Ongoing research aims to determine if a full-scale virtual reality mockup can be effectively used to reduce construction and maintenance costs of the next generation of nuclear power plants. A full-scale virtual mockup of Room 12306 of the Westinghouse AP1000 nuclear power plant provides the test bed for this research. Located in the auxiliary building, Room 12306 contains a number of construction modules and assemblies comprised of piping from 10 different fluid systems. The virtual mockup developed at Penn State is currently being evaluated for visualizing and testing the planned construction of Room 12306. Using the virtual mockup, the designer and contractor can evaluate, in 1:1 scale, a step-by-step installation sequence for the modules and piping assemblies for completeness and feasibility. Simulating a multiple-step installation sequence, the user can experience a human-in-the-loop, virtual construction of the yet-to-be-built space. Using software tools, the user may also interactively develop installation sequences by selecting modules and assemblies in the appropriate order. Two sets of experiments performed at Penn State ARL’s SEALab were used to determine the value added by using the virtual mockup to develop and visualize the construction schedule for Room12306. During the first experiment, two groups of Penn State construction management students were asked to use the virtual mockup and associated software tools to develop a construction sequence for Room12306 without any prior knowledge of the space. The groups were able to easily identify constructabilty issues and find opportunities for scheduling parallel activities, although they had no prior experience with the room. The second experiment asked two teams of experienced construction superintendents to develop a construction schedule for the space using drawings provided by the designer. The teams viewed and evaluated the schedules they developed in the virtual mockup. The teams used knowledge gained from this evaluation to develop an optimum schedule in the virtual mockup. The optimum schedule balanced the workload across three crews, resulting in a significant reduction in estimated construction time.