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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-22 2:02 |
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Conference: Bucharest University Faculty of Physics 2021 Meeting
Section: Polymer Physics
Title:
Microwave (2.45 GHz) Plasma treatments of Tungsten particles as a source for Tritium retention studies
Authors:
Valentina MARASCU(1, 2), Mickael PAYET(1,3), Sebastien GARCIA-ARGOTE(1), Sophie FEUILLASTRE(1), Gregory PIETERS(1), Vincent MERTENS(4), Frederique MISERQUE(5), Etienne Augustin HODILLE(3), Elodie BERNARD(3), Christian GRISOLIA(3)
Affiliation:
1) Université Paris-Saclay, CEA, INRAE, DMTS, SCBM, F-91191 Gif-sur-Yvette, France
2) National Institute for Laser, Plasma and Radiation Physics, RO-077125 Magurele, Romania
3) CEA, IRFM, F-13108 St Paul Lez Durance, France
4) CEA Saclay, DRF/ IRAMIS/ NIMBE/ LEDNA, F-91191 Gif-sur-Yvette, France
5) CEA Saclay, DES/ ISAS/DPC/SCCME/LECA, F-91191 Gif-sur-Yvette, France.
E-mail
valentina.marascu@gmail.com
Keywords:
W particles; materials; microwaves; hydrogen plasma, tritium gas
Abstract:
Microwave plasmas techniques represents an important domain due to their large applications, and capacity to synthesize or treat new materials, without producing major contaminations. Thus, depending on the material’s nature, microwaves can start to heat the material in all its volume (materials containing carbon, e.g., polymers), or can heat only the material surface (e.g., metallic materials). In our approach, we have used a 2.45 GHz microwave (MW) plasma discharge to treat tungsten (W) particles, in order to study Tritium retention inside particles. Hydrogen was used as a main gas for the plasma discharge. The experiments have consisted of using two steps: in the first part, 40 mg of submicronic W particles (and having various shapes) were exposed to MW Hydrogen plasma, for 44 minutes, at 100W input power, and by using a static H2 pressure = 7 mbar. After plasma treatment, W particles were transferred in a secured Gloves Box, where were exposed to 100 mbar tritium gas, under heating conditions. Morphological investigations were made for W particles before, and after plasma treatments. Indeed, by analyzing SEM images it can be observed melted particles, and the occurrence of tube-like morphologies along with nanometric particles on top of the initial W particles. From XPS analyses we have observed the oxide reduction from W particles after plasma treatment. Tritium retention in W particles was analyzed via room temperature desorption and dissolutions methods. By using room temperature method, it was showed that plasma pre-treatment facilitated the retention of tritium in W particles in a higher quantity, compared with W particles which were treated only in Hydrogen gas atmosphere under heating conditions. Tritiated particles dissolutions were made by using Hydrogen Peroxide and Sodium Hydroxide. Our results have showed that hydrogen plasma pre-treatment has produced additional nanometric particles, increasing the specific surface area (SSA) of the initial W particles. This aspect conducted further on to a higher tritium retention in W particles. Further plasma treatments conditions will be made in order to observe the threshold of the additional nanometric particles, which are responsible of a higher tritium retention.
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