ML20054B692
| ML20054B692 | |
| Person / Time | |
|---|---|
| Site: | Quad Cities  |
| Issue date: | 04/09/1982 |
| From: | Goddard R NRC OFFICE OF THE EXECUTIVE LEGAL DIRECTOR (OELD) |
| To: | Foster R, Kelley J, Morris P Atomic Safety and Licensing Board Panel |
| References | |
| ISSUANCES-SP, NUDOCS 8204190076 | |
| Download: ML20054B692 (2) | |
Text
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April 9,1982 James L. Kelley, Chairman Dr. Peter A. Morris Administrative Judge Administrative Judge Atomic Safety and Licensing Board Atomic Safety and Licensing Board Panel Panel U.S. Nuclear Regulatory Commission U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Washington, D.C. 20555 Dr. Richard F. Foster N
Administrative Judge g
g P.O. Box 4263 Sunriver, Oregon 97701 p
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In the liatter of
-g WS Commonwealth Edison Company s
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Docket Hos. 50-254-SP & 50-265-SP
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p (Spent Fuel Pool Modification)
Dear Administrative Judges:
Enclosed is the material provided to'Intervenors prior to their determination to withdraw Contention 9; the Staff deems the contention to be non-meritorious and supports the motion to withdraw.
l Sincerely, i
Richard J. Goddard Counsel for NRC Staff
Enclosure:
As stated cc:
see page two Distribution:
Goddard 50 7 Reis Lessy D
g C unninaham/fiurray Christenbury/Scinto OELD Formal Files (2)
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RBevan-416 Docket Files /PDR/LPDR 8204190076 820409 PDR ADOCK 05000254 g
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i cc: -Atomic Safety and Licensing Board Panel i
Atomic Safety and Lice., sing Appeal l
Board Panel Citizens for Safe Energy l
Quad-Cities Alliance for Safe l
Energy and Survival
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Older Americans for Elderly Rights Robert G. Fitzgibbons, Jr., Esq.
Docketing and Service Section Mr. Nicholas J. Chrissotimos 4
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! DATE :04/88/82
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${SN{l WR 31 Igp Mr. Robert Romic Mr. Douglas Collins Quad-Cities Alliance for Safe 622 4th Avenue, South Energy and Survival Clinton, Iowa 52732 1628 Grant Street Bettendorf, Iowa 52722 In the Matter of Commonwealth Edison Company (Quad Cities Station, Units 1 & 2)
Docket Nos. 50-254-SP and 50-265-SP
Dear Sirs:
Enclosed is the NRC Staff's Safety Evaluation of the new fuel Storage racks' struct$al integrity under all loading conditions, including those imposed f
by an SSE seismic event. The Staff has concluded that there is no threat to the public health and safety and as a result of the proposed modification.
The Staff must file interrogatories on Contention 9 NLT April 2, 1982, and responses must be served by you NLT April 16, 1982.
In light of our previous discussions, I would ask that you review this material immediately, with a view toward either framing specific questions to which you would like the Staff to respond or requesting the Licensing Board to allow withdrawal of this contention from the captioned proceeding.
Sincerely,
! n )- 4
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Richard J.
rd Counsel NRC Staff
Enclosure:
As stated cc:
Phillip P. Steptoe, Esq.
Older Americans for Elderly Rights Mr. Nicholas J. Chrissotimos g/1
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UNITED STATES y,
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NUCLEAR REGUL ATORY COMMISSION
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- f Jocket Nos.:
50-254 FEB o8 ;p-7 50-265 tiEMORANDUM FOR:
Thomas Novak, Assistant Director for Operating Reactors i
Division of Licensing FROM:
James P. Knight, Assistant Director for Components and Structures Engineering Division of En'gineering
SUBJECT:
QUAD-CITIES STATION UNITS 1 AND 2 FUEL STORAGE-
~
MODIFICATION TAC. N0 43759 AND 43760 Plant Name:
Quad-Cities Station Units 1 and 2 Docket Nos.:
50-254 and 50-265 License Nos.:
DPR-29 and DPR-30 Responsible Branch and Project Manager:
ORB!2, R. Bevan Description of Task: Spent Fuel Storage Modification Review Status:
SER Complete
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The Structural Engi'neering Branch has reviewed the structural aspects of the information submitted by Comonwealth Edison Company regarding Quad-Cities Station Units 1 and 2 Fuel Storage Modification.
We conclude that the proposed spent fuel storage modification is acceptable.
Our Safety Evaluation Report is enclosed.
of the Structural Engineering Branch.The enclosure was. prepared by Owen Rothberg
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y James P. Knight,. Assistant Director' for Components and Structures Engineering Division of Engineering
Enclosure:
As stated cc:
R. Vollmer F. Schauer 0
P. Kuo T. Ippolito g'
hV R. Beven t
O. Rothberg 7,Q0 g
CONTACT:
- 0. Rothberg, SEB, x27864 C
ENCLOSURE (o
COMMONWEALTH EDISON COMPANY QUAD-CITIES STATION UNITS 1 AND 2 DOCKET NUMBERS 50-254 AND 50-265 LICENSE NUMBERS DPR-29 AND DPR-30 By letter. dated P. arch 26, 1981, Commonwealth Edison Company requested a change to Operating License Nos. DPR-29 and DPR-30 and Appendix A Technical Specifi-cations. The proposed modification concerns increasing the storage capacity?
in the spent fuel pools from 2920 space to 7684 storage spaces. High density fuel storage racks, containing Boraflex, a neutron absorbing material, will extend fuel storage capability through about the year 2000. At that time the ability to accommodate an emergency full core discharge will be lost.
Quad-Cities Units 1 and 2 each possess fuel storage pools 33' wide x 41' long.
Unit 1 pool will contain 19,high density fuel racks in 7 different module sizes -
with a total of 3714 storage locations while Unit 2 pool will contain 39'70 storage cells arranged in 20 racks with 6 different module sizes in this pool.
All modules are free standing, i.e., they are not anchored to the pool walls.
The minimum gap between adjacent racks is 3.0" at all locations and between
, the racks and the fuel pool walls is 9".
Due to these gaps, the
- possibility of inter-rack impact, or rack collision with pool wall hardware during the postulated ground seismic motion is precluded.
The racks will be constructed from ASTM 240 - 304, austenitic steel sheet material, ASTM 204 - 304 austenitic steel plate material, and ASTM 182 - F304 austenitic steel forgoing material. A typical module contains storage cells I
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which have 6" minimum internal cross-sectional opening.
Skip welding at the top ensures proper venting of the sandsiched space in the sub-elements which
' make up the fuel racks.
The rack assembly is typically supported on four plate type supports. The supports ' elevate' the module base plate 6.5" above the pool floor level, thus creating the water plenum for coolant flow.
Further details of the spent fuel pool racks are illustrated in the licensee's submittals.
