Karpov, S. A.Tolstolutskaya, G. D.Kalchenko, A. S.
8页
查看更多>>摘要：Ion implantation technique and nuclear reaction analysis were used to study the trapping behavior of deuterium by radiation defects in 316 austenitic stainless steel. Defect structure with a different ratio of displacement per atom (dpa) to argon gaseous impurity along with a depth has been formed by pre -irradiation of SS316 with 1.4 MeV argon ions. The deuterium migration between layers containing various defect types served as an indicator of traps strength. Computational evaluation of deuterium trapping process within the framework of the diffusion-trapping model has shown that gas-bubbles associated traps turn out to be a strongest deuterium traps with a binding energy of 0.74 eV. Other irradiation-induced defect types have a weaker effect on deuterium retention in austenitic steel. Experimental ob-servations and calculation results are discussed with respect to the possibility of molecular hydrogen formation in radiation-induced nanovoids under operating conditions of water-cooled reactor internals.(c) 2022 Published by Elsevier B.V.
查看更多>>摘要：Tungsten-tantalum (W-Ta) alloys containing 1-5%Ta were developed for fusion reactor applications. For the mechanical properties and resistance against recrystallization in the non-irradiated state, Ta-alloying improved the performance of W. Grain refining and solute Ta improved the recrystallization temperature and strength. In addition, W-1%Ta exhibited a superior ductility, including ductile-to-brittle transition temperature (DBTT), which might be attributed to the strength of sub-grain boundary. Proton irradiation study at 1500 degrees C to 0.5 dpa revealed a decrease in irradiation hardening (increase in hardness) in recrystallized specimens and a decrease in hardness reduction in as-received specimens with increasing Ta concentration. With respect to the high temperature irradiation of the as-received specimens, microstructural recovery followed by recrystallization could be one of the dominant factors affecting the hardness change. As a material performance required for the actual components of fusion reactors, resistance against high heat flux exposure have been studied through thermal shock tests. Thorough this experiment, it was clarified that the degradation by high heat flux exposure could be suppressed due to Ta-alloying.
查看更多>>摘要：This study aims to determine the effect of temperature and dissolved oxygen content on the dissolved iron concentration in liquid sodium at equilibrium. Based on the mass variation of the samples, the ap-plied experimental approach avoids the conventional but inaccurate chemical analysis that requires rep-resentative samples of liquid metal so that trace amounts of corrosion products can be measured. The results obtained show that, under isothermal conditions at 550 ? , the equilibrium iron concentration fol-lows a power law of an order very close to 2 as a function of the initial oxygen content. These results demonstrate unequivocally that the increase in the iron solubility, in the presence of dissolved oxygen, is directly related to a chemical reaction of complexation. The presence in solution of this corrosion product was hypothesized over more than 50 years ago. The stoichiometry of this soluble complex is thought to be NaFeO2. Based on this interpretation and on our experimental measurements, an equilibrium law of this complex in liquid sodium was developed as a function of temperature and dissolved oxygen content. This analytical law can be extrapolated to low dissolved oxygen contents, provided that the contribution of atomic iron to the total dissolved iron in solution is taken into account. (C) 2022 Elsevier B.V. All rights reserved.
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Elsevier