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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.
R. L. French and M. B. Wells
Nuclear Science and Engineering | Volume 19 | Number 4 | August 1964 | Pages 441-448
Technical Paper | doi.org/10.13182/NSE64-A19002
Articles are hosted by Taylor and Francis Online.
An albedo model for calculating the dose due to fast neutrons reflected from materials of low to moderate hydrogen content has been developed through analysis of extensive Monte Carlo data. The model, which was developed from reflection data for iron, concrete and three types of soil, is for reflection to a unit non-directional receiver and is of the form α(Ε0)cos2-3θ0cosθ where α(Ε0) is a coefficient tabulated as a function of incident energy, Ε0, for the various materials, θ0 is the angle of incidence and θ is the angle of reflection (both measured from the normal). The differential albedo, in units of reflected dose/steradian per unit dose incident at angle θ0, may be converted to a total albedo by multiplying by π. The total dose albedo for normally incident fission neutron was found to be closely approximated by 0.435(ΣΤΣΗ)/ΣΤ where ΣΤ is the macroscopic total cross section of all elements of the material, and ΣΗ is the macroscopic cross section of the hydrogen of the material, both weighted by the fission spectrum.