STRUCTURAL AND MECHANICAL The design of the racks, fabrication, and installation criteria; the structural k-design and analysis procedures for all loadings, including seismic and impact loadings; the load combinations; the structural acceptance criteria; the quality assurance requirements for design, and applicable industry codes were all reviewed in accordance with the applicable portions of the current -
"0T Pcsition for Review and Acceptance of Spent Fuel Pool Storage and Handling Applications", dated April.1978, including revisions, dated Januray,1979.
i For the design of the spent fuel modules, two sets of criteria were to be satisfied. The first criteria ensures that adjacent racks will not impact during the SSE, assumming the lower bound value of the pool surface friction coefficient.
It is also required in this criteria that the factors of safety against tilting are met (1.5 for OBE and 1.1 for SSE). The second criteria ensures that loading combinations and stress allowables are in
(.x accordance with Section III, Subsection NF of the ASME 1980 Edition. The
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basic material allowables, fabrications, installations and quality control of the modules are, also, conform with the same code. The loading con-
'sidered in the analysis involves dead loads, live loads, thermal loading, and seismic loadings (OBE or SSE). Additional analysgs were performed to evalua,te the,effect of fuel assembly drop accident on the racks on the fuel pool liner and the fuel handling crane uplift accident.
A dynamic model consisting of beams, gaps, springs, dampers and inertia coupling representing fluid coupling between rack and assemblies, and between rack and adjacent racks was used to predict the maximum sliding distance and seismic forces during design earthquake. These forces were then used to predict the seismic stresses and displacements.
The coefficient of friction between the stainless steel liner and the racks leveling legs used in the analysis was chosen based on the information provided in a report tyjE. Rabinowicz of Massachusetts Institute of Technology entitled " Friction Coefficients of Water Lubrication Stainless Steel for a Spent Fuel Rack Facility" dated November 5, 1976. The result of this analysis indicates that although i
the proposed racks which are free-standing may slide towards each other during SSE, sufficient gaps are provided between the models' and the models and the pool walls such that the inter-rack impact, or the' rack collision with other pool walls is precluded.
The postulated assembly drop was considered in the analysis of the racks.
'Two postulated drops were analyzed.
The first drop is a straight drop l
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of a fuel assembly dropping from a maximum of 36" above the storage location and impacting the base. The sec6nd drop involves a fuel assembly dropping from a maximum of 36" above the rack and hits top of the rack.
In both cases, the impact energy is dissipated by local yielding,. however, the sub-criticality of the fuel arrays is not violated.
The effect of postulated stuck fuel assembly due to the attempted withdraw 1'was considered and the damage if any was required to be limited to the region above the active fuel elements.
The fuel pool concrete and liner were evaluated for the additional loads imposed by the new racks. And it was concluded that the structural members of the fuel pools are adequate to withstand the additional loads imposed by the new racks.
EVALUATION AND CONCLUSION The analysis, design, fabrication, and criteria for establishing installation procedures of the proposed new spent fuel racks are in confomance with accepted codes, standards and criteria.
The structural design and analysis --
procedures for all loadings, including seismic, thermal, and impact loading; the acceptance criteria foi the appropriate loading conditions and combinations; and the applicable industry codes are in accordance with appropriate sections of the NRC Staff "0T Posit ~ ion for Review and Acceptance of Spent Fuel Storage and Handling Applications".
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Allowable stress limits for the combined loading conditions are in accordance with the ASME Code, App. XVII. Yield stress values at the appropriate temper-ature were obtained from Section III of the ASME Code. The quality assurance and criteria for the materials, fabrication and installation of the new racks are in accordance with the accepted requirements of the ASME Code.
The effects of the additional loads on the existing pool structure due to the new fuel racks, existing fuel racks, and equipment have been examined.
The pool structural integrity is assured by conformance with the Standard Review Plan Section 3.8.4.
Results of the seismic and structural analyses indicate that the racks are capable of withstanding the loads associated with all design loading C
conditions. Also, impact due to fuel assembly / cell interaction has been considered, and will result in no damage to the racks or fuel assemblies.
Results of the dropped fuel assembly analyses show that local rack deformation will occur, but indicate that cornputed stresses meet the l
applicable allowables and that the integrity of the racks is maintained.. _.
I Results of the dropped heavy loads over the protective pool cover indicate that although local damage and plastic deformation may occur, the overall structural integrity of the cover is maintained and is.within the acceptable
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limits.
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Page 6 of Enclosure Results of the stuck fuel assembly analysis show that the stress is below those allowed for the applicable loading combinations.
We find that the subject modification proposed by the. licensee is acceptable _
and satisfies the applicable requirements of the General Design Criteria 2, 4, 61," and 62' of 10 CFR, Part 50, Appendix A.
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1 6.
STRUCTURAL ANALYSIS The purpose of this section is to demonstrate the structural adequacy of the spent fuel rack design under normal and accident loading conditions.
The results show that the high-density spent fuel racks are structurally adequate to resist the postulated stress combinations associated with normal and accident conditions.
6.1 Anal'ysis O'utline The spent fuel storage racks are Seismic Category.I equipment.
Thus, they are required to remain functional during and af ter an SSE (Safe Shutdown Earthquake).1 As noted previously, these racks are neither anchored to the pool floor, nor are they attached to the side walls.
The individual rack modules are not interconnected.
Further-more, a particular rack may be completely loaded with fuel assemblies (which corresponds to greatest rack inertia), or it may be partially loaded so as to produce maximum geometric eccentricity in the struc-ture.
The coefficient of friction,V, between the supports and pool floor is another indeterminate factor.
According to Rabinowicz,2 the
~
results of 199 tests performed on austenitic stainless plates sub-merged in water show a mean value of u to be 0.503 with a standard deviation of 0.125.
The upper and lower bounds ( 2 c) are thus 0.753 and 0.* 53, respectively.
Two separate analyses are performed for this 2
rack assembly with values of y equal to 0.2 (lower limit), and 0.8, respectively.
In summary, the following six separate analyses are performed:
1.
Fully loaded rack (all storage locations occupied),
q I
u = 0.8 ( p = coefficient of friction).
2.
Fully loaded rack, y = 0.2.
3.
Half-loaded rack to produce maximum geometric asymmetry about the major dimension of the rectangular rack, p = 0.8.
4.
Half-loaded rack to produce maximum geometric asymmetry about the major dimension of the rectangular rack, p = 0.2 5.
Half-loaded rack to produce maximum loading asymmetry about a diagonal, y = 0.8.
6-1
6.
Half-loaded rack to ;;oduce maximum loading asymmetry about a
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diagonal, y = 0.2.
The method of analysis employed is the time history method.
The ground acceleration data are from the original plant design as
' reflected in the FSAR.
The object of the seismic analysis is to determine the structural response. (stresses, deformation, rigid body motion, etc.) due to simultaneous application of the three orthogonal excitations.
- Thus, recourse to approximate statistical summation techniques such as SRSS 3
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method is avoided and the dependability of computed results is ensured.
The seismic analysis is performed in four steps; namely 1.
Development of nonlinear dynamic model consisting of beam, gap, spring, damper, and inertia coupling ele-ments.
(u 2.
Derivation and computation of element stiffnesses l
using a sophisticated elastostatic model.
3.
