Кондиціювання високоактивних твердих радіоактивних відходів у ядерному паливному циклі. Огляд методів та технологій. Частина 1

Abstract

This article provides an overview of global experience of radioactive waste (RAW) conditioning in terms of organizing and methodological approaches in using this RAW processing method, which were generalized in the documents of International Atomic Energy Agency (IAEA), in various analytical materials and scientific publications. Based on the analysis of available information materials, in different countries with developed nuclear fuel cycle, the conditioning is an integral part of the system of integrated RAW management, which includes the operations, during which they have be transferred to a form ensuring their stable chemical, thermal and radiation resistance for further transportation, storage and burial. The list of RAW produced during NPP operation and belonging to the conditioning, combines a variety of materials, which differ in their shape, concentration of nuclide activities and contamination type. The levels of specific activity of nuclides in the RAW vary from very low levels to extremely high levels inherent to spent nuclear fuel, which requires providing conditions of their subcriticality underway technological operations. It is stated that the most worked out method of RAW conditioning within the industrial scale is immobilization, which is aimed at wastes transformation into a solid form using the processes of their solidification after inclusion in any matrix, or inclusion in sealed casings. Radioactive components can be immobilized into a matrix material based on bitumen, polymers, cement, glass, ceramics, and glass ceramics by using two main processes: binding them into a material at atomic level — chemical inclusion or physical environment and isolation — encapsulation.