Chornobyl exclusion zone: current status and challenges

Abstract

Comparisons of the large nuclear accidents that occurred at the nuclear power plants in Chornobyl and Fukushima usually focus on the emission of radionuclides, the contamination area, doses to the public and liquidation workers, etc. However, little attention has been paid to various factors that affect decisions regarding the future development of these territories, such as the sociopolitical and economic situation in the countries during the accident and at the present time, the density and structure of the population, climate change, media coverage, and accessibility of information to the public. This article attempts to discuss the above factors, speculates about the paths for future development of both exclusion zones, and suggests the most promising areas for joint research in the future.

1. Introduction

Browsing ‘comparison of Fukushima and Chornobyl’, one can find dozens of papers, both scientific and mass media, comparing various aspects of the disasters, including the extent of radionuclide release (Steinhauser et al., 2014; Imanaka et al., 2015), reconstruction of doses, received by professionals who were involved in mitigation and consequences liquidation and the inhabitants of the affected areas (Suto et al., 2013; Hatch and Cardis, 2017; Mori et al., 2017), and analysis of the media coverage of the two disasters (Tomkiv et al., 2016). As the two largest disasters in the history of nuclear power, the accidents at the Chornobyl nuclear power plant (ChNPP) and Fukushima Daiichi nuclear power plant (FDNPP) are constantly compared in order to enhance knowledge and skills in disaster preparedness as a whole, and on nuclear safety and security in particular. Radionuclide composition of emissions and the wind rose at the time of the accident, soil types and ecosystem dose rates, and the number of evacuees are the main factors to consider when hypothesising about the future development of the exclusion zones in both Chornobyl and Fukushima. Nevertheless, there are significant differences between the two accidents in terms of the sociopolitical and economic situations in the countries during the accident and at the present time. When comparing these two accidents, it is also important to consider the significant leap in technology made by mankind in the last 25 years. Rather than duplicating the comparisons that have been made previously (Balonov, 2013; Hachiya and Akashi, 2016; Wakeford, 2016; Lucchini et al., 2017), this article will focus on assessing the current state of both radionuclide-contaminated territories, and making an educated guess regarding future development.

Today, 35 years since the accident at ChNPP, discussions about the status of the exclusion zone are ongoing. Although the territory of the exclusion zone was defined as a national reserve area in accordance with the Decree of the President of Ukraine (2016) (Chornobyl Radiation and Ecological Biosphere Reserve, 2016), proposals of returning it to economic use are discussed periodically by the Government of Ukraine. At the same time, the Government of Japan has a clear policy of returning people to the remediated areas of Fukushima Prefecture, gradually lifting the evacuation orders (Kawasaki, 2020; ‘Transition of evacuation designated zones ’, n.d.). Returning to the difficult-to-return zone and the 10-km zone in Chornobyl out of question out with this discussion.

To understand the current situation, it is important to be aware of several factors that affect the attitudes of the societies towards accidents.

the sociopolitical and economic situations and type of ownership in each country;

the population density and its dynamics after the accident, as well as the economic load of each territory before the accident; and

environmental factors, affected by climate change, disaster preparedness, and coping and mitigation strategies of the two societies.

2. Sociopolitical and economic situationS in each country

The difference in the sociopolitical systems in each country, the attitude of the population and governments to private property, and the readiness of the authorities to listen to the opinions of voters are some of the main factors that influence decisions on the status of contaminated areas.

At the time of the accident at ChNPP due to the socio-political system of USSR, residents were not allowed to have land in private property.

Polesie (north of Ukraine and south of Belarus, respectively) was a swampy, subfertile, and sparsely populated area, traditionally used for forestry.

The consequences of the Second World War in 1941–1944, and the policies of expropriation, collectivisation, and cosmopolitanism pursued by the USSR resulted in a specific attitude of the population towards private property and distrust of the authorities.

The destruction and significant reformatting of economic ties due to the collapse of the USSR, the lack of a legal framework for comfortable business, political instability, and open hostilities in the Ukrainian territory resulted in significant restrictions to the budget available for the ChNPP exclusion zone. Today, 35 years since the evacuation and decisions to exclude the territory from economic use, financing the development of this zone and associated research is not on the agenda for modern Ukraine.

All of the above created the preconditions for a specific attitude of Ukrainians towards evacuation, giving residents no legal basis for claims to the territory. The difficult economic situation in the 1990s and the abandonment of the infrastructure in the exclusion zone for more than 30 years since the residents were evacuated means that it has remained in state ownership. Although discussions on returning the exclusion zone to economic use have been ongoing for the past 10 years, the suggestion to transform the territory into the Chornobyl Radiation-Ecological Biosphere Reserve, joined to the Polesie State Radiation-Ecological Reserve (Republic of Belarus) to form a single reserve, seems the most reasonable.

