ML20065T730

Final Deficiency Rept Re Pipe Support Snubber Design. Initially Reported on 820527.Approved Snubber Reduction Program Will Identify Snubbers Unnecessary from Thermal Expansion Viewpoint.Completion Expected Prior to Fuel Load

ML20065T730
Person / Time
Site:	Fermi
Issue date:	10/22/1982
From:	Wells D DETROIT EDISON CO.
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
10CFR-050.55E, 10CFR-50.55E, EF2-59401, NUDOCS 8211020668
Download: ML20065T730 (2)

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Donald A. Wells gg [NM[tAf^"""

Edison EEsm-October 22, 1982 EF2-59401 Mr. Janes G. Keppler, Regional Administrator Region III U.S. Nuclear Regulatory Cmmission 799 Roosevelt Road Glen Ellyn, Illinois 60137-

Subject:

Final Report of 10Cm50.55(c) Item on Pipe Support Snubber Design Deficiency (#69)

Dear Mr. Keppler:

This is Detroit Edison's final report on the pipe support snubber design deficiency. This problem was originally reported to Mr. H. Wescott of NRC Region III by Detroit Edison's Mr. H.A. Walker, Supervisor-Construction Quality Assurance, on May 27, 1982.

During an NRC inspection, Mr. I.T. Yin of the NRC noted a number of locations where snubbers were to be installed where their functional ability would be impaired. In sme instances, the movenent was not sufficient to allow the snubber to lock-up, transferring the snubber load to adja nt rigid supports causing possible over-stress. This is a potential safety problem.

A stop work order was issued on May 25, 1982, for all snubber related construc-tion activities. Based on discussions and agreenents between Mr. Yin and nenbers of Edison's Engimering staff, the stop work order would not be lifted until a formal " Snubber Reduction Program" was issued for Fermi 2 by Edison, and that program was reviewed and accepted by Mr. Yin. On June 4, 1982, Detroit Edison subnitted a proposed " Snubber Reduction Program" to Mr. Janes G. Keppler.

Based upon a Jum 7,1982, telephone conversation between Mr. Yin and our Mr. J.G. Casiglia, Edison was inforned that Mr. Yin had reviewed the proposed program and found it acceptable. On June 8,1982, Detroit Edison subnitted a final record copy of the " Snubber Reduction Program" to Mr. Keppler.

With the acceptance of the " Snubber Reduction Program", Edison proceeded to lift the stop work order and resune snubber construction in an orderly arri controlled fashion. To date, the major activities relative to the implenenta-tion of this program consist of the following:

o In accordance with the " Snubber Reduction Program", on June 9,1982, the stop work order was lifted for the majority of the snubbers on 2 inch and smaller ASME Class 2 and 3 lims that were analyzed by gemric nethods.

8211020668 821022 o PDR ADOCK 05000341 /

S PDR OCT 2 51982

,o Mr. James G. Keppler, Regional AcLninistrator October 22, 1982 Page 'IWo EF2-59401 o On July 12, 1982, the stop work order was lifted for approximately 160 snubbers on large bore piping systems which nust be installed as per the criteria of the " Snubber Reduction Programs".

o In order to cmplement construction activities, snubbers located near the RHR Punps and the Core Spray Punps were evaluated in accordance with the " Snubber Reduction Program". As a result of that evaluation, 28 snubbers are scheduled tc, be replaced with rigid struts and 4 snubbers will be cancelled, o Inplementation of the " Snubber Reduction Program" is continuing at Edison. The necessary activities are being coordinated with construc-tion activities and Edison's Piping Stress Reconciliation Programs.

In accordance with Mr. Yin's request, Edison will provide a cmparison between the number of all suspension capomnts originally required and the number actually required after the snubber reduction program is empleted. This data will be included in the documentation that will be forwarded to the NRC when the program is empleted.

Project Design is confident that the " Snubber Reduction Program" currently being carried out will identify any snubbers that are unnecessary fran a thermal expansion viewpoint and will. also resolve the issue of dynamic actua-tion of snubbers. Project Design estimates that full empliance with the

" Snubber Reduction Program" will be achieved prior to fuel load.

If you have questions concerning this matter, please contact Mr. G.M. Trahey, Assistant Director-Project Quality Assurance.

Very truly yours, DAW /DF/cp cc: Mr. Richard DeYoung, Director Office of Inspection and Enforcement U.S. Nuclear Regulatory Cmmission -

Washington, D.C. 20555 l Mr. Bruce Little, Senior Resident Inspector U.S. Nuclear Regulatory Cmmission 6450 North Dixie Highway Newport, Michigan 48166

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