Layout of the equations of
- motion, and inertial decoupling and solution of the equations using the 4
" component element time integration" procedure to determine node and element forces and displacement _of l
nodes.
4.
Computation of the detailed stress field in the rack structure, using the detailed elastostatic model, from the nodal forces calculated in Step III above.
Deter-mine if the stress and displacement limits (given in Section 6.5) are satisfied.
A brief description of the dynamic model now follows.
6-2
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6.2 Fuel Rack - Fuel Assembly Model 6.2.1 Assumptions The fuel rack metal structure is represented by five lumped a.
masses connected by appropriate elastic springs.
(Refer to Figure 6.1).
The spring rates simulate the elastic behavior
, of the fuel rack as a beamlike structure.
b.
The fuel assemblies are represented by five lumped masses located, relative to the rack, in a manner wh'ich simulat[s either full or partially filled conditions.
c.
The local flexibility of the rack-support interface is 4
modeled conservatively in the analysis, d.
The rack base support may slide or lift off the pool floor.
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The pool floor is assumed to have known time history ground e.
accelerations in three orthogonal directions.
f.
Fluid coupling between rack and assemblies, and between rack and adjacent racks is simulated by introducing appropriate inertial coupling into the system kinetic energy.
g.
Potential impacts between rack and assemblies are accounted for by appropriate spring gap connectors between masses involved.
h.
Fluid damping between rack and assemblies, and between rack 4
and adjacent rack is conservatively neglected.
i.
The supports are modeled as extensional elements for dynamic analysis.
The bottom of a support leg is attached to a frictional spring as described in Section 6.2.2.
The cross section properties of the support beams are derived and used
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in the final computations to determine support leg stresses.
6-3
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The effect of sloshing can be shown to be negligible at the 4
bottom of a pool and is hence neglected.
,6.2.2 Model Description The absolute degrees of freedom associated with each of the mass locations i, i* are as follows (see Figure 6.1):
Table 6'.1 Degrees of Freedom Location Displacement Rotation u
u O
0 0
4 (Note) u, y
z x
y z
1 py p2 P3 94 95 96 1*
Point is assumed fixed to base at IB,YB, Z=0 2
P7 Pg 911 912 2*
p8 P10 3
p13 p15 917 918
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3*
pl4 P16 923 924 4
Pg P21 i
4*
P20 P22 5
p25 P27 P32 929 930 931
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5*
p26 P28 Thus, there are 32 degrees of freedom in the system. Note that elastic motion of the rack in extension is represented by generalized
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coordinates p3 and P32 This is due to the relatively high axial rigidity of the rack.
Torsional motion of the rack relative to its base is governed by q31 The members joining nodes 1 to 2, 2 to 3, etc., are beam elements with deflection due to bending and shear capability (see Reference 4, I
pp. 156-161).
The elements of the stiffness matrix of these beam ele-ments are readily computed if the ef fective flexure modulus, torsion modulus, etc., for the rack structure are known.
These coefficients follow from the elastostatic model as described later.
The node
~
points i (i = 1,2.. 5) denote the fuel rack mass at the 5 elevations.
The node points i* (i* =
1,2.. 5) denote the cumulative mass for all 6-4 j
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the fuel assemblies distributed at 5 elevations.
Referring to the
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General Electric specification,5 the bending and torsional stif fnesses of the fuel assembly (channeled or unchanneled) are several orders of magnitude smaller than the stiffnesses of the rack beam elements.
Hence, it is reasonable to neglect the spring elements joining these
' lumped masses.
In order to demonstrate that fuel assembly structural springs can be disregarded to produce conservative results, the case (refer to section 6.1) which yields maximum rack primary stress is also rua with. beam springs connecting fuel assembly lumped masses.
The nodes i* are located at I
=IB, Y "YB in the global coordinate system shown in Figure 6.1.
The coordinates (IB, YB) are determined by the center-of-mass of the ' set of fu'l assemblies.
For a completel'y e
loaded rack, IB"YB = 0.
6.2.3 Fluid Coupling An effect of somh significance requiring careful modeling is'the so-called " fluid coupling ef fect. "
If one body of mass mi vibrates adjacent to another body (mass m2), and both bodies are submerged in a frictionless fluid medium, then the Newton's equation of motion for the two bodies have the form 5-M E
= applied forces on mass mi (mi + M11) 1 12 2
51 + (m2 + M22) E2 = applied forces on mass M2
-M21 M11, M12s M21, and M22 are fluid coupling coefficients which depend on the shapes of the two bodies, their relative disposition; etc.
Fritz gives data for M j for various body shape and arrangements.
It is to i
l be noted that the above equation indicates that effect of the fluid is to add a certain amount of mass to the body (Mil to body 1), and an external force which is proportional to the acceleration of the adjacent body (mass m2).
Thus, the acceleration of one body af fects the force field on another.
This fo,rce is a strong function of the interbody gap, reaching large values for very small gaps.
This inertial coupling is called fluid coupling.
It has an important ef fect in rack dynamics.
The lateral motion of a fuel assembly inside the storage location will encounter this effect.
So will the motion of a rack adjacent to another rack.
These effects are included in the equations of motion.
The fluid coupling is be tween nodes i and i* (i =
2,3..
- 5) in Figure 6.1.
Furthermore, nodal masses i contain 6-5
coupling terms which model the effect of fluid in the gaps between adjacent racks.
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Finally, fluid virtual mass is included in vertical direction vibration equations of the rack; virtual inertia is added to the
, governing equations corresponding to rotational degrees of freedom, such as q4, q5' 9 ' 911, etc.
6 6.2.4 Damping In reality, damping of the rack motion arises from material hysteresis (material damping),
relative intercomponept motion in structures (structural damping),
and fluid drag effects (fluid damping). The fluid damping acts on the i and i* nodal masses.
In the analysis, a maximum of it structural damping is imposed on elements of' the rack structure during SSE seismic simulations.
This is in accord-ance with NRC guidelines.7 Material and fluid damping are conservatively neglected.
6.2.5 Impact The fuel assembly nodes i* will impact the corresponding struc-tural mass node i.
To simulate this impact, 4 impact springs around each fuel assembly node are provided (see Figure 6.2).
The fluid dampets are also provided in parallel with the springs.
The spring constant of the impact springs is assumed equal to the local stiffness of the vertical panel computed by evaluating the deflection of a 6-inch-diameter circular plate (0.075-inch) uniformly loaded and built in around the edge.
The spring constant calculated in this manner should provide an upper bound on the local stiffness of the structure.
6.2.6 Assembly of the Dynamic Model l
The dynamic model of the rack, rack base plus supports, and in-ternal fuel assemblies, is modelled for the general three-dimensional (3-D) motion simulation, by five lumped masses and inertia nodes for
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the rack, base, and supports, and by five lu= ped masses for the assemblage of fuel assemblies.
To simulate the connectivity and the elasticity of the configuration, a total of 37 linear spring dampers, 6-6 l
5 20 nonlinear gap elements, and 18 nonlinear friction elements are used.
A summary of spring-damper, gap, and friction elements with their connectivity and purpose is presented in Table 6.2.
