Handling toxic wastes during salvaging and rehabilitation of nuclear objects in north-west Russia

Abstract

Systematized information on toxic wastes produced during salvaging and rehabilitation of decommissioned nuclear and radiation-hazardous objects in the nuclear-powered naval fleet in north-west Russia is presented. The dynamics of their accumulation up to 2025 is estimated. Substantiation is given for the need to re-examine the existing system of handling wastes and searching for new solutions for decreasing the ecological risk by systematically reprocessing or eliminating them together with gaining an ecological advantage. Such an approach requires upgrading and developing infrastructure at the salvaging enterprises and objects undergoing rehabilitation. Several strategies are examined. The advantages and disadvantages of each strategy are evaluated according to safety and cost factors and the most acceptable strategy is chosen. A functional model is created. A list of projects and technical means is presented, and the time periods and costs required for implementation are estimated. The priority directions of work are identified.Large quantities of radioactive and toxic wastes are produced during salvaging and rehabilitation of nuclear and radiation-hazardous objects of the fleet. At salvaging enterprises, the daily hazard of toxic wastes with respect to chemical risk was hundreds and thousands of times greater than the radiation risk [1−3]. The reason is that thermal and mechanical methods were used to disassemble submarines and surface ships. Oxides, the ingredients of the materials being worked, and dust enter the air [4]. Fragments of structures and covers which are stored on the territory of the plants are formed. Process liquid media are extracted from ships at the preparatory stage. Finally, gaseous, liquid, and solid wastes are formed.Gases, aerosols, and dust enter the atmosphere without any purification. The liquid wastes are partially neutralized, purified, and burned; all other wastes are collected into storage spaces. The solid wastes are put into containers which are placed on open sites or moved to city grounds (dumps). Heavy particles of metals and their oxides and other chemical substances making up aerosols and dust settle on the territory of the plants. Rain and melt waters carry them into the adjoining marine water area. Washing and household water containing petroleum product impurities are first purified and then discharged in the water area. The territory becomes contaminated as a result of long-term storage of disassembled structures and materials, including coatings and insulation, in the open (Fig. 1).Almost all liquid wastes are hazardous. They must be reprocessed or destroyed. Individual types of greases, hydraulic liquid, freons, and chromium-containing water solutions are neither reprocessed nor destroyed. The danger of solid