05000333/LER-1979-069-03, /03L-0:on 790908,recurrent Failure of Rod Block Monitor B Began.Caused by Failure of Low Power Range Monitor Loose Switch Connector & Sticky Contacts in Rod Info Relays. Replacement of Relay Card Eliminated Failures

/03L-0:on 790908,recurrent Failure of Rod Block Monitor B Began.Caused by Failure of Low Power Range Monitor Loose Switch Connector & Sticky Contacts in Rod Info Relays. Replacement of Relay Card Eliminated Failures

ML19209B719
Person / Time
Site:	FitzPatrick
Issue date:	10/05/1979
From:	W. Verne Childs POWER AUTHORITY OF THE STATE OF NEW YORK (NEW YORK
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML19209B713	List: 05000333/LER-1979-069, Forwards LER 79-069/03L-0 05000333/LER-1979-069-03, /03L-0:on 790908,recurrent Failure of Rod Block Monitor B Began.Caused by Failure of Low Power Range Monitor Loose Switch Connector & Sticky Contacts in Rod Info Relays. Replacement of Relay Card Eliminated Failures
References
LER-79-069-03L, LER-79-69-3L, NUDOCS 7910100354
Download: ML19209B719 (2)

LER-1979-069, /03L-0:on 790908,recurrent Failure of Rod Block Monitor B Began.Caused by Failure of Low Power Range Monitor Loose Switch Connector & Sticky Contacts in Rod Info Relays. Replacement of Relay Card Eliminated Failures

Event date:
Report date:
3331979069R03 - NRC Website

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POWER AUTHORITY OF THE STATE OF NEW YORK JAMES A. FITZPATRICK NUCLEAR POWER PLANT DOCKET N0. 50-333 ATTACHMENT TO LER 79-069/031-0 Page 1 of 1 During normal operations, Rod Block Monitor B failed in an inoperable condition. Operations personnel conducted Operations Surveillance Test F-ST-5R, titled "RBM Upscale and Downscale Instrument Functional Test" to demonstrate the operability of Rod Block Monitor A. Investigation revealed that LPRM Card No. 40-12-13 had failed, resulting in an improper input to Rod Block Monitor B. On September 10, 1979, Rod Block Monitor B failed in an inoperable condition when Control Rod 26-07 was selected for withdrawal. Completion of F-ST-5R demonstrated that Rod Block Monitor A was operable and investigation revealed a loose switch connector. Tightening of the connector restored the Rod Block Monitor to an 0perable condition. On September 13, 1979, Rod Block Monitor B failed downscale resulting in a rod block. Investigatior. revealed sticky contacts associated with the relays which communicate selectcd rod information from the Reactor Manual Control System to the Rod Block Monitor System. The Rod Block Monitor A was demonstrated operable by the satisfactory completion of F-ST-5R. On September 14, 1979, Rod Block Monitor B again failed downscale. Rod Black Monitor A was demonstrated operable by the completion of F-ST-5R and the difficulty was traced to the relays which communicate tne rod select information to the Rod Block Monitor. During each of the above failures of Rod Block Monitor B, the redundant Rod Block Monitor was demonstrated operable per Technical Specification Appendix A Table 3.2-3 and no control rod movement was attempted. Therefere, the events did not represent any significant hazard to the public health and safety. Replacement of the relay card associated with Rod Block Monitor B eliminated the repeated failure of the instrument and proper operation was demonstrated by successful completion of F-ST-5R. il3b 334 }}