A pure dynamic Monte Carlo code for the neutronic analysis of nuclear reactors

Abstract

Transient analysis is of great significance in the safety and economic assessment of nuclear systems. This kind of analysis is generally performed using simplified models such as the time-dependent diffusion theory or the point-kinetics approximation. Therefore, applying a more accurate approach seems necessary for situations exceeding the validity range of such models. Nowadays, with increasing computational power, special attention has been focused on the use of dynamic Monte Carlo methods due to their capabilities in simulating detailed geometries and physics. Hence, this paper attempts to develop a pure time-dependent Monte Carlo code called MC3-TD that is capable of modeling complex reactor core geometries considering neutrons and delayed neutron precursors as particles. Using this viewpoint during simulation, in addition to obtaining the spatial distribution of precursors, can also facilitate modeling their movements.Moreover, a new approach called the dynamic control method has been proposed for population control and its effectiveness has been compared to conventional methods. Several transient problems, including 2D and 3D geometries, have been used to assess the performance of MC3-TD and a highly satisfactory agreement has been found between the obtained results and reference data.