If we restrict the simulation model'to two dimensions (one hori-zontal motion plus vertical motion, for example) for the purposes of simulated model clarification only, then a descriptive ' model of the structure which, includes all necessary spring, gap, and friction ele-ments is shown in Figure 6.3.
The beam springs K r KB at each level, l7 s
structural beam,4 are which represent ~ a rack segment treated as a located in Table 6.2 as linear springs 2, 3, 6, 7, 10, 11, 14, and 15,.
The extensional spring K, which simulates the lowest elastic moti6n E
of the rack in extension relative to the rack base, is given by linear.
spring 37 in Table 6.2.
The remaining spring-dampers either have zero coefficients (fluid damping is neglected), or do not enter into the two-dimensional ( 2-D) motion shown in Figure 6.3.-
The rack mass and
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active in rack bending, is apportioned to the five levels of
- inertia, rack mass; the rack mass active for vertical motions is apportioned to
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locations 1 and 5 in the ratio 2 to 1.
The mass and inertia of the rack base and the support legs is concentrated at node 1.
impacts between fuel assemblies and rack show up in the gap The elements, having local stif fness K, in Figure 6.3.
In Table 6.2, I
these elements are gap' elements 3, 4, 7, 8, 15, 16, 19, and 20.
The support leg spring rates Kg are modelled by elements 9,10 in Table 6.2 Note that the local elasticity of the concrete floor for the 2-D case.
7 To simulate sliding potential, friction elements 2 is included in Ks.
plus 8 and 4 plus 6 (Table 6.2) are shown in Figure 6.3.
The local spring rates Kg reflect the lateral elasticity of the support legs.
reflect the rota-Finally, the support rotational friction springs K R, tional elasticity of the foundation.
The nonlinearity of these springs (friction elements 9 plus 15 and 11 plus 13 in Table 6. 2) reflects the edgin.g limitation imposed on the base of the rack support legs.
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l Table 6. 2 Numbering System for Springs, Gap
~
Elements, Friction Elements I.
Spring Dampers (37 total)
Number Node Location Description 1
1-2 I-Z rack shear spring 2
1-2 Y-Z rack shear 3
1-2 Y-Z rack bending spring 4
1-2 1-Z rack bending 5
2-3 I-Z rack shear 6
2-3 T-Z 7
2-3 Y-Z rack bending 8
2-3 I-Z 9
3-4 I-Z rack shear 10 3-4 T-Z 11 3-4 Y-Z rack bending 12 3-4 I-Z 13 4-5 I-Z rack shear 14 4-5 Y-Z 15 4-5 Y-Z rack beqding 16 4-5 I-Z 17 1-5 Rack torsion spring 18*
1 Fluid damping of rack in torsion 19*
1 Fluid damping of rack in I direction 20*
1 Rack fluid damper in Y direction 21*
2 I direction rack fluid damper 22*
2 Y direction rack fluid damper 23*
3 I direction rack fluid damper 24*
3 Y direction rack fluid damper 25*
4 I direction rack fluid damper 26*
4 Y direction rack fluid damper 27*
5 I direction rack fluid damper 28*
5 Y direction rack fluid damper 29*
2,2*
I rack / fuel assembly damper 30*
2,2*
Y rack / fuel assembly damper 31*
3,3*
I rack / fuel assembly damper 32*
3,3*
Y rack / fuel assembly damper 33*
4,4*
I rack / fuel assembly damper 34*
4,4*
Y rack / fuel assembly damper
(
- Note: Dampers 18-36 assumed inactive.
6-8
Table 6.2 (continued)
~
Number Node Location Description 35*
5,5*
I rack / fuel assembly damper 36*
5,5*
Y rack / fuel assembly damper 37 1-5 Z rack extensional spring
- Note: Dampers 18-36 assumed inactive.
t II.
Nonlinear Springs (Gap Elements) (20 total)
Number Node Location Description 1
2,2*
I rack / fuel assembly impact spring 2
2,2*
I rack / fuel assembly impact 3
2,2*
Y rack / fuel assembly impact -
4 2,2*
Y rack / fuel assembly impact 5
3,3*
I rack / fuel assembly impact 6
3,3*
I rack / fuel assembly impact 7
3,3*
Y rack / fuel assembly impact 9
3,3*
Y rack / fuel assembly impact 9
Support S1 Z compression spring 10 Support S2_
Z compression spring 11 Support S3 2 compression spring 12 Support S4 2 compression spring 13 4,4*
I rack / fuel assembly impact spring 14 4,4*
I rack / fuel assembly impact spring
[
15 4,4*
Y rack / fuel assembly impact spring
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16 4,4*
Y rack / fuel assembly impact spring 17 5,5*
I rack / fuel assembly impact spring 18 5,5*
I rack / fuel assembly impact spring 19 5,5*
Y rack / fuel assembly impact spring 20 5,5*
Y rack / fuel assembly impact spring III.
Friction Elements (16 total)
Number Node Location Description 1
Support S1 I direction support friction i
2 Support S1 Y direction friction 3
Support 52 I direction friction 4
Support S2 Y direction friction 5
Support S3 I direction friction 6
Support S3 Y direction friction 7
Support S4 I direction friction 8
Support S4 Y direction friction 9
S1 1 Floor Moment i
10 S1 Y Floor Moment 11 52 I Floor Moment 12 S2 Y Floor Moment 13 S3 I Floor Moment 14 S3 Y Floor Moment 15 S4 I Floor Moment 16 S4 Y Floor Moment 6-9
For the 3-D simulation, carried out in detail for this analysis,
(
additional springs and support elements (listed in Table 6.2), are s
included in the model.
Coupling between the two horizontal seismic motions is provided by the of fset of the fuel assembly group centroid which causes the rotation of the entire rack.
The potential exists for the assemblage to be supported on 1 to 4 rack supports during any instant of a complex 3-D seismic event.
All of these potential events may be simulated during a 3-D motion and have been observed in the results.
A brief description of the elastostatic model follows.
This detailed model is used to obtain overall beam stiffness formulae for the rack dynamic model, and to determine detailed stress distributions,
in the rack from a knowledge of the results of the time history analysis.
6.3 Stress Analysis 6.3.1 Stiffness Characteristics The fuel rack is a multicell, folded-plate structure which has what is colloquially called an " egg-crate" configuration.
This type of construction is very similar to the so-called " stressed-skin" con-struction of ribs, spars, and cover plates which are widely used in aircraft construction.
Techniques developed in the field of aircraft structural analysis are utilized herein to find the stresses and deformations in such structures.
These methods have been thoroughly tested and their reliability has been documented in a number of publications.8-12 l
Figure 6.4 shows two cross sections of the fuel rack which is modeled as a rectangular network of plates interconnected along nodal lines shown as points in Figure 6.1.
An arbitrary load with compo-nents Fri, Fy, Fzi acts at an arbitrary elevation on one of the nodal i
lines.
We find the displacements and stresses due to such a typical load according to the stressed-skin model as follows.
