05000302/LER-1979-104-03, /03L-0:on 791028,remote Shutdown Indicator for Decay Heat Cooler Outlet Temp DH-40-TI Was Inoperable.Caused by Loose Precision Resistor Assembly.Resistor Bridge Assembly Tightened & DH-40-TI Returned to Svc

/03L-0:on 791028,remote Shutdown Indicator for Decay Heat Cooler Outlet Temp DH-40-TI Was Inoperable.Caused by Loose Precision Resistor Assembly.Resistor Bridge Assembly Tightened & DH-40-TI Returned to Svc

ML19253C326
Person / Time
Site:	Crystal River
Issue date:	11/20/1979
From:	Lancaster K FLORIDA POWER CORP.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML19253C314	List: 05000302/LER-1979-104, Forwards LER 79-104/03L-0 05000302/LER-1979-104-03, /03L-0:on 791028,remote Shutdown Indicator for Decay Heat Cooler Outlet Temp DH-40-TI Was Inoperable.Caused by Loose Precision Resistor Assembly.Resistor Bridge Assembly Tightened & DH-40-TI Returned to Svc
References
LER-79-104-03L, LER-79-104-3L, NUDOCS 7911300522
Download: ML19253C326 (1)

LER-1979-104, /03L-0:on 791028,remote Shutdown Indicator for Decay Heat Cooler Outlet Temp DH-40-TI Was Inoperable.Caused by Loose Precision Resistor Assembly.Resistor Bridge Assembly Tightened & DH-40-TI Returned to Svc

Event date:
Report date:
3021979104R03 - NRC Website

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Reference LER 79-095.

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SUPPLEMENTARY INFORMATION Report No.:

50-302/79-104/03L-0 Facility:

Crystal River Unit #3 Report Date:

20 November 1979 Occurrence Date:

28 October 1979 Identification of Occurrence:

Remote shutdown indicator for "B" decay heat cooler outlet temperature DH-40-TI inoperable, contrary to Technical Speci-fication 3.3.3.5.

Conditions Prior to Occurrence:

Mode 1 power operation (100%).

Description of Occurrence:

At 0400 during the performance of Daily Operating Surveillance SP-300 it was reported that the remote shutdown indicator for "B"

acay heat cooler outlet temperature, DH-40-TI was inoperable.

It was discover 9d that DH-40-TI (103*F) was inconsistent with redundant Control Room indicator DH-2-TI-2 (95*F) and "B" decay heat pump suction indicator DH-6-TI-2 (80 F).

Maittenance restored operability and DH-40-TI was returned to service at 0900 on 2 November 1979.

Designation of Apparent Cause:

The cause of this event is attributed to a loose precision resistor bridge assembly. The resistor bridge assembly was tightened and DH-40-TI was returned to service.

Analysis of Occurrence:

No effect upon the plant or general public.

Corrective Action

REI 79-10-11 has been initiated to evaluate decay heat remote shutdown temperature indication. Further corrective action will be based upon the results of this evaluation and submitted as a supplement to this report.

Failure Data:

This is the second occurrence reported for DH-40-TI.

Reference LER 79-095.

/rc 1444078