ANS is committed to advancing, fostering, and promoting the development and application of nuclear sciences and technologies to benefit society.
Explore the many uses for nuclear science and its impact on energy, the environment, healthcare, food, and more.
Explore membership for yourself or for your organization.
Conference Spotlight
2026 Nuclear Energy Conference & Expo (NECX)
August 24–27, 2026
Dallas, TX|Hilton Anatole
Latest Magazine Issues
Jul 2026
Jan 2026
2026
Latest Journal Issues
Nuclear Science and Engineering
August 2026
Nuclear Technology
July 2026
Fusion Science and Technology
Latest News
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.
L. Green, J. A. Mitchell, N. M. Steen
Nuclear Science and Engineering | Volume 50 | Number 3 | March 1973 | Pages 257-272
Technical Paper | doi.org/10.13182/NSE73-A28979
Articles are hosted by Taylor and Francis Online.
The 252Cf prompt-fission-neutron spectrum has been measured by time-of-flight techniques over the energy range 0.5 to 13 MeV. Significant analytical and experimental improvements over earlier measurements were employed. The data were simultaneously analyzed with the angular pattern data of Bowman et al., using a model which includes anisotropy of emission in the neutron fragment coordinate system and a stationary source. Based on this analysis, the mean energy is found to be 2.105 ± 0.014 MeV. It is also concluded that the fragment emission spectra are highly anisotropic. The anisotropy is dictated by the data presented here, rather than by angular patterns. The existence of the stationary source is supported by both data types. A Maxwellian fit to the data provided a temperature parameter of 1.406 ± 0.015 MeV. While the spectrum clearly deviates from a Maxwellian, this simple representation was found to be adequate to ±5% from 0.7 to 8.0 MeV.