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Fixing the barriers: How new policies can make U.S. nuclear exports competitive again
The United States has a strong marketplace of ideas on future civil nuclear technology. President Trump wants to see 10 large reactors under construction by 2030 and has discussed making $80 billion available for that objective. Evolutionary small modular reactors based on light water reactor technology are on the market now, and the Tennessee Valley Authority expects a construction permit for a project at its Clinch River Site later this year.
Bilge Ozgener
Fusion Science and Technology | Volume 61 | Number 1 | January 2012 | Pages 308-313
Modeling and Simulations | Proceedings of the Fifteenth International Conference on Emerging Nuclear Energy Systems | doi.org/10.13182/FST12-A13438
Articles are hosted by Taylor and Francis Online.
Discrete ordinates solutions of the neutron transport equation require the solution of the within-group transport equation by the method of iteration on the scattering source. Scattering source iterations are hampered by extremely slow convergence rates when the medium is highly scattering. Among the methods proposed for the acceleration of the scattering source iterations, the coarse mesh rebalance and the diffusion synthetic acceleration techniques appear to be the most prominent ones. Thus, one or the other has been adopted in most of the SN codes. The numerical studies concerning the effectiveness of these acceleration methods have been made mostly for the planar geometry. There are some studies also for the multidimensional Cartesian geometries. In this study we have tried to assess the merits of these acceleration techniques in a curvilinear coordinate system that is spherical geometry. The performance of both of the acceleration methods have been determined by varying the scattering to total cross section ratio, the mesh size, the degree of anisotropy in scattering for a uniform spherical system. Then the study is extended to multiregion systems some of which are diffusive and in some of which transport effects are important.