ML19270G039

LER 79-016/03L-0 on 790520:while Inserting Group 5 Control Element Assemblies,Cea 36 Dropped to Bottom of Core.Caused by Spike in 15 Volt Power Supply.Design Mod to Be Installed During Next Refueling Outage

ML19270G039
Person / Time
Site:	Calvert Cliffs
Issue date:	05/25/1979
From:	Davis S, Miernicki M BALTIMORE GAS & ELECTRIC CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML19270G034	List: ML19270G033 ML19270G039
References
LER-79-016-03L-01, LER-79-16-3L-1, NUDOCS 7906010207
Download: ML19270G039 (1)

Text

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1 8 ' M lLICENSEE J D l CCOCE 14 15 ib 26 .t fJ CON'T o i s"E ,3"' l L }@l 0l 5 l 0 l 0 ] 0 ] 3 l 1 l 8 l@l 0 ] 512 l 017 l 9 l@] 0 l 5 l 2 5l7l9l@ 74 50 7 8 60 61 DOCK ET NUYBER 68 69 EVENT CATE 75 HEPORT DATE EVENT DESCRIPTION AND PROBABLE CONSEGUENCES h o 2 At 1142 while insertino aroun 5 control eierent assemblies (CEA's), CEA 36 I o 3  ; drocoed to the botton of the core. In accordance wi th T.S. 3.1.3.1.f, i o I reactor cower was reduced to less than 70% at 1222. At 1242 CEA 36 was l I

o 3  ; withdrawn and realigned with its grouo. LER 78-48 (U-1) and 79-12 (U-2) l 0 s describe similar events. l 0 7 l l o 8 i I

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CAUSE DESCRIPTION AND CCARECTIVE ACTIONS h i o l The droceed rod is assumed to be the result of a soike in the 15 volt oower ii ;ii i sucoly. A desian modification to imnrove the reliability of the system hv i i 7 l installino dual power supplies (FCR 78-72) is to be installed durina the i i 3 l next refuelina outage. I i 4 I I 7 8 9 80 STA S  % POWER CTHER STATUS IS OV RY DISCOVERY CESCR'PTION NA Operator Observation i s l El@ l1 l 0 l 0 l@ l lAl@l l ACTIVITY CO TENT RELE ASEo OF RE LE ASE AMOUNT OF ACTIVITY LOCATION CF RELEASE

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7 e 9 10 33 voos01oKog f 80 2 o t!i ssL E f@ C E SCR:P TION NA i iiilllll ll lI15 7  % 9 to 68 69 80 E JAM CF PHEDARER S. M. Davis /M. J. "iernicki Psc e. (301) 234-7942/7962 g