ML20073M579
| ML20073M579 | |
| Person / Time | |
|---|---|
| Site: | Braidwood  |
| Issue date: | 04/18/1983 |
| From: | Swartz E COMMONWEALTH EDISON CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| 6150N, NUDOCS 8304220113 | |
| Download: ML20073M579 (25) | |
Text
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/
's Commonwealth Edison
[
/ One First National Plaza, Chicago, Ilknois
(
7 Address Reply to: Post Office Box 767 C-y
,/ Chicago, lilinois 60690 April 18, 1983 Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC 20555
Subject:
Braidwood Station Units 1 and 2 Additional FSAR Information NRC Docket Nos. 50-456/457 Reference (a):
B.
J.
Youngblood letter to L. O. DelGeorge dated January 14, 1983
Dear Mr. Denton:
The above Reference requested that the Commonwealth Edison Company provide certain additional information concerning our FSAR for Braidwood Station Units 1 and 2.
The Attachment to this letter provides our response to Questions 10.61, 130.55, 130.57, 241.4, 241.5, 371.12, 371.16, and 371.18.
Our FSAR will be amended to include the information contained in the Attachment to this letter as appropriate.
Please address any questions that you or your staff may have concerning this matter to this office.
One (1) signed original and fifteen (15) copies of this letter with Attachment are provided for your use.
For the purposes of clarity, two (2) sets of 11" x 17" figures referenced in our responses to the above questions are being sent directly to Ms.
Janice A. Stevens.
Very truly yours
/
E. Douglas Swa Nuclear Licensing Administrator Attachment I
cc:
J.
G. Keppler - RIII RIII Inspector - Braidwood Ogi (
6150N 8304220113 830418 PDR ADOCK 05000456 A
e e
a BRAIDWOOD-FSAR, 2
QUESTION 010.61 (1)
Verify that failure of nonse'ismic Category I structures and equipment in the lake screen house following a SSE will not affect the exposed portions of essential service water supply lines above the lake screen house floor and thereby prevent essential service water flow.
(2)
Verify that the essential service water discharge structure is seismic Category I."
RESPONSE
(1) The substructure of the lake screen house, which' houses the essential service water intakes, is designed as a seismic structure.
Postulated failure of non-seismic portions of the structure and equipment will not' affect the intakes due to the location of the intakes away f rom any such structures and equipment.
In addition, the intakes are-protected by concrete enclosures protruding above the top of the mat.
The three intakes are also separated by 26.5 and 30 feet to prevent a single object fr'.m blocking two intakes.
(2) The essential service water discharge structure is seismic Category I.
I s
)
Q10.61-1 I
BRAIDWOOD-FSAR,
s QUESTION 130.55 "In Section 3.5.1.5 of the FSAR _you made a statement which implies that missiles were the only effect of the near-site explosion of a boxcar of TNT.
Specify if other loads, such as pressure, have been considered concurrently with
~
the missiles.as a result of the explosion.
Describe the missiles postulated as a~ result of the explosion, their energy content,'and' state the basis for conclusion reached in the FSAR that their -effects would be less than those lof the missiles. associated with the design basis tornado.
Also, describe the method and provide the results in sufficient detail to demonstrate that the above conclusion is correct when the missiles are considered in conjunction with the pressure resulting from such an explosion (Refer to the load combinations stated in the Standard Review Plan, Section 3.3.2.II.3). "
RESPONSE
A study has been made to estimate the potential hazard to the Braidwood Station from missiles generated in a postulated accidental explosion of one boxcar of TNT on the railroad 1550 feet from the station.
The typical average dimensions of a boxcar, i.e.,
car length of 50'-6", width of 9'-6", height of 11'-0" and a conservative wall plate thickness of 1/4" are used in the analysis.
A total of 66 tons of TNT explosives is considered.
The station has been evaluated for both primary and secondary f ragments.
Initial velocities for primary fragments have been obtained by using Gurney Energy.
This assumes a zero gap between the boxcar wall and the explosives, which results in conservatively
.high initial velocities of the f ragments.
The size and velocities lof primary fragments and the velocities of secondary missiles have been obtained by using equations given in Reference 1.
The impact of primary fragments on 'the roof is estimated from a high trajectory analysis which uses a terminal velocity approach and a conservatively assumed drag coefficient of 0.1, in determining the final striking velocities.
