Planning for a radiological emergency at a nuclear power plant requires that procedures be identified for protecting the public in the event of an actual or possible release of radioactive material. Sheltering and evacuation are two primary courses of action which can be taken to effect “dose savings,” that is, to reduce whole body, thyroid, and lung exosure to radioactive iodine and other fission products. An announcement of a general emergency will precipitate action in two different decision-making arenas: (1) the public arena in which government officials must decide whether to order evacuation or sheltering, and (2) the private arena in which individuals and families must decide whether to follow the directives of public officials or to act on their own. Experiences with natural disasters and some technological disasters have led to the assumption that there will be a reasonably strong agreement between the decisions of government officials who are carrying out their charge to protect the public and the decisions of individuals who are trying to protect themselves and their families. In other words, governmental directives during an emergency will generally result in a large proportion of the population doing what they have been told to do.