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
Jun 2026
Jan 2026
2026
Latest Journal Issues
Nuclear Science and Engineering
July 2026
Nuclear Technology
June 2026
Fusion Science and Technology
May 2026
Latest News
Antares achieves zero-power criticality at INL
Leveraging more than $140 million in private capital fundraising, over 322,000 square feet of operational manufacturing space, and multifaceted partnerships with the Departments of Energy and Defense, reactor start-up Antares has become the first company involved in the Reactor Pilot Program to achieve zero-power fueled criticality—a full month ahead of the July 4 deadline set by President Trump’s Executive Order 14301.
This milestone, announced yesterday, was achieved with the company’s Mark-0: a sodium heat-pipe-cooled, TRISO-fueled microreactor. The Mark-0 is a forerunner to the company’s flagship design, which it calls the R1. For Antares, this development represents a key validation of its reactor physics, control systems, and supply chain.
Kun Jie Yang, Yue-Lin Liu, Ning Liu, Peng Shao, Xu Zhang, Yuming Ma
Fusion Science and Technology | Volume 76 | Number 5 | July 2020 | Pages 616-631
Technical Paper | doi.org/10.1080/15361055.2020.1740556
Articles are hosted by Taylor and Francis Online.
We performed systematically first-principles calculations to investigate interstitial H diffusion/permeation of temperature dependence in tungsten (W). The interstitial H diffusion is primarily through two nearest-neighbor tetrahedral positions and its activation energy increases significantly with rising temperature. Phonon vibration plays a decisive role in the behavior of the H activation energy with rising temperature. The H permeation activation energy also depends strongly on the temperature since it is the sum of the formation energy and diffusion activation energy of H. Our calculated H diffusivity/permeability with the temperature agree quantitatively with the reliable experimental data within the error range in W. The vacancy-capturing effect can give a reasonable explanation of the discrepancy between simulation and experiment. Although the diffusion/permeation activation energy and the prefactor strongly depend on the temperature, the diffusivity/permeability of H still obeys quasi-Arrhenius behavior with rising temperature, which is attributed to the compensation effect between the activation energy and the prefactor, i.e., the increment of the prefactor compensates directly the modification of the diffusivity/permeability in the case of a variation in the activation energy with rising temperature.