ML20086K587

AOs 74-55 for Unit 2 & 74-32 for Unit 3:on 741127,four Excess Flow Check Valve Bypass Valves Discovered in Open Position.Caused by Improper Procedural Control of Bypass Valve for Excess Flow Check Valve.Valves Closed

ML20086K587
Person / Time
Site:	Peach Bottom
Issue date:	12/07/1974
From:	Cooney M PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	Giambusso A US ATOMIC ENERGY COMMISSION (AEC)
References
AO-74-32, AO-74-55, NUDOCS 8401270307
Download: ML20086K587 (2)

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- PHILADELPHIA ELECTRIC COMPANY

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December 7, 1974 'f ' .' O 1

Mr. A. Giambusso Deputy Director of Reactor Projects

. United States Atomic Energy Commission Directorate of Licensing Washington, D.C. 20545 Dear Mr. Giambussor

Subject:

Abnormal Occurrence The following occurrence was reported to Mr. Walt Baunack, A.E.C. Region 1 Regulatory Opera tions Of fice on November 27, 1974 Written noti fication was made to Mr. James P. O'Reilly, Region 1 Reg-ulatory Operations Office on November 29, 1974. In accordance with Section 6.7.2. A of the Technica l Speci fications, Appendix A of DPR-44 for Unit 2 and DPR-56 fcr Unit 3 Peach Bottom Atomic Power S ta ti on, the following report is being submitted to the Directorate of Licensing as an Abnormal Occurrence.

Reference:

License Number DPR-44 and 50-278,74-32 Technical Speci fication Paragraph 3 7.D.2 Report No.: 50-277-74-55 and 50-278-74-32 Report Dato: December 7, 1974 Occurrence Date November 27, 1974 Faci li ty: Peach Bottom Atomic Power Station Delta, Pennsylvania 17314 Identi fica tion of Occurrence:

Discovery of four excess flow check valve bypass valves in the open position.

Condi tiens Prior to Occurrence:

Unit 2 at approximately 100X and Unit 3 at approximately 50%

power.

Description of Occurrence:

During the investigation of an instrument problem, seve ra l instrument sensing lines were traced in an ef tort to identi fy possible leaks. During this investigation, the bypass valves of four excess flow check valvos associa ted wi th Uni t 3 instrumentation, were found in the open posi Son. q r)}; 71 8401270307 741207 j DR ADOCK 05000 COPY bW WOR ,

. O O A Mr. A. Giambusso December 7, 1974 .

Page 2 Designation of Apparent Cause of Occurrence:

Improper procedural control of bypass valves for excess flow check valves.

Analysis of Occurrence:

The instrument sensing lines are provided with a restricting orifice inside the drywell, a manual shutoff valve outside the drywell, and an excess flow r. hock valve immediately downstream of the shutoff valve outside the drywell. Each excess flow check valve has a bypass valve which is opened during reactor vessel hydrostatic testing, integrated Icak rate testing, and local leak rate testing. The bypass valves on the excess flow check valves should normally be closed during reactor power operation. The instrument sensing lines are small diameter piping which also tend to limit flow. Total Icakage on a ruptured instrument line would be limi ted by the upstream orifice wi th the excess flow check valve disabled. Since Icakage is limited by another in-line device and no piping failures have occurred, the safety implications associated with this event are minimal.

_ Corrective Actions i

j Af ter noting the above 4 valves in an open position, all ex-cess flow check valves in both Unit 2 and Unit 3 were checked. This 1

inspection revealed two additional bypass valves on Unit 2 and two l additional bypass valves on Unit 3 in the open position. All other valves were found in the closed posi tion. The valves which were found i open were immediately closed. -

The applicabic test procedures have been reviewed and revised to include appropriate steps to ve.-ify that the bypass valves of the excess flow check valves have been returned to the closed pos{ tion af ter completion of the test. '

I Failure Data:

Abnormal Occurrence Report No. 50-277-74-36 and 50-278-74-10.

I Very truly yours, n(

// M.j, C - ; n a ,)-

J. Cooney l

Asst. Gent. Supt.

l Genera tion Division

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e cc: Mr. J. P. O'Ref ily l Director, Region 1  ;

Uni ted S tates Atomic Energy Cornission 631 Park Avenue  !

King of Prussia, PA 19406 i

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