ML20086J358

AO 74-13:on 741015,HPCI Gland Seal Condenser Head Gasket Found Leaking.Caused by High Spots in Area Between Internal Baffles & Tube Sheet.Plant Shut Down.High Spots Removed.New Head Gasket Installed & Head Properly Tightened

ML20086J358
Person / Time
Site:	Peach Bottom
Issue date:	10/25/1974
From:	Cooney M PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	Giambusso A US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20086J362	List: ML20086J358 ML20086J363
References
AO-74-13, NUDOCS 8401230595
Download: ML20086J358 (3)

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October 25, 1974 SC-W7tB Mr. A. Giambusso Deputy Director of Reactor Projects United States Atomic Energy Commission Directorate of Licensing Washington, D.C. 20545

Subject:

Abnormal Occurrence The following occurrence was reported to Mr. Walt Baunack, A.E.C. Region 1 Regulatory Operations Office on October 15, 1974 Written notification was made to Mr. James P. O'Reilly, Region 1 Regulatory Operations Office on October 15, 1974. In accordance with Section 6.7.2.A of the Technical Specifications, Appendix A of DPR-56 for Unit 3 Peach Bottom Atomic Power Station, the following report is being submitted to the Directorate of Licensing as an Abnormal Occurrence.

Reference:

License Number DPR-56 Technical Specification Reference 3.5.C.1 Report No. : 50-278-74-13 Report Date: October 25, 1974 Occurrence Date: October 15,' 1974 Facility: Peach Bottom' Atomic Power Station R.D. 1, Delta, Pennsylvania 17314 Identification of Occurrence:

HPCI gland seal condenser head gasket leak.

Conditions Prior to Occurrence:

Reactor at approximately 35% power. Electrical power output 327 MW.

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Description of Occurrence:

During a HPCI injection to the reactor vessel performed as part of the startup test program, a leak was noted on the HPCI gland seal condenser head gasket. The vessel injection test was successful. However, to reduce leakage of water from the condensate tank to the HPCI room, the HPCI pump had to be isolated, thereby making the HPCI system inoperable.

Designation of Apparent Cause of Occurrence:

The head gasket leak is believed to have been caused by high spots in the area between the internal baffles and the tube sheet. These high spots prevented proper compression of the head gasket.

Analysis of Occurrence:

Since the unit was only at 35% power and had only operated at a maximum 60% power for a short time, decay heat load was significantly below the equilibrium full power value. With both the HPCI and one RHR pump inoperable, sufficient emergency cooling systems were available. This occurrence has minimal safety significance.

Corrective Action:

With the HPCI inoperable and one RHR pump out of service, the Technical Specifications require a plant shutdown within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

The plant was therefore shutdown to a cold shutdown within the allowable time interval.

The high spots noted following disnantling of the heat exchanger head were removed to produce an interference-free sealing surface. A new head gasket was installed and the head properly tightened. During the reactor startup on October 16, 1974 the HPCI surveillance test required by Technical Specifications 4.5.C.1 (b), (c), (d) and (e) were satisfactorily performed. -During both periods of HPCI operation at 150 psig and rated reactor pressure, inspections of the gasket revealed no leaks, A'HPCI vessel in-jection test was also successfully repeated on October 18, 1974 Failure Data:

During the Unit 2 startup program, minor leakage on the s

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Mr. A. Giamb o.

October 25, 1974

• Page 3 I

Failure Data: (con't) same gland seal condenser head gasket was noted and corrected on serveral occasion. Investigation of these problems also identified the interference problem between the internal baffle and the tube sheet. Correction of this problem on Unit 2 has apparently resolved the leakage.

Very truly yours, b

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M. . Cooney As 't Gen'l uperintendent Generation Division cc: Mr. J. P. O'Reilly Director, Region 1 United States Atomic Energy Commission Directorate of Licensing Washington, DC 20545 4

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