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Final report [on solving the multigroup diffusion equations]

Description: Progress achieved in the development of variational methods for solving the multigroup neutron diffusion equations is described. An appraisal is made of the extent to which improved variational methods could advantageously replace difference methods currently used. (DG)
Date: January 1, 1975
Creator: Birkhoff, G.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Integral transport treatment of transitional resonance spectra

Description: Analytical exploratory investigations indicated that transition effects such as streaming will cause a considerable spatial variation in the neutron spectra across resonances; streaming leads to opposite effects in the forward and backward directions. The neglect of this spatial and angular variation of the transitory resonance spectra is an approximation that is common to all current methodologies. An integral transport theory formalism was developed for the description of spatially dependent … more
Date: January 1, 1988
Creator: Hill, R. N.; Ott, K. O. & Rhodes, J. D.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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A variable timestep generalized Runge-Kutta method for the numerical integration of the space-time diffusion equations

Description: A generalized Runge-Kutta method has been employed in the numerical integration of the stiff space-time diffusion equations. The method is fourth-order accurate, using an embedded third-order solution to arrive at an estimate of the truncation error for automatic timestep control. The efficiency of the Runge-Kutta method is enhanced by a block-factorization technique that exploits the sparse structure of the matrix system resulting from the space and energy discretized form of the time-dependen… more
Date: September 1, 1991
Creator: Aviles, B.N.; Sutton, T.M. & Kelly, D.J. III.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Asymptotic derivation of the simplified P[sub n] equations

Description: The diffusion and simplified P[sub N] equations are derived from the transport equation by means of an asymptotic expansion in which the diffusion equation is the leading order approximation and the simplified P[sub N] equations are higher-order approximations. In addition, the simplified P[sub N] equations are reformulated in a canonical'' form that greatly facilitates the formulation of boundary conditions and the implementation of the resulting problem in a conventional multigroup diffusion … more
Date: January 1, 1993
Creator: Larsen, Edward W.; Morel, Jim E. & McGhee, John M.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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A three-dimensional nodal neutron kinetics capability for relaps

Description: The incorporation of a three-dimensional neutron kinetics capability into the DOE version of the RELAP5/MOD3.2 reactor safety code is discussed. A brief discussion of the kinetics method is given along with a discussion of the cross section parameterization models available in RELAP5/MOD3.2. The RELAP5/MOD3.2 code is then used to perform calculations of the NEACRP rod ejection and rod withdrawal benchmarks, and results are presented.
Date: May 1, 1996
Creator: Judd, J. L. & Weaver, W. L.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Two-dimensional finite element neutron diffusion analysis using hierarchic shape functions

Description: Recent advances have been made in the use of p-type finite element method (FEM) for structural and fluid dynamics problems that hold promise for reactor physics problems. These advances include using hierarchic shape functions, element-by-element iterative solvers and more powerful mapping techniques. Use of the hierarchic shape functions allows greater flexibility and efficiency in implementing energy-dependent flux expansions and incorporating localized refinement of the solution space. The i… more
Date: April 1, 1997
Creator: Carpenter, D.C.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Theory and application of the RAZOR two-dimensional continuous energy lattice physics code

Description: The theory and application of the RAZOR two-dimensional, continuous energy lattice physics code are discussed. RAZOR solves the continuous energy neutron transport equation in one- and two-dimensional geometries, and calculates equivalent few-group diffusion theory constants that rigorously account for spatial and spectral self-shielding effects. A dual energy resolution slowing down algorithm is used to reduce computer memory and disk storage requirements for the slowing down calculation. Resu… more
Date: April 1, 1997
Creator: Zerkle, M.L.; Abu-Shumays, I.K.; Ott, M.W. & Winwood, J.P.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Development of a parallelization strategy for the VARIANT code

Description: The VARIANT code solves the multigroup steady-state neutron diffusion and transport equation in three-dimensional Cartesian and hexagonal geometries using the variational nodal method. VARIANT consists of four major parts that must be executed sequentially: input handling, calculation of response matrices, solution algorithm (i.e. inner-outer iteration), and output of results. The objective of the parallelization effort was to reduce the overall computing time by distributing the work of the tw… more
Date: 1996-11~
Creator: Hanebutte, U. R.; Khalil, H. S.; Palmiotti, G. & Tatsumi, M.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

