05000366/LER-1981-085-03, /03L-0:on 810904,while Operating in Steady State Condition,B LPCI inverter,2R44-S003,tripped.Caused by Failure of Voltage Regulator on Gate Firing Module in Inverter Leg 7.Inverter Leg Replaced

/03L-0:on 810904,while Operating in Steady State Condition,B LPCI inverter,2R44-S003,tripped.Caused by Failure of Voltage Regulator on Gate Firing Module in Inverter Leg 7.Inverter Leg Replaced

ML20010H816
Person / Time
Site:	Hatch
Issue date:	09/15/1981
From:	Coggin C GEORGIA POWER CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML20010H805	List: 05000366/LER-1981-085, Forwards LER 81-085/03L-0 05000366/LER-1981-085-03, /03L-0:on 810904,while Operating in Steady State Condition,B LPCI inverter,2R44-S003,tripped.Caused by Failure of Voltage Regulator on Gate Firing Module in Inverter Leg 7.Inverter Leg Replaced
References
LER-81-085-03L-01, LER-81-85-3L-1, NUDOCS 8109290319
Download: ML20010H816 (2)

LER-1981-085, /03L-0:on 810904,while Operating in Steady State Condition,B LPCI inverter,2R44-S003,tripped.Caused by Failure of Voltage Regulator on Gate Firing Module in Inverter Leg 7.Inverter Leg Replaced

Event date:
Report date:
3661981085R03 - NRC Website

text

_ _ _ _ _ _ _ _ _ _ _ _ _ - _ _ _ _ _ _ _ _ _ _ _ - _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

PRC F r RM 366 U.S. NUCLEAR REGULATORY COMMISSION (7 77)

LICENSEE EVENT REPORT c

CONTROL BL')CK: l l

l l

l l lh (PLEASE PRINT OR TYPE ALL REQUIREG INFORMATION) l 6

l0l1llGl AlElIlHl 2l@l0l0l-l010lOl010l-l010l@l4l1l1l1l1l@l l

l@

7 8 9 LICENSEE COOE 14 15 LICENSE NUMBEM 26 26 LICENSE TYPE JO 67 CAT 68 CON'T ITITl 3E $ lL l@l 0l 5l 0l 0l 0l 3l 6 l 6 l@l 0 l 9 l 014 l 8 l 1 l@l 0l 9 l l l 5 l 8 l 1 l@

7 8

60 61 DOCKET NUMBER 68 69 EVENT DATE 74 75 REPORT OATE 80 EVENT DESCRIPTION AND PROS ABLE CONSEQUENCES h 10121 Mhile operating in a steadv state condition at 1711 MWt on Sentember 4.

I O 3 11981, at 0445 CDT, "B" LPCI inverter, 2R44'-S003, tripped.

This resulted l [O i4; p.n an eight hour LCO per Tech. Spec. 3.8.2.1.

LPCI iniection valve 2 Ell-l f017B is powered by Essential MCC 2R24-S018B and therefore, loop "B" was l O s iO is i pade ir,perable when the event caused it to become de-energized.

2R24-I m IS018B was transferred to the alternate supply.

Plant operation and the I

i O n i health and safety of the public were not affected:

Non-renetitive eventi 80 7

8 9 E

CODE S BC E COMPONENT CODE SUB ODE SU E

l0l9l lE lD l @ [ EJ @ [_A l @ l G l E l N lE l R l Aj@ y @ [_Z_j @

7 8

9 10 11 12 13 18 19 20 SEQUE NTI AL OCCURRENCE REPORT REVISION LE R EVENT YE AR REPORT NO.

CODE TYPE N O.

O ag g,RO I 81 11 l-J 10i8 51 LcJ 10131 ILI l-J l_0 l s

_ 21 22 23 24 26 27 N

29 30 31 32 AK AC O ON PL ANT MET HOURS S e IT FO b B.

SUPPL MANUF CTur R l ^_J@l Z J@

dj@

dj@

l 0l 0l 0l 0l lY lg l Nlg

[_Ajg l El 3l 5l 5lg 33 34 35 36 31 40 di 42 43 44 47 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS h iieOi lEhe event was the result of a failure of the voltage regulator on the I

iiiii gate firing module located in inverter leg number seven.

The inverter I

ieg was replaced with a new one, proper operation of the inverter veri-l l

g lEied and the inverter returned to service.

The unit is in full compli-l ii ni pnce and no further reoorting is required.

l 7

8 9 80 S

% POWER OTHER STATUS IS O Y

DISCOVERY DESCRIPTION g [E J@ l 0 l 7 l 0 l@l NA l

g gl Operator Observation l

TlVITY C TENT ttELEASED OF RELEASE AMOUNT OF ACTIVITY LOCATION OF RELEASE U_La.] lZ_1 @ LZ_}@l NA l

l NA l

PERSONNEL EXPOS ES oESCRiPriON @

NUMBER TvPE fi l 71 10 l0 101@lZ l@l NA l

ERSONNa'iN>u'd,ES oESCn, prion @ NA NuMaEn Ut_J1010l0!@l l

7 8 9 11 12 80 TYPE DESCR PT ON [IE [Zjg!

NA l

7 8 9 10 80 iS$g ESCRIPTION I )109290319 810915 I

IIIIIIIIIIII F

'8 8

' PDR ADOCK 05000366 S

...,, fDR,y n C. L. COggin - Supt. Plt. Eng. Serv.

G3&MH

[

,ggy,

LER #:

50-366/1981-085 Licensee:

Georgia Power Company Facility Name:

Edwin I. Ilatch Docket #:

50-366

Narrative

Report for LER 50-366/1981-005 4

While operating in a steady state condition of 1711 MWt. (535 MWe) on September 4,

1981, at 0445 CDT, "B"

LPCI inverter, 2R44-S003, tripped.

This resulted in an eight hour LCO per Tech.

Spec.

3.8.2.'1.

The caused a loss of power to trip (MCC) essential Motor Control Center 2R24-S018B.

Since LPCI injection valve 2E11-F017B is powered by this MCC, tite "B"

loop of LPCI was made inoperabl e.

The alternate source for MCC 2R24-S018B was placed into service while investigation into the loss of the inverter was taking place.

The cause of the inverter trip was determined to be a

failure of the voltage regulator on the gate firing module located in inverter leg number seven.

Initial investigations indicated that two diodes in that same inverter leg were also defective.

For this reason the entire inverter Icg was replaced with a new one and the inverter was returned to service.

Further troubleshooting of the defective inverter leg revealed that the only defective component was the voltage i

regulator on the gate firing module.

The failure of the voltage regulator is a non-repetitive occurrence and did not affect either of fhe inverters on Unit 1 or the remaining inverter on Unit 2.

t I