PASSAGE OF NEUTRONS IN A HETEROGENEOUS MEDIUM

Technical Report · Sat Oct 31 04:00:00 EST 1959

OSTI ID:4281071

Laletin, N I

The distribution of monoenergetic neutrons is considered in a two- component heterogeneous medium. One component is a periodic lattice consisting of arbitrary-shaped cylinders. The rest of the space is occupied by another component. It is assumed that there is no absorption throughout. The kinetic equation in the integral form (Peierls' equation) is then investigated for cases when the plane neutron source is arranged in parallel or perpendicular to the axis of the medium's symmetry. Formulas are obtained for effective diffusion coefficients. In the case of rods consisting of plates, formulas are given which help to obtain the effective diffusion coefficients for any plate thickness. In the case of rods in the form of circular cylinders, a formula is obtained for the neutron diffusion coefficient in a direction which is parallel to the axis of the medium symmetry, and another formula for a part of a diffusion different in a perpendicular direction. It is shown that the diffusion coefficient in the limit of thin plates and rods is identical for all directions and is equal to the diffusion coefficient for the homogeneous mixture. Furthermore, a medium with the presence of a small absorption and a multplying medium of sufficiently great dimensions are considered. Formulas of a general form are obtained for effective diffusion coefficients and neutron diffusion lengths. (auth)

• Research Organization: U.S.S.R.
• NSA Number: NSA-13-006933
• OSTI ID: 4281071
• Report Number(s): A/CONF.15/P/2189
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

ABSORPTION
CONFIGURATION
CYLINDERS
DIFFERENTIAL EQUATIONS
DIFFUSION
DIFFUSION LENGTH
DISTRIBUTION
HOMOGENEOUS REACTORS
NEUTRON SOURCES
NEUTRONS
PHYSICS AND MATHEMATICS
PLATES
RODS
THICKNESS