MODELLING STRUCTURAL LOADING OF USED NUCLEAR FUEL UNDER CONDITIONS OF NORMAL TRANSPORTATION

• Published in: Ceramic Engineering and Science Proceedings pp. 95 - 110
• Main Authors: Geelhood, K, Adkins, H, Sanborn, S, Koeppel, B, Klymyshyn, N
• Format: Journal Article
• Language: English
• Published: 01.01.2015
• Subjects: Assemblies; Barrels (containers); Casks; Ceramics; Fatigue failure; Modelling; Plastic deformation
• ISBN: 9781119040279; 1119040272
• ISSN: 0196-6219

Modelling was used to study the loads experienced by used pressurised water reactor fuel rods transported 3000 miles by rail in typical transport packaging. Finite element modelling was used to study the behaviour of individual components, including the cask restraint structure, the cask, the basket and the fuel assemblies. Two failure criteria were established: fatigue loading for loads which caused very little or no plastic deformation; and for loading which resulted in significant plastic deformation. It was established that the maximum loads were significantly less than the yield stress, such that the second criterion was unnecessary. The model was validated using an instrumented simulated load on a fuel assembly shaker table. It was established that the most sensitive factors were the cladding elastic modulus, the spacer grid stiffness, the spacer grid location, and the gaps between the assembly and the cask. It was determined that the total damage from the worst shock and vibration cases was approximately 18% of the expected fatigue limit, and that therefore the fuel rods were not expected to fail during transport.