ML050190200

Special Report of Inoperability of Main Steam Line Gross Gamma Activity Monitor

ML050190200
Person / Time
Site:	Palisades
Issue date:	01/10/2005
From:	Domonique Malone Nuclear Management Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
RIA-2323
Download: ML050190200 (2)

Text

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Co7f)led to arEx Palisades Nuclear Plant COperated by Nuclear Management Company, LLC January 10, 2005 U S Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Palisades Nuclear Plant Docket 50-255 License No. DPR-20 Special Report Of Inoperability Of Main Steam Line Gross Gamma Activity Monitor The Palisades Plant Offsite Dose Calculation Manual, Appendix A, Table A-1, Action 4, requires that a special report be submitted to the Nuclear Regulatory Commission within 30 days for the inoperability of RIA-2323, Main Steam Safety and Dump Valve Discharge Line Gross Gamma Activity Monitor, when the instrument is not restored to operable status within 7 days. The enclosed report summarizes the actions taken, the cause of the inoperability, and the plans and schedule for restoring the instrument to operable status.

Summary of Commitments This letter contains no new commitments and no revisions to existing commitments.

Daniel J alone Site Vice President, Palisades Nuclear Plant Nuclear Management Company, LLC Enclosure CC Administrator, Region l1l, USNRC Project Manager, Palisades USNRC Resident Inspector, Palisades USNRC 27780 Blue Star Memorial Highway . Covert, Michigan 49043-9530 gL Telephone: 269.764.2000

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ENCLOSURE SPECIAL REPORT OF INOPERABILITY OF RIA-2323 MAIN STEAM LINE GROSS GAMMA ACTIVITY MONITOR BACKGROUND On December 13, 2004, RIA-2323, Main Steam Safety and Dump Valve Discharge Line Gross Gamma Activity Monitor, was declared inoperable after observation of a downscale failure on the instrument's display.

ACTIONS TAKEN A recent similar occurrence was experienced with RIA-2323 in November 2004.

Corrective actions in response to that occurrence included replacing the radiation detector and re-adjusting the discriminator setting. RIA-2323 was then declared operable.

In response to the recurrence on December 13, 2004, additional troubleshooting is in progress. This troubleshooting includes placing RIA-2323 back in service for further monitoring. RIA-2323 remains inoperable during this monitoring period.

The preplanned alternate method of monitoring is in place as a compensatory measure.

CAUSE OF INSTRUMENT INOPERABILITY The cause of the problem with RIA-2323 has not been definitively identified. There appears to be an intermittent problem with RIA-2323 as it self-restores shortly after exhibiting the problem, and then appears to function normally for extended periods of time.

PLANS AND SCHEDULE FOR RESTORING INSTRUMENT OPERABILITY Monitoring and troubleshooting will continue with RIA-2323 being restored to operable not later than June 1, 2005.

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