Development of a new two-dimensional Cartesian geometry nodal multigroup discrete ordinates method

Thesis/Dissertation · Fri Jan 01 04:00:00 EST 1982

OSTI ID:6297203

Pevey, R E

The purpose of this work is the development and testing of a new family of methods for calculating the spatial dependence of the neutron density in nuclear systems described in two-dimensional Cartesian geometry. The energy and angular dependence of the neutron density is approximated using the multigroup and discrete ordinates techniques respectively. 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. The three methods which were developed differ in the detail of the spatial description: (1) the first method expands the two-dimensional intranode neutron flux as two separable one-dimensional expansions in the x- and y-dimensions and represents the edge fluxes as constant; (2) the second method is the same as the first in the interior of each node, but represents the edge fluxes as one-dimensional expansions in the basis function set; and (3) the third method is the same as the second on the edges, but represents the interior flux shape in a full two-dimensional expansion in the x- and y-dependent basis functions. In order to test the accuracy versus computer time of the three methods, five sample problems were run and the results compared with those of the finite-difference code DOT4.2.

• Research Organization: Tennessee Univ., Knoxville (USA)
• OSTI ID: 6297203
• Country of Publication: United States
• Language: English

Related Subjects

654003* -- Radiation & Shielding Physics-- Neutron Interactions with Matter
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ANGULAR DISTRIBUTION
COMPUTER CODES
D CODES
DENSITY
DISCRETE ORDINATE METHOD
DISTRIBUTION
ENERGY
NEUTRAL-PARTICLE TRANSPORT
NEUTRON TRANSPORT
PHYSICAL PROPERTIES
RADIATION TRANSPORT
SPATIAL DISTRIBUTION
TWO-DIMENSIONAL CALCULATIONS