Cold Sprayed Tungsten Armor for Tokamak First Wall

Jan Kondas,Monika Vilemova,Jan Cizek,Reeti Singh,Martin Koller,Frantisek Lukac

doi:10.3390/coatings9120836

Jan Kondas, Monika Vilemova + Show 4 more

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https://doi.org/10.3390/coatings9120836

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Abstract

Harnessing nuclear fusion is a challenging task, in particular because of the demands put on the used materials. In tokamaks, future energy sources, the inner-most chambers are to be coated with dense coatings of W, or W-Cr-based alloys. So far, the attempts for such coatings formation by other methods failed due to oxidation, high porosity, insufficient adhesion, high specific surface, or even insufficient thickness below 10 μ m. Cold spraying seems a promising technology for the task. In our study, we demonstrate the first successful fabrication of thick pure W coatings. W-Cr and W-Cr-Ti coatings were further prepared without oxidation of the metals. All coatings exhibited high hardness levels, good interface quality with three tested substrates and, importantly, a promising potential for formation of stable Cr 2 WO x phases.

Highlights

Nuclear fusion is a process in which two or more light atomic nuclei combine to form a different, heavier nucleus and subatomic particles, neutrons or protons
The reaction that is currently considered the most promising for future power production is fusion of two hydrogen isotopes, deuterium (D) and tritium (T): D + T −−→ 42He + 10n. Combining these leads to formation of helium atoms carrying 3.5 MeV energy used to further heat the fuel, and free neutrons having energies of 14.1 MeV. This energy is used for breeding of tritium as well as the energy production
The microstructure of the fabricated cold sprayed coatings can be seen from Figure 4

Summary

Introduction

Nuclear fusion is a process in which two or more light atomic nuclei combine to form a different, heavier nucleus and subatomic particles, neutrons or protons. Combining these leads to formation of helium atoms carrying 3.5 MeV energy used to further heat the fuel, and free neutrons having energies of 14.1 MeV. This energy is used for breeding of tritium as well as the energy production. In order to achieve positive energy balance, it is necessary to ensure a sufficient frequency of these reactions (collisions of D and T) This translates into the requirement to keep the fuel at sufficiently high temperatures and concentrations for sufficiently long times [1,2,3]

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