In the second half of the 20th century, as a result of the action of mining and processing enterprises of the nuclear fuel cycle, dumps and radioactive tailing dumps were formed on the territory of several CIS countries - former Soviet republics. The issues of their impact on the environment require solution of waste management tasks. A considerable mass of radioactive waste enters the environment through the atmosphere. This paper considers a set of models describing the processes associated with the atmospheric spread of radioactive contamination at various stages of tailing dumps operation. The results obtained by different types of models are analyzed and model data and instrumental measurements are compared. Environmental risks associated with different options for the development of the radiation situation are analyzed. The book is intended for a wide range of scientists, students, post-graduates, and specialists in the field of radiation ecology, related by the nature of their research to the tasks of radioactive waste management.