ML20133E727
| ML20133E727 | |
| Person / Time | |
|---|---|
| Site: | 07109168 |
| Issue date: | 08/26/1985 |
| From: | CHEM-NUCLEAR SYSTEMS, INC. |
| To: | |
| Shared Package | |
| ML20133E722 | List: |
| References | |
| NUDOCS 8510090517 | |
| Download: ML20133E727 (43) | |
Text
,
b APPENDIX A DESCRIPTION AND SAFETY ANAI.YSIS FOR AN OPTIONAL RATCHET BINDER CLOSURE SYSTEM FOR THE CNS 8-120B SHIPPING PACKAGE NRC DOCKET 71-9168
[NON-PROPRIETARY VERSION]
Revision 0 Dated August 26, 1985 by CHEM - NUCLEAR SYSTEMS, INC.
135 Darling Drive Avon, CT.
06001 8510090517 850826 PDR ADOCK 07109168 C
?
s TABLE OF CONTENTS 1.0 General Information 1.1 Introduction 1.2 Package Description 1.3 Appendix 2.0 Structural Evaluation 2.1 Introduction 2.2 Hypothetical Accidents - 30 foot drops 2.2.1 Analysis Method 2.2.2 End Drop 2.2.3 Corner Drop 2.2.4 Side Drop 2.2.5 Evaluation of Ratchet Binder Assembly 2.2.5.1 Ratchet Binder Loads 2.2.5.2 Ratchet Binder Component Stresses 2.2.5.3 Shell Stress Evaluation 1
2.3 Supplemental Information 3.0 Thermal Evaluation 4.0 Containment 5.0 Shielding Evaluation 4
6.0 Criticality Evaluation 7.0 Operating Procedures 8.0 Acceptance Tests and Maintenance i
References J
9 s
LIST OF FIGURES A.1-1 CNS 8-1208 General Arrangement A.1 -2 Bolted Closure Details A.1-3 Ratchet Binder Closure Detail A.2-1 Stress - Strain Characteristics for Impact Limiter Foam A.2-2 Backed -vs-unbacked Regions A.2-3 Impact Limiter Deformations for the Corner Drop A.2-4 Load Path During Corner Drop A.2-5 Free Body Diagram for Corner Drop A.2-6 Ratchet Binder Loading A.2-7 Ratchet Binder Components i
f l
s APPENDIX A 8-120B CASK, OPTIONAL LID CLOSURE SYSTEM 1.0 GENERAL INFORMATION
1.1 INTRODUCTION
This Appendix provides a description and safety analysis of an optional primary lid closure system for the model CNS 8-1208 package. The present lid closure systen, consisting of 20 - 2 inch diamete'r bolts, is described and evaluated in the CNSI SAR Revision 2, dated March 1984.
(Reference 1) The optional lid closure system replaces the bolts with 12, ratchet binders. The ratchet binder design l
results in improved operational efficiency with a consequential reduction in personnel exposure consistent with the intent of the CNSI ALARA policy. The optional closure system also results in nodifications to the bolting ring and upper impact limi ter. Details of these changes are described in detail in this Appendix.
Analyses were performed in those areas affected by this option and results are presented as a comparison to acceptable results which were previously reported in the March 1984 SAR.
1.2 PACKAGE DESCRIPTION The features of the 8-120B package are as described in Section 1.2.1 of Reference 1, with the exception of the three itens summarized below.
BOLTED DESIGN RATCHET BINDER DESIGN 20 - 2" Dia. Bol ts 12 -
Ratchet Binders 21/2" thick bolt ring thick upper flange ring (SA-516 Gr 70) impact limiter as depicted impact limiter as depicted in CNSI DWG C-110-E-0007 in CNSI DWG 24504-1 (Reference 1)
(Section 1.3 of this Appendix)
Figure A.1-1 depicts the general arrangement of the 8-120B cask with the bolted design. The region affected by the optional closure systen is hi ghli gh ted.
Detailed figures which depict the differences between the bolted closure and ratchet binder closure are provided as Figures A.1-2 and A.1-3.
Al-1
9
~ ~ ~
' N N
See Figures i
g A.1-2 and
.s47 l
p A.1-3 for
-t lid closure details
,5~'
5
. '.s l.e. '.
I e.
A /
,x
- x x
t, PRIMARY LID g
f l l N K
i SECONDARY LID
. llhX V
1 g
i
'l
\\
. a!6 OVERPACK FOAM I
l
..I'.
?V i
~ ',, *
- 4 INhER SHELL h
. ~-
TIE-DOWN ARM OUTER SHELL FIRE 5HIELD Fi gure A.1-1 CNS 8-120B GENERAL ARRANGEMENT Al-2 l
l
,,f IMPACT LIMITER q l
/
i
\\
h, i
PRIMARY BOLT j
s 40' ll BOLTING RING j
p j
i NPRIMARY LID i$<$
\\
l8
/
W;r
/
/
I
/
/
~ <
f h, b CASK BODY e
c
/
r
~
14.4
=
e Figure A.1-2 BOLTED CLOSURE DETAILS Al-3
O IMPACT LIMITER 7'2N RATCHET BINDERS s
ASSEMBLY
,x x
^
~
RATCHET BINDER LID LUG n
w
/
p.
U i
=
I
'lll
\\
\\Y PRIMARY LID i
i i
,>-./
'P UPPER (9 /
/
t FLANGE RING X
/
v v
/
/
RATCHET BINDER
/
bwlNNER WALL BODY LUG
(
v CASK BODY OUTER WALL
\\ LEAD FIGURE A.1-3 RATCHET BINDER CLOSURE DETAIL i
A1-4 l
?
The ratchet binder design provides for twelve upper lugs which are welded to the primary lid and twelve lower lugs which are welded to the cask body. The details of the actual ratchet binder are shown on CNS Drawing 24504-1 sheet 1.
