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Fusion Science and Technology
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Latest News
Modernizing I&C for operations and maintenance, one phase at a time
The two reactors at Dominion Energy’s Surry plant are among the oldest in the U.S. nuclear fleet. Yet when the plant celebrated its 50th anniversary in 2023, staff could raise a toast to the future. Surry was one of the first plants to file a subsequent license renewal (SLR) application, and in May 2021, it became official: the plant was licensed to operate for a full 80 years, extending its reactors’ lifespans into 2052 and 2053.
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.
