Accession Number : AD0663369

Title :   ENERGY-DEPENDENT NEUTRON TRANSPORT THEORY NEAR A TEMPERATURE DISCONTINUITY,

Corporate Author : RAND CORP SANTA MONICA CALIF

Personal Author(s) : Gritton,Eugene C. ; Leonard,Anthony

Report Date : DEC 1967

Pagination or Media Count : 79

Abstract : An exact solution is obtained for the energy-dependent Boltzman transport equation for thermal neutrons near a temperature discontinuity. The medium is nonabsorbing and infinite in extent. The method of solution consists of expanding the energy-transfer kernel in a degenerate form and then solving directly for the solutions of the resulting homogeneous equation. Both discrete and singular solutions are found. The angular flux is then expanded in terms of a complete set of these solutions. Finally, the expansion coefficients are determined by applying the boundary conditions associated with the temperature-discontinuity problem. Numerical calculations of both scalar neutron flux and total neutron density are included for various temperature ratios and neutron-to-moderator mass ratios. A comparison of the transport-theory results with diffusion-theory results shows that diffusion theory describes the neutron flux quite accurately for small values of temperature discontinuity. Diffusion-theory calculations become less accurate, however, as the higher energy modes become important. (Author)

Descriptors :   (*NEUTRON TRANSPORT THEORY, NUMERICAL ANALYSIS), INTEGRAL EQUATIONS, REACTOR MODERATORS, NEUTRON SCATTERING, NEUTRON CROSS SECTIONS, NEUTRON FLUX, THERMAL PROPERTIES

Subject Categories : Fission Reactor Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE