Under normal operation, nuclear plants release small amounts of radioactive waste. In the unlikely event of a severe accident, followed by successive failures of physical barriers and problems in the control systems and protection of the reactor, the release of radioactive materials can become significant. The problems generated from these catastrophic events can lead to the achievement of high levels of radioactivity in the vicinity of the plant, posing a threat to humans, society and local life. In either of these scenarios, appropriate models and computational tools are needed to predict...