ML19317F834
| ML19317F834 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 06/18/1975 |
| From: | Mattimoe J SACRAMENTO MUNICIPAL UTILITY DISTRICT |
| To: | NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| Shared Package | |
| ML19317F835 | List: |
| References | |
| NUDOCS 8002210582 | |
| Download: ML19317F834 (2) | |
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St.CPA'.tLNTO MUNICIPAL UTluiY DISTRICT,* 170S 59th Street. Bos 15S30. Sacrarrento. Cahforrua 95813;(516) 85 3:11 June 18, 1975 i
Director-Division of Reacto'r Licensing U.S. Nuclear Regulatory Conmission
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' Washington, D.C.
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Re: Operating License DPR-54 Docket No. 50-312 Abnormal Occurrence 75-10
Dear Sir:
_As defined by proposed Amendnent No. 30 to. Technical Specifications for the Rancho-Seco Nuclear Generating Station, Section 6.9.1 and Regulatory Guide.1.16', Rev. 3, Section C.2.b.(2), we are reporting the following Abnor-mal Occurrence as A0-75-10.
,b3 On May 19, 1975, during the performance'of Surveillance Procedure d
SP 210.01A, " Auxiliary Feed Pump P-318 Periodic Testing",;the pump stopped running shortly after the initial start. A check of the motor breaker indicated that a cine. delay overcurrent ' trip had actuated.
The feedwater pu=p has tvo pri=e covers, an electric motor and a steam turbine. An independs.c test was initiated using the stea: turbine drive to check the pump for possible binding. The pump operated properly throughout the test.
Another test was perfor=ed using the motor and again, after'a short period' of time, the unit. tripped on overcurrent. An electrical technician found the phase.2 relay had a loose locking nut on the I-th element plunger, vhich changed the overcurrent delay circuit trip setting.
The circuit test of each. relay el, :2 and :3 indicated the overcurren <ceting to he 21 amperes instead of the correct value of 23 amperes.
The loose nut on'the plunc;ct vas tightened, each relay in-the breaker l
cabinet mechanically inspected for loose connections and the relays were reset to the design load requirements. The auxiliary feedvater motor
^ windings were negger and resistance checked to verify the integrity of the cotor. The motor drive was succe:mfully tested and passed the surveillance requirements on May 21, 1975.
To. prevent reoccurrence of this event, a preventive maintenance program will be-initiated within 90 days to check the overeurrent - relay settings of all Class I equipnent. The planned retent schedule will bc three voars as specified by the manufacturer.
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i Director i '
Divisien of Reactor Licensing June 18, 1975 l
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i the relay is canufactured b: Festinghouse Electric Corporation 4
l Relay Instrunent Division in Newark, New Jersey and is 31odel C031-5, Style 2893355A17.
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There was no transient associated with this occurrence.
I Respectfully, i
l J. J. !!attimoe Assistant General 31anager and Chief En ineer g
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