ML100550484

Special Report: Inoperable Suppression Chamber Water Level Instrumentation

ML100550484
Person / Time
Site:	Nine Mile Point
Issue date:	02/15/2010
From:	Lynch T Constellation Energy Group, EDF Group, Nine Mile Point
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
Download: ML100550484 (2)

Text

Thomas A. Lynch P.O. Box 63 Plant General Manager Lycoming, New York 13093 CENG a joint venture of Consteillation :

Energy" eDF NINE MILE POINT NUCLEAR STATION February 15, 2010 U. S. Nuclear Regulatory Commission Washington, DC 20555-0001 ATTENTION: Document Control Desk

SUBJECT:

Nine Mile Point Nuclear Station Unit No. 1; Docket No. 50-220 Special Report: Inoperable Suppression Chamber Water Level Instrumentation In accordance with Action 4.a of Nine Mile Point Unit 1 (NMPI) Technical Specifications (TS) Table 3.6.11-2, "Accident Monitoring Instrumentation Action Statements," and TS Section 6.6.6.h, "Special Reports," Nine Mile Point Nuclear Station, LLC (NMPNS) is submitting the following Special Report concerning inoperability of Channel #12 of the Suppression Chamber Water Level Accident Monitoring Instrumentation.

Descriptionof Event On February 1, 2010, at 0940 hours0.0109 days <br />0.261 hours <br />0.00155 weeks <br />3.5767e-4 months <br />, operators noted that Channel #12 of the Suppression Chamber Water Level Accident Monitoring Instrumentation had gone downscale while plant process computer maintenance was being performed. At 0941 hours0.0109 days <br />0.261 hours <br />0.00156 weeks <br />3.580505e-4 months <br />, Channel #12 of the Suppression Chamber Water Level Accident Monitoring Instrumentation was declared inoperable.

Cause of Inoperabiitv The cause of the instrumentation going downscale was found to be the removal of a computer interface card during the scheduled plant process computer maintenance. This caused a break in the current loop and a loss of the control room indication for Channel #12 of the Suppression Chamber Water Level Accident Monitoring Instrumentation.

Document Control Desk February 15, 2010 Page 2 Action Taken At 0945 hours0.0109 days <br />0.263 hours <br />0.00156 weeks <br />3.595725e-4 months <br /> on February 1, 2010, a computer interface card that had been previously removed as part of maintenance was reinstalled. This restored the current loop to the instrument and the instrument indication returned to normal. Channel #12 of the Suppression Chamber Water Level Accident Monitoring Instrumentation was declared to be operable at 0945 hours0.0109 days <br />0.263 hours <br />0.00156 weeks <br />3.595725e-4 months <br />. The total time that Channel #12 of the Suppression Chamber Water Level Accident Monitoring Instrumentation was inoperable was approximately four minutes.

Should you have any questions regarding the information in this submittal, please contact T. F. Syrell, Licensing Director at (315) 349-5219.

Very truly yours, TAL/MHS cc: NRC Regional Administrator, Region I NRC Senior Resident Inspector NRC Project Manager