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Immobilization of Alpha-Active Wastes in Porous Composites

#2506


The Exploration of the Immobilization Method of Alpha-Active Wastes in Chemically Stable Porous Composites

Tech Area / Field

  • ENV-RWT/Radioactive Waste Treatment/Environment

Status
3 Approved without Funding

Registration date
30.04.2002

Leading Institute
A.N.Frumkin Institute of Physical Chemistry and Electrochemistry, Russia, Moscow

Supporting institutes

  • All-Russian Scientific Research Institute of Non-Organic Materials named after A. Bochvar, Russia, Moscow\nSiberian Chemical Combine, Russia, Tomsk reg., Seversk

Collaborators

  • Sandia National Laboratories, USA, NM, Albuquerque\nCNRS / Universite Paris-Nord / Laboratoire d'Ingenierie des Materiaux et des Hautes Pressions, France, Villetaneuse

Project summary

The most dangerous fraction radioactive wastes (RW) are long-live actinides. Recently it is recognized that the most reliable immobilization methods of high-level radioactive wastes (HRW) are they’re fixing in glass-like, basalt-like and ceramic matrixes. One of methods of neutralization of HRW in the future can become their nuclear burning at the irradiation by neutrons in reactors or on accelerators (transmutation). Therefore the immobilization blocks and transmutation target should, first, be suitable for a safe long storage within ~103 years - to be steady chemically, thermally and in relation to leeching by earth waters. Secondly, it is necessary, that these compositions met the requirements of radiating stability not only in a storage time, but also in powerful fields of radiation of devices-burners, that is would have high nuclear inertness, low cross section of neutrons. Besides for achievement of the high degree of burning out of actinides the chemical form of targets should provide their stability to swelling of fuel particles and opportunity of the removal of gaseous of products of pision. It can be achieved in the case of use as the matrix-carrier the high-porous materials from the refractory compounds of transition metals. To all specified requirements can satisfy porous matrixes from compounds of zirconium, for example, carbide, dioxide, and also compounds of other metals; porous metal matrixes; porous ceramic composites.

The work will be carried out in the following directions:

– research of synthesis methods of various porous matrix compositions, in particular, the obtaining of carbide and oxycarbide matrixes by the method of the carbothermical reduction of the oxides of transition metals;


– study of the ways of HRW inclusion in porous matrixes, methods of the maximal saturation of matrixes by the difficulty soluble chemically, thermally and radiation stable forms and compounds of HRW radionuclides;
– study of the final closing ways of surface porosity after saturation of matrix by radioactive wastes and its calcination.

Physical-chemical and operational properties of matrixes with entered radioactive wastes and, above all, the leaching rate of radioactive isotopes at the contact of matrix with water at various temperatures also will be investigated. The optimum structures of matrixes and methods of their synthesis will be chosen. Bases of technology immobilization of the HRW in investigated matrixes, and obtaining the targets for transmutation of actinides also will be developed.


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