ML20086L517

AO 74-11:on 740318,main Steam Line Drain Valve MO-2-77 Failed to Close.Caused by Malfunction of Group I Isolation Circuitry.Valve Operated Correctly During Group I Logic Sys Functional Surveillance Test

ML20086L517
Person / Time
Site:	Peach Bottom
Issue date:	03/26/1974
From:	Cooney M PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	Giambusso A US ATOMIC ENERGY COMMISSION (AEC)
References
AO-74-11, NUDOCS 8402080281
Download: ML20086L517 (2)

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U PHILADELPHIA ELECTRIC COMPANY ,?

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~WW Mr. A. Giambusso Deputy Director of Reactor Projects United Sta tes Atomic Energy Conrnission Directorate of Licensing Washington, D.C. 20545

Subject:

Abnormal Occurrence The following occurrence was reported to Mr. D. Caphton, A.E.C. Region I Regulatory Opera tions Office on March 19, 1974 Written notification was made to Mr. James P. O'Reilly, Region I Regulatory Operations Office on March 19, 1974. In accordance with Section 6.7.2.A of the Technical Specifications, Appendix A of DPR-44 for Unit 2 Peach Bottom Atomic Power Station, the following report is being submitted to the Directorate of Licensing as an Abnormal Occurrence.

Reference:

License Number DPR-44, Amendment No.1 Technical Specification Table 3.7.4 Report No.: 50-277-74-11 Report Date: Ma rch 19, 1974 Occurrence Date: March 18, 1974 '

Faci li ty: Peach Bottom Atomic Power Station - Unit 2 R.D. 1, Delta, Pennsylvania 17314 Identi fication of Occurrence:

Following a Group I isolation caused by instrument sur-veillance testing, it was determined that the main steam line drain valve M0-2-77 failed to close.

Conditions Prior to Occurrence:

Plant stable at approximately 48% power. -

P Description of Occurrence: /

3 During instrument surveillance testing a Group I isolation

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l Mr. A. Gitmbusso March 26, 1974 Page 2

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line drain valve M0-2-77 failed to close as required by Group I isolation. The valve was manually closed by the operator immediately following the occurrence.

Designation of Apparent Cause of Occurrence:

Since the valve was manually operable immediately af ter this

occurrence, the Group I isolation circuitry apparently malfunctioned and did not request a valve closure.

Analysis of Occurrence:

This valve, MO-2-77, is in series with another isolation valve M0-2-74, which did close correctly as a result of the isolation.

Because the line was isolated, there was no safety implicatio.,.

Corrective Action:

, The valve was operated numerous times following this occur-rence from the test pushbutton in the automatic isolation circuitry.

The valve also operated correctly during the Group I logic system functional surveillance test which was performed to ensure proper relay

, and valve operation. No specific cause for the failure of this valve to close on the Group I isolation was identified as a result of this i nves ti ga ti on.

Very truly yours, i 1, i

/ / /l'f . ay/

M.,J. Cooney Asst. Gent. Supt.

Generation Division cc: Mr. J. P. O' Rei l ly Director, Region I United States Atomic Energy Commiasion 631 Park Avenue King of Prussia, PA 19406 -

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