[en] The small zero-energy critical reactor VENUS contains a simple light water lattice which is easy to model and designed for testing lattice codes such as LWRWIMS. Experiments were carried out on a series of cold critical configurations of UO₂ fuel with a U-235 enrichment of approximately 4 per cent and PuO₂/UO₂ fuel with a U-235 enrichment of approximately 2 per cent and Pu enrichment of 2.7 per cent. LWRWIMS calculations of strongly absorbing gadolinium rods were compared with reaction rate distributions determined experimentally. Mn-55 reaction rates and power distributions were measured. In a few cases, no absorbing rods were present. The radial leakage was represented explicitly in the LWRWIMS modeling, and axial leakage by a geometric buckling. All core simulations were satisfactorily close to critical. Some significant disagreement remains between the calculations and measurements in the poison pin and at positions adjacent to the radial reflector. The depression of the manganese reactions rates by the gadolinium is overestimated by about 3 per cent while the increase in the reaction rate near the reflector is underestimated by approximately 6 per cent. (U.K.)