ML19242A183

LER 79-069/03L-0 on 790623:during Performance of Surveillance Testing,Containment post-accident Radiation Monitor Re 5029 Had Low Flow Alarm & Was Declared Inoperable.Caused by Loose Sheave Set Screws

ML19242A183
Person / Time
Site:	Davis Besse
Issue date:	07/19/1979
From:	Adams J TOLEDO EDISON CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML19242A168	List: ML19242A167 ML19242A183
References
LER-79-069-03L, LER-79-69-3L, NUDOCS 7907310473
Download: ML19242A183 (2)

Text

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DATE EVENT DESCRIPTICN AND PROBABLE CONSEQUENCES h o 2 l On June 23, 1979. during the perf ornance of surveillance testin;, it was noted that l RE 5029 o 3 l Conta inment Post-Accident Radiation Monitor RE 5029 had a low flow alarm. l g .

was subsequently declared inoperable. Since the unit was in Mode 5 at the time of l g 3 l this occurrence, no action statements were applicable. This report is being srbaitteq o e L s a cum at ti a f in rrect aint n ac . There was no danger to the health and ,

safety of the .blic or station personnel. The other contaittient pos t-accident radia-a 7 g

tion monitor, RE 5030, was operable throughout this occurrence (NP-33-79-76)

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44 47 Jo 36 Je CAUSC DESCRIPTION AN$ CORRECTIVE ACTIONS h L: 19J ' h sheave set screus became loose, possibly due tc insufficient set screw tighteningj i during maintenance. On June 23, 1979, the pump sheave was replaced, the set screws l i i

,;7; i were tightened, and the belt reinstalled. The bi-monthly pump replacement preven- l 3 , l tive maintenance bork order has been revised to include a step to ensure that the

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DAVIS-BESSE NUCLEAR POWER STATION UNIT ONE SUPPLEMENTAL INF0"IATION FOR LER NP-33-79-76_

DATE OF EVENT: June 23, 1979 I

FACILITY: Davis-Besse Unit 1 IDENTIFICATIO.i 0F OCCURRENCE: Containment Post-Accident Radiation Monitor RE 5029 .

was inoperabic  !

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Conditions Prior to Occurrence. The unit was in Mode 5, with Power (>Rif) = 0, and Load (Gross BNE) = 0.

Description of occurrence: During performance of Surveillance Test ST 5032.01,

" Monthly Functional Test of the Radiation Monitors", on June 23, 1979, it was no-ticed that Containment Post-Accident Radiation Monitor RE 5029 had a low flow alarm.

Investigation showed that the belt and pump sheave had come of f. RE 5029 was de-clared inoperable at 0515 hours0.00596 days <br />0.143 hours <br />8.515212e-4 weeks <br />1.959575e-4 months <br /> on June 23, 1979.

Technical Specification 3.3.3.1 requires the operability of one radiation monitoring channel in Modes 1, 2, 3, and 4. Technical Specification 3.4.6.1 requires he opera -

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bility of containment annosphere particulate and gaseous radioactivity monitoring g in Mudco 1, 2, 3, and 4. Since the unit was in Mode 5 at the time of the accurrence. 4 neither or the Action Statements of these Technical Specifications was. applicable.

This report is,bging scbmitted as documentation of incorrect mair.tenance.

Designation of Apparent Cause of Occurrence: The cause of the occurrence could have been due to insufficient set screw tightening during maintenance. The sheave set screws loosened, causing the sheave and belt to come off.

s Analysis of Occurrence- There was no danger to the health and sa fety of the public or to station personnel. The other containment post-accident radiation monitor, RE 5030, was operabic during the period that RE 5029 was inoperable. The unit was in hade 5 at the time of the occurrence.

,Correc tive Act ion: On June 23, 1979, under Maintenance Work Order (BGO) 79-2377, b..intenance personnel replaced the pump sheave, tightened the set screws, and re-installed the belt. There has been an annual preventive naintenance work order initiated to check belt condition, tightness, and set screw tightness. The bi-monthly pump replacement preventive MWO has been revised to include a step to ensure the sheave set screws are tight.

Failure Data: Although thore have been failures of the radiation monitors, there have been no failures caused by loosening of set screws.

LER #79-069 fj $ b