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.
Yoshinori Miyoshi, Takuya Umano, Kotaro Tonoike, Naoki Izawa, Susumu Sugikawa, Shuji Okazaki
Nuclear Technology | Volume 118 | Number 1 | April 1997 | Pages 69-82
Technical Paper | Kiyose Birthday Anniversary Special / Nuclear Criticality Safety | doi.org/10.13182/NT97-A35358
Articles are hosted by Taylor and Francis Online.
A series of critical experiments with 10% enriched uranyl nitrate solution using a cylindrical core tank 60 cm in diameter have been performed with the Static Experiment Critical Facility at the Nuclear Fuel Cycle Safety Engineering Research Facility in the Tokai research establishment of the Japan Atomic Energy Research Institute. In the first series of experiments using the cylindrical core tank, systematic data of the critical height for water-reflected cores and unreflected cores were obtained by changing the uranium concentration of the fuel solution from 313 to 225 g U/ℓ. As the reactivity of each core is controlled only by solution height, these criticality configurations, which have simple cylindrical shapes, are available for the validation of calculation codes used in criticality safety designs of nuclear fuel cycle facilities. The neutron multiplication factors of experimental cores were calculated with the two-dimensional transport code TWOTRAN in the SRAC code system and with the continuous-energy Monte Carlo code MCNP4A, employing the Japanese evaluated nuclear data library JENDL-3.2. The calculations from the combination of these calculation codes and the nuclear data library reproduce the neutron multiplication factors within an error of 0.9% for the experimental configuration of critical cores.