Екологічна безпека Чорнобильської зони відчуження: техноприродні загрози від радіаційно небезпечних об'єктів і явищ

Abstract

Дисертація на здобуття наукового ступеня доктора технічних наук за спеціальністю 21.06.01 «Екологічна безпека» (технічні науки). – Національний авіаційний університет, Київ, 2020. В результаті проведення комплексу теоретичних і експериментальних досліджень у дисертаційній роботі запропоновано та обґрунтовано нові наукові положення, висновки та рекомендації, що розкривають особливості та закономірності впливу техноприродних загроз від радіаційно небезпечних об'єктів і явищ на рівень екологічної безпеки Чорнобильської зони відчуження. Проаналізовано еколого-радіаційний стан Чорнобильської зони відчуження та загрози його погіршення, методики дослідження впливу радіаційно небезпечних об'єктів і явищ Чорнобильської зони відчуження на довкілля та математичні моделі прогнозування їх екологічних наслідків. Виконано моделювання викиду у повітря радіонуклідів під час пожежі на об'єкті «Укриття», небезпечних процесів у сховищі відпрацьованого ядерного палива, викиду радіоактивних продуктів згоряння із зони лісової пожежі. Проведено оцінювання радіаційних небезпек об'єкта «Укриття», техногенно-екологічних небезпек сховища відпрацьованого ядерного палива «мокрого» типу, радіаційних небезпек лісових пожеж та їх екологічних наслідків. Науково обґрунтовано доцільність застосування методології прикладного системного аналізу для дослідження процесу поводження з радіоактивними відходами. Розроблено наукові засади систем моніторингу і менеджменту еколого-радіаційних небезпек Чорнобильської зони відчуження.

Dissertation for the scientific degree of Doctor of Technical Sciences in specialty 21.06.01 «Ecological safety» (technical sciences). – National Aviation University, Kyiv, 2020. As a result of a set of theoretical and experimental studies the dissertation proposed and substantiated new scientific provisions, conclusions and recommendations that reveal the peculiar features and patterns of impact of techno-natural threats from radiation-hazardous objects and phenomena on the level of environmental safety of the Chernobyl Exclusion Zone. This makes it possible to develop a scientific basis for the creation of new modern systems of environmental monitoring and management of the study area. The materials of the work have been tested, implemented and confirmed by the relevant acts. The main results of the work are as follows. The ecological and radiation conditions of the Chornobyl Exclusion Zone and the threat of its deterioration are analyzed. It has been determined that the greatest ecological and radiation threat to the environment is posed by potentially dangerous objects located in the Chornobyl Exclusion Zone, especially such objects as «the Shelter» and the Spent Fuel Storage Facility, where an accident involving the release of radioactive substances is possible. It is noted that one of the main tasks is an early detection of the causes of forest fires, minimization of their consequences and ensuring radiation protection of the population from the negative effects of radioactive clouds. A method for studying the occurrence and spreading of fire in the premises of «the Shelter» has been developed. The decision-making algorithm is implemented, which in the general case includes the stages of object safety identification, determination and analysis of decisions for compliance with the established requirements and criteria, implementation and monitoring of the effectiveness of decisions. The method of analysis of hierarchies for decision-making and informed decision-making is applied, weight factors of the considered aspects are offered, basic scales and a matrix for decision-making are developed. The method of research of forest fires in the Chornobyl Exclusion Zone as well as ecological and radiation consequences from them is determined. Also, the methods of measuring radioactive combustion products and control and measuring equipment for natural (field) and laboratory research are determined. A mathematical modeling of radionuclide emissions during a fire at «the Shelter» facility was performed. A model of the heat and mass circulation process in the spent nuclear fuel storage is proposed, which makes it possible to calculate the thermal reliability of objects under the influence of different types of loads with a given value. Model results of ground forest fires of coniferous forests and calculations of basic characteristics depending on the mass of forest combustible materials are obtained. The dynamics of smoke cloud movement in space and changes in the density of precipitation of volatile particles of radioactive combustion products on the trail of the smoke plume are modeled. According to the developed model of accumulation of radioactive combustion products in the human body, an assessment of their impact on the environment was carried out. The methodology for mathematical modeling of the technical condition of the complex «New safe confinement – the "Shelter"» is offered, which makes it possible to estimate the basic indicators of its reliability with a reasonable degree of accuracy, namely: probability and average time of trouble-free operation, gamma-percent resource or operating time during which the object does not reach the limit state with a given probability, the intensity of failures. The assessment of radiation hazards of the spent nuclear fuel storage of the «wet» type and their environmental consequences, namely: environmental consequences during the facility’s operation, safety of the fuel pool in conditions of uncertainty, structural reliability and thermophysical safety of the fuel pool, explosion hazards during the storage of spent nuclear fuel. The expediency of using the methodology of applied systems analysis to improve the process of radioactive waste management has been scientifically substantiated, which makes it possible to understand this process as a system with static and dynamic properties and take it into account in the general system of integrated environmental safety. The natural research of forest fires in the Chornobyl Exclusion Zone was carried out with the help of modern analytical equipment, which made it possible to obtain the values of radioactive contamination of the environment. According to the results of laboratory research, the processes of high-temperature sublimation of combustible forest material and removal of radioactive cesium into the air are modeled. A comparative analysis of the results of natural and laboratory studies with controlled forest fires was carried out. Radiation risk assessment during firefighting was performed. The radiation risk and the dose load for the population during forest fires with a radiation hazard factor are determined. Conceptual foundations for the development of special systems of control over the forest fire situation in the Chornobyl exclusion zone by means of an ultrahigh-frequency radiometer have been formed. A variant of creating a mobile laboratory complex for operational control over radiation conditions around radiation-hazardous objects in emergency and post-emergency situations, remote and contact control over radionuclides in air, soil, water, etc. to make management decisions to minimize the consequences of radiation accidents and emergencies related to radiation-hazardous factors have been proposed. Conceptual foundations of ensuring ecological and radiation safety on the basis of the created structural scheme of control and management of heavy radiation accidents have been developed. The practical significance of the obtained results lies in the implementation of the developed or improved methods, strategic directions and concepts for the monitoring and management of the state of ecological safety in the Chornobyl Exclusion Zone. With the direct participation of the author some results of the dissertation were implemented in the activities of organizations and institutions that are directly or indirectly related to the problem of environmental safety of the territory.