Evaluation of Supercell Methodologies Using ZED-2 Measurements

Abstract

As part of an effort to assess the supercell methods used to calculate the incremental cross sections representing reactivity devices, a benchmark study was performed by comparison with ZED-2 measurements. ZED-2 is a research reactor used to measure criticality, fine-flux and core-flux distributions for a given lattice arrangement. The measurements selected for the study included various absorbers similar to the light-water liquid-zone controllers and adjuster rods used in CANDU reactors. Two types of supercell calculations were tested by comparison with measurements: the DRAGON code and the WIMS-AECL/SPH/Modified-MULTICELL suite of codes. The flux shape calculated with the supercell codes inside and outside the absorbers was compared with available copper-activation measurements. A full-core ZED-2 model was set up for Reactor Fuelling Simulation Program (RFSP) calculations. The calculated global flux distributions were compared with measurements. The error in modelling the reactivity effect was expressed in terms of the error in the prediction of the change in critical height.