ML20078R775

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Structural Steel Analysis:Reactor Bldg,Elevation 217 Ft, General Floor Area,Fire Area 44
ML20078R775
Person / Time
Site: Limerick Constellation icon.png
Issue date: 11/01/1983
From:
PROFESSIONAL LOSS CONTROL, INC.
To:
Shared Package
ML20078R738 List:
References
NUDOCS 8311150287
Download: ML20078R775 (7)
v • d • e


Text

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(([ Professional Loss Control, Inc.

STRUCTURAL STEEL ANALYSIS for LIMERICK GENERATING STATION Unit 1 ,

Reactor Building El. 217' General Floor Area Fire Area 44 November 1, 1983 8311150287 931100 PDR ADOCK 05000352 PDR E

1 7922 West Chester Pike

  • Upper Darby, Pa. 19082 * (215) 853 1700 9

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LIMERICK GENERATING STATION

-1. AREA DESCRIPTION The area under consideration is the general floor area on the 217' ele-vation of the Unit 1 Reactor Building (Fire Area 44). The heaviest com-bustible loading encountered on this elevation is found in the northeast corner. The area of heaviest combustible loading is bounded by column lines 19.4 & 21 sand J & Fb (see Attachment A for a sketch of the area under consideration). The bounding walls in the area are of reinforced concrete with an average thickness of 3 ft. The total surface area for heat transfer is 11,309 ft2 (see Attachment A for calculation of areas).

2. COMBUSTIBLE LOADING The heaviest concentration of cabling found within this area was cen-tered along column line 21.5. The average combustible loading of the cable trays in this area is 3.2 lb/ft2 of tray surface area. There are no combustible liquids in this area. Enclosed combu'stibles are not included in the combustible loading.
3. VENTILATION PARAMETERS The area under consideration is open to the remainder of this elevation on its south side. This opening is approximately 13 ft. wide by 35 ft.

high.

4. CASES EXAMINED A spreading cable fire was assumed to originate in the area of heaviest cable concentration in order to present the worst case. The fire is assumed to start at a point source and spread horizontally along the cable trays in each direction at a rate of 10 ft per hour. The fire will spread along all of the horizontal cable trays intersecting the point source for a distance of 5 feet in each direction before the original point source dies out af ter 32 minutes. A maximum surface area of 186 ft2 of cable trays (see Attachment B for a list of trays) will be involved at any one time, which corresponds to a heat output of 3284 kW.

This heat output is assumed constant throughout the fire duration. The actual heat output as the fire spreads out of the area originally involved would be less since the quantity of cabling that would be involved at any one time would be less.

1

5. RESULTS-The fire duration was taken to be 180 minutes and the fire temperature reached after 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> was 508 F which is below the critical temperature for the structural steel (see Attachment C for results of analysis).

Since the fire was assumed to occur in the area of heaviest combustible loading,-the results are considered to be representative for the entire general floor area on the 217' elevation of the Reactor Building.

The location of cable trays relative to structural steel members were examined throughout the 217' elevation of the Reactor Building in order to assess the potential for localized heating. No cable trays were positioned so as to present a localized heating exposure to structural steel.

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U : . _= :. lAlb Unit 1 Safeguard Systems El. 217' Northeast Corner Surface Area Calculation Walls Nortn wall (51' x 34.5') 1759.5 ft2 North wall stairway (8'x34.5') 276 ft2 East wall stairway (18' x 34.5') - (3' x 7' door) 600 ft2 West wall (H to Fb) (51' x 24') 1224 ft2 East wall (stairway to Fb) (55' + 2' x 3') x 34.5' -

2104.5 ft2

South wall at H (13' x 24') 312 ft2 South wall at Fb (10.5' x 34.5') - (3' x 7' door) 341 ft2 Drywell to Fb (30.5' x 34.5') + (51' x 24') 2276 ft2 8893 ft2 1

e ATTACHMENT A

.:u Ceiling Area 1 (5' x 24') 120 ft2 Area 2 1/2 (24' x 19') - 42 ft2 186 ft2 Area 3 (24'.x13') 312 ft2 Area 4 (31' x 16') 496 ft2 Area 5 (13' x 5') 65 ft2 Area 6 (4' x 3') 12 ft2 Area 7 (21' x 42') 882 ft2 Area 8- (49' x 5') 245 ft2 Area 9. 1/2(28x 8') 42 ft2 70 ft2 Area 10 -1/2(21' x 4') - 14 ft2 28 f t2 2416 ft2

' Total Surface Area for Heat Transfer 11,309 ft2 s

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9 ATTACHMENT A

r The following cable trays are present in the area defined for the source fire and all- of the trays are assumed to.be burning simultaneously:

Surface Tray No. Width (in) Length (ft) 2 Area (ft )_

IBCTA70 24" 17' 34 IBCVA70 24" 17' 34 1BCVA70 -24" 17' 34 1BCWA70 24" 10' 20 10CRA63 24" 6' 12 10CRA62 24" 4' 8 10lWA63 24" 8' 16 10lXA62 24" 2' 4 10lWA62 24" 2' 4 10lXA70 24" 10' 20 186 ft2 Average Combustible Loading per Tray Surface Area = 3.2 lb/ft 2 Fire Duration for Free Burning Tray Fires =

- 3.2 lb/ft2 4 0.1 lb = 32 minutes ftc/ min Heat output with all trays in source fire area (above) burning

. simultaneously:

186 ft2 _ x 190 kW/m2 = 3284 kW 10.76 ft4/mL l

ATTACnMENT B L._..

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CASE, NUMBER: 1

-BUILDING : - L L' NIT 1 REACTOR BUILDING ELEVATION AND AREA DESCRIPTION: 217' -GENER AL FLOOR AREA CASE DESCRIPTION: SPREADING CABLE FIRE-

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CEILING / WALL CEILING / WALL Ao :Ho Aw Q-THICKNESS MATER I AL-(ft) (ft2)- (ft) (ft2) (kW)

  • * * *
  • x
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  • x * * * * * * * *
  • x * * * * * * *
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  • x
  • x x * * * * * * * * * * * * * * * * *
  • x x x * * * * * * *
  • 13.0 CONCRETE 452 35 11309 3284 FIRE IS FUEL CONTROLLED

. FIRE DURATION ' GAS TEMPERATURC-(nin)- (deg.F) 10 175 20 217 30 250 40 277

-50 -302-60 324 70 344 80 362 90 380 100 397

'110 412 120' 428 130 442 140 4'a6 150- 470 160 403 170 495 100 508 1

4 ATTACHMENT C 5

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