Izvestiya vuzov. Yadernaya Energetika

The peer-reviewed scientific and technology journal. ISSN: 0204-3327

On high level waste immobilization in y-al garnet-base cermet matrix under SHS conditions

4/04/2015 2015 - #01 Fuel cycle and nuclear waste management

Konovalov E.E. Lastov A.I. Nerozin N.A.

DOI: https://doi.org/10.26583/npe.2015.1.12

UDC: 621.039.736

A method of high-level radioactive waste (HLRAW) radionuclides immobilization in a long-lasting Y-Al garnet matrix has been developed for their ultimate isolation from the environment. This matrix material is notable for endurance and high chemical resistance to natural media. Model systems containing Ce, Nd, Sm, Zr, Mo, 238U, and 241Am as simulators of HLRAW radionuclides were used in the work. An energy-saving technology of self-propagating high-temperature synthesis (SHS) with good technical, economical and environmental performance was applied for synthesizing the matrix material with the radionuclides-simulators fixed in the garnet structure. The results of X-ray phase analysis proved the formation of Y-Al garnet with strong inclusion of the simulating elements in its structure.

The produced synthetic mineral-like matrices are notable for high water-resistance. This property is confirmed by a low rate of 241Am leaching that is equal to 10–5 – 10–6 g/m2⋅day. A high strength of 241Am fixation in the Y-Al garnet structure is supplemented with a low value of americium carry-over at high temperatures of the synthesis that is caused by a short duration of the SHS.

It is recommended to apply the proposed novel method of HLRAW immobilization for developing a technology of ultimate processing of spent nuclear fuels of NPPs.

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high level waste actinides immobilization self-extending high-temperature synthesis matrix materials