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6-10 l
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The torsional deformations are solved for by using the classical theory of torsion for multicelled, thin-walled, cross sections.13 The bending deformation is found by using the theory of shear l2 flow wherein all axial stresses are carried by the effective flanges
.(or stringers) formed by the intersections of the plates and all transverse shears are carried by the plates modeled as shear panels.
From a knowledge of the shear flows, the bending and torsional deformations, ft is possible to provide a set of influence functions or the following section properties for the fuel rack as a whole:
(EI)eq = Bending rigidity (in two places)
(GJ),q = Torsional rigidity (AE),q = Extensional rigidity ks
= Shear deformation coefficient such properties are used for the dynamic analysis of seismic loads and serve to establish values for the spring rates of the 4
elastic beam elements representing each rack section.
6.3.2 Combined Stresses and Corner Displacements The cross-sectional properties and the Timoshenko shear correc-tion factor calculated in the previous section are fed into a dynamic analysis of the system shown in Figure 6.5 with a specified ground motion simulating earthquake loading.
From the dynamic analysis, the Mx, M, Mz) act as shown in Figure 6.6 stress resultants (Fx, Fy, Fze y
are computed for a large number of ' times t = at, 24t, etc.,
at a selected number of cross sections.
The displacements (Ux, Dy, U ) at z
selected nodal points on the z axis are also provided by the dynamic analysis as well as rotations (e,e,e) of the cross sections atl4 x
y z
the nodes.
Figure 6.7 shows a typical subdivision of the structure into ele-ments, nodes, and sections.
The stresses are calculated at all 6-11
sections and the displacements at all four corners of the rack are calculated at these elevations.
Since the axial stress varies linearly over the cross section and l4
' achieves its extreme values at one of the four corners of the rack, the shear stresses due to torsional loads (M ) ach.ieve their extreme z
values near the middle of each side. The shear stresses due to lateral forces (Fx, Fy), will achieve their extreme values at the center of the cross section or at the middle of each side.
Thus, candidates for the most critical point on any section will be the points labelled 1 through 9 in Figure 6.8.
The expression for the combined stress and kinematic displacement for each of these points is written out.
Similarly, the stresses in the support legs are evaluated.
A validated Joseph Oat Corp.
proprietary computer program 4
"EGELAST" computes the' stresses at the candidate points in each level.
It sorts out the most stressed location in space as well as time.
The highest stress, and maximum kinematic displacement are thus readily found.
6.4 Time Intecration of the Ecuations of Motion Having assembled the structural model, the dynamic equations of mction corresponding to each degree of freedom can be written by usiag Newton's second law of motion; or using Lagrange's equation.
For example, the motion of node 2 in y-direction (governed by the gener-alized coordinate pg is written as follows:
The inertial mass is l4 "22 + A212 +
211 where m is the mass of node 2 for y-directional motion.
22 is the fluid coupling mass due to interaction with node 2*,
and l
A212 is the fluid coupling mass due to interaction of node 2 with the B
211 reference frame (interaction between adjacent racks).
6-12
=
Hence, Newton's law gives
,(.
0 (m
+
A B
I A
+
+ B 22 212 211 9
+
212 10 212 9
where 09 represents all the beam spring and damper forces on node 2, and A212 is the cross term fluid coupling effect of node 2*; B212 is the cross term fluid coupling effect of the adjacent racks.
u represents the ground acceleration.
Let
~"
99=P9 - u, q10 " P10 That is, q9 is the relative displacement of node 2 in x-direction with.
respect to the ground.
Substituting in the above equation, and rear-ranging, we have U10 " 09 I"22 + A222 + B211 + A212 +
I 9+A212 I"22 + A222 + B211
- B I
212 A similar equation for each one of the 32 degrees of freedom can be written.
The system of equations can be represented in matrix notation as:
[M] {4} = [Q) + {G}
where the vector [Q lis a
function of nodal displacement and velocities, and { G } depends on the coupling inertias and the ground acceleration.
Premultiplying above equation by I M F1 renders "the resulting equations uncoupled in mass.
We have:
~1
{y} = [M)
(Q) + [M) -
{G}
The generalized force 0,
which contains the effects of all 9
spring elements acting on node 2 in the " direction" of coordinate q9 (the relative displacement of node 2 in the y direction), can easily be obtained from a free body analysis of node 2.
For example, in the 6-13
are obtained from 2-D model shown in Figure 6.3, contributions to 09
[.
the two shear springs of the rack structure, and the two impact springs which couple node 2* and node 2.
Since each of these four spring elements contain couplings with other component deformations through the spring force-deformation relations, considerable static coupling of the complete set of equations results.
The level of static coupling of the equations further increases when 3-D motions are considered due to the inclusion of rack torsion and general fuel assembly group centroid offset.
For example, referring to Figure 6.3, a 2-D simulation introduces static coupling between coordinates 2, 9, and 15 in the expression for 0; this coupling comes from the shear springs simulating the rack,
9 elasticity which have constitutive relations of the form lFl=K l(99 - 92)l, Ks l(915 - 99 )l.
Further, the impact springs s
introduce two additional forces having constitutive equations of the l(q9 - glo)l.
Of course, at any instant, these forces 4
form lFl = K I may be zero if the local gap is open.
The local gap depends on the
(
current value q9-q10; It should be noted that in the numerical simulations run to verify structural integrity during a seismic event, all elements of the fuel assemblies are assumed to move in' phase.
This will provide maximum impact force level, and hence induce additional conservatism in the time history analysis.
This equation set is mass uncoupled, displacement coupled; and is ideally suited for numerical solution,using the central difference scheme.
The computer program, named "DYNAHIS" developed by General Electric Company, performs this task in an ef ficient manner.4 l
i l
Having determined the internal forces as a function of time, the computer program "EGELAST" computes the detailed stress and displace-field for the rack structure as described in the preceding see-ment tion.
6-14
,~
6.5 Structural Acceptance Criteria
~
There are two sets of criteria to be satisfied by the rack modules:
(a) Kinematic Criterion: This criterion seeks to ensure that adjacent racks will not impact during SSE (condition E'14),
assuming the lower bound value of the pool floor surface friction coefficient.
It is further required that the f actors of safety against tiltingl5 are met (1.5 for OBE, 1.1 for SSE).
~
(b) Stress Limits (1)
The stress limits of the ASME Code,Section III, Subsection -
NF, 1980 Edition were chosen to be met, since this Code provides the most consistent set of limits for various stress types, and
~
various loading conditions.
The following loading casesl4 have been analyzed.
SRP Designation ASME Designation (i)
D+L Level A (normal condition)
(ii)
D+L+E Level B (upset condition)
(iii)
D+L+T No ASME designation.
Primary o
membrane plus bending stress required to be limited to lesser of 2 S
- and Su*
y (iv)
D+L+To+E No ASME designation.
Stress limit same as (iii) above (v)
D+L+Ta+E No ASME designation.
Stress limit same as above (vi)
D+L+Ta + E' Level D (faulted condition) where D = Dead weight induced stresses L = Live load induced stresses; in this case stresses developed during lifting f
- Sy: Yield stress of the material; Su: ultimate stress.
