ML18150A375

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Rev 2 to Transfer Canal Door Drop Analysis for Surry Power Station Units 1 & 2.
ML18150A375
Person / Time
Site: Surry  Dominion icon.png
Issue date: 12/06/1984
From:
NUCLEAR ENERGY SERVICES, INC.
To:
Shared Package
ML18150A294 List:
References
REF-GTECI-A-36, REF-GTECI-SF, RTR-NUREG-0612, RTR-NUREG-612, TASK-A-36, TASK-OR 83A1040, 83A1040-R02, 83A1040-R2, TAC-60309, TAC-60310, NUDOCS 8605210346
Download: ML18150A375 (32)
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  • NUCL& ENERGY SERVICES, INC. oocu&T NO. 83AI040 REV._2__
  • 1 111!.5 AIIIVFOI'~ PAGE 1 OF 32 TRANSFER CANAL DOOR DROP ANALYSIS FOR SURRY POWER STATION UNITS 1 & 2 Prepared Under NES Project .52.58 for VIRGINIA ELECTRIC AND POWER COMPANY Co ~JTDOLI E" c-,nit, Iii l ~. '

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11e.5 REVISION LOG NUCLEAR ENERGY SERVICES, INC.

PAGE _ 2_ _QF_3_2_*_

REV. PAGE DATE . DESCRIPTION* APPROVAL NO. NO. -

1 11/16/84 Added Load Cases (c) and (d) Per CRA 4845 ~~

2 12/6/~ll Dpvic ...1'4 c;;Prtions I and 9 Per CR A "'A77 ,hi~-

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A ....r o , ~ 3 32 PA.GE - - - - O F NUCLEAR ENERGY SERVICES TABLE OF CONTENTS PAGE I.

SUMMARY

4

2. INTRODUCTION 4

.3. DESCRIPTION OF SPENT FUEL POOL, TRANSFER CANAL DOOR AND RACKS 5

4. APPLICABLE CODES, STANDARD AND SPECIFICATIONS 10
5. LOAD CASES 10 5.1 Case (a): Vertical Drop on Pool Floor 10 5.2 Case (b): Inclined Drop on Pool Floor 10 5.3 Case (c): Inclined Drop over a Leak Test Channel 10 5.4 Case (d): Vertical Drop on a Fuel Storage Rack 11
6. ANALYTICAL PROCEDURES l.S 6.1 Velocity and Kinetic Energy of Impact 15 6.2 Local Damage to Concrete Floor 17 6.2.1 Depth of Penetration 19 6.2.2 Concrete Thickness to be Just Perforated 20 6.2 *.3 Concrete Thickness to be Just Spalled 21 6 *.3 Overall Structural Effects 22 6.4
  • Concrete Cracking 25 6.5 Damage to the Liner over a Leak Test Channel 25 6.6 Drop on Top of Fuel Storage Rack 25
7. STRUCTURAL ACCEPTANCE CRITERIA 26
8.

SUMMARY

OF RESULTS 27

9. CONCLUSIONS .30 1Oo REFERENCES 31 FIGURES

.3.1 Spent Fuel Pool Arrangement- Plan

.3.2 Spent-Fuel Pool Arrangement - Elevation 3.3 Details of Transfer Canal Door 3.4 Spent Fuel Storage Rack 5.1 Door Drop Accident - Load Cases A and B 5.2 Inclined Drop over a Leak Test Channel - Load Case C S.3 Vertical Drop on a Fuel Storage Rack - Load Case D TABLES Table 8.1 Results of Door Drop Analysis - Load Cases A and B Table 8.2 Results of Door Drop Analysis - Load Case D

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32 I.

SUMMARY

This report, prepared for Virginia Electric and Power Company, presents the* results of the transfer canal door drop analysis for Surry Power Station Units l and 2. Nuclear Energy Services, Inc. has performed the door drop analysis to evaluate the potential structural damage to the spent fuel pool floor and to the spent fuel storage racks due to the postulated door drop accident from the highest elevation of the crane hook*

.Fo~r cases ha:ve been considered; a) Vertical Drop on Pool Floor, b) Inclined Drop on Pool Floor, c) Inclined Drop over a Leak Test Channel and d) Vertical Drop on a Spent IA Fuel Rack. The maximum velocity and kinetic energy of impact, local damage as well as overall structural response and potential consequences have been evaluated for each I ~

of these cases. The analyses have been performed using empirical equations and

  • energy/momentum balance methods described in references 1, 2 and 14. Based upon the results of the analyses, it is determined that the overall integrity of the racks, as well as the pool floor is maintained, and the leak tightness of the liner is not compromised.
2. INTRODUCTION*

After the door is raised to its.highest elevation over the spent fuel pool, the door is postulated to drop straight down and strike either the top of the racks, or the pool floor. Two drop attitudes have been considered for impact on the pool floor: the door dropping in the upright position with its axis vertical and the door dropping on its shortest edge at an angle. For impact on top of the racks, the minimum area of contact is postulated.

