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Safe Uranium Waste Storage

#1361


Development of Technology for Fire and Explosion Safe Storage of Wastes from Industrial Processing of Metallic Uranium

Tech Area / Field

  • ENV-WDS/Waste Disposal/Environment
  • ENV-RWT/Radioactive Waste Treatment/Environment

Status
3 Approved without Funding

Registration date
25.09.1998

Leading Institute
VNIITF, Russia, Chelyabinsk reg., Snezhinsk

Supporting institutes

  • All-Russian Scientific Research Institute of Non-Organic Materials named after A. Bochvar, Russia, Moscow\nUral State Technical University, Russia, Sverdlovsk reg., Ekaterinburg

Project summary

Priority directions of the development of energy-saving technologies in the field of mechanical reprocessing of metallic materials are the following: first of all, increasing the efficiency of primary use of parts (decrease of a portion of reusable losses of material falling within the wastes of reprocessing), secondly, increase of efficiency of secondary use of wastes (decrease of a portion of material losses at the stage of preparation and performance of metallurgical reprocessing of wastes).

Decrease off a portion of reusable losses of material is provided by the technology of reprocessing including optimization of dimensions, configuration of parts and regimes of cutting. Decrease of a portion of irreversible losses of material is provided by a technology of waste recovery including collection of shaving, compactization, storage, transportation and metallurgical reprocessing.

One of the problems of handling of chemically active wastes of uranium-based alloys is the storage in the conditions of metal-reprocessing production, preparation and transportation of shaving to the sites of metallurgical reprocessing. This is related to the fact that in order to provide optimum regimes off operation of cutting instrument in the process of cutting, lubricating and cooling liquids (LCL) are used on the basis of water solutions. Before compactization, shaving if dried by well known methods, but the content of residual moisture in compacts can reach 0.1 % mass proportion. In chemical system “uranium-hydrogen-water-oxygen”, several interdependent reactions can run, whose depth and direction depend not only on the state of surface of uranium alloys (the degree of mechanical purity, chemical state, presence and nature of technological or sanitary coatings), but on the state of gas medium, temperature and pressure. The majority of investigators underline several main reactions of oxidation and hydrogenation running in mentioned system. In the course of storage or transportation to the sites of metallurgical reprocessing of shaving, fir- and explosion-hazardous substances can be formed (first, hydrogen, and then hydrogen-based pyrophoric hydride of uranium) that may cause technogenic accident.

Currently, there are several directions of handling of chemically active shaving of uranium-based alloys:


oxidation of compacts of shaving (as a rule, by air or water vapors) up to uranium oxides of various composition, compactization and handling of fir- and explosion-proof forms of wastes;
impregnation of compacts of uranium shaving by hydrophobic mineral oil preventing from hydrogen formation, and handling of wastes according to the norms of fire hazard for petroleum products;
preservation of shaving compacts in controlled gas medium and providing fire- and explosion-proof storage and transportation.

The first direction has perspectives, if the wastes of reprocessing will be sued in the form of oxide systems, as far as in this case, metallic alloys obtaining by metallurgical reduction of oxides will be the most expensive. Disadvantage of this direction is the necessity of chemical reprocessing of shaving compacts just in the conditions of metallurgical production, i.e. the presence or establishment of thermal chemical sections.

The second way is attractive because it is simple and convenient in the terms of handling of shaving compacts in the conditions of metal-treatment production, but the preparation and performance of metallurgical reprocessing of uranium shaving is more complicated. At the stage of preparation, it is necessary to wash away mineral oil by organic solvents, and then to purify contaminated solvents and of course recovery of low active wastes (LAW).

And only the third way permits to minimize the costs of metal-treatment production as well as to minimize the preparation for metallurgical casting of uranium alloys out of shaving compacts.

In the frames of this project, it is proposed to develop cheap technology of gas inhibition of fire- and explosion-proof storage and transportation of compacts of uranium shaving not requiring deficient (or expensive) reagents and special preparation for metallurgical reprocessing of compacts of uranium shaving.


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