ML052240250

Special Report, Channel #12 of the Containment Hydrogen Monitoring System Inoperable

ML052240250
Person / Time
Site:	Nine Mile Point
Issue date:	08/03/2005
From:	Godley R Constellation Energy Group
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
NMP1L 1970
Download: ML052240250 (2)

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Constellation Energy P.O. Box 63 Lycoming, New York 13093 Nine Mile Point Nuclear Station August 3, 2005 NMP1L 1970 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555-0001

SUBJECT:

Nine Mile Point Unit 1 Docket No. 50-220 Facility Operating License No. DPR-63 Special Report, Channel #12 of the Containment Hydrogen Monitoring System Inoperable Gentlemen:

In accordance with Action 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 inoperability of Channel #12 of the Containment Hydrogen Monitoring (CHM) System.

Description of'Event On July 20, 2005, at approximately 08:01 hours, operators removed Channel #12 of the CHM System from service to perform surveillance testing. During the performance of the surveillance testing, the Channel #12 alarm functions for high hydrogen and high oxygen concentrations were found inoperable.

The redundant Channel #11 of the CHM System was verified to be operable prior to removal of Channel #12 from service.

Cause ofInoperabilitt Channel #12 of the CHM System was removed from service to perform Technical Specification required surveillance testing. During the performance of the surveillance testing, the alarms for high hydrogen and oxygen concentrations in the control room failed to annunciate. A failed time delay relay was determined to be the cause.

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Page 2 NMP1L 1970 Actions Taken The relay was replaced and post maintenance testing was completed satisfactorily. Channel #12 of the CHM System was restored to-operable status on July 20, 2005, at approximately 21:01 hours.

Very truly yours, Robert C. Godley Manager Operations RCG/RF/sac Attachment cc: Mr. S. J. Collins, NRC Regional Administrator, Region I Mr. G. K. Hunegs, NRC Senior Resident Inspector