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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. A. Dupree, J. E. Morel
Nuclear Science and Engineering | Volume 78 | Number 3 | July 1981 | Pages 284-293
Technical Paper | doi.org/10.13182/NSE81-A20305
Articles are hosted by Taylor and Francis Online.
Adjoint transport calculations provide an efficient means for determining the response of various targets to external sources of radiation. In the present paper, the fission response of a small, cylindrically symmetric target to a plane-incident beam of neutrons is determined through three techniques: (a) a discrete summation using EQN quadratures, (b) a discrete summation using Lobatto quadratures, and (c) an exact integral of a spherical harmonic interpolation of EQN angular fluxes. To calculate the fission response of the sample target to a reasonable degree of accuracy, the first method requires the use of quadratures of order at least S16, while the second method requires only S8. The general utility of the third method is hampered by a rapid increase in complexity with increasing quadrature order; however, for the present example, in which a low-order quadrature solution provides reasonably accurate scalar fluxes, interpolation of S2 angular fluxes yielded a response of comparable accuracy to the S8 Lobatto solution.