NRC-94-4333, Documents 941027 Telcon Comments Re Proposed Rev to Control Room Habitability Section of SECY-94-084, Policy & Technical Issues Associated W/Regulatory Treatment of Nonsafety Sys in Passive Designs

Documents 941027 Telcon Comments Re Proposed Rev to Control Room Habitability Section of SECY-94-084, Policy & Technical Issues Associated W/Regulatory Treatment of Nonsafety Sys in Passive Designs

ML20078E660
Person / Time
Site:	05200003
Issue date:	10/31/1994
From:	Liparulo N WESTINGHOUSE ELECTRIC COMPANY, DIV OF CBS CORP.
To:	Borchardt R NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
FACA, NTD-NRC-94-4333, NUDOCS 9411150001
Download: ML20078E660 (2)

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Westinghouse Energy Systems Box 355 Electric Corporation Pittsburgt1 PennsyNania 15230 0355 j NTD-NRC-94-4333 l DCP/NRCO239 l Docket No.: STN-52-003 l October 31,1994 Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555 A'ITENTION: R. W. Borchardt

Subject:

Westinghouse comments on the proposed revision to Control Room Habitability section af SECY-94-084, " Policy and Technical Issues Associated with the Regulatory Treatment of Non-safety Systems in Passive Designs"

Reference:

12tter from R. W. Borchardt to N. J. Liparulo dated October 4,1994

Dear Mr. Borchardt:

This letter documents the October 27,1994 telecon between NRC (Jim Lyons, Tom Kenyon, David Tang, and Janak Raval) and Westinghouse (Dan McDermott, Mark Wills, and Andrea Sterdis). The purpose of the telecon was to provide Westinghouse comments on the contents of the referenced letter.

The comments are as follows:

The revised control room habitability discussion specifies a limitation of the required maximum leakage to less than 4 standard cubic feet per minute (SCFM) for the AP600 design. Although design calculations show that the control room envelope design should result in a leakage rate of less than 4 SCFM, a leakage rate of up to 20 SCFM is acceptable, provided the passive control room habitability system flow rate of 20 SCFM maintain a 1/8-inch water gauge differential pressure. Less specific references to determining leakage rates should also be revised to allow maintenance of pressure as an acceptable criteria. For example, the last bullet on page 3 of the revised SECY should be reworded as follows: "...nc tests would not need to last 72-hours, caly long enough to maintain pressurization or to measure leakage rate..."

The first full paragraph on page 2 of the revised SECY compares the volume change per hour for the AP600 control room envelope to that of the Standard Review Plan (SRP) and current plant designs. This comparison is not totally appropriate since the AP600 design isolates the control room envelope with far less volume exchanges because the normal HVAC is isolated.

This paragraph should be revised as we discussed.

It is unnecessary to perform a 72-hour contml room envelope pressurization test every ten years.

By assuring the functionality of the control room pressurization function and the adequacy of the bottled air supply every refueling outage, the function of the passive control room {

habitability system is verified.

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9411150001 941031 PDR ADOCK 05200003 ,

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NTD-NRC-94-4333 October 31,1994 The background discussion along with the revised SECY section state that a " COL licensee must demonstrate (1) the feasibility and capability of the safety-grade pressurization systems to satisfy GDC 19 criteria regarding control room habitability..." This statement should be revised since design certification of the passive control room habitability system will demonstrate the feasibility of the system to satisfy GDC 19.

The background information and tne revised SECY should be revised from "...the control room would be manned as usual and access to the control room would not be restricted during the test," to indicate that access to the control room need not be restricted. To perform the test, the COL holder may wish to limit control room ingress and egress.

On page 2 of the SECY revision, the statement pertaining to staff reservations relative to control room staffing limitations is inappropriate. The adequacy of control room staffing levels will be confirmed during design certification.

The first sentence on page 3 of the SECY revision (item 4) should be re-worded to state

" protection against the effects of accidental release of toxic gases and smoke outside or drawn inside the control room pressure boundary."

References to specific AP600 design valves, such as leakage rates and volume changes should be deleted from both the background discussion and the SECY revision.

The background discussion and SECY revision should be re-worded to allow for 24-month refueling outages. This can be accomplished by indicating that the tests would be performed at each refueling outage rather than specifying an interval, l

if you have any questions or require additional clarification, please contact Andrea Sterdis on (412) )

374-5292.

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4 Y N. J. Liparulo, Man,ager Nuclear Safety Regulatory and Licensitig Activities

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