The upper flange ring is increased in thickness from 2-1/2" to and a stronger material is selected. The previous bolt ring was A516, gr 70 (Sy = 38,000 psi and Su = 70,000 psi). The material selected for the new flange ring is Note that this thicker and stronger flange ring (or bolt ring) is also acceptable for use in the bolted closure option.
That is, the flange ring can be used in both closure options, however the 2-1/2" ring can only be used on a cask which employs the bolted closure.
The upper impact limiter for the ratchet binder design has twelve cut out regions to provide clearance for the ratchet binders. This reduction in impact limiter volume is compensated for by extending the length of both impact limiters an additional inches along the cask side wall.
]
1.3 APPENDIX CNSI Drawing 24504-1 Rev 1, sheets 1, 2, aiid 3 CNSI 8-120B Shipping Cask with Ratchet Binders NOTE The drawings identified here contain information held as proprietary by Chem - Nuclear Systems, Inc. There-fore these drawings are not included in the non-proprietary version of this report.
A1.5
?
2.0 STRUCTURAL EVALUATION 2.1 INTRODUCTIO_N, This section provides a discussion of the design and analysis associated with the ratchet binder closure system for the 8-1208 package.
Analysis previously presented in reference 1 have demonstrated the adequacy of the 8-120B package design using a bolted closure. The structural consequences of the ratchet binder design have been evaluated, and areas which are affected have been re-analyzed using the same methodology as that previously used.
It has been determined that the only areas affected by this change are the hypothetical 30 foot drops. The new design is such that the stresses imposed on the cask are within the limits of the design criteria established in Reference 1.
2.2 HYPOTHETICAL ACCIDENTS - 30 FOOT DROPS 2.2.1 ANALYSIS METHOD Analyses have been performed to demonstrate the acceptability of the l
ratchet binder closure option. The analysis consists of an impact limiter evaluation to determine the loadings on the cask. These limiting loadings are then compared to those loadings that were previously found to be acceptable in Reference 1.
This analysis also determines the limiting crush depth of the limiter to verify the acceptability of the design.
The behavior of the impact limiter and its loading on the 8-120B cask is evaluated using the computer program CASKDROP. The basic technique used in this program is described with the following steps:
1.
Inpose an incremental deformation, or crush distance, on the impact l imi ter.
2.
Based on the deformed geometry, calculate the strains throughout the impact limiter.
3.
Based on the stress - strain curve for the foam and a one dimensional model for the foam, calculate the stresses in the impact l imi ter.
4 Calculate the total force in the impact limiter.
5.
Calculate the energy absorbed.
m
=
\\
.)
GX o
6.
Repeat the process until all the energy is absorbed.
A2-1
9 O
For each drop orientation the CASKDROP program is used in a conservative nanner to bound the behavior of the impact limiter and the loads it imposes on the cask. To bound the uncertainties of the stress - strain curve, effectively both the stiffer and the softer stress - strain curves are used, see Figure A.2-1.
In addition to bounding the stress - strain behavior of the foam, bounding assumptions are used for the possible stress distribution, or the effectiveness of the regions of the impact l imi ter.
To produce the upper bound of the loads on the cask, the stiffer stress -
strain curve is used and all backed and unbacked regions of the impact limiter are considered effective.
Figure A.2-2 illustrates the backed and unbacked regions of the impact limiter considered for each of the three drop orientations. To produce the upper bound on the maximum deformations of the limiter, the softer stress - strain curve is used and only the backed regions, or regions that project vertically up to the cask body, are considered.
The actual G load imposed on the cask and ccush deformations are expected to be between the values predicted by these bounding analyses. A CNSI drop test (Ref. 2) on the CNSI 1 - 13 C II, which is a cask with a similar impact limiter geometry, demonstrated that the unbacked regions are partially effective in absorbing energy. The analytical method used in this evaluation does not model the effect of minor geometry changes or include the effect of the stainless steel canning. However, this method does conservatively predict the bounding behavior of the impact limiter.
At twelve locations around the sides of the cask, small regions of the impact limiter's foam have been removed to accomodate the addition of the ratchet binders and lugs.
However, this region is not completely void and is occupied by the ratchet binder. The CASKDROP code does not explicitly model this localized geometry. The effects of this detail are discussed in the following sections.
2.2.2 END DROP The ratchet binder detail will have no effect on the bounding predictions of the CASKDROP code. The results are as follows:
Case G's Crush Distance Unbacked case, Soft Foam 62 7.4 in i
Backed case, Hard Foam 168 3.13 in The amount of foam removed from the lid region to accomodate the ratchet binder lid lug is negligible compared to the total volume available.
Therefore, the results for the unbacked case will not change with the new geometry. The bounding fully backed case with the harder foam is still the upper bound for the maximum load applied to the cask, and thus, the previous analysis of the cask for the end drop is still valid.
A2-2
?
2.2.3 CORNER DROP The length of each impact limiter along the side of the cask is increased l
inches. The bounding analysis with the CASKDROP code for the new geometry results in the following results:
G load Crush i
-Case Distance Unbacked, Soft Foam 51.8 17.3 60.8 15.4 Backed, Hard Foam The bounding deformations are shown in Figure A.2-3.
The actual deformation is between these values. This deformation is not close to the ratchet binder, and' therefore, the ratchet binder will not significantly alter the results. The limiting G load predicted for this case is less than 1% greater than that previously determined for the bolted closure design. Therefore, the previous stress evaluation of the cask body for the corner drop remains valid everywhere except in the immediate vicinity of the ratchet binder attachment points. A stress evaluation for the ratchet binders and the cask shell in the vicinity of the ratchet binder attachment points for the corner drop is provided in Section 2.2.5.