For each of the rack drop accident cases, the maximum velocity and kinetic energy at the instant of impact, local effects and the overall structural response have been determine<{~ Local effects consists of: (1) rack penetration into the target (top of rack or pool floor), (2) rack perforation through the target (pool floor), and (.3) spalling of the pool floor~ Empirical equations presented in References 1, 2, and 4 have been used in evaluating local effects. The overall structural response has been evaluated using energy balance methods described in References 1, 2, and 10.

Section 3 of this report presents pertinent descriptions of the door, the storage racks, and the spent fuel pool. Applicable codes, standards and load cases considered in the analyses are given in Sections 4 and .5 respectively. The analytical procedures and

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structural acceptance criteria are summarized in Sections 6 and 7. The results and conclusions of the analysis are presented in Sections 8 and 9 of the report.

3. DESCRIPTION OF SPENT FUEL POOL, TRANSFER CANAL DOOR, AND RACKS The spent fuel pool is a Category I structure. Its primary functions are to load, unload, transfer and store used fuel assemblies. A schematic plan of the Surry Power Station Units 1 and 2, spent fuel pool ls shown in Figure .3.1 (Ref* .3). Figure .3.2 shows the elevation of the spent fuel pool.

The spent fuel pool ls a 72'-6" long, 29'-.3" wide and 42 1-611 deep reinforced concrete well resting on rock foundation. The floor and walls of the pool are 6 feet thick concrete structure reinforced with Ill I bars at 12 inches, each way, each face. The pool is lined with a 1/4-inch thick stainless steel liner plate. Drawings of Reference 3 show the mechanical and structural details of the spent fuel pool. Details of the transfer canal door is shown in Figure .3.3. The door is constructed from stainless steel and weighs 3600 ~s (~ef .3).

Each fuel storage rack consists of a six by six array of fuel storage cells which are square stainless steel boxes spaced nominally 14 inches on centers. The rack is shown on the general arrangement drawing (Figure 3.4).

The. fuel storage rack has two basic components: the support structure and the fuel storage cell. The support structure consists primarily of the four corner storage cells which interface with the spent fuel pool floor pads and two horizontal grid members w~lch are supported by the four corner cells and which maintain the horizontal position and vertical alignment of _the remaining thirty-two (inner) storage cells. The inner storage cells rest directly on the spent fuel pool floor. Diagonal bracing is provided oA-the structure to accommodate the loads imposed on the rack.

Each corner storage cell is nominally 9.56 inches square (O.D.) by -172 inches long with 0.250 inch walls. Each of the thirty-two inner storage cells is nominally 9.12 inches square (O.D.) by -110. inches long with 0.090 inch walls. The cells are flared at the top to aid in insertion of the fuel assembly into the cell. . Attached to the bottom of each cell are four stainless steel posts which support the fuel assembly. The posts attached to the thirty-two inner cells rest directly on the floor of the spent fuel pool.

The rack ls designed to permit the inner cells to move vertically within the rack structure (a .:t 1 inch motion is provided).

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-- .32 FIGURE 3.4 SPENT FUEL STORAGE RACK

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NUCLEAR ENERGY SERVICES DOCUMENT NO. _ _8_3_A_l_0_40_ __

PAGE _ _ _ l O_oF 32

    • APPLICABLE CODES, STANDARDS AND SPECIFICATIONS The following codes of practice, regulatory guides and references have been used in the subject door drop analysis.

I. ACI .318 "Building Code Requirements for Reinforced Concrete" American Concrete Institute, 1979.

2. AISC "Specifications for the Design, Fabrication and Erection of Structural Steel for Building", 1980*

.3. USNRC Regulatory Standard Review Plan, Section .3.8.3 and Section .3.8.4; Directorate of Licensing U.S. Atomic Energy Commission.

