ML18344A400

LER 1976-033-01 for Palisades, Low D-C Voltage

ML18344A400
Person / Time
Site:	Palisades
Issue date:	11/03/1976
From:	Bixel D Consumers Power Co
To:	James Keppler NRC/IE, NRC/RGN-III
References
LER 1976-033-01
Download: ML18344A400 (4)

Text

, .

consumers

• Power company General Offices : 212 West Michigan Avenue, Jackson, Michigan 49201

• Area Code 517 788

• 0550 November 3, 1976 Mr James G Keppler Office of Inspection & Enforcement Region III US Nuclear Regulatory Commission 799 Roos evelt Road Glen Ellyn, IL 60137 DOCKET 50-255 , LICENSE DPR PALISADES PLANT - LOW D- C

• VOLTAGE - ER 33 Attached is an event report which relates to the Palisades Plant. This event relates to one of two redundant d-c buses which provide power, through an in-

• verter, to preferred a-c buses . This event occurred during a routine shutdown of the plant.

Assistant Nuclear Licensing Administrator NOV 8 1976

J ,

• LICENSEE EVENT REPORT

• CONTROL BLOCK : I I I I I I [PLEASE PRINT ALL REQUIRED INFORMATION) 1 6 LICENSEE LICENSE EVENT NAME LICENSE NUMBER TYPE TYPE

@E] IMI rlPIAILl1I I olo I-lo Io I olo I ol-1 ol ol l411l1l1l1I Io I 1 I 7 8 9 14 15 25 26 30 31 32 REPORT REPORT TYPE - SOURCE DOCKET NUMBER EVENT DATE REPORT DATE

@E)coN'T I 5"-7---5~9 I 1.!J ~ 1015101-101215151 1110121011161 l1l1lol3l1l6I 7 8 59 60 61 88 69 74 75 80 EVENT DESCRIPTION lo(21 I During shutdown of the plant, d-c bus No 2 voltage dropped to about 60 volts. This I 7 8 9 80 lol31 I in turn dropped the voltage on the two associated a-c preferred buses to about 90 I 7 8 9 BO lol41 I volts. The control room personnel were alerted to the problem by dim annunciator I 7 8 9 ' 80 lol51 I panel lights. The undervoltage relay 74-D2 was not observed to operate although a I 7 8 9 80 lolsl I performance test conducted later showed its operation (Contd on Attached Sheet) I 7 8 9 PIWE (ER-76-33) 80 SYSTEM CAUSE COMPONENT COMPONENT CODE CODE COMPONENT CODE SUPPl.£R MANUFACTURER VICJLATDN 7

@01Elcl 8 9 10 W

11 lclKITIBIRIKI 12 17 W43 lwl1l2lol 44 47 w48 CAUSE DESCRIPTION lolal I The ap12arent cause was due to improper coordinat ;ion of the batteri char~er current I 7 8 9 80 lo Isl I limi:teI: and :t:b.e cba.:c:ge;c: QllL:Cll:t bi: ea.keI: se:t:tfog, I:t bas been CQnCJllded :tba:t :tbe I 7 8 9 80 IT@) I starting of an oil lift pump earlier in the day was the most (Contd on Line 18) I 7 89 80 FACILITY METHOD OF STATUS  % POWER OTHER STATUS DISCOVERY DISCOVERY DESCRIPTION EEJ8 7 9 Lci Io 10 I o I 0112 13 NA 44 I ~

45 I

46 NA 80 I

FORM OF ACTIVITY CONTENT rn8 w RELEASED OF RELEASE AMOUNT OF ACTIVITY LOCATION OF RELEASE 7 9 WI 10 11 NA 44 I 45 NA 80 PERSONNEL EXPOSURES NUMBER TYPE DESCRIPTION 7

!2m8 9lololol11 w12 13 NA 80 PERSONNEL INJURIES NUMBER DESCRIPTION NA EE1 I 0 1° I 011I 7 89 12 80 PROBABLE CONSEQUENCES

~ I None. Other safety systems were available.

7 8 9 80 LOSS OR DAMAGE TO FACILITY TYPE DESCRIPTION 7

Efil8 9~ 10 NA 80 PUBLICITY E08 9 7

None.

80

• ~

7 8 9 illfil89 7

I ADDITIONAL FACTORS (Contd from Line 10) likely cause of the output breaker trip.

80 BO I

• Event Description continued from Line 06 (ER-76-33) to be satisfactory. In an effort to isolate the problem, preferred a-c bus Y20 was isolated. The redundant charger (No 2) was energized and the bus returned to normal. The original charger was also reconnected to the bus to share the charging load. Additional corrective action taken or planned included (1) review of the charger output breaker settings and the charger current limiter settings to assure that they are properly coordinated, (2) a visual inspection of all a-c relays associated with the Y20 and Y40 buses (required to be energized to trip), and (3) provide a separate annunciator light to alarm battery under voltage .

TLX CONSPOWIR JKN 3 1) r-ZCZC Gl7 DLY JAC KSO N MICH 10 / 21/76 ,

AC ~

PMS K W BAKER ~ *-

'I .. . .

NUCLEAR REGULATORY CO MM ISSION <FORME RLY AE'C)'* ,

799 ROOSEVELT RD GLE NN ELLYN, IL (p{)j j *j THI S TWX CO NFIR MS TELEPHONE NO TIFICATIO N OF K W BAKER, RE SI DE~I . ___ ,,__ *-*

-*~

I NSPE CTO R , AT 1049 , 21 OCT r 6, OF A PRO CPER T.S. 6.9. 2 A" 7")

BY K W BERRY, PLANT TECHNICAL SUPT.

AT APPROXIMATELY 1730, 20 OCT 76, LOW VIDLTAGE WAS DISCOVERED ON

,.....,.-. _ _125 V DC BUS D20. IMMEDIATE INVESTIGATION REVEALED LOW VOLTAGE ON PREFERRED AC 'BUSES Y2'0 AND Y40 W CTSSIVE :C:URRE--Nl DRAWN - - - - - -

SF-1201 (R5-69)

QCT 2 7 1~fb BY Y20. EXCESSIVE CURRENT WAS ALSO BEING DRAWN FRO M THE R~SP E'. ~TIV STATION BATTERY NO. 2. BOTH BATTERY CHARGER BREAKE RS 72-2 5 A , 72- 22 WERE FOU ND TO BE OPEN. BOTH CHARGERS WERE CONNECTED AND CO N DI~ IO NS RETUR NED TO NORMAL BY 2000, 20 OCT 76. INVESTI GATIO N IS I N P OGRESS .

J G LE WIS/K W BERRY PALISA DES PLANT CO NSUMERS POWER COMPANY CBW NN NN SF-1 201 (RS-69)