Response to Request for Information Items 3, 5, and 6: 

Physical Tests Performed on Spent Fuel Packages 

Enclosure 
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Table of Contents 

1. Model No. NAC-LWT (Docket No. 71-9225) .......................................................................... 1

2. Model No. GA-4 (Docket No. 71-9226) .................................................................................. 4

3. Model No. 2000 (Docket No. 71-9228) ................................................................................ 11

4. Model No. NAC-STC (Docket No. 71-9235) ........................................................................ 12

5. Model No. TN-FSV (Docket No. 71-9253) ........................................................................... 24

6. Model No. NUHOMS® MP187 Multi-Purpose Cask (Docket No. 71-9255) .......................... 27

7. Model No. HI-STAR 100 System (Docket No. 71-9261) ...................................................... 32

8. Model No. UMS Universal Transport Cask Package (Docket No. 71-9270) ....................... 35

9. Model No. FuelSolutionsTM TS125 Transportation Package (Docket No. 71-9276) ............ 36

10. Model No. TN-68 Transport Package (Docket No. 71-9293) ............................................... 42

11. Model No. NUHOMS®-MP197, NUHOMS®-MP197HB (Docket No. 71-9302) .................... 43

12. Model No. TN-40 (Docket No. 71-9313) .............................................................................. 47

13. Model No. HI-STAR 180 (Docket No. 71-9325) ................................................................... 52

14. Model No, HI-STAR 60 (Docket No. 71-9336) ..................................................................... 52

15. Model No. BEA Research Reactor (BRR) Package (Docket No. 71-9341) ......................... 53

16. Model No. TN-LC (Docket No. 71-9358) ............................................................................. 54

17. HI-STAR 180D (Docket No. 71-9367) ................................................................................. 55 
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Physical Tests Performed on Spent Fuel Packages 

1. Model No. NAC-LWT (Docket No. 71-9225) 

The information below was obtained from Section 2.10.8 in NAC International, Inc., 

consolidated application dated November 30, 2014 (see Agencywide Documents Access 

and Management System (ADAMS) Accession No. ML15020A548). 

A. Tests performed 

A series of free drop tests were performed on a quarter-scale model of the NACLWT package. Thirty-foot drop test orientations included a vertical top end drop, 

top corner drop at an angle of 15.7 degrees from vertical (center of gravity over 

corner), side drop, and a bottom oblique drop at an angle of 60 degrees from 

vertical. After these tests, the scale model was dropped 40 inches onto a 

puncture pin at the mid-point side of the package. After the tests, measurements 

were performed on the package internal pressure to determine whether the 

containment boundary leaked. 

A series of quasi-static crush tests were performed on quarter-scale models of 

the bottom impact limiter for the NAC-LWT package. These crush tests were 

performed to document the force-deflection and energy absorption 

characteristics of the honeycomb material used in the impact limiter. The limiter 

orientations tested were end (axial), side, and center of gravity over corner 

(15.7 degrees from axial). 

B. Description of the methods or analyses used in tests 

The package was instrumented with nine strain gauges to determine maximum 

bending stresses and maximum plastic strains in the scale model. The strain 

gauges were attached at three axial locations, 120 degrees apart around the 

circumference of the outer surface of the scale model. 

C. Test Results 

Data obtained from the tests consist of both qualitative information with respect 

to observations about the package and the limiter and quantitative data obtained 

from the recorders. The data for each test include measured impact limiter 

deformation, strain gauge data and stress calculations (for the end drop and side 

drop only), and observations of the package and attachments. The strain gauge 

data were only presented for the end drop and the side drop since the loads 

developed in those tests are the most severe from an overall structural 

consideration. The end drop corresponds to the maximum axial loading 

condition, while the side drop developed the maximum lateral loading on the 

overall package body. 

a. Top Drop 

For the top drop the aluminum honeycomb impact limiter was crushed to 

an average depth of 1.2 inches out to a diameter of 7.2 inches. The 
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1.2-inch crush corresponded to an overall crush strain of 33 percent. It 

was also observed that the attachment lugs for the limiter failed; however, 

once the limiter is engaged in the crushing action, the lugs do not provide 

additional functionality in the end drop condition. 

The maximum axial strain observed in the test was 560 microstrains. The 

axial stress is calculated by multiplying the axial strain by the modulus of 

elasticity. The maximum axial stress in the drop is 15.8 ksi, which is 

much less than the yield strength of the material. 

As the limiter was driven onto the package, the test valve used to 

pressurize the interior was broken off, which prevented the pressure from 

being measured after the test. A new valve was installed and the cavity 

was pressurized to 30 psig and was maintained to determine if the 

package containment boundary was damaged. There was no 

measurable pressure loss. The loss of this valve has no implications for 

the full-scale package, since the full-scale version does not have this 

valve. 

b. Top Corner Drop 

For the top corner drop, the maximum amount of crush was 1.38 inches, 

which corresponds to a strain of 38 percent. Similar to the top drop, the 

attachment lugs for the limiter failed; however, once the limiter is engaged 

in the crushing action, the lugs do not provide additional functionality in 

the corner drop condition. 

Based on the pre-test and post-test dimensional measurements, nearly all 

permanent deformation of the packaging model was limited to the impact 

limiters, as expected and desired. The only significant deformation of the 

package body model occurred in the side puncture test, where local 

deformation of the outer shell and the lead shielding did occur. As 

designed, the outer shell was not punctured. This local deformation was 

fully expected and produced a very slight, local dimple in the inner shell 

wall (0.05 in) of the model. These local puncture deformations are of no 

consequence since the containment vessel and its contents are 

protected. Because no deformation to the package was observed, except 

as previously discussed, and the containment vessel sustained 

essentially no deformation, leakage was not expected and did not occur. 

The coupling connected to the valve used to pressurize the interior was 

loosened, which prevented the pressure from being measured after the 

test. The coupling was tightened and the cavity was pressurized to 29.2 

psig and was maintained to determine if the package containment 

boundary was damaged. There was no measurable pressure loss. 

c. Side Drop 

Limiters in the side drop condition were crushed only in regions that are 

backed by the package body. The impact limiters were crushed on both 

the inside next to the scale model and outside where it made contact with 
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the impact surface. The maximum crush on the bottom impact limiter was 

2.64 inches near the package and the minimum was 0.2 inches at the 

bottom. The thickness of the as-built bottom impact limiter is 3.89 inches. 

The maximum crush on the top impact limiter was 1.52 inches and the 

minimum was 0.52 inches at the top. The thickness of the as-built top 

impact limiter is 4.52 inches. 

The maximum axial strain observed in the test was 2500 microstrains, 

which also resulted in a permanent set of 750 microstrains. Due to the 

manner in which the package is loaded, the maximum strains occurred at 

the midpoint. The maximum calculated stress for the side drop is 52.2 

ksi. The pressure in the package was checked prior to the test and 

afterwards. It was found to be 30.4 psig. This indicates that pressure 

containment was maintained during impact. 

d. Bottom Oblique Drop 

In the 60-degree oblique drop test, the maximum crush on the outside of 

the bottom impact limiter is 1.25 inches, and the inside which contacts the 

package is approximately evenly crushed at 1.39 inches. The maximum 

crush on the outside of the top impact limiter is 0.5 inches, and the 

minimum is 0.25 inches. The inside of the impact limiter is crushed 

approximately evenly at 1.5 inches. The pressure measurement 

indicated that the cavity pressure did not change as a result of the oblique 

drop test. Cavity pressure was measured to be 30.2 psig before and after 

the test. 

e. One (1) Meter Puncture test 

As a result of dropping the package body onto the steel pin, the 

containment of the package body was not violated. This was confirmed 

by the pressure measurements before and after the test. All permanent 

strain was local to the region of impact of the pin. The maximum 

deformation of the outer shell was 0.5 inch deep and a localized 

depression of 0.05 inch occurred in the inner shell. Note that the pin 

puncture impact was directed against the portion of the outer shell that 

was stressed most severely in the 30-foot drop tests to show that the 

outer shell retained its puncture capability after the dynamic stress of the 

30-foot fall impact. 

f. Force-Deflection Tests 

Quasi-static force-deflection tests were performed on quarter-scale model 

impact limiters used in drop testing thee quarter-scale model. Limiter 

samples were selected for a particular test based on the limiter having no 

damage for test orientation. Three limiter orientations were tested – 0, 

15, and 90 degrees. While each impact limiter tested was being 

compressed, it was instrumented with two calibrated linear variable 

differential transformers (LVDT) mechanically attached to test fixtures to 

obtain crush force as the impact limiter deformed. Deformation of the 

limiter proceeded well into honeycomb lock-up. As the force on the limiter 
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decreased after the limiter locked up, force and deflection continued to be 

monitored, revealing the amount of elastically stored energy. The static 

force for each data point is multiplied by 1.196, a static to dynamic scaling 

factor, enabling comparison values computed with the RBCUBED 

computer program. 

Forces calculated from the RBCUBED computer program are higher in all 

cases except the end drop. The end drop forces were higher due to a 

shearing previously unaccounted for, causing 10 percent higher forces 

than calculated by RBCUBED. The shearing and shear force generation 

occurs simultaneously with crushing, and is a small force compared with 

the crush force. The average maximum/peak forces and g-loads 

calculated using RBCUBED was compared with corresponding values 

from each of the quasi-static tests. Structural margins are all positive. 

2. Model No. GA-4 (Docket No. 71-9226) 

The information below was obtained from the application dated January 31, 1997 (see 

ADAMS Accession Nos. ML15351A261, ML030860360, ML15351A295, and 

ML030860386). 

A. Tests performed 

1. Honeycomb Impact Limiter Force Deflection Tests 

Four quarter-scale versions of the impact limiter designs were tested at 

different crush angles to provide data on the load-versus-deflection curve 

of the impact limiter. Three impact limiters were tested twice, on opposite 

sides. The tests performed range from end to side crush. The table 

below shows the tests performed. 

Impact Limiter 

No. 

Test on Impact 

Limiter 

Test Crush 

Orientation 

(degrees) 

Energy 

Dissipated 

During Tests 

(lb-in) 

1 1 60 626,178 

2 15 480,743 

2 1 0 (side) 324,570 

2 45 464,708 

3 1 75 689,051 

2 35 218,119 

4 1 90 (end) 717,358 
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2. Half-Scale Model Drop Tests 

The tests consisted of three regulatory test sequences: 

1: Side drop 

• 30-foot side drop 

• 40-inch puncture test in horizontal orientation. 

2: Slapdown 

• 30-foot drop with longitudinal axis at 30° from horizontal 

• 40-inch puncture test in horizontal orientation. 

3: Center-of-gravity (CG) over closure 

• 30-foot CG over closure comer drop with the longitudinal axis 

tilted 12° from the vertical position, 

• 40-inch puncture drop with the longitudinal axis oriented 7° from 

the vertical and the punch striking the closure in the vicinity of the 

gas sample port and closure bolts, and 

• 40-inch puncture drop with the package oriented horizontally with 

the punch striking a longitudinal edge of the model body near midlength at the location of a joint between two depleted uranium 

rings. 

3. Full-scale Closure Seal Tests 

The primary O-ring seal of the package was tested for leakage using a 

full-scale mockup of the package closure and flange. 

B. Description of the methods or analyses used in tests 

1. Honeycomb Impact Limiter Force Deflection Tests 

i. Test Methods 

The tests were performed on a compression testing machine 

using a quarter-scale model of the impact limiters. The impact 

limiters were directly backed by a solid aluminum test fixture. The 

test set-up was instrumented during the entire event to provide a 

complete record of the load applied to the specimen as a function 

of deflection. Graphs of the load-versus-deflection data were 

produced. 

2. Half-Scale Model Drop Tests 

i. Tests Conditions 

All tests were performed at ambient temperature. The initial 

pressure in the model's fuel cavity was 80 psig (0.55 mpa). The 

model was not disassembled or parts replaced during any test 
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sequence. Impact limiters, impact limiter bolts, and closure seals 

were replaced after each sequence. 

ii. Test Methods 

GA constructed a concrete and steel drop pad that meets 

International Atomic Energy Agency’s guidelines for an unyielding 

surface. For puncture events, a 3-inch diameter mild steel 

puncture pin was bolted to the pad. 

Prior to any testing, the model was marked to locate the exact 

points at which the measurements were to be taken. For each 

drop, the model was rigged in the proper orientation, lifted to a 

height of 30 ft (or 40 inches for the puncture tests) by a crane, and 

released by simultaneously firing multiple explosive cable cutters. 

Triggering of the high speed cameras and the strain gage and 

accelerometer data acquisition system was synchronized with the 

cable cutter firing. 

The closure O-ring seals and the gas sample port seals were leak 

tested before and after each test sequence. The impact limiters 

were inspected after each test to determine the damage caused 

by the test. Dimensional checks and helium leakage tests of the 

containment boundary and cavity liner were performed on the 

model package after all testing was completed. 

The dimensional measurements included are overall length 

measurements and package body profile. Complete dimensional 

checks were performed before and after testing was completed. 

The model was disassembled and all the removable parts 

inspected. The fuel support structure was not removed from the 

cavity. 

3. Full-scale Closure Seal Tests 

i. Test Conditions 

Four tests were performed at temperatures of ambient, -42 oF, 

250 oF, and 380 oF. Shim plates between the fixture lid and 

flange, ranging from 0 to 0.038 in., simulated gaps resulting from 

thermal-induced distortion. The leakage testing was carried out 

by means of a helium mass spectrometer leak detector, following 

the guidelines in American National Standards Institute American 

National Standards Institute (ANSI) N14.5-1987, “Radioactive 

Materials - Leakage Tests on Packages for Shipment.” 

ii. Test Set-up 

The test fixture consisted of a lid and flange and was a full-scale 

representation of the cross section of the package closure end. 

Two dovetail grooves in the lid held the primary and secondary O-
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ring seals. The grooves and O-ring seals precisely modeled the 

full-scale package. All fixture materials were fabricated from 304 

stainless steel. The fixture lid weighed approximately 170 lb. and 

the flange 180 lb. The fixture lid was attached to the flange with 

twenty, 1-inch bolts that thread into nuts tack-welded to the bottom 

of the flange. The bolts were torqued to 100 ft-lb. Shim plates 

extending all around the fixture's perimeter maintain uniform 

specified gaps between the lid and flange. 

From operational and handling considerations it was not feasible 

to fabricate the test lid to the actual closure thickness of 11 inches. 

Since the test was a verification of the seal performance under the 

actual temperatures and amounts of compression experienced in 

the package, seal and groove dimensions were identical to those 

in the package. The number of bolts was increased from 12 to 20 

in the test only to minimize local deflection between bolts of the 

relatively thin 1-in. lid. This local deflection is absent in the actual 

package due to the considerably thicker and stiffer lid. The bolt 

torque in the test was less than actual (100 versus 235 ft-lb) but 

the seals are fully compressed in both the test and package 

configurations. Once the seals are fully compressed in their 

grooves and metal-to-metal contact is established, additional bolt 

torque produces no further compression of the seals. For the 

reduced compression predicted by the accident analysis, shims of 

a known thickness were inserted between the lid and its base to 

duplicate this effect. 