2.2.4 SIDE DROP The addition of ratchet binders has the greatest effect on the side drop analysis. The CASKDROP code for the previous design predicted the following bounding results:
Case G's Crush Distance Unbacked Soft Foam 92 9.4 in Backed, Hard Foam 108 5.7 in The maximum crush distance based only on the backed regions and the softer foam may be at the edge of the ratchet binder. Even though this is a conservative estimate of the crush distance, the length of each impact limiter along the side of the cask has been increased inches to l
decrease the bounding maximum deformation of the impact limiter. The CASKDF.0P results for the new geometry are as follows:
Case G's Crush Distance Unbacked, Soft Foam 90.7
.8.8 in Backed, Hard Foam 112.7 5.6 in A2-3
?
The maximum deformation is between tha 8.8 and 5.6 inch values. This crush distance, assuming the drop position of the cask is such that a ratchet binder location corresponding to the direct point of drop contact, is at least inches from the edge of the ratchet binder and may be as far as inches from the edge of the ratchet binder.
If it is assumed that during the crushing of the foam, the foam in the vicinity of the ratchet binder moves into the region of the void, then
.the volume or the effective thickness of the impact limiter is reduced.
This assumption can be simulated with the CASKDROP code by using an equivalent outside diameter of the impact limiter, corresponding to the total volume of the impact limiter, excluding the void volume.
The volume of the foam removed is:
LHW V
=
length along the. side of the cask, inches L
=
- height, inches H
=
wi dth,
inches W
=
598, cubic inches.
V (each Void)
=
=
7182 cu inches.
12 x 598 Y (total)
=
=
This volume is the total void space and it conservatively neglects the volume of steel added by the ratchet binders. The volume of each impact limiter, neglecting the portion that projects beyond the end of the cask is:
w 2
V=
T (Do2 - Di ) L Do = 102 Di = 73.2 L = 21.
V = 83,221 cubic inches.
The volume of the equivalent impact limiter is 76,039 cubic inches.
The equivalent diameter, Deq, of this impact limiter is:
Deq =
(4)(76,039) + (73.2)
= 99.8 in
'tr' 2l This outer diameter is assumed on both the upper and lower impact limiters, and the behavior is predicted with the CASKDROP code. The results for an unbacked, soft foam case (used to predict the bounding deformation) are 99.4 G's and 8.6 inches of crush displacement.
Since the G loads have not charined significantly and the maximum displacement is only 8.6 inches, the impact limiter does not bottom out.
Since the length of the impact limiter along the side of the cask has been increased, the bounding G - load applied to the cask increases slightly. The new load (Backed case, hard foam) is 112 G's compared to the 108 G's of the previous evaluation. The stresses in the cask due to the higher load can be obtained by a ratio method. The limiting factor of safety for the side drop in the bolted closure design was 1.08 (Reference 1, page 2-127). The revised limiting factor of safety is 1.00 (108/112) or 1.04 Therefore the results of the side drop analysis are acceptable.
A2-4
9 i,
i i
t i
I l
I I
~i4 i
i I l ff l
I lll O
rI O
9 I
/'
x 10 l
l I
i}l 6
D l
Q.
l i
l
/ /.
v 6
(.D l
l l
.///
1a' l
U) l I
iR l
w 3
l
\\
}f' n
,//
/
(f) s 4
l
/X'
- w
-_- =. &.W g
g..----
[
0 10 20 "S O 40 50 60 70 so 90 100 STRAIN
(%)
FIGURE A.2-1 COMPRESSIVE STRESS - STRAIN CHARACTERISTICS FOR 25 lb/ft3 IMPACT LIMITER FOAM MATERI AL I
A2-5
4 KEY B = BACKED REGION EIJD DROP u = UNBACKED REGIOIJ i
a ul8 8 i u CORilER DROP i
'u i
i uj B
r SIDE DROP lg u
FIGURE A.2-2 BACKED -VS-UNBACKED IMPACT LIMITER REGIONS FOR CASK DROP ORIENTATIONS A?-6
b
/
- ,. ?
l.;
I i
\\
- MAXIMUM DEFORMATION j
(UNBACKED, SOFT FOAM)
~
i d
-MINIMUM DEFORMATION (BACKED, HARD FOAM )
30.28 j
o 4
y FIGURE A.2-3 BOUNDING IMPACT LIMITER DEFORMATIONS FOR THE CORHER DROP A2-7
1 2.2.5 EVALUATION OF RATCHET BINDER ASSEMBLY 2.2.5.1 RATCHET BINDER LOADS The ratchet binders experience the largest load during the 30 foot drop of the cask onto a flat unyielding surface. The design of the ratchet binder assembly is such that the ratchet binders carry only the axial tensile loads. The compressive loads and the shear loads arising due to the drop conditions are transferred directly between the primary lid and the cask body.
Therefore, tne largest loads in the ratchet binders occur due to the corner drop condition. These loads are evaluated 17 a conservative manner as indicated in the following paragraphs.
The inertial loads arising due to the 30-feet corner drop condition are in equilibrium with the impact limiter reaction at every instant of time during the drop. Figure A.2-4 shows the path the loading follows internally to achieve the equilibriun.
To evaluate the loads in the ratchet binders, the ratchet binders and the lid are isolated from the rest of the cask and a free-body diagram is constructed as shown in Figure A.2-5.
The in-plane loads shown in the figure do not contribute towards the loading in the ratchet binders. The out-of-plane inertia loads tend to open the lid about point 0 whereas the ratchet binder loads and the impact limiter reaction tend to close it down.
The largest loads in the ratchet binders are obtained by assuming that the ratchet binders by themselves resist the entire opening moment.
