deuterium plasma
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Author(s):  
V. S. M. Pereira ◽  
S. Wang ◽  
T. Morgan ◽  
H. Schut ◽  
J. Sietsma

AbstractIn the present work, an ODS 12 Cr steel was characterized using Electron Microscopy techniques, in an as-received condition and after annealing treatments between 773 K and 1573 K. Results show a complex microstructure, with the presence of fine Y–Ti–O nanoparticles dispersed in the matrix. After annealing at 1573 K, the average diameter of Y–Ti–O nanoparticles increases from ~ 4 to ~ 7 nm and partial recrystallization occurs. The trapping behavior of deuterium in the steel in its as-received state and annealed at 1573 K was investigated. Samples were exposed to low-energy deuterium plasma and analyzed with thermal desorption spectroscopy, after waiting times of 1 day and 25 days. The samples measured 1 day after exposure released a higher total amount of deuterium than the ones measured after 25 days. The effect of waiting time is explained by the release of deuterium, at 300 K, from sites with low activation energy for detrapping, Ed. In the as-received condition, part of the deuterium detrapped at 300 K was re-trapped by high-Ed sites. For the samples in the annealed condition, the redistribution of deuterium from low-Ed to high-Ed sites was not observed, but the total amount of deuterium released was higher.


2021 ◽  
Author(s):  
Alina Eksaeva ◽  
Andreas Kirschner ◽  
Juri Romazanov ◽  
Sebastijan Brezinsek ◽  
Christian Linsmeier ◽  
...  

Abstract Erosion and deposition is modelled with ERO2.0 for a hypothetical full-tungsten ITER for an ELM-free H-Mode baseline deuterium discharge. A parameter study considering seeding impurities (Ne, Ar, Kr, Xe) at constant percentages (0.05% to 1.0%) of the deuterium ion flux is done while neglecting their radiation cooling and core plasma compatibility. With pure deuterium plasma, tungsten main wall erosion is only due to charge exchange deuterium atoms and self-sputtering and there is only minor tungsten divertor sputtering. With a beryllium main wall, beryllium erosion is due to deuterium ions, charge exchange deuterium neutrals and self-sputtering. For this case, tungsten in the divertor is eroded by beryllium ions and self-sputtering. The simulations for full-tungsten device including seeded impurities leads to significant tungsten erosion in the divertor. In general, tungsten erosion, self-sputtering and deposition increase by factors larger than 50 at the main wall and 5000 in the divertor compared to pure deuterium plasma


2021 ◽  
Vol 62 (1) ◽  
pp. 016004
Author(s):  
S. Kamio ◽  
K. Saito ◽  
R. Seki ◽  
H. Kasahara ◽  
M. Kanda ◽  
...  

Abstract The characteristics of ion cyclotron range of frequencies (ICRF) minority ion heating with a hydrogen minority and deuterium majority plasma were studied by ICRF modulation injection experiments in the Large Helical Device (LHD). In recent experiments with deuterium plasma, no significant increase in the neutron emission rate due to ICRF second harmonic deuteron heating was observed. Therefore, in this study, the neutron emission rate was used to refer to the information regarding the thermal ion component. Like the results of the observations of the heating efficiencies at various minority proton ratios, the experimental results showed good agreement with the simple model simulation of ICRF wave absorption. During these experiments, the accelerated minority hydrogen ions were observed by neutral particle analyzers. The counting rates of the energetic particles were higher in the lines of sight passing through the helical ripple than across the magnetic axis, and the counting rate decreased as the minority hydrogen ion ratio increased. The dependence of the minority hydrogen ion ratio on the density of the energetic ions was consistent with the experimentally observed heating efficiencies and simulations. The heating efficiency of ICRF minority ion heating could be well explained by simple model simulation in the LHD deuterium experiment.


2021 ◽  
Vol 84 (7) ◽  
pp. 1252-1258
Author(s):  
B. I. Khripunov ◽  
V. S. Koidan ◽  
A. I. Ryazanov ◽  
V. M. Gureev ◽  
S. T. Latushkin ◽  
...  

2021 ◽  
Vol 29 ◽  
pp. 101079
Author(s):  
Xuexi Zhang ◽  
Li Qiao ◽  
Hong Zhang ◽  
Weizhi Yao ◽  
Wenhao He ◽  
...  

2021 ◽  
Vol 16 (12) ◽  
pp. C12025
Author(s):  
S. Sangaroon ◽  
K. Ogawa ◽  
M. Isobe ◽  
M.I. Kobayashi ◽  
Y. Fujiwara ◽  
...  

Abstract Tangential compact neutron emission spectrometer (CNES) based on the Cs2LiYCl6:Ce with 7Li-enrichment (CLYC7) scintillator is newly installed in the Large Helical Device (LHD). Measurement of neutron energy spectrum was performed using CNES in tangential neutral beam (NB) heated deuterium plasma discharges. The Doppler shift of neutron energy according to the direction of tangential NB injection has been obtained. When the fast ions moving away from the CNES, lower shifted neutron energy is obtained, whereas the upper shifted neutron energy is obtained when the fast ions moving toward the CNES. The obtained neutron energy is almost consistent with the virgin deuterium-deuterium neutron energy evaluated by the simple two-body kinematic calculation.


2021 ◽  
Vol 173 ◽  
pp. 112862
Author(s):  
R. Yanai ◽  
T. Ii Tsujimura ◽  
S. Kubo ◽  
Y. Yoshimura ◽  
T. Takeuchi ◽  
...  

Symmetry ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 2081
Author(s):  
Boris I. Khripunov ◽  
Vasily S. Koidan ◽  
Evgeny V. Semenov

A review of experimental studies carried out at the NRC “Kurchatov Institute” on plasma-facing thermonuclear fusion reactor materials is presented in the paper. An experimental method was developed to produce high-level radiation damage in materials simulating the neutron effect by surrogate irradiation with high-energy ions. Plasma-surface interaction is investigated on materials irradiated to high levels of radiation damage in high-flux deuterium plasma. The total fluence of accelerated ions (3–30 MeV, 4He2+, 12C3+, 14N3+, protons) on the samples was 1021–1023 m−2. Experiments were carried out on graphite materials, tungsten, and silicon carbide. Samples have been obtained with a primary defect concentration from 0.1 to 100 displacements per atom, which covers the predicted damage for the ITER and DEMO projects. Erosion dynamics of the irradiated materials in steady-state deuterium plasma, changes of the surface microstructure, and deuterium retention were studied using SEM, TEM, ERDA, TDS, and nuclear backscattering techniques. The surface layer of the materials (3 to hundreds µm) was investigated, and it was shown that the changes in the crystal structure, the loss of their symmetry, and diffusion of defects to grain boundaries play an important role. The most significant results are presented in the paper as an overview of our previous work for many years (carbon and tungsten materials) as well as the relatively recent results (silicon carbide).


2021 ◽  
pp. 112936
Author(s):  
Tongjun Xia ◽  
Jing Yan ◽  
Wenjia Han ◽  
Zizhao Wang ◽  
Zhenyu Jiang ◽  
...  

2021 ◽  
pp. 101094
Author(s):  
Yi-Ming Lyu ◽  
Yu-Ping Xu ◽  
Xiao-Chun Li ◽  
Xin Shen ◽  
Bo-Yu Wu ◽  
...  

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