Prior to testing, the small volume between the flange and lid is 

initially evacuated. When the test begins, this volume is filled with 

helium to atmospheric pressure. A second port located between 

the O-rings is continuously evacuated by the helium mass 

spectrometer leak detector, and the detector measures the helium 

leakage past the primary (inner) O-ring. The detector output is 

recorded by a conventional strip chart recorder. 

For the tests carried out in the conditioning chamber, the fixture 

temperatures near the inner seal are measured by two 

thermocouples (Type T) and recorded. 

C. Test Results 

1. Honeycomb Impact Limiter Force Deflection Tests - Comparison of Test 

and Analytical Results. 

The largest differences between the test and analytical results occur 

during the end crush. The test showed a higher initial crush load, 

dropping to the analytical value later in the crush. The higher load is 

partly attributable to the buckling of the impact-limiter-bolt guide tubes in 

the end of the impact limiter. To reduce this tube buckling load, GA 

changed the tube material from 1/8 hard Type 304 stainless steel with a 

yield of 90 ksi to 304 Stainless Steel annealed with a minimum yield of 
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30 ksi. In addition, the tube wall thickness was decreased from .07-inchthick to .035-inch-thick. This change reduces the guide tube buckling 

loads to a level that is small compared to the honeycomb crush load, 

while still maintaining the necessary energy absorption capability during 

an end crush. The remaining difference between test and analytical 

results is ignored, since the design margins for the package and neutron 

shield structure for the 1-ft end drop are high. 

The crush forces from the 30o test are lower than the data calculated in 

ILMOD. (ILMOD is a GA developed computer code to compute the load 

versus deflection curves for impact limiters with standard unidirectional 

honeycomb.) This is almost certainly due to the fact that this was the 

second test of the impact limiter and the first 75o test weakened the 

impact limiter. After the 75o test, the outer diameter of the impact limiter 

had grown from 22.48 in. to 23.06 in. 

The remaining difference between test and analytical results is ignored 

since the design margins for the package and neutron shield structure for 

the 1-ft end drop are high. 

2. Structural Tests 

The performance of the half-scale model showed the GA-4 package 

design to be robust. No permanent deformation of the model body 

occurred except local dents from the puncture attacks. The fuel support 

structure remained in its keyway attachment to the liner. The cavities 

formed by the fuel support structure and cavity liner had no permanent 

deformation except a local indentation of 0.07 in. at the location of the 

puncture in Sequence 2, Test 2. The model held its full 80 psig (0.55 

mPa) internal pressure and remained leaktight (helium leakage less than 

1 x 10-7 std cm3/s) throughout all seven tests. 

(Note: The analyses show that the maximum neutron-shield-fluid 

pressure is 416 psi for a 30-ft end drop at the maximum temperature 

condition. This pressure includes the increase in pressure due to thermal 

expansion of the fluid. The analyses show that the ILSS top and bottom 

end plates can withstand this pressure and meet all design requirements. 

During a 30-ft drop, the effect of the fluid pressure is to act opposite to the 

impact limiter loads and thus will reduce the loads on the ILSS outer shell. 

Because it is less than the impact force, it may be conservatively 

neglected.) 

i. Side Drop 

• Sequence 1, Test 1; 30-ft Side Drop 

Using a mobile crane, the model was lifted to a height of 30 ft. 

above the pad with the package body oriented horizontally and 

the longitudinal edge of the package marked 225o facing the 

impact surface. The model released cleanly and did not rotate 
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or yaw significantly during its descent. Time to impact from 

release for all 30-ft drops is 1.4 seconds. 

• Sequence 1, Test 2; Puncture at Side of Closure 

This test was a puncture drop from a height of 40 in. with the 

model oriented horizontally and the punch striking the model 

package's structure adjacent to the corner of the closure end. 

The puncture pin itself was observed to be in good condition 

after the test. Some of the white paint was scraped off by the 

honeycomb, but no permanent deformation of the pin was 

visible. 

ii. Slapdown Sequence 

• Sequence 2, Test 1; 30-ft Slapdown 

For this test new impact limiters were installed and the model 

was rigged with its axis tilted 30o from the horizontal position. 

The model was dropped with the closure end striking first, and 

the flat side marked 90o facing the impact surface. The 

closure end impact limiter crushed a maximum of 7.5 in. The 

model rotated and crushed the bottom end impact limiter 7.9 

in. Final orientation of the model on the pad was 3o from 

horizontal with the closure end sitting slightly higher than the 

bottom end. 

• Sequence 2, Test 2; Puncture at Package Body Flat Side 

Since the puncture pin hit the body directly on the flat side, this 

event was a severe test of the package body integrity. Both 

the model and the pin experienced local permanent 

deformation. The dent on the package body was a maximum 

of 0.15 inches deep. An examination of the model interior 

revealed that a small amount of permanent deformation had 

been transferred to the cavity liner and locally to the edge of 

one plate of the fuel support structure. The deformation of the 

cavity was measured as 0.07 inches. No other deformation of 

the fuel support structure or liner was observed. 

An internal pressure of 80 psig was maintained for sequence 

2. The helium leakage test showed that the seals maintained 

a leaktight condition for the sequence. 

iii. CG-over-closure-corner sequence 

• Sequence 3, Test 1; 30-ft Drop, CG-over-closure-corner. 
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This test was a CG-over-closure-corner drop from 30 ft. with 

the model axis tilted 12o from the vertical position and a 

longitudinal edge of the model facing the impact surface. 

Both impact limiters stayed attached to the model package. 

The closure end had been fitted with a new impact limiter but 

the bottom end limiter was reused from a previous test. 

• Sequence 3, Test 2; Puncture at Closure Bolt and Gas Sample 

Port. 

This test was 40-inch puncture drop with the model oriented 7o 

from the vertical and the puncture pin striking the closure in 

the vicinity of the gas sample port and closure bolts. 

The objective of this puncture test was to test the integrity of 

the closure bolts and the gas sample port and cover. The 

post-sequence examination showed that the puncture pin 

completely compressed the aluminum honeycomb in its path 

and dented the impact limiter housing. Some visible local 

deformation was transferred to the gas sample port cover, 

damaging the first few threads of the screwed on cover. Due 

to the damaged threads, the port cover had to be partially 

drilled out with a hole saw in order to be removed. With the 

cover removed, it was observed that the quick-connect nipple 

was undamaged. The post-sequence pressure check of the 

cavity and helium leakage test of the seals confirmed that this 

puncture attack did not cause a breach of the containment 

boundary. 

• Sequence 3, Test 3; Puncture at a depleted uranium joint. 

The final test was another puncture drop with the model 

oriented horizontally, and the punch striking a longitudinal 

edge of the body near mid-length at the location of a joint 

between two depleted uranium rings. 

After the completion of the final test, the closure seals were 

leak tested to assess the condition of the liner and the model 

package body. Both the liner and the model package body 

were found to be leaktight. 

3. Full-scale Closure Seal Tests 

Four tests were carried out with the ethylene propylene seals. One set of 

seals was used for the test at -40oF, and another set was used for the 

other three tests. The first two tests simulated normal conditions of 

transport, while the last two represented hypothetical accident conditions. 

For the latter conditions, the thermal and thermal stress analyses predict 

a maximum lid/flange gap of 0.024 inches, corresponding to a seal 
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temperature of 240 oF, while 300 oF is the maximum seal temperature, 

corresponding to a zero gap. The conditions used in the test are 

therefore conservative. 

GA tested the seal and found it to be leaktight (<1×10-7 ref cc/sec as 

defined by American National Standards Institute (ANSI) N14.5, 

“Radioactive Materials - Leakage Tests on Packages for Shipment”) at 

-42 oF, ambient (-75 °F), and 250 oF. The maximum calculated 

temperature of the seals is 135 oF in the closure and 143 oF for the drain. 

For hypothetical accident conditions the analysis shows that the maximum 

primary seal temperature is 300 oF. This includes the closure seal and the seal 

for the gas sample and drain ports. Manufacturer's data indicate the seal 

material can withstand a temperature of 350 oF for 50 hours and 400 oF for 

several hours. Using conditions more severe than those predicted by the 

analysis, the applicant tested the seal at 380 oF, after heating for 1.5 hours above 

350 oF, and determined it to be leaktight. Therefore, the seal will function during 

the hypothetical accident thermal event. For the post-accident steady-state 

condition the maximum temperature of any seal is 175 oF. 

3. Model No. 2000 (Docket No. 71-9228) 

The applicant used finite element and other calculation methods as part of the structural 

evaluation. A thermal test has been conducted on the Model 2000 transport package to 

verify the thermal analytical model by comparing the analytical results to those of the 

physical testing. 

The information below was obtained from Chapter 4 of the application dated December 

2000 (see ADAMS Accession No. ML063650011). 

A. Tests performed 

A thermal test has been conducted on a GE Model 2000 package. The objective 

of the test is to verify the thermal analytical model by comparing the analytical 

results to those of the physical testing. The testing is done at ambient conditions 

with 600 and 2000 watts heat input in the package cavity to simulate the 

maximum decay heat. The test also demonstrates the capability of the Model 

2000 to safely dissipate 600 and 2000 watts of decay heat. 

B. Description of the methods or analyses used in tests 

The thermal test was performed by placing an electric heat source concentrically 

within the cavity. Thirteen temperature sensing devices were placed within the 

cavity, on the external surfaces of the package, and on the overpack surfaces. In 

the radial direction, temperatures measured included the package cavity air, 

internal package wall, external package wall, overpack inside surface, and the 

overpack external surface. In the axial direction, the temperatures measured 

included the package cavity floor, the bottom package surface, below the lower 

honeycomb pad, at the bottom of the overpack, at the top of the package cavity 

(under the lid), at the gasket lower surface, at the top of the lid, and at the top of 
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the overpack. Three additional transducers recorded the external ambient 

temperature. The temperature data were recorded at 30 minute intervals during 

the transient until a steady state condition was reached. Temperatures remain 

significantly unchanged for a one hour period. 

C. Test Results 

Differences between the test and the model temperatures were 3% in the 

package cavity, 1% at the package outer wall, 5% at the overpack inner wall, and 

1% at the overpack outer wall. Test data and the LIBRA predictions of cavity wall 

temperature versus time for the 2000 watt case were plotted in Figure 3.35: 

excellent correlation between test and analysis results is displayed. The physical 

test confirmed the adequacy and accuracy of the model used in the LIBRA finite 

element thermal analysis code for the 2000 package. 

4. Model No. NAC-STC (Docket No. 71-9235) 

The information below was obtained from Section 2.10.6 in NAC International’s 

consolidated SAR (see ADAMS Accession No. ML112301077) for the impact limiter 

tests. 

A. Tests Performed 

The scale model test program for the directly loaded fuel configuration of the NAC-STC 

included: (1) quarter-scale model drop tests, and (2) eighth-scale model impact limiter 

quasi-static compression tests. 

1. Dynamic Impact Limiter Tests 

The objective of the quarter-scale model drop tests was to confirm the 

design of the NAC-STC packaging through a series of tests conducted at 

the Winfrith Technology Centre drop test facility located in the United 

Kingdom. The planned tests included: 

• 9-meter (30-foot) top end drop, 

• 9-meter (30-foot) top corner drop (24 degrees from the vertical), 

• 9-meter (30-foot) side drop, 

• 9-meter (30-foot) bottom end oblique drop (75 degrees from the 

vertical), 

• 1-meter (40-inch) pin puncture drop at the cask axial mid-point, and 

• 1-meter (40-inch) pin puncture at the center of the outer lid. 

When testing commenced, the model employed aluminum shell impact 

limiters. After completing the first three tests above, testing was 

suspended to effect repairs to the model. Therefore, these three tests 

were identified as Phase 1. After repairs were completed, it was decided 

to perform the fifth and sixth puncture tests above and identify these tests 

as Phase 2. During the performance of these tests, however, the 24-inch 

long pin deformed excessively, to the extent that maximum damage was 

not inflicted on the cask body or the outer lid. Therefore, it was 
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determined that the pin puncture tests would be re-performed using an 

8-inch tall pin. 

Testing resumed after replacing the aluminum shell impact limiters with 

stainless steel shell impact limiters. In addition, the planned tests to 

confirm the cask design was changed to the following: 

• 9-meter (30-foot) side drop, 

• 9-meter (30-foot) 75 degree oblique bottom end drop, 

• 9-meter (30-foot) top corner drop (24 degree), 

• 9-meter (30-foot) 75 degree oblique top end drop, 

• 1-meter (40-inch) drop cask mid-point pin puncture, and 

• 1-meter (40-inch) drop outer lid center pin puncture. 

Performance of these six drop tests constituted Phase 3 of the drop test 

program. As a result of the side and 75 degree oblique bottom end drop 

tests performed in Phase 3, it was determined that the redwood in the 

overlap region of the impact limiter was not maintaining its original 

position and orientation. A design modification was added to the overlap 

region of the impact limiter to prevent the redwood in that region from 

changing its orientation during the side impact. After repairing pin 

puncture damage to the inner shell of the model cask body, both a 

9-meter (30-foot) bottom oblique and 9-meter (30-foot) side drop test was 

performed. These two tests made up Phase 4 of the drop test program. 

2. Static Impact Limiter Test Information 

A series of quasi-static compression tests were performed to simulate an 

end impact, a corner impact, and a side impact using eighth-scale model 

redwood/balsa wood impact limiters. The static compression tests were 

performed to demonstrate that force-deformation curves are as predicted 

by analytical methods, energy storage (rebound) in the crushed 

redwood/balsa wood impact limiters is negligible, and the geometry of 

both the impact limiter and cask body effectively causes the impact limiter 

to stay attached to the cask. 

Based on the results of the quasi-static tests, the force-deformation curve 

and the energy absorption capacity (area under the curve) of each model 

impact limiter was determined. The force-deformation curve is measured 

by compressing the model impact limiter and recording the deflections 

and loads applied to the limiter. The energy storage, or rebound, of the 

model impact limiter is shown by the load-deformation curve as the test 

machine is unloaded slowly. The model impact limiter presses against 

the test machine heads and applies a load proportional to the elastically 

stored energy. This extra energy component can be restored to a cask in 

a multiple-impact, oblique drop "slap down" scenario. 
- 14 - 

B. Description of the methods used in tests 

1. Dynamic Impact Limiter Tests 

The quarter-scale model packaging was an exact replica of the full-scale 

design with two exceptions: (1) O-rings in the inner and outer lids were 

not scaled; and (2) the neutron shield was not modeled, but the weight of 

the neutron shield was modeled by steel blocks welded to the outer shell. 

All aspects of the model can be used to reflect the strains, accelerations, 

and impact limiter crush strokes of the full-scale design. With respect to 

containment, the model represents the geometrical arrangement and 

materials used in the full scale design. However, the O-ring dimensions 

and the leak rate cannot be scaled. Therefore, the pressure 

measurements can only be used to indicate the condition of the seals and 

the adjacent seating surfaces. The initial scale-model design used impact 

limiters with aluminum shells. However, due to poor performance, the 

aluminum shells were replaced with stainless steel shells after the first 

several drop tests. 

