ML20134P383

Submits Clarification of Design Basis Requirements at ONS for Permanently Installed Insulation in Response to NRC Bulletin 93-002, Debris Plugging of Emergency Core Cooling Suction Strainers

ML20134P383
Person / Time
Site:	Oconee
Issue date:	02/18/1997
From:	Hampton J DUKE POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
IEB-93-002, IEB-93-2, NUDOCS 9702250409
Download: ML20134P383 (3)

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^ Duke (bu'er Compcmy J Wllwrim (koneeNudecr5ae ' Vice fresicknt fil Bw109 (8&l}s333E13 Gilice Seneca SCTJ679 - (36tJ?833XIfhr DUKEPOWER February 18, 1997 U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555

Subject:

Duke Power Company Oconee Nuclear Site Docket Nos. 50-269, -270, -287 NRC Bulletin 93-02 Supplemental Information Debris Plugging of Emergency Core Cooling Suction Strainers As a result of recent reviews of insulation installed within containment, Oconee Nuclear Station (ONS) has been reviewing previously docketed correspondence on this issue. The purpose of this letter is to clarify the design basis requirements at ONS for permanently installed insulation.

In a letter dated June 9, 1993, Duke responded to NRC Bulletin 93-02, " Debris Plugging of Emergency Core Cooling Suction Strainers". NRC Bulletin 93-02 requested licensees to identify fibrous air filters or other temporary sources of fibrous material, not designed to withstand a loss of coolant accident (LOCA), which are installed or stored in containment, and to take the necessary measures to assure the functional capability of the Emergency Core Cooling System (ECCS).

In a letter dated July 1, 1993, the NRC responded to the June 9,.1993, Duke letter. In the July 1, 1993, NRC letter, it was stated that Oconee Nuclear Station (ONS) actions for NRC Bulletin 93-02 were considered complete based in part on the condition that " insulation installed inside containment either would not be transported to the emergency sump in the

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event of a LOCA or would be of small enough volume that the sump would not become clogged". '

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a The intent of the June 9, 1991, response was to describe how ONS met the specific requested actions of NRC Bulletin 93-02 regarding fibrous air filters and other temporary sources of fibrous material. There was no intent in this submittal to address or revise the design basis for use of already-existing permanent fibrous materials, or insulation generally, in containment. In the June 9, 1993, letter, Duke states that " Calculations OSC-3961 and OSC-3962 verify that insulation installed inside containment either will not be transported to the emergency sump in the event of a LOCA or will be of such volume that the sump screens will not become clogged". These calculations were performed to define requirements for permanent fibrous insulatior that may be installed in future applications within containraent.

Duke believes that referencing these calculations for the response to NRC Bulletin 93-02, although a proactive measure, went beyond the bulletin's request. We also believe that the reference to these calculations, although intended to describe our direction regarding future applications of fibrous material within containment, could be interpreted as a change to our design basis regarding  ;

already existing fibrous insulation in containment.

ONS has met and continues to meet the commitments made in response to NRC Bulletin 93-02, as stated in paragraphs 3, I 4, and 5 of the June 9, 1993, submittal. However, there was j no intent to expand the requested actions of this bulletin to include permanent insulation already installed in I containment which was dispositioned through Generic Letter 85-22 and USI A-43.

'If there are any questions or further information is needed, !

you may contact D. A. Nix at (864) 885-3634. l l

Very truly yours, J

. W. Hampton,

[/ Site Vice President l

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l NRC Document Control February 18, 1997 Page 3 xc: Mr. D. E. LaBarge, Project Manager l Office of Nuclear Reactor Regulation I U. S. Nuclear Regulatory Commission Washington, DC 20555 Mr. L. A. Reyes Regional Administrator, Region II U. S. Nuclear Regulatory Commission Mr. M. A. Scott ,

Senior NRC Resident Inspector Oconee Nuclear Station .

Mr. Max Botavia Bureau of Radiological Health SC Dept. of Health and Envionmental Cor#.rol 2600 Bull St.

Columbia, SC 29201 l

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