The main goal of fundamental work on the Sarcophagus is aimed at reducing the probability of an accident arising.
Chernobyl Shelter Fund (CSF), managed by the European Bank for Reconstruction and Development (EBRD), was set up in December 1997 to help finance the Shelter Implementation Plan (SIP), which sets out the tasks to be executed for the successful covering of Chornobyl’s unit 4 within eight to ten years. The SIP will transform the existing temporary structure into a secure and environmentally sound system.
The new shelter will eventually house an estimated 200 tons of nuclear fuel, 30 tons of fuel dust and around 2,000 tons of combustible materials that is still contained inside in the wrecked unit.
Phase 1 of the SIP, which involved mainly investigative projects, has now been completed. Emergency repairs to the Shelter’s roof beam and repairs to the ventilation stack have also been carried out. The project is now entering its second phase.
Much of the activity 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 .
Priority work activities in the Exclusion Zone are development and implementation of organisational and technical measures for reducing radionuclides migration outside the Zone (prevention of wash-out in periods of heavy rainfall, anti-fire measures in forests, stronger control over unsanctioned removal of radioactive waste).
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 is not currently 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 16 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 are being substantially reduced in much of the contaminated territory owing to natural processes (radioactive decay and depth of radionuclides) and the countermeasures implemented. As a result it is now theoretically possible to resettle people in some locations. However, after 16 (for 2002) years most of the buildings and industrial installations are dilapidated and resettlement would require substantial funds which are lacking in the present economic situation.
At present and during following 0-20 years, the harm caused to the public by radionuclides outside the Exclusion Zone is mainly due to internal exposure doses from contaminated foodstuffs .
These doses are comparable with doses 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.
Regarding the stochastic effects in humans caused by the ionizing radiation which is characteristic for the Chernobyl accident, the following conclusions and recommendations have been made:
- the dramatic increase in radiation-induced thyroid cancers in children and adolescents in Belarus, Russia and Ukraine, which has been observed since 1991, continues to this day. 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. To minimize the effects of thyroid cancer among the exposed population and the clean-up workers, measures aimed at timely detection and treatment of these cases should be implemented;
- 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;
- some data from Ukrainian scientists have indicated a possible increase in the other solid cancers (breast cancer, lung cancer, urologic cancers, etc.) among the inhabitants of the contaminated areas and the clean-up workers, and this should be the subject of further epidemiological study;
- to date, studies on possible genetic defects, hereditary diseases and congenital anomalies, due to radiation effects of the Chernobyl accident have not been developed sufficiently. It is therefore essential to embark on research in this field, paying special attention to the children of clean-up workers and to children from the most highly contaminated regions who were exposed in utero.
Health effects of the consequences of the accident have been observed in clean-up workers and the population of contaminated areas for which the radiation dose effect relationship has not been established. Further studies are necessary to include other possible causes, such as, psychological and social consequences, ageing and the effect of screening, so as to identify their relevance to the following data:
- the progressive deterioration in the health of the 1986-1987 clean-up workers in the three countries;
- for a number of non-oncological diseases (diseases of the endocrine system, cardiovascular diseases, psychoneurotic disorders, etc.), the morbidity indexes among the clean-up workers, the population living in the contaminated areas and evacuees from the Exclusion Zone statistically significantly exceed the national averages for all citizens.
A negative demographic trend has developed in the contaminated areas of Belarus, Russia and Ukraine. A variety of factors are resulting in a drop in the birth rate, a deterioration in women's reproductive health, an increase in complications during pregnancy and birth, and a deterioration in neonatal health. The public health services of the three countries should provide financial and social support to curb these negative trends.
The dynamics of change in the state of health of children affected by the Chernobyl accident in all three countries - Belarus, Russia and Ukraine - in the post-accident period is characterized by persistent negative tendencies: the morbidity rate is going up, the number of really healthy children is dropping, and disability is increasing.
The priorities for maintaining and improving children's health should be:
- ensuring the availability of qualified and specialized help;
- carrying out preventive, therapeutic and rehabilitation measures;
- integration and co-ordination of the efforts of Belarus, Russia and Ukraine, and international organizations to develop and implement high-performance methods for the diagnosis, treatment and rehabilitation of children affected as a result of the accident at the Chernobyl nuclear power plant.
In the next 10 years (until 2010) we can expect a continuing trend towards increase in morbidity for many types of disease and, possibly, malignant neoplasms, in view of the natural ageing of the affected cohorts. The cohorts given priority for follow-up should be persons who have had ARS, clean-up workers who received radiation doses of more than 250 mSv, evacuees from the 30-km zone, persons with a high irradiation dose to the thyroid gland, pregnant women and children living in contaminated areas and born to highly irradiated parents.
It is advisable that the governments of Belarus, Russia and Ukraine continue to improve the health care system and social protection of those suffering as a result of the Chernobyl accident, paying special attention to exposed individuals who qualify for continuing medical follow-up services.
As before, many people do not have a realistic understanding of the continuing radiological situation and risk. To a certain extent this is preventing rehabilitation of the contaminated areas. More emphasis should be given to the establishment of a reliable public information system about the radiological situation.
At the present time there is a need to review the strategy for compulsory relocation of people from the contaminated areas in terms of socio-psychological and radiological factors. The governments of the three countries should develop their policy regarding the contaminated areas with a view to creating the conditions for real economic regeneration and social rehabilitation.
In order to improve the health of the people, and the economic and social conditions in the radionuclide contaminated areas, it is necessary to:
- improve the national approach to restoration of the economic and social infrastructure in the contaminated areas and in places where there are large evacuee populations, and establish favourable conditions for attracting domestic and foreign investment;
- ensure improvement of the medical service, and social and psychological rehabilitation of the population evacuated from the Exclusion Zone and enforced resettlement zone;
- provide optimized systematic countermeasures aimed at reducing the internal and external doses to the population in all areas contaminated by "Chernobyl" fallout where countermeasures are justified;
- develop a social and psychological network aimed at overcoming de-stabilizing psychological factors in all groups suffering, above all, from the “Chernobyl accident victim” syndrome, which prevents those affected from taking an active part in social and economic activities;
- create a rapid and objective system for informing the public about the radiological situation in the region, the effectiveness of the countermeasures, the scientific and medical recommendations for protection against the effects of ionizing radiation and new ways of overcoming the negative
As far as possible accident consequences for health are concerned, any estimates of the total number of fatal and non-fatal cancers attributable to the accident should be interpreted with caution in view of the uncertainties associated with the assumptions on which they must be based. Such projections do, however, provide a perspective on the magnitude of the long-term impact and help in identifying areas needing special attention, both now (such as the incidence of leukaemia among the "liquidators" and of thyroid cancer among children living in "contaminated" areas) and in the future .
It is quite likely that the increase in the incidence of thyroid cancer will persist for several decades. The individuals concerned should continue to be closely monitored throughout their lives.
Despite the extensive scientific and medical study of radiation effects, a number of important questions remain unanswered as regards the human health effects of radiation. It is necessary to continue to support research into the biological effects of radiation.
Different factors, such as economic hardship, are having a marked effect on the health of the population in general, including the various groups exposed as a result of the accident.
Past experience of accidents where radionuclide release was not involved has shown that the psychological impact may persist for a long period.