The evaluation is based on the probability of an explosion
~#
of 1.47 x 10 per year at the railroad near Braidwood Station, as given in Appendix lA -to Chapter 2.0 of the Braidwood PSAR (Reference 9 in the Braidwood FSAR, Subsection 2.2.4).
As explained in Appendix A, this number is derived based on conser-vative assumptions.
Q130.55-1
BRAIDWOOD-FSAR 3*
The results of the study are summarized below:
1.
Primary Fragments:
Primary fragments referred to here denote the fragments from the boxcar.
Tables Q130.55-1 and'Q130.55-2 summarize the results of primary fragments hitting the wall and the roof respectively.
The fragment which is of design concern h s a weight of 0.402 lbs (probability of occurrence
= 1 x 10.9.per year).
The velocity at which the design fragment strikes a wall is {956 ft/sec.
The corresponding kinetic energy is 2.38 x 10 ft-lbs.
The penetration depth is 2.8 inches and no spalling will occur on the other side of the wall (24 inch minimum wall thickness).
The velocity at which the design fragment strikes the roof is 607 ft/sec and the corresponding kinetic energy 3
is 4.6 x 10 ft-lbs.
The penetration depth in the roof is only 0.34 inch and no spalling will occur on the other side of the roof slab.
2.
Secondary Fragments Imoacting Concrete ~ Wall:
The blast waves from explosions can interact with objects located near the explosion source and accelerate them to high velocity.
these objects are called the " secondary missiles" or " secondary fragments."
Three secondary missiles have been postulated and evaluated in the analysis: (1) steel rod, 1-inch diameter x 3-feet long,. weight 8 pounds; (2) steel pipe, 3-inch diameter, schedule 40, 10-feet long, weight 78 pounds; and (3) 5/8 inch diameter 2-inch long bolt.
These secondary missiles are selected to cover a wide range of shape length, and weight of secondary missiles and also to give a perspective comparison with typical missiles generated by tornados.
Depending on
.the relative-orientation of these objects to the railroad track, they may or may not reach the' plant after'the postulated
-explosion.
Table 0130.55-3 indicates that even if these secondary missiles hit the wall, the impact velocities are very small and no scabbing will occur.
3.
Missile in conjunction with the Pressure Load:
It is noted that the primary and secondary missiles resulting from the postulated explosion may only cause local partial penetration in the walls'and roofs of the safety-related structures.
The overall structural-response due to these missiles are minimal as compared to the blast' pressure wave effect.
The evaluation-shows that the combined effect of the postulated m.issiles and pressure load is far less
'than the resistance capacities of'the exterior walls ~an'd roofs of the safety-related structures.
Q130.55-2
BRAIDviOOD-FSAR
?>*
Based on the above analysis it is concluded that missiles generated from an accidental explosion will not present a potential hazard at the Braidwood Statio.,.
Reference 1.
"A Manual for the ' Prediction of Blast and Fragment Loadings -
On Structures," DOE / TIC-ll268, U.S.
Department of Energy, November 1980.
i
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s n
0130.55-3 O
l l
t_
TABLE Q130.55-1
~.
~ ~
RESULTS FOR PRIMARY FRAGMENTS
~
~
HITTING CONCRETE WALL WEIGHT OF STRIKING STRIKING PENETRATION TIME OF PROBABILITY FRAGMENT, W VELOCITY, V ENERGY X
IMPULSE
- OF OCCURRENCE lb ft/sec ft-lb in.
see per year 4
-4
-7 0.402 1956 2.38x10 2.80 2.4x10 1.0x10 s
4
-4
-8 0.454 2084 3.06x10 3.29 2.6x10 7.35x10 4
~4
-8 0.590 2373 5.16x10 4.61 3.2x10 3.50x10 4
-4
-8 0'.772 2680 8.61x10 6.39 4.0x10 1.47x10 5
-4
-9 d.934 2905 1.22x10 7.97 4.5x10 7.35x10 c)
H F'
5
-4
-9 C'
g 1.167 3170 1.82x10 10.20 5.4x10 3.00x10 g
5
-4
-9 1.372 3364 2.41x10 12.11 6.0x10 1.47x10 1
2 X'
- Time of rectangular impulse for overall response.
i S
+
TABLE Q130.55-2 RESULTS FOR PRIMARY FRAGMENIS HITTING CONCRETE ROOF WEIGHT OF STRIKING PENETRATION TIME OF PR BABILITY FRAGMENT, W VELOCITY, V X
IMPULSE OF OCCURRENCE lbs ft/sec ik.
