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Fusion Science and Technology
Latest News
In transition: Commercializing fusion power
Commercial fusion power is closer than ever. There are now around 30 U.S. fusion companies, several of which claim to be on track to connect to the grid as early as the 2030s.
Tokamak and laser inertial confinement approaches benefit from decades of research at facilities such as the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory and ITER, with alternative concepts including stellarator, magnetic mirror, and Z-pinch confinement also making notable progress as private and government funding for fusion increases.
J. E. Morel, K. D. Lathrop
Nuclear Science and Engineering | Volume 147 | Number 2 | June 2004 | Pages 158-166
Technical Paper | doi.org/10.13182/NSE04-A2425
Articles are hosted by Taylor and Francis Online.
The integral transport equation clearly indicates that the angular flux in a void is constant along each characteristic. Yet, simple arguments can be used to demonstrate that there exist angular flux solutions in voids that have a delta-function angular dependence and a nonconstant spatial dependence. Such solutions can appear to be nonconstant along a characteristic. Using a simple example problem, we demonstrate that such solutions represent the limit of a continuous sequence of nonsingular solutions, each of which is constant along every characteristic. We also show that care must be taken in applying the integral transport equation to singular problems of this type because erroneous solutions are easily obtained. Two reliable approaches for obtaining proper solutions are presented. We also show that the differential form of the transport equation in one-dimensional spherical geometry requires less care than the integral form of the transport equation for problems of this type. Finally, we discuss the applicability of the Sn method to problems in curvilinear geometries with singular solutions of this type.