Probabilistic risk assessment (PRA) techniques and the lessons learned from previous PRA studies were used to evaluate the effectiveness of various design alternatives for the Westinghouse advanced pressurized water reactor design. This evaluation was done successfully at the design stage prior to the licensing stage and is probably the first example of such an application for a nuclear power plant design. Three measures of risk were utilized: plant core melt frequency per year, severe fission product release frequency per year, and economic risk to the plant owner in terms of present-day dollars. All plant configurations considered met or exceeded the safety criteria associated with regulatory requirements. The comparison of different alternatives was performed iteratively; after each iteration, the system most effective in reducing the total plant core melt frequency was chosen and added to the base plant configuration. The iterations were terminated when a predetermined cutoff level was reached. Probabilistic risk assessment techniques provide a viable method to create additional decision-making information at the plant design stage.