ML19329B884

LER 77-116/03L-0:on 771228,during Auxiliary Feed Pump Monthly Surveillance Test,Turbine 1-2 Speed Control Lost & Declared Inoperable.Caused by Design Deficiency.Blown Control Power Fuse & Both Relays Replaced & Modified

ML19329B884
Person / Time
Site:	Davis Besse
Issue date:	01/18/1978
From:	Beyer B TOLEDO EDISON CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML19329B878	List: ML19329B876 ML19329B884
References
LER-77-116-03L, LER-77-116-3L, NUDOCS 8002060884
Download: ML19329B884 (2)

Text

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60 61 DOCKET NUM8ER 68 69 EVENT DATE 74 75 REPORT DATE 80 EVENT DESCRIPTION AND PROBABLE CONSEQUENCES h I a121l At 1600 hours0.0185 days <br />0.444 hours <br />0.00265 weeks <br />6.088e-4 months <br /> on 12/28/77 during the performance of ST 5071.01. "Auxiliarv Feed P ,-n o ,3 (AFP) Monthly Surveillance Test", Auxiliary Feed Pump Turbine (AFFT) 1-2 speed control l

l o i4 l l was lost. AFP l-2 was declared inoperable placing the unit in the Action Statement There1 o I s 1 I of Tech Spec 3.7.1.2, which requires two independent AFPs in Modes 1, 2 and 3.

personnel. The re- 1 o is ] l vas no danger to the health and safety of the oublic or to unit l

0 } 7 } l dundant AFP was available to supply feedwater if a main steam line or f eedwater break 1

o,s,j had occurred. (NP-33-77-116) 80 SLBCOdE SU E CoOE SUSC E COMPON ENT CODE E

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[41Y l@ l42Y l@ 43 44 47 27 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS The relays used in the l

,,ojlThe cause of this occurrence is a design deficiency.

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,,,,g AFPT speed control circuit evidently cannot function without contact stickinc under operating conditions. The blown control power fuse and both relays in AFP l-2 speed .l

, g A modification has been completed which replaces the [

, , gcontrol circuits were replaced.

relays with a relay capable of operating in the circuit under design condit_ ions. 80 LLI 18 9I 7

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% POWER oTHER STATUS ST Ah 5 l l l Bl@lSurveillanceTesting l i s3 l9d @ l 0l 714l@lNA 10 12 13 44 45 46 80 7 "

ACTIVITY CON TENT LOCATION OF RELEASE AMOUNT oF ACTIVtTV l NA T.ELESSED OF RELE ASE I I li 181 i 7 8 9 l@I 10 l@l NA 11 44 45 80 PERSONNEL EXPOSURES NUMBER TYPE DESCRIPTION ]

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Bernie Beyer PHONE: /414) 259-5000. Wr . 223E nvu 141-1 , , , . . . . . . . , , , , ,

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TOLEDO EDISON COMPANY DAVIS-BESSE UNIT ONE NUCLEAR POWER STATION p -

SUPPLEMENTAL INFORMATION FOR LER NP-33-77-116 I 7 <

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DATE OF EVENT: December 28, 1977' FACILITY: Davis-Besse Unit 1 IDENTIFICATION OF OCCURRENCE: Auxiliary Feed Pump 1-2 speed control was lost.

Conditions Prior to Occurrence: The unit was in Mode 1, with Power (MWT) = 2064 c.nd Load (MWE) = 689.

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Description of Occurrence: At 1600 hours0.0185 days <br />0.444 hours <br />0.00265 weeks <br />6.088e-4 months <br /> on December 28, 1977 durinr the perfor- '

mance of ST 5071.01, " Auxiliary Feed Pump Monthly Surveillance Test", Auxiliary Feed Pump Turbine (AFPT) 1-2 speed control was lost. Auxiliary Feed Pump 1-2 was declared inoperable placing the unit in the Action Statement of Technical Specification 3.7.1.2, which requires two independent Auxiliary Feed Pumps in Modes 1, 2 and 3.

i Designation of Apparent Cause of Occurrence: The cause of this occurrence is a design deficiency. The relays used in the AFPT speed control circuit evidently innot function without contact sticking or arcing under operating conditions.

_jticking or arcing contacts cause the control power-fuses to blow, resulting in c loss of speed control to the Auxiliary Feed Pump Turbine.

' Analysis of Occurrence: There was no danger to the health and safety of. the public or to unit personnel. Auxiliary Feed Pump 1-1 was operable to supply feedwater if a main steam line or feedwater break had occurred.

Corrective Action: The blown fuse and both of the relays in Auxiliary Feed Pump Surveillance Test ST 5071.01, " Auxiliary 1-2 speed control circuits were replaced.

Feedwater Monthly Test" was completed at 1730 hours0.02 days <br />0.481 hours <br />0.00286 weeks <br />6.58265e-4 months <br /> on December 28, 1977, return-

)' ing Auxiliary Feed Pump 1-2 to opocable status. This removed the unit from the

. Action Statement of Technical Specification 3.7.1.2 well within the 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> limit.

A modification has been designed and, installed which adds a relay capable of operat-ing in the motor contact portion of the circuit under design conditions.

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Failure Data: There have been other failures due to blown fuses in the AFPT speed l

control circuits,.several before a modification was made to reduce current load on relay contacts and two (one on AFP l-1 and one on AFP 1-2) since the modifica-tion was made on the Auxiliary Feed Pumps. All of the above failures occurred prior to the modification which added the additional relays.

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