05000296/LER-1979-018-01, /01T-0:on 791030,RHR Pumps 3A & 3C Led to Differential Relay Operation & Interruption of Normal Supply to Shutdown Boards 3EA & 3EB from Unit Board 3A.Caused by Mismatch of Current Transformer Ratios on Normal Supply

/01T-0:on 791030,RHR Pumps 3A & 3C Led to Differential Relay Operation & Interruption of Normal Supply to Shutdown Boards 3EA & 3EB from Unit Board 3A.Caused by Mismatch of Current Transformer Ratios on Normal Supply

ML18024B105
Person / Time
Site:	Browns Ferry
Issue date:	11/13/1979
From:	TENNESSEE VALLEY AUTHORITY
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML18024B104	List: 05000296/LER-1979-018, Forwards LER 79-018/01T-0 05000296/LER-1979-018-01, /01T-0:on 791030,RHR Pumps 3A & 3C Led to Differential Relay Operation & Interruption of Normal Supply to Shutdown Boards 3EA & 3EB from Unit Board 3A.Caused by Mismatch of Current Transformer Ratios on Normal Supply
References
LER-79-018-01T-01, LER-79-18-1T-1, NUDOCS 7911160538
Download: ML18024B105 (4)

LER-1979-018, /01T-0:on 791030,RHR Pumps 3A & 3C Led to Differential Relay Operation & Interruption of Normal Supply to Shutdown Boards 3EA & 3EB from Unit Board 3A.Caused by Mismatch of Current Transformer Ratios on Normal Supply

Event date:
Report date:
2961979018R01 - NRC Website

text

NRC FORM 3{16

{7.77)

LICENSEE EVENT REPORT

. NUCLEAR REGULATORY COMMISSION 7

8 CON'T 7

8 CONTROL BLOCK:

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{PLEASE PRINT OR TYPE ALLREQUIRED INFORMATIONI I

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LICENSEE CODE 14 LICENSE NUMBER oQ38 L i L LQ.~Q5 25 26 I.ICENSE TYPE 30 57 CAT 58

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Oo 60 61 DOCKET NUMBER EVENT DATE 74 75 REPORT DATE 80 EVENT DESCRIPTION AND PFIOBABLE CONSEQUENCES QIO During LPCI logic testing, a simultaneous start of RHR u

s 3A and 3C resulted i differential relay operation which caused an interruption of the normal su 1

to shutdown boards 3EA and 3EB from unit board 3A.

This is contra to FSAR 8 4 4 1 Thexe vere no significant resulting even'ts.

There vas no danger to health or safet 6

of public.

Unit 3 diesel generators were operable.

No previous occurrences.

~O7

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7 8

SYSTEM

CAUSE

CAUSE COMP.

VALVE CODE CODE SUBCODE COMPONENT CODE SUBCODE SUBCODE

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Q14

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10 11 12 13 18 19 20 SEQUENTIAL.

OCCURRENCE REPORT REVISION LER(RO EVENT YEAR REPORT NO.

CODE TYPE NO.

Q11 858583

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+

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~01

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Qo 21 22 23 24 26 27 28 29 30 31 ACTION FUTURE EFFECT SHUTDOWN Q

AT)'ACHhI EN T NPRO.4 PRIME COMP, Coh'IPONENT TAKEN ACTION ON PLANT METHOD HOURS Q SUBMITTED FORM SUB.

SUPPLIER MANUFACTURER

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0 Q28 33 34 35 36 37 40 41 42 43 44 47 CAUSE DESCRIPTION ANDCORRECTIVE ACTIONS Q27 A mismatch exists between the current transfoxmer ratios on the normal su l to the shutdown boards.

Current transformers will be chan ed to ensure ro e

a the ratios, prior to unit return to operation.

No xecurrence control re uired.

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7 8

9 FACILITY STATUS

'A POWER OTHER STATUS Q 5

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8 9

10 12 13 44 ACTIVITY CONTENT RELEASED OF RELEASE AMOUNTOF ACTIVITYQ3 6

~Z Q33

~ZQ34 NA 7

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10 11 44 PERSONNEL EXPOSURES NUMBER TYPE DESCRIPTION Q39 1 ~00 0

011 ~ZQ38 NA 7

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11 12 13 PERSONNEL INJURIES NUMBER DESCRIPTIONQ4)

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Q48 NA 7

8 METHOD OF DISCOVERY

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Operatox 45 46 NA 45 DISCOVERY DESCRIPTION Q32 observed during test.

LOCATIONOF RELEASE Q 80 BO 80 80 n

7 8

9 11 12 LOSS OF OR DAMAGE TO FACILITYQ43 TYPE

DESCRIPTION

Z Q42 NA 9

10 PUBLICITY ISSUED DESCRIPTION ~5

~NQ44 NA 9

10 NAME OF PREPARER 68 69 BO 80 NRC USE ONLY p

83

i'

'I'enny.ssee Valley Authority I3ro~vns Ferry Nuclear

Plant, LER SUPPLER'CMENTAL INFGRI'1A'I'ION For!a DF-1(

BF 15.2

~/10/(9 l3[ RO. 50-296 /

7918 Techn!cal Specificat'ion Involved NA-FSAR 8.4.4.1 Reported Under Technical Specit'icatinn 6 7 2.a (9)

Date of Occu! !ence 10/30/79 Time of Occur! ence 1133 hr Unit iden ification and Beset i~)tion'of Occurrence:

During logic testing associated with LPCI modifications, a simultaneous starting of two RHR pumps occurred causing a different:ial relay operation of the normal supply to shutdown boards 3EA and 3EB.

Conditions Pt it>>

to Vccurr'ence:

U-3 was in refueling shutdown.

U-1 was at 97% power.

U-2 was at 20% power.

Action specified in the Tcchnical Specification Surveillanc Requirements met NA

~PP.'! l eo l.

attse of Occu rect!ce:

A mismatch exists between the-current trans former ratios on the normal supply to the shutdown boards.

The simultaneous starting of the RHR pumps is the only event identification that can cause this differential current to exist.

Aralu'@is ot Ore<!rrence:

There was no damage to plant equipment.

There was no activity release, no personnel exposure or injury, and no danger to health or safety of the public, Co r~ctiv~ Action:

The current transformers will be changed to ensure proper matching of the ratios.

Fallur>." Data:

NA

't'Retention:

'e! iod - I.ifetime; Responsibility

- Administrative Supe! visor

~Revtston