br />0.531 hours <br />0.00316 weeks <br />7.26755e-4 months <br /> on August 12, 1977, the Absolute Position Indicator (API) for Control Rod 4 of Group 4 was inoperable. The Control Room operator could not determine Control Rod 4 position within + 6.5%

This placed the Station in Action State =ent 3.1.3.3.

(a) of Technical Specification The indicator light (relative position indicator) for Rod 4 showed that it was 100% withdrawn, but the API reading fluctuated frem 70-100% withdrawn.

the indicator lights and API readings for the other reds in Group 4 shewed 100%

Since thdrawal, it was suspected that the API for Rod 4 was defective Designation of Aeoarent Cause of Occurrence:

Upon investigation, Instrument and Control Technicians round that a relay in the Position Indicator Panel was defective.

Dianond Controls.The relay, along with connecting cable, was replaced by the vendor, Analysis of Occurrence:

public or Station personnel.There was no danger to the health and safety of the The cont nl red was m-+= Thy aligned with the group, and relative indication was still operable.

properly.

The cvuisol rod was operating t

Corrective Action: On August 13, 1977 operability to the API for Control Rod 4the relay was replaced, returning Statenent (a) of Technical Specification 3.1.3.3.This removed the Station from Action

,_+

5 I ;

• i Failure Data:

There have been no previous similar occurrences.

.e

/~~N

{

I

}

{

x x./

t i

g e

a b

I

.