05000317/LER-1982-082-03, /03L-0:on 821227,noted Continuous Control Element Assembly Motion Inhibit (CMI) Signal in Effect Causing CMI to Be Inoperable Whenever Control Element Assemblies Moved. Cause Unknown.Cmi Alarm Relay Replaced

/03L-0:on 821227,noted Continuous Control Element Assembly Motion Inhibit (CMI) Signal in Effect Causing CMI to Be Inoperable Whenever Control Element Assemblies Moved. Cause Unknown.Cmi Alarm Relay Replaced

ML20028F416
Person / Time
Site:	Calvert Cliffs
Issue date:	01/21/1983
From:	Raynor J, Wenderlich R BALTIMORE GAS & ELECTRIC CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML20028F405	List: 05000317/LER-1982-082, Forwards LER 82-082/03L-0 05000317/LER-1982-082-03, /03L-0:on 821227,noted Continuous Control Element Assembly Motion Inhibit (CMI) Signal in Effect Causing CMI to Be Inoperable Whenever Control Element Assemblies Moved. Cause Unknown.Cmi Alarm Relay Replaced
References
LER-82-082-03L, LER-82-82-3L, NUDOCS 8302010337
Download: ML20028F416 (2)

LER-1982-082, /03L-0:on 821227,noted Continuous Control Element Assembly Motion Inhibit (CMI) Signal in Effect Causing CMI to Be Inoperable Whenever Control Element Assemblies Moved. Cause Unknown.Cmi Alarm Relay Replaced

Event date:
Report date:
3171982082R03 - NRC Website

text

NRC FORM 366 U.S. NUCLEAR REZULATORY COMMi%)ON (7<77)

LICENSEE EVENT REPORT CONTROL BLOCK: l l

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60 61 DOCKET NUM8ER 68 69 EVENT DATE 74 75 REPORT DATE 80 EVENT DESCRIPTION AND PROBABLE CONSEQUENCES h I o 12 l l During normal power operation at 1750, noted that a continuous l

his condition caused l

ITTT1 l CEA Motion Inhibit (CMI) signal was in effect.

10l4l l CM1 to be inoperabie whenever CEAs were moved (T.S. 3.1.3.1).

The l

10 i s ; I continuous CMI may have been in effect since 12-22-82.

Since CEAs were l

l O lsj l moved several times during this time period, CMI may have been inoperable l

[O [7 l l for brief periods of time from 12-22-82 to 12-27-82.

Similar Events

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44 47 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS h 11 l 0 l l The cause for this event is unknown. Probable cause is the intermittent i

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operation of a given reed switch on #28 CEA's Reed Stack Position Trans-I l i 121 1 mitter (RSPT) causing CMI alarm relay (K-2) to fail.

K-2 was replaced l

l1l3l l with spare from stock. RSPT will be replaced during unit's next refuel-l l114l l ing outage.

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% POWER OTHER STATUS IS O RY DISCOVERY DESCRIPTION NA l

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l 1 l s l W@ l 0 l 9 l 8 l@l A TlVITY CO TENT HELEASED OF RELEASE AMOUNT OF ACTIVITY LOCATION oF RELEASE NA l

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11 l 7 l \\ 0 l 0 l 0 l@[4]@l NA l

PERSONNEL l*MURIES NUMBER

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ITT 1 101010 l@l NA l

7 8 9 11 12 80 LOSS OF OR DAMAGE TO FACILITY TYPE

DESCRIPTION

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1 9 8302010337 830121 NRc OSE ONLY PUBLI TY DESCRIPTION,s PDR ADOCK 05000317 l l I I I I I I I I I I l:1 ISSUED W hl NA S

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8 9 10 68 69 80 5 R. L. Wenderlich/J. W. Raynor NAME OF PREPARER PHONE:

LER NO.

82-82 DOCKET No.

50-317 LICENSE NO.

DPR-53 EVENT DATE 12/27/82 REPORT DATE 01/21/83 ATTACHMENT 1

CAUSE DESCRIPTION LER 82-82 Unit 1 Troubleshoocing revealed that the Control Rod Motion Inhibit (CMI)

~

Alarm Relay (K-2) failed; i.e.,

the moveable relay contacts were binding.

K-2 relay was replaced with a spare from stock. Further troubleshooting analysis attributes the failure of K-2 relay to the intermittent or spurious operation of a:given reed switch on CEA 28's-Reed Stack Pos' tion Transmitters (RSPT). The cause for the RSPT failure is unknown.

As a preventative action, CEA 28 has been positioned one (1) step l

below its electrical upper limit to reduce circuit noise, thereby stabilizing K-2 relay. During the unit's next refueling outage the RSPT WIll be replaced.

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