5. *LOAD CAsES After the door is raised to its highest elevation over _the pool area, the rack drops and strikes the pool floor. The following four conditions have been considered.

5.1 CASE (A): VER TI CAL DROP ON POOL FLOOR The 3600 lb. door drops from a height of 34' - 10 1/2" and strikes the pool floor in the upright position with its axis vertical as shown in Figure 5.1 (a).

5.~ CASE (B): INCLINED DROP ON POOL FLOOR The 3600 lb. door drops from a height of 34' - 10 1/2" and strikes the pool floor at an angle which would cause the maximum structural damage to the pool floor as shown in Figure 5.1 (b) *

.5 *.3 CASE (C): INCLINED DROP OVER A LEAK TEST CHANNEL Case (C) is postulated to occur over a leak test channel on the pool floor, as shown in Figure 5.2.

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S.4 CASE (D): VERTICAL DROP ON SPENT FUEL RACK The door drops vertically over the storage rack such that the contact area is minimum. Parameters used in the analysis are shown in Figure S.3.

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FIGUREl.2 INCLINED DROP OVER A LEAK TEST CHANNEL - LOAD CASE C f ...>RM

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NUCLEAR ENERGY SERVICES D~MENTNO.

83AI040 PAGE _ _1_4_QF 32 FIGURE S.3 VERTICAL DROP ON A FUEL STORAGE RACK - LOAD CASE D

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6. ANALYTICAL PROCEDURES 6.1 VELOCITY AND KINETIC ENERGY OF IMPACT For two door drop accidents A and B, the maxim~m velocity_ and kinetic energy at the instant of impact have been calculated by equating the change in potential energy to the maximum kinetic energy at the instant of impact. The maximum velocity and kinetic energy o*f impact have been calculated considering the effects of the buoyancy and. drag forces using the procedure given in detail in Reference 1 and as summarized below.

Assuming that the door drops vertically and conservatively neglecting the loss of velocity. during the compression phase of liquid entry and assuming a constant drag cerefficient, the equation of motion of the door is given by:

(1) where:

W = weight of door (lbs.)

2 g = gravitational acceleration (ft/sec )

x = depth of door e.g. below the initial e.g. (ft) t = time after initial contact of door with liquid (sec)

F b = bouyant force WY /y m' (lb) 2 F d = drag force = y Am CDv /2g (lb) 3 Y = weight density of liquid (lb/ft )

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NUCLEAR ENERGY SERVICES PAGE _ _ _1_6_QF 32 y m = weight density of door (lb/ft3)

A0 = horizontal cross-sectional area (ft2)

L = vertical length of the door (ft) c0 = drag coefficient Am = maximum horizontal cross-sectional area of the door .(ft2) v = x= velocity of the door at depth x (ft/sec)

Substituting and rearranging equation (1)

(2) where:

Solving equation (2) and using initial conditions yields v = V~ + e- 2ax bAo (e2ax (1 - 2ax) - 1) 2 2a *

+ VJ *+ g ( :r e2ax -1} (3) a ~m where:

= initial velocity of the door at x = 0

= striking velocity at x = H 112

= terminal velocity *= (g(l - 'tm )/a)

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NUCLEAR ENERGY SERVICES PAGE _ _ _1_7_QF 32 Maximum kinetic energy of impact E is given by:

2 (4)

E = 1/2 V W/g 6.2 LOCAL DAMAGE TO CONCRETE FLOOR The local damage to the impacted area (target) is largely independent of the dynamic characteristics of the structure. Local effects consist of: (l) penetration into the target, (2) door perforation through the target, and (3) spalling of the target. The following defines the local effects terminology and the various symbols used in their evaluation. The term missile. is used generically to instead of "door".

Terminology; Penetration: Penetration is the displacement of the missile into the target.

It is a measure of the depth of t.he crater fot:"med at the zone of impact.

Perforation: Perforation is "full penetration" or where the missile passes through the target with or without exit velocity (of missile).

Spalling: Spalling is the peeling of the back face of the target opposite to the face of impact. Spalling is referred to as scabbing in Reference 2.

Symbols:

W = weight of missile (lb.)

V ,V = striking velocity of missile (ft/sec.)

