Training and testing on the usage of a hand-held radiation detector. We developed this VR application for the nuclear power plant in Pickering, Ontario. An operator places a virtual radiation source on the table and the trainee has to find it. A mathematical model, in conjunction with a physical simulation, results in a highly accurate and responsive virtual Geiger counter. This test can be conducted in an office or even at home, without expensive equipment and without exposing trainees to a harmful radiation.