Assume that the lid combination (primary and secondary lids) is perfectly rigid (reasonable because of the 61/2" thickness of each lid) then the lid will have the tendency to pry open about point 0 and the load distribution in the ratchet binders will be linear in the projected diametric plane. This distribution is shown on Figure A.2-6 and can be mathematically represented as:
= 1/2 F max (1-cos O)
EQH 1 FR (0)
R Axial load in a ratchet binder located at an where, FR (e)
=
angle 0 from the point of impact.
R Axial load in the ratchet binder farthest F max
=
from the point of impact i.e., at an angle of 1800 from the point of impact.
1 e=
Angle measured from the point of impact 1
A2-8 l
l
Q IMPACT LIMITER INERTIA f
I o
CASK INERTIA PAYLOAD INERTIA' y
s
/
RATCHET s
BINDER LOAD IMPACT LIMITER REACTIONS IMPACT LIMITER REACTION i
ICOMPRESSIVE LOAD BETWEEt CASK BODY AND PRIMARY LID j
FIGURE A2-4 8-120B CASK LOAD TRANSFER BETWEEN VARIOUS COMPONENTS OF THE CASK A2-9
t
.RADI AL LOAD FROM THE CASK BODY RATCHET BINDER f
LOAD IMP ACT LIMITER I
I REACTION C ASK INERTIA (UPPER PORTION)
I IMPACT LIMITER REACTIO l
ADI AL LO AD (LOWER PORTION) l FROM THE C ASK, BODY I
l FIGURE A2-5 FREE - BODY DIAGRAM OF CASK 8-120B FOR CORNER DROP A2-10
Fe, (e) = '/ IR mu (I' ' * *)
2 PRIMARY LID FR mw
/
x s
s N
R x
s If N
FIGURE A2-6 VARI ATION OF RATCHET BINDER LOAD ALONG THE CIRCUMFERENCE l
OF THE LID A2-11
The resisting moment can be evaluated by taking a moment of the ratchet binder loads about point 0.
N FR (Bj) x R (1-cos0j)
=
N MR 1/2 F max xRr[(1-cosOj)2 EQN 2
=
R i=1 where, Mg= Resisting moment about point 0
R = radius of ratchet binder location 6
=1ocation of i-th ratchet binder i
No. of ratchet binders N
=
For 12 ratchet binders, eqn. (2) becomes MR
- 9 F max xR EQN 3 R
)
The opening moment due to the pay-load and lid inertia can be calculated as follows:
i p + M ) x a x R cosQ EQN 4 (M
M 1
=
o Opening moment about point 0 where, No
=
14,680 lbs Payload mass M
=
=
p 7,080 lbs lid mass i
M1
=
=
maximum deceleratior. during the corner drop a
=
60.8 g's
=
O( = angle of inclination of the cask during corner drop 30.2817 degrees
=
38.85 inch Ratchet binder circle radius R
=
=
Equating eqns. (3) and (4) and rearranging we get p + M ) x a x cos O(
EQN 5 Fmax " I/9 (M L
127,000 lbs 126,944 lbs
=
A2-12
O 2.2.5.2 Ratchet Binder Stress The ratchet binders of the 8-120B cask are designed to provide the closure of the cask without failure during the normal and hypothetical accident conditions. The largest load in the ratchet binders occur during the hypothetical corner drop accident conditi on. This load is estimated to be 127,000 lbs (see Section
- 2. 2. 5.1 ).
An evaluation of the ratchet binder assembly is performed to ensure that the stresses in the entire assembly renains within the allowable values.
A summary of the minimum factor of safety for each component of the ratchet binder assembly under the design load is presented in Table A.2-1.
The details of the evaluation are presented in the following paragraphs.
Figure A.2-7 shows the detail of a ratchet binder assembly used in the 8-120B cask. The assembly is comprised of the following components:
(1 ) Ratchet Binder Bolt (2) Ratchet Binder Lugs (3) Ratchet Binder Pins (4) Ratchet Binder Lid Lug (5) Ratchet Binder Body Lug The material properties and the allowable stress values for each component is given in Table A.2-2.
(1) Ratchet Binder Bolt The ratchet binder bolt is fabricated from a dia shaft (Item No. 74 on detail drawing). The threaded portion of the bolt has a nominal diameter with thread specification of 8 UN. Under the axial loading, the two modes of failure of the bolt are identified as the shear-cut of the thread and axial tension of the root. The largest stresses in the bolt under these modes are calculated in the following paragraphs:
Shear-Out of Threads inch Minor diameter
=
inch Thread engagement length
=
8.922 in2 Shear Area =Tx
=
14,234 psi Average Shear Stress = 127,000/8.922
=
28,468 psi 2 x 14,234 Stress Intensity
=
=
105,000 psi Allowable Stress Intensity
=
3.69 > 1.0 105,000/28,468 Factor of Safety
=
=
A2-13
TABLE A.2-1 1
MINIMUM FACTOR OF SAFETY DURING HYPOTHETICAL ACCIDENT CONDITION FOR RATCHET BINDER ASSEMBLY COMPONENT COMPONENT STRESS INTENSITY ALLOW ABLE S. I.
MINIMUM FACTOR (psi)
(psi) 0F SAFETY 1.71 Ratchet Binder Bolts 1.18 Ratchet Binder Lugs 1.41 Ratchet Binder Pins 1.21 Lid Lugs 2.00 Body Lugs
4 TABLE A2-2 MATERIAL PROPERTIES & ACCIDENT CONDITION ALLOWANCE S.I.
FOR RATCHET BINDER ASSEMBLY COMPONENTS Component Material Sy Su Accident Condition Allowable S. I.