0 S d, D = diameter .of missile (in.)

A p

= _______ ___

Missile Weight (psf)

Projected frontal area of missile

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NUCLEAR ENERGY SERVICES DOCUMENT NO. _ _ _8_3A_10_4_0_ _

PAGE _ _ _1_8_0F 32 X = Depth of penetration into slab of infinitely thick concrete (in.)

t = thickness of the slab (in.)

f'c = comprehensive strength of concrete

= experimentally obtained material coefficient for penetration (see Reference 3).

N = Nose Factor = 0.72 + 0.25 ( n - 0.25) 1/2 n = radius of nose section diameter of missile K = concrete penetrability factor K =180 f'c N' = projectile shape factor T, e = perforation thickness (in.). The maximum thickness of a target which a missile with a given impact velocity will completely penetrate.

Ts, s = spalling thickness (in.). The thickness of target to be just spalled.

  • Local *damage depends on missile characteristics, target material properties and structural response. Because of . the complex phenomena associated with missile impact, empirical methods as given in References 1, 2, 6, and 11, have been used in estimating the local damage. These equations are summarized in Section 6.2.1, 6.2.2 and 6.2.3.

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NUCLEAR ENERGY SERVICES DOCUMENT NO. _ _ _8_3_A..;;.10.;. .4;.. ;;.0_ _

PAGE _ _ _l;;;.;9;_QF 32 6.2.1 Depth of Penetration The depth to which a rigid missile will penetrate a reinforced concrete target of infinite thickness can be estimated by the following formulas:

Modified Petry: (References 1, 6, 11)

X = 12K PAP log IO (1 + (5) 215,000 Army Corps of Engineers and National Defense Research Committee:

References 1, 6, 11.

282 W D 0.21.5 V 1*.5 (6) s X= + 0*.5D 1000 valid only for x ~ 0.6.5

. - i5 Ammann and Whitney: (References 1,2, and 6) 282 NW D 0. 2 V 1.8 (7) s X=

f' D2 1000 C

Modified National Defense Research Committee: (Reference 2)

X= 4KN'Wd ~ l.S for .! ~ 2.0 (8) 1000d

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NUCLEAR ENERGY SERVICES oluMENT NO. ___&_3...;.A_l_04_o_ __

PAGE _ _ _2_0_QF 32 Ref er to the references indicated above regarding various assumptions, restrictions etc. in the use of these formulas.

6.2.2 Concrete Thickness to Be Just Perforated The thickness of a concrete element that will be just perforated by a missile can be estimated by the following empirical formulas.

Modified Petry: (References 1, 6, 11)

T = 2X (9)

X is obtained from Equation .5 Ballistic Research Laboratories: (Modified) References 1, 2, 4 T = 7.8 w Vs 1*.33 (IO) 1000 Army Corps of Engineers: (References 1, 4) (11)

T = l.3.5D + l.24X X is obtained from Equation (6) valid only for .! > 1.3.5 D

National Defense Research Committee: (References 1, 4)

  • T = l.23D + l.07X (12)

X is obtained from Equation 6 L f .;RM

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D.UMENT NO. _ _ _8_3A_lo_4_o_ _

PAGE _ _ _2_1_QF 32 NUCLEAR ENERGY SERVICES Modified National Defense Research Committee: (Reference 2) 2 T = 3.19 X- 0.178 X for X < 1.3.5 (13)

D o o o-where x is obtained from Equation 8 6.2.3 Concrete Thickness to be Just Spalled:

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The thickness. of a concrete element that will just start spalling (spalling of concrete from the side opposite the contact surface) can be estimated by the following empirical formulas:

Modified Ballistic Research Laboratory: (References 1, 2, 4)

Ts= 2T (14)

Army Corps of Engineers (References 1, 4)

'rs= 2.2D + 1.3.SX (1.S)

Xis obtained from Equation 6 National Defense Research Committee (References 1, 4)

Ts= 2.28D + 1.13X (16)

Xis obtained from Equation 6 f .JRM

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__2__ QF 32 Bechtel Formula: (Ref.2) (17)

Ts = 1.5*.5 w0*4vo0 *.5 f'c Do.2 Modified National Defense Research Committee: (Reference 2) 2 Ts = 7.91 X - .5.06 X for X < 0.6.5 (18)

D D* D [)-

Where xis obtained from equation 8 6 *.3 OVERALL STRUCTURAL EFFECTS ON THE POOL FLOOR The overall structural effects on the pool floor resulting from drop accident &

events have been evaluated by assuming a hard missile impacting on a hard target. This is a conservative assumption since no credit is taken for local energy absorption. The kinetic energy transmitted to the floor structure by the &

missile has been calculated, based on the conservation of energy and momentum.

