Computational Modeling of a Time-Independent, Heterogeneous Reactor Core Using Simplified Discrete Ordinates Neutron Transport Techniques
Abstract
The Linear Characteristic (LC) method on rectangular boxoid meshes is a discrete ordinate neutron transport technique that uses both zeroth and first moments of the angular neutron flux to construct a relatively accurate representation of neutron particle distributions in a given medium. The significant number of calculations required by LC when compared to more conventional methods such as Diamond Difference vastly increases computational time by a factor of 60 (or minutes to hours). A modified extrapolation, linear acceleration method with iterative shooting capability was adapted along with approximated initial guesses to the scalar flux to effectively reduce LC computational times by as much as 70% to 90%. Unlike conventional methods that contain instabilities and errors that are accentuated and magnified at optically thick boundaries, the LC method calculated stable consistent flux results through boundary regions of varying absorptive materials. The inherently computationally intensive linear algebra used by the LC method was simplified using FORTRAN 90/95 programming commands designed to optimize vector and matrix calculations and reduce and simplify the overall source code.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 2001
- Accession Number
- ADA396827
Entities
People
- Kristofer S. Labowski
Organizations
- Air Force Institute of Technology