ML20092C641

Special Rept:On 950806,containment Area RM R-27A Declared Inoperable Due to Instrument Displaying Invalid Alarm.Caused by Failed Connector Seal.Connector Seal Replaced & RM R-27A Returned to Operable Status on 950813

ML20092C641
Person / Time
Site:	Farley
Issue date:	09/08/1995
From:	Woodard J SOUTHERN NUCLEAR OPERATING CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 9509130076
Download: ML20092C641 (2)

Text

. , . .- Southern Nucielr Opertting Company Post Omco Box 1295 Birmingham. Alabama 35201.

T;tephoru (205) 868 5086

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.i. o. woon.ro Southem Nudear. Operating Company i Executive Vce President September 8, 1995 Docket No. 50-364 10 CFR 50.4 U. S Nuclear Regulatory Commission ATrN: Document Control Desk Washington, D. C. 20555 Joseph M. Farley Nuclear Plant - Unit 2 Special Reoort No.95-001. Inocerable 'R-27A Fadiatina Monitor L.adies and Gentlemen-In accordance with the requirements of Technical Specification 3.3.3.1, the enclosed Special ,

Report No.95-001, Unit 2, is submitted.

Respectfully submitted, J.

Enclosure DPH:maf SPRR27A. DOC cc: Mr. S. D. Ebmter Mr. B. L. Siegel Mr. T. M. Ross i

La c r"' C G p 1 9509130076 950908 gDR ADOCK 05000364 1\

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I Special Report for Inoperable Radiation Monitor i

This Special Report is being submitted in accordance with Technical Specification 3.3.3.1 due to the fact that the Unit Two Containment Area radiation monitor R-27A was not restored to operable status within 7 days.

On August 6,1995 at 1015 R-27A was declared inoperable due to the instrument displaying an invalid alarm. Previous experience and vendor recommendations indicated  :

the most likely cause of the observed problem was a failed connector seal located at the detector. The connector seal was replaced, and functional testing, which included detector response to a 6 R/hr source, was performed satisfactorily. R-27A was returned t to operable status on August 13,1995 at 0907, On August 19,1995 at 1400 R-27A was declared inoperable due to the instrument displaying an invalid alarm. An investigation initially indicated that the self-check feature of the instrument may have resulted in the instrument going into an unwarranted alarm condition. Corrective maintenante was performed on the self checking circuit which periodically verifies cable continuity and detector operability. Two capacitors associated with this circuit were replaced, and functional testing was completed satisfactorily. R-27A was considered operable at 2210 on August 22,1995. However, at 0924 on August 23,1995, R-27A was declared inoperable due to the instrument intermittently displaying an invalid alarm. Following this occurrence, the detector and instrument drawer were replaced, however, R-27A continued to alarm intermittently.

Additional testing indicated the invalid alarms are apparently due an intermittent failure ,

occurring inside a field connector returning from the detector. The field connector will be '

repaired and appropriate testing performed as soon as repair parts become available.

Corrective action is tentatively scheduled to be completed by September 15,1995.

! Based on several days of observation following corrective maintenance and testing

! associated with the August 6,1995 failure, the August 19,1995 failure is attributed to a ,

[ different failure mechanism. This Special Report is being submitted based on failing to

! restore R-27A to operable status within 7 days beginning August 19,1995, i

j During the periods when R-27A was inoperable, R-27B remained operable.

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