The textbook covers the main issues related to the physical foundations of radiochemistry, the behavior of systems in which radionuclides exist or arise, as well as related problems associated with sources of ionizing radiation and their application. The textbook can be useful in the development of theoretical courses and in the performance of laboratory work. The manual is formed in such a way that it can be used in the study of a number of special courses for students of physical specialties and conducting practical and laboratory classes for students of different levels of training. Recommended by the UrFU Methodological Council for students studying in the areas of training 18. 03. 01 — Chemical Technology, 18. 05. 02 Chemical technology of modern energy materials, 22. 03. 01 — Materials Science and Technology .