[en] A mathematical model for numerical computation of stressed-deformed stae in a rod cylindrical fuel element is developed. The model is based on preliminary discretization of the design scheme and linearization of radial parameters as radius functions. The formulation generality enables to calculate strength parameter kinetics in any circular cylindrical fuel element (e.g. annular fuel element; solid or tubular core; ceramic, metallic or dispersion fuel) for arbitrary transient operating conditions and taking into account all possible loading factors. The method is realized in the KONDOR programm (FORTRAN, ES-1061 computer). An example illustrating computation of stress kinetics in a fast reactor fuel element during transient operation is given

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No abstract available

[en] A possible accident in a fast reactor core when a pressure pulse (a hydrodynamic impact in a coolant) accurs as a result of heat transfer crisis in a fuel assembly (FA) is considered. The possibility of estimation of the degree of accident propagation along the core using numerical simulation of kinetics of plasto-elastic stressed-deformed state of FAs surrounding the accidental one is shown. The FEMINA program complex designed for the solution of nonlinear and/or nonstationary problems of thermomechanics in the arbitrary plane configuration by the finite element method is briefly described. The results of testing calculation are presented. 4 refs.; 7 figs

[en] Results of mathematical simulation of major strains, occuring under the swelling of hollow cylindrical column of a fuel rod, placed into hard coating are presented. Strain-stress state of fissile material, its free swelling being described in terms of spheric gas pore model, is considered on the basis of the finite strain theory. A system of ordinary differential equations is derived, describing considerable form change of the internal hollow of cylinder out of fissile material under its constrained swelling in hard coating. Results of numeric integration and analytical solution of the derived differential equations for a wide spectrum of the model parameter values are presented

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No abstract available

[en] An algorithm for finite-element method calculations of generalized plane deformation allowing one to simulate stress-deformed state of reactor core elements at considerable radiation deformation of materials is given. For the elastic-plastic task the joining of methods of the elastic variable parameters with numerical integration of the system of linear differential equations, which increases stability of the numerical integration and conserve capability of geometric nonlinearity account, is suggested. 4 refs.; 2 figs

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[en] Analysis of TOPAZ thermionic reactor moderator block have been carried out to study strength under unhomogenous deformation. The moderator block works under unhomogenous and unsteady temperature and neutron fields, which cause swelling of moderator material (zirconium hydride). One of the main demand which moderator block of the reactor must satisfy is cracking absence during lifetime. From mathematical point of view the simulation of moderator material behavior is the solution of boundary-value problem of thermomechanics (with receiving temperature, displacement, stress and strain fields). For solution of non-linear and (or) unsteady boundary-value thermomechanics problem was made a two-dimensional finite-element code FEMINA. The problem is solved with consideration of swelling and creep-strain of the zirconium hydride under unhomogenous and displacement, stress and strain fields is shown. Quantitative strength estimates of the moderator block have been made. (author)