Time-dependent neutronics model of nodal neutronics program Ants
Antti Rintala, Unna Lauranto
Abstract
Ants is a nodal neutronics program developed at VTT since 2017. Ants solution method for the nodal diffusion equation is based on the function expansion nodal method (FENM) and analytic function expansion nodal (AFEN) method. Ants supports rectangular, hexagonal and triangular nodal geometries. The solution methodology of Ants extended to solve time-dependent problems is presented in this work. The performance of Ants is presented for all three geometry options in a series of established two- and three-dimensional numerical time-dependent benchmarks for both rectangular and hexagonal lattices. The Ants results agree with other published nodal program results, especially if the problem is not sensitive to control rod cusping effects or a fine enough axial mesh is used.