The Zeus experiments have been designed to test the adequacy of 235 U cross sections in the intermediate energy range. The detailed modeling of the second Zeus critical experiment with the MCNP Monte Carlo code is described, and calculated results are presented. In addition, a series of modeling simplifications is described that transforms the detailed representation into a benchmark configuration, and the reactivity impacts of those simplifications are assessed. The end product of these simplifications is a relatively straightforward model with a k (sub eff) that is only slightly different from that for the actual critical configuration.