Speci fication (Ksi)
(Kst)
Mean III Mean & Bending (2)
(Ksi)
(Ksi)
Ratchet Binder Bolts D
Ratchet Binder Lugs Ratchet Binder Pins Lid Lugs Body Lugs Smaller of (2.4 Sm and 0.7 Su)
Notes:
(1 ) Mean Allowable
=
Smaller of (3.6 Sm and 1.0 Sul (2) Mean & Bending Allowable
=
s
4 4
'/
/_ _ _
@ RATCHET BINDER PINSs\\\\3 en4Tcstrsinotasotr g'
P an y
\\
/
m Qh /
@ aarcm einota tuos //
g
/
/
@aircscrsinosassetttuo 2- _
FIGURE A.2-7 RATCHET BINDER COMPONENTS A2-16
D Axial Tension of the Root in2 Stress Area
=
psi Tensile Stress
=
g psi Stress Intensity
=
Allowable Stress Intensity
=
1.72 > 1.0 Factor of Safety
=
=
(2) Ratchet Binder Lugs The ratchet binder assembly is comprised of four lugs, two on each side, which are used to connect the assembly with the cask via diameter tight fitting pins. These lugs are made of material and have the dimensions as indicated on the sketch.
Under the design loading, the three modes of failure of the lugs are indentified as (1) local compression due to pin contact, (2) Primary tension of the net area and (3) tear-out shear.
Each of these failure modes are addressed in the following sections.
y n
4 Il ll li
/g
_1!.
L.
/
d-(+)
m A
v>d="
Q
, M...
J i
-.-~
(0 -c @
2 2
)
Y\\ \\
2.___.
2 O
D A2-17
o LOCAL COMPRESSION DUE TO PIN CONTACT The contact pressure around the circumference of the hole can be expressed as:
gnax Sin 0 which gives a uniform pressure in the q (B)
=
diametric plane of the hole. The horizontal component of this pressure distribution is balanced with one another and the sum of the vertical component equals the applied load for a rigid pin fitting with small clearance. The maximum compressive stress can be obtained as Oc~ = 2W/( v rt) h" 63,500 lbs 127,000/2 W
=
=
inch r =
inch l'
t
=
j i p, I -
U=
g' e
i c
psi
- o,l
=
,g
.'o Psi Pm
=
[
2r i
Factor of safety
=
2.05 > 1.0 a,
=
un
- .. m '__L PRIMARY TENSION OF THE NET AREA The average tensile stress over the net area can be calculated by dividing the ratchet binder load by the net area that carries this load.
CTt W/ (D-d) x t
=
63,500/
=
psi
=
Psi <
Psi Pm
=
3.18 > 1.0 Factor of safety
=
=
A2-18
For a rigid pin fitting with small clearanca, Ranrence 3 gives the following formula to evaluate the maximum tensile stress in the ratchet binder lugs.
7 x 7.04 (A-1)/K CT t
max where 7t nominal tensile stress
=
1=
D/d ratio
=
~
there fore, Ci ax m
psi
=
This stress is peak in nature. However, it will be conservatively classified as membrane plus bending and will be compared with the corresponding allowable:
Pm+Pb
' Psi <
psi
=
1.18 > 1.0 Factor of safety
=
=
TEAR-0VT SHEAR Due to the load applied by the pin on the lug, tear-out of the lug may be caused due to the excessive shear stress as shown in the sketch. The average shear stress can be calculated by using the following formula:
T= W/ 2 x (R-r) x t 4
63,500/
=
psi
=
27 =
psi < ~
psi P
=
m 1.59 > 1.0 Factor of safety
=
=
(3) RATCHET BINDER PINS The ratchet binders are connected to a lug on the cask body on one i
end and the lug on the lid by two tight fitting pins of nominal diameter and made of
' steel. Due to the nature l
of the applied load, these pins are subjected to both shear and bending stresses. The following calculations show the adequacy of these pins under the accident condition loading.
A2-19
O W
h MAXIMUM SHEAR STRESS 127,000/2 W/2 Shear Force
=
=
63,500 lbs u
=
in2 Shear Area = '7f x
=
63,500/;
Average Shear Stress
=
(=
psi Average membrane S.I., Pm
- 2 X N
- psi <
Psi 1.41 > 1.0 Factor of safety
=
=
MAXIMUM BENDING STRESS Conservatively assume the pin to be a simply supported beam of l ength inch with uniform loading. The largest bending moment occurs at the mid-span and its magnitude is:
in-lb 127,000 x
/8 Wx
/8 Mmax
=
=
=
in3 Section Modulus 2 = 7( x
-3/32
=
Maximum Bending Stress
=
6 Psi b
Conservatively assume that the maximum bending and maximum shear stresses occur at the same location. Then, the linearized mean plus bending stress intensity can be obtained from the following formula:
2xg62/4 + g2 '
Pm + Pb
=
b 24+
2' 2xy
/
=
psi e psi
=
1.53 > 1.0 Factor of safety
=
=
A2-20
1 1
(4) RATCHET BINDER LID LUG The ratchet binder lid lugs are fabricated from
" thick f
steel plates. They are welded to the lid by
" groove welds around two sides of the lug and a
" fillet around the other side of the lug. The ratchet binder loading gives rise to both shear and bending stresses in the lug. The lugs are designed to withstand these stresses. An evaluation of the welds is also performed to determine their adequacy under the design ratchet binder load.
"p
[f t
CJ o
l oW LUG SHEAR-00T in2 Minimum shear area
=
=
127,000 psi Ratchet Binder Design load W
=
Average Shear Stress, T= 127,000/
psi
=
psi <
psi Mean Stress Intensity
=
=
1.48 > 1.0 Factor of safety
=
=
A2-21 l
LUG BENDING in-lb 127,000 x Maximum Bending Moment
=
=
in3 Section Modulus
=
=
Maximum Bending Stress, CTb psi
=
Conservatively assume that the largest bending and shear stresses occur at the same location. Then, the linearized mean plus bending stress intensity can be obtained from the following formula.
