ML20086K561

AO 75-2:on 750115,leakage Found on Inboard Main Steam Line Sample Isolation Valve.Caused by Local Leak Rate Test Pressure Under Seat of AO-316.Compression Spring Adjusted

ML20086K561
Person / Time
Site:	Peach Bottom
Issue date:	01/25/1975
From:	Meyer R PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	Giambusso A Office of Nuclear Reactor Regulation
Shared Package
ML20086K564	List: ML20086K561 ML20086K566
References
AO-75-2, NUDOCS 8401270256
Download: ML20086K561 (2)

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PHILADELPHIA ELECTRIC COMPANY - sG O, . .

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January 25, 1975

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Mr. A. Giambusso Deputy Director of Reactor Projects.

United States Atomic Energy Commission Directorate of Licensing Washington, DC 20545 J

Subject:

Abnormal Occurrence

• The following occurrence was reported to Mr. Don Caphton, A.E.C. Region 1 Regulatory Operations Office on January 16, 1975 Written notification was made to Mr. James P. O'Reilly, Region 1 Regu-latory Operations Office on January 16, 1975 In accordance with Section 6.7 2.A of the Technical Specifications, Appendix A of DPR-44 fer Ur.it 2 Pecch Dettcm Atomk Ne. Giotivo, Lim Tuliowing report is _

being submitted to the Directorate of Licent.ing as an Abnormal Occu'r rence.

Reference:

License Number DPR-44 Technical Specification

Reference:

4 7.A.2.f

. Report No.: 50-277-75-2 Report Date: January 25, 1975 Occurrence'Date: January 15, 1975 Facility: Peach Bottom Atomic Power Station R. D. 1, Delta, Pennsylvania 17314 Identification of Occurrence:

Leaking Unit 2 inboard main steam line sample isolation valve.

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The reactor was shutdown and a maintenance outsge was in prog-ress.

-Description of Occurrence:

As a result of performing a local leak rate test, it was dis-covered that the . inboard main steam line sample isolation valve did not appear-to seal tightly.' The outboard isolation valve was closed.

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Hr. A. Giambusso bs' January 25, 1975 Page 2 Des'ignation of Apparent Cause of Occurrence:

Investigation revealed that local Icak rate test pressure under the seat of A0-316 causet the valve to open and appear to leak excessively.

Analysis of Occurrence:

Normally, reactor pressure is on top of the valve disc which will cause the valve to seat more tightly. Since it was not necessary to maintain the valve internals, it is very probabic that valve Icakage would have been ecceptable under operating conditions, since the Icak rate measured during a subsequent Icak test was found acceptabic.

The other isolation valve in this line was verified to seal properly and was left in the closed position. For these reasons, the occurrence has minimal safety implications.

Corrective Action:

The compression spring which closes the valve was adjusted slightly to provide more positive valve closure. Since the valve re-quires air to open, actuator air pressure was increased slightly to compensate for the spring adjustment.

Failure Data:

Previous f ailures of this type were reported as Abnormal Occurrence Reports 50-278-74-15 and 50-278-75-1.

Very truly yours, f &Oc lb(

R . D. Heyer /

General Superintendent

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Generation Division ec: Mr. J. P. O'Reilly Director, Region i Uni ted States At omic Energy Commi ssion 631 Park Avenue King of Prussia, PA 19406

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