05000259/LER-1979-031-03, /03L-0:on 791112,drywell Air Sampling Monitor,Rm 90-256,observed Alarming Downscale.Erratic Indications Recorded on Previous Occasions.Caused by Failure of Raeco Model 1017 24-Volt Transformer.Transformer Replaced

/03L-0:on 791112,drywell Air Sampling Monitor,Rm 90-256,observed Alarming Downscale.Erratic Indications Recorded on Previous Occasions.Caused by Failure of Raeco Model 1017 24-Volt Transformer.Transformer Replaced

ML19260C145
Person / Time
Site:	Browns Ferry
Issue date:	12/12/1979
From:	TENNESSEE VALLEY AUTHORITY
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML19260C140	List: 05000259/LER-1979-031, Forwards LER 79-031/03L-0 05000259/LER-1979-031-03, /03L-0:on 791112,drywell Air Sampling Monitor,Rm 90-256,observed Alarming Downscale.Erratic Indications Recorded on Previous Occasions.Caused by Failure of Raeco Model 1017 24-Volt Transformer.Transformer Replaced
References
LER-79-031-03L, LER-79-31-3L, NUDOCS 7912180629
Download: ML19260C145 (2)

LER-1979-031, /03L-0:on 791112,drywell Air Sampling Monitor,Rm 90-256,observed Alarming Downscale.Erratic Indications Recorded on Previous Occasions.Caused by Failure of Raeco Model 1017 24-Volt Transformer.Transformer Replaced

Event date:
Report date:
2591979031R03 - NRC Website

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U. S. NUCLEAR REGULATORY COMMISSION NRC FORM 366

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8 6J 61 DOCKET NUMBER 68 69 EVENT DATE 74 75 REPORT DATE 80 EVENT DESCRIPTION AND PROS ABLE CONSEQUENCES h [OTTI I During normal operation, the drywell air sampling tronitor. RM 90-256 was observed alarmi m l ing downscale (T. S. 3.6.C.2). The instrument had indicated erratic recording prior l

l014l lto the event. The chemical laboratory was notified to begin a sampling program whilel IOTil Ithe instrument was out of service. There are no redundant systems. There was no haz-l g g lard to the public health or safety. There have been no previous events of this nature.1 0

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33 31 40 41 42 43 44 47 CAUSE OESCRIPTION AND CORRECTIVE ACTIONS h i

O l RAECO Model 1017 2/*-volt transformer had failed.

The transformer was replaced. and thel 1 1 l system functionally tested and returned to service in seven hours.

No recurrence con-m l trol action is planned since the f ailure appears to be random in nature.

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NAME OF PREPARER PHONE:

4 Tennessee Valley Authority Form BF-17 Browns Ferry Nuclear Plant L F 15. 'J t/10/79 LER SUPPLDENTAL INFORMATION r

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BFRO 259 /_7931 Technical Specification Involved 3.6.c.2 p

Reported Under Technical Specification

6. 7. 2.b. 2 1

Date of Occurrence 11/12/79 Time of Occurrence 0730 Unit i

f-Identification and Description of Occurrence:

RM-9.0-256 alarmed, halogen and iodine channels downscale.

Conditions Prior to Occurrence:

Nomal Operation U-1 100%

U-2 100%

U-3 down for refueling Action specified in the Technical Specification Surveillance Requirements met due to inoperable equipment. Describe.

t Notified chem lab to sample drywell.

Apparent Cause of Occurrence:

F Transformer failure.

Analy_ sis of Occurrence:

There was no da= age to plant equipment, no injury to personnel, no danger to health or safety of the public, no. reduction in power generation.

Corrective Action

Replaced 24V transformer in the instrument, functionally tested and returned the instrument to service at 1410.

Failure Day:

None

• Retention:

Period - Lifetime; Responsibility - Admtnistrative Supervisor

• Revision :