The energy absorption capability of the structure is limited by the allowable ductility criteria. For reinforced concrete compression members, the allowable ductility is 1.3 (Ref. 2).

For conservation of momentum, For conservation of energy, 2 2 2 1/2 mv = 1/2 mv + 1/2 M V 0

  • l e l where m = missile mass; Me = target effective mass; v O = velocity of missile before impact; v 1 = velocity of missile after impact; and V = velocity of target 1

after impact.

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NUCLEAR ENERGY SERVICES PAGE ____2_3_QF 32 An additional equation may be written defining the coefficient of restitution:

For plastic impact, energy is dissipated and the two masses move off at the same velocity (V = v ) and e = O. For elastic impact, e = 1 and energy is conserved.

1 1 It is always conservative to assume elastic impact, though in some cases a value of less than one for the coefficient of restitution may be justified based on experience. A value of e = 1 was therefore used for the present case. Solving for v , and substituting into the momentum equation, yields expressions for post-1 impact target and missile velocity:

m M

VI = *e (v (1 + e))

0 m

1+( - )

Me

( ~) - e M

vI = (v ) e o m 1+(--)

Me Note that for m/Me > e, the missile velocity is positive, and the missile is still moving toward the target. The residual velocity represents kinetic energy which the target must absorb in addition to that imparted to it during the initial impact. In equation form, the energy absorbtion capability of the target must be greater than:

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PAGE _ _....;2;;..;4_,QF 32 form< e M-e form> e

~e It is important to note that an underestimation of the target mass leads to a conservative estimation Qf the energy transmitted to the structure.

In terms of the allowable ductility and collapse load, the energy absorption capability of the structure (area under the resistance-displacement curve) is SE=

where SE = (strain) energy absorption

. capability of the structure; R m = static collapse

. load; Xe = effective yield displacemen+ (elastic displacement under a static load R ); and X = allowable displacement.

m m Substituting the definition of allowable ductility.

µ =

results in the expression:

SE = R X (µ - 1/2)

. m e Recommended values for the allowable ductility are published in Ref. 2. The structure withstands impact if SE is greater than KE

  • 1 In order to perform the momentum and energy balance calculations described above, a target structure inertial resistance or "effective mass" must be selected. Recommendations of Ref. 1 were used to establish the effective mass f ..>RM
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NUCLEAR ENERGY SERVICES PAGE _ _ _2_.5_QF 32 in a conservative manner, as that which is included within d/2 of the periphery of the impact surface, where d is the thickness of the target.

6.4 CONCRETE CRACKING The door drop accident is a relatively small impact in relation to the 72" thick .

concrete floor and tile foundation. This is further evidenced from the lack of * &

severity of the local damage presented in the "Results"_ section of this report.

The overall structural response is also well within the elastic limits. These factors indicate that gross cracking of concrete is not a possibility for this drop event.

6*.5 DAMAGE TO THE LINER OVER A LEAK TEST CHANNEL The leak test channel is relatively narrow, (approximately 2*.5" wide) compared to the shortest side of the door (7 .87.5"). Therefore, only an inclined drop is considered. Since the aspect ratio of the door is very large, the shortest edge is assumed to impact the liner. The maximum damage to the liner will occur due to the door edge impacting the liner centrally along the length of the channel.

However, because of the 6" radius of curvature of the edge of the door (see Figure 3.3), the impact load will get distributed over the width of the liner spanning the 2*.5" wide channel.

The impact velocity is assumed to be absorbed by the bending of the liner, until the deformation is such that the door contacts the surrounding concrete.

Thereafter, the impact is assumed to be carried only by the concrete.

6.6 DROP ON TOP OF THE FUEL STORAGE RACK For this analysis, it was assumed that the door drops vertically over a peripheral storage cell which has a 0.09" thick wall. The impact velocity is computed using the method described in Section 6.1 of this report. Absorption of the impact

  • energy due to the collapse of the lead.;.in flares at the top of the cell . is
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PAGE _ _ _2_6_0F 32 NUCLEAR ENERGY SERVICES conservatively neglected. One-half the cross-sectional area of the storage cell &

is assumed to resist the impact. The damage at the top of the rack is evaluated using the methods described in Reference 1.5.

