ML20086F902

Telecopy AO 75-73:on 751113,leak on Body of RV-35B RHR Sys Relief Valve Observed.Caused by Throttling of MO-2-10-154B Valve Resulting in Crack.Rhr Loop B Shut Down in Preparation for Repair of Relief Valve

ML20086F902
Person / Time
Site:	Peach Bottom
Issue date:	11/14/1975
From:	Ullrich W PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML20086F900	List: ML20086F896 ML20086F902
References
AO-75-73, NUDOCS 8401090639
Download: ML20086F902 (1)

Text

Peach Bottom Atomic Por-~ Station  !

^

Delta, Pennsylvdj a

• 17314 November ~14, 1975 Mr. James P. O'Reilly, Director Office oP Inspection and Enforcement Regio'n 1 I United States Nuclear Regulatory Commission 631 Park Avenue .

King of P ossia, Pennsylvania 19406

Subject:

Abnormal Occurrence 2h-Hour Notification Confirming R. S. Fleischmann's verbal conversation with Mr. Walt Baunack, Region 1, United States Nuclear Regulatory Commission on November 14,1975 ,

Reference:

License Number DPR-kh Technical Specification

Reference:

3.5.A.h Report No.: 50-277-75-73 Report Date: November 14, 1975 Occurrence Date: November 13, 1975 Facility: Peach Bottom Atomic Power Station R.D. 1, Delta, Pennsylvania 17314 Identification of Occurrence:

Leak on body of RV-35B, RHR system relief valve.

Conditions Prior to Occurrence:

Reactor shutdown, depressurized, reactor head removed, and RHR "$"

loop shutdown cooling in operation.

Description of Occurrence:

While the "B" RHR loop was operating in the shutdown cooling mode, valve HV-35B vas observed to leak water. The upper portion of the valve ody had vibrated loose from the lower pcition at the threaded joint.

Designation of Apparent Cause of Occurrence:

Because the RHR system van operating in the shutdown cooling mode with lov heat loads, it was necessary to throttle M0J2-10 15hB. This causes vibration apparently resulting in the loosening of the i.alves of the relief valve body.

Analysis of Occurrence: '

The safety implications of this occurrence are minimal because the leakage, which was external to the isolation valves, did not represent significant impairment of the RHR system's ability to deliver design ,

flow. Liquid effluent from the leak was safely contained to the '

immediate area in the torus room.

Corrective Action:

The "B" RHR loop was shutdown in preparation for repair of the relle'f valve. The need for additional pipe restraints is being investigated.

Failure Data:

50-277-75-71 and 50-277-75-72. .

Very truly yours, ,

My , .m ._2 -w W. T. Ullrich, Superintendent '

Peach Bottom Atomic Power Station -

jd 8401090639 751121 -

PDR ADOCK 05000277 , ,

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