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EXTREME: a new two-dimensional Cartestian-geometry discrete-ordinates method

Conference ·
OSTI ID:6234882
The purpose of this work is the development and testing of EXTREME, a new method for calculating the spatial dependence of the neutron density in nuclear systems described in two-dimensional Cartesian geometry. The energy dependence of the neutron density is approximated using the multipgroup treatment; the angular dependence uses the discrete ordinates technique. The resulting FORTRAN computer code is designed to handle an arbitrary number of spatial, energy, and angle subdivisions. Any degree of scattering anisotropy can be handled by the code for either external source or fission systems. The basic approach is to (1) approximate the spatial variation of the neutron source across each spatial subdivision as an expansion in terms of a user-supplied set of exponential basis functions; (2) solve analytically for the resulting neutron density inside each region; and (3) approximate this density in the basis function space in order to calculate the next iteration flux-dependent source terms. In the general case the calculation is iterative due to neutron sources which depend on the neutron density itself, such as scattering interactions.
Research Organization:
Du Pont de Nemours (E.I.) and Co., Aiken, SC (USA). Savannah River Lab.; Tennessee Univ., Knoxville (USA). Dept. of Nuclear Engineering
DOE Contract Number:
AC09-76SR00001
OSTI ID:
6234882
Report Number(s):
DP-MS-83-2; CONF-830304-21; ON: DE83011634
Country of Publication:
United States
Language:
English