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 ANS Annual Conference
May 31–June 3, 2026
Denver, CO|Sheraton Denver
Latest Magazine Issues
Feb 2026
Jul 2025
Latest Journal Issues
Nuclear Science and Engineering
March 2026
Nuclear Technology
February 2026
Fusion Science and Technology
January 2026
Latest News
NRC grants license for TRISO-X fuel manufacturing using HALEU
The Nuclear Regulatory Commission has granted X-energy subsidiary TRISO-X a special nuclear material license for high-assay low-enriched uranium fuel fabrication. The license applies to TRISO-X’s first two planned commercial facilities, known as TX-1 and TX-2, for an initial 40-year period. The facilities are set to be the first new nuclear fuel fabrication plants licensed by the NRC in more than 50 years.
Jeffrey A. Favorite
Nuclear Science and Engineering | Volume 175 | Number 1 | September 2013 | Pages 44-69
Technical Paper | doi.org/10.13182/NSE12-17
Articles are hosted by Taylor and Francis Online.
It is often desirable to solve radiation transport problems in one-dimensional spherical geometries even if the actual object being modeled is not spherical. It may be possible to use perturbation theory to account for the difference between the real multidimensional system and the spherical approximation. This idea is tested using uncollided as well as multigroup inhomogeneous transport problems with upscattering. Asymmetric and nonuniform perturbations are made to the shielding (not the source) of spherical geometries, including transformations from a sphere to a cube (the surface transformation function is derived), and Schwinger, Roussopolos, and combined perturbation estimates are applied. For uncollided fluxes, perturbation theory, particularly the Schwinger estimate, worked very well when the response of interest was the flux measured at a symmetric spherical 4 detector external to the geometry, but perturbation theory did not work well when the response of interest was the flux measured at a single external point (unless extra care was taken to account for geometric effects). For neutron-induced gamma-ray line fluxes, the Roussopolos estimate worked well when the response of interest was the flux measured at an external 4 detector or an external point detector.