+ 72 2 x CTb Pm + Pb
=
2'
= 2 xg 2/4 +
psi e psi
=
- 1. 21 > 1. 0 Factor of safety
=
=
WELD EVALUATION The groove welds form a rectangular area of
-" over the lid surface. The compressive load and bending moment due to the ratchet binder load is transferred to the lid through this area.
JP g
a w
A GROOVE WELD
.ll1tlltllll 1//// /////////ii
/
/
t q t t s t \\ ) '. ) s,
. i l i \\ \\ \\ s ' 'i. ' \\ \\ \\ t \\ t til
&^
/
l
/
.s
=
=
SECTIOWA C A2-22 i
I
W = 127,000 lbs Compressive load, P
=
127,000 x Bending Monent, M
=
in-lb
=
127,000/
Mean compressive stress,(Tc
=
psi
=
Bending stress, CTb psi
=
Membrane plus bending S.I.
=
psi <
psi
=
=
- 1. 33 p-1.0 Factor of safety
=
(5) RATCHET BINDER BODY LUG The ratchet binder body lugs are fabricated from
" thick steel plates. They are welded to the cask body by
" groove wel ds on the two longitudinal sides and fillet on the remaining two sides. The ratchet binder loading is primarily a shear loading on the body lug. A smaller bending load occurs due to eccentric loading. The lugs are designed to withstand these loads.
W me W
u s'
I
/$2t_
Dh.
s
\\
(
\\
\\
s I
t
_J A2-23
LUG SHEAR-00T in2 Mimimum shear area
=
=
127,000 lbs Ratchet Binder Design Load, W
=
Average Shear Stress, T= 127,000/
psi 2x7=
psi c psi Mean Stress Intensity, Pm
=
2.00 > 1.0 I
Factor of safety
=
=
LUG BENDING in 1b 127,000 x Maximum Bending Moment, M
=
=
=
=
in3 Section Modulus, 2 Bending Stress,7 = M/Z psi
=
=
b Conservatively assume that the largest bending and shear stresses occur at the same location. Then, the linearized mean plus bending stress intensity can be evaluated from the following formula.
Pm +Pb 2xg[/4 +72
=
~
2' xg 2/4 +
2
=
psi <
psi
=
= 2.79 > 1.0 Factor of safety
=
WELD EVALUATION The maximum stresses in the groove weld of the cask body lug are bounded by the stresses in the lug itself. Therefore, the J
calculations performed above limit the maximum stresses in the wel d.
The stress intensities are summarized here.
Psi <
psi Mean SI., P m
2.00 > 1.0 Factor of safety
=
=
Mean + Bending S.I., Pm+Pb Psic psi
= 2.79 > 1.0 Factor of safety
=
A2-24
2.2.5.3 SHELL STRESS EVALUATION The ratchet binder loads during the hypothetical accident condition are transferred to the cask body through the cask boc(y l u gs. Because of the small size of the lugs, stresses are concentrated near them.
A conservative approach used by the piping industry (Reference 4) has been employed to evaluate the stresses in the cask body due to the ratchet binder load transfer. These stresses are added to the stresses in the cask body due to cask and payload inertias computed in Section 2.2.5.1.
Conservatively the largest stress intensities in the cask body are added to the stress intensity due to ratchet binder load to analyze the cask shell.
t I
~2L ML o
a p
f,r o
2L, L
/
ug Q
g" 2
127,000 lbs W
Longitudinal load Q2
=
=
=
285,750 in. Ib ML Longitudinal Moment
=
=
35.85 inch Mean cask radius
=
r =
1.5 inch thickness of the cask wall
=
t =
7 = r/t 23.90
=
inch L1 Half Lug width
=
=
inch L2 Half Lug Length
=
=
inch Lb Lesser of L1 and t
=
=
L /r B)
=
=
1 B2 L /r
=
=
2 X1
= -0.45 + l og B)
=
Yj
= -0.55 + log B2 A2-25
i 7]=-(X1 cos 50* + Y1 sin 50*) - 1/2 (X1 sin 50* - Y1 cos 50*)2
=
0.51 x (7) 1 74 B1 Bj(7/)4 74 CL
=
2/3 x CL BL
=
=
2L1J/3 L
211
=
=
ML BL +1 L+P) LUG (P
=
b Z11 2L L2b
=
+
psi
=
Stress intensity in the shell due to cask and payload inertia is 22,431 psi (Reference 1 page 2-148.11). Therefore, the total S.I. in the cask body with the ratchet binder arrangement will be psi c:
psi Pm + Pm
=
+
=
1.2677== 1.0 Factor of safety
=
=
2.3 SUPPLEMENTAL INFORftATION The following pages are provided to summerize the computer input and output data (CASKDROP program) for the analysis of the impact limiter used on the 8-120B cask with the ratchet binder lid closure, 3.0 THERMAL EVALUATION The ratchet binder option does not affect the results of the thermal analysis previously provided in Reference 1.
A2-26
e 08-00-1985 15:03:13 CASK GEOMETRY Corner Drop Analysis G= 306.4 in/sec^2:0>
Caul:: UO12nli G-12OH CASK
>>>>>> Pact. age uses correction factor t abl e: stanrf ard Weight (lb) W 74409 Outer diamter (in) POD Length (in) LC Drop height (f t) H 30 CG (cast: btm)
(in) LCG 65.34 Moment of Inertia ICG O
(LP SEC^2 INCHES)
]
Ovp materials: Top: FR6725H Dottom: fr6725s Upper Lower (All values in inches) l Inner diameter (in) OID Outer diameter (in) DOD Inner thici. ness (in) LI Outer thici: ness (in) LO Press space bar to proceedOH-OH-1985 15:03:15 CASK DROP RESULTS y
Corner Drop Analysis METHOD 1
Cast:80120B 8-120B CASK Overpact::fr6725s
==
ALPHA:
30.28196 Iteration Time Deflection Acc Force E(abs)
BOTTOM DOWN 66 0.0490 17.3294
-51.8 3926115.
