05000259/LER-1979-025-01, /01T-0:on 790926,during Normal Operation,Main Steam Lines Not Isolated within 8-h Following Main Steam Line High Temp Logic Actuation.Caused by Misinterpretation of Tech Specs.Revision of Specs Proposed

/01T-0:on 790926,during Normal Operation,Main Steam Lines Not Isolated within 8-h Following Main Steam Line High Temp Logic Actuation.Caused by Misinterpretation of Tech Specs.Revision of Specs Proposed

ML19253B369
Person / Time
Site:	Browns Ferry
Issue date:	10/09/1979
From:	TENNESSEE VALLEY AUTHORITY
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML19253B367	List: 05000259/LER-1979-025, Forwards LER 79-025/01T-0 05000259/LER-1979-025-01, /01T-0:on 790926,during Normal Operation,Main Steam Lines Not Isolated within 8-h Following Main Steam Line High Temp Logic Actuation.Caused by Misinterpretation of Tech Specs.Revision of Specs Proposed
References
LER-79-025-01T, LER-79-25-1T, NUDOCS 7910150462
Download: ML19253B369 (1)

LER-1979-025, /01T-0:on 790926,during Normal Operation,Main Steam Lines Not Isolated within 8-h Following Main Steam Line High Temp Logic Actuation.Caused by Misinterpretation of Tech Specs.Revision of Specs Proposed

Event date:
Report date:
2591979025R01 - NRC Website

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"l-FR[ the main _ steam lines were not isolated following main steam line high temperature log,

! ic 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. There o

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3*2.A P.e p e e : Unsier '"e d.nical Spe,:tf! cation,

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Date,f 0;currar.cc _ 9/26/79

'i';;r.e of Occurrence 1525 Unit 1

Identif:c3* ion and De scription <>f Occurrence:

Due to variation in interpretation of technical specification the main steam lines were not isolated within eight hours as req.iired kv Technical Specification Table 3.2.A.

Conditions Prior to Occurrence:

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U-3 0 0% refueling outage A: tiun s;v cifieu in the Technical Sp;cificHica Surveinance Requirer.:en's met

<lu" 'o sr..mer.ible,e_qu.y.myn: _Dere t ibe.

MSIV's not closed within eight hours.

At> tem n Caur. c,f Occut re nce A half isolation signal was received from the "D" logic d'u'e toan ' apparentl'y fauTtf temperature switch.

A JIWR was reviewed by PORC and placed

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on main steam line "D" logic to clear the isolation signal and allow safe personnel entry.

While troubleshooting the logic problent the "A" logic rain steam high temperature circuit fuse opened due to an open cable.

During the event, no violation of the technical specification was recognized.

Af ter review of the event the next day, it was determined that the main steam lines should have been isolated by 2325 hours0.0269 days <br />0.646 hours <br />0.00384 weeks <br />8.846625e-4 months <br />.

The reactor was shut down at 1859 hours0.0215 days <br />0.516 hours <br />0.00307 weeks <br />7.073495e-4 months <br /> on 9/26/79, and main steam lines were isolated at 0114 hours0.00132 days <br />0.0317 hours <br />1.884921e-4 weeks <br />4.3377e-5 months <br /> on 9/27/79 Analysis of Occurrence There was no damage to plant equipment, no activity released, no personnel exposure or injury, and no ha::ard to health or safety of the public.

Full automatic isolation capabi Corr <:c:lity s*.111 existed.

ve Ac: ton: The fuse was replaced on the "A" line returning it to service; and an investigation on the "D" line revealed that cable 1FC143II3 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 i'nterpre-tation of this particular technical specification has been discussed with plant management through PORC.

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