COMPUTER KERNEL OF THE ACCOUNTING AND CONTROL SYSTEM FOR NUCLEAR MATERIALS

V.I. Vlasov, S.S. Zhikharev, R.I. Ilkaev, N.M. Mikiichuk, E.E. Santalova, I.D. Sofronov, O.N. Tazetdinov, V.N. Tsvetkov, V.A. Tsukanov, V.I. Yuferev
VANT. Ser.: Mat. Mod. Fiz. Proc. 1996. No 1-2. P. 3-10.

      The description is given for the central subsystem (computer kernel) of the demonstration model for nuclear material control and accounting system (MC&A).
      
      The local area network structure is described, the basic requirements and functions of the computerized MC&A system are presented for the choice of basic software, the content and functions of the applications are shown, a brief description is given for the structure of the basic database.
      The software developed for the demonstration model allows to implement I he majority of functions and requirements needed for accounting and control of nuclear materials and serves good base for the creation of the MC&A system tailored for the actual use.

F.I. Kornilova, E.P. Troitsky, E.L. Shnepov
VANT. Ser.: Mat. Mod. Fiz. Proc. 1996. No 1-2. P. 11-18.

            The description is presented for the hardware and software of the testing system for the operating system of the data communications system station. The goal of the work was to provide a systematic computerized check of the operating system prior to the adoption for the experimental operation under frequent changes both in the hardware and software of the network. The set, of benchmarks ensures the sufficient checking completenc.es which contributes to the higher reliability and stability of the entire network.

V.A. Pervov, E.P. Troitsky. L.V. Kholostova, E.L. Shnepov
VANT. Ser.: Mat. Mod. Fiz. Proc. 1996. No 1-2. P. 19-23.

      Personal computers used as terminals within the communications systems are able to operate in the file transfer mode. The user is provided with the tools to convert the virtual communications link connected created upon his request and to any host computer to the fde operation within the heterogeneous computing complex. To increase the communications rate the pipeline principle was used which allowed the growth of the virtual link throughput by 1,7-2 times and make the communications rate independent of the communications link length. The measurements were made to evaluate the efficiency of the proposed solutions.

V.Yu. Gusev, M.Yu. Kozmanov
VANT. Ser.: Mat. Mod. Fiz. Proc. 1996. No 1-2. P. 24-33.

      This paper is devoted to constructing monotonous difference schemes for the transport equation. The presented methods can be used for solving radiative transfer or propagation of atmospheric pollutant problems.
      The results of calculation of model problems are presented in comparison with exact solutions.

V.M. Maslov
VANT. Ser.: Mat. Mod. Fiz. Proc. 1996. No 1-2. P. 34-46.

      The determining relations in the form of the finite increments represent the evolution of the dissipative system as a sequence of self-organization acts where the state parameter is the functional of the geometrical discrete transformation.
      The strengthening and accumulation of damages as a component of the deformation process is described by the unique parametric space. They are controlled by two factors: energy levels of the elastic field and self-organization acts and the boundary of the deterministic chaos of the state parameter.
      For the axial loading, the description is given for the small cycle loading, unloading, strength yield and long-term strength. The determining relation for three-axis stress state is proposed for the perfect medium; using the coplanarity hypothesis, a model version was considered for the plane deformation curve.

V.P. Romanikhin
VANT. Ser.: Mat. Mod. Fiz. Proc. 1996. No 1-2. P. 47-52.

      The approximate analytical solutions are found for the response function of α-spectrometer with a semiconductor detector. The conclusion was made in the assumption that the main cause of the asymmetry of peaks of α-spectra for the measurements with aperture angles is the angular scattering of α-particles trajectories. The derivation of the response function used the simplified equation for energy losses of α-particles. The computational methods are developed to calculate the response function on a computer and the numerical model is implemented for the recording of α-spectra having the minimum possible number of unknown parameters to be adjusted. The test computations of a single line of the hardware spectrum from ²⁴²Pu α-emission demonstrated a good qualitative agreement of computational and actual spectra.

L.F. Gudarenko, V.M. Povyshev
VANT. Ser.: Mat. Mod. Fiz. Proc. 1996. No 1-2. P. 53-58.

      The goal was to develop efficient algorithms for the calculation of free parameters for two types of analytical dependences used in the equations of state to describe potential pressure; to perform the computations for the evaluation of the approximation properties of these dependences, to compare them with the other analytical dependence.
      The description is given for the algorithms developed. The calculation of free parameters reduces to simultaneous minimization and calculation of the systems; no initial approximations are needed for the parameters to be computed. The initial data are represented by the table of potential pressure values depending in the relative compression. For three forms of analytical dependences, the computations were performed to approximate the potential pressure in copper and lead in the density range ρ₀ < ρ < 90ρ₀. One of the dependences is recommended for the use in the wide range equations of state.

A.T. Sapozhnikov
VANT. Ser.: Mat. Mod. Fiz. Proc. 1996. No 1-2. P. 59-61.

      Under natural restrictions to thermal equations of state for the components (Bethe-Weil restrictions), the proof is obtained for the existence and uniqueness of the solution for the system of equations for thermodynamic equilibrium of multicomponent heterogeneous mixture. It is shown that the solution can be nonunique for nonisothermal isotherms.

A.A. Shestakov
VANT. Ser.: Mat. Mod. Fiz. Proc. 1996. No 1-2. P. 61-74.

      The paper considers numerical solutions of energy and radiation transport equations in multigroup P₁-approximation including Compton scattering.
      The calculations of photon transport in high temperature plasma requires accounting for Compton scattering on moving electrons. When low frequency photons are scattering on fast electrons the photon energy increases.
      To account for Compton scattering, Focker-Plank equations must be solved. The paper studies the properties of numerical solutions for Focker-Plank equation obtained with various difference schemes. It is shown that the difference scheme with weight parameters has the second order approximation over the energy variable, gives the monotonic positive solution and retains the number of particles in the system.

O.I. Morozov
VANT. Ser.: Mat. Mod. Fiz. Proc. 1996. No 1-2. P. 75-83.

      The study is performed for the integrability of self-smular Lagrangian equations for 1-D dynamics of polytropic gas. These equations are reduced to Abelian equations for which the studies are performed for reducibility to linear equations, split-variable equations as well as the cases of existence for linear solutions. This allows to find new analytical solutions for gas-dynamic equations.

R.N. Antonova, G.P. Prokopov, O.I. Sofronova
VANT. Ser.: Mat. Mod. Fiz. Proc. 1996. No 1-2. P. 84-90.

      The adaptive grid generating algorithm for solving unstable problems of mathematical physics is suggested. Each step of this algorithm begins from the calculation of the shift of the interior nodes of the grid by means of interpolation formulas using the values of the shift of boundary nodes. The addition of the shifts to the coordinates of nodes of the grid on the previous timestep gives the initial grid for the next timestep. From the latter grid the iteration process minimizing some variational functional starts. As an illustration two examples of conversion from the simple domain to the domain having form for which interpolation formulas give unacceptable grid are considered.