During transport and storage of spent nuclear fuel sub-criticality, protection of environment against radiation, and residual heat removal have to be ensured.

The paper describes the evaluation of modeling and calculation of temperature field for transport container C-30.

The aim of thermal calculations of transport container is to prove that residual heat produced by spent fuel could be safely led away without any damage to the fuel and to the container. All previous calculations considered the inventory of the container (spent fuel assemblies, cask, and water) as a homogenous entity with internal heat source.

3D model was created using ANSYS CFX software. It models in a simply way fuel assemblies as well as a cooling medium flow.

Each spent fuel assembly is divided into two parts. The central circular part represents the area of water between fuel pins. This part does not produce any heat. The rest of the assembly is bordered by hexagon on the outer periphery and by a circle inside of the fuel assembly. Only this part is responsible for heat production.

The calculations were made for residual heat output of 5, 10, 15, 20 and 24 kW.

The results were compared with experimentally obtained values.