High-Fidelity Coupled Monte-Carlo/Thermal-Hydraulics Calculations

¹ Karlsruhe Institute of Technology (KIT), Institute for Neutron Physics and Reactor Technology (INR), Germany Hermann-von-Helmholtz-Platz 1, Geb. 521, 76344 Eggenstein-Leopoldshafen
² The Pennsylvania State University, 206 Reber Building University Park, PA 16802, USA

^* Corresponding Author, E-mail: Aleksandar Ivanov, aleksandar.ivanov@kit.edu

Abstract

Monte Carlo methods have been used as reference reactor physics calculation tools worldwide. The advance in computer technology allows the calculation of detailed flux distributions in both space and energy. In most of the cases however, those calculations are done under the assumption of homogeneous material density and temperature distributions. The aim of this work is to develop a consistent methodology for providing realistic three-dimensional thermal-hydraulic distributions by coupling the in-house developed sub-channel code SUBCHANFLOW with the standard Monte-Carlo transport code MCNP. In addition to the innovative technique of on-the fly material definition, a flux-based weight-window technique has been introduced to improve both the magnitude and the distribution of the relative errors. Finally, a coupled code system for the simulation of steady-state reactor physics problems has been developed. Besides the problem of effective feedback data interchange between the codes, the treatment of temperature dependence of the continuous energy nuclear data has been investigated.