ML19289G299
| ML19289G299 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 08/02/1979 |
| From: | Janecek R COMMONWEALTH EDISON CO. |
| To: | Nowicki S Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 7908210284 | |
| Download: ML19289G299 (5) | |
Text
f Commonwealth Edison One First National Plaza Chicago. filinois Address Reply to Post Office Box 767 Chicago, tilinois 60690 August 2, 1979 Mr.
S. J. Nowicki Project Manager U.S. Nuclear Regulatory Commission Washington, D.C.
20555
Subject:
Dresden Station Unit 1 Fire Protection Modifications Additional Information NRC Docket No. 50-10
Dear Mr. Nowicki:
Enclosed for your review is additional information requested previously during telephone conversations and meetings between the NRC Staff and Commonwealth Edison Co.
The information pertains to the fire water system feeds and exposed structural steel reviews currently in progress.
Please address any additional questions concerning this matter to this office.
Very truly yours, Robert F. Janecek Nuclear Licensing Administrator Boiling Water Reactors enclosure
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Fire Water System Feeds The NRC requested that we have separate feeds for the hose stations from the feeds for the fixed suppression i
systens in the Unit 1 North Auxiliary Bay, the post incident /
I core spray pump area and the cable passageway.
The North Auxiliary Bay may be reached by two hose stations (f-21 and F-22).
These are noted as item 74 and 76 on M-341.
It is protected by a wet pipe system shown as item 126 on the drawing.
Both hose stations and the fixed suppression are separated on the header by isolation valves.
The post incident / core spray area may be reached by hose station F-40 shown as item 67 on M-341.
It is protected by a wet pipe system shown on item 120 on the drawing.
The j
hose station and fixed suppression system are separated on the header by an isolation valve.
The cable passageway at present is covered by hose station F-29 shown as item 79 on M-341.
It is covered by a pre-action water suppression system.
Item numbers on M-341 have not yet been assigned for the passageway but tie-in points are marked.
In addition a hose station is being added at each tie-in point for the fixed suppression system.
The tie-in points are separated by an isolation valve in the main header.
A reel of hose is to be added at approximately the halfway point in the tunnel.
If either section of the hesder had to be taken out of service two out of the three hose stations would remain in service and if additional hose were needed could be connnected to the reel of hose located in the tunnel.
This gives full coverage of the tunnel manually at all times.
(See attached sketch).
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Exposed Structural Steel The NRC requested that the exposed structural steel in the North Auxiliary Bay above the large concentration of cables in the area be provided with flame retardant coatings.
The combustible material in this area is made up of 308 feet 3 cable insulation and as listed in the Unit 1 fire hazards analysis is 13,600 btu / feet 2 The diesel's fuel and lubricants are being removed from the area.
This fire loading 2 and is well below the self imposed limit of 20,000 btu / feet as such we feel no structural steel protection is needed.
In addition, the cable in this area is being protected by a wet pipe sprinkler system which will aid in removal of the heat in the area.
2058 361 TAP /dle July 26, 1979
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