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Development and Evaluation of High-Fidelity Product and Evenly Spaced Angular Quadratures for Three-Dimensional Discrete Ordinates Calculations with Large Air Regions

Daniel B. Fromowitz, Gary B. Zeigler

Nuclear Science and Engineering / Volume 182 / Number 2 / February 2016 / Pages 166-180

Technical Paper /

First Online Publication:January 15, 2016
Updated:February 2, 2016

Using two different methods, angular quadrature sets are developed with greater than about 1000 angles per octant to reduce ray effects in three-dimensional (3-D), discrete ordinates radiation transport calculations with large air or void regions. Quadrature sets from both methods are evaluated in two distinct 3-D models sensitive to quadrature details and are shown to behave reasonably well. The first method is a previously described method that is examined here in 3-D. The second method produces quadrature sets that have quadrature directions approximately evenly spaced over the entire surface of the unit sphere.