ML20084F954

Responds to Requesting Periodic Insp of Hydraulic Suppressors.Insp on 731009-12 of Snubber Installation Revealed Accumulator on Snubber MS-148 Defective. Accumulator Replaced

ML20084F954
Person / Time
Site:	Ginna
Issue date:	10/26/1973
From:	Amish K ROCHESTER GAS & ELECTRIC CORP.
To:	Skovholt D US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20084F681	List: ML20084F679 ML20084F687 ML20084F700 ML20084F711 ML20084F720 ML20084F726 ML20084F813 ML20084F842 ML20084F856 ML20084F871 ML20084F886 ML20084F900 ML20084F911 ML20084F918 ML20084F929 ML20084F938 ML20084F945 ML20084F954
References
NUDOCS 8304210343
Download: ML20084F954 (1)

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ROCHESTER GAS AND ELECTRIC CORPORATION e 89 EAST AVENUE, ROCHESTER, N.Y.14649

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October 26, 1973

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Mr. Donald J. Skovholt 8

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Assistant Director for Operating Reactors "l

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Directorate of Licensing Dai,,

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Subject:

Inspection of Hydraulic Shock Suppressors (Snubbers)

M ~[T.d R. E. Ginna Nuclear Power Plant, Unit No.1 Docket No. 50-244

Dear Mr. Skovholt:

This is in response to your letter of October 1,1973 in which you requested the periodic inspection of hydraulic suppressors (snubbers).

Ginna Station has the following units installed:

Safeguard Non-Safeguard System Sys' tem Total o

Bergen-Paterson 22 4

26 Grinnel 8

5 13 Anker-Holth 16 0

16 (Steam Generators)

An inspection was made during the period October 9-12, 1973 of the snubber installation on both safeguard and non-safeguard systems. All units were considered operable, but the Bergen-Paterson accumulator on snubber MS-148, located outside the intermediate building on the "B" main steam line, was found to have a defective accumulator assembly. This installation has a remote accumulator mounted vertically about ten feet above the snubber.

During the inspection, fluid was added to the accumulator and the piston on the accumulator would not move. This accumulator was replaced with a rebuilt accumulator with polyurethane "O" rings and pisto'n seal.

Upon inspection of the removed accumulator, the spring was found to be broken and the piston had seized in the cylinder. The space under the piston still contained hydraulic fluid. It is believed that the piston had seized due l

to moisture entering the space above the piston through the indicator opening.

Plastic covers have now been installed over all outside accumulators to prevent entry of moisture.

Subsequent to the above inspection, on October 22 when the station was not operational, the Bergen-Paterson accumulator was removed from snubber FW-30 8304210343 751223

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ROCHE57ER GAS AND CTRIC CORP.

SHEET NO. 2 October 26/1973 Darc To Mr. Donald J. Skovholt to replace a seal that appeared to be leaking. Inspection in the shop found a worn piston seal and broken piston spring. The space under the piston still contained hydraulic fluid. New polyurethane "O" rings and piston seal are being installed, the spring replaced and the accumulator reinstalled.

Fro >n inspection of the two accumulators with broken springs, it appears there was still sufficient spring force to apply a positive head of hydraulic fluid pressure to ensure proper operation of the snubber. All accumulators have been tested to ensure that the pistons are free and hydraulic fluid is in the cylinders. We have discussed with Bergen-Paterson the spring failures and requested that information and recommendations for corrective action be provided as soon as possible.

Very truly yours, eith W. Amish xc: Mr. J. P. O'Reilly 8

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