7. STRUCTURAL ACCEPTANCE CRITERIA The acceptable maximum stresses in the reinforced concrete floor of the spent fuel pool are established based on *the-guidelines given in USNRC Standard Review Plan, Sections 3.8.3 and 3.8.4 and various design codes and standards (References 2, 7, 11, and 13). The acceptance criteria for a drop on the fuel storage racks is based on the &

requirements of USNRC Standard Review Plan 3.8.4. Loadings associated with rack I drop events are classified as extreme environmental loads. Acceptance criteria applicable to the factored load conditions are used in evaluation of structural effects.

These structural acceptance criteria are summarized below.

A. Degree of Damage to Spent Fuel Pool Floor - None Compressive. Stress = 1.2.5 x 0.8~ f'c= 4289 psi Shearing Stress = ~ f' = 234 psi C

Bearing Stress= 1.2.5 x 0.85g, 'f' = 3690 psi C

Yield Stress for reinforcing steel= 1.2 x 40000.0 = 48000.0 psi Where f' = Compressive Strength of concrete at 28 days= 4750 psi C

~ = Strength reduction coefficient = 0.85

~' = Strength reduction coefficient = 0.70 Factors 1.2.S and 1.2 are to account for increase in stress values for short term impact loadings (Reference 1).

B. DEGREE OF DAMAGE TO LINER Local damage to liner is permitted as long as the leak tightness of the liner plate is maintained.

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PAGE _ _2_7_oF 32 NUCLEAR ENERGY SERVICES C. DEGREE OF DAMAGE TO FUEL STORAGE RACK The overall integrity of the rack must be maintained and the criticality of the stored fuel must not be compromised. Also, the reaction load transferred to the pool floor should not compromise the leak tightness of the liner.

8.

SUMMARY

OF RESULTS Table 8.1 summarizes the results of the analyses for Load Cases A and B. The penetration, perforation and spalllng computations represent the range of predicitons as computed by the various methods described in Section 6. The stress results for the overall effects are based on the elastic impact assumption which is conservative, as described in Section 6.3. Results shown in Table 8-1 represent the worst case values of Load Cases A and B (vertical drop and inclined drop on the pool floor).

For Load Case C (inclined drop on liner plate over a leak test channel), it was found that the plate will deform a maximum of 0.132 inches. At this deflection, the door will contact the surrounding concrete and the remainder of the impact energy will be transferred directly to the concrete. The liner itself will yield along the edge of the leak test channel, and will rotate a maximum of 12 degrees at the yield plane.

However, because of the high ductility of the stainless steel, no fracturing occurs.

Table 8-2 summarizes the results of the analysis for Load Case D (vertical drop on top of rack). The maximum deformation at the top of the cell will be 2.42 inches, and the maximum punching shear stress generated in the liner will be 5.04 ksi. The overall integrity of the rack is maintained; however, the impacted cell will dislodge from the individual. cell support legs. As described in Section 3, the racks are designed for such vertical motions. of the individual storage cells.

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  • lle.5 NUCLEAR ENERGY SERVICES PAGE _ _2_8_QF 32 TABLE 8.1 RESULTS OF DOOR DROP ANALYSIS- LOAD CASES A & 8 (A) OVERALL EFFECTS CALCULATED ALLOWABLE Maximum Impact Load (K) 461.3 8485.13 Ductility Ratio < 1.0 1.3 Maximum Compressive Stress in Concrete (ksi) 1.502 4.29*

Maximum Punching Shear Stress in Concrete (ksi) 0.068 0.23*

  • Indicates allowable values for no damage criteria.

(B) LocAL EFFECTS

. MAXIMUM MINIMUM Penetration (in.) 2.459 0.109 Perforation (in.) 7.443 0.219 Spalling (in.) 22.830 2.745 (NOTE: Striking velocity was found to be 27.53 ft/sec.)