At the same time, Japan, which is relatively isolated from political perturbations overseas due to its island location and ancient monarchical traditions, reached certain stability of the state system.

Inheritance traditions of land and buildings, and respect for private property, are deeply rooted in Japanese culture, and this determines the uncompromising will for the return of territory to the owners, while significantly limiting the countermeasures available for implementation by the Government of Japan.

The evacuation zone is located in the most advantageous territory from a geographic and economic point of view, namely the flat coast of the island, and is covered with soil that is optimal for farming. This area is most suitable for construction and, as a consequence, has a developed infrastructure, making an important contribution to the economy of Northern Japan.

The political system of Japan, which has been stable since the Second World War, has strong traditions of parliamentarism and a collegial government, and this significantly affects the decision makers. Society requires a unified approach to territory decontamination, which narrows the range of measures available for application, violating the choice of radioecologically and economically optimal measures to, to some extent, extensive and labour-consuming measures that aim to reduce the population's radiophobia.

The stable economic growth of Japan since the Second World War has allowed the country to fund radiological research, empowering post-accident decontamination processes.

Thus, significant social pressure on territory decontamination decision makers, the high economic congestion of the territory, and the need to obtain permits to work in the radionuclide-contaminated territory from its owners dictate the need for the fastest possible decontamination and return of territories to public use. To date, evacuation orders have been lifted for all zones designated as ‘restricted residence zones’ and ‘evacuation order preparation zones’, leaving only the significantly contaminated ‘difficult-to-return zone’ evaculated. The Government of Japan, together with the Japanese and international scientific communities (Wu et al., 2017; Evrard et al., 2019), are in active discussions about the development of countermeasures to reduce contamination in even the most contaminated areas.

3. Population structure

When discussing the future of the territories contaminated by both radiation accidents, it is impossible to ignore the population density of the countries, and, consequently, the need for living space, as well as the type of land use.

The current area of Ukraine is 603,500 km², of which 44,000 km² (7%) is under temporary occupation (Ministry of Reintegration of the Temporarily Occupied Territories of Ukraine, n.d.). The Ukranian population decreased from 49 million in 2001 to 42 million in 2020 (World Population Prospects – Population Division – United Nations, n.d.), with a density of 72.6 people km⁻². The growing role of agriculture in the country’s economy, as well as global trends towards urbanisation and population migration from manufacturing to service industries, has led to the concentration of the population in cities. The population density in Northern Ukraine, with its swampy and wooded territory, has always been below the national average; for example, in the regions adjacent to the exclusion zone, the population density ranges from 33.8 people km⁻² to 51.5 people km⁻², with clear negative population dynamics (All-Ukrainian Population Census, n.d.). Thus, even taking into account the efforts to restore the reputation and infrastructure of the exclusion zone, the return of evacuees is not in the scope of sociodemographic trends.

The current area of Japan is 377,900 km². The Japanese population decreased from 127 million people in 2001 to 126 million people in 2019, and the national average population density is 333 people km⁻² (Portal Site of Official Statistics of Japan, n.d.; World Population Prospects – Population Division – United Nations, n.d.). Although the average population density in Fukushima Prefecture is relatively low and amounts to 144 people km⁻², the distribution of residents is uneven due to the extremely mountainous terrain. Radionuclide fallout occurred in Futaba, Namie, and Okuma Towns with populations ranging from 6000 to 22,000 people [Fukushima (Japan): Prefecture, Cities, Towns and Villages – Population Statistics, Charts and Map, n.d.], and also affected two national highways. As such, returning evacuees to their homes and decontaminating the territory is a pressing issue for the national and prefectural governments.

4. Climate change

Japan’s position in the Pacific Ring of Fire (Hinga, 2015), which increases the risk of seismic and volcanic events, and the island location of the country, which leads to seasonal risk of typhoons and high precipitation periods, means that the level of disaster preparedness is high in Japanese society. Japan has well-developed plans for earthquakes and tsunamis (Hasegawa et al., 2018; Katoh et al., 2018), and the population is aware and well trained due to regular disaster preparedness drills. Until 2011, the risk of nuclear disaster had not been considered (Brumfiel, 2013), but the accident at FDNPP caused a significant shift towards nuclear and radiation safety. At the same time, due to the temperature buffering capacity of the Pacific Ocean, the climate change affecting Japan is milder compared with the sharp continental climate of Ukraine. These factors also exist in the evacuation zone of FDNPP. However, the disaster response infrastructure has been restored along with the rest of the infrastructure of the newly populated cities, and therefore the climatic changes of the last decade have had no direct effect on the prospect of returning the evacuation zone of FDNPP to economic use.

