ML20085C893

AO 50-254/74-36:on 741105,two Main Steam Line High Flow Switches Exceeded Tech Spec Limits.Caused by Instrument Drift.Switches Recalibr

ML20085C893
Person / Time
Site:	Quad Cities
Issue date:	11/15/1974
From:	Kalivianakis N COMMONWEALTH EDISON CO.
To:	Oleary J US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20085C894	List: ML20085C893 ML20085C905
References
AO-50-254-74-36, NJK-74-386, NUDOCS 8307130190
Download: ML20085C893 (3)

Text

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Mr. John F. O' Leary, Director -

Di re c to ra te of Licensing Regulation  !

4 U. S. Atonic Energy Commission ~

Washington, D. C. 20545

REFERENCE:

Quad-Citics Nuclear Power Station i Docket No. 50-254, DPR-29 Appendix A, Sections 3.2.A, Tah i c- 3.2.1, and 6.6.B.1.a

Dear Mr. O' Leary:

, Euclosed please find Abnormal Occurrence Report No. A0 50-254/74-36 f or Quad-Citics Nucica r Power S ta tion. This occurrence was pre-

. viously reported to Region III, Directorate of Regulatory Operations by telephone on Novenber 6, 19 74 and to you and Region III, Dir-I cctorate of Regulatory Operations by telecopy on November 6, 1974.

This report is subnitted to you in accordance with the requirements '

of Technical Spenification 6.6.B.l.a.

Very truly yours, COMMONUE ALT!! EDISON COMP ANY

, QUAD-CITIES NUCLEAR PONER STATION i ,d(lfA . U' N. J. Kalivianakis Station Superintendent NJK/RAR/lk 1

. cc: Region III, Directorate of Regulatory Operations S. Abel

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e 8307130190 741115 PDR ADOCK 05000254 oor S PDR 410

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, . Q REPORT NUMllER: A0-50-254/74-36 REPORT DATE: November 15, 1974 OCCURRENCE DATE: November 5, 1974 FACILITY: Quad-Citics Nuc1 car Power Station Cordova, Ill. 61242 IDENTIFICATION OF OCCURRENCE:

Two !!ain Stcan Line High Flou switches exceeded their Technical Specification trip setting limit.

CONDITIONS PRIOR TO OCCURRENCE:

Unit One was in the run raod e at about 700 MWe and lucreasing load at 10 MWe per hour.

DESCRIPTION OF OCCURRENCE:

On Novenbcr 5, 1974 at 1300 hours0.015 days <br />0.361 hours <br />0.00215 weeks <br />4.9465e-4 months <br /> while doing routine surveillance calibration of the main stean line high flow switches, two of then were found to trip at values exceeding the Technical Speci-fication Limiting Condition f or Ope ration. Section 3.2.A Tabic 3.2.1 of the Technical Specifications gives this condition as

< 120 percent of rated secan flow corresponding to < 109 PSID.

Flow suitches, FS-1-2 61-2 A an d FS-1-2 61-21; tripped at 111 and 112 PSID respectively. No operator actions were required to bring the situation under control.

DESIGNATION OF APPARENT CAUSE OF OCCURRENCE:

Other-Instrument Drift The instrunent histories for the two flow switches were reviewed and no trends could be identified that would imply any node of failures other than instrument drift.

ANALYSIS OF OCCUP.RENCE:

FS-1-261-2A is on the "A" stcan line and FS-1-261-2K is on the "C" stean line. If a high s tenn flou condition had occurred in the "A" line the corresponding flow switch would not have tripped until the flow reached 121.1 percent. Sinilarly, on the "C" line the switch would not have tripped until the flow rea ched 121.6 pe rcen t. In both cases, houever, the th re e other switches nonitoring the flow in cach steam line would have tripped before the 120 percent limit was reached and the net result would have been a primary containnent isolation. All other Main Steam Line liigh Flow switches were found to trip at a value 1 css than 109 psid. Therefore, no adverse consequencas from the standpoint of reactor safety existed. Public health and safety were in no way jeopardized as a'rcsult of this occurrence.

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. A0-50-254/74-36 -2. November 15, 1974

, CORRECTIVE ACTIOQ:

The switches were recalib rated and functionally tested in accord-ance with the instrunent surveillance test procedures. The quarterly insstument calibration results were plotted and the data evaluated. Additional corrective action is described below in the Failure Data Section.

FAILURE DATA:

Equipment Identification EPN: FS-1-261-2A & K Manfacturer: Barton Model 278 Range 0-200 PSID There have been numerous cases of minor set point drift with these switches over the past several years.

Since the setpoint for the switches is set within only 2 PSID of the Technical Specification limit, small drifts have caused the Limiting Condition for Operation to be exceeded. As a step to correct this, the following action will be taken.

As additional corrective action to prevent further violations of this type, the set point for all steam line flow switches will be adjusted to 105 PSID. This action will allow adequate margin from the normal operating conditions and provide added conservatisn from the Technical Specification Limiting Condition.

This will allow for minor instrument drift in both directions and still maintain the safety measures required.

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