05000311/LER-1981-119, Forwards LER 81-119/03L-0.Detailed Event Analysis Encl

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Forwards LER 81-119/03L-0.Detailed Event Analysis Encl
ML20039B621
Person / Time
Site: Salem 
Issue date: 12/10/1981
From: Midura H
Public Service Enterprise Group
To: Haynes R
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML20039B622 List:
References
NUDOCS 8112230314
Download: ML20039B621 (4)
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LER-1981-119, Forwards LER 81-119/03L-0.Detailed Event Analysis Encl
Event date:
Report date:
3111981119R00 - NRC Website
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Pubhc Service Electric ana Gas Company P.O. Box #168 Hancocks Bridge. New Jersey 08038 i

December 10, 1981 i

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l Mr.

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Haynes Director of USNRC cf Office of Inspecticn and Enforcement G

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Region 1

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631 Park Avenue 8

King of Prussia, Pennsylvan!.d 19406 MEUD

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DEC 2 21981> [

Dear Mr. Haynes:

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""Tf"".;,'9 LICENSE NO. DPR-75 offx DOCKET NO. 50-311

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7 REPORTABLE OCCURRENCE 81-119/03L

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, T tp Pursuant to the requirements of Salem Generating Station Unit No. 2, Technical Specifications, Section 6.9.1.9.b, we are submitting Licensee Event Report for Reportable Occurrence 81-119/03L.

This report is required within thirty (30) days of the occurrence.

Sincerely yours,

,/l(,N Y&'d H.

J. Midura General Manager -

Salem Operations CC:

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Report Number:

81-119/03L i

Report Date:

12-10-81 Occurrence Date:

11-11-81, 11-17-81, 11-18~81, and 11-22-81 Facility:

Salem Generating Station, Unit 2 Public Service Electric & Gas Company 3ancocks Bridge, New Jersey 08038 IDENTIFICATION OF OCCURRENCE:

Nuclear Instrumentation - Power Range Channel N Inoperable.

This report was initiated by Incident Reports81-457,81-463,81-464, 81-465, and 81-475.

CONDITIONS PRIOR TO OCCURRENCE:

11-11-81 Mode 1 - Rx Power 100% - Unit Load 1150 MWe 11-17-81 Mode 1 - Rx Power 50% - Unit Load 540 MWe 13-17-81 Mode 1 - Rx Power 94% - Unit Load 1100 MWe 11-18-81 Mode 1 - Rx Power 86% - UI.it Load 1000 MWe 11-22-81 Mode 1 - Rx Power 50% - Unit Load 580 MWe l

DESCRIPTION OF OCCURRENCE, APPARENT CAUSE, AND CORRECTIVE ACTION:

l Fro u November 11, 1981 through November 28, 1981 malfunctions in Power Range Channel N-4^ Nuclear Instrumentation caused a series of related incidents.

On November 11, 1SCl, after a Quadrant Power Tilt Ratio (QPTR) calculation, it was determined that the QPTR was 1.03.

Channel N-43 was low by 3%.

At 1430 hours0.0166 days <br />0.397 hours <br />0.00236 weeks <br />5.44115e-4 months <br /> Action Statement 3.2.4.a was entered, and, accordingly, reactor power was reduced to 90%.

In order'to correct Channel N-43, the summing amplifier was recalibrated and tested satisfactorily.

The QPTR was recalcu-lated satisfactorily, and at 0825 hours0.00955 days <br />0.229 hours <br />0.00136 weeks <br />3.139125e-4 months <br />, November 12, 1981 Action Statenznt 3.2.4.a was terminated.

On Novenber 17, 1981, after reaching 50% reactor power, following a startup from a tri.p the previous day, the QPTR was again calculated.

Again it was datermined to be 1.03.

At 0230 hours0.00266 days <br />0.0639 hours <br />3.80291e-4 weeks <br />8.7515e-5 months <br /> j

Action Statement 3.2.4.a was entered, and reactor power was held at 50%.

