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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.
D. K. Olsen, G. de Saussure, R. B. Perez, E. G. Silver, F. C. Difilippo, R. W. Ingle, H. Weaver
Nuclear Science and Engineering | Volume 62 | Number 3 | March 1977 | Pages 479-501
Technical Paper | doi.org/10.13182/NSE77-A26986
Articles are hosted by Taylor and Francis Online.
The transmissions of 0.52- to 4000-eV neutrons through 3.62-, 1.08-, 0.254-, 0.0762-, 0.0254-, 0.0127-, and 0.0036-cm-thick samples of uranium, enriched in the 238U isotope, have been measured at 42 m with a 1.0-mm-thick 6Li glass detector using the Oak Ridge Electron Linear Accelerator pulsed neutron source. To obtain resonance parameters, the seven transmissions of neutrons having energies ranging from 0.52 to 1086.8 eV have been shape-fitted by least-squares analysis to a multilevel Breit-Wigner cross-section formalism with “picket-fence” terms to account for truncation effects. This simultaneous fit yielded a χ2 per degree of freedom near unity. Averaged over this energy range, an s-wave strength function of (0.968 ± 0.036) × 10-4 cm and an effective radius of (0.944 ± 0.005) × 10-12 cm were obtained. In addition, these transmission data yielded an average radiation width of 23.1 ±1.0 meV for the 12 lowest energy s-wave resonances with radiation widths of 23.0 ± 0.8, 22.8 ± 0.8, and 22.9 ± 0.8 meV for the 6.67-, 20.9-, and 36.8-eV resonances, respectively. The derived radiation widths for these three resonances are shown to depend on the cross-section formalism employed. This work suggests that a multilevel formalism with truncation compensation is required to adequately represent the 238U total cross section.