6-15 l
l
E = OBE (time history loading)
E'
= SSE To = Stresses due to asymmetric heat emission from the fuel assemblies Ta = Thermal stresses due to accidents The conditions T and To cause local thermal stresses to be a
produced.
The worst situation will be obtained when an isolated stor-age location has a fuel assembly which is generating heat at the maxi-mum postulated rate.
The su'rrounding storage locations are assumed to contain no fuel.
Furthermore, the loaded storage location is assumed, to have unchanneled fuel.
Thus, the heated water makes unobstructed contact with the inside of the storage walls, thereby producing maximum possible temperature dif ference between the adjacent cells. ~
The secondary stresses thus produced are limited to the body of the rack; that is, the support legs do not experience the secondary (thermal) stresses.
(2)
Basic Data: The following data on the physical properties of the rack material are obtained from the ASME Code,Section III, i
appendices.
Table 6.3 Physical Property Data' Property Young's field Ultimate Allowable Modulus Strength Strength Stress e 2000F e 2000F 62000F e 2000F 4
y Su 5
E S
Value 28.3 x 106 25 KSI 71 KSI 17.8 KSI psi Section III Table Table Table Table Reference I-6.0 I-2.2 I-3.2 I-7.2
- Evaluated at 200 F.
This temperature is higher than the pool water 0
bulk temperature under any of the loading conditions under consideration.
6-16
(3)
Stress limits for normal and upset, and faulted conditions:
The following limits are obtained from NF-3230 in conjunction with Appendix XVII as modified by the NRC Regulatory Guide 1.124.16
( 3.1)
Nor=al and upset conditions (level A or level B):
(i) Allowable stress in tension on'a net section = Ft" 0.6 Sy or Fe = (0.6) (25000) = 15000 psi Ft is equivalent to primary membrane stresses (ii)
On the gross section, allowable stress in shear is Fy = 0.4 Sy (0.4) (25000) = 10000 psi
=
(iii)
Allowable stress in compression, Fa
~
.l - (h) 2C2 g
e y
+
8C c
where (2 2 )b E
Ce =
= 147.61 3
Y Substituting numbers, we obtain, for both support leg and
" egg-crate" region:
Fa = 15000 psi (iv)
Maximum bending stress at the outermost fiber due to l
flexure about one plane of symmetry:
Fb = 0.60 Sy = 15000 psi l
(v)
Combined flexure and compression:
f f
bCmx bx, Cmy by < 1 F,
DF DF x 3x y 3y 6-17
l where
(
f:
Direct compressive stress in the section a
fbx:
Maximum flexural stress x-axis Fby:
Maximum flexural stress y-axis Cmx = Cmy = 0.85 Dx = 1 SA-Fe'x f,
= 1 Fg Dy where 2
12r E F,,x =
2
/ki \\
b 2 31 l
(#b/
(vi) Combined flexure and compression (or tension)
(..
f
- a bx
- by <l.0 0.6 5
,F F
3x 3y The above requirement should be met for both direct tension or compression case.
(3.2)
Faulted Condition:
F-1370 (Section III, Appendix F), states that the limits for the faulted condition are 1.2 times the corresponding limits for normal conditi'on.
Thus, the multiplication factor is 2 00 Factor =
(1.2)
= 2.0 (3.3)
Thermal Stresses:
There are no stress limits for thermal (self-limiting) stresses in Class 3-NF Structures for linear-type supports.
However, the range of primary and secondary stress intensity is required to be limited to 3 Sm in the manner of Class 1 6-18
components; Sm is the allowable stress intensity of the rack
{
material at the maximum operating temperature.
\\
6.6 Accidents Associated with Rack Integrity In addition to the ground motion analyses, the following mechani-cal loads have been analyzed:
, Dropped Fuel Accident I a.
A fuel assembly (weight 600 pounds) dropping from 36 inches above a storage location and impacting the base.
Local failure of the base plate is acceptable ~; however, a'
substantial impact with the pool liner is not acceptable.
The subcriticality of the adjacent fuel assemblies is not to.
be violated.
b.
Dropped Fuel ~ Accident II one fuel assembly dropping from 36 inches above the rack and hitting the top of the rack.
Permanent deformation of the rack is acceptable, but is required to be limited to the
~~
top region such that the rack cross-sectional geometry at the level of the top of the active fuel (and below) is not altered.
c.
Jammed Fuel-Handling Eculpment and Horizontal Force A 2000-pound uplift force and a 1000-pound horizontal force are applied at the top of the rack at the " weakest" storage
~
location; the force is assumed to be applied on one wall of the storage cell boundary as an upward shear force.
The damage, if any, is required to be limited to the region above the top of the active-fuel.
The above loading conditions were analyzed to determine an upper bound on the plastic deformation zones.
For the above conditions, it has been shown that the plastic deformation is limited to the rack structure well removed from the active fuel regions.
Thus, the sub-criticality of the fuel arrays is not modified or violated.
6-19
6.7 Results The input time history accelerations for horizontal motion were prepared by Sargent and Lundy engineers, and verified by NUS Corporation.
Vertical acceleration time history was developed by NUS Corporation.
Plots of the two time history motions may be found in Fig. 6.9 and Fig. 6.10 respectively.
These plots correspond to the Operating Basis Earthquake condition.
Since there are several rack module configurations (Figs. 2.1 and 2.2), it was decided to make an exhaustive analysis of one rack type.
We note that rack A is ar. above-average size module, and hence will produce above-average floor reaction and support stress levels.
Rack type A is also most numerous.
Hence rack A is chosen for performing" extensive analyses.
Appropriate simulations are also carried out for other limiting rack geometrics (e.g. tipping study for rack with low cross section to height aspect ratio, stress evaluations for the heaviest module, etc.).
To determine the magnitude of structural dampers, free lateral vibration plots of the top of rack A (in X and Y directions) for f ully loaded and empty conditions were developed. The dominant natural frequency of vibration thus evaluated enables computations of the linear structural dampers.
The percentage structural damping for SSE condition i s.
assu=ed to be it, and 4
modifications to the stiffness matrix to incorporate damping is based on the dominant frequency of 10 cps.
Having determined the damper characteristic data, the dynamic analysis of the rack module is performed using the computer program DYNAHIS.
Two equal components of the SSE horizontal acceleration are applied in two orthogonal directions concurrently with the vertical seismic acceleration.
Abstracted results for all six cases mentioned in Section 6.1 are reported in Table 6.4.] Table 6.5 gives the maximum values of stress factors Ri (i = 1,2,3,4,5,6).
The values given in the tables are the maximum values in time and space (all sections of the rack).
The various stress factors are listed below for convenience of reference.
I 6-20 1
~~
R:
Ratio of tensile stress on a net section to its allowable 1
OBE value R:
Ratio of gross shear on a net section to its allowable OBE 2
value R:
Ratio of net compressive stress to its allowable OBE value 3
for the section R:
Ratio of maximum bending stress in one plane to its 4
allowable value in OBE R5:
Combined flexure and compressive factor R:
Combined flexure and tension (or compression) _ factor 6
The allowable value of Ri (i
1,2,3,4,5,6) is 1 for OBE
=
condition, and is 2 for SSE condition (see Section 6.5).
