[en] The experimental and calculational investigations of radiation heating in fissionableless materials used in thermal heterogeneous reactor channels is out. The character of the heating radial distribution in the zone of an axial reflector is determined. The technique for determining energy release during ν radiation absorption in Be, Zr, Al and Fe based on the Gray theory is developed. The mesurements are performed at the critical assembly representing a strongly heterogeneous system the core of which consists of 108 channels in a water moderator and surrounded by a radial reflector. An ionization chamber of special construction was used for measurements. Calculation of heating is performed according to the QUANTA program which realizes the solution of stationary equation of ν radiation transport in heterogeneous medium by the Monte Carlo method. It is shown that ν radiation flux over the assembly radius in all cross sections by the fuel height and over the height of the assembly for all channels can be described by the same distribution within the limits of 10%. The comparison of experimental and calculational absolute values shows the presence of their systematic divergence within the limits of 30%. It is concluded that the data obtained permit to perform correction of the methods and programs for heating calculation and have a practical advantages when solving the problems of heat release profiling in the reactor core

[en] The results of studying the neutron-physical characteristics of special nuclear reactors for neutron radiography are given. Experiments have been performed at the critical assembly with graphite and graphite-beryllium reflectors simulating the core of the ARGUS experimental reactor. The efficiency of absorbing rods and reactivity effects determining critical mass and reactor core charge as well as spatial distributions of thermal, resonance and fast neutron fluxes in reflectors are measured. In order to test and improve the calculational techniques the comparison of calculational and experimental data is made. The conclusion is made that the obtained results can be used for forecasting the parameters of small-size reactor cores with hydrogen-containing reflectors

[en] Using calculation-experimental way, the possibility has been considered to employ, in experiments with critical assemblies, instead of high-temperature gas-cooled reactor fuel elements with microparticles, model fuel elements with cores of homogeneous mixture of uranium dioxide and fluoroplastic-4 (polytetrafluoroethylene). Comparative analysis of neutron-physical characteristics of fuel elements with microparticles, dispersed in graphite matrix, and those of model fuel elements is carried out. Results are presented of experimental evaluations of macroscopic cross sections of the neutron interaction with fluoroplastic-4 and data testing the uranium dioxide-fluoroplastic-4 composition samples for radiation stability and moisture absorption. The conclusion is drawn that fluoroplastic matrix substitution for graphite matrix does not affect neutron-physical parameters of the fuel elements. The change in the thermal neutron fission cross section does not exceed 0.6%. Mechanical properties of the uranium dioxide-fluoroplastic-4 composition meet the requirements for fuel elements being simulated

No abstract available

[en] To enhance the efficiency of nuclear materials control and accounting a complex of weight sensors and a complex of 'smart shelves' were put into operation at one of the facilities of the RSC 'Kurchatovskiy Institute'. The weight sensors and 'smart shelves' equipment designed in ORNL provide for a continuous, remote measuring of weight of the controlled items and their constant inventory valuation. After inspection, testing, adjustment and finishing of the used software the both complexes were built up at one of the nuclear material depositories. The complexes control more than 20 kg of uranium-containing nuclear material with enrichment of 90% by U-235, in form of small non-identified components placed in specific casks. Application of the weight sensor complex, combined with the complex of 'smart shelves', provides for on-line detection of the clandestine, long-term removal of nuclear material in small portions