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
Mar 2026
Jul 2025
Latest Journal Issues
Nuclear Science and Engineering
March 2026
Nuclear Technology
February 2026
Fusion Science and Technology
April 2026
Latest News
NRC approves TerraPower construction permit
Today, the Nuclear Regulatory Commission announced that it has approved TerraPower’s construction permit application for Kemmerer Unit 1, the company’s first deployment of Natrium, its flagship sodium fast reactor.
This approval is a significant milestone on three fronts. For TerraPower, it represents another step forward in demonstrating its technology. For the Department of Energy, it reflects progress (despite delays) for the Advanced Reactor Demonstration Program (ARDP). For the NRC, it is the first approval granted to a commercial reactor in nearly a decade—and the first approval of a commercial non–light water reactor in more than 40 years.
Naeem M. Abdurrahman, Georgeta Radulescu, Igor Carron
Nuclear Technology | Volume 127 | Number 3 | September 1999 | Pages 315-331
Technical Paper | Reactor Safety | doi.org/10.13182/NT99-A3004
Articles are hosted by Taylor and Francis Online.
The Saxton critical experiments, which used mixed-oxide (MOX) fuel of 6.6 wt% PuO2 in natural UO2 and UO2 fuel of 5.74 wt% 235U, are analyzed with MCNP-4B and continuous-energy cross-section libraries ENDF/B-V and ENDF/B-VI. An excellent agreement of calculated and experimental effective multiplication factors for the entire set of 1.3208-cm MOX lattices and 1.4224-cm MOX and UO2 lattices was obtained. The analysis of criticality calculations for the five different lattice pitches show a bias with lattice pitch, which led to an increase of ~0.8% when doubling the lattice pitch. Good agreement between calculated and measured data was obtained for some of the relative power distribution experiments for MOX single-region cores and MOX/UO2 multiregion cores; however, for others the agreement was less satisfactory. No significant difference in the results for relative power with the two libraries was observed.
