Effet de calculs DRAGON multicellules dependants de l'environnement sur les predictions DONJON pour le ACR-1000

For understanding the behavior of a nuclear reactor core, it is necessary to make a full core calculation in order to compute the neutrons flux. To obtain the neutrons flux, solving the Boltzmann transport equation is required. That is not a simple task and it is impossible to analytically fend the solution of the neutrons transport equation on a complex core. Following a series of approximations, it is possible to numerically solve the neutrons transport equation. The solution of this equation is done step by step. Calculations will be performed over the ACR-1000 core.;The objective of this work is to determine the impact of the environment on the cell properties of the ACR-1000. Those properties will be used to perform full core calculations. The neutron transport calculations are performed with DRAGON whereas for the diffusion calculation on a full core. The code DONJON will be used. The DRAGON reference transport calculation will be made on a single cell. Then, a series of calculations will be performed using DRAGON over two types of assemblies, the first modelling the core interior and the second, modelling the core periphery. Moreover, the fuel age will sometimes be homogeneous, sometimes heterogeneous. The fuel will be burned during six hundred days. One thus obtains libraries of macroscopic cross sections over a six hundred days interval for various simulations. Thereafter, we will determine the effect of a neutrons transport multicell calculation on various DONJON diffusion full core calculations. The macroscopic cross sections library formed during DRAGON calculations is used so we can extract the nuclear properties necessary for the diffusion calculation. The core will be modelled in two different ways. Firstly, the periphery effects will be observed using the properties resulting from the transport calculation made on the periphery assembly. Then, the interior effects will be observed using the cells properties resulting from an interior core heterogeneous assembly. Thus, this study will determine if the full core calculation can be carried out using single isolated cells properties.;The Advanced CANDU Reactor (ACR-1000) is a generation III+ heavy water moderated and light water cooled reactor. It is a 1200 MW(e) power reactor. Amongst the ACR-1000 design parameters that differ from the CANDU 6, the reduced lattice pitch and the use of light water coolant and enriched fuel are the three most important. Those features modify the behavior of the neutrons in the ACR compared to the CANDU 6. The impact of the tight lattice is that a cell is more strongly coupled to its neighbor.