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Since 1978
Published in Sarov (Arzamas-16), Nizhegorodskaya oblast |
RUSSIAN FEDERAL
NUCLEAR CENTER -
ALL-RUSSIAN RESEARCH INSTITUTE
OF EXPERIMENTAL PHYSICS |
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 Русский |  English
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Issue No 4, 2015 |
TDMCC CODE APPLICATION TO SOLVE PROBLEMS WITH A DOMINANT RATIO CLOSE TO ONE
E. F. Mitenkova, T. V. Semenova
VANT. Ser.: Mat. Mod. Fiz. Proc. 2015. No 4. P. 3-14.
New capabilities of the TDMCC code for the analysis of the fission rate distribution in weakly coupled systems are presented. The methods implemented in the TDMCC code to calculate the dominant ratio and Shennons entropy are considered. For systems with the dominant ratio value close to 1, the relation between the convergence rate of functionals and Shennons entropy is demonstrated. An example is given, in which underestimation of errors in the calculated functionals and the specifics of the algorithms used to solve the criticality problems lead to inconsistent results in various options of computations with small variations of the original system parameters.
Key words: Monte Carlo method, method of generations, a weakly coupled system, dominant ratio, Shennon entropy.
| | SIMULATION OF THE FUEL ELEMENT CLADDING MELTING AND THE MELT TRANPORT IN A FUEL ASSEMBLY OF THE BN-TYPE REACTOR USING THE SOKRAT-BN CODE I. S. Vozhakov, E. V. Usov, V. S. Zhdanov, M. E. Kuznetsova, A. E. Kiselev, R. V. Chalyi
VANT. Ser.: Mat. Mod. Fiz. Proc. 2015. No 4. P. 15-21.
The paper subject is the development of the model of melting and transport of a fuel element cladding and its implementation in the SOKRAT-BM code used for the analysis and safety justification of NPPs with the BN-type reactors. The code allows numerically simulating the dynamics of fast neutron reactors with sodium coolants under abnormal operation conditions, in cases of the design basis and beyond the design basis accidents. The numerical simulation of the normal operation and emergency operation conditions is one of the major approaches to the safety justification of reactor operation. The specifics of fast neutron reactors is in high values of the specific energy release and low working pressures and, as a result, with the coolant boiling under the emergency conditions with flow loss the vapor flow rate may reach several hundred meters per second thereby significantly affecting the flow dynamics of the molten materials of fuel elements. The motion of the molten fuel elements and structural elements is followed by the reactivity changes in reactor and may cause the generation of both the lower and upper locks in some fuel assemblies and, hence, to the redistribution of the coolant flows in the first loop of the reactor core.
For the simulation of the molten cladding motion it is suggested to take into account the main specific features of the cladding flow process in fast reactor. In particular, it is assumed that the molten material moves along the given fuel element as a film of a varying thickness depending on the amount of melt and the molten material dynamics is governed by the force of gravity, friction between the melt and gas flow, and friction between the melt and solid wall. The specific feature of the model is in strict identification of the molten material boundaries and this allows circumventing numerical diffusion, i.e. the melt is not spread over the entire computational domain, but have clearly defined boundaries moving in accordance with the physics of these processes.
To demonstrate the described model applicability, results of simulations are presented both for the problems having analytical solutions and those modeling the real reactor plants. It is shown that the numerical simulation with the model of melting and transport of a fuel element cladding adequately describes the processes in a number of problems, such as the problem of a melting cylinder and the problem of a melt flowing under gravitational forces and friction between the molten material and coolant flow.
Key words: fast reactor, fuel element, cladding, melting, simulation, SOKRAT-BN.
| | SIMULATION OF THE RADIATION-INDUCED ACCUMULATION OF POINT DEFECTS IN TITANIUM HYDRIDE USING THE KINETIC MONTE CARLO METHOD V. A. Khlebnikov, A. V. Yanilkin
VANT. Ser.: Mat. Mod. Fiz. Proc. 2015. No 4. P. 22-33.