Ninety-degree tee-rosette strain gauges were mounted on the cask body 

for all of the drop tests. One gauge of each tee-rosette was positioned in 

the axial direction and another in the circumferential direction. These 

strain gauges allowed the axial and the hoop stresses to be determined. 

Later in the testing program, the 90-degree tee-rosettes at two locations 

were replaced with rosettes with three gauges at 45-degree orientations. 

This allowed the shear stresses to be determined at the surface. All 

gauges had at least a 50 kHz response time to ensure that the transient 

strains could be accurately recorded. Real-time recording was 

accomplished by a system of strain amplifiers, signal conditioners and a 

magnetic recording unit to store the data. 

Accelerometers which could measure accelerations up to 20,000 g with 

an accuracy of 1 percent per 2,000 g were employed for the drop tests. 

Since an acceleration level of only 300 g was expected, the test accuracy 

was + 0.5 g. The frequency response of the accelerometer was between 

2 Hz to 15,000 Hz. which enveloped the frequency of the system. All 

accelerometer data were conditioned and stored on magnetic media for 

later processing, which included filtering and integrating to obtain impact 

velocities. 

Two high-speed cameras were used to record the behavior of the quarterscale model as it impacted the target surface. For the top end drop, both 

cameras were operated at 500 frames/sec. and the cameras were 

positioned 90 degrees apart (side and end views). For the final top 

corner drop, side drop, and oblique slap down drop, one camera was 

positioned to capture the overall motion of the cask at 500 frames/sec. 

and the other camera was set to obtain a close-up view of the crushing of 

the impact limiter at 1000 frames/sec. 
- 15 - 

2. Static Impact Limiter Test Information 

Eighth-scale tests were performed with lower impact limiters primarily 

because the trunnion cutouts in an eighth-scale model upper impact 

limiter are extremely difficult to fabricate using the scaled shell thickness. 

This was determined to be acceptable because previous analyses, scale 

model compression tests, and scale model drop tests demonstrated that 

the trunnion cutout regions of the upper impact limiter do not significantly 

affect the energy absorption capability of the impact limiter. Initially, the 

model impact limiters were fabricated from aluminum alloy. However, 

during the quarter-scale drop test program, the model design was revised 

to use 0.031-inch stainless steel to fabricate the impact limiter shells. The 

impact limiter models used in the static tests represented the revised 

configuration. Like the full-scale design, the eighth-scale models used 

redwood/balsa wood as the energy absorbing materials. 

The eighth-scale model impact limiters were crushed quasi-statically in a 

tensile test machine capable of also applying compressive loads. The 

tensile test machine capacity limited the maximum size of the test impact 

limiter to one-eighth scale. The eighth-scale model impact limiters were 

not attached mechanically to the cask-shaped test fixtures. Duct tape 

was used to hold the model impact limiter in place while the compressive 

test load was applied. The tape relaxed as successively higher loads 

were applied, demonstrating that the impact limiter geometry produces 

net crush forces that press the impact limiter against the cask body, 

regardless of the impact angle. 

While each model impact limiter tested was being compressed, two 

calibrated linear variable differential transformers (LVDT) mechanically 

attached to test fixtures provided data to an X - Y recorder, which plotted 

crush force versus deformation. Deformation of the model impact limiter 

proceeded well into the compression lock-up range of the redwood. As 

the compression load on the model impact limiter was decreased after the 

test was stopped, force and deflection continued to be monitored, 

revealing the amount of elastically stored energy. The static force for 

each data point is multiplied by 1.06, a static to dynamic scaling factor, 

enabling a direct comparison with the analytically computed values. The 

dynamic scaling factor was determined from Figure 9 of NUREG/CR0322, “The Effects of Temperature on the Energy-Absorbing 

Characteristics of Redwood,” which is based on Sandia National 

Laboratories tests. 

C. Test Results 

1. Dynamic Impact Limiter Tests 

The acceptance criteria for the cask body performance is that cavity 

pressure be maintained and that the fuel remain in a subcritical 

configuration. For the cask body, this requires that permanent 

deformation must not occur to the lids, the lid mating sealing surfaces, the 
- 16 - 

fuel basket and the lid bolts (both inner and outer) after completion of the 

drop tests. 

The impact limiters must limit the deceleration of the cask body and 

components during a cask drop event. Therefore, the impact limiter 

acceptance criteria requires that the crush stroke be limited to prevent the 

cask body from contacting the impact surface, the accelerations be 

limited to those used in the design analyses, and the impact limiters 

remain attached to the cask body and in position after the impact event. 

To assess the model performance against the acceptance criteria, the 

following data was collected for each test: 

• Metrology data - to assess the permanent deformation of the cask 

body, fuel basket, lid seating areas, or in the lids themselves. 

Measurements for all dimensions except the inner diameters in the 

lower portion of the model cask cavity were obtained in a lab before 

and after the tests. The tolerance for all measurements was + 0.001 

inch. 

• Pressure and temperature data - to assess the retention of pressure 

by the cask primary containment boundary, the cask cavity was 

pressurized to 30 (+2,-0) psi using a pressure port located near the 

model cask midpoint. The pressure in the cask cavity was measured 

before and after each test. To assist in correlating the pressure 

change with a change in the cask temperature, the temperature of the 

cask body was also obtained by Chromel/Constantan thermocouples 

attached to the cask exterior near the pressure port used to 

pressurize the cavity. 

• Strain data - strain time-histories were recorded for each of the 30-

foot drops to determine the maximum amount of strain experienced by 

the cask body. Stress data were mathematically derived from the 

strain gauge data. Strain gauge data were only taken for the 30-foot 

drop tests. It was concluded that the strain gauge data were not 

needed for the pin puncture drops. 

• Acceleration data - to determine the maximum accelerations to which 

the cask was subjected, two single-axis accelerometers were 

mounted on the cask body for each of the 30-foot drop tests. The 

directions were altered for each individual test to ensure that the 

vertical deceleration was measured. Acceleration data were only 

taken for the 30-foot drop tests. It was concluded that the 

accelerometer data were not needed for the pin puncture drop tests. 

• Impact limiter deformation data - to evaluate the behavior of the 

impact limiters, the crush stroke for each orientation, and the condition 

of the limiter attachment to the cask body after each test, the limiters 

were inspected to determine the amount of deformation that had 

occurred after each test. In addition, the condition of the attachment 
- 17 - 

rods and nuts was also determined. Photographs of the deformed 

limiters were taken to record the post-test condition of the limiters. 

• High speed photography - to review and assess the actual angle of 

impact and the behavior of the cask body and impact limiters during 

the impact. 

i. Thirty-Foot Top End Drop Using Impact Limiters with Aluminum 

Shells - Test No. 1 of Phase 1 

This was the first drop test to be performed of the four phases of 

tests using the quarter-scale cask model. The impact limiters 

used the aluminum shell design, which weighs less than the 

stainless steel shell design used in later tests. The cask model at 

the time of the top end drop was within 0.5 percent of the design 

weight of 3906 pounds (250,000/43 pounds). 

Essentially all of the crushing occurred within the backed region of 

the impact limiter. The crush deformation was 2.11 inches, 

corresponding to a crush strain of 23 percent. The maximum 

stress was 8.6 ksi. The hoop strain component was extremely 

small. All three gauge locations near the top showed similar 

behavior in the axial and the hoop direction. One of the strain 

gauges showed a maximum permanent strain of 0.0015 percent. 

Since the normal stresses are so low, this offset is not attributed to 

any yielding of the material. Two accelerometers were mounted 

180 degrees apart at the top end of the cask model. The 

maximum acceleration obtained from a 1000 Hz filtering of the 

accelerometer trace was 247 g. This value corresponds to a fullscale acceleration of 62 g. The filter frequency was computed by 

considering the first longitudinal vibrational mode, fl, of the model 

as determined using an expression from Blevins for a lump mass 

attached to a cantilevered beam. The pressure measured after 

the test showed a slight increase, which corresponds to the small 

increase in the cask body temperature. Since the temperature 

data cannot be expanded to determine the temperature of the 

cavity gas, an accurate calculation of the corresponding increase 

in the pressure cannot be made. The pressure measurements 

indicate that there was no loss of pressure. After the top end drop 

test, the basket was removed from the cask body to inspect for 

deformations. The fuel basket was removed without any 

interference and neither the fuel basket nor the dummy fuel 

assemblies had deformed. This indicates that out of plane 

buckling due to the vertical deceleration loads did not occur, and 

that buckling of the inner shell due to lead slump did not occur. As 

evidenced by the nearly uniform crush of the impact limiter and 

the data from the two axial accelerometers, the load on the lead 

was essentially uniform around the model circumference. Thus, 

yielding of the inner shell at one location on the circumference 

would have precipitated yielding of the larger shell around the 

entire circumference. However, there was no evidence of yielding 
- 18 - 

in the lead, basket, lids, or bolts used in the model. This test 

satisfactorily verified the packaging design for the nine-meter (30-

foot) end drop. 

ii. Thirty-Foot Side Drop Using Impact Limiters with Aluminum Shells 

- Test 3 of Phase 1 

The high speed film showed that the welds along the edges of the 

aluminum limiters failed immediately upon impact, which allowed 

the four steel blocks at the lower edge of the cask to strike the 

impact surface. The force to decelerate the cask model was 

concentrated at the four steel blocks. The energy was absorbed 

by the local deformation of the model cask body shells and the 

model fuel basket. Based on the high-speed film, the rebound of 

the cask body was small, indicating that essentially all of the 

energy was absorbed in the initial impact. As a result of the 

localized loading on the cask body shells, the top forging, which 

serves as the seat for the lids, was deformed and the internal 

cavity pressure was not maintained. However, the lids remained 

firmly attached to the cask body during and after the impact. This 

test served to describe the behavior of the cask body in a 

guillotine-type impact without a neutron shield. 

Strain gauge data were recorded at nine locations. A permanent 

strain in both the hoop and axial directions was identified. 

Therefore, an equivalent plastic strain (eeq) was computed based 

on the Von Mises and Prandtl-Ruess Flow Rule material 

representation for material yielding to assess the amount of workhardening undergone by the material. The maximum value found 

was 1811 microstrains, or 0.18 percent, at the midpoint of the 

cask at the point nearest the impact plane. Two strain gauges 

were approximately 0.25 inches from the edge of the blocks, 

which were displaced into the outer shell. This implies that the 

strain gauges were able to reflect the maximum strains generated 

by the impact. 

The maximum accelerations recorded were 996 g and 1190 g. 

The first six or seven milliseconds correspond to the crushing of 

the redwood, after which the large increase in the deceleration is 

due to the steel blocks striking the impact surface. 

The radial deflection was greatest at the lid end of the cask. The 

inner radius was decreased by 0.126 inches at the point of impact 

(the 0-180 degree diameter). The impact also caused out-ofround deformation of the cask at other measured locations by 

approximately 0.06 inches to 0.09 inches on a radius. 

The inner and outer lids were inspected for out-of-plane 

deformation, and the measurement of the out-of-plane dimensions 

showed that no deformation had occurred during the Phase 1 

tests. 
- 19 - 

The deformation of the model cask body required that the fuel 

basket be partially disassembled in the cask cavity in order to 

remove the basket after the side drop test. Two support disks 

were damaged in the drop test. One support disk had been 

loaded by the steel blocks, and the other support disk was located 

at the axial center of the basket. The out-of-plane measurement 

for the support disk located at the axial center of the basket was 

0.001 inch, which is the sensitivity limit of the equipment. In 

addition, the support disk at the axial center of the cask did not 

experience plastic deformation. For the support disk loaded by 

the steel blocks, the maximum variation in the direction 

perpendicular to the plane of the disk was 0.004 inch. The impact 

also caused deformation to the bottom of the support disk. The 

impact of the steel blocks into the cask body and basket resulted 

in the lateral movement of the lower four fuel assembly positions 

by 0.19 inches. In addition, none of the support disks exhibited 

any out-of-plane buckling. 

The deformation of the fuel basket near the steel block is not 

classified as buckling deformation, but rather deformation imposed 

by the impact of the steel blocks. Before proceeding with further 

testing, damaged components were repaired to meet the model 

drawing specifications and a new basket was installed. Since the 

inner shell was subjected to a small degree of work-hardening, the 

yield strength changed slightly. 

The change in the yield strength is estimated by the product of the 

tangent modulus (Et) and the eeq strain determined from the drop 

test. From NUREG/CR-0481, “An Assessment of Stress-Strain 

Data Suitable for Finite-Element Elastic-Plastic Analysis of 

Shipping Containers,” for Type 304 stainless steel, Et is 370,000 

psi. Multiplying 370,000 by 0.18 percent, the yield strength 

increased by approximately 700 psi. The 700 psi change 

corresponds to a change of about 2 percent for Type 304 stainless 

steel at 70 °F. This change is considered to be insignificant. 

Although this test demonstrated that aluminum welds are 

inadequate to maintain the integrity of the impact limiter, this test 

clearly demonstrated the strength of the fuel basket design. 

iii. Thirty-Foot Top Corner Drop Using Impact Limiter with Stainless 

Steel Shells - Test 3 of Phase 3 

For the top corner drop test, the cask axial centerline was oriented 

24 degrees from the vertical. This corresponded to the center of 

gravity of the cask being over the edge of the impact limiter. 

The high speed film and the shape of the crushed impact limiter 

indicated that a small amount of impact limiter rotation occurred 

during the top corner drop. As the crushing was initiated, a force 

couple was applied to the impact limiter by the crushing force at 
- 20 - 

the edge of the impact limiter and by a force due to the edge of 

the cask bottom moving into the impact limiter. This force couple 

resulted in rotation of the impact limiter away from the cask 

bottom, which produced the appearance of two crush faces on the 

bottom of the impact limiter. Initially, the crushed surface of the 

bottom of the impact limiter was at a 24-degree angle with respect 

to the uncrushed portion of the limiter (corresponding to the corner 

drop angle). 

During the impact, the impact limiter shifted slightly and the angle 

became smaller. The maximum permissible deformation was 

assumed to be the distance from the edge of the redwood at the 

corner of the limiter to the edge of the limiter nearest the edge of 

the cask bottom. This was to ensure that the cask corner did not 

impact the unyielding surface. 

The crush stroke for the corner drop was significantly larger than 

that for the end drop, since the crush area for the corner drop 

initially started out as a point and increased to the maximum area 

of 350 square inches. For the end drop, the crush area remained 

constant at 477 square inches. The decreased crush area and 

crush force in the corner drop resulted in a much larger crush 

stroke. 

Although strain data were recorded for all locations, the data for 

some locations was inadvertently destroyed during postprocessing. The maximum axial strain for the top end drop was 

90 inch/inch, and maximum axial strain for the top corner drop 

was 63 inch/inch. With the exception of one axial strain 

measurement taken near the bottom of the cask, which was away 

from the point of impact, all axial strain measurements for the top 

end drop exceeded the axial strain measurements for the top 

corner end drop. Thus, the data confirm that the top end drop 

axial load envelopes the top corner drop axial loads. Therefore, 

the maximum stress computed for the data obtained in the top end 

drop, 8.6 ksi, envelopes the maximum stress that occurs in the top 

corner drop. The maximum acceleration was 127 g. 

