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The deadline arrives: Checking in on the Reactor Pilot Program
On May 23, 2025, President Trump signed Executive Order 14301, “Reforming Nuclear Reactor Testing at the DOE,” which instructed the Department of Energy to create a Reactor Pilot Program (RPP)—a new system in which companies could pursue DOE authorization to build and test their first-of-a-kind nuclear technologies. EO 14301 set an ambitious goal for that program: three reactors achieving criticality by July 4, 2026.
Young Ryong Park, Nam Zin Cho
Nuclear Science and Engineering | Volume 158 | Number 2 | February 2008 | Pages 154-163
Technical Paper | doi.org/10.13182/NSE06-23
Articles are hosted by Taylor and Francis Online.
As the nuclear reactor core becomes more complex, heterogeneous, and geometrically irregular, the method of characteristics (MOC) is gaining popularity in neutron transport calculations. However, the long computing times require good acceleration methods. In this paper, the concept of coarse-mesh angular dependent rebalance (CMADR) acceleration is described and applied to the MOC calculation in x-y geometry. The method is based on the angular-dependent rebalance factors defined on coarse-mesh cell boundaries. A coarse-mesh cell may consist of several fine-mesh cells that can be heterogeneous and of mixed geometries with irregular or unstructured mesh shapes. The CMADR acceleration is tested on several test problems, including problems with strong material heterogeneity, and the results show that CMADR is very effective in reducing the number of iterations and the computing times of MOC calculations.