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PAGE _ _ _2_9_QF 32 NUCLeAR ENERGY SERVICES TABLE 8.2 RESULTS OF DOOR DROP ANALYSIS - LOAD CASE D Maximum Drop Height (in) 245.75 Kinetic Energy to be Absorbed (in-k) 336.60

.Maximum Stain in Storage Cell (in/in) 0.0148 Maximum CeH Deformation (in) 2.42 Maximum Transmitted Punching Shear (ksi) in Floor Liner 5.04 (22.5)*

  • Bracketed quantity represent the allowable value.
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9. CONCLUSIONS For Load Cases A and B, the pool floor will sustain local damage due to penetration at t the surface. However, the overall structural response shown in Table 8-1 indicates that the stresses and ductility ratios are well within the allowables for the no-damage criteria established in section 7 (A). The perforation and spalling criteria are also well within the available values for the Surry spent fuel pool.

For Load Case C, the liner over the leak test channel will deform a maximum of 0.132 inches. The dropped door will then transfer the load to the surrounding concrete.

Subsequent damage to concrete will be governed by Load Cases A and B.

For Load Case D, the impacted cell will dislodge from the individual cell support legs, and wil sustain 2.42 inches of permanent axial deformation. However, the integrity of ~

the rack and the leak tightness will not be compromised.

The following conservatisms in the door drop analysis should also be noted:

A. The effects of the 1/4" stainless steel liner plate are conservatively neglected in the analysis for Load Cases A and B. The ductile stainless steel liner plate will act as an energy absorbing cushion between the floor/wall of the spent fuel pool and the impacting door.

B. The door is conservatively assumed to be a non-deformable body with the target &

structure absorbing the entire impact energy. Local deformations of the ductile stainless steel door will, in effect, reduce the kinetic energy transmitted to the

~~ A C. The empirical equations and analytical procedures used in the analysis for Load .&

Cases A and B represent the present "state-of-the-art" in the field of design* of structures and components against missile impact. Although some of these empirical equations, generally apply to low mass, small diameter, high velocity missiles, their use in the design of the nuclear power plant structures for large mass, large diameter, small velocity missiles is judged conservative (Reference 1).

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NUCLEAR ENERGY SERVICES Based on the results of the analyses, it is concluded that the overall structural A integrity of the pool floor and the storage racks will be maintained. No loss of coolant will occur due to cracking of the floor or the fracture of the liner plate.

10. REFERENCES
1. "Design of Structures for Missile Impact", Topical Report, BC-TOP-9-A, Rev. 2.

Bechtel Power Corporation, September, 1974.

2. Structural Analysis and Design of Nuclear Plant Facilities; American Society of Civil Engineers, Manuals and Reports on Engineering Practice, No* .58, 1980.
3. Letter, W.C. Spencer, VEPCO, to R. Zemper, NES, Sept. 26, 1984, "PSE-180, Task Item 6, Transfer Canal Door Storage Rack, Surry Units 1 &*2.11
4. Gwalthey, R. C., Missile Generation and Protection in Light-Water-Cooled Power Reactor Plants, ORNL NSIC-22, Oak Ridge National Laboratory, Oak Ridge, Tennessee, for the U.S. Atomic Energy Commission, Sept., 1968.
5. Wood, R. H., Plastic and Elastic Design of Slabs and Plates, Ronald Press Co.,

1961.

6. Ammann and Whitney -. "Primary Fragment Characteristics and Impact Effects in Protective Design," Ammann and Whitney Consulting Engineers, New York, N.Y.
7. Building Code Requirements for Reinforced Concrete, American Concrete Institute, Standard 318=77, 19790
8.
  • Roark, R. J., Formulae for Stress and Strain, McGraw-Hill Book Co., 196.S.
9. Structures to Resist the Effects of Accidental Explosions, TM .S-1300, Department of the Army, Washington, D.C., July, 196.5.
10. Russell, C.R., Reactor Safeguards, MacMillan, New York, 1962.

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11. Fundamentals of Protective Design, TM .5-844-1, Headquarters, Department of the Army, Washington, D.C., July, 196.5.
12. Winter~ G., Design of Concrete Structures, McGraw-Hill Book Company, 1972.
13. USNRC Regulatory Standard Review Plan Section 3.8.3 and Section 3.8.4; Directorate of Licensing U.S. Nuclear Regulatory Commission.
14. "Final Structural Design of a Fuel Storage Well Crash Pad for LACBWR Nuclear ~

Power Plant", Nuclear Energy Services, Document No. 81A0426, Rev. 1, 1976.

1.5. "Structural Analysis Design Report for the Surry Power Station Units 1 and 2 High Density Fuel Storage Racks", Nuclear Energy Services, Document No.

81A0492, April 27, 1977.

FORM* NES 205 2180

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