The trace reflects the gradual increase of the impact limiter 

crushing area. As the impact limiter crush area increases, the 

deceleration force also increases. Since the dynamic modes of 

deformation are similar to those for the end drop, the cut-off 

frequency used for the top end drop is applicable for the top 

corner drop. The data for this test were also filtered at 4000 Hz to 

demonstrate the effects of using higher filter frequencies. In 

comparing the top corner drop to the top end drop, the top corner 

drop produces significantly lower accelerations. 

There are two reasons for this. First, the total crush area for the 

top end drop was 477 square inches while the top corner drop 

utilized 350 square inches. Additionally, the top corner drop does 
- 21 - 

not subject the redwood to a uniform strain, but rather the top 

corner drop crush strain varies from a maximum value to zero. 

The cavity pressure measured after the top corner drop test 

showed a decrease of 0.2 percent due to a 1.5°F decrease in the 

cask body temperature. The pressure measurements indicate 

that the cavity pressure was maintained during the test. The lids, 

lid bolts, basket and fuel assemblies were removed and no 

damage to any component was observed. This test satisfactorily 

verified the packaging design for the nine-meter (30-foot) top 

comer drop. 

iv. One-Meter Pin Puncture Drops - Tests 5 and 6 of Phase 3 

In preparation for the pin puncture tests, the fuel basket was 

removed to prevent it from supporting the cask shells during the 

pin puncture tests. Bags of lead weights were placed in the model 

cask cavity to simulate the weight of the components that were 

removed. 

A pin puncture test was performed at the axial midpoint of the 

cask, and a second pin puncture test was performed at the center 

of the outer lid. For the cask mid-point pin puncture test, the pretest pressure was 3.007 bar and the post-test pressure was 

3.002 bar. This pressure drop was attributed to the 7.2 degree 

drop between the pre-test and post-test cask temperature 

measurements. 

In the cask outer lid pin puncture event, the cavity pressure valve 

cracked allowing the cavity pressure to decrease. (The cavity 

pressure valve in the model serves only as a convenient fixture to 

pressurize the model cavity, and is not a part of the full-scale 

NAC-STC design.) The cask was refitted with another valve and 

the cask was re-pressurized to 3.1997 bar. At the end of 

10 minutes the pressure was still at 3.1995 bar, indicating that the 

closure lid system had performed satisfactorily. 

The cask mid-point pin puncture resulted in an indentation of 

0.33 inch in the outer shell. This did not result in penetration of 

the outer shell. The test, however, did result in deformation of the 

pin itself, but the effect of the deformation of the 8-inch long pin is 

considered to be negligible. 

For the outer lid pin puncture test, the pin was found to have 

impacted at a location 2.53 inches away from the true center. 

This corresponds to approximately 10 percent of the diameter, 

and would produce essentially the same result as if it were at the 

exact center. The metrology data indicate no permanent 

deformation of the outer lid for the pin puncture condition at the 

off-center location. A pin puncture at the center would not be 

expected to result in permanent deformation of the closure lids 

either. Some minor scraping of the outer surface of the outer lid 
- 22 - 

was also noted. Performance of these tests satisfactorily verified 

the packaging design for the pin puncture events. 

v. Thirty-Foot Bottom Oblique Drop (Top End Slapdown) using 

Modified Impact Limiters with Stainless Steel Shells - Test No. 1 of 

Phase 4 

In this test, the bottom of the cask impacts first causing the top 

end of the cask to rotate (and slap down). For a shallow angle 

oblique impact (near side impact), the slap down impact usually 

will result in a higher acceleration than for a side drop due to the 

angular momentum of the rotating cask. The high-speed film 

verified that the model orientation angle was 75 degrees from the 

vertical. It is required for the quarter-scale model that the 

maximum crush stroke be less than 3.22 inches to prevent the 

neutron shield from contacting the impact surface. 

In the top end slap down, the maximum crush stroke occurred in 

the top limiter, which was subjected to the slap down effect and 

was determined to be 2.41 inches. The maximum stress occurred 

at the top end impact limiter at the 180 degree location. While 

some permanent strain was recorded, the level was significantly 

less than 0.2 percent. The maximum acceleration occurred at the 

top end of the cask and was approximately 10 percent greater 

than that at the lower end. The peak acceleration value, 225 g, 

was measured using a filter frequency of 750 Hz to avoid 

artificially inflating the acceleration levels because of higher 

frequency signals associated with the instrumentation. 

The pressure measured before and after the test remained 

constant to within the accuracy of the instrumentation indicating 

that no loss of pressure occurred during the test. The metrology 

data indicate that, for a measurement tolerance of 0.01 inch, none 

of the diametral dimensions changed. No resistance was 

encountered when removing the basket. Performance of this test 

and Test No. 2 of Phase 4 described below, demonstrated that the 

modified impact limiter design prevents the neutron shield from 

contacting the impact surface. 

vi. Thirty-Foot Side Drop - Test No. 2 of Phase 4 

After rotating the limiter from the oblique drop test 180 degrees, 

the side drop was performed for Phase 4. In the slap down test, 

the loading is not uniform and tends to be concentrated towards 

the slap down end. In the side drop the loading tended to be 

uniformly distributed over the length of the cask and equally 

applied to each impact limiter. 

The high-speed film verified that the cask was horizontal as it 

approached the impact surface. For the side drop test, the crush 

stroke was 2.16 inches for the bottom impact limiter and 2.04 
- 23 - 

inches for the top impact limiter. The crush data does reflect that 

a clearance will exist between the neutron shield and the impact 

plane after the side drop condition. 

The maximum strain (135 in/in) and the maximum stresses (29.5 

ksi axial and 17.5 ksi hoop) occurred at the 180 degree location of 

the cask midpoint for the side drop. The side drop stresses were 

larger than those for the oblique drop even though the oblique 

drop deceleration was 10 percent larger. The accelerometers 

measured accelerations of 208 g on one end of the cask and 204 

g on the other end of the cask. This concurs with the crush stroke 

data. 

The pressure measured before and after the test remained 

constant to within the accuracy of the instrumentation, indicating 

that no loss of pressure occurred during the test. The metrology 

data indicate that, for a measurement tolerance of 0.01 inch, none 

of the diametral dimensions changed. During basket removal, the 

basket was removed without resistance and no deformations was 

identified. Performance of this test and Test No. 1 of Phase 4 

described above, demonstrated that the modified impact limiter 

design prevents the neutron shield from contacting the impact 

surface. 

2. Static Impact Limiter Test Information 

For the end impact case, the impact limiter compression forces from the 

quasi-static test are higher than the analytical values using the maximum 

tolerance cold temperature crush strength and the minimum tolerance hot 

temperature crush strength properties of redwood. This difference in 

compression forces can be attributed to the additional forces on the cask 

due to the redwood material's resistance to shearing along the periphery 

of the "backed" area of the cask. The calculated equivalent deceleration 

force of the full-scale cask, based on the quasi-static eighth-scale model 

impact limiter test, is 54.8 g for the end impact case. This force is greater 

than the analytically determined 44.6 g end drop deceleration force using 

the maximum tolerance cold temperature crush strength of redwood, but 

less than the analytically determined 56.1 g deceleration force obtained 

using the minimum tolerance hot temperature crush strength of redwood. 

The higher deceleration force obtained using the minimum tolerance hot 

temperature crush strength of redwood is a result of the larger 

deformation and the partial lock-up of the redwood that occurs before the 

cask is stopped. Based on the area under the dynamically scaled forcedeformation curve for the end impact case, all of the energy of a oneeighth scale model of the NAC-STC for a 30-foot drop is absorbed when 

the impact limiter deformation reaches 1.58 inches (1.63 inches from the 

static force-deformation curve), which extrapolates to a 12.6-inch 

deformation for the full-scale NAC-STC impact limiter, or 42 percent of 

the depth of the impact limiter. 
- 24 - 

For the corner impact case, the calculated equivalent deceleration force 

of the full-scale cask, based on the quasi-static eighth-scale model impact 

limiter test, is 32.6 g. This compares with the analytically determined 44.0 

g deceleration force using the maximum tolerance cold temperature crush 

strength of redwood, and with the analytically determined 49.3 g 

deceleration force calculated using the minimum tolerance hot 

temperature crush strength of redwood. Based on the area under the 

dynamically-scaled force-deformation curve presented for the corner 

impact case, all of the energy of a one-eighth scale model of the NACSTC for a 30-foot drop is absorbed when the impact limiter deformation 

reaches 3.22 inches (3.30 inches for the static force-deformation curve), 

which extrapolates to a 25.76-inch deformation for the full-scale NACSTC impact limiter, or 70 percent of the depth of the impact limiter. 

For the side impact case, the calculated equivalent deceleration force for 

the full-scale cask, based on the quasi-static eighth-scale model impact 

limiter test, is 45.6 g. This force compares with the analytically 

determined 51.7 g deceleration force using the maximum tolerance cold 

temperature crush strength of redwood and with the analytically 

determined 51.3 g deceleration force using the minimum tolerance hot 

temperature crush strength of redwood. Based on the area under the 

dynamically-scaled force-deformation curve presented for the side impact 

case, all of the energy of a one-eighth scale model of the NAC-STC for a 

30-foot drop is absorbed when the impact limiter deformation reaches 

1.64 inches (1.70 inches for the static force-deformation curve), which 

extrapolates to a 13.12-inch deformation for the full-scale NAC-STC 

impact limiter, or 71 percent of the depth of the impact limiter. 

The aluminum alloy shells split along the weld seams and came apart as 

compressive load was applied. The Type 304 stainless steel shells 

remained ductile and did not split along the weld seams. The eighthscale model impact limiter compression tests showed that a maximum of 

8.2 percent of the absorbed energy may be stored during crushing and 

later released. The results of the eighth-scale model NAC-STC impact 

limiter quasi-static compression tests clearly demonstrate that the NACSTC impact limiter design provides the energy absorption capacity to 

decelerate the cask to a stop for a 30-foot drop accident for the various 

impact orientations while maintaining maximum compression forces that 

are less than the cask design values. 

5. Model No. TN-FSV (Docket No. 71-9253) 

The information below was obtained from Section 2.10.3 in Public Service Company of 

Colorado’s SAR pages submitted with their response to a request for additional 

information by NRC staff (see ADAMS Accession No. ML063530662) for the impact 

limiter tests. 
- 25 - 

A. Tests performed 

A series of static and dynamic tests was performed on three half-scale models of 

the TN-FSV impact limiters. The following two static crush tests were performed 

on a single half scale TN-FSV impact limiter at room temperature: 

• Load applied radially on the side (0 degree) of the impact limiter, and 

• Load applied on the corner at an angle of 10 degree to simulate the 80 

degree corner drop. 

The 0 degree orientation was selected because it has the highest transverse g 

loading at the center of gravity. The 80 degree corner crush test was selected 

because it has high axial g loadings, and higher expected impact limiter 

deformations than the end drop. 

Two 30-foot drop tests were performed at low temperature to evaluate the 

adequacy of the impact limiter enclosure and attachments. The orientations 

were a 15 degree slap down (shallow angle side drop) and an 80 degree corner 

drop. The 15 degree slap down orientation was selected because it puts the 

highest stresses on the attachment bolts, and it is the orientation for which the 

highest impact force is expected for a side drop orientation. The 80 degree 

corner drop was selected to compare with the static test and because it is the 

orientation for which the largest limiter deformation is expected and for which 

significant decelerations are expected. 

All the kinetic energy of the model package must be absorbed by a single limiter 

for the 80 degree corner test which is very nearly a center of gravity over corner 

test. In a 0 degree side impact, 50% of the total energy must be absorbed by 

each of the two limiters. However, analyses indicated roughly 68% of the energy 

is absorbed by the secondary impact limiter (i.e., the impact limiter hitting 

second) for a shallow angle (slap down) side drop. Therefore, since the impact 

of the second impact limiter is nearly the same as a 0 degree side drop, the 0 

degree static crush test was continued to an energy level beyond 50% to 

approximate the second hit of the 15 degree side drop. 

B. Description of the methods or analyses used in tests 

For the static crush tests, the stainless steel impact limiter structure is steel shells 

closed off by flat plates and reinforced by six (6) radial gussets. The model and 

full-scale configurations are identical, but all linear dimensions in the model are 

half-scale. Although the balsa and redwood densities used in the model are 

consistent with that specified for fabrication of the full-scale impact limiters, the 

wood used in the models had densities on the high end of the specified range. 

The model contains the same number of wood blocks as the full-size impact 

limiters. The wood blocks are made up of a number of smaller pieces of wood 

glued together with phenol resorcinol adhesive, using the same procedure to be 

used on the full-size impact limiters. The attachment bolts are made from the 

material specified for the full-size limiters. Bolts (5/8-11-2A) with an undercut 

shank diameter of 0.511 in. were used on the models. 
- 26 - 

The testing was performed using a 1.2 x 106 lb. compression testing machine. 

The loading surface was maintained perpendicular to the direction of crushing 

and the massive impact limiter support fixture was restrained from shifting during 

loading. The deflection of the impact limiter was measured continuously during 

testing using a linear potentiometer mounted to the testing machine crosshead. 

The crush force versus vertical movement of the test plate was recorded 

continuously on an x-y plotter. 

For the dynamic tests, the test model is a solid carbon steel test body with a front 

impact limiter on each end. The test body is 103.5 inches long with an outside 

diameter of 15.5 inches. The total length of the dynamic test model, including 

impact limiters, is 123.5 inches. The dynamic tests were performed in 

accordance with approved written procedures. The impact surface was an 

unyielding concrete pad weighing more than 250,000 lbs. resting on bedrock. A 

mild steel plate, 2 inches thick, was secured to the surface of the concrete pad. 

The test drop height was 30 feet + 1.0 in./-0.0 in. Each drop was photographed 

and videotaped. 

For the slap down test, the impact limiter that impacts second was cooled more 

than 18 hours to a temperature of -20 °F prior to attachment to the test body. 

The ambient temperature was 9 °F during the drop test. Following the slap down 

test, the test model was rotated 180 degrees to allow the uncrushed side of the 

impact limiter used for the primary hit in the slap down case to be used for the 80 

degree corner drop. As before, the ambient temperature was around 9 °F. 

C. Test Results 

The side crush static test was terminated when the deflection reached 

approximately 5 inches and 81% of the kinetic energy associated with a 30-foot 

package drop was absorbed (5 of the 6 attachment bolts were simultaneously 

broken at this point). Significant deformation of the impact limiter was evident 

after the test. The bolt tunnels above the heads of the attachment bolts 

collapsed so that the heads of the bolts were inaccessible. The weld seams 

between the outer cylindrical shell and the flat plates on the front edge of the 

impact limiter tore approximately 3-4 inches in length in two places directly below 

the impact surface. Similarly a 3-inch tear on the back edge of the impact limiter 

was evident. After the impact limiter was removed from the fixture, evidence of 

inside crushing of the impact limiter was noticed. The seam between the inner 

cylindrical shell and circular plate had split in the region closest to the impact. 

