05000259/LER-1980-044-01, /01T-0:on 800602,while Reviewing Instrument Buses Per IE Bulletin 79-27,failure of 250 Volt Dc Battery Board Determined to Cause Feedwater Flow to Increase to Full Flow & Disable Feed Pump Trips.Caused by Power Nonseparation

/01T-0:on 800602,while Reviewing Instrument Buses Per IE Bulletin 79-27,failure of 250 Volt Dc Battery Board Determined to Cause Feedwater Flow to Increase to Full Flow & Disable Feed Pump Trips.Caused by Power Nonseparation

ML19323J229
Person / Time
Site:	Browns Ferry
Issue date:	06/13/1980
From:	TENNESSEE VALLEY AUTHORITY
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML19323J228	List: 05000259/LER-1980-044, Forwards LER 80-044/01T-0 05000259/LER-1980-044-01, /01T-0:on 800602,while Reviewing Instrument Buses Per IE Bulletin 79-27,failure of 250 Volt Dc Battery Board Determined to Cause Feedwater Flow to Increase to Full Flow & Disable Feed Pump Trips.Caused by Power Nonseparation
References
IEB-79-27, LER-80-044-01T-01, LER-80-44-1T-1, NUDOCS 8006190470
Download: ML19323J229 (2)

LER-1980-044, /01T-0:on 800602,while Reviewing Instrument Buses Per IE Bulletin 79-27,failure of 250 Volt Dc Battery Board Determined to Cause Feedwater Flow to Increase to Full Flow & Disable Feed Pump Trips.Caused by Power Nonseparation

Event date:
Report date:
2591980044R01 - NRC Website

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g ; it was detemined that failure of 250V DC battery board would cause feedwater flow g ; to increase to full flow and feed pump trips to be disabled.

Reference FSAR section j

g,14.5.7.

It was initially reported that this postulated event could only occur in j

"A" m de.

Further investigation revealed it could occur in "B" mode also.

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redundant systems. No previous occurrences. No danger to the health or safety of g o g,; g y,the public.

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CAUSE DESCAIPTION AND COHRECTIVE ACTIONS h g l Caused by non-separation of power to feedwater flow control and trip solenoids.

,,, j ; Temporary alteration made to provide unit preferred power to two flow control i

gmodules so "B" mode would be independent of 250V DC.

Established administrative controls

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Investigating ways to permanently separate flow controls and trip solenoid power.

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1/10/79 LER SUPPLEMENTAL INFORMATION BFRO-50-2L/ 8044 Technical Specification Involved FSAR section 14.5.7,

Reported Under Technical Specification 6.7.2.A.8 Data e Occurrence 6/2/80 Time of Occurrence 1545 Unit

1. 2, and 3 Identification and Description'of Occurrence:

While reviewing instrument buses per IE Bulletin 79-27, it was determined that f ailure of the 250 V DC battery board would cause feedwatet flow to increase to full flow and It was initially reported this postulated event could feed pump trips to be disabled.~

only occur in "A" mode. Further investigation revealed it could also occur in "B" mode.

Conditions ' Prior to Occurrence:

Unit 1 @ 81%

Unit 2 @ 96%

Unie 3 @ 100%

Action specified in the Technical Specification Surveillance Requirements met due to inoperable equipment. Describe.

NA Apparent Cause of Occurrence:

No separation of power to feedwater flow control and feed pump trip solenoids.

Analysis of Occurrence:

There was no damage to plant equipment. There was no activity release, no personnel exposure or injury and no danger to the health or safety of the public. This postulated event constitutes an unanalyzed transient resulting from full, uncontrolled feedwater flow and no feed pump trip capability.

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Corrective Action

Upon the review and verbal concurrence of Engineering Design a temporary alteration was made to provide unit preferred power to two flow control modules so that "B" mode operation would be independent of 250 V DC.

Established temporary administrative controls to minimize and control operation in "A" mode. An investigation is underway to determine a way to permanently separate the flow control and trip solenoid power supplies.

Failure Data:

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N/A

• Retention :

Period - Lifetime; Responsibility - Administrative Supervisor

• Revision:

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