05000346/LER-1977-090-03, /03L-0:on 771107,during Review of Deficiency in Steam & Feedwater Rupture Control Sys Monthly Test,Reactor Coolant Pump Found Inoperable.Caused by Component Failure. Voltage Regulating Diode Replaced

/03L-0:on 771107,during Review of Deficiency in Steam & Feedwater Rupture Control Sys Monthly Test,Reactor Coolant Pump Found Inoperable.Caused by Component Failure. Voltage Regulating Diode Replaced

ML19326A510
Person / Time
Site:	Davis Besse
Issue date:	12/01/1977
From:	Mitchell D TOLEDO EDISON CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML19326A493	List: 05000346/LER-1977-090, Forwards LER 77-090/03L-0 05000346/LER-1977-090-03, /03L-0:on 771107,during Review of Deficiency in Steam & Feedwater Rupture Control Sys Monthly Test,Reactor Coolant Pump Found Inoperable.Caused by Component Failure. Voltage Regulating Diode Replaced
References
LER-77-090-03L, LER-77-90-3L, NUDOCS 8002040697
Download: ML19326A510 (2)

LER-1977-090, /03L-0:on 771107,during Review of Deficiency in Steam & Feedwater Rupture Control Sys Monthly Test,Reactor Coolant Pump Found Inoperable.Caused by Component Failure. Voltage Regulating Diode Replaced

Event date:
Report date:
3461977090R03 - NRC Website

text

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

U.S. NUCLEAR REGULATORY COMMISSION

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NRC F!RM 366 (7 77r LICENSEE EVENT REPORT

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EVENT DESCRIPTION

AND P_ ROB ABLE CONSEQUENCES h in the SFRCS

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I o 8 2 I I At 1310 hours0.0152 days <br />0.364 hours <br />0.00217 weeks <br />4.98455e-4 months <br /> on November 7, 1977, during a review of a deficiency m m 101311 Mon hiv Tes't. aoNblemaffectingthe~RPSwasfound. One of the four RCP monitors

- l RPS E "5T"T4 frc$%di-VW2--2'T-gocreo RPR. Channel. 21 was _ determined to be_. inoperable.

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'I o I si F-channel -vas-declaredcinneerabia and tripped which placed. the statiott in Action _

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3' oflechnica1 Soecific'attorr 3.Y.l.1.- The redundant.aPS channels, wouid _.

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current eni+or. had. a.def ective_ voltage.iragulating. :ener-diede. Cn

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The cha'anel_ was. d.clared. operable at 1405 hours0.0163 days <br />0.39 hours <br />0.00232 weeks <br />5.346025e-4 months <br />..on. November. 10, 1977. whic'a 1

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DAVIS-BESSE UNIT ONE NUCLEAR POWER STATION SUPPLEMENTAL INFORMATION FOR LER NP-33-77-90 DATE 0F EVENT: November 7, 1977 ACILITY: Davis-Besse Unit 1 IDENTIFkCATIONOF0CCURRENCE: -Inability of Reactor Protection System. (RPS). Channel -

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. 2 to-recognize a locked rotor. (hig&L. current) condition. for. Reactor.-Coolant Pump,__.

(RCP) motor 2-2.

Conditions"FIior co Occurrenew-l The. unit -was, in Mode-2gi:th Power..(MWI) = 0 and

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Load (MWE) = 0.

Desci:1 priori of'0Feurrence: Ar L340: hours-on November 7,1-972,..during a review of.

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a deficiency ~in the Steam and: F7eeiiwEei.'tGipture Control Systam. ;(SFRCS) Monthly _,

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Test, ST 5031.14, a problem gffecting the RPS was found.

One of the four RCP m'onitors from RCF; motor 2-2 (-going.to RPS Channel 2) _was determined. to be..inopera j

..g-ble such char the RPS Channeiv2 would not-recognize a; locked rotor condition of.

- the-2-2 pump motor. This -does. pat--affect the SFRCS since...it. ia concerned with loss of power to all four pump. motors, but does affect the-RPS.

The Technical Engineer was no.tified..and at 1335-hours, RPS Channel 2 was declared cinoperable and tripped which -placed the unit-in the Action;Stacament 3.of -Tech. -;;..

nical Specification (TS) 3.3.1,.l.

Designatiotr oF Apparent Causeiof Occurrence: Component failure was the cause of., -

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this occurrence. A current ep;yoitage transducer if RCP. motor current monitor had a defective voltage regulating-zener diode.

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- -Analysis -of-Odedrrence: - Thergy--no -danger to.- the health ansi. safety.of the.public,.. --

or to station personnel. The redundant RPS channels would'have limited reactor.

power--if an overcurrent trip had -occurred.

Corrective Action

On November 10, 1977, the voltage-regulating sener diode was replaced. The transducer was reinstalled and the calibration was_ satisfactorily -

'chec'ked.MTST-5031.14;."SFRCS Monchly. Test",.was performed for RCP

• 2-23 RES J.hannel--/ 5 --

m-e 2 and a new _ response time check..was satisf actorily. perforced,. ~3-C m Tfie cha5 net %zs de51ared operable at 1405-hodrsr on Novembep40m117.7, which, removed.. :,

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the station fr-om action Statetsent 3 of TS 3.3.1.1.-

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Failure-Dees: No previous failures of these transducers have occurred.

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