After the slap down test, the impact limiter attachment bolts that hit first lost their 

torque due to deformation of the washers beneath the bolt heads as well as 

tightening of the impact limiter against the test body because of the drop. None 

of the bolts were broken. Two weld seams between the gussets and flat 

segments opened slightly. The primary impact limiter pushed inward toward the 

test body indicating inside crushing, and also crushed on the outside at a 

15 degree angle. The crushing on the secondary impact limiter was similar to a 

0 degree angle (perpendicular to the package axis) side drop crush. Therefore, 

dynamic test data from the secondary impact limiter is compared to load-versusdisplacement curves generated from the side crush static test data. Analyses 

indicated, for a 15 degree side drop, that roughly 68% of the total kinetic energy 
- 27 - 

associated with a 30-foot package drop is absorbed by the secondary impact 

limiter (rather than 50% for a true side drop). The permanent crush depth 

associated with the secondary impact limiter after the dynamic test was about 

3.57 inches not including elastic springback and about 3.82 inches assuming an 

estimated 0.25 inches of springback from static crush test data. The 

corresponding deflection from the associated load-versus-displacement curve is 

4.4 inches. The crush deformations, therefore, agree within about 14%. 

The corner crush static test was terminated after the deflection reached 7 inches 

and a total of 113% of the required energy was absorbed. The bolt tunnels 

above where the bolts are installed had buckled and folded closing the bolt holes. 

Although the outer cylinder bulged near the top seam, no exterior seams opened 

as a result of the corner crush test. After the 80 degree corner crush test, one 

segment of the impact limiter was cut open. The wood was removed and 

examined. It was noted that glue joints between the individual pieces of wood in 

the blocks did not fail as the wood crushed. For the corner crush static test, with 

100% of the kinetic energy associated with a 30-foot drop absorbed by the 

impact limiter, the measured deflection was 6.5 inches. 

After the corner crush dynamic test, the attachment bolts also lost their torque. 

There was evidence of both inside and outside crushing. The side of the impact 

limiter closest to the edge hitting first pushed around the test body due to inside 

crushing of the limiter on one side. Total deflection for the 80 degree corner 

drop, without accounting for springback, was calculated to be 6.3 inches and 

6.5 inches assuming an estimated 0.2 inches of springback from the static test 

data. 

6. Model No. NUHOMS® MP187 Multi-Purpose Cask (Docket No. 71-9255) 

The information below was obtained from Sections 2.10.11 and 2.10.12 in 

Transnuclear’s NUHOMS®-MP187 Multi-Purpose Cask SAR (see ADAMS Accession 

No. ML063520505) for the dynamic and static impact limiter tests, respectively. 

A. Tests performed 

1. Pre-operational Tests 

Prior to performing the certification test program a series of five preoperational drop tests were performed, using two quarter-scale models. 

The pre-operational drops conducted with these limiters were: 

• Test 1: 30 ft.-0 in. drop with package axis at 30 degrees to horizontal, 

impact onto small diagonal facet with slap down onto opposite limiter; 

• Test 2: 30 ft.-0 in. drop with package axis at 30 degrees to horizontal, 

impact onto large flat facet with slap down onto opposite limiter; 

• Test 3: 30 ft.-0 in. flat side drop with impact on large flat sides; 

• Test 4: 30 ft.-0 in. vertical drop; and 
- 28 - 

• Test 5: 30 ft.-0 in. flat side drop with impact onto diagonal corners of 

the limiters to impart the maximum rotational energy to the test article. 

2. Dynamic Impact Limiter Tests 

The dynamic tests were performed using two quarter-scale prototypical 

impact limiters, in multiple uses, in different drop orientations. The test 

sequence was as follows: 

• A 30-foot drop with the package longitudinal axis inclined at 30 

degrees to the horizontal and the 90 degrees azimuth at the top. 

Primary impact was on the large flat facet at 270 degrees azimuth on 

impact limiter "a" with a secondary impact (slap down) onto impact 

limiter "b". 

• A 30-foot drop with the package’s center of gravity over a corner and 

the package’s axis inclined at 72 degrees to the horizontal and rotated 

so that impact will occur on a diagonal corner of impact limiter "a." 

• A 40-inch drop onto a mild steel quarter-scale, cylindrical puncture 

spike. The spike had a diameter of 1.50 inches, a top edge radius of 

0.06 inches, and a projected length of 16.0 inches, or 28.0 inches 

above the surface of the drop pad. The package was oriented at 45 

degrees to the vertical on limiter "b." The 40 inch distance was 

measured from the point of impact on the package to the top of the 

puncture spike. 

• The end puncture event was performed on impact limiter "a" using a 

quarter-scale, cylindrical puncture spike similar to that described for 

the immediately above. 

3. Static Impact Limiter Test Information 

The static test program was developed using two quarter-scale model 

impact limiters for multiple tests in different loading orientations. The total 

crush deflections imposed for each test were larger than the maximum 

predicted deflection expected to occur under the bounding loading 

conditions. The static tests are numbered sequentially from test 5 to 9. 

Details of the test program, starting at Test Number 5 are: 

5. A static test with the load applied to the 45 degrees azimuth flat 

surface of the honeycomb portion of the limiter. 

6. A static test, on the same impact limiter, with the load applied to the 

180 degrees azimuth large flat honeycomb facet. 

7. With a new impact limiter, the static load was applied at 30 degrees 

to the package longitudinal axis to the 180 degrees azimuth large flat 

side of the limiter. 
- 29 - 

8. A static load was applied at 30 degrees to the package longitudinal 

axis through the 40 degrees azimuth small corner facet. 

9. A third static test was performed on the second impact limiter. For 

this test the load was applied at 60 degrees to the package 

longitudinal axis to the 325 degrees azimuth diagonal corner of the 

impact limiter. 

B. Description of the methods or analyses used in tests 

1. Pre-operational Tests 

The pre-operational drop tests were performed to demonstrate that the 

equipment and digital acquisition system were working correctly. The 

pre-operational test models were identical to the certification limiters with 

the exception of the honeycomb material. For the pre-operational tests 

the honeycomb was replaced with foam of similar density and crush 

strength; all other details were identical. 

2. Dynamic Impact Limiter Tests 

The primary method of determining package deformations was high 

speed film. High-speed cameras provided 400 and 2,000 frames per 

second coverage during all four dynamic tests. The cameras were placed 

parallel and perpendicular to the package impact zone to provide 

optimum viewing for measurement of the dynamic deformation in the 

impact limiters. Photometric coverage also included real-time color video 

and still shots. Painted backboards 12 ft. wide by 8 ft high, with a 12-inch 

lined grid, were placed behind the drop pad to provide a contrasting 

background to assist in measurement of the dynamic deformation of the 

limiters from the film. Following film processing the total impact limiter 

deformations were determined using a film comparitor with the capability 

of resolving displacements to 1/10th of an inch. 

As a backup to the film, eight accelerometers were mounted to the 

package to measure rigid body accelerations. The accelerometers were 

installed at the package center of gravity and at each end adjacent to the 

impact limiters, close to the location of the "critical" spacer discs for the 

full scale package. 

3. Static Impact Limiter Test Information 

The instrumentation used for these tests consisted of displacement and 

load transducers. The deflection of the specimen was measured with two 

wire potentiometers (wirepots), one on each side of the special loading 

plates installed under the universal testing machine head. The average 

of these two measurements was used to characterize the deflection 

corresponding to the applied load. Another displacement transducer was 

used to measure the deflection of the lower part of the impact limiter. In 

addition, the displacement of the universal testing machine head (stroke), 

measured via an internal transducer, was also recorded for data 
- 30 - 

verification purposes. The applied load was measured by a pressure 

transducer installed inside the control panel of the universal testing 

machine. All instruments were calibrated prior to the testing program. 

C. Test Results 

1. Pre-operational Tests 

Test 1: For the first test, the two impact limiters impacted at different 

times. The impact forces calculated for the first impact limiter were 57 g 

in the longitudinal direction and 187 g in the transverse direction. The 

impact forces measured for the first impact limiter were 66 g and 63 g in 

the longitudinal direction and 185 g and 90 g in the transverse direction. 

The impact forces calculated for the second impact limiter were 18 g in 

the longitudinal direction and 203 g in the transverse direction. The 

longitudinal direction impact forces measured for the second impact 

limiter were 29 g and 23 g. The transverse direction impact forces 

measured for the second impact limiter were 335 g and 225 g. These 

transverse direction impact forces, when adjusted by the dynamic load 

factor associated with the rigid body effect of the dummy package, which 

is discussed below, equal 210 g and 141 g. 

Test 2: For the CG-over-corner drop test, the calculated longitudinal and 

transverse forces were 110 g and 40 g respectively. The measured 

longitudinal forces were 110 g. while the measured transverse forces 

were 52 g and 30 g. 

Test 3: The 45 degrees drop puncture spike cleanly punched through the 

stainless steel impact limiter shell and foam until it impacted the 

reinforcing ring at the inner shell. The internal reinforcing ring deflected 

the pin to follow the inner cylindrical shell; no puncture of the inner shell 

occurred and the pin was stopped 1.5 inches short of the package 

attachment ring by a highly compacted wedge of honeycomb. The total 

penetration into the limiter was approximately 11.5 inches. With the 

vertical motion of the test article stopped by the limiter, the package 

toppled, and bent the pin through a 45 degrees angle without tearing any 

of the material from the limiter. After the opposite limiter contacted the 

ground, the test article rolled sideways and the pin was then bent 

approximately 90 degrees to the initial bend without any evidence of any 

material tearing from the limiter. Internal damage to the limiter was 

restricted to broken foam and crushed honeycomb material at the entry 

point. The maximum gap was 3 inches at the foam/honeycomb interface 

where the initial 45 degrees rotation of the pin occurred; there were no 

other damaged areas that have any impact on the integrity of the limiter. 

Test 4: The puncture pin penetrated 13.0 inches to the inner steel shell 

while being deflected sideways approximately 4 inches to impact on the 

reinforcing ring at the outer edge of the inner shell. The slow-motion film 

showed that the test article stopped with the pin completely embedded in 

the limiter and then slowly toppled, bending the puncture pin at 

approximately 60 degrees. After the test article rotated about 60 degrees, 
- 31 - 

the bottom edge of the impaled limiter contacted the test stand, the 

impact point on the bottom of the limiter was raised vertically, and the pin 

pulled up and out of the stand. Damage to the limiter was confined to the 

puncture entry point and the slightly curved path taken to the impact point 

on the inner shell. The stainless steel outer shell and foam had sufficient 

strength to totally restrain the pin and bend it through 60 degrees, plus 

extract it from the test stand. 

Dummy Package Tests: Examination of both the pre-operational and 

certification acceleration test data showed a ringing signature at 

approximately 350 Hz for the flat side slap down drop. This response 

indicated that the test results included a significant non-rigid body 

response. Two additional drops of the dummy package without impact 

limiters were conducted to determine the natural response of the bare 

package. The package was instrumented the same as the certification 

tests and dropped from heights of 12 and 40 inches. These drops both 

measured a natural frequency at the same frequency as the ringing tone 

(approximately 350 Hz). Additional analyses were conducted to include 

the response of the dummy package and define the rigid body response. 

A dynamic load factor was determined for a range of frequencies for a 

damping ratio of 6%. The damping ratio was calculated as the 

logarithmic decrement from the filtered drop acceleration time histories. 

The predicted rigid body response for the flat side slap down drop was 

used as the forcing function for the dynamic load factor calculation. This 

analysis produced a predicted dynamic load factor of 1.6. Applying the 

calculated dynamic load factor of 1.6 to the measured peak accelerations 

produced the rigid body response. 

The pre-operational tests clearly demonstrated that the impact limiter 

attachment bolts, and package attachments, were robust and capable of 

sustaining the design basis drop loads and keep the limiters securely 

attached to the package for multiple design basis drops. 

2. Dynamic Impact Limiter Tests 

Test 5: The limit event for this test was a deflection of 5.5 inches. The 

specimen was loaded to a peak load of 287 kips, which produced a 

deflection of 5.61 inches. The deflection after removing the load was 

4.69 inches. 

Test 6: Test 6 occurred immediately following test 5. The limit event was 

defined to be a deflection of 5 inches. Loading was interrupted when the 

deflection was 3.86 inches (386 kips of load) because the loading fixture 

was too close to the test fixture. The displacement instrumentation was 

disconnected, and the position of the loading fixture under the universal 

testing machine head was moved to apply further deformation to the 

specimen. The displacement transducers were reconnected to the 

specimen, and the load reapplied. 
- 32 - 

Testing was stopped when the load was 603 kips and the displacement 

4.81 inches because the loading fixture was again close to the test fixture. 

Local buckling and yielding were also observed in the test fixture beams 

supporting the triangular component of the test fixture. The localized 

failure of the test fixture permitted a small rotation of the test fixture and 

imparted a small deflection component to the measured results. As the 

honeycomb material had been crushed to a solid matrix, this deflection is 

not considered to be important. The local buckling failure of the test 

fixture is not loaded in subsequent tests and did not require repair before 

continuing the loading sequence. After removing the load, the permanent 

deflection of the specimen was (60% crush) 3.81 inches. 

Test 7: The defined limit displacement was 4 inches. Loading was 

stopped when the deflection was 3.85 inches because the loading plate 

was too close to the test fixture. The maximum load applied to the 

specimen of 484 kips occurred at a displacement of 3.52 inches. A 

permanent deflection of 2.79 inches was measured after unloading the 

specimen. The wire of the potentiometer used to measure bottom 

displacement snapped at a displacement of 1 inch and 322 kips of load. 

Test 8: The specimen was loaded to 339 kips, with a corresponding 

displacement of 5.67 inches. Following a visual examination of the 

impact limiter, it was decided to apply further loading. The peak load 

measured during the test was 373 kips with a corresponding deflection of 

6.25 inches. The peak displacement measured was 6.44 inches, after the 

load had dropped to 353 kips. The permanent deflection after unloading 

was 5.15 inches. 

Test 9: The limit event was a displacement of 9.6 inches. This 

displacement was achieved with a load of 484 kips. It was then decided 

to load the specimen further. The peak load achieved was 700 kips at a 

deflection of 10.74 inches. The peak deflection was 10.90 inches, 

measured after the test was paused, and the load had dropped to 648 

kips. The permanent deflection after unloading was 9.06 inches. 

7. Model No. HI-STAR 100 System (Docket No. 71-9261) 

The information below was obtained from Appendix 2.A of the SAR for the HI-STAR 100 

Cask System, Revision 15, dated October 11, 2010 (see ADAMS Accession No. 

ML102871079). 

A. Tests performed 

A series of static compression tests were performed on eighth-scale models of 

the impact limiter for the HI-STAR 100 package. These crush tests were 

performed to document the force-deflection and energy absorption 

characteristics of the honeycomb material used in the impact limiter. The tests 

were conducted at temperatures ranging from -30 °F to 120 °F with impact limiter 

orientations of 0 degrees (side), 30 and 60 degrees (oblique) and 90 degrees 

(end). The purpose of this test was to confirm the static force-crush prediction 
- 33 - 

model, determine the effect of temperature on the impact limiter and access and 

confirm the performance of the impact limiter backbone. 

A series of free drop tests were performed on quarter-scale models of the 

HI-STAR 100 package instrumented with five accelerometers. Thirty-foot drop 

test orientations included a vertical top end drop, top corner drop at an angle of 

67.5 degrees from horizontal (center of gravity over corner), side drop, and a 

slap-down drop at an angle of 15 degrees from horizontal so that the top impact 

limiter hits the surface first followed by a higher velocity impact of the bottom 

impact limiter. 

