No abstract available

[en] Electric conductivity mechanism of mineral insulation of cables and emissive radiation detectors under irradiation conditions and beyond them has been considered. A general expression for electric conductivity of mineral insulation under irradiation has been obtained on the base of a zone model of solid with traps. Coefficients of this general expression have been calculated by means of combined statistical processing of experimental data by soviet and foreign investigators of cable magnesia insulation resistance. An analogous general analytical expression has been obtained for an emissive neutron detector having magnesia insulation and silver emitter. Errors have been estimated when using obtained general analytical expressions; coefficients errors have been calculated in this expressions by the Monte Carlo method. The above method for the processing of experimental and calculational results permits obtaining the general analytical expression to present all the experimental and calculational information of a value under consideration in obvious and visible form. Relations obtained for cables and emissive detectors may be used in developing new designs of emissive detectors and ionization chambers

[en] Controlling the distribution of the power production in an RBMK is an optimization problem, whose goal function is to minimize the overall power nonuniformity coefficient K_v or the linear power of the fuel elements for a fixed reactor power. In the process of controlling the power distribution, the reactor operator has available qualitative information on the deviation of the current power distribution from the specified value in the form of over- and undershoot signals, which are calculated by the information-processing system from signals from detectors in the reactor and which are displayed on a graphic panel. In controlling the power distribution he observes several limits: (1) he does not exceed the allowable power of a fuel-element bundle; (2) he maintains the margin control for the linear automatic control rods or automatic control rods within a given range; (3) he moves no more than four control rods; (4) he does not lower the minimum allowable research against (a) heat-transfer burnout, (b) the linear power in the fuel elements, and (c) the temperature of the graphite cladding; and (5) he pays attention to the emergency settings of signals of in-reactor detectors and lateral ionization chambers. In view of the complexity of th problem of rigorously minimizing K_v, a convolution of separate effectiveness criteria is used both in practice and in methods research. The most complex is the problem of finding the weight factors in this convolution. A similar approach is implemented in the open-quotes Reactor Operator Advisorclose quotes program, which is designed to automate the optimization of parameter distributions in an RBMK core. A method was developed for combining the recommendations of different operators among themselves and the recommendations of the operator computer model

[en] Short communication

[en] The reactor power distribution optimization problem is solved for the case of the RBMK-1000 reactor. The algorithm is written in terms of the linear programming method. The algorithm rests on two assumptions: 1) the relative power change of each fuel assembly is a linear function of reactivity increment caused by displacement of a regulating rod; 2) the change is an additive value. The algorithm is written in ALGOL for the BESM-6 computer. The optimum reactivity gain for the RBMK reactor has proved to equal the reactivity of 35-40 control rods. The results obtained confirm the validity of the assumptions. It is noted that the total computation time on the BESM-6 can be reduced to 20 min

[en] Presented is the algorithm for extremal control of power distribution in a power reactor with the help of digital computer (DC). In algorithm realized is step-by-step (pulse) retrieval of the extremum of aim functions with self-turning of regulating parameters minimizing time expenses for search of optimal state. The algorithm does not require usaae of reactor model for regulating power distribution under operation conditions of NPP, thats why calculation time obtained with the help of DC is comparatively small and may be less than the regulating rod displacement time. Presented are the results of minimization of power distribution variation factor along the core radius on the detailed adiabatic model of RBMK-1000 reactor

No abstract available

[en] The efficiency of the power distribution on-line control in reactors, depending on the control accuracy taking, into account the reactor core thermochemical reliability characteristics is analyzed using the normal law of random variable distribution

[en] An analysis of theoretical and experimental work on metastable thin-film systems having elevated superconductance transition temperatures (Tsub(k)) has been given. Initially, possible means of improving the semiconductor Tsub(k) temperature are examined, and subsequently non-stable metallic and semiconductor films produced by the condensation at helium temperatures, by low-temperature ion implantation of light-weight elements, and also A15 structure superconducting alloy films are considered. The principle attention is centered on the interpretation of factors causing Tsub(k) increments in such films. The authors have examined all the possibilities of the metastable thin-film systems, where the activation of electron-phonon interaction results in increased Tsub(k). A conclusion is made that high temperature superconductance correlates with various nonstabilities

[en] A physical calculation approximation of discrete measurements of power disturbtion in a nuclear reactor is described. The approximation involves the least square method in adjusting the initial reactor physical constants. The results of the approximation for the uranium-graphite reactor are presented. The approximation results are shown to be sufficiently stable with respect to random errors of distribution measurements; the approximation mean square error does not exceed 3-4%