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Book A Fully Coupled Monte Carlo discrete Ordinates Solution to the Neutron Transport Equation  Final Report

Download or read book A Fully Coupled Monte Carlo discrete Ordinates Solution to the Neutron Transport Equation Final Report written by and published by . This book was released on 1990 with total page 211 pages. Available in PDF, EPUB and Kindle. Book excerpt: The neutron transport equation is solved by a hybrid method that iteratively couples regions where deterministic (S{sub N}) and stochastic (Monte Carlo) methods are applied. Unlike previous hybrid methods, the Monte Carlo and S{sub N} regions are fully coupled in the sense that no assumption is made about geometrical separation or decoupling. The hybrid method provides a new means of solving problems involving both optically thick and optically thin regions that neither Monte Carlo nor S{sub N} is well suited for by themselves. The fully coupled Monte Carlo/S{sub N} technique consists of defining spatial and/or energy regions of a problem in which either a Monte Carlo calculation or an S{sub N} calculation is to be performed. The Monte Carlo region may comprise the entire spatial region for selected energy groups, or may consist of a rectangular area that is either completely or partially embedded in an arbitrary S{sub N} region. The Monte Carlo and S{sub N} regions are then connected through the common angular boundary fluxes, which are determined iteratively using the response matrix technique, and volumetric sources. The hybrid method has been implemented in the S{sub N} code TWODANT by adding special-purpose Monte Carlo subroutines to calculate the response matrices and volumetric sources, and linkage subrountines to carry out the interface flux iterations. The common angular boundary fluxes are included in the S{sub N} code as interior boundary sources, leaving the logic for the solution of the transport flux unchanged, while, with minor modifications, the diffusion synthetic accelerator remains effective in accelerating S{sub N} calculations. The special-purpose Monte Carlo routines used are essentially analog, with few variance reduction techniques employed. However, the routines have been successfully vectorized, with approximately a factor of five increase in speed over the non-vectorized version.

Book Extension of the Fully Coupled Monte Carlo

Download or read book Extension of the Fully Coupled Monte Carlo written by and published by . This book was released on 1991 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: The neutron transport equation is solved by a hybrid method that iteratively couples regions where deterministic (S{sub N}) and stochastic (Monte Carlo) methods are applied. Unlike previous hybrid methods, the Monte Carlo and S{sub N} regions are fully coupled in the sense that no assumption is made about geometrical separation of decoupling. The fully coupled Monte Carlo/S{sub N} technique consists of defining spatial and/or energy regions of a problem in which either a Monte Carlo calculation or an S{sub N} calculation is to be performed. The Monte Carlo and S{sub N} regions are then connected through the common angular boundary fluxes, which are determined iteratively using the response matrix technique, and group sources. The hybrid method provides a new method of solving problems involving both optically thick and optically thin regions that neither Monte Carlo nor S{sub N} is well suited for by itself. The fully coupled Monte Carlo/S{sub N} method has been implemented in the S{sub N} code TWODANT by adding special-purpose Monte Carlo subroutines to calculate the response matrices and group sources, and linkage subroutines to carry out the interface flux iterations. The common angular boundary fluxes are included in the S{sub N} code as interior boundary sources, leaving the logic for the solution of the transport flux unchanged, while, with minor modifications, the diffusion synthetic accelerator remains effective in accelerating the S{sub N} calculations. The Monte Carlo routines have been successfully vectorized, with approximately a factor of five increases in speed over the nonvectorized version. The hybrid method is capable of solving forward, inhomogeneous source problems in X-Y and R-Z geometries. This capability now includes mulitigroup problems involving upscatter and fission in non-highly multiplying systems. 8 refs., 8 figs., 1 tab.

Book Energy Research Abstracts

Download or read book Energy Research Abstracts written by and published by . This book was released on 1995 with total page 782 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book A Fully Coupled Monte Carlo

Download or read book A Fully Coupled Monte Carlo written by and published by . This book was released on 1990 with total page 211 pages. Available in PDF, EPUB and Kindle. Book excerpt: The neutron transport equation is solved by a hybrid method that iteratively couples regions where deterministic (S{sub N}) and stochastic (Monte Carlo) methods are applied. Unlike previous hybrid methods, the Monte Carlo and S{sub N} regions are fully coupled in the sense that no assumption is made about geometrical separation or decoupling. The hybrid method provides a new means of solving problems involving both optically thick and optically thin regions that neither Monte Carlo nor S{sub N} is well suited for by themselves. The fully coupled Monte Carlo/S{sub N} technique consists of defining spatial and/or energy regions of a problem in which either a Monte Carlo calculation or an S{sub N} calculation is to be performed. The Monte Carlo region may comprise the entire spatial region for selected energy groups, or may consist of a rectangular area that is either completely or partially embedded in an arbitrary S{sub N} region. The Monte Carlo and S{sub N} regions are then connected through the common angular boundary fluxes, which are determined iteratively using the response matrix technique, and volumetric sources. The hybrid method has been implemented in the S{sub N} code TWODANT by adding special-purpose Monte Carlo subroutines to calculate the response matrices and volumetric sources, and linkage subrountines to carry out the interface flux iterations. The common angular boundary fluxes are included in the S{sub N} code as interior boundary sources, leaving the logic for the solution of the transport flux unchanged, while, with minor modifications, the diffusion synthetic accelerator remains effective in accelerating S{sub N} calculations. The special-purpose Monte Carlo routines used are essentially analog, with few variance reduction techniques employed. However, the routines have been successfully vectorized, with approximately a factor of five increase in speed over the non-vectorized version.