The purpose of these tests were to confirm the predictions of the finite element 

software LS-DYNA used to create a full scale model of the HI-STAR 100 

package and the AL-STAR impact limiter, specifically, the deceleration of the 

package, impact duration, maximum crush depth of the impact limiter and 

performance of the attachment system. Following the confirmation of the model, 

three more drop tests were performed at 30, 45 and 60 degrees with content 

weight varying from 270,000 lbs. to 280,000 lbs. (range of weight allowed in the 

package) to confirm the impact orientation of maximum damage. 

B. Description of the methods or analyses used in the drop tests 

The package was instrumented with five accelerometers to determine maximum 

deceleration of the package and record the duration of the impact for the scale 

model. Three accelerometers were attached at three axial locations. The other 

two accelerometers were attached 120 degrees from the first three, and aligned 

with the top and bottom accelerometer. 

C. Test Results 

Data obtained from the tests consists of both qualitative information with respect 

to observations about the package and the limiter and quantitative data obtained 

from the recorders. The data for each test include measured impact limiter 

deformation, deceleration time history, and observations of the package and 

attachments. 

1. Impact Limiter Force-Deflection Tests 

The static compressions tests were performed on eighth-scale model 

impact limiters used in drop testing the quarter-scale model. Of the four 

compression testes performed, two (0 and 30 degrees) were 

unsatisfactory, because the backbone did not remain elastic. The other 

two orientations (60 and 90 degrees) showed close agreement of the 

numerical model. As a result, the backbone was redesigned, and three 

additional eighth-scale model tests were performed at 0 degrees (side), 

67.5 degrees (center of gravity over corner) and 90 degrees (top end). 

The backbone remained elastic and the force-deflection results showed 

close agreement with those predicted by the numerical model. 

Additionally, the tests indicated that temperature (within the range tested 

and the regulatory requirements) has no effect on the performance of the 

impact limiter. 
- 34 - 

Following the quarter-scale model testing, three additional compression 

tests were performed on three eighth-scale models of the impact limiter. 

The orientations were 0 degrees (side) 67.5 degrees (center of gravity 

over corner) and 90 degrees (top end). Good agreement was observed 

between the theory and the test for the side and center of gravity over 

corner crush orientations. For the end drop, the test results suggested 

that there may be elastic behavior at the interface of the package and the 

impact limiter that the model was not capturing. The dynamic test results 

(described below) demonstrated that the predication of the peak 

deceleration, extent of crush and impact duration were not affected by 

these elastic behavior effects. 

2. First Series of Drop Tests 

The orientations used for the first series of drop tests included the top 

end, center of gravity over corner and the side drop. The peak 

deceleration of the top end drop was well above the design basis of 60g. 

The reasons for the discrepancy between the test and the model were 

determined to be the use of a low value for a dynamic multiplier assumed 

in the impact limiter design and the lack of pre-crush of the honeycomb 

material in the impact limiter. As a result, the impact limiter was revised 

with new crush strengths and redesigned and a new set of quarter-scale 

model impact limiters was manufactured. 

3. Second Series of Drop Tests 

The same orientations were used in the first phase of the second series 

of drop tests. In all cases, the deceleration values were within the design 

limit of 60g; however, the attachment system did not survive the side 

impact drop test. The attachment system was redesigned prior to the 

slap-down test, which is considered to be the most definitive test of the 

package/impact limiter attachment integrity. The bottom impact limiter 

remained in place following the slap-down test and the deceleration was 

within the design basis. 

Table 2.A.3 and 2.A.4 of the SAR shows the comparison of the test date 

for the seven drop tests with the prediction of the LS-DYNA software 

model. The predicted deceleration values, impact duration and total 

crush depth compared well with the test data. In three cases, the test 

data exceeded the predicted value of the model. In these cases, the 

measured total crush depth was greater than the predicted crush depth, 

but in all cases, the actual total crush depth was less than 80% of the 

available depth. This means there was several inches of impact limiter 

available to crush before package would impact the surface. 

The results of the compression tests and the drop tests confirmed the 

accuracy of the numerical model, which was used to simulate the onefoot drop required for the assessment of normal conditions of transport. 
- 35 - 

The simulation produced maximum decelerations less than the design 

basis. 

8. Model No. UMS Universal Transport Cask Package (Docket No. 71-9270) 

The information below was obtained from Section 2.10.3 of the SAR on the Model No. 

UMS Universal Transport Package (UMS), Revision 99A, dated June 1999 (see ADAMS 

Accession No. ML063480388). 

A. Tests performed 

A series of free drop tests were performed on a quarter-scale model of the UMS 

package. Thirty-foot drop test orientations included a vertical top end drop, 

center of gravity over top corner drop, and a side drop. The test data consisted 

of measurements of the deformations of the impact limiter, the package 

accelerations, and inspection of the retaining rods. 

Two static crush tests were performed on quarter-scale models of the impact 

limiter for the UMS package. These crush tests were performed to confirm the 

design of the UMS impact limiters, specifically to identify any potential initial 

stiffness in the impact limiter and to indicate any effect of the thick walled screw 

tubes on the impact limiter crush force in the top end drop orientation. 

Additionally, the crush data were used to confirm the validity of the RBCUBED 

computer program analysis of the UMS impact limiter. 

B. Description of the methods or analyses used in tests 

The package was instrumented with 3 accelerometers for the top end drop and 

the top corner drop and 4 accelerometers for the side drop to determine the 

maximum deceleration and impact duration of each drop. Additionally, two highspeed cameras were used to record the behavior of the model as it impacted the 

target surface. 

C. Test Results 

Data obtained from the tests consist of both qualitative information with respect 

to observations about the package and the limiter and quantitative data obtained 

from the recorders. The data for each test include measured impact limiter 

deformation, acceleration time history and assessment of the angle of drop 

based on the high-speed camera. 

1. Top End Drop 

For the top end drop the impact limiter was sawn into quarters and the 

average crush was measured at 2.04 inches, which scaled up to 8.16 

inches for a full scale package. During the removal of the impact limiter, 

which required two hydraulic jacks, it was observed that several of the 

retaining fords had broken due to plastic buckling. Based on the 

accelerometer time history, the maximum deceleration was measured at 

51.8g and the impact duration was 12 milliseconds. The measured 

acceleration was bounded by the design basis value of 60g and the crush 
- 36 - 

depth was less than that required for the package to impact the impact 

surface. 

2. Static Crush Test for the End Drop Orientation 

To further confirm the design of the UMS impact Limiters, two static crush 

tests in a top end drop orientation were conducted to identify any potential 

initial stiffness in the impact limiter and to indicate any effect of the thick 

walled screw tubes on the impact limiter crush force. The results of the 

static crush test confirmed the response of the impact limiter in the top 

end drop impact, and confirmed the validity of the RBCUBED program 

analysis 

3. Side Drop 

Following the side drop, it was observed that the three retaining rods 

nearest the impact had broken, but that the remaining 13 of 16 retaining 

rods were intact and still threaded into the model body. The scaled-up 

crush depth was 11.8 inches and 11.4 inches for the top and bottom 

impact limiters respectively, which compared well with and were bounded 

by the RBCUBED predicted values of 13.0 and 13.7 inches. 

The peak accelerations for the top and bottom impact limiters were 51.1g 

and 37.9g respectively, which were also bounded by the RBCUBED 

predicted values of 52.1g and 48.6g. The measured accelerations were 

all bounded by the design basis value of 60g and the crush depth was 

less than that required for the package to impact the impact surface. 

4. Center of Gravity over Top Corner Drop 

Like the side drop test, following the center of gravity over top corner 

drop, it was also observed that the three retaining rods nearest the impact 

had broken, but that the remaining 13 of 16 retaining rods were intact and 

still threaded into the model body. The scaled-up crush depth, 

12.8 inches, was significantly less than the RBCUBED predicted value of 

27.7 inches. The RBCUBED value bounded the actual crush depth. The 

acceleration time history from the accelerometers produced a maximum 

deceleration of 30g that was also significantly less than the RBCUBED 

predicted value of 47.8g, both of which are less than the design basis of 

60g. 

The test confirmed that the UMS impact limiters are able to provide an 

adequate design margin to limit the deceleration and the crush depth of 

the transport package for drop test. 

9. Model No. FuelSolutionsTM TS125 Transportation Package (Docket No. 71-9276) 

The information below was obtained from revision 6 of the FuelSolutionsTM SAR dated 

September 2006 (see ADAMS Accession No. ML070230678). 
- 37 - 

A. Tests performed 

 

1. Development Testing 

A series of specimen bench tests and sub-model tests was performed to 

support the development of the impact limiter design. Specimen bench 

tests were performed to determine the characteristic behavior of the 

individual energy absorbing aluminum honeycomb materials used to 

fabricate the impact limiter. The aluminum honeycomb specimen tests 

examined the effects of crush rate, temperature, and impact orientation 

on the crush properties of the aluminum honeycomb materials. In 

addition, sub-model specimen bench tests were performed to address 

specific impact limiter design and loading issues. 

Quasi-static crush tests of aluminum honeycomb material having nominal 

crush strengths of 1,200 psi and 2,500 psi were performed for a range of 

crush orientations and temperatures. Quasi-static crush tests were 

conducted along each of the principal axes for both 1,200 psi and 2,500 

psi material at room temperature. Additional quasi-static crush tests were 

performed at temperatures of –20 °F and 220 °F. Three separate 

specimens were tested for each condition. 

2. Confirmatory Static Crush Testing 

Quasi-static crush tests, using scaled impact limiter test articles, were 

performed to confirm the adequacy of the inputs used in the analytical 

tools and methodology used to calculate the impact limiter forcedeflection relationships. These tests address the effects of impact limiter 

geometry and construction and the effects of backing on the forcedisplacement relationship for various impact orientations. In addition, the 

quasi-static crush tests confirm the adequacy of the attachments used to 

secure the impact limiters to the transportation package. The orientations 

for the quasi-static crush tests include the end, center of gravity over 

corner, and side crush orientations. All static crush tests were performed 

using either an eight-scale or quarter-scale replicas of the full-scale 

impact limiter design. 

3. Confirmatory Drop Testing 

The 9-meter (30-foot) free drop tests were performed using quarter-scale 

impact limiter test articles to confirm the adequacy of the analytical tools 

and methodology used to calculate the rigid-body response of the 

transportation package for the free drop conditions specified in Title 10 of 

the Code of Federal Regulations (10 CFR) Part 71. The dynamic drop 

tests address the dynamic response of the impact limiter energyabsorbing materials for various impact orientations. In addition, the 

dynamic drop tests confirm the structural adequacy of the impact limiter 

shell assembly and the hardware used to attach the impact limiter to the 

ends of the transportation package. Four free drop orientations have 

been tested, including: 
- 38 - 

• End Drop – A free drop with the package longitudinal axis orientated 

perpendicular to the target (i.e., vertical). 

• Corner Drop – A free drop with the package longitudinal axis oriented 

at an angle of 21 degrees with respect to vertical. This orientation 

places the package center of gravity directly over the center of the 

crush force. 

• Side Drop – A free drop with the package longitudinal axis oriented 

parallel to the target (i.e., horizontal). 

• Slapdown – A free drop with the package longitudinal axis initially 

oriented at an angle of 75 degrees from vertical (i.e., 15 degrees from 

horizontal). This free drop condition results in a primary impact and 

as subsequent secondary impact (i.e., slapdown). 

B. Description of the methods or analyses used in tests 

1. Development Testing 

The tests were performed using blocks having a 4.00-inch by 4.00-inch 

cross-section and a thickness of 2.00 inches in the direction of crushing. 

Pre-crushed test specimens were used for the static crush tests. The 

pre-crushed specimens were created by cutting the blocks 2.25 inches 

thick, and crushing one side 0.25 inch to attain the final 2.00-inch 

thickness. Each specimen had 0.020-inch thick 5052 aluminum alloy 

sheets bonded to each of the 4.00-inch x 4.00-inch faces to help reduce 

the possibility of sample splitting during the test. This resulted in a 

nominal specimen thickness of 2.04 inches. All quasi-static crush tests 

were conducted using a head speed of 0.2 inch per minute. 

2. Confirmatory Static Crush Testing 

The eighth-scale end crush test was performed on a 300-ton capacity 

manual static testing machine at an approximate head speed of 0.2 inch 

per minute unless noted otherwise. The force measurements were 

manually recorded from the dial gauge on the Tinius-Olsen machine, and 

the displacements were manually recorded from a patriot gauge with a 

digital displacement indicator. 

3. Confirmatory Dynamic Drop Testing 

Data collection and reduction was performed by Sandia National 

Laboratories using the Mobile Instrumentation Data Acquisition System. 

The 44-foot long MIDAS trailer, which was developed by Sandia National 

Laboratories using the Mobile Instrumentation Data Acquisition System 

for the U.S. Department of Energy to provide efficient and accurate test 

data acquisition and analysis for radioactive material packages, was 

located at the drop test site. 
- 39 - 

The test assembly was instrumented with a total of 18 accelerometers 

attached at various locations on the outer surface of the test fixture, 

providing sufficient redundancy. The accelerometers used provide 

accurate measurement of response frequencies up to 20 kHz and 

accelerations exceeding 1,000g. 

C. Test results 

1. Development Testing 

The results of the quasi-static crush tests are summarized in the table 

below. The average crush strengths shown represent an average over 

the flat response section of the stress-strain curves (i.e., neglecting initial 

rise and densification). The test results show that the average crush 

strength for 1,200 psi and 2,500 psi material at –20 °F is approximately 

7.5% higher than the average crush strength at room temperature. The 

test results also show that the average crush strength for 1,200 psi and 

2,500 psi material at 220 °F is approximately 11% lower than the average 

crush strength at room temperature. As discussed in the Hexcel CROSSCORE® product literature, the crush strength is generally 7% to 10% 

higher at –20 °F and 9% to 11% lower at 220 °F than the crush strength 

at room temperature. Therefore, the results of the static specimen crush 

tests confirm the information contained in the product literature. 

Core Type 

(Designation 

Number)

Nominal 

Crush 

Strength 

(psi)

Test 

Temp 

(°F)

Test 

Direction

Average 

Crush 

Strength 

(psi)

Average 

Densification 

Strain (%)

Average 

Densification 

Modulus 

(ksi)

AL-CC-3/16-

052-18.0 

(A8A00) 

1200 

-20 T1 1324 65.9 23.6 

70 T1 1239 65.8 26.1 

70 T2 1180 66.4 21.9 

70 W 179 NA NA 

220 T1 1106 67.8 25.6 

AL-CC-1/8-

5052-27.0 

(A8A06) 

2500 

-20 T1 2677 59.1 31.6 

70 T1 2417 60.6 20.5 

70 T2 2297 60.0 25.3 

70 W 814 NA NA 

220 T1 2169 61.8 28.1 

2. Confirmatory Static Crush Testing 

i. Quasi-Static End Crush Test Results 

The maximum crush depth (crosshead displacement) achieved in 

the eighth-scale quasi-static end crush test was over 5 inches, 

which is equivalent to a full-scale displacement exceeding 

40 inches. This crush depth conservatively exceeds the 14 to 

15 inches of crush (approximately 1.8 inches for eighth-scale) 
- 40 - 

required to absorb all of the kinetic energy for the worst-case hot 

end drop condition. Thus, the available stroke exceeds that 

needed to assure that bottoming out under the worst-case 

conditions does not occur. 

