ML20062G119

/03L-0 on 781117: 5 Halon sub-sys Discharged When Door to 22 Inverter Was Open.Caused by Thermal Detector Being Overly Sensitive to Rate of Rise of Temp.When Door Opened,Internal Airflow Disturbed,Setting Off Detector

ML20062G119
Person / Time
Site:	Calvert Cliffs
Issue date:	12/14/1978
From:	Carroll J, Miernicki M BALTIMORE GAS & ELECTRIC CO.
To:
Shared Package
ML20062G117	List: ML20062G113 ML20062G119
References
LER-78-040-03L-01, LER-78-40-3L-1, NUDOCS 7812260248
Download: ML20062G119 (1)

Text

NRC FOMM 304 . U. S. NUCLE A2 REcVLATO2Y COMMISSION (7771 LICENSEE EVENT REPORT cONTRoLeLoCx:l i

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I 8 23%lLl@l0[5[0l0l0l3i1l8l@l111l1I7I7l8l@l1l2l1!Al7l8l@ 64 69 EVENT oATE 74 75 REPORT oATE 80 60 61 oOCK87NUMets EVENT DESCRIPTION ANo PROBA8LE CONSEQUENCES h ITITl l Durino nomal operation #5 halon sub-system discharced at 0615 on 11/17/78 I o I and again at 0900 on 11/18/78 when the door to 22 inverter was opened. Per i I

o 4 l the reouirements of T.S. 3.7.11.3 a continuous fire watch was established f7TTl I within one hour. The discharged halon cylinder was replaced in each case, I o e I restorino the halon system to full ooerability. All other halon sub-systems I 1o17l l in the cable screadino room remained operable throuahout this event. This I is not a repetitive occurrence. I ee **

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ii io i l Cause of halon initiation detemined to be themal detector which is overly l L'_L'J l sensitive to rate of rise of temocrature. When cabinet door is onened, intern- i

, i al airflow is disturbed, setting off detector. Halon bottles were replaced l

{ g i after both initiations. Detector cannot be adjusted so it is to be reolaced l g l when soare becomes available. No further corrective action is necessary. l

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