ML20010B497

LER 78-094/03X-1:on 780902,containment post-accident Radiation Monitor Re 5029 Observed Having Erratic Flow & Declared Inoperable.Caused by Component Failure of Motor on Pump.New Bearings & Solenoid Valve Installed

ML20010B497
Person / Time
Site:	Davis Besse
Issue date:	08/04/1981
From:	Schwenning L TOLEDO EDISON CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML17275B377	List: ML17275B376 ML20010B493 ML20010B495 ML20010B497 ML20010B499 ML20010B500 ML20010B501 ML20010B503 ML20010B504
References
LER-78-094-03X, LER-78-94-3X, NUDOCS 8108170102
Download: ML20010B497 (2)

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LICENSEE EVENT REPORT (PLE ASE PRINT OR TYPE ALL REQUIRED INFORMATION)

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10121 l OIP-33-78-111) On 9/2/78, containnent cost-accident radiation tionitor RF 5029 was ob-The l go g ,g served to have erratic flow and w.is declared inoperable by the Shift Supervisor.

l o 14 l l unit wals 'then placed in the act'.on statement of Technical Specification 3.3.3.6. 'Inere]

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was no danger to the health and safety of the public or station personnel. T_b redun- l l

n3 l dant post-accident radiation monitor, RE 5030, was operable.

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CAUSE OESCRIPTION AND CORRECTIVE ACTIONS h These moton have beenl

[g l The cause is due to component failure of the motor on the pump.

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[ g l drawing excessive current and failing at new bearings and a new solenoid valve were installed. FCRs78-159 l g l78-2139 and 78-2167

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TOLEDO EDISON COMPANY DAVIS-BESSE UNIT ONE NUCLEAR POWER STATION SUPPLEMENTAL INFORMATION FOR LER NP-33-78-111 DATE OF EVENT: September 2, 1978 FACILITY: Davis-Besse Unit 1 IDENTIFICATION OF OCCURRENCE: Containment Post-Accident Radiation Monitor RE 5029 inoperable.

Conditions Prior to Occurrence: The unit was in Mode 1, with Power (MWT)

= 2089, and Load (MWE) = 700.

Description of Occurrence: At 1356 hours0.0157 days <br />0.377 hours <br />0.00224 weeks <br />5.15958e-4 months <br /> on September 2, 1978, Contain-ment Post-Accident Radiation Monitor RE 5029 was observed to have erratic flow and, therefore, declared inoperable by the Shift Foreman. The unit was then placed in the Action Statement of Technical Specification 3.3.3.6, which requires post-accident monitoring instrumentation to be operable while the unit is in Modes 1, 2 or 3. The Action Statement requires that the inoperable unit be restored within 30 days or the unit must be placed in Hot Shutdown within the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.

Designation of Apparent Cause of Occurrence: The apparent cause of this 1 occurrence is a component failure of the motor en the pump. These motors have been drawing excessive current and failing at the high ambient temperatures.

Analysis of Occurrence: There was no danger to the health and safety of the public or to :ait personnel. The other post-accident radiation monitor, RE 5030, was operable during the period that RE 5029 was inoper-able.

Corrective Action: Under Maintenance Work Order 78-2139 and 78-2167 new I bearings and a new solenoid valve were installed. The unit from the Action Statement of Technical Specification 3.3.3.6 after completion of Surveillance Test ST 5032.01, " Monthly Functional Test of the Radiation Monitoring System", at 0145 hours0.00168 days <br />0.0403 hours <br />2.397487e-4 weeks <br />5.51725e-5 months <br /> Na September 16. ,

Facility Change Request (FCR)78-159 has been implemented to replace the i

inboard and outboard pump motor bearings with Fafnir #203PP and #205PP bearings. These bearings were packed with a grease which has a higher 1 temperature rating. In addition, the speed of the pumps in RE 5029 and RE 5030 was reduced as a result af FCR 78-521. This change will reduce the motor load and consequently decrease the pump wear and internal heating.

Failure Data: There have been numerous component failures of the Radia-tion Monitors, however, those pertaining to motor related failures include NP-33-78-30, NP-33-78-77 and NP-33-78-105.

LER #78-094

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