Please look at the following cloud-mass simulation of the 1999 Tokaimura nuclear power accident. You can click 'refresh' on your browser to replay it as many times as you need to.
The Tokaimura nuclear power accident caused direct human exposure, illness and death, and forced 300,000 neighbors to shelter-in-place for 24 hours. Above is a near-real-time simulation of the movement of the air mass polluted by the accident. This was the first use of the a new French model for such simulations, and was thus more useful for demonstrating response capacity and cloud-mass movement, rather than tracking the radioactive content of the cloud, which could not be determined immediately (Laboratoire de Météorologie Dynamique, Centre National de la Recherche Scientifique, Paris).