A virtual reality system was developed for computational and graphical modeling and simulation of radiation environments. This system, called Virtual Radiation Fields (VRF), demonstrates the usefulness of radiological analysis in simulation-based design for predicting radiation doses for robotic equipment and personnel working in a radiation environment. The system was developed for use in determining the radiation doses forobotic equipment to be used in tank-waste retrieval operations at the Hanford National Laboratory. As a reference case, specific application is made to simulate cleanup operations for Hanford tank C-106. A three-dimensional model representation of the tank and its predicted radiation levels are presented and analyzed. Tank cleanup operations were simulated to understand how radiation levels change during the cleanup phase and to predict cumulative radiation doses to robotic equipment to aid in the development of maintenance and replacement schedules.