The main goal of future fundamental work on the Sarcophagus is aimed at reducing the probability of an accident arising.
Chornobyl Shelter Fund (deployed 1997), managed by the European Bank for Reconstruction and Development (EBRD), which sets out the tasks to be executed for the successful covering of Chornobyl’s unit 4 within eight to ten years. That project will transform the existing temporary structure into a secure and environmentally sound system.
Much of the radioactivity from the destroyed unit (up to 97%) has remained in the Exclusion Zone around the Chernobyl NPP. In certain locations the contamination density is so great that radioactive wastes are essentially lying on the soil surface. The highly active wastes are situated in the Sarcophagus and at the disposal sites. However, the conditions of their storage are far from complying with radioactive waste storage requirements.
At the same time the Exclusion Zone is a safety barrier between radioactivity sources and the population. The most contaminated area is separated from inhabited areas by barbed wire and entry to this zone is restricted to professionals with special admission permits. In this manner, from the viewpoint of radioactive protection, distance acts as a protection barrier from radionuclides in the Exclusion Zone. Owing to the countermeasures implemented air and water transport and the unsanctioned removal of radionuclides do not present a danger for the population for as long as the restricted zone exists.
Full rehabilitation of the Exclusion Zone currently and during following 10-20 years is not possible owing to: the existence of "hot spots" of contamination near residential areas; the possibility of local radioactive contamination of groundwater; the hazard associated with the possible collapse of the Sarcophagus; and severe restrictions imposed on diet and lifestyle .
Outside the Exclusion Zone
In the sixteen-year post-accident period, most of the local population living in the contaminated areas have already received 60-80% of their anticipated life-time dose. Over the next 10-20 years, the main dose-related radionuclide in these areas will be 137Cs, accounting for up to 90% of the total additional dose. The internal dose, caused mainly by the consumption of locally-produced contaminated foodstuffs, accounts on average for 40-60% of the total “Chernobyl” dose, and in critical areas - up to 95%. In these critical areas countermeasures should focus on the consumption of "clean" foodstuffs.
Consequences of the accident for public health (exposure doses)
At present, the harm caused to the public by radionuclides outside the Exclusion Zone is mainly due to internal exposure from contaminated foodstuffs.
This risk is comparable with risk attributed to exposure from natural radioactivity sources. However, considering the complex consequences of the accident, countermeasures aimed at increasing the longevity and caring for the health of the stricken population are in any case necessary at this stage.
The dramatic increase in radiation-induced thyroid cancers in children and adolescents in Belarus, Russia and Ukraine, which has been observed since 1991, continues during following 15 years. Further thyroid cancer cases are expected in the coming decade in persons who were exposed as children and also in the clean-up workers of the accident in 1986.
The possible increase noted in the incidence of leukaemia above the spontaneous level in the Russian clean-up workers and the fact that there is no increase in the incidence of leukaemia among the adult and child population living in the contaminated areas of the three
States should be the subject of further standardized epidemiological studies. It is especially important that all diagnoses of leukaemia be confirmed by an international team of haematologists;