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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.
S. Langenbuch, W. Maurer, W. Werner
Nuclear Science and Engineering | Volume 63 | Number 4 | August 1977 | Pages 437-456
Technical Paper | doi.org/10.13182/NSE77-A27061
Articles are hosted by Taylor and Francis Online.
A coarse-mesh method for the solution of multidimensional neutron kinetics problems is presented that is based on the approximation of the desired solution by basis functions with local nonoverlapping supports corresponding to the volume elements of the spatial mesh. Integration of the approximating functions over their supports, and exploitation of continuity conditions for neutron flux and current, yields local seven-point difference operators with solution-dependent coupling coefficients. Due to the finite-difference (FD) structure of the resulting matrix equation, any technique developed for FD methods can be used for its solution. However, a novel (“almost implicit”) alternating direction explicit-implicit technique has been developed that is especially suited for coarse-mesh applications. Numerical examples that demonstrate the high efficiency of the method are presented. By using a spatial grid corresponding to the fuel element structure, it is possible to compute power distribution and its time history very accurately (at most, with a several percent error) at an economically tolerable expense.