ML021070521

Special Report, Channel #11 Containment Hydrogen Monitoring System Inoperable for Unscheduled Corrective Maintenance

ML021070521
Person / Time
Site:	Nine Mile Point
Issue date:	04/03/2002
From:	Hopkins L Constellation Nuclear
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
NMPIL 1657
Download: ML021070521 (2)

Text

P.O. Box 63 Lycoming, New York 13093 Constellation Nuclear Nine Mile Point April 3, 2002 Nuclear Station NMP1L 1657 A Member of the Constellation Energy Group U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555 RE: Nine Mile Point Unit I Docket No. 50-220 DPR-63

Subject:

Special Report, Channel #11 ContainmentHydrogen MonitoringSystem Inoperablefor Unscheduled Corrective Maintenance Gentlemen:

Nine Mile Point Nuclear Station, LLC is submitting the following Special Report for Nine Mile Point Unit 1 (NMP1) concerning the inoperability of Channel #11 Containment Hydrogen Monitoring System (CHMS). This submittal is in accordance with Action Statement 4.a of Table 3.6.11-2, "Accident Monitoring Instrumentation Action Statements," of the NMP1 Technical Specifications.

Descriptionof Event On March 21, 2002, at approximately 0820 hours0.00949 days <br />0.228 hours <br />0.00136 weeks <br />3.1201e-4 months <br />, operators declared Channel #11 CHMS inoperable in order to perform unscheduled corrective maintenance on the drywell Containment Airborne Activity Monitoring (CAM) system. The maintenance consisted of replacing a photohelic flow indicator that had failed due to moisture intrusion. The isolation boundary for the CAM system maintenance required the shared Channel #11 Hydrogen-Oxygen sample stream return line isolation valves (primary containment isolation valves) to be closed, thereby causing Channel #11 CHMS to be inoperable. The corrective maintenance was completed and the Channel #11 CHMS returned to service at approximately 2005 hours0.0232 days <br />0.557 hours <br />0.00332 weeks <br />7.629025e-4 months <br /> on March 22, 2002.

The redundant Channel #12 CHMS was verified in service prior to removing Channel

1. 11 from service.

Page 2 NMPIL 1657 Cause of Event The Channel #11 CHMS was declared inoperable in order to perform unscheduled corrective maintenance on the interfacing CAM system.

CorrectiveActions The maintenance was completed and Channel #11 CHMS was returned to operable status. The duration of inoperability was approximately 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />.

Very truly yours, Lawrence A. Hopkins Unit I Plant General Manager LAHIIAA /jm cc: Mr. H. J. Miller, NRC Regional Administrator, Region I Mr. G. K. Hunegs, NRC Senior Resident Inspector Records Management