Vol 119, No 6 (2016)

The influence of technological variance in the absorber arrangement on the effectiveness during burnup is studied in a one-dimensional model in the form of a homogeneous cylindrical reactor of infinite height. An analytical approach based on the theory of random functions is used. Several possible variants of the concentration fluctuations along the radius of an absorber element differing by the radial dependence of the dispersion and the degree of correlation are studied. It is shown that compared with the overall variance of the absorber content the fluctuations are of very little significance for the effectiveness of an absorber element.

A systems approach to evaluating the service life of the reinforced, prestressed, concrete, containment shell of an NPP with VVER-1000 is examined. The main steps in evaluating the technical condition and remaining service life of its structural units are described. An additional 30-year period of operation of the containment shell of the No. 1 unit of the Kalininskaya NPP and the Nos. 2 and 3 units of the Balakovo NPP is determined on the basis of these investigations.

An expression for the coefficient of radiation-stimulated diffusion of interstitial atoms, which arises in a flux of fast electrons, is obtained on the basis of a solution of Boltzmann’s equation. As a specific example, a relation for approximate evaluation of the coefficient of radiation-stimulated diffusion of interstitial atoms in a flux of fast electrons formed when fast heavy charged particles decelerate in materials is presented and analyzed.

The results of investigations of interactions in the systems UF₆–CH₃OH and UF₄–CH₃OH in the gas phase at atmospheric pressure and temperature 350–450 and 550–650°C, respectively, are presented. A new method of converting UF₆ to UF₄ and UO₂ and water-free HF via its interaction with atomic hydrogen, whose source is methanol, is proposed on the basis of these results. The fact that atomic hydrogen is obtained at moderate temperature and is chemically active for subsequent processing of UF₄ and UO₂ of the required quality and the suitability of corrosion-resistant steel and nickel for the process hardware attest that this method of conversion of depleted uranium hexafluoride holds promise.

The relation between the structure and acoustic parameters for silicon carbide/graphite composite is shown. The effect of the composition and density of the composite and the size of the structural component of silicon on the propagation velocity and damping of the longitudinal ultrasonic wave at frequency 1, 4, and 5 MHz is determined. The results obtained can serve as a basis for testing the quality of the parts in tribocoupling units.