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RUSSIAN FEDERAL NUCLEAR CENTER 
ALLRUSSIAN RESEARCH INSTITUTE OF EXPERIMENTAL PHYSICS 

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Issue N^{o} 3, 1996  ON EXPERIENCE OF PARALLELING GAS DYNAMIC PROBLEM COMPUTATION USING DMK PROGRAMS ON MULTIPROCESSOR SYSTEMS
V.N. Motlokhov, V.V. Rasskazova, I.D. Sofronov VANT. Ser.: Mat. Mod. Fiz. Proc. 1996. No 3. P. 38.
Methods and techniques of computation paralleling are demonstrated which authors experienced when parallel computation arrangement was of narrow directed character persued specific objectives. Algorithm of paralleling DMK (2D gas dynamic problem computation on nonregular polygonal and regular quadrangular grids) program is proposed.
 LOGISTICS OF SMOOTH GRID GENERATION IN COMPOSITE DOMAINS G.P. Prokopov, O.I. Sofronova VANT. Ser.: Mat. Mod. Fiz. Proc. 1996. No 3. P. 917.
Problems of description of grid and domain structure allowing to automatize to great extent the process of cutting composite domain into rectangular structure blocks in plane of grid node numbers. It is possible to solve grid generating equations obtained using variational functionals or direct approximation of differentional equations by means of local algorithms which can be easily parallelized for multiprocessor computer systems. The logistics described allows to provide grid smoothness for the entire composite domain.
 ON POTENTIONAL REDUCTION AND IDENTIFICATION OF SEISMIC SIGNAL OF UNDERGROUND NUCLEAR EXPLOSION V.A. Bychenkov, N.S. Zhilyayeva, G.V. Kovalenko, I.I. Kuznetsova, V.F. Kuropatenko, A.V. Skovpen, L.V. Khardina VANT. Ser.: Mat. Mod. Fiz. Proc. 1996. No 3. P. 1826.
The paper presents the results of computational and theoretical research on seismic effects of contained underground nuclear explosion in: air cavities; alluviumtype porous soil; cavity filled with porous matter, graphite in particular. The following basic results have been obtained. Radius of air cavity providing maximum attenuation of seismic signal is ~ 32 m/kt^{1/3}. The paper presents a model of weakened rock nearby cavity. The conditions of explosion in alluvium exist when seismic signal practically vanishes at low frequencies. At explosion in alluvium seismic sources of nuclear and chemical explosion may distinguish essentially. The 0,01 g/cm^{3}density graphite in the 15 m/kt^{1/3}radius cavity reduces seismic efficiency of explosion in granite by more than 50 times.
 SOLUTION CONSTRUCTION IN THE PROBLEM OF STRATIFIED SHELL MOTION G.V. Dolgoleva, A.V. Zabrodin VANT. Ser.: Mat. Mod. Fiz. Proc. 1996. No 3. P. 2734.
Method of solution construction in the problems of mathematical modeling of stratified shell system motion is presented. Such systems are studied in various works within various projects on controlled thermonuclear fusionimplementation. They constitute structures of thin (relative to their linear sizes) planar, cylindrical or spherical nested layers. Layer destination and selection consists in arrangement of a part of contributed energy cumulation in system geometrical center. Cumulation efficiency is estimated by the fraction of energy that is extracted by this converging part. The final objective of the investigations is to determine cumulating energy amount and determination of its dependence on the particular microtarget design and energy contribution techniques. Knowledge of these mechanisms allows to investigate various microtarget schemes and preliminarily select from them those with most suitable output cumulation parameters. This essentially narrows the variety of schemes for subsequent detailed consideration and final conclusion.
 ECRAN PROGRAM FOR COMPUTATION OF EFFECTIVE FACTOR OF NEUTRON MULTIPLICATION IN REACTOR FACILITIES A.N. Moskvin, A.V. Nikiforova, A.P. Trubitsyn, G.G. Farafontov, R.M. Shagaliev, V.A. Shumilin VANT. Ser.: Mat. Mod. Fiz. Proc. 1996. No 3. P. 3539.
This program is designed for computations of the effective neutron multiplication factor and neutron spectrum in multigroup twodimensional kinetic approximation in cylindrical and plane geometries. The following iterative techniques of computation of effective neutron multiplication factor are implemented in the program: Kellog technique, direct iterative technique, method of fission source iteration and combined technique. This paper compares efficiency of these methods on test problems for various types of reactors (WWER, RBMK, SNR). To speed up simple iteration convergency within one group the consistent FCAmethod is used. To speed up external iteration convergency in the fission source iteration method, the Chebyshev technique and successive upper relaxation techique are used.
