An intercomparison of calculations made for thermal reactor pin cell benchmarks and the small Los Alamos fast critical assemblies using the JEF 2.2 library in different codes. An intercomparison study organized by the JEF project, with contributions by Britain, France, Germany, The Netherlands and Switzerland

These benchmark intercomparison studies have been undertaken to investigate the accuracy of calculation methods, by adopting the same nuclear data library, JEF-2.2, in all codes. The objective has been to estimate the uncertainties arising from approximations in the methods and to provide guidance in investigations of the sources of discrepancies. In this first phase the intercomparisons have been confined to very simple models, LWR pin cells without leakage and fast spectrum bare homogeneous spheres. The pin cell calculations with leakage treated via a buckling gave large differences and there is no reference method available relative to which the methods can be compared. For this reason, other benchmarks have been proposed to evaluate methods of treating leakage in thermal reactor cell calculations. (author)