ML19270H478

LER 79-027/031-0 on 790718:channel C Trips Were Received from Power Level,Thermal margin-low Pressure & Axial Flux Offset.Cause of Intermittent Problem Is Suspected to Be Loose Connection or Faulty Switch Circuit

ML19270H478
Person / Time
Site:	Calvert Cliffs
Issue date:	08/17/1979
From:	Heibel R, Rizzo P BALTIMORE GAS & ELECTRIC CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML19270H473	List: ML19270H472 ML19270H478
References
LER-79-027-03L-01, LER-79-27-3L-1, NUDOCS 7908270485
Download: ML19270H478 (2)

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60 61 DOCK ET NUMBER 68 69 EVENT DATE 74 ?S REPORT DATE 80 EVENT DESCRIPTION AND PROB ABLE CONSEQUENCES h o 2 l At 4:45 p.m. , the followino Channel C trips were received: oower level (hich) . l o 3 l thermal margin / low pressure, and axial flux offset. Channel C T-hot was oscillat- 1 o A ino aoorox. 1 . Channel C T-hot was declared inocerative and oower level (hich), I o s I thennal margin / low oressure and axial flux offset were bypassed in accordance with I o e lT.S. 3.3.1.1. Channel C T-hot was returned to service at 1010 om on 7-18-79. The I ol7 l three redundant channels remained operable durina the event. A similar event was I o 3 i reported in LER 78-44 (U-2) . I 7 8 9 '80 SYSTEM CAUSE C A US E COYP VALVE CODE COOE SL8 CODE COMPONENT CUDE SvaCOCE SU8 CODE O 9 IIIAl@ lEl@ [Ej@ l Il Nl Si Tl Rl Ul@ l Sl@ l Zl@

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! ' I c I l The probler has been intemittent. Svmotons have stoceed orior to locatino the I 1 i cause or while technicians have been troubleshootinc. Suscected causa is innse I

,- l connection or faultv switch circuit. The oroble- status is beinn rncorded on I 3 l"aintenance Reauest No. 0-78-3964 which is scheduled for work durino next refuelino I i A 1outace. At that time cabinet wirinc and switch circuits will be accessible (CONTI i 7 8 9 80 STA S  % POWEa OTHERSTATUS DIS O RY CISCOV ERv 0ESCAIPTION 1 is l E l@ l ll 0l Ol@l NA l l A l@l Ocerator Observation l

• ' " 8 A TIVITY CO TENT RELEASE' #8 AELEASE AMOUNT OF ACTIVITY LOCATION CF RELE ASE i is l Z l h l Z l@l NA l NA i E 9 la 11 44 45 60 PEaSCNNEL EXPOSUA ES NUveEA TYPE DESCRIPTION 39 1 1- 10 01 O l@l Z I@l r1 1 PEASONNE INJUAIES NuveEn OESCRIPTION 7

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uve oc AnepApe, R. P. Heibel & . I2. Rizzo A-cN s . (301) 234-7942/7986

LER N0. 79-27/31.

DOCKET NO. 50-318 EVENT DATE 07-18-79 REPORT DATE 08-17-79 ATTACHME!1T CAUSE DESCRIPTION AND CORRECTIVE ACTIONS: (C0!1T) for lifting and reworkino both soldered and crimoed connections.