Moving meshes to solve the time-dependent neutron diffusion equation in hexagonal geometry

To simulate the behaviour of a nuclear power reactor it is necessary to be able to integrate the time-dependent neutron diffusion equation inside the reactor core. In particular, we will consider here VVER-type reactors which use the neutron diffusion equation discretized on hexagonal meshes. Several algorithms to integrate the time dependent neutron diffusion equation have been developed, by means of modal methods [1] or implicit methods for the time integration scheme. The present work is focused on developing method to deal with this problem on hexagonal geometries. Transients involving the movement of the control rod banks have the problem known as the rod cusping effect.