Protection of the public in the event of a large scale radiation accident: intervention criteria in Russian radiation safety standards RSS-99

The Chernobyl accident has stimulated revision of international and national guides and recommendations on radiation protection in the event of an accident resulting in radioactive contamination of wide territory and additional radiation exposure of large population. Decision-making criteria are established in RSS-99 to protect the population in the event of a large-scale accident applying to both urgent countermeasures at the early stage of an accident situation and protective measures the later stages. Criteria are formulated in a two-tier system of dose or contamination levels, implying that appropriate countermeasures are necessary (an upper level) or needless, if they involve violation of normal living routine of the public and disturbance in economic and social functioning of the affected territory (a lower level)