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.
E. T. Tomlinson, J. C. Robinson
Nuclear Science and Engineering | Volume 63 | Number 2 | June 1977 | Pages 167-178
Technical Paper | doi.org/10.13182/NSE77-A27020
Articles are hosted by Taylor and Francis Online.
A method is developed for obtaining solutions to the Boltzmann neutron transport equation on irregular triangular grids with nonorthogonal boundaries and anisotropic scattering. A functional is developed from the canonical form of the multigroup transport equation. The angular variable is then removed by expanding the functional in spherical harmonics, retaining only the first two flux moments and limiting the scattering to be linearly anisotropic. The finite element method is then implemented using quadratic Lagrange-type interpolating polynomials to span the spatial domain. The resultant set of coupled linear equations is then solved iteratively using the block successive over-relaxation method. A number of numerical experiments are performed to evaluate the performance of the proposed method. The results are compared to the results obtained by various established methods. In all cases, aggrement is excellent.