Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

This paper presents a methodology for time-dependent neutronic analysis of non-uniform deformations
in Sodium Fast Reactor (SFR) cores using the coordinate transformation method. The
methodology was developed for the 3D nodal diffusion code DYN3D, which uses a regular nodal
mesh for its neutronic solvers. To test the methodology, static and dynamic reactivity variations
induced by a postulated pressure spike in the Phenix reactor leading to dynamic core deformation
were calculated with DYN3D. The time-dependent mechanical core deformations were evaluated
beforehand and provided to this study as CAD geometry snapshots. The validity of the method
was demonstrated by comparing the DYN3D results against a Monte Carlo reference solution.
Static reference calculations were carried out beforehand using the Monte Carlo code Serpent,
with CAD snapshots directly used as geometry inputs. The study achieved a very good agreement
between diffusion calculations using coordinate transformation and the MC calculations using
deformed CAD geometries.