05000260/LER-1979-003-01, /01T-0 on 790214:rod Position Info Sys Power Supply Ps X-5 Failed,Causing Loss of Rod Position Indication in Bottom Half of Vertical Core Display.Caused by Failure of Cooling Fan in Trygon Model L5B6-70-OVS4989

/01T-0 on 790214:rod Position Info Sys Power Supply Ps X-5 Failed,Causing Loss of Rod Position Indication in Bottom Half of Vertical Core Display.Caused by Failure of Cooling Fan in Trygon Model L5B6-70-OVS4989

ML18024A698
Person / Time
Site:	Browns Ferry
Issue date:	02/27/1979
From:	TENNESSEE VALLEY AUTHORITY
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML18024A697	List: 05000260/LER-1979-003, Forwards LER 79-003/01T-0 05000260/LER-1979-003-01, /01T-0 on 790214:rod Position Info Sys Power Supply Ps X-5 Failed,Causing Loss of Rod Position Indication in Bottom Half of Vertical Core Display.Caused by Failure of Cooling Fan in Trygon Model L5B6-70-OVS4989
References
LER-79-003-01T-01, LER-79-3-1T-1, NUDOCS 7903050399
Download: ML18024A698 (3)

LER-1979-003, /01T-0 on 790214:rod Position Info Sys Power Supply Ps X-5 Failed,Causing Loss of Rod Position Indication in Bottom Half of Vertical Core Display.Caused by Failure of Cooling Fan in Trygon Model L5B6-70-OVS4989

Event date:
Report date:
2601979003R01 - NRC Website

text

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Z X XQs~l 25 26 LICENSE TYPE 30 57 CAT 58 0

2 2

7 7

9 74

'75 REPORT DATE 80 NBC FORM 3GG LlCENSEE EVENT REPORT s

CONTROL BLOCK:

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tPLEASE PRINT OR TYPE ALLREQUIRED INFORMATION)

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9 LICENSEE CODE 14 15 LICENSE NUMBER CON'T soUBcE LLJQG 0

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60 61 DOCKET NUMBER 68 69 EVENT DATE EVENT DESCRIPTION AND PROBABLE CONSEQUENCES Qlo

~02 Durin normal o eration rod osition information s stem ower su 1

PS X-5 failed

~03 causing loss of rod position indication in the bottom half of the vertical core dis-play (T.S.3.3.A.2.e).

There are no redundant s stems.

Current rod attern was availa-

~05 ble to operating personnel from the computer.

No rod movements were made while the

~OG power supply was out. This is the first failure of this nature.

There was no hazard to

~07 the public health or safety.

80 7

8 SYSTEM

CAUSE

CAUSE COMP.

VALVE CODE CODE SUBCODE COMPONENT CODE SUBCODE SUBCODE

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~E Q12

~E p13 Z

N 3

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0 Qls

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10 11 '2 13 18 19 20 SEQUENTIAL OCCURRENCE REPORT

'EVISION LEBIBO EVENT YEAR REPORT No.

CODE TYPE NO.

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~0$

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~p 21 22 23 24 26 27 28 29 30 31 32 ACTION FUTURE EFFECT SHUTDOWN ATTACHMENT NPRD-4 PRlh'IE COMP.

COMPONENT TAKEN ACTION ON PLANT hIETHOD HOURS +22 SUBMITTED FORM SUB.

SUPPLIER MANUFACTURER Qis ~i/19

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9 33 34 35 36 37 40 41 42, 43 44 47 CAUSE DESCRIPTION ANDCORRECTIVE ACTIONS Q27 o

Failure of the coolin fan in the Tr on Model L5R6-70-OVS4989 ower su 1

caused the ower su 1

to overheat resultin in the actuation of the hi h tern er tection circuit.

A new ower su 1

was installed within 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br />.

This is considered 3

a random failure and no recurrence control action is lanned.

45 7

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FACILITY

~30 hIETHOD OF STATUS

% POWER OTHER STATUS ~

DISCOVERY s

E Qss ~10 0 Qss NA

~AQsl Obsessed 7

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10 12 13 44 45 46 ACTIVITY CONTENT RELEASED OF RELEASE AMOUNTOF ACTIVITY s

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10 44 PERSONNEL EXPOSURES NUMBER TYPE DESCRIPTION Q39

~l> ~00 OJQs7 ~ZQss NA 7

8 9

11 12 13 PERSONNEL INJURIES NUMBER DESCRIPTION 41

~OO O Qs NA 7

8 9

11 12 LOSS OF OB DAMAGETo FACILITY TYPE

DESCRIPTION

0 Z Q42,NA 8

9 10 PUBLICITY ISSUED DESCRIPTION 45 L~JCj NA

.,..,,E>>030503'tR LOCATIONOF RELEASE 80 80 80 80 80 PHONE:

80 NRC USE ONI.Y s

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I DISCOVERY DESCRIPTION Q32 by unit operator

I

Form BF-17 BF 15.2 6/09/78 LER SUPPLEMENTAL INFORMATION BFRO 260 /

793 Technical Specification Involved 3.3.A. 2 Reported Under Technical Specification 6.7. 2.A(2)

Date of Occurrence 2-14"79 Time of Occurrence 0440 Unit Identification and Descri tion of Occurrence:

'od position information was lost for all rods on the bottom half of the vertical core display.

Conditions Prior to Occurrence:

Ndbnal operation at 3218 NMt.

Action specified in the Technical Specification Surveillance Requirements met due to ino erable e ui ment.

Describe.

Power supply replaced within 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br />.

LCO requires shutdown if not corrected within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

A arent Cause of Occurrence:

Failed fan on power. supply caused ovex'heating of power supply and trip out on load limit.

Anal sis of Occurrence:

Current xod positions were stored in process computer and no rod moves were made.during the period the display was inoperable.

Corrective Action

New power supply installed within 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br />.

Failure Data:

None px eviously.

Tennessee Valley Authority - Browns Ferry Nuclear Plant