ML20003D588

Responds to Re Submittal of Plans,Schedules & Design Descriptions of 10CFR 50,App R,Mod for Fire Protection.Forwards Design Description of Alternate Svc Water Capability

ML20003D588
Person / Time
Site:	Davis Besse
Issue date:	03/19/1981
From:	Crouse R TOLEDO EDISON CO.
To:	Stolz J Office of Nuclear Reactor Regulation
References
697, TAC-52156, NUDOCS 8103270707
Download: ML20003D588 (6)

Text

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r TOLEDO

%mm EDISON Docket No. 50-346 A<*.ic P Cacuse Lic.ense No. NPF-3 CU" Serial No. 697 m9esm March 19, 1981

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[M[ Wh Director of Nuclear Reactor Regulation Attention:

Mr. John F. Stolz j.)

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Operating Reactor Branch No. 4 Gj Ygh"# /[j Division of Operating Reactors United States Nuclear Regulatory Commission

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Dear Mr. Stolz:

This submittal is in response to your letter dated February 20, 1981 (Log No. 664), concerning the submittal of plans, schedules and design descriptions of 10CFR50 Appendix R, modification for fire protection at the Davis-Besse Nuclear Power Station Unit 1 (DB-1).

Under 10CFR50.48(b), DB-1 is an operating nuclear power plant licensed prior to January 1, 1979 that received a NRC review and safety evaluation report satisfying Appendix A to Branch Iechnical Position 9.5-1.

A NRC letter of November 24, 1980 (Log No. 636) verified there were no "open items" remaining from that review. The post modification design will meet the requirements of our safety evaluation report and Section III.G.,

III.J and III.0 of Appendix R to 10CFR50.

Currently all fire protection system modifications have been completed except the alternate to the service water system (SWS) identified in Volume I, Section 4, Paragraph Fil and Volume II Response to NRC Ques-tion No. 11 in the DB-1 Fire Protection Safety Evaluation Report. The previous schedule had reflected a mid-1984 completion of this alternate capability.

In response to 10CFR50, Appendix R, we have revised that schedule.

It is our current intention to provide this alternate prior to startup after the next refueling outage. This constitutes our next planned outage and is therefore consistent with Appendix R.

The refuel-ing outage is currently scheduled to begin the end of February 1982.

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II THE TCLEDO EDISON COMPANY EDISON PLAZA 300 MAO SON AVENUE TOLEDO. OHIO 43652 w

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. The design description of the alternate service water capability is attached for your review. This includes discussions of the mechanical, ventilation and electrical design modifications.

This submittal is considered responsive to both Appendix R and your letter of February 20, 1981. If you have any questions concerning this effort you are requested to contact us Unmediately. Due to the large magnitude of the plant modification and the shortness of the schedule we are proceeding with its implementation.

Yours very truly,.

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DB-1 Resident Inspector

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DESIGN DESCRIPTION FOR THE ALTERNATE SERVICE WATER CAPABILITY j

The basic approach to providing an alternate service water capability at DB-1 is to modify or replace an existing dilution pump to supply water to the service water system (SWS) without utilizing equipment located in the same fire area as the service water system (SWS) pumps and will be powered independent from off-site supplies.

Specifics of the modification are discussed below and are compared between Figure 1 (current design) and Figure 2 (post modification design).

MECHANICAL DESCRIPTION The existing dilution pump P180 (10,250 gpm @ 70 feet) located in the intake structure is being modified to a pump that duplicates the existing service water pump capacity (10,250 gpm 0 160 feet). This new pump will serve as the dilution pump during normal plant operation. Following a postulated fire in the service water pump room this pump will also provide adequate flow to the SWS without utilizing equipment common to the affected fire area.

A piping sketch for the new pump and system arrangement is provided as Figure 2 attached. A branch line is provided to tie into the existing service water system. A strainer is being provided to protect the service water system components. The associated valving is manual consistent with discussions in Volume II response to NRC Question No. 11 of the Fire Hazards Analysis Report for DB-1.

HVAC DESIGN Assured fire separation necessitates some modifications to the intake structure interior walls and requires changes to the existing EVAC systems.

Figure 2 attached shows a plan view of the intake structure after the modification. The walls shown along Column IB and ID separate the dilution pump from the service water pumps and valves respectively.

These walls are being upgraded to a three hour fire rating. This requires sealing the existing ventilation openings in the column line 1B wall.

This modification eliminates the natural convective air flow path through thr:e openings and out a roof top penthouse currently relied on during loss of function of the non-safety related fans located on column line ID.

To compensate for.the loss of convective air flow, ventilation systems in both the Screen House and the service water pump room will be modified.

In the screen house:

, a.

A new roof top exhaust fan will be added.

b.

The new fan will be able to be supplied by on-site power.

For the se vice water pump roem:

a.

existing exhaust fans will be upgraded to safety related including seismic design, power supplies and control.

b.

Tornado missile protection will be provided.

ELECTRICAL DESIGN The modified dilution pump and its asse:iated ventilation system will operate following a loss of off-site power. All associated equipment and cables will be located outside the service water pump room. This requires some conduit rerouting. The new roof exhaust fan for the screen house area will be supplied'from essential MCC E12C. This is located in the diesel fire pump room. The modified dilution pump will remain powered from 4160V, Bus C2.

Because the same bus powers the station lighting system, DB-1 Emergency Procedure No. 1202.02, " Station Blackout", provides for manual loading of this bus onto Diesel Generator No. I'from the control room.

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