The VENUS-7 benchmarks. Results from state-of-the-art transport codes and nuclear data

For the validation of both nuclear data and computational methods, comparisons with experimental data are necessary. Most advantageous are assemblies where not only the multiplication factors or critical parameters were measured, but also additional quantities like reactivity differences or pin-wise fission rate distributions have been assessed. Currently there is a comprehensive activity to evaluate such measure-ments and incorporate them in the International Handbook of Evaluated Reactor Physics Benchmark Experiments. A large number of such experiments was performed at the VENUS zero power reactor at SCK/CEN in Belgium in the sixties and seventies. The VENUS-7 series was specified as an international benchmark within the OECD/NEA Working Party on Scientific Issues of Reactor Systems (WPRS), and results obtained with various codes and nuclear data evaluations were summarized. In the present paper, results of high-accuracy transport codes with full spatial resolution with up-to-date nuclear data libraries from the JEFF and ENDF/B evaluations are presented. The comparisons of the results, both code-to-code and with the measured data are augmented by uncertainty and sensitivity analyses with respect to nuclear data uncertainties. For the multiplication factors, these are performed with the TSUNAMI-3D code from the SCALE system. In addition, uncertainties in the reactivity differences are analyzed with the TSAR code which is available from the current SCALE-6 version. (orig.)