(sec) per year
-4
-8
.402 607 0.34 1x10 1.3x10
-0
-0
.454 619 0.37 1.0x10 1.03x10
-4
-9
.590 647 0.45 1.2x10 4.89x10
-4
-9
.772 676 0.54 1.3x10 2.05x10 C) s
-0
-9
.934 698 0.61 1.4x10 1.03x10 E
O
-4
-10 l
1.167 724 0.72 1.6x10 4.19x10
-4
-10 1.372 744 0.80 1.8x10 2.05x10 x
n nm 1
~
ll m
w&+e-e ew MeeM M
r TABLE'Q130.55-3 I
~'
RESULTS FOR SEC01 DARY MISSILES 1
l PROJECTFD IMPACT VELOCITY
_ARMA( f t )_
ft./sce.
REMARKS POSTULATED MISSILE _
i
-3 Steel rod,1 in. diameter x 5.45x10 No Ilit
{
3 ft. long, weight 8 lbs (minimum) l 2.5x10 58.63
- No Spalling
~I (maximum)
~2 4
1.594x10 No Hit Steel pipe, 3 in, diameter, schedule 40,10 f t. long, (minimum) to weight 78 lbs h
o 64.14 No Spalling U
2.5 (maximum)
F.
?
o tn oT.
us i
~3 115.0 No Spa 11ing 5/8" diameter bolt, 2 in.
9.39x10 y,
length, weight.314 lb.
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4 BRAIDWOOD-FSAR,
2 QUESTION 130.57
" Comparison of Table 3.2-1 (sh.4) and Section 3.8.4.1 reveals an apparent discrepancy regarding the classification of-the Essential ~ Service Water Discharge Structure (ESWDS).
The ESWDS is classified as Category I in Table 3.2-1 but it is not included in Section 3.8.4, Other Seismic Category I Structures.
You are requested to clarify this discrepancy and, assuming-that>the~ESWDS-is' classified"as~a Category I
. structure, provide all the pertinent information~regarding its design, location.and, construction."
RESPONSE
The essential service vater discharge structure (ESWDS) is designed as a seismic Category I structure.
It is a reinforced concrete structure designed to provide anchorage for the discharge end'of the essential service water pipes in the essential service cooling pond (see Figure 3.8-80).
Subsection 3.8.4.1.10 will be revised to include the above description of the ESWDS.
S I
i 0130.57-1 e
i
[
}
4 F
BRAIDWOOD-FSAR
[
c QUESTION 241.4 "The extent or limits of slurry trench cut off shown in 6
FSAR Figure 2.5-74 does not agree with that described in the FSAR text (page 2.5-109).
Explain this discrepancy.
Also, provide a plan showing slurry trench cut off around the cooling lake and Essential Services Cooling Pond and J
verify that the slurry trench cut off is continuous and can be -relied upon to-act as a seepage barrier for the ESCP."
RESPONSE
The slurry cut off trench beneath the perimeter dike system, referred to on page 2.5-109, is the slurry trench cut off for the perimeter dike of the cooling lake.
A plan view showing the boundary of the cooling lake which coincides with the perimeter dike slurry trench is given in Figure 2.4-37.
The slurry trenches shown in Figure 2.5-74 are. trenches that were installed prior to main plant and lake screenhouse construction to assist in construction dewatering of these facilities.
These trenches are not considered permanent installations and should not be confused with the cooling lake perimeter dike slurry trench.
The cooling lake perimeter dike slurry trench is continuous around the perimeter of the cooling lake and, therefore, continuous along the north and west sides of the essential service cooling pond (ESCP).
Plan views of the ESCP and perimeter dike along the north and west sides of the ESCP are civen in Figures 2.4-26 through'2.4-29.
Sections of the perimeter dike and slurry trench are given in Figure 2.4-35.
The slurry trench along the ESCP is a soil-bentonite' backfilled slurry trench extending from elevation.597 ' feet to top of -till and, in most cases, are keyed into till.
As-built profiles are provided in Figures Q241.4-1,.Q241.4-2 and Q241.4-3.
The design of "the ESCP does not rely on the slurry' trench as a seepage barrier.
The ESCP seepage has been conservatively determined assuming the slurry trench does not exist.
Existance of the slurry trench only makes the seepage analysis more conservative.
