A two-step concept to derive a consistent set of intervention levels for radiation emergency planning and to translate international recommendations into practical guidance.

A two-step concept is proposed in order to derive a consistent set of intervention levels for early (sheltering, evacuation) and late (relocation/resettlement, returning) protective actions that have to be considered in radiation emergency planning. In the first step, the dose ratios of the projected effective doses have to be calculated for four defined time periods, which correspond with the integration times for sheltering and relocation. In the second step, it is necessary to adopt an intervention level for one protective action or a more general reference level for a certain time period as, for example, the reference level recommended by the International Commission on Radiological Protection (ICRP) Publication 103 in 2007. The adopted intervention level or reference level and the relationships between the projected effective doses are used to derive a consistent set of intervention levels for early and late protective actions. To illustrate the two-step concept, four sets of intervention levels are exemplarily derived for two accidental releases from nuclear power plants.