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RUSSIAN FEDERAL NUCLEAR CENTER 
ALLRUSSIAN RESEARCH INSTITUTE OF EXPERIMENTAL PHYSICS 

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Issue N^{o} 3, 2008  COMPUTATION DIFFERENCE METHOD OF ELECTROMAGNETIC FIELD DISTRIBUTION IN PARABOLIC RADIATOR CAVITY
A. L Golubev, L V. Dolzhenkov, A. V. Soldatov VANT. Ser.: Mat. Mod. Fiz. Proc. 2008. No 3. P. 318.
Described here is the computation method for parabolic cavity electrodynamics based on the numerical solution of 3D homogeneous Maxwell equations represented in parabolic coordinates. The electromagnetic field sources are specified in the form of the boundary conditions on the parabolic inner space. The natural boundary conditions used in the parabolic symmetry axis are as follows: electric and magnetic field components should be limited in this axis; besides, vector components of electric and magnetic fields along the symmetry axis should not be dependent of the azimuth angle. The approximate formulas for space derivatives are derived in terms of integral effects of Maxwell equations for difference grid unit cell. Coordinatewise splitting method is used in time approximation of derivatives. The applicability and accuracy of solution are shown using the computation of representative test problem with analytical solution.
 DIAGONAL ELEMENT ISOLATION METHOD FOR ITERATION ACCELERATION FOR NEUTRON TRANSPORT EQUATION A. D. Gadzhiev, I. A. Kondakov, A. A. Shestakov VANT. Ser.: Mat. Mod. Fiz. Proc. 2008. No 3. P. 1931.
The paper considers one of the implementations of diagonal element isolation method for integral collision iteration acceleration for ID neutron transport equation.
 COMPUTATION METHOD FOR PARALLEL SOLUTION OF HEAT CONDUCTIVITY EQUATION ON NONSTRUCTURED GRIDS IN MEDUZA TECHNIQUE A. A. Gorbunov VANT. Ser.: Mat. Mod. Fiz. Proc. 2008. No 3. P. 3246.
Described here are computation method and program used in MEDUZA technique for 2D equation of radiative heat conductivity on nonstructured polygonal grid. The implicit difference scheme is used for heat conductivity equation approximation. Heat conductivity coefficient is calculated using the previous iteration temperature of equation of state nonlinearity. The boundaries are simulated with mixed cells which are calculated with interface separation mechanism. The parallel library version of linear PMLP solvers is used in heat conductivity program which allows parallel calculations. The applicability of the program is demonstrated by the example of calculation of three test problems. Given here are the estimations of parallelization efficiency for one of the test problems.
 ON THE QUESTION OF SLOW NEUTRON SCATTERING DESCRIPTION IN ENDF D. G. Modestov VANT. Ser.: Mat. Mod. Fiz. Proc. 2008. No 3. P. 4754.
The suggested IAEA ENDF data libraries are, perhaps, the most widely used in neutron moderation transport problems. Still there is a number of errors in the format description, which could result in unphysical dependence of the scattering crosssection on the energy. The paper considers the analysis of one of these errors concerning the representation of scattering law in approximation of instantaneous collision.
 INSTANTANEOUS COLLISION APPROXIMATION FOR SIMULATION OF SLOW NEUTRON TRANSPORT D. G. Modestov VANT. Ser.: Mat. Mod. Fiz. Proc. 2008. No 3. P. 5567.
The estimated ENDF nuclear data libraries are often used in problems in which the lowenergy neutron transport plays an important role. In this case, the incoherent inelastic scattering reaction is, perhaps, the most complicated for realization among the reactions typical of thermal neutrons. Here, the representation of scattering law in the instantaneous collision approximation is the most frequently used yet the least investigated representation. Given here is the explicit form of the integrated crosssection in this approximation, and sampling algorithm of scattering parameters required for transport problem solution using statistical simulation techniques. The comparison with BRAND technique is given.
 STIELTJES CALCULATION OF MULTIGROUP ROSSELAND AND PLANCK PHOTON LENGTHS G. M. Eliseev, V. G. Eliseev, N. N. Zhilnikova, P. G. Kuznetsov, A. V. Tikhonov VANT. Ser.: Mat. Mod. Fiz. Proc. 2008. No 3. P. 6873.
Described here is the calculation method of product quadrature of two functions using Stieltjes integration. Stieltjes integration function is represented as Riemann integral of one of the functions with variable upper limit. It is approximated by the fourthorder polynomial Hermitian interpolating spline local on the average. The application of the method to calculate multigroup photon lengths in materials with weighting Rosseland and Planck function reduces the calculation time by approximately 30%. Given here are Fortran codes to calculate the integrals of these weighting functions.
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