Tritium absorption and desorption in ITER relevant materials: comparative study of tungsten dust and massive samples

Synthesis of tungsten nanopowders: Comparison of milling, SHS, MASHS and milling-induced chemical processes

“…Therefore, the 10 min pre-milling seems to have the best synthesis conditions, even better than milling-induced chemical reaction, the lowest O fraction being under 10% which represents a fraction of oxidized W atoms (WO 2 and WO 3 ) lower than 5%. Further reduction of these oxides has been proved to be possible without altering the nanostructure of the powders, using an hydrogen atmosphere at 475°C [1,2]. However, an indisputable explanation of why the optimum oxygen content is observed with a 10 min milling pretreatment is difficult to do.…”

“…In previous papers we started to study the behavior of different kinds of tungsten particles towards 3 H [1,2], and in presence of hydrogen plasma [3]. The present paper aims at providing more insights on their preparation.…”

“…Unfortunately, the availability of tokamak-retrieved powders is quite low. Therefore, in order to conduct the different studies to assess the potential dangerousness of tungsten nanopowders, including their behavior when in presence of tritium, or when facing a hydrogen plasma [1][2][3], or their cytotoxicity or their genotoxicity (study currently under progress), other means of production must be sought for. Moreover, as ITER will be a significantly larger tokamak than the presently existing ones, different morphologies might occur during its operation, and thus it would be preferable to obtain a set of different morphologies to make sure the worst case scenario can be handled.…”

Tungsten particles fabrication by a microjet discharge

“…An interesting material is Tungsten, known as a transition metal with outstanding physical and chemical properties, a high melting point, around 3400°C, having electrochemical properties [19], and a low sputtering rate. Tungsten and tungsten oxides are involved in large-scale applications in fusion technology, where we can note the importance of W material in the divertor region of ITER (International Thermonuclear Experimental Reactor) facility [20][21][22]. In addition, -one can find this attractive material used in defense applications, such as small caliber ammunition, armor plating, and high kinetic energy penetrators [1,23].…”

“…Tungsten oxide is present also in photochemical aerosol generators [28,29]. With respect to fusion technology, due to plasma-wall interactions, tungsten particles are produced, having various shapes and sizes, and presenting a potential danger for humans and environment [21]; thus, details on particles formation at plasma contact with tungsten materials, and their properties are of wide interest.…”