ML19323B452

LER 80-034/03L-0:on 800411,during Auxiliary Feed Pump Instrumentation Calibr Test,Turbine 1 Steam Inlet Pressure Switch PSL-106B Actuated at Pressure Above Setpoint.Caused by Failure of Static O-ring Pressure Switch

ML19323B452
Person / Time
Site:	Davis Besse
Issue date:	05/07/1980
From:	Trautman D TOLEDO EDISON CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML19323B450	List: ML19323B449 ML19323B452
References
LER-80-034-03L, LER-80-34-3L, NUDOCS 8005120391
Download: ML19323B452 (2)

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[olil l (NP-33-80-44) On April 11, 1980 at 0630 hours0.00729 days <br />0.175 hours <br />0.00104 weeks <br />2.39715e-4 months <br /> during the performance of Auxilary [

[a;3j g Feed Pump Instrurentation Calibration Test ST 5071.03, Instrument and Controls person-l yol,,[]nelfoundthat the Auxiliary Feed Pump Turbine 1 Steam Inlet Pressure Switch PSL-106B l Being in Mode 5, the lo i s i I actuated at a pressure above its desired setpoint 9 1 1 psig. l 10 It> J l station did not enter the action statement of Technical Specification 3.7.1.2 which l This l 0 l 7 l l requires both auxiliary feedwater systems to be operable in Modes 1, 2, and 3. l inig; joccurrence is being reported to document a component failute. [

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au CAUSE DESCRIPTION AND CORRECTIVE ACTIONS 27

)ijallThe cause of the occurrence is the failure of Static 0-Ring pressure switch Model 6V2 g g,g,g lE2-T1X4. The switch was recalibrated, but tests for repearnbility proved unsuccessfu14

,,,;,, j This defective pressure switch was replaced under Maintenance Work Order IC-346-80 [

,,,,,gand was completed April 19, 1980. The failed switch will be returned to the vendor l

, , , ,, y g Static-0-Ring for their analysis. l 80 7 8 9 STA s *. PO?sE R OTHER STATUS DlS O RY DISCOVERY DESCRIPTION ST 5071.03 i 5 [Ilj@ l0l0l0l@l NA l l Blgl Surveillance Test l ACTIVITY CO TENT HELE ASED OF RELE ASE AMOUNT OF ACTIVITY LOCAleON OF RELEASE l1l6l g lZ l 10 l NA 44 l l NA 45 80 l

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DVR 80-064 N A?. E OF PREPARER anM hauMan PHONE:,

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DAVIS-BESSE NUCLEAR POWER STATION UNIT ONE

' SUPPLEMENTAL INFORMATION FOR LER NP-33-80-44 5 DATE OF EVENT: April 11, 1980 I FACILITY: Davis-Besse Unit 1 l

l IDENTIFICATION OF OCCURRENCE: Auxiliary Feedwater (AFW) Turbine Steam Inlet Pressure

! Switch PSL-106B Out of Calibration Conditions Prior to Occurrence: The unit was in Mode 5, with Power (MWT) = 0, and I Load (Gross MWE) = 0.

l Description of Occurrence: On April 11, 1980 at 0630 hours0.00729 days <br />0.175 hours <br />0.00104 weeks <br />2.39715e-4 months <br />,during the Auxiliary Feed Pump Instrumentation Calibration Test, ST 5071.03, Instrument and Control (I&C) per-sonnel discovered that PSL-106B Auxiliary Feed Pump Turbine 1 Steam Inlet Pressure Switch, actuated at a pressure above its desired tolerance. The desired setpoint is 9 i 1 psig. The switch actuated at 18.52 psig decreasing. Actuation of steam inlet pressure switches PSL 106B and PSL 106D or PSL 106A and PSL 106C, on low steam pres-i sure, will secure incoming steam to the Auxiliary Feed Pump Turbine from both steam generators. This occurrence did not place the unit in the action statement of Tech-nical Specification 3.7.1.2. This Technical Snecification requires both Auxiliary Feedwater Systems to be operable in Modes 1, 2, and 3. The unit was in Mode 5 at the l time of the occurrence. This occurrence is being reported to document a component failure.

Designation of Apparent Cause of Occurrence: The cause of the occurrence has been determined to be a failure. of Static 0-Ring pressure switch (Model 6V2-E2-TTA). The pressure switch was removed from the system and bench calibrated where various pres-sures were maintained on the pressure switch for a period of time. Tests for repeata-j bility proved unsuccessful under these conditions. The cause of this setpoint drift t

requires cendor resolution.

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2 Analysis of Occurrence: There was no danger to the health and safety of the public i or to station personnel. The redundant pressure switch, PSL 106D actuated within l tolerance and showed no signs of non-repeatability during performance of surveillance test ST 5071.03.

Corrective Action: The defective pressure switch was removed from the AFW system, bench tested and disassembled to investigate for signs of wear, corrosion, binding, Investigation revealed no apparent cause for the non-repeatability of the 1

etc.

pressure switch (PSL-106B). The defective pressure switch (Static 0-Rin'g 6V2-E2-TlX4, Serial No. 76-9-2594) was replaced. The above work was performed under Maintenance Work Order IC-346-80 and was completed April 19, 1980. The failed switch will be returned to the vendor for analysis.

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! Failure Data: Previously reported failures of Static 0-Ring pressure switches were

reported in Licensee Event Reports NP-33-79-64 (79-062) and NP-33-79-82 (79-074).

LER #80-034 ~

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