ML20086F906

AO 75-71:on 751107,cracked Weld on 1-inch Line to Relief Valve RV-35B Observed.Caused by Throttling MO-2-10-154B Resulting in Cracked Weld.Repairs Completed in Accordance W/Approved Procedure

ML20086F906
Person / Time
Site:	Peach Bottom
Issue date:	11/17/1975
From:	Cooney M PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	Boyd R Office of Nuclear Reactor Regulation
Shared Package
ML20086F909	List: ML20086F906 ML20086F911
References
AO-75-71, NUDOCS 8401090648
Download: ML20086F906 (2)

Text

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PHILADELPHIA ELECTRIC COMPANY 2301 MARKET STREET PHILADELPHI A. PA.19101 (215)04140oo , ,.

November 17, 1975 - ..<<3 Mr. Roger S. Boyd -

p%,gf s rQ l*I ,. ,lk) n.. .h Acting Director b '

Division of Reactor Licensing .t[)'978 _ h Office of Nuclear Reactor Regulations

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United States Nuclear Regulatory Commission Washington, DC 20555 M

Subject:

Abnormal Occurrence The following occurrence was reported to Mr. Jim Partlow, Region 1, Office of Inspection and Enforcement, Uni ted States Nuclear Regulatory Commission, on November 8,1975 Wri tten notifi cation was made to Mr. James P. O'Reilly, Office of Inspection and Enforcement, Region 1, United States Nuclear Regulatory Commission on November 10, 1975 In accordance with Section 6.7 2.A of the Technical Speci fications, Appendix A of DPR-44 for Unit 2 Peach Bottom Atomic Power Station, the following report is Scing submitted to the Directorate of Reactor Licensing as an Abnormal Occurrence.

Reference:

License Number DPR-44 Tedhnical Speci fication

Reference:

1 0.D.5 ,

Report No.: 50-277-75-71 Report Date: November 17, 1975 Occurrence Date: November 7, 1975 Faci li ty: Peach Bottom Atomic Power Station R.D.1, Delta, Pennsylvania 17314 Identification of Occurrence: -

,. 3 Cracked wcld on 1 inch line to relief valve RV-35B.

Condi tions Prior to Occurrence:

Reactor shutdown and depressurized. Reactor head removed and RHR "B" loop in operation in shutdown cooling mode.

Descri ption of CS .urrence:

While "B" RHR loop was operating in the shutdown cooling modo, l

a water leak was observed in t,he vicinity of the M0-2-10-154B valvo.

A cracked socket wcld where this 1" pipe connects tc a socket on the 24" l

header was identified as the source of Icakage.

l 0401090648 751117 gDRADOCK05000 ggy 00P SENT REGION _ - _

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.> *T Mr. Roger S. Boyd 50-277-75-71 Page 2 November 17, 1975 Designation of Apparent Cause of Occurrence.

Because the RHR system was operating in the shutdown cooling mode with low heat loads it was necessary to throttle the M0-2-10-154B val ve . This caused vibration which cracked the weld.

Analysis of Occurrence:

The safety implications of this occurrence are minimal because the leakage did not impair the RHis system's ability to deliver design flow. Liquid ef fluent from the leak was safely The Icak was contained to the immediate area in the torus room.

located external to the isolation valves.

Corrective Action:

Repairs have been completed in accordance with approved procedure. The Philadelphia Electric Company Engineering Department has reviewed the supports for this line and has recommended additional braci ng. This bracing vill be installed af ter approval by the l organization that performed the original design is obtained. l i

Failure Data:

None.

Very truly yours,

f.

• M. J. Cooney #^ Nb Superintendent Generation Division - Nuclear cc: Mr. J. P. O 'Rei lly Director, Region 1 Of fice of Inspection and Enforcement U. S. Nuclear Regulatory Commission 631 Park Avenue King of Prussia, PA 19406 n y,- .. , w .-,-- ~ . -. --r, ,

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