A Rational Model for the Off-Site Protective Action Selection During Nuclear Reactor Accidents

A statistical decision theory provides a rational theoretical model that enables an algorithm to select appropriate off-site protective actions. Existing knowledge on safety system and containment event trees, the spectrum of release states, and statistical decision theory were used to develop a model that accommodates actual and potential radiation risks and nonradiological risks such as risks of evacuation in selecting off-site protective actions. The usefulness of the model developed is illustrated by applying it to the Three Mile Island Unit 2 (TMI-2) scenario and comparing the actual decisions made with the decisions provided by the model. Conclusions drawn by modeling the TMI-2 related data are in general agreement with off-site protective actions taken. Finally, the model is used to illustrate the extremely low likelihood of the occurrence of accident scenarios that require evacuations beyond a 3.2-km radius and to support a plume exposure pathway emergency planning zone of 3.2 to 8 km for reduced source terms.