Radionuclide Sorbents for Deactivation
Development of Technology for Production and Application of Radionuclide Sorbents Basing on Man-Caused Wastes after Dressing Apatite-Nepheline Ores
Tech Area / Field
- ENV-RED/Remediation and Decontamination/Environment
8 Project completed
Senior Project Manager
Genisaretskaya S V
VNIIEF, Russia, N. Novgorod reg., Sarov
- Russian Academy of Sciences / Kola Science Centre / Tananaev Institute of Chemistry and Technology of Rate Elements and Mineral Raw Materials, Russia, Murmansk reg., Apatity
- Sandia National Laboratories, USA, NM, Albuquerque
Project summaryOperation of NPPs, nuclear power facilities of civil and military purposes is accompanied by the formation of environmentally hazardous radioactive waste. For this reason, of great importance are the problems of storage and reprocessing of spent nuclear fuel (SNF), as well as the problems of reprocessing and immobilization of liquid radioactive waste (LRAW) for further safe storage. The problem of waste management and reprocessing attracts keen interest, since they are potentially hazardous for the ecosphere. The current tendencies in handling radioactive wastes are aimed at the minimization of RAW by concentration and compaction.
The methods based on selective sorption of radionuclides using natural and synthetic sorbents should be considered as the promising ways of radioactive waste reprocessing. As sorbents one can use natural and synthetic zeolites, ionited rubbers, fiber materials, hydroxides, and phosphates of transition metals.
Sorbents are, as a rule, rather expensive materials. So, their use is rather costly. From this point of view, of certain interest are nepheline-based composite sorbents, which are produced using technogenic wastes after dressing apatite-nepheline ores. Even more so, the cost of these compositions is about an order less than cost of the existing synthetic sorbents based on aluminum sulfate and the others.
The suggested sorbents contain hydrated hydroxide and phosphate of titanium, calcium phosphate, and amorphous silica. This composition allows reaching the maximum chemical inertness and thermal stability of final product. Thus, the protective “barrier” is formed for storage of it in future.
The specific structure of the composition causes the universal character of their sorptive capacities and allows purifying liquid discharge of both radioactive pollutions and non-ferrous metals and heavy metals.
According to data of KNPP Research Laboratory, sorptive capacity of the experimental samples of sorbents is the following:
- 1.5÷1.8 mg·eq/g – for radioactive elements (with recalculation for Cs137);
- ~ 2 mg·eq/g - for non-ferrous metals and heavy metals (Co, Ni, Cr, etc.).
The purification extent is predicted as more than 90% at the initial concentration of metals equal to ~ 10-3 g/l.
In order to develop an industrial technology for the production and application of radionuclide sorbents based on technogenic apatite-nepheline ore processing waste, the following steps need to be taken:
To study the process of synthesis of synthetic mineral composition sorbents using concentrates and technogenic apatite-nepheline ore processing waste;
To study the sorption properties of sorbent considering a wide range of radioactive elements, including transuranium elements;
To develop methods for effective application of sorbents at various plants for manufacturing and storage of radioactive materials.
The Project proposed will provide a real opportunity for setting up commercial production of inexpensive and effective sorbent, and for developing a technology for using silica-titanium sorbents at plants having radioactive wastes and salts of heavy metals.
Preliminary designs of a mobile and fixed stations to purify different kinds of contaminated water will be suggested.
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