A bibliography on finite element and related methods analysis in reactor physics computations (1971--1997)

Description: This bibliography provides a list of references on finite element and related methods analysis in reactor physics computations. These references have been published in scientific journals, conference proceedings, technical reports, thesis/dissertations and as chapters in reference books from 1971 to the present. Both English and non-English references are included. All references contained in the bibliography are sorted alphabetically by the first author`s name and a subsort by date of publicat… more
Date: January 1, 1998
Creator: Carpenter, D.C.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Static benchmarking of the NESTLE advanced nodal code

Description: Results from the NESTLE advanced nodal code are presented for multidimensional numerical benchmarks representing four different types of reactors, and predictions from NESTLE are compared with measured data from pressurized water reactors (PWRs). The numerical benchmarks include cases representative of PWRs, boiling water reactors (BWRs), CANDU heavy water reactors (HWRs), and high-temperature gas-cooled reactors (HTGRs). The measured PWR data include critical soluble boron concentrations and i… more
Date: May 1, 1997
Creator: Mosteller, R.D.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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A two-dimensional, semi-analytic expansion method for nodal calculations

Description: Most modern nodal methods used today are based upon the transverse integration procedure in which the multi-dimensional flux shape is integrated over the transverse directions in order to produce a set of coupled one-dimensional flux shapes. The one-dimensional flux shapes are then solved either analytically or by representing the flux shape by a finite polynomial expansion. While these methods have been verified for most light-water reactor applications, they have been found to have difficulty… more
Date: August 1, 1995
Creator: Palmtag, S.P.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries Government Documents Department
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The use of active learning strategies in the instruction of Reactor Physics concepts

Description: Each of the Active Learning strategies employed to teach Reactor Physics material has been or promises to be instructionally successful. The Cooperative Group strategy has demonstrated a statistically significant increase in student performance on the unit exam in teaching conceptually difficult, transport and diffusion theory material. However, this result was achieved at the expense of a modest increase in class time. The Tutorial CBI programs have enabled learning equally as well as classroo… more
Date: January 1, 2000
Creator: Robinson, Michael A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Theory and application of deterministic multidimensional pointwise energy lattice physics method

Description: The theory and application of deterministic, multidimensional, pointwise energy lattice physics methods are discussed. These methods may be used to solve the neutron transport equation in multidimensional geometries using near-continuous energy detail to calculate equivalent few-group diffusion theory constants that rigorously account for spatial and spectral self-shielding effects. A dual energy resolution slowing down algorithm is described which reduces the computer memory and disk storage r… more
Date: October 5, 1999
Creator: Zerkle, M.L.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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The use of particle tracks in problem analysis

Description: The visualization of the microscopic phenomena in a Monte Carlo simulation can improve the understanding of the problem and provide an important check on the model definition and execution. The paths, or tracks, of a sample of the Monte Carlo particles show how fission source neutrons migrate from one generation to another. The location of fission source neutrons and interactions can be shown by event markers. This new visualization is available for the Monte Carlo n-particle code MCNP due to t… more
Date: June 1, 1995
Creator: Van Riper, K.A.; McKinney, G.W. & Urbatsch, T.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Iterative acceleration methods for Monte Carlo and deterministic criticality calculations

Description: If you have ever given up on a nuclear criticality calculation and terminated it because it took so long to converge, you might find this thesis of interest. The author develops three methods for improving the fission source convergence in nuclear criticality calculations for physical systems with high dominance ratios for which convergence is slow. The Fission Matrix Acceleration Method and the Fission Diffusion Synthetic Acceleration (FDSA) Method are acceleration methods that speed fission s… more
Date: November 1, 1995
Creator: Urbatsch, T.J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Differencing the diffusion equation on unstructured meshes in 2-D

Description: During the last few years, there has been an increased effort to devise robust transport differencings for unstructured meshes, specifically arbitrarily connected grids of polygons. Adams has investigated unstructured mesh discretization techniques for the even- and odd-parity forms of the transport equation, and for the more traditional first-order form. Conversely, development of unstructured mesh diffusion methods has been lacking. While Morel, Kershaw, Shestakov and others have done a great… more
Date: October 24, 1994
Creator: Palmer, Todd S.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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