Application of the Full 3-D Collision Probability Method to Randomly Distributed Spherical Fuel Elements

Abstract

The analysis of VHTR fuel tends to be difficult when using deterministic methods currently employed in lattice codes notably because of limitations on geometry representation and the stochastic positioning of spherical elements. The method proposed here and implemented in the lattice code DRAGON is to generate the positions of multi-layered spheres using random sequential addition, and to analyze the resulting geometry using a full three-dimensional spherical collision probability method. The preliminary validation runs are consistent with results obtained using a Monte-Carlo method, for both regularly and randomly positioned pins.