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Title: Multilevel acceleration of scattering-source iterations with application to electron transport

Acceleration/preconditioning strategies available in the SCEPTRE radiation transport code are described. A flexible transport synthetic acceleration (TSA) algorithm that uses a low-order discrete-ordinates (S N) or spherical-harmonics (P N) solve to accelerate convergence of a high-order S N source-iteration (SI) solve is described. Convergence of the low-order solves can be further accelerated by applying off-the-shelf incomplete-factorization or algebraic-multigrid methods. Also available is an algorithm that uses a generalized minimum residual (GMRES) iterative method rather than SI for convergence, using a parallel sweep-based solver to build up a Krylov subspace. TSA has been applied as a preconditioner to accelerate the convergence of the GMRES iterations. The methods are applied to several problems involving electron transport and problems with artificial cross sections with large scattering ratios. These methods were compared and evaluated by considering material discontinuities and scattering anisotropy. Observed accelerations obtained are highly problem dependent, but speedup factors around 10 have been observed in typical applications.
Authors:
 [1] ;  [1]
  1. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Publication Date:
Report Number(s):
SAND-2017-6703J
Journal ID: ISSN 1738-5733; PII: S1738573317303066
Grant/Contract Number:
AC04-94AL85000
Type:
Accepted Manuscript
Journal Name:
Nuclear Engineering and Technology
Additional Journal Information:
Journal Volume: 49; Journal Issue: 6; Journal ID: ISSN 1738-5733
Publisher:
Korean Nuclear Society
Research Org:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Sponsoring Org:
USDOE National Nuclear Security Administration (NNSA)
Country of Publication:
United States
Language:
English
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
OSTI Identifier:
1399506

Drumm, Clif, and Fan, Wesley. Multilevel acceleration of scattering-source iterations with application to electron transport. United States: N. p., Web. doi:10.1016/j.net.2017.08.009.
Drumm, Clif, & Fan, Wesley. Multilevel acceleration of scattering-source iterations with application to electron transport. United States. doi:10.1016/j.net.2017.08.009.
Drumm, Clif, and Fan, Wesley. 2017. "Multilevel acceleration of scattering-source iterations with application to electron transport". United States. doi:10.1016/j.net.2017.08.009. https://www.osti.gov/servlets/purl/1399506.
@article{osti_1399506,
title = {Multilevel acceleration of scattering-source iterations with application to electron transport},
author = {Drumm, Clif and Fan, Wesley},
abstractNote = {Acceleration/preconditioning strategies available in the SCEPTRE radiation transport code are described. A flexible transport synthetic acceleration (TSA) algorithm that uses a low-order discrete-ordinates (SN) or spherical-harmonics (PN) solve to accelerate convergence of a high-order SN source-iteration (SI) solve is described. Convergence of the low-order solves can be further accelerated by applying off-the-shelf incomplete-factorization or algebraic-multigrid methods. Also available is an algorithm that uses a generalized minimum residual (GMRES) iterative method rather than SI for convergence, using a parallel sweep-based solver to build up a Krylov subspace. TSA has been applied as a preconditioner to accelerate the convergence of the GMRES iterations. The methods are applied to several problems involving electron transport and problems with artificial cross sections with large scattering ratios. These methods were compared and evaluated by considering material discontinuities and scattering anisotropy. Observed accelerations obtained are highly problem dependent, but speedup factors around 10 have been observed in typical applications.},
doi = {10.1016/j.net.2017.08.009},
journal = {Nuclear Engineering and Technology},
number = 6,
volume = 49,
place = {United States},
year = {2017},
month = {8}
}