[en] The features and the principle of operation of an integral-differential amplitude-to-time converter are described and its schematic diagram is presented. With the purpose of increasing the conversion factor thermal stability in the converter circuit the following elements are used: saturated transistor keys with a common emitter, bridge circuit of shaper switch-on, and current stabilizer with a negative temperature coefficiency of the current. The results of the experimental studies have shown that the amplitude-to-time convertter based on transistors KT306B and diodes D220 has the following characteristics: the dynamical range of amplitudes of the converted pulses, 0.06 - 4.2 B; the regulated conversion factor, 3-15 musec/B; the minimal duration of input pulses, 150 nsec; the differential nonlinearity not greater than 1.6%. In the temperature range from 20 to 80 deg C the best thermal stability of the conversion factor is ensured at currents from 5 to 10 mu A and does not exceed 0.028%/deg

[en] Results are presented from an experimental study of the hydraulic resistance of peripheral cells of a rod assembly in a hexagonal casing with smooth- and rough-surfaced rods. The study was conducted in the Reynolds number range 5000-4000. The results obtained show the presence of important features in the flow structure in the peripheral cells which have an appreciable effect on the shear stress distribution about the perimeter of the cells. It is suggested that the effect of structural parameters of the rod assembly be studied in a broader range of Reynolds numbers. This should make it possible to refine the analysis of different designs of gas-cooled-reactor fuel elements

[en] Numerical solution of the Stephen problem by the strained coordinate method is presented for an one-dimensional sphere. Differential formulae of heat fluxes from moving interfaces do not take into account volume heat capacities of the front nodes. Calculations, carried out according to these balanced formulae, as well as according to those usually used, have shown that the balanced formulae permit to reduce approximately by an order the number of nodes on the sphere radius, if similar accuracy of heat balance of the whole process of melting or crystallization is observed. 2 refs.; 1 fig

[en] One of the main directions in the management of high-level radioactive wastes is the development of specialized reactors for transmutation with maximum support coefficients for the existing power reactor. The developments have shown that it is more expetitious to design the reactor for actinide transmutation and for fission products separately. For the above purposes, the FBR type fast neutron reactor and FMF type fast reactor with melted fuel were considered

[en] The character of nickel (2) and cadmium hydroxide interaction in discharged cadmium electrode and the nature of nickel and cadmium phase interaction in discharged electrode are studied. The necessary condition of activating and stabilizing effect of nickel (2) hydroxide addition is its chemical interaction with an active mass of cadmium electrode resulting in formation of nonequilibrium solid solution of substitution between nickel (2) and cadmium hydroxides, and at charging-nonequilibrium solid solution of nickel and cadmium introduction. The formed solid solutions are unstable and decompose when electrodes are kept in alkali

[en] Problems of centrifugal heat transfer intensification are considered as applied to channels of nuclear reactors. Experiments on intensification of convective heat transfer, surface subcooled boiling heat transfer and bulk boiling are described. Equations and properties of swirling cylindrical flows are presented. Ways of optimization of swirl generator designs are proposed

[en] The modified stimulated photon echo is proposed as a method for the investigation of elastic collisions of excited atoms with non-excited foreign gas atoms, which induce the redistribution of the excited atoms in Zeeman sublevels. It is shown that the proper choice of mutual orientation of the exciting-light polarisation vectors makes it possible to determine the relaxation times for the population, orientation and alignment of a resonant level. It is found that the formulae, derived in the limit of exciting-pulse small areas, are the most attractive for spectroscopic purposes, as in this case the polarisation properties of the modified stimulated photon echo do not depend on the exciting-pulse shapes, nor on their areas. (author)

[en] Results are presented from an experimental study of the hydraulic resistance of peripheral cells of a rod assembly in a hexagonal casing with smooth- and rough-surfaced rods. The study was conducted in the Reynolds number range 5000--40000

[en] The draw backs of the fuel cycle of new fast reactors are described. Included are: necessity to produce fuel elements; fuel, compulsory chemical re-processing; radioctive products accumulation within the fuel element cladding when those radioactive products are in the reactor with a potential to release under a core meltdown. Design concepts of the FBR type to overcome the above are discussed

[en] The polarization properties of the photon echo for optically allowed transitions with arbitrary values of the angular momenta and with an arbitrary correlation between the durations of the exciting light pulses and the reversible Doppler relaxation time are determined in the small area limit of the exciting pulses. (orig.)