Evaluation of Irradiation Dose to Illegal Resettlers in the Chernobyl Exclusion Zone in Ukraine

After the Chernobyl Nuclear Power Plant (ChNPP) accident, the entire population within a 30 km zone around the Plant (the Chernobyl Exclusion Zone, or ChEZ) was evacuated from April to May 1986. Over 90,000 people from 81 locations in Ukraine and about 25,000 people from 107 locations in Byelorussia were evacuated through the middle of August 1986. Meanwhile, people started returning to their dwellings without permission, and they continue living today within the contaminated area. In 1986, 6,275 people lived there; in 1990, 1,064 people lived there. The majority of resettlers lived and still live within the southern trace of Chernobyl contamination. Towards the end of 1998, 537 people lived within Chernobyl and 14 surrounding villages, 65% of them women and 80% of them older than 55 years; 54 people worked in manufacturing (31 of them in Chernobyl). From an ethical and legal point of view, these resettlers are known as "self-settlers." From the scientific point of view, their resettlement has provided a unique opportunity to carry out dosimetric and medical monitoring directly in residences within the radioactively contaminated area. The basic resettlement sites of the illegal resettlers in the Ukrainian part of the ChEZ are within the southern trace of the Chernobyl fallout. The average density of 137Cs con- tamination in this zone does not exceed 15 Ci/km2 (555 kBq/m2). Radiation safety for these people can be provided by establishing radiation monitoring within the illegal habitation under the auspices of the National Program on the Chernobyl Accident Consequences Minimization in Ukraine. Developing a radiation safety system for these so-called "selfsettlers" enables one to determine the quantitative dependence of probabilistic stochastic effects and the rate of deterministic consequences from dose exposures by monitoring radiation levels where the self-settlers reside. Recommendations for resettler dose-exposure reduction are developed from the data obtained. The statistical data about self-settlers in the first years after the ChNPP accident were published in Gordeev et al., and are given in Table 1 of the Appendix. The selfsetters are interesting because they have been exposed to radiation for 17 years, but until 1998 they did not suffer the stresses usually associated with evacuation. The various features of models used to calculate self-settler dose exposure are discussed as an assessment of real radioecological risk for these people. The results