ML20056H333

Special Rept:On 930812-30,differential Air Temp Instrumentation Inoperable.Caused by Problem W/Power Supply Panel 0EM01J.Replacement Power Supply Unavailable. Engineering Change Request ECN 28103 Processed

ML20056H333
Person / Time
Site:	Clinton
Issue date:	08/30/1993
From:	Phares R ILLINOIS POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
U-602181, NUDOCS 9309090163
Download: ML20056H333 (3)

Text

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Ilknois Power Company Chnton Power Station I P.O. Box 678 i l Chntan. IL 61727 i

ILLIN91S TEiii "

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• SE.iO0c August 30,1993 Docket No. 50-461 10CFR50.36 Document Control Desk Nuclear Regulatory Commission Washington, D.C. 20555

Subject:

Special Report: Inoperability of the Differentia! Air Temperature Instmmentation on the hieteorological Tower at Clinton Power Station (CPS) i

Dear Sir:

j Clinton Power Station (CPS) Technical Specification 3.3.7.3, Action "a," requires inoperabilities of meteorological monitoring instrumentation channels for more than 7 days [

be reponed to the Nuclear Regulatory Commission (NRC) within the next 10 days pursuant to Specification 6.9.2, SPECIAL REPORTS. The difTerential air temperature  :

instmmentation was declared inoperable from 0907 hours0.0105 days <br />0.252 hours <br />0.0015 weeks <br />3.451135e-4 months <br /> on August 12,1993 until 1305 l hours on August 30, 1993. This Special Report is therefore being submitted -in [

accordance with the CPS Technical Specifications to p mide information regarding the ,

cause of the malfunction and action that was taken to restore the instrumentation to 1 OPERABLE status.

Cause of hfalfunction / Corrective Actions  !

On August 12,1993, while performing the daily channel check in accordance with Technical Specification Surveillance Requirement 4.3.7.3, Radiation Protection personnel noted that the differential air temperature indication did not agree with the differential l

temperature obtained by subtracting the 10-meter temperature indication from the 60-meter temperature indication. A maintenance work request (No. D52136) was initiated, ,

and at 0907 hours0.0105 days <br />0.252 hours <br />0.0015 weeks <br />3.451135e-4 months <br />, the differential air temperature instrumentation was declared inoperable.

i Control and Instrumentation (C&I) personnel began troubleshooting on August >

l 13,1993 in accordance with maintenance work request (hfWR) D52136. On August 16,

! 1993 they determined that the differential air temperature instrumentation had ,

malfunctioned because of a problem with the power supply in panel OEh10lJ. The readings for this power supply are normally 15 volts /-5 volts but were found to be reading 14 volts /-4.7 volts. A temporary substitute power supply for troubleshooting purposes was installed to verify that the original power supply was not functioning properly. It was noted that the temperature instrumentation read correctly with the substitute power supply 9309090163 930830 PDR ADOCK 05000461  ?'I 0-S PDR  ?[LJ '

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• Page 2 of 2 to U-602181 l -in place. A replacement power supply was therefore requested from stores, and the I

original power supply was temporarily reinstalled in the system. IP attributes the failure to a recent nearby lightning strike which could have degraded.the meteorological tower circuitry.

Upon investigation, it was determined that a spare power supply was not in stock and had been on order with the vendor for several months. After discussing the delays with the vendor, it was discovered that the order had not been filled because the original manufacturer was no longer in business. An attempt was made to see whether the vendor had any more of this particular discontinued power supply in stock, but they did not. No other manufacturers make a power supply configured exactly like the current power

, supply in use at CPS. An Engineering Change (ECN 28103) for a new multipurpose l power supply model (Sola Model Number 85-15-33115) was processed in order to adapt

( the new power supply to the same power supply parameters as the previous model.

i Initiation of the Engineering Change, evaluation of the associated 10CFR50.59 safety screening, procurement of a new type power supply, and the occurrence of foul weather delayed repairs for several days. The new power supply was installed on August 23,1993 l and a channel calibration (per CPS Procedure 9437.14) was successfully performed for the meteorological system on August 28,1993. The Post-Maintenance testing was completed and the differential air temperature instrumentation was declared OPERABLE at 1305 hours0.0151 days <br />0.363 hours <br />0.00216 weeks <br />4.965525e-4 months <br /> on August 30,1993.

Submittal of this letter satisfies the requirements of CPS Technical Specifications 3.3.7.3, Action "a," and 6.9.2 for submitting a Special Report for meteorological tower inoperablities.

Sincerely yours, hr Richard F. Phares Director-Licensing CLJE/nis cc: NRC Clinton Licensing Project Manager NRC Resident Office, V-690 Regional Administrator, Region III, USNRC Illinois Department ofNuclear Safety

SUBJECT:

Special Report: Inoperability of the Differential Air U-602181 Temperature Instrumenation on the Meteorological L47-93(08-30)LP Tower at Clinton Power Station (CPS) 8E.100c 1

bec J. S. Perry, V-275 ,

J. G. Cook, T-31 A J. A. Miller, V-928C P. D. Yocum, T-31 A l W. M. Clark, T-31 A T. I. Leflier, V-928 T. B. Elwood, V-920 NRAG Secretary, V-780 S. A. Zabel, Schiff, Hardin, & Waite S. Parr, Soyland C. L. Jones-Endres. V-920 Author (s)

Technical Validttor

1. M. R. Page.l. T-31G

• Associated Cerrective Action Document CR-1-93-08-025 1

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