User's manual of the CORE SIM neutronic tool
Rapport, 2011

This report presents how to use the CORE SIM neutronic tool. The models and algorithms used in CORE SIM, as well as the validation and demonstration of the tool were already presented in two companion reports (Demazière, 2011a, 2011b). The novelty of the tool resides in its versatility, since many different systems can be investigated and different kinds of calculations can be performed. More precisely, both critical systems and subcritical systems with an external neutron source can be studied, and static and dynamic cases in the frequency domain (i.e. for stationary fluctuations) can be considered. In addition, the tool has the ability to determine the different eigenfunctions of any nuclear core. For each situation, the static neutron flux, the different eigenmodes and eigenvalues, the first-order neutron noise, and their adjoint functions are estimated, as well as the effective multiplication factor of the system. The main advantages of the tool, which is entirely MatLab based, lie with the robustness of the implemented numerical algorithms, its high portability between different computer platforms and operative systems, and finally its ease of use since no input deck writing is required. The present version of the tool, which is based on two-group diffusion theory, is mostly suited to investigate thermal systems. Although the tool cannot be compared in terms of accuracy to existing core simulators, the definition of both the static and dynamic core configurations directly from the static macroscopic cross-sections and their fluctuations, respectively, makes the tool particularly well suited for research and education. The tool is freely available on direct request to the author of the present report.

core calculations

static calculations

dynamic calculations

neutron noise


Christophe Demaziere

Chalmers, Teknisk fysik, Nukleär teknik


Övrig annan teknik



CTH-NT - Chalmers University of Technology, Nuclear Engineering