Book Monte Carlo Principles and Neutron Transport Problems

Download or read book Monte Carlo Principles and Neutron Transport Problems written by Jerome Spanier and published by Courier Corporation. This book was released on 2008-01-01 with total page 258 pages. Available in PDF, EPUB and Kindle. Book excerpt: This two-part treatment introduces the general principles of the Monte Carlo method within a unified mathematical point of view, applying them to problems in neutron transport. It describes several efficiency-enhancing approaches, including the method of superposition and simulation of the adjoint equation based on reciprocity. The first half of the book presents an exposition of the fundamentals of Monte Carlo methods, examining discrete and continuous random walk processes and standard variance reduction techniques. The second half of the text focuses directly on the methods of superposition and reciprocity, illustrating their applications to specific neutron transport problems. Topics include the computation of thermal neutron fluxes and the superposition principle in resonance escape computations.

Book Nuclear Science Abstracts

Download or read book Nuclear Science Abstracts written by and published by . This book was released on 1975 with total page 764 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Scientific and Technical Aerospace Reports

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1992 with total page 564 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Nuclear Science Abstracts

Download or read book Nuclear Science Abstracts written by and published by . This book was released on 1969-10 with total page 1058 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Government Reports Announcements   Index

Download or read book Government Reports Announcements Index written by and published by . This book was released on 1994 with total page 586 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Exponential Monte Carlo Convergence of a Three Dimensional Discrete Ordinates Solution

Download or read book Exponential Monte Carlo Convergence of a Three Dimensional Discrete Ordinates Solution written by and published by . This book was released on 1999 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent work on obtaining exponential convergence for three-dimensional solutions to the spatially and angularly continuous monoenergetic transport equation with isotropic scattering using the reduced source method was promising. The method, however, used two separate estimates of the scalar flux, a Legendre expansion (in the spatial variables) and a quadrature of the angular flux. This introduced an inconsistency that may have lead to some convergence problems. To remove this inconsistency and provide a fairer test of the combined reduced source/Monte Carlo method, the method was applied to estimate the coefficients of a Legendre expansion of the solution of the discrete ordinates equations. In this case, no supplementary approximations were required.

Book ERDA Energy Research Abstracts

Download or read book ERDA Energy Research Abstracts written by United States. Energy Research and Development Administration. Technical Information Center and published by . This book was released on 1976 with total page 588 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book ERDA Energy Research Abstracts

Download or read book ERDA Energy Research Abstracts written by United States. Energy Research and Development Administration and published by . This book was released on 1976 with total page 1320 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book First Collision Source Method for Coupling Monte Carlo and Discrete Ordinates for Localized Source Problems

Download or read book First Collision Source Method for Coupling Monte Carlo and Discrete Ordinates for Localized Source Problems written by and published by . This book was released on 1985 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A difficult class of problems for the discrete-ordinates neutral particle transport method is to accurately compute the flux due to a spatially localized source. Because the transport equation is solved for discrete directions, the so-called ray effect causes the flux at space points far from the source to be inaccurate. Thus, in general, discrete ordinates would not be the method of choice to solve such problems. It is better suited for calculating problems with significant scattering. The Monte Carlo method is suited to localized source problems, particularly if the amount of collisional interactions in minimal. However, if there are many scattering collisions and the flux at all space points is desired, then the Monte Carlo method becomes expensive. To take advantage of the attributes of both approaches, we have devised a first collision source method to combine the Monte Carlo and discrete-ordinates solutions. That is, particles are tracked from the source to their first scattering collision and tallied to produce a source for the discrete-ordinates calculation. A scattered flux is then computed by discrete ordinates, and the total flux is the sum of the Monte Carlo and discrete ordinates calculated fluxes. In this paper, we present calculational results using the MCNP and TWODANT codes for selected two-dimensional problems that show the effectiveness of this method.

Book Monte Carlo Solution of a Semi discrete Transport Equation

Download or read book Monte Carlo Solution of a Semi discrete Transport Equation written by and published by . This book was released on 1999 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: The authors present the S{sub {infinity}} method, a hybrid neutron transport method in which Monte Carlo particles traverse discrete space. The goal of any deterministic/stochastic hybrid method is to couple selected characters from each of the methods in hopes of producing a better method. The S{sub {infinity}} method has the features of the lumped, linear-discontinuous (LLD) spatial discretization, yet it has no ray-effects because of the continuous angular variable. They derive the S{sub {infinity}} method for the solid-state, mono-energetic transport equation in one-dimensional slab geometry with isotropic scattering and an isotropic internal source. They demonstrate the viability of the S{sub {infinity}} method by comparing their results favorably to analytic and deterministic results.

Book INIS Atomindeks

Download or read book INIS Atomindeks written by and published by . This book was released on 1987 with total page 1414 pages. Available in PDF, EPUB and Kindle. Book excerpt: