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Deployable Energy achieves criticality at INL
Ahead of the July 4 deadline set by President Trump in Executive Order 14301, the nuclear community has been following the developments of the Department of Energy’s Reactor Pilot Program, in which companies have been pursuing DOE authorization to build and test their first-of-a-kind nuclear technologies. The EO set an ambitious goal of three reactors achieving criticality by July 4, 2026.
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.