Nodal methods for discrete-ordinates transport problems in (x,y) geometry

Conference · Thu Jan 01 04:00:00 EST 1981

OSTI ID:6673085

Walters, W F; O'Dell, R D

A nodal method has been developed for improved spatial differencing of the discrete-ordinates form of the x,y geometry transport equation. In applying this method, spatial flux expansions are assumed along the edges of each solution node (mesh cell), and flux and source expansions are assumed in the interior of the node. Nodal method schemes are thus identified by the expansions used for node edges and node interior. Nodal schemes assuming constant-constant, constant-linear, and four forms of linear-linear expansion have been developed, programed, and used in the analysis of eigenvalue (k/sub eff/) and shielding problems. Nodal results are compared with those obtained by means of the diamond-difference scheme. On the basis of results of eigenvalue test problems examined by the authors, it appears that the linear-linear nodal method schemes are more cost effective than the diamond-difference scheme for eigenvalue (k/sub eff/) problems. These nodal schemes, although more computationally costly than the diamond scheme per mesh cell, yield results of comparable accuracy to those from diamond with far fewer mesh cells. A net savings in both computer time and storage is obtained with the nodal schemes when compared with the diamond scheme for the same accuracy of results. For shielding problems both the constant-linear and linear-linear nodal schemes are superior to the diamond scheme in the sense of reduced computer time and storage for the same accuracy in results. 2 figures, 2 tables.

• Research Organization: Los Alamos National Lab., NM (USA)
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 6673085
• Report Number(s): LA-UR-81-100; CONF-810415-1
• Country of Publication: United States
• Language: English

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73 NUCLEAR PHYSICS AND RADIATION PHYSICS
COMPARATIVE EVALUATIONS
COMPUTER CALCULATIONS
DISCRETE ORDINATE METHOD
EIGENVALUES
ELEMENTS
EXPERIMENTAL REACTORS
HYDROGEN COMPOUNDS
IRON
METALS
MULTIGROUP THEORY
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OXYGEN COMPOUNDS
RADIATION TRANSPORT
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RESEARCH AND TEST REACTORS
SHIELDING
TRANSITION ELEMENTS
TRANSPORT THEORY
TWO-DIMENSIONAL CALCULATIONS
WATER
ZERO POWER REACTORS