RESULTS OF COMPUTATIONS OF k_эф ELEMENTARY CELLS IN WWR-440 AND WWR-1000 REACTORS

V.P. Gorelov, A.N. Grebennikov, A.K. Zhytnik, T.L. Kostenko, S.V. Mzhachikh, G.G. Farafontov
VANT. Ser.: Mat. Mod. Fiz. Proc. 1997. No 3. P. 3-9.

      The results of computations of k_эф elementary cells of triangular fuel element lattice in reactors WWR-440 AND WWR-1000 obtained using the group method and Monte-Karlo method are given. The influence of the technique of accounting resonance and heterogeneous effects, chemical bond in a coolant and boundary condition selection on the results of group computations is studied.

A.N. Grebennikov, N.A. Krut´ko, S.V. Mzhachikh
VANT. Ser.: Mat. Mod. Fiz. Proc. 1997. No 3. P. 10-17.

      The paper considers the principal conceptions of the universal programm shell TSS, namely: problem setting, data structure and representation, interactive user interface. System aspects of the TSS shell development as a resident data server in MS-DOS environment for 32-bit Fortran-77 applications of the i486 processors protected mode are described.

M.V. Khabibullin
VANT. Ser.: Mat. Mod. Fiz. Proc. 1997. No 3. P. 18-24.

      The method of numerical simulation is proposed which in a wide range of impact velocities allows to predict the results of a projectile interaction with a plate shielded target of a finite thickness. Comparison of calculated and experimental results shows that the represented model of debris flux gives a satisfied agreement for main damage parameters of the shielded structure.

V.A. Andronov, S.A. Bel´kov, G.V. Dolgoleva, L.S. Mkhitaryan, V.V. Nikiforov, A.N. Razin
VANT. Ser.: Mat. Mod. Fiz. Proc. 1997. No 3. P. 25-32.

      The description of the numerical turbulent mixing model generalized for the case of non-equilibrium, non-stationary multicomponent plasma is given; this model implemented within one-dimensional radiation hydrodynamics code SND-TUR. The influence of effects related to spectral x-ray radiation transfer on the dynamics of a multilayer target motion and turbulent mixing zone development is being studied.
      It is shown to what extent experiments with gases under usual conditions and computation techniques developed on their base are suitable for describing experiments with laser shell acceleration.

B.L. Voronin, A.A. Kazarin, S.I. Skrypnik
VANT. Ser.: Mat. Mod. Fiz. Proc. 1997. No 3. P. 33-38.

      Parallel algorithms for solving 3-D hydrodynamics problems with account of heat conduction on shared memory computer systems are described. The brief description of differential equations for spatial movement of a heat conducting gas and the technique for solving them is given. Three ways of parallel computation arrangement are considered.
      Results are given for numerical experiments on computing 3-D hydrodynamics problems with heat conduction in the parallel mode on 10-processor computer system MPS “Elbrus-2”. The efficiency of the developed parallelization algorithms depending on a number of computational points and a number of computer system’s processors is studied.

Yu. M. Kovalev, A.Yu. Cheremokhov
VANT. Ser.: Mat. Mod. Fiz. Proc. 1997. No 3. P. 39-43.

      One-dimension air-shock wave weakening by a system of lattices or layers of dusted gas is studied within the model of frozen gas suspension. It is shown that more efficient shock wave weakening may be gained by changes in shield’s geometric configuration with conservation of material mass rate of flow.

V.P. Romanikhin
VANT. Ser.: Mat. Mod. Fiz. Proc. 1997. No 3. P. 44-47.

      Possibility of using quick Fourier transform for computing energy loss spectra of charged accelerated particles in material is considered. It is shown that the use of Fourier transform gives multiple saving of time in spectrum computations in comparison with usually used standart technique of numerical integration.

E.N. Donskoi
VANT. Ser.: Mat. Mod. Fiz. Proc. 1997. No 3. P. 48-58.

            For homogeneous and heterogeneous media with a similar chemical composition PL-estimates with finite flow dispersion at a point are developed Two approaches to the construction of PL-estimates for a homogeneous medium considered namely: the approach based on trajectory invariancy of the Markovian process related to the transport equation. The second approach allows to construct PL-analogs for well known local estimates of flow at a point, and the first one allows to develop new PL-estimates prototypes of which are artificial and not used in Monte-Carlo calculations. The principal features of the developed PL-estimates of flow at a point are the following: imbiasedness, dispersion finiteness with rather weak limitations on the source function and functional under the approach based on invariancy of the transport equation’s Green function and computation, estimation discontinuity as a detection point function at all points of the estimated functional discontinuity.
      It is shown that PL-estimates of flow at a point may be efficiently used for solving problems of radiation therapy. Essential (up to 100 time and higher in heterogeneous medium and more than 1000 times in homogeneous medium) computation time reduction, a possibility of computing a dose in the given points direct computation time dependance on a number of points, absence of statistical fluctuations on dose and isodose curves are to be stated as the advantages of using these estimates as comparable to standart estimates by the Monte-Carlo method.