ML20085K186

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Provides Followup Info to 740325 Ltr Re Insp of Bergen-Paterson Hydraulic Shock Suppressors.During Refueling Outage,All 31 Drywell Snubbers Disassembled,Inspected & Overhauled Prior to Reinstallation
ML20085K186
Person / Time
Site: Dresden Constellation icon.png
Issue date: 05/15/1974
From: Stephenson B
COMMONWEALTH EDISON CO.
To: Oleary J
US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20085K183 List:
References
352-74, NUDOCS 8310200266
Download: ML20085K186 (1)


Text

. - - Comm erith Edison 3 one First anal P!a a. Chicago. Ilhnoi_s J Address Reply to: Post Ofhce Box 767 Chicago, Ilhnois 60690 Dresden Nuclear Power Station R. R. #1  !.

Morris, Illinois 60450 /, Q-4 BIE Ltr. #352-74 May 15, 1974 y 9 Mr. J. F. O'Ieary, Director Directorate of Licensing

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U. S. Atcr.ie Energy Ccenission Washington, D.C. 20545 Cyj, top;uw,g/

SUBJECT:

INSPECTICti Or EERGEI-PATERSCN HTDRAULIC SHOCK SUPPRESSORS AT DRESDEI NUCLEAR PCER STATIC:I, U?i1T #3 AEC DKT 50-249.

Reference:

letter frem lh . B. B. Stephenson to th . J. F. O'Ieary datcd March 25, 1974.

Dear Fr. 08Ieary:

This letter is to follcw-up the information reported in the letter referenced above.

During the current Unit 3 refueling outage, all thirty-cne (31) drywell snubbers were re=oved from the drywell. They were disassembled, inspected cM cverhauled prier to re-installation. All eristing sanh 4n the drywell snubbers were rencved and replaced with ethylene-propylene seals. All of the ethylene-propylene seals removed appeared to be in like new conditien. Scce of the existing untreated poly-urethane seals were gu==y and showed sete siens of deterioration. The snubbers reported in the referenced letter as inoperable or low en oil have been attributed to deterioration of the untreated poly-urethane seal material.

The torus snubbers were not overhauled because they are subjected to a much milder envirennent than those in the drywall and the existing seal caterial has been adequate.

The Grinnell snubbers in the turbine and isolation cordenser pipeways also were not overhauled. This was due to the unavailability of ethylene-propylene seal raterial. Overhaul of these snubbers was not considered necessary, since the existing seal caterial has been adequate.

Sincerely 3, O -

8310200266 740701

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