)
Q241.4-1
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BRAIDWOOD-FSAR, 2 QUESTION 241.5 " Provide the following information for seismic Category I Essential Services Water Discharge Structure: (1) Maximum bearing pressures, and factors of safety against sliding, overturning modes of failure for both static and dynamic loading conditions. (2) Discuss the liquefaction potential of the material surrounding and beneath the Essential Services Water Discharge Structure. (3) Furnish a plan showing the location of the Essential Services Water Discharge Structure'with reference to Essential Services Cooling Pond (ESCP). Discuss the potential for the blockage of discharge structure openings in the event of a flow-type failure of the slopes of the ESCP as a result of a Safe Shutdown Earthquake." RESPONE (1) The maximum bearing pressures and factors of safety against sliding and overturning modes of failure for both static and dynamic loading conditions are given in Table Q241.5-1. (2) The essential service water discharge structure is founded on approximately 23 feet of Wedron glacial till deposit-overlying the Carbondale bedrock formation. (See boring H-4, Figure 2.5-159, sheet 16.) The glacial till is stiff to hard and not susceptible to liquefaction. The essential service water discharge structure is backfilled with previously excavated sand compacted to minimum 85% relative density in accordance with. ASTM D 2049. Results of eight field density tests indicate relative densities ranging from 90% to 121% and ave 5 aging 1 4%. The average field dry density is 113.4 lb/ft This backfill is not susceptible to liquefaction. The liquefaction potential of the adjacent natural sand deposit forming the ESCP foundation soils is discussed in Subsection 2.5.6.5.2. (3) A plan showing the location of the essential service water discharge structure with reference to the ESCP is given in Figure 2.4-28. Sections through the structure are given in Figure Q362.8-1. 'The ESCP slope' south ~of the Q241.5-1
H r BRAIDWOOD-FSAR structure is 10 horizontal to 1 vertical. The stability of the slope has been analyzed and results presented in Subsection 2.5.6.5.1.2. r. In the event that a flow-type failure occurred as a result of the SSE, the discharge pipes would not be blocked with material from the slope. The invert of the discharge pipes is at elevation 591.0 feet. The top of the 10 to - 1 slope is -greater than 110 feet south of the discharge "The pipes and has been graded to elevation 590.0 feet. toe lof the interior dike is approximately 215 feet south of the discharge pipes at its closest point. The interior dike has been designed to be stable under OBE conditions and is of sufficient distance away from the discharge pipes to have no potential effect on their operation. It is concluded that the discharge pipes will not become blocked from any flow-type slope failure. O e e 9 9 O e O241.5-2
TABLE Q241.5-1 MAXIMUM BEARING PRESSURE AND FACTORS OF SAFET FOR ESSENTIAL SERVICE WATER DISCHARGE STRUCTURE 3 Dynamic Loading _ Static Loadinq OBE SSE Case I Case II Case I Case II Case I Case II t Max'imum Bearing Pressure, KSF 1.22 1.26 1.42 1.46 1.66 1.70 Factors of Safety Against Sliding in Direction of Pipes '(Section G, Figure Q362.8-1) 5.3 5.0 6.4 6.4 5.9 5.9 s - o o Against Sliding in Direction M b Perpendicular to Pipe (Section F, Figure Q362.8-1) 36.2 28.3 2.8 2.8 1.1 1.1 u, i Agains't Overturning (Section 'y G, Figure Q362.8-1) 2.4 2.5 2.0 2.1 1.5 1.6 Against Overturning (Section F, Figure Q362.8-1) 2.6 2.8 1.8 1.9 l.2 1.3 Water Surface at Elevation 598.2 feet (Flood Codditions) Note': Case I Case II - Water Surface at Elevation 587.0 feet. l e
BRAIDWOOD-FSAR ) QUESTION 371.12 (1) Reference previous Questions 371.2 and 371.4 concerning site. drainage. Although the applicant response (Amend 18 and 21) provides some additional information, the FSAR section still does not contain sufficient infor- - mation for the staff to determine that provisions for site drainage are adequate. We recommend that the applicant be prepared to discuss this -subject in detail during the site visit and document the infor-mation..in the FSAR. We will expect to review with the' design engineer (s) the following: (a) Method used to determine subarea hydrographs or peak discharges, time of concentration, contri-buting areas and precipitation values. (b) With