MIST (MULTIGROUP INTERNUCLEAR SLAB TRANSPORT)

Technical Report · Fri Aug 18 04:00:00 EDT 1961

OSTI ID:4799584

Putnam, G E; Shapiro, D M

A description is given of a set of codes designed to solve the one- dimensional Boltzmann equation in slab geometry for up to six energy groups, two hundred and fifty space points and forty regions. The boundary conditions for each group can be independently specified and the boundary conditions permit very general specifications with regard to: perfect mirror reflection or symmetry, anisotropic diIfuse sources (by input of Legendre polynomial coefficients or a short table describing a known angular distribution of the flux), and isotropic (Lambert surface) reflection. lndependent specification of an isotropic volume source in each group is also allowed. Although scattering from one group to another is assumed to be isotropic, the scattering function within each group can be a second order Legendre polynomial series. The method used to solve for the angular dependent flux in each group is not iterative; hence, few group problems require no more than a few outer iterations. The numerical approximation to the Boltzmann equation is a linear one which can be described as an extension and generalization of methods used in the original Sn codes. The physically unrealistic non symmetrical nature of the former Sn approximation in slab cases with regard to fluxes in -he forward and backward hemispheres was removed. rhe MIST program is the first application of the new formulation with a noniterative method of solution for the fluxes in each energy group of a slab geometry model. The coupling of the groups is by way of downscattering and fission. The program is divided into four separate codes in order to provide the maximum number of space points for each order of tire angular approximation. The limits on the number of mesh points in each code are given. The MIST program is presently written for an IBM 7090 with 32K storage. It is in the FORTRAN language which allows for relatively easy modification and adaptation to other computing systems. (auth)

• Research Organization: Internuclear Co., Inc., Clayton, Mo.
• NSA Number: NSA-16-033984
• OSTI ID: 4799584
• Report Number(s): INTERNUC-67
• Country of Publication: United States
• Language: English

Related Subjects

ANGULAR DISTRIBUTION
BOLTZMANN EQUATION
BOUNDARY CONDITIONS
COMPUTERS
CONFIGURATION
DIFFERENTIAL EQUATIONS
DIFFUSION
DISTRIBUTION
FISSION
GROUP THEORY
MATHEMATICS
NEUTRON FLUX
NEUTRON SOURCES
NEUTRONS
NUMERICALS
PLATES
PROGRAMMING
REACTOR CORE
REACTOR TECHNOLOGY
REACTORS
REFLECTORS
SCATTERING
VOLUME
ZONES