[en] The viability of six commercial resistance thermometers is examined under reactor conditions; the sensitive element was P1-2 platinum wire of diameter 50 /mu/m. The resistances R/sub 0/ of the thermometers at 0/degree/C were 46.00/plus or minus/0.02 /OMEGA/while the ratios were R/sub 100//R/sub 0/.1.391/plus or minus/0.0007. The design and manufacturing technology have been described. The thermometers were irradiated in a VVR-M reactor. The thermometers were calibrated before and after irradiation outside the reactor by the reference-point method at temperatures of l00, 231.8, and 327.2/degree/C. 7 refs

[en] The PUCHOK-BM program was used for a thermophysical analysis of the HLP of a gas-cooled fast reactor, considering 217 rod fuel elements arranged in a triangular lattice with relative step s/d equal to 1.32, and relative distance to the wall equal to 1.33. The numbering scheme adopted for the rods and elementary cells together with curves of the energy distribution in the cassette cross section, is given. The cassette is cooled by helium with an initial pressure of 160 bar. In the calculations, the equation of state of an ideal gas and the temperature dependence of the viscosity and heat conduction of helium were used. 10 refs

[en] Moessbauer measurements have been made on the phase composition for various corrosion products in various systems in a nuclear power station, and the results are fully explicable in relation to the processes of formation and are in agreement with data obtained by other methods, in particular x-ray spectroscopy. The Moessbauer spectra were recorded with a YaGRS-4M /gamma/-resonance spectrometer. 15 refs

[en] The relationship between the critical mass velocity of hot water on a number of operating and geometrical parameters is investigated. The greatest effect on (/rho/w)/sub cr/ is exerted by the pressure and underheating of the water at the nozzle inlet. The critical mass velocity of outflow of underheated or saturated water also depends on the length of the cylindrical throat of the nozzle. It has been established that (/rho/w)/sub cr/ decreases as l/sub th/ increases. However, this effect gradually attenuates as l/sub th/ increases. The greater the underheating of the water at the nozzle inlet, the sooner the effect of l/sub th/ attenuates. Investigation of the effect of throat diameter revealed that increasing d/sub th/ from 10 to 30 mm resulted in roughly a 5-8% increase in (/rho/w)/sub cr/. The effect of the aperture angle of the diffuser turned out to be negligible, at least for 3/less than equivalent to//alpha//less than equivalent to/180/degree/ and l/sub th//d/sub th//greater than equivalent to/1.5

[en] Surveys have been published of data obtained in experiments with outgassed water and with water in which the gas concentration either was not measured at all or else was measured after outgassing with an inadequate accuracy. It is desirable to estimate the size of the difference between the critical heat loadings calculated and the values found by experiment with nearly zero dissolved gas. For this purpose a system is described having a gas and steam volume compensation system for the coolant, as well as a system for simulating and monitoring the dissolved gas. The error in determining the dissolved gas concentration was not more than /plus or minus/5%. 3 refs

[en] The results are described of an investigation of another concept, which makes it possible to use metal fuel in the core of a fast reactor under temperature conditions close to previously employed conditions. It follows that fast reactors, in which oxide and metal fuels are used in combination, have an increased specific load and an increased breeding coefficient relative to fast reactors with oxide fuel; this reactor type allows faster rates in the development of the entire nuclear energy generation balanced in regard to fuel. The combined use of mixed oxide and metal fuels requires additional research on the possible operation of fuel elements in such a core

[en] Values for the ratio of the /sup 239/Pu and /sup 235/U fission cross sections over the energy intervals are in good agreement with Carlson's data. Carlson's data were normalized by the threshold method and also to Lemmel's data, which in turn were normalized to the thermal region. The totality of the data listed on the /sup 235/U fission cross section, Carlson's data, and our results for the ratio of the fission cross sections are inconsistent with the average energy dependence of /sigma/sub //f (/sup 239/Pu) reported in recent papers by Gwin, Gayther, and Ryabov

[en] Inorganic compounds of lithium, primarily the thermally stable Li/sub 2/O, LiAlO/sub 2/, Li/sub 2/SiO/sub 3/, and Li/sub 4/SiO/sub 4/, are now considered as starting materials for the production of tritium in a thermonuclear reactor. In view of this, this article analyzes the influence of radiation on the indicated lithium compounds and evaluates the possibilities of reproduction of tritium in the blanket of a thermonuclear reactor. 8 refs

[en] The calculated sensitivity coefficients show that in a hybrid reactor the greatest influence on the principal functionals is exerted by the secondary neutron spectra of the reactions /sup 238/U(n, 2n), /sup 23B/U(n, n/prime/) cont, and Fe(n, n/prime/) cont, for which the contribution to the fission rate in /sup 238/U and, therefore, in neutron multiplication per source neutron, may be considerable. The indeterminacy of the functionals, owing to the 15-20% inaccuracy of the spectra, is estimated for the hybrid reactor model studied to be 3-4.5% for the fission rate and 2-2.5% for the tritium yield

[en] A method has been developed for calculating the stability of a power reactor with any stationary power distribution; tables have been formulated for the values of the parameters that can be used to determine the instability buildup period for the radial and azimuthal power distribution. A dip in the steady-state neutron distribution at the center of the core has an appreciable effect on the instability buildup period, e.g., a 30% dip at the center of the core reduces the period by about a factor 1.5. This method can be used with the method of measuring the instability period in identifying the individual dynamic parameters of a power reactor. 3 refs