The paper presents simulation results for the generation and evolution of defects in titanium targets of pulse neutron sources during their operation. Two approaches are compared: the explicit description of atomic diffusion on a rigid lattice and solution of a system of kinetic equations of the cluster dynamics. The kinetic Monte Carlo method is used in the both approaches. The time dependencies have been obtained for the concentrations of point defects and their aggregates, the size distribution of aggregates has been constructed.
Key words: radiation damage, the kinetic Monte Carlo method, cluster dynamics, SPPARKS program package.
| | APPLICATION OF THE ALGORITHM IDENTIFYING AN EQUILIBRIUM PART OF SPECTRUM DURING THE SIMULATION OF THE RADIATION TRANSPORT PROBLEMS WITH SPECTRAL DIFFUSION N. G. Karlykhanov, I. V. Chindyaev
VANT. Ser.: Mat. Mod. Fiz. Proc. 2015. No 4. P. 34-47.
The issues of constructing an algorithm identifying an equilibrium part of spectrum, which has been used to solve the radiation transport problems with spectral diffusion, are discussed. The algorithm implementation includes the automatic selection of equilibrium groups, as well as the account of the resulting internal boundary conditions. The method applicability is illustrated by the example of solving a number of problems.
Key words: radiation transport, spectral diffusion, identification of an equilibrium part of spectrum.
| | FRIS LANGUAGE SERVICE FOR THE EFFECTIVE DEVELOPMENT OF FORTRAN APPLICATIONS: A REVIEW OF CAPABILITIES I. S. Ratkevich
VANT. Ser.: Mat. Mod. Fiz. Proc. 2015. No 4. P. 48-57.
The FRIS language service capabilities providing an extended support for the effective development of Fortran applications in Microsoft Visual Studio are discussed. The FRIS capabilities are compared with those of the most commonly used analogs by Intel and PGI.
Key words: FRIS, Fortran Intelligent Solutions, Visual Studio extension, language service, Fortran-2003.
| | ANALYSIS AND ASSESSMENT OF VISUALIZATION SYSTEMS USED IN SOFTWARE FOR PARALLEL COMPUTATIONS V. L. Averbukh, O. G. Annenkova, M. O. Bakhterev, D. V. Manakov
VANT. Ser.: Mat. Mod. Fiz. Proc. 2015. No 4. P. 58-70.
Approaches to visualizing routs and graphs of parallel program calls using a number of software visualization metaphors are considered. The applicability of metaphors on the basis of visualization criteria has been analyzed. Examples of using tools for visualizing the process of developing system software of a lower level for modern parallel-architecture processors are given.
The authors state the problem of formally describing and/or verifying the visualization results.
Key words: software visualization, execution route, call graph, visualization metaphor.
| | A PROTECTED FIBER-OPTIC SYSTEM FOR TRANSMISSION OF CONFIDENTIAL DATA FOR MULTILOOP DISTRIBUTED COMPUTER-AIDED SYSTEMS WITH DISCRIMINATION OF THE USER ACCESS RIGHTS V. V. Shubin
VANT. Ser.: Mat. Mod. Fiz. Proc. 2015. No 4. P. 71-80.
The paper describes a protected fiber-optic system for confidential data transmission on the basis of data protection controllers FOBOS with the use of WDM for communication and supervisory channels. It is demonstrated that the coarse wave division multiplexing (CWDM) technology allows creating a multiloop (up to 10 loops) distributed computer-aided system of an enterprise with protection against leakage of information during the transmission of data via an optical channel outside the supervised zone. The transmission at a distance of 20-30 km with the transmission rate 10,31 Gbit/s and at a distance of 37,5 km with the transmission rate 1,25 Gbit/s is provided. The control system’s sensitivity with the wavelength 1610 nm improves from 0,03 dB to 0,004-0,013 dB within the range of wavelengths 1270-1450 nm. The protected fiber-optic transmission system provides the point-to-point communication and allows constructing distributed multiloop computer-aided systems of any topology using a minimum number of optic fibers.
Key words: protected fiber-optic system for confidential data transmission, data protection controller, different access rights.
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