[en] The thermally instable solution of a material intended for gelation and of hexamethylene tetramine and/or urea is dispersed in a heated dispersion medium immiscible with water. Gel particles formed are separated from the dispersion medium, incorporated in oil at a temperature of 1O to 60 degC and cooled in this bath to room temperature. The spherical gel particles formed show increased resistant to cracking and destruction in further production operations. (M.S.)

[en] A jet is described which is suitable for the preparation of sorbents, catalysts and nuclear fuels in form of spherical particles of equal size. The jet comprises no moving parts and allows to produce particles in sizes from 0.1 to 1.0 mm. The advantage of the particles thus produced is, e.g., a reduction in the dust level from the production of nuclear fuels and the possibility of remote control of the process. (E.S.)

[en] The course and the results of measurement are described in stress analysis of a valve controlling the inlet pressure of the primary coolant circuit of the A-1 nuclear power plant. The analysis comprised the measurements of both static and dynamic strength, including vibrations of the valve body and the appropriate piping as well as coolant pressure pulsations. Also determined were the course of excitation forces, basic torsional and bending frequencies and the resonance valve frequency under simulated main operating loads. (J.K.)

[en] In CMEA member countries, seismic stability of fittings for nuclear power plants is assessed following VTP 87 regulations. These regulations involve a classification of fittings and procedures for the evaluation of their seismic stability by calculation and by experiment. In the first stage, the dynamic characteristics are established, and in the second stage, the strength, leakproofness and working ability of the fitting are checked on a vibration stand. The fitting is fixed to the base plate behind the couplings by means of consoles. The vibrations are excited predominantly in two directions by means of a Bruel and Kjaer device, and the response is measured with a portable acceleration sensor supplied by the same manufacturer. The evaluation of the earthquake resistance by calculation comprises largely two steps: calculation of the lowest eigenfrequency f₁ and quasistatic calculation for f₁>20Hz. (Z.M.). 8 figs., 5 tabs., 8 refs

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