05000318/LER-1979-049-03, /03L-0:on 791221,during Steady State Operation, Channel B Thermocouple Taken Out of Svc Due to Erratic Indication.Caused by Broken Lead on Current Loop Resistor, Vishay Model S-106C.All Loop Connections Checked Quarterly

/03L-0:on 791221,during Steady State Operation, Channel B Thermocouple Taken Out of Svc Due to Erratic Indication.Caused by Broken Lead on Current Loop Resistor, Vishay Model S-106C.All Loop Connections Checked Quarterly

ML20148B976
Person / Time
Site:	Calvert Cliffs
Issue date:	01/21/1980
From:	Lagiewski J, Rizzo P BALTIMORE GAS & ELECTRIC CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML20148B975	List: 05000318/LER-1979-049, Forwards LER 79-049/03L-0 05000318/LER-1979-049-03, /03L-0:on 791221,during Steady State Operation, Channel B Thermocouple Taken Out of Svc Due to Erratic Indication.Caused by Broken Lead on Current Loop Resistor, Vishay Model S-106C.All Loop Connections Checked Quarterly
References
LER-79-049-03L-01, LER-79-49-3L-1, NUDOCS 8001240425
Download: ML20148B976 (2)

LER-1979-049, /03L-0:on 791221,during Steady State Operation, Channel B Thermocouple Taken Out of Svc Due to Erratic Indication.Caused by Broken Lead on Current Loop Resistor, Vishay Model S-106C.All Loop Connections Checked Quarterly

Event date:
Report date:
3181979049R03 - NRC Website

text

v.nu LICENSEE EVENT REPORT l

CONTROL BLOCK: l l

l l

l l

lh (PLEASE PRINT OR TYPE ALL REQUIRED IMFORMATION) 1 6

lo lil l MI ol cl cl NI 2l@l 010l -l Ol Ol Ol Ol 01 -l 01 Ol@l 4 l ll ll ll ll@l I

l@

7 8 9 LICENSEE CODE 14 15 LICENSE NUMtBER 25 26 LICENSE TYPE J0 57 CAT 58 COM'T lolil "Z [L J@] 01 5l 01010131 1181@l 1121 2111719 )@l 0 l 1 l 2 l 1 l 8 ] 01@

7 8

60_

61 DOCKET NUMBER 68 69 EVENT DATE 74 75 REPORT DATE 80 EVENT DESCRIPTION AND PROBABLE CONSEQUENCES h 10 l a i l During steady state operation at 0920, channel B Tc was taken out of I

io i31 I service due to erratic indication. Channel B high power, thermal margin /

1 to ta i l low pressure, and axial flux offset trip units were bypassed per the I

l o I s l I reouirements of T.S. 3.3.1.1.

Channel B hiah power, thermal margin / low.

I io is i i pressure, and axial flux offset trip units were returned to service at 1020 on I

l o l 71 l 12/21/79. Three redundant RPS channels remained operable throughout this 1

Ioi8l l event. LER 77-39 (U-2) describes a sim_ilar event.

I

'E'E

"^'dE

'e'C $'E COvPONENT CooE SUsC70'E SuhEE CO S

loisi lI l A l@ l E]@ l X l@ I I j ft l S l T l R l U l@ l Xl@ [_zJ @

7 8

9 to 11 12 13 18 19 20,

SEOUENTI AL OCCUR R E NCE RE. PORT REVISION -

EVENT YEAR REPORT NO.

CODE TYPE NO.

@ y(u'g p j pol217l9l l-]

l014l9l l/l 1013 l [L_J

[,-j W

tag R "

22 23 24 26 27 28 29 30 31 32 TAK N ACT Q*

ON PL NT MET HOURS S BNi FOR b 8.

SU PLIER MAN FACTURER

[ A_Jgl34z ig l35zl@ Lzj@

l 0l qqq mg l Yl g l3Al@ l Xl 9l 9l 9l@

33 36 37 40 41 42 4

44 47 CAUsE DESCRIPTION AND CORRECTIVE ACTIONS h li lo l l The cause of erratic indication was a broken lead on a current loop resistor, I

li li l I (Vishav Model #S-106C) which develoos a signal voltage for one Tc innut tn I

ii l2j I the Reactor Protective System. All 1000 connections. including this resis tnr.

I l i 131 l are checked cuarterlv undor tho ovis ting Provantivo Wintenanco Drngram.

I l i 14_1 1 1

7 8 9 80 STA S

• . POWER OTHE 9 5T ATUS SO RY OISCOVERY DESCRIPTION l1 15 I l_Ej@ l 1 l 010 l@l ttA l

[1J@l Orera ter 0$s erva,Ltion l

l

'8

',8Tiv TY c$rssi AyOuNT O, ACTIVITY @ l tOCAT,esOPREuASE@

m E.SEo c o Eu iSE flA l

f1A

]

li lo I bj @ LIJ@l 7

8 9 to it 44 45 60 PE 950'.';E L EXPOSUH E S NUYBER+

TYPE

DESCRIPTION

I i i il 1 01 01 Ol@l zl@l tt

__l me.. d'i JE.

') U U j U 24 P oESCR1,rios@

N-eER i

~.

I L2J2J l al ol ol@l ta 7

Q 9 11 12 80 LOSS CF 04 C AYAGE TO FACILITY TYPE CISCRsP13ON L'J oj i zi@l itA l

7 8 9 10 60

{

PUB UCITY NRC UsE CNLY J

8 0 0124 0 /A L

i

,, i iiiiiiiiiij lif[@l flA 4

2 o 7

8 9 10 68 E9 E0 S. La9f ewski/P. G. Rizzo

,ggy g, ( 301 ) 234 -794 2/ 7986 g

NA'/E of PREPARER

..._____m_

l

l,

~

o LER NO.

79-49/3L DOCKET NO.

50-318 EVENT DATE 12/21/79 REPORT DATE 01/21/80 ATTACHMENT CAUSE DESCRIPTION AND CORRECTIVE ACTIONS:

(CONTINUED)

Since implementing this check, the occurrence rate for resistor failures in service has been greatly reduced. No further preventive action is being considered at this time.

l v

i 90030248

=+

- e-

+

= * *