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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.
Ricardo C. De Barros, Edward W. Larsen
Nuclear Science and Engineering | Volume 111 | Number 1 | May 1992 | Pages 34-45
Technical Paper | doi.org/10.13182/NSE92-A23921
Articles are hosted by Taylor and Francis Online.
A new nodal method is developed for the solution of one-group discrete ordinates (SN) problems with linearly anisotropic scattering in x,y-geometry. In this method, the “spectral Green’s function” (SGF) scheme, originally developed for solving SN problems in slab geometry with no spatial truncation error, is generalized to solve the one-dimensional transverse-integrated SN nodal equations with the “constant” approximation for the transverse leakage terms. The resulting “SGF-constant nodal” (SGF-CN) method is more accurate than conventional coarse-mesh methods for deep penetration problems because it treats the scattering source terms implicitly and exactly; the only approximation involves the transverse leakage terms. In conventional SN nodal methods, the transverse leakage terms and scattering source are both approximated. We solve the SGF-CN equations using the one-node block inversion iterative scheme, which uses the best available estimates for the node-entering fluxes to evaluate the node-exiting fluxes in the directions that constitute the incoming fluxes for the adjacent nodes as the equations are swept across the system. Finally, we give numerical results that illustrate the accuracy of the SGF-CN method for coarse-mesh calculations.