ML20010F561

LER 81-006/03L-0:on 810803,during Routine Calibr Check of Pressurizer Level Instrumentation,One Channel Found Outside Tech Spec Range.Caused by Zero Drift of Level Transmitter Calibr.Instrument Adjusted.New Calibr Procedure Formalized

ML20010F561
Person / Time
Site:	Point Beach
Issue date:	08/20/1981
From:	Fay C WISCONSIN ELECTRIC POWER CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML20010F559	List: ML20010F558 ML20010F561
References
LER-81-006-03L, LER-81-6-3L, NUDOCS 8109100352
Download: ML20010F561 (2)

Text

NRC F ORM 366 U. S. NUCLE AR REGULATORY COMMISSIOM (7-7 7)

LICENSEE EVENT REPORT

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7 8 60 61 DOCKET NUMBER SR 69 EVENT DATE 7* 75 REPORT DATE 80 EVENT DESCRIPTION AND Pr '.3ABLE CONSEQUENCES h l 0 l 2 l l During a routine calibration check of pressurizer level ins t rumen tation ,l

[O;3l lit was found that one of three channels had drifted beyond the range l l O 14 l l allowed by the Technical Specifications. With the failure of one other l l O l 3 l l ins trumen t, this situation would have caused a pressurizer high level l l O [s j l trip at 96.42% vice 95% as required. This event is reportable in l

[ O l 7 l l accordance with Technical Specification 15.6. 9. 2.B. l . l 101811 I 7 8 9 80 SYSTEM CAUSE CAUSE COMP. VALVE CODt CODE SU8 CODE COMPONENT CODE SUSCODE SUSCODE lo19l l I l El@ W@ (_Gj @ lI l N l Sl Tl Rl Ul@ Wh l_Z_j @

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44 47 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS h l i l o l l The event was attributed to zero drift of the level transmitter l li li i [ calibration. The instrument was adiusted and returned to service. A I

, 7 l new calibration procedure is being formalized that will aid in l l , l 3 [ [ preventing recurrence of a large zero drift in the pressurizer level I i3 g4i l instruments. l 7 8 9 80 ST S  % POWER OTHER STATUS DISCOV RY DISCOVERY DESCRIPTION i s (_Ej@ l 1 l 0 l 0 l@l N/A l J@l Periodic calibration check l ACTIVITY CO TENT nEtE ASED Oe RELE ASE AMOUNT OF ACTIVITY LOCATION OF RELE ASE I1 l6'l [_Zj @ l Zl@l N/A l l N/A l 7 8 9 10 11 44 45 83 PERSONNEL EXPOSURES NUMB 2P TYPE DESCRIPTION l t l 7 l l 010 l 0 l@(_Z_j@l N/A +

l PERSONNE L INJURIES NUMBER DESCRIPTION 7

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LOSS OF OR DAMAGE TO Ft CILITY TYPE DESCRIPTION 9

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ISSUEN/A@ DESCRIPTION OCK 05000301Q 2 0 l S PDR l

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NAME OF PREPARER C* N' OY PHONE: 414/277-2811 {

j-ATTACHMENT TO LICENSEE EVENT REPORT NO. 81-006/03L-0 Wisconsin Electric Power Company Point Beach Nuclear Plant Unit 2 Docket No. 50-301 i.

During a routine check of pressurizer Juvel instru-ments on August 3, 1981, it was found that the zero setpoint of all three instruments had drif ted low. Two of the channels remained within the range allowed by the Technical Specification, but the channel associated with LT-428 had drifted beyond the required limit. This drift is nonconservative with respect to the Technical Specification, which requires the trip signal to be initiated at 95%. The actual setpoint is set conservatively at 90%. The total drift of 6.42% low would have caused the instrument to give an input to the reactor trip circuitry at an actual level of 96.42%. The reactor trip affected is caused by two of three of the instruments exceeding the high level setpoint.

Normal calibration of the level transmitter is done while in cold shutdown and checked while at power by channel comparison checks and correlation with indication of the cold calibration channel. . Zero drif t of the cold calibration channel can be checkeF. at power. The out-of-specification condition was corrected using a calibration procedure which adjusts the zero point of the transmitter based on these comparison checks and cold channel drift. Future occurrences will be prevented by formalizing the zero-point calibration procedure and periodically checking instruments ior early indication of calibration drift.

This event is reportable in accordance with Technical Specification 15.6. 9.2.B.1 as a 30-day report. The resident inspector was informed and similar channels in Unit 1 were checked for indications of transmitter zero calibration drif t.