~
The displacement and _ stress tables given herein are for the SSE condition.
It is noted that the maximum displacements are a fraction of the limiting value for inter-rack impact. (The maximum stress factors (Ri) are well below 2 in all cases, forallsections]
c
, Seismic simulations for the tipping conditions are carried out by v
increasing the horizontal SSE accelerations by 50%.15 The calculations indicate that the rack remains stable, and the gross of small motion theory. {Thus moveme.it remains within the limit the rack module is seen to satisfy both kinematic and stress criteria with 4
largemarginsofsafety.]
I Since there are a number of rack module geometries, it was necessary to make a large number of analyses to establish that the stress and kinematic criteria are satisfied for all cases.
Some bounding rack l
geometry / inertia shapes, which envelope actual rack shapes, were studied to obtain an upper bound on the actual rack response.
It is noted that all displacements and stresses are below the permissible values for SSE loading.
Since, the OBE loading is one-half that of the SSE, and the maximum stress factor, R, for SSE loading is only 1.682, the maximum stress factor for OBE loading is approximately 0.84.
~
Hence, the stresses are also acceptable for OBE loading conditions.
l l
l l
6-21 l
l
Case 3 for rack G has been analyzed using a horizontal seismic input j'
magnified by the factor 1.5.
Thus, the displacement results presented for this case indicate whether we have a 1.5 safety factor on tipping.
The displacement results presented for this case show no propensity for significant tipping to take place during a seismic event.
The tipping analysis was also used for the E rack corresponding to fuel assembly loading of case 3.
Results show again that no significant tipping occurs.
Note that the results of the stress tables (summarizing the R factors) for case 3 should be disregarded since the accelerations have been incr~ eased by the factor 1.5.
0.8, 0.2) were run for racks G and E Empty rack conditions ( 1:
=
(labeled as case 7 & 8 respectively in the tables).
Once again, large margins of safety against kinematic displacement and allowable stresses are indicated.
Tables 6.4 and 6.5 also present output for a hypothetical rack having the configuration of rack E,
but assuming that the maximum number of fuel assemblies is that of rack F.
Thus, we can infer from this analysis some indication of the structural integrity of rack F which contains 256 fuel assemblies.
Of interest is the fact that the maximum stress factor is only 1.65.
A similar analysis of welded joints in the rack also show comparable margins of safety.
6-22
[.
(D.
.D Table 6.4 Maximum I and Y Displacements and their Coincident Time Man.
Time Man.
Time Module Case X-Disp.
Instant Y-Disp.
' Instant No, p
(inch)**
.(sec)
(Inch)**
(sec)
Comments Type A
1 0.8 0.382 6.96 0.417 6.80 Fully loaded A
2 0.2 0.519 9.42 0.603 9.41 Fully loaded.
A 3
0.8 0.710 8.37 0.705 9.59 Half loaded A
4 0.2 0.504 9.71 0.706 9.72 Half loaded A
5 0.8 0.097 6.97 0.048 9.99 Half diagonal loaded i
i l-A 6
0.2 0.790 9.71 0.568 9.71 Half diagonal loaded E
1 0.8 0.812 7.22 0.744 7.17 Fully loaded E
2 0.2 0.638 9.41 0.757 9.41 Fully loaded E
3 1.47 10.01 1,48 10.01 Tipping study, case 3 loading E
4 0.2 0.896 9.71 0.34/.
9.40 Halt loaded E
5 0.8 0.499 7.35 0.448 5.90 Half diagonal loaded E
6 0.2 0.487 9.70 0.439 9.41 Half diagonal loaded E
7 0.8 0.298 9.79 0.292 9.47 Empty rack E
8 0.2 0.309 9.41 0.400 9.41 Empty rack
- u6 r
1 0.8 0.967 8.11 0.818 7.74 E rack section, F rack full inertla G
1 0.8 0.392 6.98 0.579 7.19 Fully loaded G
2 0.2 0.227 9.41 0.724 9.41 Fully loaded G
3 0.966 9.71 0.836 8.37 Tipping s,tudy, case 3 loading C
4 0.2 0.318 9.72 0.461 9.41 Half loaded G
5 0.8 0.348 4.69 0.485 6.91 Half diagonal loaded C
6 0.2 0.313 9.71 0.398 9.41 Half diagonal loaded G
7 3.8 0.097 8.36 0.058 8.53 Empty rack G
8 0.2 0.222 9.42 0.431 9.40, Empty rack a*These displacements include components due to deformation, sliding and tipping under SSE doading.
6-23
O, r'
_ ble 6.5 animum values of Stress ractors (Rg through R6I Module Case h3 Rg R$
R6 Commenta Type No.
p R1 R2 A
1 0.8 0.339 0.208 0.595 0.625 1.132 1.280 Fully loaded A
2 0.2 0.178 0.403 0.151 0.177 0.434 0.480 Fully I'onded A
3 0.8 0.179 0.170 0.432 0.355 0.631 0.716 Half leaded A
4 0.2 0.127 0.031 0.180 0.135 0.369 a.413 Half loaded A
5 0.8 0.161 0.145 0.382 0.333 0.670 g 0.764 Half diagonal loaded A
6 0.2 0.145 0.036 0.157 0.161 0.390 0.436 Half diagonal loaded E
1 0.8 0.827 0.396 0.705 0.705 1.552 1.682 Fully loaded E
2 0.2 0.159 0.043 0.127 0.122 0.338 0.373 rully loaded E
3 0.430 0.304 0.433 0.401 0.945 1.036 Tipping study, case 3 loading E
4 0.2 0.137 0.041 0.125 0.202 0.281 0.314 Half loaded E
5 0.8 0.266 0.203 0.392 0.363 0.758 0.862 Half diagonal loaded E
6 0.2 0.129 0.037 0.083 0.137 0.288 0.317 Half dlagonal loaded E
7 0.8 0.103 0.088 0.149 0.151 0.298 0.338 Empty rack E
8 0.2 0.040 0.010 0.026 0.023 0.078 0.084 Empty rack r
1 0.8 0.749 0.412 0.593 0.721 1.152 1.645 E rack section, r rack full Inertla G
1 0.8 0.506 0.298 0.592 0.469 1.016 1.118 Fully loaded G
2 0.2 0.152 0.044 0.109 0.132 0.287 0.311 rully loaded C
3 0.379 0.277 0.418 0.406 0.791 0.864 Tipping study, case 3 loading G
4 0.2 0.122 0.036 0.104 0.148 0.241 0.265 Half loaded G
5 0.8 0.250 0.247 0.399 0.285 0.581 0.644 Half diagonal loaded C
6 0.2 0.114 0.033 0,079 0.093 0.222 0.243 Half diagonal loaded C
7 0.8 0.103 0.068 0.153 0.101 0.216 0.245 Empty rack G
8 0.2 0.029 0.008 0.027 0.030 0.059 0.064 Empty rack l
l l
t 6-24 Ttt2
.~,
(.
REFERENCES TO SECTION 6 1.
" Seismic Design Classification,"
Rev. 3, 1978.
