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Eigenvalue methods for time-dependent neuton diffusion

Submitted by Marcele Costal de Castro (costalcastro@gmail.com) on 2017-12-14T13:31:22Z
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Previous issue date: 1969-05 / The analysis of pulsed neutron experiments in multiplying and in nonmultiplying domains is considered. The analysis is based on the one-dimensional diffusion theory modelo In one-group models, a scalar version of problems similar to those of Sturm Liouville systems is generated; while in multigroup models, a vector version is required. An algorithm is suggested which allows the complete solution of the general scalar problem in all separable geometries of interest, for homogeneous boundary conditions. The results are the time igenvalues and the spatial eigen functions. The algorithm is suitable for direct computer implementation. Examples of application are given. The multigroup problem can be solved by adequate extensions of the one-group algorithm. Since the associated operators are nonselfadjoint, the eigenvalues form in general a spectrum that has a discrete plus a continuous part. All of the discrete spectrum can be obtained using the suggested method. An example with two groups of neutrons in a three-region domain is given. Extensions to inhomogeneous equations and boundary conditions are considered. Application of the methods to other problems rather than the pulsed neutron problem are studied. The method is shown to be useful in the solution of nonlinear boundary-value problems. Pulsed neutron experiments can be analyzed as problems similar to Sturm-Liouville systems. The scalar problems are completely solved here. The vector problems are partially solved. Some progress in the mathematical theory of nonselfadjoint operators is required for the complete solution of the vector problem.

Identiferoai:union.ndltd.org:IBICT/oai:carpedien.ien.gov.br:ien/2029
Date05 1900
CreatorsOliveira, Roberto Gomes de, Instituto de Engenharia Nuclear
ContributorsNão, localizado
PublisherInstituto de Engenharia Nuclear, Eletrical Engineering, IEN, Estados unidos, Stanford University
Source SetsIBICT Brazilian ETDs
LanguageEnglish
Detected LanguageEnglish
Typeinfo:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/doctoralThesis
Sourcereponame:Repositório Institucional do IEN, instname:Instituto de Engenharia Nuclear, instacron:IEN
Rightsinfo:eu-repo/semantics/openAccess

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