The exclusion zone in Chornobyl is located in the middle of Eastern Ukraine, with a sharp continental climate. Historically, swamps in this area were drained (Hostert et al., 2011), resulting in a significant (artificial) ecosystem shift. The exclusion zone is subject to two paradoxically opposite processes. At present, due to limited human and material resources, drainage channels, previously used to ameliorate swamps, are clogged, leading to re-waterlogging of the area. At the same time, due to global climate change, the entire territory of Ukraine, including the exclusion zone, has been subject to droughts in the past 10 years, which, in turn, has provoked dust storms and forest fires (Ager et al., 2019). In addition, due to the location in the interior of the continent, as well as climatic changes that were not predicted, neither the population nor the Government of Ukraine are used to responding quickly to emergencies, which leads to lengthy public debate, delayed response, and a lack of a clear government strategy on risk management or disaster preparedness. Climate change has made a significant contribution to the further development of the exclusion zone, which is further complicated by the prohibition of economic activity in this area as the territory belongs to the nature reserve fund.

The accidents at ChNPP and FDNPP are, without doubt, the largest incidents that have resulted in the release of radionuclides into the environment. Nevertheless, the accidents are strikingly different in terms of the socio-economic situation, humanitarian issues, informational factors, climatic profile, and strategies for future development. The exclusion zone of ChNPP, excluding the 10-km zone contaminated by transuranium elements, has been converted into a biosphere reserve (Chornobyl Radiation and Ecological Biosphere Reserve, 2016) in order to prevent the spread of radionuclides outside the contaminated zone, and also to form a space for the preservation of native flora and fauna. A unique open-air laboratory is under construction in the ChNPP exclusion zone, which will allow the study of short- and long-term radioecological effects in the wild. At the same time, the FDNPP evacuation zone, excluding the difficult-to-return zone, has been decontaminated successfully, and work is underway to restore the infrastructure and return people to the remediated territories. Museums and memorial complexes to honour the victims of the Great East Japan Earthquake are opening in the restored territories, and innovative approaches to clearing the territory; land reclamation; and psychological, medical, and social adaptation of migrants and individuals affected by radiation damage are tested here. Development of the territories affected by the two largest radiation accidents is moving in two opposite directions, allowing professionals who have the opportunity to work in both exclusion zones to study the entire spectrum of the consequences of radiation accidents, and the options for society’s response to them. As a result of detailed study of the approaches in both countries, and the cooperation of scientists and decision makers, it will be possible to develop new, improved strategies to respond to radiation accidents, taking into account not only the type of radionuclide contamination and the environmental factors, but also the socio-economic background of the contaminated territory.

At the same time, the views of both countries on the future of the most contaminated areas of the exclusion zones are surprisingly identical. Both Ukraine and Japan unanimously chose these territories as the most suitable to handle high- and low-activity radioactive waste. Japan chose to store bags with radioactive soil, removed from the entire contaminated territory, in the FDNPP exclusion zone, and Ukraine constructed storage facilities for spent nuclear fuel and opened a solid waste reprocessing factory in the ChNPP exclusion zone.

5. ConclusionS

Summarising all of the above, it is important to emphasise the importance of the joint work of international, Japanese, and Ukrainian professionals in radiobiology, radioecology, and modelling of the environmental response to radiation disasters. The joint work of multi-national and multi-disciplinary groups will make it possible to study the migration paths of radionuclides comprehensively in both anthropogenic-affected (Japan) and natural (Ukraine) environments, and will also provide an opportunity to improve countermeasure plans in case of future disasters, taking into account social and humanitarian aspects.

The most promising areas for joint research are:

the use of robotics for remote assessment of the radiation situation: Japan’s wide access to the latest technologies and the possibility of testing them in the ChNPP exclusion zone with minimal administrative obstacles and public outcry;

conducting sociological research with a single experimental design for both exclusion zones;

the development of dosimetric monitoring systems and their adaptation to work in conditions of high and low anthropogenic pressure;

the development of a training programme for specialist-mediators capable of broadcasting the results of radioecological research to the general public; and

continuing to study the response of ecosystems to radionuclide contamination – conducting research with a general design which will simplify the interpretation of the results.