ML19320B976

Updated LER 79-025/01X-1:on 790926,main Steam Lines Not Isolated After High Temp Logic Actuation.Caused by Misinterpretation of Tech Specs.Tech Spec Revision Proposed

ML19320B976
Person / Time
Site:	Browns Ferry
Issue date:	07/10/1980
From:	TENNESSEE VALLEY AUTHORITY
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML19320B972	List: ML19320B971 ML19320B976
References
LER-79-025-01X, LER-79-25-1X, NUDOCS 8007150574
Download: ML19320B976 (2)

Text

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LRC FORM 386 U S. NOCLE AR HECUL AT Osw .wuMI5510/4 (7 77, UPDATE JEPORT - PREVIOUS REPORT DATE 10/9/79

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7 li l 0 l 8 l800lh I 8 60 48 OOCst ET NuwsER EVENT Of f.CRIPTION AND PRO 8 ASLE CONSEQUENCES h fo~lTl lDuring normal operation due to variation in interpretation of technical specification , j l o l a l I the main steam lines were not isolated following main steam line high temperature j ITT;n 11ogic actuation within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> as required by Technical Specification Table 3.2. A. l iTTTl IThere was no danger to health or safety of the public. Redundant systems were operablej lTTs 1 IThe unit was manually shut down and main steam isolation valves closed. No previous  ;

I IOIil l occurrences.

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l i t i l lof trip system and channel for the main steam line tunnel high temperature switches. j l 1

g lA technical specification revision for clarification is being proposed. The new i j g l technical specification inter pretation has since been discussed with plant manage- 3 L, ig .l ment, through PORC. .

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. Tennessee Valley Authority F.r.e gr.n Browns Ferry Nuclear Plant BF 15.2 1/10/79 LER SUPPLEMENTAL INFORMATION BFRO-50 Technical Specification Involved 3.2.A 259 / 7925 Reported Under Technical Specification 6. 7. 2 . a. (2) 1525 Unit 1 Date of Occurrence 9/26/79 Time of Occurrence Identification and Description of Occurrence:

Due co variation in interpretation of-technical gecificationF the main steam lines were not isolated within eight hours as required by Technical Specification Table 3.2.A. .

Conditions ' Prior to Occurrence: ,

Unit 1 @ 51%

Unit 2 0 99%

Unit 3 @ 0% refueling outage Action specified in the Technical Specification Surveillance Requirements met due to inoperable equipment. Describe.

MSIV's not closed with eight hours.

Apparent Cause of Occurrence: A half isolation signal was received from the "D" logic due to an apparently faulty temperature switch. A JIWR was reviewed by PORC and placed on main steam line ','D"' to clear the isolation signal and allow safe personnel entry.

While troubleshooting .the logic problem the "A" logic main steam high temperature circuit fuse opened when the "A" channel detector was inadvertently bumped with the bottle of a MSA air pack causing the sensor to ground out. The eight hour clock began at this time based on the interpretation of technical specifications. The reactor

- was shut down at 1859 en 9/26/79 and main steam lines were isolated at 0114 on 9/27/79.

Anaiysis of Occurrence:

There was no damage te. plant eqitioment, no activity released, no personnel exposure or injury, and no hazard to health or safety of the public. Full automatic isolation capability still existed.

Corrective Action: The fuse was replaced on the "A" line returning it to service, and an investigation on the "D" line revealed that cable IPC143 IIB was open and the open

' cable was replaced. During the, investigation cable IPC144 IIB was damaged and was repaired. A technical specification revision for clarification is being proposed.

The interpretation of this particular technical specification has been discussed with plant management through PORC.

Failure Data:

NA'

• Retention: 1.ifetime; Responsibility . Administrative Supervisor feriod

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• Revision:

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