ML19281A272

LER 79-006/03L-0 on 790204:control Element Assembly Motion Inhibit Failed to Actuate within Tech Spec Limits.Caused by Bad K2 Relay on Relay Card.Relay Replaced & Inhibit Returned to Svc

ML19281A272
Person / Time
Site:	Calvert Cliffs
Issue date:	03/01/1979
From:	Davis S, Miernicki M BALTIMORE GAS & ELECTRIC CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML19281A270	List: ML19281A269 ML19281A272
References
LER-79-006-03L, LER-79-6-3L, NUDOCS 7903090268
Download: ML19281A272 (2)

Text

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@ P LE ASE F H e N T OR T YPE At L H L Q ulH E D IV O n'.uTIONI

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,'T y g" l L }g 0 l 5 ] l 0 l 0 l 3 l 1 l 8 l]0 r; l 2 E VENT 0 l 4 l 7 l 9 J@LO 14 IS l 0 ICl ATE 7 l 3hEPLnT 9l@ JU b 60 61 .* . T '. s W E R fL DATE EVENT DESCRIPTION AND PRCB ARLE CONSEQUENCtES h p JT] l At 0540 during the perforrance of routine surveillance testina it was dis- _ ]

g ; covered that the CEA ration inhibit failed to actuate within 7.5 inches _j o , [ deviation between CEA's as required by T.S. 3.1.3.1. All CEA's were fully I

o;3; ; withdrawn and the CEA drive system was maintained in manual or off during l

[o y lthe event. CEA motion inhibit was returned to service at 1410 on February I jol,l l6, 1979. LERs77-100 (U-1) and 78-30 (U-2) describe similar events. 1 I

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, SYST E M CAUSE C A USE COVP. VALVE CODE CODE SUSCODE COWCNENT CODE SUSCODE SUSCODE o 9 l R l B !@ [E_j@ l A l@ l I l N l S l T l R I U I8 LcJ@ LLJ @

7 8 9 10 11 12 13 18 19 20 t

SE QUE N TI AL OCCUR R[ NC[ HEFJHT R E VISION LE _ EVENT YE AR R E FOR T NO. CODE TYPE N O.

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27 1013i 2F 29 30 LI 31

-l Lo_J 32 ACTION FUTURE EFFECT SWUTDOWN ATTACHYENT N P R D-4 FalVE CDYP. COYPONENT 1

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43 44 Ml2l8lSl@ 47 CAUSE DESCRIPltON AND CORRECTIVE ACTION 3 h i O lThe CEA motion inhibit failure was due to a t ad K2 relay on the relay card I i i lfor the 8 inch aroun deviation portion of CMI. See attached _shoet for I i , additional details. I 1

3_ l lil_4__] I I i 7 8 9 80 ST s  % PL AER OTHE R ST ATUS SCO i DISCOVERY DE SCRIPTION i s y @ l0l9l8 @l NA l lBl@l Onerator observation l 7 F 9 10 12 Il 44 45 46 80 A C T IVi rY CON T E NT RE ED F AMOUNT O AC Ti t i T Y - L OC ATION OF RE LE ASE 7 8 9 10 11 44 45 BU PERSONNE L f APOSUM ES NLYHE A TYPF OE SCHiP TION 39 r

3 7 8 9 10 10 0l@lzl@l 13 N l 7 11 12 80 FF HSONNE L INJUHIES NueBER Of SCHIPIlON lilsI1010 8 9 0 l@l 12 NA l 7 11 80 t OES OF CH D AVAGE TO F ACILITY .

TvPE DE SCRIP T ION *

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P L!B E iCIT Y NHC USE ONLY te e -( p DE SCHtP T ION l2lOl' '

s  !  ! k 7 8 9 10 68 69 80 %

• * * * ~

N E OF FHEPARER PHONE-

LER 79-06/3L DOCKET NO. 50-318 EVENT DATE 2/04/79 REPORT DATE 3/01/79 ATTACHMENT CAUSE DESCRIPTIO?, '

CORRECTIVE ACTIONS: (CONTINUED)

The CEA motion inhibit failure was due to a bad K2 relay on the relay card for the 8 inch group deviation portion of CMI. The relay was replaced and CMI returned to service. This was detennired to be a natural end of life failure. For several weeks prior to this event there had been numerous spurious actuations of a faulty reed switch on control rod 21. These resulted spurious group deviation alarms, eventually wearing out the contacts of the -

K2 relay. Rod 21 has been positioned by plant operators so as to minimize these spurious alarms. The reed switch stack for rod 21 will be replaced during the next refueling outage.

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