ML20084J089

Supplementary AO: Beginning 740112,during Plant Shutdown, Hydraulic Shock & Sway Arrestor Insp Found 30 Affected Snubbers.Surveillance Program Outlined on 731207 Will Continue Until Satisfactory Solution Is Found

ML20084J089
Person / Time
Site:	Oyster Creek
Issue date:	04/02/1974
From:	Ross D JERSEY CENTRAL POWER & LIGHT CO.
To:	Giambusso A US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20084J091	List: ML20084J089 ML20084J094 ML20084J098
References
NUDOCS 8305100068
Download: ML20084J089 (2)

Text

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.ersey Central Power & Light Company lk['M cv QQ9 MADISON AVENUE AT PUNCH BOWL ROAD

• MORRISTOWN, N.J.079GO

• 201-539-6f11 o un a r=

/[,yjj, Poc utm::e3 corcarat en cenerai D b7E M April 2, 1974 Mr. A. Giambusso

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Deputy Director for Reactor Projects i'

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United States Atomic Energy Commission Washington, D. C. 20545 0,.

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Dear Mr. Giambusso:

VC'.

Subject:

Oyster Crcok Station Docket No. 50-219 Hydraulic Shock and Sway Arrestor Inspection -

January 1974 The purpose of this letter is to forward to you supplementary in-formation regarding the seals of five " failed" hydraulic shock and sway arrestors (snubbers) found in the drywell during the plant shutdown which began on January 12, 1974. The initial report on the January inspection of the snubbers in the drywell was forwarded by letter dated February 19, 1974.

A visual inspection of the seals removed from the five failed snubbers indicated that several types of material were used in each unit. To determine which of the materials had failed, the seals were sent to the GPU System Lcboratory for material identification analyses using infrared scans and microscopic examinations. The results of the naterial analysis can be sunnari::ed as follows:

1.

Only three seals in cach snubber werc of the recommended polyethylene-propylene (PEP) material.

2.

None of the PEP seals showed any sign of failure.

3.

Two types of polvurethane were used in the failed snubbers.

These were the millabic gun and the cast polyurethane.

4.

One fiber seal was also discovered in two of the snubbers.

Both of these units were of an old seri.es which could not be rebuilt completely. The fiber seals had probably never been changed out at the tine the snubbers were rebuilt or they were cut from new unidentified gasket material.

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One other seal used in the two old series snubbers could not be identified. The material is believed to be teflon.

6.

The seals which, because of their physical characteristics, had visually appeared to be failed before the laboratory analysis are now identified to be millable gum polyurethane.

We believe the results of the laboratory analyses provide further evidence that ethylene-propylene is the material best suited for replacement seals in the hydraulic snubbers located in the drywell and in the reactor building.

Enclosed are forty copics of this submittal.

Very truly yours,

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'jfV,%Lh Donald A. Ross Manager, Nuclear Generating Stations es Enclosures cc:

Mr. J. P. O'Reilly, Director Directorate of Regulatory Operations, Region I

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