28092996.
Correction factors 1 : O 2: O 3: 1 4 : 1 5: O 6: 1 7 : O 8: O 9: 1 10 : 1 11 : 0 12 : 1 13 : 0 14 : 1 15 : 0 eaannnn
e 08-08-1985 14:56:07 CASK GEDMETRY Corner Drop Analysin Cast :8012014 0 -12OH CASK G= 306.4 in/sec^2>>;
> > > > >> Pacl: age uses correction f at: tor t abl e: s t antiard Weight (Ib) W 74400 Outer diamter (in) POD Length (in) LC Drop height (ft) H 30 CG (cast: btm)
(in) LCG 65.34 Moment of Inertia ICG n
(LB SEC^2 INCHES)
Ovp materials: Top: FR6725H Bottom: fr6725h Upper Lower (All values in inches)
Inner diameter (in) OID Outer diameter (in) OOD Inner thiciness (in) L1 Outer t hi cl: ness (in) LO Press space bar to proceedOH-08-1985 14:56:09 y
'?
CASK DROP RCSUL i S Corner Drop Analysis ME'sHDD 4
Cast:80120D 8-120B CASK O /erpact:: f r6725h
==
ALPHA:
30.20196 Iteration Time Deflection Acc Force E(abs)
BOTTOM DOWN 59 0.0440 15.4031
-60.0 4597580.
27956234.
Correction factor 5 1 : 1 2: 1 3: 1 4 : 1 5: 0 6 : 1 7 : 1 8 : 1 9 : 1 10 : 1 11 : 1 12 : 1 13 : 1 14 : 1 15 : O
t 9
O 08-05-1985 11:50:16 CASK GEDMETRY Side Drop Analysis Cast:80120B O-120D CASK G= 386.4 i ri / s ec ^2 > > >
>>>>>> Package uses correction factor table: standard Weight (1b) W 74400 Outer diamter (in) POD Length (in) LC D.~op height (ft) H 30 CG (cask btm)
(in) LCG 44 Moment of Inertia ICG O
(LB SEC^2 INCHES)
Ovp materials: Top: FR6725S Dottom: FR6725S Upper Lower (All values in inches)
Inner diameter (in) OID Outer diameter (in) DOD Inner thici. ness (in) LI Outer thickness (in) LD M
08-05-1985 11:50:17 k
CASK DROP RESULTS Side Drop Analysis METHOD 1
Cash:80120B O-120B CASE Overpacks:FR6725S
!< FR6725S
- DATA EXTRAPOLATED AFTER 80
- 7. !<
UO 7.****
Iteration Time Deflection Acc Force E(abs)
Top 62 0.0261 8.0404
-90.7 3409032.
13727437.
Bottom 8.8382
-90.6 3409244.
13720779.
Combined
-90.7 6019076.
27448216.
Correction factors 1 : O 2: O 3: 1 4 : 1 5: 0 6: 1 7 : O 8 : O 9: 1 10 : 1 11 : 0 12 : 1 13 : 0 14 : 1 15 : 0
t O
08-05-1985 15:26:55 CASK GEOMETRY Side Drop Analysis G= 306.4 i n / ser ^2 '> > >
Cask:80120B O-100D CASK
>>>>>> Package uses correction factor table: standard WeiOht (1b) W 74400 Outer diamter (in) POD Length (in) LC Drop height (f t) H 30 CG (cask htm)
(in) LCG 44 Moment of Inertia ICG O
(LB SEC^2 INCHES)
Ovp materials: Top: FR6725H Dottom: FR6725H Upper Lower (All values in inthes)
Inner diameter (in) DID Outer diameter (in) DOD Inner thickness (in) LI D
Outer thickness (in) LO Ea 08-05-1985 15:26:56 CASK DROP RESULTS Side Drop Analysis METHOD 2
Cask:80120B R-120B CASK Overpacks:FR6725H
& FR6725H
- DATA EXTRAPOLATED AFTER 65
%5 65 %****
Iteration Time Deflection Acc Force E(abs)
Top 40 0.0175 5.6741
-112.7 4230830.
13619237.
Bottom 5.6679
-112.6 4227416.
13593085.
-112.7 0458246.
27212322.
Combined Correction factors 1 : 1 2: 1 3: 1 4 : 1 5: 1 6: 1 7 : 1 0: 1 9 : 1 10 : 1 11 : 1 12 : 1 13 : 1 14 : 1 15 : 1 4
9 o
9
~
00-08-1985 14:16:53 CASK GEOMETRY Side Drop Analysis Casl::80120D 8-120D CASK d= 386.4 in/sec^2>>>
>>>>>> Package uses correction factor table: standard Weight (1b) W 74400 Outer diamter (in) POD Length (in) LC Drop height (ft) H 30 CG (cast btm)
(in) LCG 44 Moment of Inertia ICG O
(LB SEC^2 INCHES)
Ovp materials: Top: FR6725S Dottom: FR67255 Upper Lower (All values in inches)
Inner diameter (in) OID Outer diameter (in) ODD Inner thictness (in) LI Y
Outer thici: ness (in) LO S
08-08-1985 14:16:54 CASK DROP RESULTS Side Drop Analysis METHOD 1
Cast:80120B 8-120B CASK Overpacls:FR6725S 5 PR6725S
- DATA EXTRAPOLATED AFTER 00 00 %****
Iteration Time Deflection Acc Force E(abs)
Top 65 0.0252 8.6311
-99.4 3733425.
1371090R.
Bottom 8.6330
-99.4 3734208.
13716354 Combined
-99.4 7467633.
27427262.
