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Oxide dispersion strengthened (ODS) ferritic steels are perceived as the most promising structural materials for advanced fission- and future fusion-reactor applications owing to their excellent irradiation resistance and high-temperature mechanical properties. To understand the role of interfaces under irradiation, the first-principles calculations have been performed to investigate geometric, energetic and electronic properties of the {1 0 0}<1 0 0>Fe//{1 0 0}<1 0 0>Y 2 O 3 interface as well as their interaction with radiation point defects. For O monovacancy in the Y 2 O 3 layer, its formation energy slightly increases when it approaches to interface. For Fe monovacancy, the vacancy formation energy decreases when the vacancy is close to the interface. For Fe–Fe divacancies, the formation energy of the first nearest neighbor (1NN) and 2NN Fe–Fe divacancies at the interface are −9.48 eV and −10.49 eV, while their binding energies are −2.46 eV and −1.45 eV, respectively. These results suggest that the α-Fe/Y 2 O 3 interface tends to attract vacancies in Fe matrix, yet prevents to form voids at the interface, which enhances radiation resistance of ODS steels. [ABSTRACT FROM AUTHOR]

The non-equilibrium molecular dynamics method is adapted to calculate the phonon thermal conductivity of alphazirconium. By exchanging velocities of atoms in different regions, the stable heat flux and the temperature gradient are established to calculate the thermal conductivity. The phonon thermal conductivities under different conditions, such as different heat exchange frequencies, different temperatures, different crystallographic orientations, and crossing grain boundary (GB), are studied in detail with considering the finite size effect. It turns out that the phonon thermal conductivity decreases with the increase of temperature, and displays anisotropies along different crystallographic orientations. The phonon thermal conductivity in [0001] direction (close-packed plane) is largest, while the values in other two directions of [2......0] and [01...0] are relatively close. In the region near GB, there is a sharp temperature drop, and the phonon thermal conductivity is about one-tenth of that of the single crystal at 550 K, suggesting that the GB may act as a thermal barrier in the crystal. [ABSTRACT FROM AUTHOR]

The adsorption behaviors of radioactive strontium and silver nuclides on the graphite surface in a high-temperature gas-cooled reactor are studied by first-principles theory using generalized gradient approximation (GGA) and local density approximation (LDA) pseudo-potentials. It turns out that Sr prefers to be absorbed at the hollow of the carbon hexagonal cell by 0.54 eV (GGA), while Ag likes to sit right above the carbon atom with an adsorption energy of almost zero (GGA) and 0.45 eV (LDA). Electronic structure analysis reveals that Sr donates its partial electrons of the 4p and 5s states to the graphite substrate, while Ag on graphite is a physical adsorption without any electron transfer. [ABSTRACT FROM AUTHOR]