National Research Nuclear University “MEPhI” (Moscow Engineering Physics Institute), Moscow, Russia:

S. N. Nikitin, Engineer of Applied-Research Laboratory 709, e-mail: mephi200809@yandex.ru
B. A. Tarasov, Engineer of Applied-Research Laboratory 709

D. P. Shornikov, Senior Researcher of Applied-Research Laboratory 709
V. G. Baranov, Senior Lecturer of a Chair “Physical Problems of Material Science”

Research reactors are operated at rather high power densities of core energy release of and high burnup, which is connected with necessity of neutron flux density increasing and operating cost reduction. High-density dispersion uranium alloy compositions in aluminum matrix are more applicable for exploitation as fuel rod for the possibility of transition to low-enriched fuel in existing core geometries without significant reduction of neutron flux density. The main constraint to application of this composition is interaction between U – Mo granules and aluminum matrix at high burnout levels. Interaction leads to further swelling of fuel rods, reduction of matrix thermal conductivity, increase of fuel rod center temperature, formation of intermetallic compounds, through porosity and fuel rod failure. Interaction with aluminum leads to restrictions on operating conditions of U – Mo fuel in reactor, which requires the search for new alternatives. Compositions with metallic particles of uranium-molybdenum alloys in aluminum matrix, containing from 2 to 8% (wt.) of Be, are considered in this work as promising fuel compositions of dispersion-type fuel rods. The main objective of the work is experimental determination of effect of aluminum matrix beryllium doping on its kinetics of diffusion interaction with metallic uranium-molybdenum alloys. There was defined a linear decrease in the rate of interaction with increasing of beryllium content to 8% (wt.) in aluminum alloy. Comparison with other aluminum matrix alloys showed the advantage of both thermal, mechanical properties, and compatibility with uranium-molybdenum alloys.

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