ML072180358
| ML072180358 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 07/13/2007 |
| From: | Schimmel M Constellation Energy Group |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| Download: ML072180358 (2) | |
Text
Mark A. Schimmel Plant General Manager P.O. Box 63 Lycoming, New York 13093 315.349.5205 315.349.1321 Fax Constellation Energy$
Nine Mile Point Nuclear Station July 13, 2007 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001
SUBJECT:
Nine Mile Point Nuclear Station Unit No. 1; Docket No. 50-220 Special Report: Channel #12 of the Suppression Chamber Water Level Accident Monitoring Instrumentation Inoperable During Planned Maintenance In accordance with Action 4.a of Nine Mile Point Unit 1 (NMP1) Technical Specification (TS) Table 3.6.11-1, "Accident Monitoring Instrumentation,"
and Table 3.6.11-2, "Accident Monitoring Instrumentation Action Statements," 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.
Description of Event On July 10, 2007, at 1019 hours0.0118 days <br />0.283 hours <br />0.00168 weeks <br />3.877295e-4 months <br />, operators declared Channel #12 of the Suppression Chamber Water Level Accident Monitoring instrumentation (Level Indicator LI 58-05A) inoperable in support of pre-planned troubleshooting activities on Suppression Chamber Level Switch LSE-58-05B. Activities were directed at clearing an invalid high water alarm signal in the Control Room. The invalid alarm signal was thought to be originating from the LSE-58-05B electronic alarm unit.
Operators verified Suppression Chamber water level to be normal at 10.8 feet.
Cause of Inoperabiitv Troubleshooting activities on Suppression Chamber Water Level Switch LSE-58-05B determined the instrument high water level setpoint to be out of calibration resulting in the invalid alarm actuation.
Document Control Desk July 13, 2007 Page 2 Actions Taken Technicians completed calibration of Suppression Chamber Water Level Switch LSE-58-05B. Alarm indications were cleared in the Control Room. Operators returned Channel #12 Suppression Chamber Water Level Indicator LI 58-05A to an operable status on July 10, 2007 at 1054 hours0.0122 days <br />0.293 hours <br />0.00174 weeks <br />4.01047e-4 months <br />.
Should you have any questions regarding the contents of this letter, please contact T. F. Syrell, Licensing Director, at (315) 349-5219.
Very truly yours, MAS/GB/
cc:
S. J. Collins, NRC Regional Administrator, Region I L. M. Cline, NRC Senior Resident Inspector M. J. David, NRC Project Manager
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