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.
William H. Miller, Walter Meyer, Darrol H. Timmons
Nuclear Science and Engineering | Volume 62 | Number 2 | February 1977 | Pages 262-269
Technical Paper | doi.org/10.13182/NSE77-A26961
Articles are hosted by Taylor and Francis Online.
Fast-neutron angular penetration spectra were experimentally determined for a fast-neutron spectrum incident on 4-, 8-, and 12-in. (102-, 203-, and 305-mm)-thick water slabs. The experimental spectra were compared with MORSE Monte Carlo calculations using readily available multigroup cross sections. The source of fast neutrons for the experimental study was the Missouri University Research Reactor; the incident and penetration neutron spectra were detected using a 2- X 2-in. (51- X 51-mm) NE-213 liquid scintillation spectrometer system. A comparison of the Monte Carlo and experimental results showed excellent agreement for all but the thickest slabs. All results showed similar trends and structure, and only for the 12-in. slab did the experimental and calculated result vary by as much as 40% for shallow angle penetrations. Integrated spectral results are generally within ±15% for all reported angles and thicknesses. A modification to the well-known MORSE code has been utilized to calculate group-to-group transfer probabilities for each of the experimental geometries. These probabilities have been converted to dose and are tabulated to permit calculation of the penetration dose for any incident neutron spectrum for the comprehensive set of angles considered in this work.