ML20086G248

AO 75-72:on 751109,crack in 3/4-inch Vent Line on RHR Piping Observed.Caused by Throttle of MO-2-10-1548 Valve Resulting in Crack.Repairs Completed in Accordance W/Approved Procedures

ML20086G248
Person / Time
Site:	Peach Bottom
Issue date:	11/19/1975
From:	Cooney M PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	Boyd R Office of Nuclear Reactor Regulation
References
A-75-72, A0-75-72, AO-751119, NUDOCS 8401100174
Download: ML20086G248 (2)

Text

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YHILADELPHIA ELECTRIC COMPANY

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PHILADELPHIA PA.19101 [f[ .fQ,,

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November 19, 1975 ,gy g!/4,; , .

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~Lp Mr. Roger S. Boyd Acting Director Division of Reactor Licensing Office of Nuclear Reactor Regulations United States Nuclear Regulatory Conmission Wasnington, DC 20555 Dear Mr. Boyd;

Subject:

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

Region 1, Office of Inspection and Enforcement, United States Nuclear Regulatory Comissicn on November 10, 1975 Written notification was made to Mr. James P. O'Reilly, Office of Inspection and Enforcement, Region 1, United States Nuclear Regulatory Conmission on November 10, 1975 In accordance with Section 6 7 2.A of the Technical Specifications, Appendix A of DPR-44 f or Unit 2 Peach Bottorn Atomic Power station, the following report is being. subnli tted to the' 0irectorate of Reactor Licensing as an Abnormal Occurrence.

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Reference:

License Number DPR-44  ;

Technical Specification

Reference:

1.0.0.5 .

.-4 Report No.: 50-777-75-72 Report Date: November 19, 1975-Occurrence Date: November 9,1975 Facility: Peach Bottom Atomic Power Station R.D. 1, Delta, Pennsylvania 17314 Identification of Occurrence:

Crack in 3/4" vent line on RHR pipirg.

Conditions Prior to Occurrence:

Reactor shutdown and depressur ize'd.' Reactor head removed and "B" RHR loop in shutdown cooling mode.

Description of Occurrence:

While the "B" RHR loop was oper'ating in the shutdown cooling mode, a water leak was observed in the vicinity of the MO-2-10-1548 valve. The Icak was identified as a crack in a vent line adjacent to 133 M 4 the weld connecting the vent line to the process line. '

8401100174 751119 M PDR ADCCK 05000277 S PDR COPY SENT REGION}/ e

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Mr. Rog2r S. Boyd November 19, 1975 50q.77-75-72

,Page 2 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 throttic the M0-2-10-154B valve. This caused vibration which resulted in the crack.

Analysis of Occurrence:

The safety implications of this occurrence are minimal since the leakage did not impair the RHR system's ability to deliver design flow. Liquid effluent from the leak was safely contained to the invnediate area in the torus room. The leak was located external to the isolation valves.

Corrective Action:

Repairs have been completed in accordance with approved procedures. The Philadelphia Electric Company Engineering Department has reviewed the supports for this line and has recommended additional bracing. This bracing will be installed af ter approval by the organi-zation that performed the original design is obtained.

Very truly yours, Y-H. J. Cooney

/X L.Y Superintendent Generation Division - Nuclear  ;

cc: Mr. J, P. O'Reilly .

Director, Region 1 .

Of fice of Inspection and Enforcement U.S. Nuclear Regulatory Comission 631 Park Avenue King of Prussia, PA 19406 i -