EU-CIS joint study project 2. Conceptual framework of intervention level setting

Long-term protective measures taken in the CIS following the Chernobyl accident included relocating people from the most contaminated areas as well as continuing the restrictions on using foodstuffs contaminated with ¹³⁷Cs. The levels at which these countermeasures were introduced or still are being introduced for dose-saving purposes have been used to estimate avertable doses based on population distributions on both dose rate and surface contamination density of ¹³⁷Cs in space and time. The averted and avertable doses have been quantified by parameters of these distributions and intervention levels for relocation and foodstuff restrictions. The countermeasure efficiencies in agricultural production and various protection strategies in the agrosphere in Russia have been investigated. In addition, methods for estimating avertable radiation risks as well as residual risks from continuing exposures in terms of age-dependent radiation risk factors have been suggested. The sensitivity of changing intervention levels expressed in terms of changes in costs and avertable collective doses have been explored. The application of the present methodology in the decision-making process following a nuclear accident is discussed. Suggestions are made for including the methodology in simple models to be used for aiding decision-making on introducing protective measures.