Tracking strategies in 3D axial geometries for a MOC solver

The solution of the neutron transport equation in 3D domains is a high resource demanding task. One of the most successful method of solution of this equation is the Method of Characteristics (MOC). However, the huge number of trajectories constitutes a serious issue in terms of memory needs and in terms of number of floating point operations. In this paper, we propose some techniques to compress tracking data and to speed up the MOC solver. These methods take advantage of regularities of 3D prismatic geometries. The new algorithms have been implemented in the 3D MOC solver TDT and applied to a typical UOx/MOx color set. (authors)