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
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.
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
Optimal One Square SNF Assembly Packing Arrangements in a Cylindrical Canister(1.11 cm spacing is placed among SNF assemblies and canister ID)
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
Aircraft Description • Three different aircraft options were analyzed • Boeing 747-400F • Payload 112 tons • Boeing747-400ER Freighter • Payload 122 tons • Boeing 747-8F • Payload 154 tons
This is a Boeing 747-8F (154 payload), (photo provided by China-Airlines)
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
Cask Weights 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) • 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 = 435.86 cm for the four assemblies’ configuration.
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
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
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
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