After holding the reactor power constant for one hour, the QPTR was recalculated and found to be within specification at 1.02.

At 0338 hours0.00391 days <br />0.0939 hours <br />5.588624e-4 weeks <br />1.28609e-4 months <br /> Action Statement 3.2.4.a was terminated.

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LER 81-119/03L Later in the day a QPTR Surveillance calculation determined QPTR was cut of specification at 1.03.

At 1250 hours0.0145 days <br />0.347 hours <br />0.00207 weeks <br />4.75625e-4 months <br />,

' November 17, 1981 Action Statement 3.2.4.a was entered.

Flux mapping was performed, and established the QPTR as satisfactory.

Since N-43 was the channel whi.ch caused the QPTR to be out of specificauion, due to full power current drift it was declared inoperable at 1030 hours0.0119 days <br />0.286 hours <br />0.0017 weeks <br />3.91915e-4 months <br />, November 18, 1981,'and Action Statement 3.3.1 Action 2 was entered.

All associated bistables were placed in the tripped condition within one hour.

A QPTR calculation was then performed utilizing the three remaining operable channels.

The results were satisfactory and at 1115 hours0.0129 days <br />0.31 hours <br />0.00184 weeks <br />4.242575e-4 months <br />, November 18, 1981 Action Statement 3.2.4.a was terminated.

A plateau calibration was performed on Channel N-43.

The channel was then recalibrated utilizing new full power currents.

QPTR cali' orations were performed at least once every 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />, as required by Technical Specifications.

At 2230 hours0.0258 days <br />0.619 hours <br />0.00369 weeks <br />8.48515e-4 months <br />, November 18, 1981, Channel N-43 was tested satisfactorily and declared operable, and Action Statement 3.3.1 Action 2 was terminated.

The instrument manufacturer was contacted con 7erning the problems being experienced.

They indicated that another plant with similar instrumentation was experiencing similar problems which had been diagnosed as premature detector aging.

Their recommendation was to change the detector if problems continued to occur.

At 2320 hours0.0269 days <br />0.644 hours <br />0.00384 weeks <br />8.8276e-4 months <br />, November 22, 1981, Power Range Channel N-43 was declared inoperable due to current drift, indicating detector degradation, and Action Statement 3.3.1 Action 2 was entered.

The associated bistables were placed in the tripped condition as required by Technical Specifications.

All requirements of Technical Specification 3.3.1 Action 2 were met.

On November 24, 1981 the reactor tripped.

While the unit was shutdown, according to the manufacturerb recommendation, the upper and lower detectors of Channel N-43 were replaced and recalibrated.

The channel was tested satisfactorily and declared operable.

At 0327 hours0.00378 days <br />0.0908 hours <br />5.406746e-4 weeks <br />1.244235e-4 months <br />, November 28, 1981 Acticn Statement 3.3.1 Action 2 was terminated.

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LER 81-119/03L -

ANALYSIS OF OCCURRENCE:

Technical Specification 3.2.4.a requires:

With the Quadrant-Power Tilt Ratio (QPTR) determined to exceed 1.02 but-less than or equal to 1.09, calculate the QPTR'at least once per hour until either the QPTR is re-duced to within its limit, or thermal power is reduced to less than 50% of rated thermal power.

Within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> either reduce the QPTR to within its limit, or reduce thermal power at least 3% from rated thermal power for each 1% of indicated QPTR in-excess of 1.0.

Technical Specification 3.3.1 Acon 2 requires:

With the number of operable channels one less than the total number of channels, atartup and/or power operation may proceed provided the following conditions are satisfied:

a) the operable channel is placed in the tripped condition within one hour; d) the Quadrant Power Tilt Ratio is verified at least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> when thermal power is greater than 75% of rated thermal power.

FAILURC DATA:

Westinghouse Electric Corporation Power Range Detector i

Prepared By F.

Dickey

, kl[' c wd Gen (ral Manager -

Salem Operations SORC Meeting No.81-125 4

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J J

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