skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: A new approach to three-dimensional neutron transport solution based on the method of characteristics and linear axial approximation

Abstract

A new approach based on the method of characteristics (MOC) is proposed to solve the neutron transport equation. A new three-dimensional (3D) spatial discretization is applied to avoid the instability issue of the transverse leakage iteration of the traditional 2D/1D approach. In this new approach, the axial and radial variables are discretized in two different ways: the linear expansion is performed in the axial direction, then, the 3D solution of the angular flux is transformed to be the planar solution of 2D angular expansion moments, which are solved by the planar MOC sweeping. Based on the boundary and interface continuity conditions, the 2D expansion moment solution is equivalently transformed to be the solution of the axially averaged angular flux. Using the piecewise averaged angular flux at the top and bottom surfaces of 3D meshes, the planes are coupled to give the 3D angular flux distribution. The 3D CMFD linear system is established from the surface net current of every 3D pin-mesh to accelerate the convergence of power iteration. The STREAM code is extended to be capable of handling 3D problems based on the new approach. Several benchmarks are tested to verify its feasibility and accuracy, including the 3D homogeneous benchmarksmore » and heterogeneous benchmarks. The computational sensitivity is discussed. The results show good accuracy in all tests. With the CMFD acceleration, the convergence is stable. In addition, a pin-cell problem with void gap is calculated. This shows the advantage compared to the traditional 2D/1D MOC methods.« less

Authors:
 [1];  [2];  [3];  [3]
  1. Xi'an Jiaotong University, No. 28, Xianning West Road, Xi'an, Shaanxi 710049 (China)
  2. (Korea, Republic of)
  3. Ulsan National Institute of Science and Technology, UNIST-gil 50, Ulsan 689-798 (Korea, Republic of)
Publication Date:
OSTI Identifier:
22701632
Resource Type:
Journal Article
Journal Name:
Journal of Computational Physics
Additional Journal Information:
Journal Volume: 350; Other Information: Copyright (c) 2017 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0021-9991
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ANGULAR DISTRIBUTION; BENCHMARKS; MATHEMATICAL SOLUTIONS; MOLYBDENUM CARBIDES; NEUTRON TRANSPORT THEORY; THREE-DIMENSIONAL CALCULATIONS; THREE-DIMENSIONAL LATTICES

Citation Formats

Zheng, Youqi, Ulsan National Institute of Science and Technology, UNIST-gil 50, Ulsan 689-798, Choi, Sooyoung, and Lee, Deokjung. A new approach to three-dimensional neutron transport solution based on the method of characteristics and linear axial approximation. United States: N. p., 2017. Web. doi:10.1016/J.JCP.2017.08.026.
Zheng, Youqi, Ulsan National Institute of Science and Technology, UNIST-gil 50, Ulsan 689-798, Choi, Sooyoung, & Lee, Deokjung. A new approach to three-dimensional neutron transport solution based on the method of characteristics and linear axial approximation. United States. doi:10.1016/J.JCP.2017.08.026.
Zheng, Youqi, Ulsan National Institute of Science and Technology, UNIST-gil 50, Ulsan 689-798, Choi, Sooyoung, and Lee, Deokjung. Fri . "A new approach to three-dimensional neutron transport solution based on the method of characteristics and linear axial approximation". United States. doi:10.1016/J.JCP.2017.08.026.
@article{osti_22701632,
title = {A new approach to three-dimensional neutron transport solution based on the method of characteristics and linear axial approximation},
author = {Zheng, Youqi and Ulsan National Institute of Science and Technology, UNIST-gil 50, Ulsan 689-798 and Choi, Sooyoung and Lee, Deokjung},
abstractNote = {A new approach based on the method of characteristics (MOC) is proposed to solve the neutron transport equation. A new three-dimensional (3D) spatial discretization is applied to avoid the instability issue of the transverse leakage iteration of the traditional 2D/1D approach. In this new approach, the axial and radial variables are discretized in two different ways: the linear expansion is performed in the axial direction, then, the 3D solution of the angular flux is transformed to be the planar solution of 2D angular expansion moments, which are solved by the planar MOC sweeping. Based on the boundary and interface continuity conditions, the 2D expansion moment solution is equivalently transformed to be the solution of the axially averaged angular flux. Using the piecewise averaged angular flux at the top and bottom surfaces of 3D meshes, the planes are coupled to give the 3D angular flux distribution. The 3D CMFD linear system is established from the surface net current of every 3D pin-mesh to accelerate the convergence of power iteration. The STREAM code is extended to be capable of handling 3D problems based on the new approach. Several benchmarks are tested to verify its feasibility and accuracy, including the 3D homogeneous benchmarks and heterogeneous benchmarks. The computational sensitivity is discussed. The results show good accuracy in all tests. With the CMFD acceleration, the convergence is stable. In addition, a pin-cell problem with void gap is calculated. This shows the advantage compared to the traditional 2D/1D MOC methods.},
doi = {10.1016/J.JCP.2017.08.026},
journal = {Journal of Computational Physics},
issn = {0021-9991},
number = ,
volume = 350,
place = {United States},
year = {2017},
month = {12}
}