ML20009H361

LER 81-042/03L-0:on 810701,during Shutdown,Source Range Instruments NI-1 & 2 Found Not Responding as Expected. Cause Unknown.Operability Checks Satisfactory.All Nuclear Detectors Replaced

ML20009H361
Person / Time
Site:	Crystal River
Issue date:	07/29/1981
From:	Charles Brown FLORIDA POWER CORP.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML20009H360	List: ML20009H359 ML20009H361
References
LER-81-042-03L, LER-81-42-3L, NUDOCS 8108100014
Download: ML20009H361 (2)

Text

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,J 61 DOCKET NUMBER 68 69 EVENT DATE 74 75 REPORT DATE EVENT DESCRIPTION AND PROE ABLE CONSEQUENCES h l o 12 l l At 0330 during shutdown following a Reactor trip,it was determined that source range l

o ;3l l instruments N1-1 & 2 were not responding as expected. This created an event contrary l lo l4j l to T.S. 3.3.1.1. Maintenance was initiated and operability was restored at 0630. l l o i s i I There was no ef fect upon the health or safety of the general public. This was the j l o 161 l first occurrence of this . type,and this is the seventh event reported under this l j o l 7 l l Specification. l 10181 l l 80 7 8 g SY S T E '.1 CAUSE CAUSE COMP. VALV E CODE CODE SUBCODE COVPONENT CODE SLBCODE SUBCODE lol9l l Il Cl@ l X l@ l Z l@ l Il Nl Sl T[ Rl Ul@ l 1.]@ l Z [ @ 18 19 20 7 8 9 10 11 12 13 SEQUENTI AL OCCURRENCE REPORT REVISION pp qo EVENT YEAR REPORT NO. CODE TYPE N O.

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CAUSE OESCRIPTION AND CORRECTIVE ACTIONS lijo)]The cause of this event is indeterminate. At the time of discovery, recorder NI-9-NR l All

,  ;,; ;was not recording as expected and NI 162 were in agreement with the recorder. g operability checks were satisfactory,and all instrumentation was properly responding  ;

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Report No.: 50-302/81-042/03L-0 Facility: Crystal River Unit 3 Report Date: July 29,1981 Occurrence Date: July 1, 1981 Identification of Occurrence:

Source range instruments did not respond as expected, and this created an event contrary to Technical Speci-fication 3.3.1.1.

Conditions Prior to Occurrence:

Mode 3 hot shutdown (0%).

Description of Occurrence:

At 0330 during shutdown operation following a Reactor t:1p, it was observed that Recorder NI-9-NR was not recording a decay of source range counts as expected.

It was straight-lining at a low count rate level.

Source range indicators NI-l and NI-2 were observed to be in agreement with the recorder. Maintenance was initiated,and the instruments were declared operable at 0630.

Designation of Apparent Cause:

The cause of this event is indeterminate. Operability checks were satisfactory and did not reveal any condition to which the event could be attributed.

Analysis of Occurrence:

There was no effect upon the health or safety of the general public.

Corrective Action:

All instrumentation was responding properly upon completion of the operability checks. Although not related to this event, all nuclear detectors have been replaced,and all the detectors' checked out satisfactorily.

Failure Data:

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This was the first occurrence of'this type,and this is the seventh event under this Specification, t

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