ML20028F439

LER 82-084/03L-0:on 821223,sequencer Initiated Alarm Failed to Clear When Diesel Generator 12 Shut Down.Caused by Failure of Breaker Lever to Operate Auxiliary Switch in Cubicle Due to Displaced Assembly.New Assembly Installed

ML20028F439
Person / Time
Site:	Calvert Cliffs
Issue date:	01/21/1983
From:	Basso L, Junge M BALTIMORE GAS & ELECTRIC CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML20028F433	List: ML20028F432 ML20028F439
References
LER-82-084-03L, LER-82-84-3L, NUDOCS 8302010354
Download: ML20028F439 (2)

Text

NRC FORM 366 U. S. NUCLEAR RE!UL ATORY COMMISSION (7 71) . ,

• 1CENSEE EVENT REPORT (PLEASE PRINT CR TYPE ALL REQUIRED INFtRMATILN)

CONTROL BLOCK: l 1

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i 7 0 1 8 9 l M l LICENSEE D l C lCODE C l te 14l 1 l@[0_d0 15 l- l 0LICENSE l 0 l NUM8ER 0 l 0 l 0 l- l 0 l 0?Sl@l26 4 l LICENSE 1 l 1 lTYPE1 l_ L]@iJO 57 CAT 58 l I@

CON'T 10111 3$n"c'60l L @l61 0 l 5 lDOCKET 0 l 0NUMBER l 013 l 1 l 687 l@l 1 l EVENT 212DATE l 3 l 81274 l@l011 l 2 l DME1 18 l 380 l@

? 8 69 75 REPORT EVENT DESCRIPTION AND PROB ABLE CONSEQUENCES h o 2 l At 1815 during normal operation. f.Le seauencer initiated alarm did not- l J

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clear when 12 diesel generator (DG) was shut down (T.S. 3.8.1.1) . With j l0 l4 l l 11 DG out of service for maintenance, 12 DG aligned to 11 4KV bus.. 11 l l0l5l l Control Roon. Air Conditioner (CRAC) was without an emergency power l 10 le l I source (T.S. 3.0.5). At 1855, 12 DG was aligned to 14 4KV bus and I

{7_l l raturned to service. At 2130, 11 DG was returned to service ord 11 CRAC l l O la J l was declared operable. Similar events: None. I 80 7 8 9 DE CODE S BC DE COMPONENT CODE SUSC D'E S E l TIT,I 7 8 l E-l E lh lE lh lB lh l Cl Kl Tl Bl Rl Klh Wh W h 9 D) 11 12 13 18 19 20

,_ SEQUENTIAL OCCURRENCE REPORT HEVISION LE R !Ro EVENT YE AR REPORT NO. CODE TYPE N O.

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_ l218l222l 23 24 26 27 M M- 30 31 32 AK N AC O O PL NT M HOURS 22 S8 I FOR 8. SUPPL 1 R MANUF CTURER l AlgJ@

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35 36 3r 40 41 42 43 l44 Gl 0l 8l 0l@ 47 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS 27 li l0 l l Investigation found the " Sequencer Initiated" alarm hanging due to fail- l i i l ure of a lever on the breaker (General Electric MC-4.76) to operate an 1 i ; l auxiliary switch in the cubicle. A retaining ring holding a cam & link- l 3 _

[i l3l l age assembly Q place hac slipped off, displacing the assemtly. A new l li l4 l l assembly was installed. No further action is planned et this time. l 7 8 9 80 3

ST S  % POWE R OTH ER STATUS IS O SISCOVERY DESCRIPTION W W @ l1l0l0l@l NA l W @l Operator Jbservation l A TlVITY CO TENT RELEASED OF RELEASE M90UNT OF ACTIVITY LOCATION OF RELEASE NA l l NA l M [Jf_]

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@ l:1 44 d5 80 PERSONNEL EXPOdVRES NUMBER TYPE 1 7 l 0 l 0 l 0 lhl Z lhlDESCRtPTIONNA l 7 *

• PERSONNE L INJU IES NUMBER DESCRIPTION 7

i a 8 9 l0l0l0lhl 11 12 NA 80 l

LOSS OF OR DAMAGE TO FACILITY TYPE DESCRIPTION 7

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PUBLICITY 8302010354 830121 NRC USE ONLY ISSUED DESCRIPTION , PDR ADOCK 05000317

• 2 O [N_jhl S PDR l lllllllllllll$

7 8 9 10 68 69 80 5 NAME OF PREPAREHy. A. Angen. F. Basso PHONE: 301-269-4969/4933 , {

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LER NO. 82-84 DOCKET NO.59-317 LICENSE NO. DPR-53 EVENT DATE 12/23/82 REPORT DATE 01/21/83 ATTACIMENT' EVENT DESCRIPTION At 1815 during norrsl operation, upon ecuptation of testing #12 diesel tenerator (DG) on #17. 4KV bus, the "Sequencet Initiated" alarm

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i j did not clear when the diesel output breaker was opened. ,i2 DG was i i declared; inoperable (T.S. 3.8.'1.1) when investigation revealed the sequencer would not initiate as designed. With 12 DG aligned to #11 i 4KV bus, and #11 DG out of service for maintenance, #11 Control Room Air Conditioner was left without an emergency power source. (T.S.3.0.5 and T.S. 3.7.6.1). At 1855, #12 DG was returned to service when it waar aligned to #14 4KV bus.; AcL2015, action was initiated to place the reactor in Mode 3 as per T.S. 3.0.5. At 2130 #11 vG was returned to service,.

1. 11 CRAC was declared ope.*able and the reactor returned to 100% power.

j Similar events: None.

i 9

t CAUSE DESCRIPTION Investigation found that clearance of the "Sequ4ncer Initiated" alarm

was prohibited by failure of a, lever on the breaker (General Electric ,

MC-4.76) to operate an auxiliary switch. mounted in the switch-gear

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cuolcle. A retaining ring that holds the auxiliary switch operating cams and linkag+ assembly in place had slipped off, dislocating the assenbly. The assembly was replaced with_a spare. No cause has been

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i founi.for the failure of the retaining ring.

l Sin <2 this is the tirst such failure, no further preventive action is deemed necer,8ary 1

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