The resulting end crush force-deflection curve shows excellent 

agreement with the calculated static end crush force deflection 

curve. The general magnitude and slope of the test curve and 

calculated curve for the end crush test are within the expected 

experimental accuracy over the full range of interest. The only 

difference observed between the test results and the calculation is 

the initial response of the impact limiter. The test results show a 

gradual ramp-up over the first 0.2 inch of crush, whereas the 

calculated response shows an instantaneous rise. The difference 

results from the calculation assumption of fully effective backing 

through the entire crush range, which neglects initial shifting of the 

honeycomb segments within the impact limiter shell assembly. 

However, the ramped-up response for the end drop orientation is 

accounted for by adding a take-up deflection to the calculated 

acceleration time-history curves for the quarter-scale confirmatory 

end drop test and the full-scale drop load analysis, although this 

effect is not significant on the resulting loads. Therefore, it is 

concluded that the analytical tools, assumptions, and inputs used 

to develop the static force-deflection curve for the end crush are 

adequate. The resulting end crush force-deflection curve shows 

excellent agreement with the calculated static end crush force 

deflection curve. 

ii. Quasi-Static Corner Crush Test Results 

The crush depth achieved in the corner crush test was 

approximately 6 inches, which bounds the anticipated stroke 

required of the design. The calculated corner crush forcedeflection curve was determined using the dimensions and crush 

strengths of the eighth-scale impact limiter, with the same 

analytical tools and assumptions applied to the full-scale impact 

limiter corner drop loads evaluation. The calculated forcedeflection curve neglects the contribution of the impact limiter shell 

assembly, and assumes that all material is effectively backed and 

contributes to the crush force. The resulting corner crush forcedeflection curve shows excellent agreement with the calculated 

static corner crush force deflection curve. The general magnitude 

and slope of the test curve and calculated curve for the corner 

crush test are within the expected experimental accuracy over the 

full range of interest. Therefore, it is concluded that the analytical 

tools, assumptions, and inputs used to develop the static forcedeflection curve for the corner crush are adequate. The resulting 

corner crush force-deflection curve shows excellent agreement 

with the calculated static corner crush force deflection curve. 

iii. Quasi-Static Side Crush Test Results 
- 41 - 

A 600-kip capacity Tinius Olson hydraulic quasi-static testing 

machine with a 12-inch stroke and 1.2-inch per second maximum 

displacement rate was used for the test. The static side crush 

results show that the measured force-deflection curve exceeds the 

pre-test prediction force-deflection curve for deflections of 

approximately 2.2 inches and higher. Based on the results of the 

post-test evaluation using the modified input parameters, it is 

concluded that the analytical tools, inputs, and modified input 

parameters accurately predict the static force-deflection response 

for the static side crush condition. 

3. Confirmatory Dynamic Drop Testing 

i. 30-Foot End Drop Testing and Results 

The post-test measurements of the impact limiter show that the 

average crush distance resulting from the end drop is 3.5 inches, 

compared with the pre-test prediction of 3.2 inches. Upon posttest inspection following the end drop test, there was no 

noticeable failure of the impact limiter shell or the impact limiter 

attachment hardware. Therefore, the results of the 30-foot end 

drop test confirm the analytical tools, inputs, and assumptions 

used to determine the rigid-body response of the transportation 

package for the HAC end drop. 

ii. 30-Foot Side Drop Testing and Results 

The post-test measurements of the impact limiters showed that 

the maximum crush depth resulting from the confirmatory side 

drop test was 3.3 inches, compared to a pre-test prediction of 3.2 

inches. In general, the test results show excellent agreement with 

the pre-test prediction. 

Iii 30-Foot Corner Drop Testing and Results 

In general, the test results show excellent agreement with the pretest predictions. The measured test result exhibits the same 

general shape, pulse duration, and peak acceleration magnitude 

as the pre-test prediction. The post-test measurements of the 

impact limiter show that the crush distance resulting from the 

corner drop was approximately 6.4 to 6.8 inches, compared with 

the pre-test prediction range of 6.8 to 7.3 inches. Upon post-test 

inspection following the corner drop test, there was no noticeable 

failure of the impact limiter shell or the impact limiter attachment 

hardware. Therefore, the results of the 30-foot corner drop test 

confirm the analytical tools, inputs, and assumptions used to 

determine the rigid-body response of the transportation package 

for the hypothetical accident conditions corner drop. 

iv. 30-Foot Slapdown Drop Testing and Results 
- 42 - 

In general, the test results show excellent agreement with the pretest prediction for the primary impact and are slightly higher than 

the test prediction for the slapdown impact. The post-test 

measurements of the impact limiter show that the crush distance 

resulting from the slapdown drop primary impact is 2.9 inches, 

compared with the pre-test prediction of 4.6 inches. Similarly, the 

measured crush depth in the secondary impact limiter is 

approximately 3.0 inches, compared with the pre-test prediction of 

3.6 inches. Upon post-test inspection following the slapdown drop 

test, there was no noticeable failure of the impact limiter shell. 

During the test, two of the twelve attachment studs located on the 

crushed side of the impact limiter on the secondary impact end 

failed. However, the impact limiter remained attached to the test 

fixture throughout the duration of the test and all other attachment 

studs remained intact. Thus, the impact limiter attachment studs 

performed their intended function during the quarter-scale 

slapdown drop test. 

10. Model No. TN-68 Transport Package (Docket No. 71-9293) 

The information below was obtained from Section 2.10.9 in Transnuclear Inc.’s 

application, dated May 19, 1999 (see ADAMS Accession Nos. ML063340727 and 

ML063340703).

A. Tests performed 

A series of dynamic tests were performed on one-third scale models of the TN-68 

impact limiters. The tests were performed to evaluate the effect of the 30-foot 

free drop hypothetical accident defined 10 CFR 71.73(c)(1). The objectives of 

the test program were to: 

• Demonstrate that the inertia G values and forces calculated for the TN-68 

package and basket are acceptable. 

 Verify the adequacy of the impact limiter tie rods and bolts. 

 Demonstrate the adequacy of the impact limiter enclosure. 

The drop configurations examined are the 15o slap down, 90o end drop, 0o side 

drop, and 90o end drop for puncture. 

 B. Description of the methods or analyses used in tests 

Accelerometers (12 possible in total) were mounted to brackets around the 

exterior of the test body at 0o, 90o, 180o, and 270o orientations at the approximate 

center of gravity location and adjacent to each impact limiter. An inclinometer will 

be placed on the test body to measure the initial angle (± 1) of its longitudinal 

axis with respect to the target (i.e., impact surface). Data were collected by 
- 43 - 

accelerometers capable of measuring data at a minimum frequency response of 

6,000 Hz per channel. 

 C. Results 

The results of the 15o slap down showed that the adequacy of the attachment 

design of the impact limiters, and that the impact limiters did not bottom out and 

the trunnions would not impact the target. The 90o end drop resulted in both 

impact limiters remaining intact and crush values comparing well to predicted 

values. The 0o side drop indicated good correlation between measured and 

predicted crush depths for the side drop event. 90o end drop for puncture 

resulted in impact limiters staying attached to the package. In all, measured and 

predicted performance agreed very well. 

11. Model No. NUHOMS®-MP197, NUHOMS®-MP197HB (Docket No. 71-9302) 

The information below was obtained from Section 2.10.9, in Transnuclear Inc.’s 

application, dated May 2, 2001, pre-application meeting slides, and Appendix A.2.13.8.1 

(see ADAMS Accession Nos. ML063190444, ML090420165, and ML112640444). 

A. Tests performed 

One-third-scale tests were performed for the MP197 package to evaluate the 

effect of the 9 m free drop hypothetical accident defined in 10 CFR 71.73(c)(1). 

The unyielding drop surface consisted of a 2-inch thick steel plate secured to the 

surface of a concrete pad. The test model was a solid steel third-scale mockup 

of the package body with impact limiter. The steel body was designed to scale 

the weight and the center of gravity of the package. 

For the MP197 package, the objectives of the package impact limiter tests were 

to: 

• demonstrate that the inertia g values and forces used in the analyses are 

conservative, 

• demonstrate that the extent of the crush depths are acceptable (i.e., the 

neutron shield does not impact the target), and 

• demonstrate the adequacy of the impact limiter enclosures. 

The tests performed consisted of the following: 

• A 0° side drop because this orientation generates the highest transverse 

acceleration as well as significant deformation. The 0° side drop also 

provides a reasonable estimate of the likelihood of the neutron shield 

impacting the target. 

• A 20° slap down drop because the 20° orientation puts the highest load on 

the impact limiter attachment bolts, and stainless steel shell. 

• The 90° end drop orientation was chosen because it causes the highest axial 

deceleration. 

• The 40-inch drop onto a 1/3 scale 6-inch diameter puncture bar was 

performed in accordance with 10 CFR 71.73(c)(3). 
- 44 - 

Test Number Drop 

Orientation Drop Height 

Impact 

Limiter 

Number 

Location of impact 

limiter 

1 0° side drop 30 ft 1 

2 

Top 

Bottom 

2 20° slap down 30 ft 3 

2 

Top, 2nd impact 

Bottom, 1st impact 

3 90° end drop 30 ft 3 

4 

Top 

Bottom-impact end 

4 90° end drop 40 in 3 

4 

Top 

Bottom- puncture 

end 

B. Description of the methods or analyses used in tests 

An inclinometer was placed on the test body to measure the initial angle (±1°) of 

its axis with respect to the drop pad (impact surface). The impact surface was an 

unyielding horizontal surface, weighing more than 250,000 lb. versus 9,750 lb. for 

the weight of the 1/3 scale dummy. 

Accelerometers were used to measure the inertial g load during impact for the 

three 30-foot drops performed. At least 10 accelerometers were used during 

each 30-foot drop. 

Four, third-scale impact limiters were constructed for the drop testing. 

The following data were measured and recorded before, during and after each 

drop test: 

1. Prior to each drop test 

• Torque of the impact limiter bolts, 

• Impact limiter dimensions, 

• Height from test article to drop pad, 

• Angular orientation of the test article to the impact surface, and 

• Atmospheric condition data (i.e., ambient temperature, wind speed, 

immediately and prior to the release of the test article). 

2. During each drop test 

• Test article behavior on videotape, 

• Date and time of test, 

• Observations of damage or unexpected behavior of the test article, 

and 

• Impact acceleration time histories and frequency responses 

(excluding the puncture drop test). 

3. Following each drop test: 
- 45 - 

• Observations of the damage to the test article on features other than 

the limiters (i.e., attachment bolts). 

• Measurements of deformation to each impact limiter to fully describe 

the extent of the damage, including: 

o Depth of internal and external crush of the impact limiter 

o Overall thickness of each impact limiter after each test. 

o Dimensions of impact footprint 

C. Test Results 

The four drop tests were performed without any unusual observations. The 

impact limiters contained the wood during the drop tests, and none of the 

attachment bolts failed. 

No openings in the stainless steel impact limiter shell were evident and no welds 

in the shell failed. 

The puncture bar sheared a circular section of the outer shell of the bottom 

impact limiter. No other sections of the impact limiter were damaged and no 

welds on the impact limiter shell were broken. The puncture bar did not 

penetrate the inner stainless steel shell of the impact limiter or the aluminum 

thermal shield. Both impact limiters remained attached to the package during the 

puncture drop event and no additional impact limiter attachment bolts were 

damaged. 

The predicted performance of the impact limiters in terms of decelerations and 

crush depths agrees well with the measured data. 
- 46 - 

Results of the Third-scale benchmark LS-DYNA drop test vs. analysis 

Calculated decelerations (maximum value and time duration) are close to or 

bound the measured drop test decelerations. It is therefore concluded that the 

methodology, material models, and material properties are properly 

benchmarked. 

The results of the tests demonstrate that: 

• The crush depths do not result in lockup of the wood in the impact limiters, 

• The crush depths for the 0° side drop case would not result in the neutron 

shield impacting the target, 

• The predicted performance of the impact limiters in terms of decelerations 

and crush depths agrees well with the measured data, 

• The impact limiter enclosure is structurally adequate in that it successfully 

confines the wood inside the steel shell, 

Test Conditions Parameter Drop Test Results 

LS-DYNA 

Analysis

Results 

90o End 

Drop (-

20 oF) 

Acceleration 65g 65.1g 

Impact Duration 0.010 sec. 0.012 sec. 

Wood Crush Depth 2.5” 2.8” 

0° Side Drop

(Room 

Temperature) 

Acceleration 61g 65.6g 

Impact Duration 0.012 sec. 0.013 sec. 

Wood Crush Depth 2.69”-2.75” 2.7”-2.9” 

20° Slap 

Down 1st 

Impact 

(Room Temperature) 

Acceleration at Center of 

Package 17g 20.8g 

Acceleration at Bottom of 

Package 36g 40.1g 

Impact Duration 0.016 sec. 0.018 sec. 

Wood Crush Depth Bottom 

Limiter 4.92” 4.9” 

20° Slap 

Down 2nd 

Impact 

(Room Temperature) 

Acceleration at Center of 

Package 32g 36.3g 

Acceleration at Top of 

Package 73g 72.2g 

Impact Duration 0.009 sec. 0.010 sec. 

Wood Crush Depth Upper 

Limiter 4.72” 2.8” 
- 47 - 

• The impact limiter attachment design is structurally adequate in that the 

attachment bolts hold the impact limiters on the ends of the package during 

all drop orientations, and 

• The effects of low temperature (-20 °F) on the crush strength of the impact 

limiters is minor, and is bounded by the conservative accelerations and forces 

used in the analysis. 

A 40-inch drop onto a scaled 6-inch diameter puncture bar, as per 10 CFR 

71.73(c)(3), does not significantly destroy the impact limiter. The impact limiter 

and attachment remain firmly secured to the package and the impact limiter 

wood is confined. 

12. Model No. TN-40 (Docket No. 71-9313) 

The information below was obtained from Section 2.10.9 in AREVA’s application dated 

August 31, 2006 (see ADAMS Accession No. ML070750136). 

A. Tests performed 

Tests performed on a third-scale impact limiters and a dummy package included 

three 30' drops (side drop, slapdown and end drop) and one 40" drop onto a 

puncture pin. Accelerometers were placed on the dummy package. 

B. Description of the methods or analyses used in tests 

The test goals were: 

1. validation of calculated acceleration values, 

2. demonstration that the crush depths are acceptable, 

3. demonstration of the adequacy of the impact limiter enclosure and 

attachment design, 

4. evaluation of the effects of low temperature (-20 °F) on dynamic 

performance of the impact limiters, and 

5. evaluation of the effects (puncture depth and shell damage) of a 40-inch 

drop onto a scaled 6-inch diameter puncture bar on a previously crushed 

impact limiter. 

