ML20069H089

Forwards Response to NRC 940529 RAI on NRC Bulletin 93-002, Debris Plugging of Emergency Core Cooling Suction Strainers

ML20069H089
Person / Time
Site:	Catawba
Issue date:	06/02/1994
From:	Rehn D DUKE POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
IEB-93-002, IEB-93-2, TAC-M86545, TAC-M86546, NUDOCS 9406100305
Download: ML20069H089 (3)

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' , Catou ba Nutlear Generatson Deponment Vice President 4800 Concord Road (303)R313205 Office lhrk..SC29745 (803}S313426 Fax DUKEPOWER June 2,1994 U.S. Nuclear Regulatory Conunission ATTN: Document Control Desk Washington, D.C. 20555

Subject:

Catawba Nuclear Station, Units 1 and 2 Docket Nos. 50-413 and 50-414 Request for AdditionalInformation on NRC Bulletin 93-02 (Debris Plugging of Emergency Core Cooling Suction Stminers)

TAC Nos. M86545 and M86546 Gentlemen:

In response to your request for additional infonnation of May 29,1994, please find attached our reply to the questions provided.

Should you have any questions pertaining to this material, please call L.J. Rudy at (803) 831-3084.

Very tmly yoy s, W, v

.a h y D.L. Rehn UR/s .

Attachment xc: S.D. Ebneter, Regional Administrator Region II R.J. Freudenberger, Senior Resident Inspector R.E. Martin, Senior Project Manager l 1

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, OUESTIONS FOR CATAWBA FOR FINAL SER

1. State the purpose of each system, or is it the same as for the Lower Containment Filter Cleanup (LCFC) system? Is the LCFC system the same as the CACFU system? The l pages sent with the May 9.1994 letter do not discuss the UCVU, IIRVU, or CACFU. l It discusses cooling units only with the exception of the LCFC.

2. Provide a statement as to the hardship caused by not being allowed to retain the HEPA and Pre-filters in the systems. If only the HEPA filters were allowed to be reinstalled,  ;

would this meet the station's needs?

3. Can containment sprays directly impinge on CACFU HEPA filters?

4. What is the surface area of the sump screens?

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NRC Bulletin 93-02 Supplemental Response to Questions Received 5/29/94

1) There are three (3) subsystems in containment at CNS that have ventilation equipment containing fiberous media filters. The filter containing equipment in each of these subsystems are (1) the Upper Containment Ventilation Units (UCVUs), (2) the incore instrumentation Room Ventilation Units (llRVUs) and (3) the Containment Auxiliary Carbon Filter Units (CACFUs). A forth ventilation subsystem is located in containment but this system does not contain any filter material. This subsystem is the Lower Containment Ventilation System and it contains the Lower Containment Ventilation Units (LCVUs). The purpose of each of these units is described below.

UCVUs - These are air handling units consisting of metal housings, fans, cooling coils, and filter racks. The purpose of these units is to provide cooling to the Upper Containment.

IIRVUs - These are air handling units consisting of metal housings, fans, cooling coils, and filter racks. The purpose of these units is to provide cooling to the incore instrumentation Rooms. -

CACFUs - These are filter units consisting of metal housings, fans, prefilter racks, HEPA filter racks and carbon adsorbers. The purpose of these filter units is to reduce the radioactivity level in the lower containment prior to personal entry.

LCVUs - These are air handling units consisting of metal housings, fans, cooling coils, and fitter racks. The purpose of these units is to provide cooling to the Lower Containment. CNS does not install filters in these units.

2) A more frequent change out of the carbon filter material in the CACFUs will result if the prefilters and HEPA fitters are not installed. Having the HEPA filters installed without prefilters will cause the HEPA filters to clog f aster thus requiring them to be changed out more frequently.

The station's needs can be meet by only having the HEPA filters, and not the prefilters, installed in the CACFUs. .

3) The containment sprays can not directly impinge on the HEPA filters in the CACFUs.

4) The surface area of the sump screens is approximately 135 ft2 9302sup1 i

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