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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, L. G. Mooney
Nuclear Science and Engineering | Volume 47 | Number 3 | March 1972 | Pages 375-380
Technical Note | doi.org/10.13182/NSE72-A22425
Articles are hosted by Taylor and Francis Online.
The “last-collision” method for computing the air-ground interface effect on scattered neutron intensity is extended to give the effect on the intensity within individual polar angle groups at a detector near the ground. The method yields angle-dependent perturbation factors which can be used to adjust infinite-air angle distributions to account for the presence of an air-ground interface, or to adjust angle distributions from one detector height to another. To determine the factors, a uniform scattering distribution in the air about the detector is assumed, and the fractional contribution from each last-collision center in the air is calculated. In addition, the fraction scattered directly to the detector from the ground surface is calculated using a simplified albedo model. An evaluation of the angle-dependent last-collision model indicated that the results of discrete ordinate calculations for infinite air could be modified to give relative polar angle distributions of the scattered neutron dose near the air-ground interface within 10 to 20% of those calculated directly for the air-over-ground case by the discrete ordinate method.