scholarly journals Reactor cross-section sensitivity studies using transport theory

1974 ◽  
Author(s):  
E. M. Oblow
Keyword(s):  
Cross Section ◽  
Transport Theory ◽  
Sensitivity Studies ◽  
Reactor Cross Section

Prediction of Three-Dimensional Steady Incompressible Flows Using Body-Fitted Coordinates

1993 ◽  
Vol 115 (3) ◽  
pp. 457-462 ◽  
Author(s):  
P. Tamamidis ◽  
D. N. Assanis
Keyword(s):  
Cross Section ◽  
Incompressible Flows ◽  
Three Dimensional ◽  
Computational Time ◽  
Complex Geometries ◽  
Curved Duct ◽  
Sensitivity Studies ◽  
Simplec Algorithm ◽  
Volume Method ◽  
Strong Curvature

A finite-volume method for three-dimensional, steady, incompressible flows in complex geometries is presented. The method uses generalized Body-Fitted Coordinates to accurately take into account the shape of the boundary. A collocated scheme is employed, which uses the three covariant velocities and the pressure as main variables. Continuity is coupled with the momentum equations using the SIMPLEC algorithm. It is found that the SIMPLEC algorithm can provide savings in computational time of up to 40 percent compared to calculations with SIMPLE. Sensitivity studies are also performed to find optimum values of the underrelaxation parameters. The method is validated against experimental results for the case of the flow in a 90 deg curved duct of square cross-section and comparatively strong curvature. The application of the method to the prediction of flows in complex geometries is then illustrated.

Phonon Transport in Anisotropic Scattering Particulate Media

2003 ◽  
Vol 125 (6) ◽  
pp. 1156-1162 ◽  
Author(s):  
Ravi Prasher
Keyword(s):  
Cross Section ◽  
Acoustic Waves ◽  
Transport Theory ◽  
Mode Conversion ◽  
Anisotropic Scattering ◽  
Phonon Transport ◽  
Isotropic Scattering ◽  
Radiative Transport ◽  
Particulate Media ◽  
Transport Cross Section

Equation of phonon radiative transport (EPRT) is rewritten to include anisotropic scattering by a particulate media by including an acoustic phase function and an inscattering term which makes EPRT exactly same as equation of radiative transport (ERT). This formulation of EPRT is called generalized EPRT (GEPRT). It is shown that GEPRT reduces to EPRT for isotropic scattering and is totally consistent with phonon transport theory, showing that transport cross section is different from the scattering cross section. GEPRT leads to same formulation for transport cross section as given by phonon transport theory. However GEPRT shows that transport cross section formulations as described by phonon transport theory are only valid for acoustically thick medium. Transport cross section is different for the acoustically thin medium leading to the conclusion that mean free path (m.f.p) is size dependant. Finally calculations are performed for two types of scatterers for acoustic waves without mode conversion: (1) acoustically hard Rayleigh sphere; and (2) large sphere in the geometrical scattering regime. Results show that the scattering from these particles is highly anisotropic. It is also shown that for geometrical scattering case isotropic scattering leads to the conclusion of total internal reflection at the particle/medium interface.

scholarly journals FAST REACTOR CROSS-SECTION PROCESSING CODES - IS THERE A DOLLARS WORTH OF DIFFERENCE BETWEEN THEM?

1975 ◽  
pp. 468-490 ◽  
Author(s):  
C.R. Weisbin ◽  
N.M. Greene ◽  
H. Henryson ◽  
R.J. LaBauve ◽  
C. Durston ◽  
...  
Keyword(s):  
Cross Section ◽  
Fast Reactor ◽  
Reactor Cross Section

Phonon Transport in Anisotropic Scattering Particulate Media

2003 ◽  
Author(s):  
Ravi S. Prasher
Keyword(s):  
Cross Section ◽  
Acoustic Waves ◽  
Transport Theory ◽  
Mode Conversion ◽  
Anisotropic Scattering ◽  
Phonon Transport ◽  
Isotropic Scattering ◽  
Radiative Transport ◽  
Particulate Media ◽  
Transport Cross Section

Equation of phonon radiative transport (EPRT) is rewritten to include anisotropic scattering by a particulate media by including an acoustic phase function and an in-scattering term which makes EPRT exactly same as equation of radiative transport (ERT). This formulation of EPRT is called generalized EPRT (GEPRT). It is shown that GEPRT reduces to EPRT for isotropic scattering and is totally consistent with phonon transport theory, showing that transport cross section is different from the scattering cross section. GEPRT leads to same formulation for transport cross section as given by phonon transport theory. However GEPRT shows that transport cross section formulations as described by phonon transport theory are only valid for acoustically thick medium. Transport cross section is different for the acoustically thin medium leading to the conclusion that mean free path (m.f.p) is size dependant. Finally calculations are performed for two types of scatterers for acoustic waves without mode conversion: 1) Acoustically hard Rayleigh sphere 2) large sphere in the geometrical scattering regime. Results show that the scattering from these particles is highly anisotropic. It is also shown that for geometrical scattering case isotropic scattering leads to the conclusion of total internal reflection at the particle/medium interface.

ON THE CALCULATION OF THE FUNDAMENTAL MODE OF THE ONE-VELOCITY NEUTRON TRANSPORT OPERATOR

1967 ◽  
Vol 45 (12) ◽  
pp. 3793-3801
Author(s):  
N. K. Bansal ◽  
A. K. Ghatak
Keyword(s):  
Asymptotic Behavior ◽  
Cross Section ◽  
Fundamental Mode ◽  
Transport Theory ◽  
Neutron Transport ◽  
Anisotropic Scattering ◽  
Laboratory System ◽  
Neutron Pulse ◽  
The One ◽  
Pulsed Neutron

We report here some results on the asymptotic behavior of a neutron pulse injected into a slab using monoenergetic transport theory including the effects of the anisotropic scattering cross section in the laboratory system. The calculations were performed in the P1 and P3 approximations. These results are compared with the exact numerical calculations and with the recent pulsed neutron experiments in fast nonmultiplying nonmoderating assemblies where the decay of an essentially monoenergetic burst of neutrons is studied.

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