2.
" Friction Coefficients of Water Lubricated Stainless Steels for a Spent Fuel Rack Facility," by Prof. Ernest Rabinowicz, MIT, a report for Boston Edison Company, 1976.
2.
U.S.
Nuclear Regulatory Commission, Regulatory Guide 1.92,
" Combining Modal Responses and Spatial Components in Seismic Response Analysis," Rev. 1, February 1976.
4.
"The Component Element Me thod in Dynamics with Application to Earthquake and Vehicle Engineering" by S.
Levy and J.
P.
D.
Wilkinson, McGraw Hill, 1976.
5.
General Electric specification 22A5866, Rev.
1, Appendix II, "
" Fuel Assembly Structural Characteristics."
6.
R.
J.
- Fritz, "Th_e Effect of Liguids on the Dynamic Motions of Immersed Solids," Journal of Engineering for Industry, Trans. of the AS.%E, February 1972, pp. 167-172.
7.
USNRC Regulatory Guide 1.61, Damping Values for Seismic Design of Nuclear Power Plants, 1973.
8.
J. T. Oden, " Mechanics of Elastic Structures," McGraw-Hill, N.Y.,
1967.
9.
R.
M.
- Rivello,
" Theory and Analysis of Flight Structures,"
McGraw-Hill, N.Y., 1969.
10.
M.
F.
Rubinstein,
" Matrix Computer Analysis of Structures,"
l Prentice-Hall, Englewood Cliffs, N.J., 1966.
t l
11.
J.
S.
Przemienicki, " Theory of Matrix Structural Analysis," _
McGraw-Hill, N.Y., 1966.
12.
P.
Kuhn, " Stresses in Aircraft and Shell Structures," McGraw-Hill, N.Y., 1956.
13.
S.
P. Timoshenko and J. N. Goodier, " Theory of Elasticity,"
McGraw-Hill, N.Y., 1970, Chapter 10.
i 14.
U. S. Nuclear Regulatory Commission, Standard Review Plan, NUREG-4 75/087, Section 3.8.4, Rev. 1, 1981.
15.
U.S. Nuclear Regulatory Commission, Standard Review Plan, Section 3.8.5, Rev. 1, 1981.
16.
U.S.
Nuclear Regulatory Commission, Regulatory Guide 1.124,
" Design Limits and Loading Combinations for Class 1 Linear-Type Component Supports, November 1976.
6-25 I
REFERENCES TO SECTION 6 1.
" Seismic Design Classification,"
Rev. ~3, 1978.
" Friction Coef ficients of Water Lubricated Stainless Steels for a 2.
Spent Fuel Rack Facility," by Prof. Ernest Rabinowicz, MIT, a 'l,
for Boston Edison Company, 1976.
report 3.
U.S.
Nuclear Regulatory Commission, Regulatory Guide 1.92,
" Combining Modal Responses and Spatial Components in Seismic Response Analysis," Rev.
l', February 1976.
~.
"The Component Element Method in Dynamics with, Application to 4
Earthquake and Vehicle Engineering" by S.
Levy and J.
P.'D.
Wilkinson, McGraw Hill, 1976.
5.
General Electric specification 22A5866, Rev.
1, Appendix II,
" Fuel Assembly Structural Characteristics."
6.
R.
J. Fritz, "The Effect of Liguids on the Dynamic Motions of Immersed Solids," Journal of Engineering for Industry, Trans, of the ASME, February 1972, pp. 167-172.
(
USNRC Regulatory Guide 1.61, Damping Values for Seismic Design of
(
7.
Nuclear Power Plants, 1973.
J. T. Oden, " Mechanics of Elastic Structures," McGraw-Hill, N.Y.,
8.
1967.
9.
R.
M.
- Rivello,
" Theory and Analysis of Flight Structures,"
McGraw-Hill, N.Y., 1969.
10.
M.
F.
Rubinstein,
" Matrix Computer Analysis of Structures,"
Prentice-Hall, Englewood Cliffs, N.J., 1966.
S. Przemienicki, " Theory of Matrix Structural Analysis,'"
11.
J.
McGraw-Hill, N.Y., 1966.
12.
P.
Kuhn, " Stresses in Aircraft and Shell Structures," McGraw-
- Hill, N,Y., 1956.
S. P. Timoshenko and J. N. Goodier, " Theory of Elasticity,"
13.
McGraw-Hill, N.Y., 1970, Chapter 10.
U. S. Nuclear Regulatory Commission, Standard Review Plan, NOREG-14.
7, 0800, Section 3.8.4, Rev. 1, 1981.
U.S. Nuclear Regulatory Commission, Standard Review Plan, NUREG-15.
0800, Section 3.8.5, Rev. 1, 1981.
16.
U.S.
Nuclear Regulatory Commission, Regulatory Guide 1.124, j
" Design Limits and Loading Combinations for Class 1 Linear-Type
)
Component Supports, November 1976.
6-27
l Z
" a3 L
)
/
CO U PLIN G ELEMENTS TYPIC AL FU EL ASS EM B LY.
3 /
GROUP MASS H
TYPICAL FUEL RACK MASS FUEL R ACK B A SE 2
~
7_ A y 7
/
\\
l l
Ax
_L y ya 7-
_Y y
s
/
f.--+.--_./,X8 3 2 l
a i
n
,4 4.'r FUEL R ACK SUPPORT I
X XB, Ys - LOCATION OF CE N TROID O F FU EL ROD G ROUP M ASSES - RELATIVE TO CEN TER O F FU EL R A C K ni = UNIT VECTORS Figure 6.1 Dynamic Model
Y IMPACT n
SPRIN G S
~
1 1 1 ;
em
._..T
[.H MASS
{*
~
C.
5 '^[
t F LU ID DAM PERS RIGIO FR AM E X
I Figure 6.2 Impact Springs and Fluid Dampers
C,
- 5 4
WM 5
K,K,Urp.) N v
SeisEic h
WM g
Motions E
4 Z
~
b
' Fusi Assamldy Group Lamped Mass Y
g)
%s 1f h
WN 3
Rad Lunged Mass & laertin For Horizontal 0
Motions Urp4 2
NN r
2 K:Uml 1
6 a
A 4-'"
I E
b s
K g
/
h If K
h,Akt M
/'
n K,
4 A,
Figure 6.3 Spring Mass Simulation For A Two Dimensional Motion Revesen 1
.(-
i
), Fy Y J B
L.
j g
= Fx
=x
~
(a) TOP VIEW Zo I
F a
7 s
g
(
=F x (b) AXlAL CROSS S ECTION ( B-B )
in u n,,,,,,,
i
~
l Figure 6.4 (al Horizontal Cron Section of Rack (b) Vertical Cron Section of Rack
CELL Z(W)
U WALLS
[
C t
E/fEll
/ ld/llls'L
' :::,'y;,'s -
. /t ff
.=u,C, )
C C
AI.
y(V)
A RIGID PLATE 8
/
f /p
= x(u)
/
i s a),
D P7 j
/
P d."l::Mllll S UPPORTS l
Figure 6.5 hMZ M
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