ML20086J152

AO 74-35:on 741208,deficient Support Found on Limitorque Motor on RHR Outboard Throttleable Reactor Injection Valve MO-3-10-154B.Caused by High Vibration During Shutdown Cooling Operation.Motor Stator Being Rewound

ML20086J152
Person / Time
Site:	Peach Bottom
Issue date:	12/18/1974
From:	Cooney M PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	Giambusso A US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20086J155	List: ML20086J152 ML20086J158
References
AO-74-35, NUDOCS 8401230262
Download: ML20086J152 (2)

Text

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• PHILADELPHIA ELECTRIC COMPANY ,

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' Mr. A. Giambusso Deputy Director of Reactor Projects United States Atomic Energy Commission Directorate of Licensing Washington, D.C. 20545

Subject:

Abnormal Occurrence The following occurrence was reported to Mr. Walt Baunack, '

, A.E.C. Region 1 Regulatory Operations Office on December 8, 1974.

Written notification was made to Mr. James P. O'Reilly, Region 1 Regulatory Operations Office on Decenber 9, 1974 In accordance with Section 6.7.2.A of the Technical Specifications, Appendix A of DPR-56 for Unit 3 Peach Botton Atomic Power Station, the following report is being submitted to the Directorate of Licensing as an Abnormal Occurrence.

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Reference:

License Number DPR-56 Technical Specification

Reference:

3.5.A.3 Report No.: 50-278-74-35 Report Date: December 18, 1974 Occurrence Date: December 8, 1974 Facility: Peach Bottom Atomic Power Station R.D. #1, Delta, Pennsylvania 17314 Identification of Occurrence:

Deficient support of limitorque motor on RHR outboard throt-tleable reactor injection valve (f D-3-lO-154B) .

Conditions Prior to Occurrence:

Unit shutdown. RHR operating in shutdown cooling mode.

Description of Occurrencer, Limitorque Motor support on MO-lO-154B vibrated loose allow-ing the motor to separate fror: the limitorque operator. During re-assembly it was discovered that the motor winding was grounded.

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Page 2 Mr. A. Giambusso December 18, 1974 o

Designation of Apparent Cause of Occurrencet l ingh vibration during shutdown cooling operation l t of this va ve to caused the cap screws which hold the motor to an adapter p a e loosen.

Analysis of Occurrence:

This occurrence caused the valve to fail in the "as is"the valve can be posi-l position.

During shutdown cooling operations, flow rate. liigh tioned manually to provide proper shutdown cooling in a throttling vibration is only present when the valve is operating  ;.

mode. During reactor operation this i s normally inldthe Therefore full openthe js not be position. minimal since the high vibration which caused the failure wou  !

present during reactor operation. e Corrective Action:

The motor stator is being rewound and will be fitted with new The danaged motor operator gear set bearings and completely tested.The unit will be reassembled using new cap screws will be replaced. The Philadelphia Electric secured with LOC-TITE and lock washers. is presently reviewing Company's Mechanical Engineering Department proposed modifications designed to reduce this vibration.

Failure Data:

Similar failures have occurred as reported in Abnormal Occurrence Report Numbers 50-277-74-53 and 50-278-74-28.

Very truly yours, l pou w

!]l]Cooney' M. .

Asst. Gen 1. Superintendent Generation Division

- cc: Mr. James P. O' Reilly Director, Region 1 United States Atomic Energy Commission 631 Park Avenue 19406 King of Prussia, PA i

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