 DATABASE FOR NUMERICAL SIMULATION OF FRAGMENT ACCUMULATION IN POWER REACTOR FUEL S.N. Abramovich, V.P. Gorelov, A.A. Gorshikhin, A.N. Grebennikov, G.G. Farafontov, V.I. Il’yin VANT. Ser.: Mat. Mod. Fiz. Proc. 1996. No 3. P. 4061.
The database needed for numerical simulation of processes of binary fission fragment accumulation in power nuclear reactor fuel is discussed. The total amount of a great quantity of fragments is suggested to replace with the simplified model. Recommendations on using estimated characteristics of neutron interaction with separated fragments are given. For a great number of fission nuclear tables are presented showing yields of separated fragments, isotopes, total yields of light and heavy stable slug fragments and yields of effective light and heavy stable slug fragments. CONVERT and SUMMER programs are presented which are needed for extraction of the required values from estimated data and calculation of characteristics of neutron interaction with efficient light and heavy stable slug fragments. Algorithm implemented in SUMMER program for computation of characteristics of neutron interaction with effective fragments is given.
 RECOMMENDATIONS ON NEUTRONNUCLEAR DATA SELECTION FOR NUMERICAL SIMULATION OF ACTINIDE ACCUMULATION PROCESSES IN POWER REACTOR FUEL S.N. Abramovich, V.P. Gorelov. A.N. Grebennikov, B.Ya. Guzhovskii, G.G. Farafontov, V.I. Il’yin VANT. Ser.: Mat. Mod. Fiz. Proc. 1996. No 3. P. 6270.
Recommendations on neutronnuclear data selection for numerical simulation of actinide nuclei accumulation in energy reactor fuel are given. ENDL82, JENDL3, ENDF/B6 and BROND2 libraries of estimated data on neutron interaction with nuclei of ^{232,233}Th, ^{231233}Pa, ^{232239}U, ^{237239}Np, ^{236,238,239}Pu, ^{241244}Am, ^{242m,244m}Am and ^{242249}Cm are considered. RESINT program for processing data arrays corresponding to above listed libraries which was used to conduct attendant computations is presented.
 COMPUTATION OF SOLID PARTICLE TRANSPORT BY MOVING MEDIA USING DMК PROGRAM V.V. Rasskazova, A.N. Shaporenko VANT. Ser.: Mat. Mod. Fiz. Proc. 1996. No 3. P. 7176.
Problems of program and technique development to provide computations of transport of individual nonderforrned particles in moving media using nonregular Lagrangian grid in 2D approximation are considered.
 PARALLEL ALGORITHMS FOR SOLVING 3D HEAT CONDUCTION EQUATION AND RESULTS OF DEMONSTRATION PROBLEM COMPUTATIONS ON EIGHTPROCESSOR COMPUTER SYSTEM MP3 WITH DISTRIBUTED MEMORY O.I. Butnev, A.N. Bykov, B.L. Voronin, S.I. Skrypnic, I.D. Sofronov VANT. Ser.: Mat. Mod. Fiz. Proc. 1996. No 3. P. 7784.
The paper presents the description of parallel algorithms for solving 3D heat conduction equation and computation results of test problem on cube cooling obtained using eightprocessor computer system MP3 with distributed memory. Differentia] and finitedifference equations, scheme of spliting by directions, finitedifference equation solving technique are given. Two approaches to massively parallel computation arrangement are implemented and studied. Parallelization efficiency dependence on technique of problem geometrical decomposition for two modes of MP3 processor loading is investigated. Computations were carried out using orthogonal and nonorthogonal grids.
 COMPUTATION OF ELASTIC SCATTERING CHARACTERISTICS OF ACCELERATED IONS IN MATERIAL V.P. Romanikhin VANT. Ser.: Mat. Mod. Fiz. Proc. 1996. No 3. P. 8589.
Computer implementation of exact and sufficiently fast technique of elastic scattering angle computation for accelerated ions in material atoms with arbitrary potentials of interatomic interaction is presented. This technique is based on 2D spline interpolation of classical scattering integral for which computation adaptive procedure of numerical integration was used based on sevenpoint, quadrature Gauss formula. The technique may be used in problems of stochastic modeling fast charged partical interaction with the material.
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