A. V. Afanas’ev

Wear dynamics of fragments in the lower part of a fuel assembly with unattached rods

The dynamic characteristics and wear of unattached fuel rods in the lower supporting lattice are investigated. The vibrational eigenfrequencies and dynamic rigidity of the fuel rods in different configurations are determined. The vibrational wear at contact between the fuel rods and the spacing elements is studied.

Seismic tests of fuel assemblies

Seismic tests of full-scale mockups of fuel assemblies from the VVER-1000 reactor permit the determination of the transfer characteristics between the stimulus (acceleration of the supports) and the response of the fuel assemblies. No resonant responses of the fuel assemblies to seismic loads are observed.

Pile dynamics in coolant flux

Intrinsic and forced vibrations of a reactor pile in standing water and in coolant flux are investigated. The eigenfrequencies and damping factors of the intrinsic vibrations and the parameters of forced vibrations of the fuel rods are determined. The influence of the auxiliary spacers on fuel-rod vibrations is discussed.

Friction of fuel-rod casings and spacers in the pile of VVER reactors

Frictional tests of fuel-rod casings and spacing cells are conducted in various conditions. The frictional coefficients are determined for different loads. The influence of factors such as vibration, the contact load, the sample speed, the atmosphere, and the temperature is considered.

Dynamic characteristics of the mockup of the fuel assembly in coolant flow

During exploitation, fuel assemblies are subjected to vibration loads caused by vibrations of intracase devices, pressure pulsations, acoustic waves, and turbulent flow of the coolant. Vibrations of the fuel assembly can be the cause of damage to its details, particularly, fuel elements and spacer lattices, because of their wear. Therefore, one requirement for the project of the fuel assembly of AES-2006 reactor installations is vibration strength and resistance throughout the service life of the fuel assembly in the reactor. The vibration strength and fuel assembly strength are substantiated by computational-experimental methods using the results of the experimental modal analysis of the full-scale mockup for verification.

Resistance to fretting corrosion of fuel rods in a VVER-440 water-moderated reactor in contact with spacers

The wear resistance of fuel assemblies in the VVER-440 water-moderated reactor is investigated, with small fuel-rod diameter. The experimental apparatus, the model of the fuel rods, and the similarity conditions are described; the possibility of applying the experimental results to regular fuel rods is noted.

Drop strength of the fuel assembly in a nuclear power plant

The possible structural deformation of the fuel assembly in a nuclear power plant when dropped during transportation or other operations is considered. The consequences of such damage are studied.

Friction and wear of fuel assemblies in water-moderated reactors

Static and dynamic processes that involve frictional forces are experimentally studied. The frictional forces affect the stress of the fuel assembly in all stages of the life cycle.

Friction of fuel-rod casings and spacing cells in the pile of a water-cooled, water-moderated reactor

Fuel-rod casings and spacing cells are subjected to frictional tests, with variation in the technological and operational factors.

Resistance to fretting corrosion of VVER-440 fuel elements

The methods and results of research to substantiate the wear resistance of VVER-440 fuel assemblies with smaller nominal fuel-element diameters are shown. The results of tests of the fuel elements of VER-1000 fuel assemblies with zirconium spacer grids for fretting corrosion were used for substantiation. The test bench, the test model of the fuel element, the conditions of similarity, and the transferability of the results of experimental tests to standard fuel elements are described. It is shown that spent fuel elements with smaller diameters have significant wear resistance in contact with spacer grids.