1. Air Transport of Commercial Spent Nuclear Fuel (SNF) Assemblies
Giancarlo Pena, (Student)
Florida International University
Dr. M. Jonathan Haire, Mentor
Oak Ridge National Laboratory
Acknowledgements
Dr. Seokho Kim, dynamic crash analysis
Dr. Bryan Broadhead, radiation shielding

2. Background
The shipment of used/spent fuel from reactors to permanent disposal site is an integral part of nuclear energy
Air transport of research reactor SNF has already occurred among countries because of geographical and political reasons
This work examines the technical feasibility of transporting commercial SNF casks by aircraft in the U.S.

3. Fuel, Canister, and Cask
The NAC (UMS) cask provided the base-line dimensions and weights
The number of fuel assemblies inside the canister of the transport cask was reduced (as were the outside and inside diameter) to decrease cask weight
Weights for 15, 18, 21, and 24 fuel assembly waste packages were calculated

4. Optimal One Square SNF Assembly Packing Arrangements in a Cylindrical Canister (1.11 cm spacing is placed among SNF assemblies and canister ID)

5. Overview of SNF Air Transport Cask Dimensions

6. The IAEA Provides a Framework for Certification of a Air Transport, Type C, Cask
The tests for Type C cask are slightly more stringent than those for Type A and B casks. For example
The fire test is for one hour, not 30 minutes
Impact tests are more drastic, a target velocity of not less than 90 m/s

7. Aircraft Description Three different aircraft options were analyzed
Boeing F
Payload 112 tons
Boeing ER Freighter
Payload 122 tons
Boeing 747-8F
Payload 154 tons

8. This is a Boeing 747-8F (154 payload), (photo provided by China-Airlines)

9. Shielding Test
The CAPSIZE, SCOPE, and SCALE codes were used for radiation shielding calculation
These codes helped establish the shielding thickness of the transport cask
A series of SAS1 SCALE code calculations were performed as a benchmark to assure the accuracy of the CAPSIZE and SCOPE codes
All radiations calculations assumed steel as the gamma shield and Holtite® for the neutron shield

10. SNF Package Characteristics using CAPSIZE
Number of SNF Assemblies 24 21 19 15
Canister outside diameter (cm)
159 (63 in.)
147 (58 in.)
142 (56 in.)
127 (50 in.)
Gamma shield thickness (cm)
29.21 (11.15 in.)
28.12 (11.07 in.)
27.94 (11 in.)
27.71 (10.91 in.)
Neutron shield thickness (cm)
11.98 (4.72 in.)
11.86 (4.67 in.)
11.73 (4.62 in.)
11.56 (4.55 in.)
Transport cask outside diameter (w/o impact limiters
254 (100 in.)
(94 in.)
(92 in.)
(87.5 in.)

11. Cask Weights 24 SNF 21 SNF 18 SNF 15 SNF Fuel (kg) 14,520 14,404.1
Results using capsize model and UMS model, approximate SNF package weights
(Note: the lift-weight of a Boeing 747 Air Freighter is about 112 tons)
24 SNF
21 SNF
18 SNF
15 SNF
Fuel (kg)
14,520
14,404.1
12,346.4
10,288.6
Canister (w/o fuel) (kg) NAC Model
21,000
19,000
18,700
17,600
Cask and radiation shielding (kg)
115,714
102,763
100,442
89,309
Impact limiters (kg)
48 tons
Total weight (kg)
169 tons
150 tons
148 tons
138 tons
Inner & outer Gamma shielding liner = 0.95 cm for the four assemblies’ configuration.
Inner & outer Neutron shielding liner = 0.95 cm for the four assemblies’ configuration.
Fuel dimension = 22.1 cm for the four assemblies’ configuration.
Canister Length = cm for the four assemblies’ configuration.

12. Impact Dynamics
Aircraft crash analysis using the CTH code indicates that there is No deformation of the fuel canister at the maximum impact test speed of 90 m/s

13. Impact Analysis of Aluminum Honeycomb Material

14. Impact Analysis of Solid Aluminum Material

15. Costs for Air Transport
The cost of a “typical” trip (Memphis to an U.S Air Force base outside Las Vegas) is $150K
There will be ~72,400 SNF assemblies in storage in the U.S by the year 2015
If there is 21 SNF assemblies air shipment, there is therefore ~7,000 air shipments
The resulting cost is ~1/2 the cost of building a 319 mile railway spur the Yucca Mountain geologic repository

16. Conclusions
The calculated total waste package weights for 21 SNF assemblies is ~150 tons
Therefore, this Boeing 747-8F can lift and air transport the reference 21 SNF assemblies TAD canister
Computer simulations of impact tests indicate the a TAD canister will survive without rupture
The cost of air shipments of all SNF is less than constructing a railroad to Yucca Mountain
The necessary infrastructure, aircraft, airports, etc already exists. The primary obstacle is licensing a type C air transport cask, and ground transport to the departure airport

17. Future Work
The next step consist in analyzing this cask using Ls- Dyna impact code
3-D analysis
Use different materials for impact limiters trying to reduce weight without reducing the impact qualities
Thermo analysis