appropriate full scale topographic mapping, review the subarea configurations,-flow paths, culverts, swales, ditches and road weirs used to convey flow from the site area. (c) Discuss the potential for partial or full blockage of culverts. You should consider potential for debris, especially during early stnges of operation when area construction debris is likely and the effect of relative culvert size (most of yours ~ are relatively small diameter) on potential blockage. (d) Consideration of security requirements on site drainage. The staff has recently encountered altered drainage as a result of security fencing, berms, etc., at the Grand Gulf site. The applicant should coordinate site drainage requirements with planned security provisions. (e) You state that area F will pond below plant flood elevations. Since you don't discuss routing or. outflow,.we must assume that the entire 48 hour PMP volume is stored, which would require about three feet of depth. Since ditch invert elevations are shown at 597.0, we don't think the volume is available. We need to discuss your methodology for this area." Q371.12-1
r 4 BRAIDWOOD-FSAR L
RESPONSE
The analysis for local intense precipitation has been revised. It is assumed that the site drainage system and the culverts will not be functioning at the time of local intense precipitation. The detailed description and results of the analysis are presented in revised Subsection 2.4.2.3. During the site visit on -March 30, 1983, the revised analysis was discussed with Mr. Gary Sta' ley, NRC hydrologist. Full scale site drainage and grading, and other related drawings were presented during the discussion. The general alignment of the security fence as shown on the site drawings was shown, and it was noted that the top of footing of the security fence will be at grade level or below. It was agreed that the revised analysis is acceptable and no further questions on this analysis remain to be answered. e e = 1 [' 4 e 0371.12-2 e
I BRAIDWOOD-FSAR adjusted to the Wilmington site by multiplying the Custer Park discharge by the ratio of the square roots of the drainage areas. The maximum known discharge near Wilmington, 75,900 cfs, occurred July 13, 1957. Its corresponding gauge height was 11.40 feet above datum. The maximum stage during the period of record was 13.88 feet, caused by ice jams. Ice jam floods in 1883 and 1887 reached-a stage of 16.73 feet, for which the" discharge is not known. All maximum stages greater than those due to floods were. caused by ice. jams. Of the 36 years..for which maximum water surface elevations are known, 18 maximums were caused by ice jams as high as almost 7 feet above the year's highest flood stage (see subsection 2.4.7). 2.4.2.2 Flood Design Considerations The plant main floor is located at elevati'on 601.0 feet, which is above all flood levels from nearby rivers, streams, and reservoirs. The cooling pond dike system is higher than the calculated flood elevation with coincident wind wave action. The probable maximum precipitation (PMP) water surface elevation of the pond is below. safety-related facilities. Floods occurring on the Kankakee River could affect only the river screen house, which is a non-safety-related structure supplying makeup water .to the cooling pond. Other streams in the area pose no flood-threat to safety-related items. The site drainage system has been designed to pass rainfall without flooding. There are no dams upstream on nearby rivers whose failure could cause flooding at the site. The general terrain of the area is flat, with no location at which landslides could cause flood waves at the site. The controlling event for flooding at the site is the probable maximum flood for the cooling pond (see subsection 2.4.8.2). This event has been analyzed by applying the local probable maximum precipitation (PMP) to the pond, watershed following an antecedent storm equivalent to one-half the PMP (see Subsection 2.4.8.2.4). 2.4.2.3 Effects of Local Intense Precipitation Site grading and drainage are designed to assure that the local PMP will have no effect on safety-related facilities. The layout of roads, tracks, and drainage in the immediate plant -area is shown in Figure 2.4-7. PMP data -are taken 'f rom Hydrometeorological' Report No. 33 (Reference
- 2) and is estimated to amount to 31.9 inches over a 48-hour period.