Correction factors 1 : O 2: O 3: 1 4 : 1 5: O 6 : 1 7: 0 8: O 9: 1 10 : 1 11 : 0 12 : 1 13 : 0 14 : 1 15 : 0
b 4.0 CONTAINMENT The containment vessel, fabrication welds, and penetrations are the same in the ratchet binder design and the bolted lid design. (Reference 1 Section 4.0) The only difference between the two closure options is the mechanical means by which the primary lid is secured to the cask body.
Lugs welded at twelve locations each on the prinary lid and cask body provide attachment points for the 12 -
" ratchet binders. These ratchet binders are torqued to 120 + 10 foot-pounds to provide adequate preload on the silicone o-rings. The leak tightness of the closurg is demonstrated after fabrication by test to be less than or equal to 2.7 x 10-0 atm-cm3/see based on dry air at 25*C for a pressure differential of one atmosphere. The acceptability of this leak rate for nomal conditions of transport and for hypothetical accident conditions was previously demonstrated in Reference 1.
The test procedure to be followed for performing this leak test is also described in Reference 1.
5.0 SHIELDING EVALUATION The ratchet binder option does not effect the results of the shielding analysis previously provided in Reference 1.
6.0 CRITICALITY EVALUATION
No2 applicable for the CNS 8-120B package.
e A4-1
4.0 CONTAINMENT The containment vessel, fabrication welds, and penetrations are the same in the ratchet binder design and the bolted lid design. (Reference 1 Section 4.0) The only difference between the two closure options is the mechanical means by which the primary lid is secured to the cask body.
Lugs welded at twelve locations each on the primary lid and cask body provide attachment points for the 12 -
" ratchet binders. These ratenet binders are torqued to 120 + 10 foot-pounds to provide adequate preload on the silicone is demonstrated after fabrication by test to o-rings. The leak tightness of the closurg/sec based on dry air at 25'C for a be less than or equal to 2.7 x 10-0 a tm-cm3 pressure dif ferential of one atmosphere. The acceptability of this leak rate for nomal conditions of transport and for hypothetical accident conditions was previously demonstrated in Reference 1.
The test procedure to be followed for performing this leak test is also described in Reference 1.
5.0 SHIELDING EVALUATION The ratchet binder option does not effect the results of the shielding analysis previously provided in Reference 1.
6.0 CRITICALITY EVALVATION Not applicable for the CNS 8-120B package.
I 9
A4-1 l
w
e i
v 7.0 OPERATING PROCEDURES The cask loading and unloading procedures are essentially unchanged from those presented in Reference 1 for the bolted closure. The following revised steps are presented to accomodate a cask with either closure design. The indicated step numbers are based on the numbering scheme in Reference 1.
R; vised stip 7.1.4: Loosen and remove the thirty-two (32) bolts which secure the primary lid to the cask body, or loosen and release the 12 -
' ratchet binders which serve the same purpose.
Revised step 7.1.9 Replace and secure lid to cask body using the thirty-two (32) lid bolts lubricated and torqued using a star pattern to 500 + 50 ft.
lbs.
If the cask is equipped with lid ratchet binders, secure all twelve binder assemblies to the lid lugs using the supplied pin and cotter pin. Using a star pattern, tighten each ratchet binder to 120 + 10 ft.1bs.
Revised step 7.2.7: Loosen and remove the thirty-two (32) bolts which secure the primary lid to the cask body, or loosen and release the 12 -
" ratchet binders which serve the same purpose.
A7-1 l
9 i
f4 7.0 OPERATING PROCEDURES The cask loading and unloading procedures are essentially unchanged from those presented in Reference 1 for the bolted closure. The following revised steps are presented to accomodate a cask with either closure design. The indicated step numbers are based on the numberir.g scheme in Reference 1.
Revised step 7.1.4: Loosen and remove the thirty-two (32) bolts which secure the primary lid to the cask body, or loosen and release the 12 -
" ratchet binders which serve the same purpose.
Revised step 7.1.9 Replace and secure lid to cask body using the thirty-two (32) lid bolts lubricated and torqued using a star pattern to 500 + 50 ft.
lbs.
If the cask is equipped with lid ratchet binders, secure all twelve binder assemblies to the lid lugs using the supplied pin and cotter pin.
Using a star pattern, tighten each ratchet binder to 120 + 10 ft.1bs.
Revised step 7.2.7: Loosen and remove the thirty-two (32) bolts which secure the primary lid to the cask body, or loosen and release the 12 -
" ra tche t binders which serve the same purpose.
1 A7-1
6 c
8.0 ACCEPTANCE TESTS AND MAINTENANCE i
l l
8.1 ACCEPTANCE TEST l
The acceptance tests to be conducted prior to the first use of each CNS 8-120B package is as described in Reference 1.
The leak test procedure and acceptance criteria defined for the bolted closure will also be applicable to verify satisfactory performance of the ratchet binder closures.
8.2 MAINTENANCE PROGRNi The 8-120B package will be subjected to routine and periodic inspections and maintenance as previously described by Reference 1.
Ratchet binder asserblies and lugs will be visually inspected for wear and defects in the same manner that j
primary lid bolts are inspected in the bolted closure design.
Replacement components will be obtained in accordance with CNSI drawing 24504-1 for any ratchet binder component that shows cracking or other visual signs of distress.
l l
l A8-1 l
L
O s
REFERENCES 1.
Sa fety Analysis Report for Chem - Nuclear Systems, Inc. Model CNS 8-120B Type B Re &#aste Shipping Cask, Revision 2, March 1984.
2.
fafety Analysis Report for Chem - Nuclear Systems, Inc. Model CNS 1-13C II, Aevision 3 April 1982.
3.
Alexa'nder Blake, ' Practical Stress Analysis in Engineering Design',1982, Marcel Dekker, Inc., New York.
4 Welding Research Council Bulletin No.198, September 1974 I
t l
j i
i t
i l
i l
L