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.
J. C. Young, G. D. Trimble, Y. D. Naliboff, D. H. Houston, J. R. Beyster
Nuclear Science and Engineering | Volume 18 | Number 3 | March 1964 | Pages 376-399
Technical Paper | doi.org/10.13182/NSE64-A20058
Articles are hosted by Taylor and Francis Online.
Neutron-spectrum measurements in several moderators have been made with geometrical conditions approximating an infinite medium. The moderators studied were water, polyethylene and benzene, and the absorbers dispersed in the moderators were boron, samarium, erbium and gadolinium. The measurements are compared with predictions of the neutron spectra utilizing scattering models which take into consideration chemical binding. Measurements of scalar and angular neutron-energy spectra were made in a slab geometry water-moderated multiplying assembly at room temperature. The measured spectra are compared with DSN transport-theory calculations utilizing the Nelkin bound-hydrogen scattering model for water.