This is the summer PMP, which is greater than the -largest winter PMP coincident with the water equivalent of the 100-year snow pack. The PMP time distribution in 6-hour and 1-hour periods is given in Tables 2.4-2 and 2.4-3. The { M1-D
~ 4 BRAIDWOOD-FSAR .y Q = CIA, where peak runoff (cfs) Q = coefficient of runoff C = intensity of rainfall (inches / hour) ~ I = drainage area (acres). A = 'The coe'fficient of runoff was estimated'by using a weighted average of the values obtained for the building roofs,. roads, -graded and other areas (Reference 2a). 1The time of concentration was computed from Kirpich's formula (Reference 2a). The intensity of rainfall corresponding to a time of concentration was interpolated from Table 2.4-4a. The water surface elevation was estimated for peak flow over the peripheral roads and railroads sing a broad crested weir formula with a coefficient of disenarge of 2.7. The plant site area is divided into Zones A, B, C, and D as shown in Figure 2.4-7a. The storm water, which accumulates in Zone A, flows over two peripheral roads southwest of the plant buildings. The overflow length of the road is approximately 160 feet at elevation 600.0 feet. The area of Zone A is 13.1 acres. The weighted runoff coefficient is estimated as 0.69 and the time of concentration is 16 minutes. The peak runoff from zone A is 285 cfs, which will flow over the peripheral road and would produce a water surface elevation near the plant buildings of 600.75 feet. If the value of runoff coefficient is conservatively assumed to be 1, the peak runoff from Zone A would be 413 cfs, with a water surface elevation of 600.97 feet near the plant-buildings. The runoff from Zone B flows over railroad track 1 on the east, and over track 4 on the north. The total overflow length as shown in Figure.2.4-7a is.1,650 feet,.and the top of the rail is at elevation 601.0 feet for these two tracks. The area of Zone B.is 27.3 acres. An estimated runoff coefficient of 0.63 was used, with a time of concentration of 20_ minutes. The peak runoff from Zone B is 496 cfs, which will flow over the peripheral railroad and produce a water surface elevation of 601.23 feet near the plant buildings. If the value of the runoff coefficient is conservatively assumed to be 1, the peak runoff'from Zone B would be 787 cfs, with a water surface elevation of 601.32 feet. 2.4-5
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l i BRAIDWOOD-FSAR '., ) OUESTION 371.16 "The PMF and coincident wind may not be the critical event for structural design of the pond screenhouse. The applicant should consider enough combinations to be assured that the most critical event has been-identified. Past experience indicates-that in similar situations the maximum gradient wind on'the normal pond level with coincident seismic loading may be the controlling design, especially if this scenario yields breaking waves. _ Provide a table that . lists. pertinent parameters, including the -water -induced ~1oads-for the scenarios investigated."
RESPONSE
Refer to the response to Question 371.18. e s ~ e Q371.16-1
^ BRAIDWOOD-FSAR } QUESTION 371.18 ~ "The statement to Page 2.4-18, 2nd paragraph, conflicts with,the information in the 4th paragraph on;page 2.4-4, which indicates different design bases for the pond screen house. Apparently different portions of the screen house have different design bases. Provide additional discussions to clarify this apparent discrepancy. Provide the design bases forces (water induced) for the safety related portion of the. pond screen house."
RESPONSE
As described in Subsection 3.8.4.1 the substructure of the lake screen house is designed as a. Category I structure. The substructure houses the intakes of the essential service water lines. The essential service water pumps are located in the Auxiliary Building. The hydrostatic and hydrodynamic forces in combination with seismic events were used in the design of the substructure. Dynamic wave effects resulting from 40 mph wind coincident with PMF pool, and 60 mph wind coincident with normal pool were considered. hhebottomelevationoftheessentialservicecoolingpond (ESCP) is at elevation 584 feet 0 inch. Locally the grade around the lake screen house on the lake side is at elevation 570 feet.2 inches. Due:to the large depth available in comparison to the wave height (Tables 2.4-11 and 2.4-13) at the lake ' screen house, the breaking waves'will not occur for different lake levels. The forces due to wind generated waves, and the relevant wave parameters are presented in Table Q371.18-1. Q371.18-1 e
BRAIDWOOD-FSAR TABLE 0371.18-1 WAVE PARAMETERS APPLICABLE TO THE LAKE SCREENHOUSS Normal Normal
- PMF Parameter Pool Pool
' Pool L2ke' Water' Level (feet) 595 595 ~ 598.'17 - Fctch. Leng th (miles) 0.45 1.25 .l.25 Overland Wind Speed (mph) 60 60 40, Significant Wave Height (feet) 2.3 3.0 2.35 Wove Period (seconds) 3.4 2.37 2.39 Average Depth (feet) 11.0 11.46 11.46 Depth at.the Structure (feet) 24.8 24.8 28.0 W;ve Breaking (B) or Non-Breaking (NB) NB NB 4U3 Hydrostatic Force (lb./ft) 19,190 19,190 24,461 H2ight of Line of Action Above Grade (feet) 8.33 8.33 ~9.33 Hydrodynamic Force (lb./ft) 700 2,260 793 ~ H3ight of Line of Action Above Grade (feet) 13.92 14.25 15.55 D cAssumed internal dikes not existing. l l l Q371.18-2 5}}