Validation of the HELIOS.HX code for high conversion light water reactor lattice analysis

The HELIOS.HX code has been developed for the design study of high conversion light water reactor (HCLWR) lattices. Analysis of the PROTEUS critical experiments at the Swiss Federal Institute for Reactor Research has been carried out as the first step toward validation of the HELIOS.HX code, and indications are that the accuracy may be at a higher or comparable level compared to that of WIMS-D, EPRI-CPM, and SRAC. In addition, comparisons with Monte Carlo calculations have also been performed for an HCLWR fuel assembly benchmark problem, showing that the accuracy is passable in the prediction of important nuclear characteristics, thereby indicating the validity of various approximations involved in the physics methods. These numerical results indicate that the code has basic potential as a tool for HCLWR lattice analysis, but covers only limited HCLWR lattice conditions