ML020580195

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Special Report, Channel #12 Suppression Chamber Water Level Indicator Inoperable
ML020580195
Person / Time
Site: Nine Mile Point Constellation icon.png
Issue date: 02/08/2002
From: Montgomery B
Constellation Nuclear
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
NMP1L 1641
Download: ML020580195 (2)


Text

P.O. Box 63 Lycoming, New York 13093 Constellation Nuclear Nine Mile Point Nuclear Station February 8, 2002 A Member of the NMP1L 1641 Constellation Energy Group U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555 RE: Nine Mile Point Unit 1 Docket No. 50-220 DPR-63

Subject:

Special Report, Channel #12 Suppression Chamber Water Level IndicatorInoperable Gentlemen:

In accordance with Action Statement 4.a of Nine Mile Point Unit 1 Technical Specification Table 3.6.11-2, Accident Monitoring Instrumentation Action Statements, Nine Mile Point Nuclear Station, LLC is submitting the following Special Report concerning the inoperability of Channel #12 Suppression Chamber Water Level indicator.

Description of Event On January 25, 2002 at 0930 hours0.0108 days <br />0.258 hours <br />0.00154 weeks <br />3.53865e-4 months <br /> the operating crew declared the Channel #12 Suppression Chamber Water Level indicator inoperable after noting that the water level indicator was erratic and not trending as expected. The operating crew verified that the Channel #11 Suppression Chamber Water Level indicator was operable.

Cause ofEvent The cause of the Channel #12 Suppression Chamber Water Level indicator degraded response is ripple voltage on the output of the AC to DC power supply to the indicator. The power supply, PWRS-(1S12)24VDC, is a Bailey Type 765. The ripple voltage is attributed to the aging of the capacitors associated with the power supply.

I/V

Page 2 NMP1L 1641 A search of work history did not identify any previous failures of power supply PWRS-(iS12)24VDC.

CorrectiveActions

1. Power supply, PWRS-(lS12)24VDC, will be repaired by March 28, 2002.
2. A Preventive Maintenance activity was established to routinely replace capacitors on power supply PWRS-(lS12)24VDC.

Very truly yours, ce.Montg cry Gene al Manager Nuclear Engineering LAH/KLE/cld cc: Mr. H. J. Miller, NRC Regional Administrator, Region I Mr. G. K. Hunegs, NRC Senior Resident Inspector Records Management