The side drop orientation was chosen to generate the highest transverse 

acceleration as well as a significant deformation. 

The slap down orientation puts the highest load on the impact limiter attachment 

bolts, tie rods, and stainless steel shell. 

The end drop orientation causes the highest axial acceleration, while the pin drop 

orientation was chosen because it assures that the puncture impact absorbs 

100% of the drop energy. 
- 48 - 

The test package consisted of a third-scale model of the TN-40 transport 

package with impact limiters on each end. The impact limiters are attached 

to each other by thirteen, 0.5-inch-diameter tie rods, snug tight, and to the 

package with four, 0.5-inch bolts. The test package weighs approximately 

10,100 lb. and has maximum dimensions of approximately 87.0 inches long 

by 48.0 inches in diameter. 

Lifting and dropping the test article was accomplished using a mobile crane. A 

quick release mechanism was used to initiate the drop. It consisted of a 

hydraulic piston that loaded a bolt to failure releasing a shackle supporting the 

test article via a rigging system. 

An inclinometer was used to measure the initial angle (± 1°) of the test body 

longitudinal axis with respect to the drop pad (i.e., impact surface). A measured 

line, 30 feet long (+ 3.0, -0.0 inches), was attached to the lowest point on the test 

package in order to assure the proper drop height. 

The impact surface was a 2-inch thick steel plate attached to a concrete block 

weighing approximately 250,000 lb. resting on bedrock. This configuration can 

be considered as an essentially unyielding surface. 

A puncture bar made of cold-rolled steel was welded to the impact surface for the 

40 inch puncture drop. The pin was scaled to match the test article resulting in a 

2-inch-diameter pin with the upper end edges rounded to a radius of 

approximately 0.083 inches. 

Accelerometers were used to measure the impact g load for all drops performed. 

Twelve PCB Piezotronics 353B18 accelerometers were attached to aluminum 

blocks that were bolted to the test body at 0°, 90°, 180°, and 270° orientations at 

three elevations. 
- 49 - 

Drop Test Sequence 

Test 

Number

Drop 

Orientation

Drop 

Height

Impact 

Limiter 

Number

Impact 

Sequence Comments

1 

0° 

Side Drop 30 feet 

1 - Limiters 1 and 2 installed. 

2 - 

2 

64° 

CG Over 

Corner drop 

30 feet 

1 1st The 1 and 2 impact 

limiters were rotated 180° 

so the undamaged 

portion of the impact 

limiters face the pad. 

2 2nd

3 

0° 

Side Drop 

(2nd test) 

30 feet 

1 - The test body and limiters 

were rotated 90° so that 

an undamaged portion of 

the impact limiters faced 

the pad. 

2 - 

4 20° 

Slap Down 

30 feet 

3 1st Limiters 1 and 2 were 

removed and replaced 

with limiters 3 and 4. 4 2nd 

5 90° 

End Drop 30 feet 

3 1st Limiter 3 was removed 

and chilled at –20 °F for 

48 hours before being reinstalled on the test body. 

4 - 

6 

90° 

End Drop 

(Puncture 

Test) 

40 inches

3 1st 

Drop onto 2 inch 

4 diameter puncture bar. - 

7 

90° 

End Drop 

(2nd test) 

30 feet 

2 1st Limiters 2 and 4 were 

used. The center portion 

of limiter 2 was relatively 

undamaged by previous 

drops and thus provided a 

useable crush volume. 

4 - 

The following data were measured and recorded before, during and after each drop test 

listed in the table above. 

1. Prior to each drop test 

• Torque of the impact limiter bolts. 

• Impact limiter dimensions. 

• Height from test article to drop pad. 

• Angular orientation of the test article to the impact surface. 

• Atmospheric condition data (i.e., ambient temperature, wind 

speed, immediately and prior to the release of the test article). 
- 50 - 

2. During each drop test 

• Test article behavior on videotape. 

• Date and time of test. 

• Observations of damage or unexpected behavior of the test 

article. 

• Impact acceleration time histories (excluding the puncture drop 

test). 

3. Following each drop test 

• Observations of the damage to the test article on features other 

than the limiters (i.e., attachment bolts). 

• Measurements of deformation to each impact limiter to fully 

describe the extent of the damage include depth of internal and 

external crush of the impact limiter, overall thickness of each 

impact limiter after each test, and dimensions of impact footprint. 

C. Test Results 

The performance of the test program allowed to: 

• Verify the impact limiters are not dislodged from the package as 

a result of the drop. 

• Demonstrate the effectiveness of the impact limiter tie rods, 

attachment bolts, and stainless steel covers. 

• Provide data on the deformation of the impact limiters due to the drop. 

• Provide data on the acceleration experienced by the test 

package during impact. 

• Provide data on the impact limiter damage caused by a 40-inch drop 

on a 2 in. diameter puncture bar. 

As an example, the following table shows the maximum transverse 

accelerations measured by the accelerometers during the second 0° side drop 

(converted to full scale), as well as the maximum acceleration predicted by a 

computer program. 

Accelerometer 

Location 

Measured Transverse 

Acceleration (gs) 

(converted to full scale) 

Average Measured 

Transverse 

Acceleration (gs) 

Predicted Maximum 

Transverse Acceleration 

(gs) 

(Appendix 2.10.8 in SAR)

Top (2) 68 

Center of Gravity 50 57 51 

Bottom (10) 55 
- 51 - 

The following table summarizes the measured and predicted crush depths for the 

bottom impact limiter. A spring back of 0.50 inches is assumed (based on previous 

crush tests). 

Impact Limiter 

Number 1 

Impact Limiter 

Number 2 

Maximum Inside Crush Depth (in.) 1.44 1.50 

Maximum Outside Crush Depth (in.) 0.75 0.75 

Spring Back (in.) 0.50 0.50 

Total Crush Depth (in.) 2.69 2.75 

Predicted Crush Depth x 1/3 (in.) 4.52 

From the above table it can be seen that the measured crush depths are slightly 

less that those predicted by the computer program. It should also be noted that 

neither the neutron shield nor the trunnions would contact the impact surface 

during the impact. The distance between the outer diameter of the neutron 

shield and the outside diameter of the impact limiter is 7.16 in. Therefore, a 

clearance of 7.16 - 2.75 = 4.41 in. would remain between the impact surface and 

the neutron shield, based on the measured crush depth. Similarly, a distance of 

3.84 in. would remain between a trunnion and the impact surface. 

Both impact limiters remained attached to the package during and after the side 

drop impact. All of the tie rods and tie rod brackets remained intact, thus 

preventing separation of the impact limiters from the package. In addition, the 

impact limiter attachment bolts remained in place, in spite of damage to two of 

the eight bolting brackets. Only a single small opening in the stainless steel shell 

of each of the impact limiters was evident. Both openings consisted of a tear 

along the weld between two of the outer flat plates of the impact limiter. The 

tears were roughly 4 inches long. Despite these tears, all impact limiter wood 

remained completely confined within the shell. 

The results of the tests demonstrate that: 

• The loadings used in the basket and fuel rod cladding structural analyses 

bound the dynamic measured data. 

• Based on the applied loading and factor of safety, the package can 

withstand much higher loads than those resulting from the dynamic 

measured data. 

• The crush depths do not result in lockup of the wood in the limiters. 

• The crush depths for all the drop cases would not result in the neutron 

shield or trunnions impacting the target. 

• The impact limiter enclosure is structurally adequate in that it successfully 

confines the wood inside the steel shell. 

• The impact limiter attachment design is structurally adequate in that the 

impact limiters remain on the ends of the test dummy during and after all 

drop orientations. 

• The effect of low temperature (-20 °F) on the impact limiter wood is not 

available due to lost test data. However, based on a similar design (TN-
- 52 - 

68) chilling the impact limiter wood (-20 °F) will increase the g load 

roughly by 15% to 20%. 

• An increase of 20% in the accelerations for both axial and transverse 

directions is acceptable based on applied loading and resulting factors of 

safety shown in the analyses. 

• A 40-inch drop onto a scaled 6-inch-diameter puncture bar, as required 

by 10 CFR 71.73(c)(3), does not significantly damage the impact limiter, 

nor are there any indications of damage to the test dummy. 

• The impact limiters remain firmly secured to the test dummy, and the 

impact limiter wood is confined. 

13. Model No. HI-STAR 180 (Docket No. 71-9325) 

The information below was obtained from Section 2.7 in the Holtec International 

consolidated application dated May 29, 2009 (see ADAMS Accession No. 

ML14114A178). 

A. Tests performed 

No tests were specifically performed for the HI-STAR 180. For casks in this list 

that note “no tests,” 10 CFR 71.41 permits the use of analyses to demonstrate 

compliance with 10 CFR 71.73 test requirements. 

B. Description of the methods or analyses used in tests 

The applicant derived an LS-DYNA model of the HI-STAR 180 impact limiters 

consistent with the previously HI-STAR 100 benchmarked model. The HI-STAR 

100 benchmarked analysis was revised only to properly account for the 

compressive and shear strength properties of the honeycomb material in three 

directions. 

The structural qualification of the HI-STAR 180 package relies only on transient 

LS-DYNA analyses and static ANSYS analyses. LS-DYNA is used to predict 

peak rigid body decelerations and impact limiter crush behavior. ANSYS is used 

to determine stress/strain levels in the package components by applying peak 

decelerations from LS-DYNA. Conservative upper and lower bound strength 

properties were analyzed where physical test data was not available for a 

particular crush/shear direction. 

C. Test Results 

No tests were performed for the HI-STAR 180. 

14. Model No. HI-STAR 60 (Docket No. 71-9336) 

The information below was obtained from Section 2.7 in the Holtec International 

consolidated application dated May 29, 2009 (see ADAMS Accession No. 

ML091540454). 

A. Tests performed 
- 53 - 

No tests were performed specifically for the HI-STAR 60. 

B. Description of the methods or analyses used in tests 

The certification basis for the HI-STAR 60 was predicated on analysis only and 

relied on HI-STAR 100 test data solely to the analytical modeling capabilities with 

respect to rigid body dynamics. This preliminary analysis was designated as a 

benchmark study and consisted of simulation of HI-STAR 100 quarter-scale drop 

tests conducted by the applicant on the HI-STAR 100. The benchmarking of the 

HI-STAR 100 drop test provides additional assurance that the deceleration and 

gross deformation results obtained from the HI-STAR 60 evaluation are 

reasonably accurate and conservative. 

C. Test Results 

No tests were performed specifically for the HI-STAR 60. 

15. Model No. BEA Research Reactor (BRR) Package (Docket No. 71-9341) 

The information below was obtained from Section 2.12.2 and 2.1 in AREVA Federal 

Services, LLC, consolidated application dated May 29, 2009 (see ADAMS Accession 

No. ML112640462). 

A. Tests performed 

A series of free drop tests were performed on a half-scale model of the BRR 

package. The SAR presents test results, including time-history deceleration 

package body response traces and photograph records of deformations and 

damaged attachments of the impact limiters, for the initial series of three, 30-ft 

free drop tests and five puncture drop tests. The specific drop tests were: 

• 30-foot end drop 

• 40-inch puncture test oblique drop onto thicker end plate 

• 30-foot slapdown drop, with the longitudinal axis 15 degrees from vertical 

• 30-foot drop with CG-over-corner 

• 40-inch puncture where the puncture bar strikes the inside edge of the 

slapdown primary-end damage from 2nd drop test, above, 

• 40-inch puncture where the puncture bar impacts the end of the damage 

impact limiter from 2nd drop test, above, 

• 40-inch puncture test with CG-over-corner drop, with impact on the 

thinner conical shell material, and 

• 40-inch puncture test with the puncture bar striking the center of the 

slapdown secondary damage. 

B. Description of the methods or analyses used in tests 

The test articles were chilled generally between -10 °F and -20 °F. The impact 

limiter performance is demonstrated by tests of the half-scale, prototypical units 

and a dummy package body. 
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The primary means of recording the results of the tests was physical 

measurements and observations of the test packages (including impact limiters) 

before and after testing. Each free drop impact was recorded using 

accelerometers. 

C. Test Results 

Data obtained from the tests consist of both qualitative information with respect 

to observations about the package and the limiter and quantitative data obtained 

from the recorders. The data for each test include measured impact limiter 

deformation, strain gauge data and stress calculations (for the end drop and side 

drop only), and observations of the package and attachments. The strain gauge 

data were only presented for the end drop and the side drop since the loads 

developed in those tests are the most severe from an overall structural 

consideration. The end drop corresponds to the maximum axial loading 

condition, while the side drop developed the maximum lateral loading on the 

overall package body. 

Five puncture drops were performed on the half-scale certification test unit to 

demonstrate structural adequacy of the package. The tests showed that the 

puncture bar would neither penetrate beyond the impact limiter shell located on 

the flat bottom nor create a significant exposure of foam adjacent to the package 

to the containment seal. The impact limiters would remain attached to the 

package ends. Also shown in one of the tests was that the puncture bar would 

not enter the impact limiter through a side impact on the limiter shell and rip open 

a large area. For the package thermal evaluation, the tests provided bounding 

impact limiter damaged configurations for fire event modeling consideration. 

The tests demonstrated that the impact limiters were capable of limiting the 

package body deceleration to the design basis of 120 g applicable to all package 

drop orientations. The application notes that, although the impact limiters were 

damaged with some exposure of the foam, they remained attached to the 

package body. Also noted is that the damaged configuration is included in the 

thermal model for the HAC fire event analysis. 

Therefore, the value of 120 g was utilized as the bounding value to calculate and 

evaluate package body structural performance for all drop orientations for all the 

tests. 

16. Model No. TN-LC, (Docket No. 71-9358) 

The information below was obtained from Sections 2.6 and 2.7 in AREVA Inc., 

consolidated application dated November 30, 2012 (see ADAMS Accession Nos. 

ML12340A309 and ML12340A310). 

A. Tests performed 

No tests were performed specifically for the TN-LC. 

B. Description of the methods or analyses used in tests 
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The applicant demonstrates the structural capabilities of the package by 

analyses using ANSYS code. A third-scale model drop testing of a structurally 

similar packaging is used (Model No. NUHOMS MP197 transportation package), 

to benchmark the impact limiter finite element analysis model, which was 

subsequently adapted, for determining bounding deceleration g-loads for the 

package structural evaluation by analysis. 

C. Test Results 

No tests were performed specifically for the TN-LC. 

17. HI-STAR 180D (Docket No. 71-9367) 

The information below was obtained from the NRC staff’s safety evaluation report dated 

August 5, 2015 (see ADAMS Package Accession No. ML14211A015), that used Holtec 

International’s SAR dated July 16, 2014 (see ADAMS Package Accession No. 

ML14203A285), as its basis. 

A. Tests performed 

There were no tests performed specifically for the HI-STAR 180D. 

B. Description of the methods or analyses used in tests 

The licensing basis for the Model No. HI-STAR 180D package structural 

performance is predicated on analytical modeling rather than experimental 

testing. The LS-DYNA modeling approach had been determined to be 

adequately benchmarked for certifying the Model No. HI-STAR 100 package in 

computing cask rigid body decelerations for the free-drop accident conditions. 

C. Test Results 

There were no tests performed specifically for the HI-STAR 180D.