Nucleation of Helium in Liquid Lithium at 843 K and High Pressures
Fusion energy stands out as a promising alternative for a future decarbonised energy system. In order to be sustainable, future fusion nuclear reactors will have to produce their own tritium. In the so-called breeding blanket of a reactor, the neutron bombardment of lithium will produce the desired...
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MDPI AG
2022-04-01
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| Online Access: | https://www.mdpi.com/1996-1944/15/8/2866 |
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| author | Jordi Martí Ferran Mazzanti Grigori E. Astrakharchik Lluís Batet Laura Portos-Amill Borja Pedreño |
| author_facet | Jordi Martí Ferran Mazzanti Grigori E. Astrakharchik Lluís Batet Laura Portos-Amill Borja Pedreño |
| author_sort | Jordi Martí |
| collection | DOAJ |
| description | Fusion energy stands out as a promising alternative for a future decarbonised energy system. In order to be sustainable, future fusion nuclear reactors will have to produce their own tritium. In the so-called breeding blanket of a reactor, the neutron bombardment of lithium will produce the desired tritium, but also helium, which can trigger nucleation mechanisms owing to the very low solubility of helium in liquid metals. An understanding of the underlying microscopic processes is important for improving the efficiency, sustainability and reliability of the fusion energy conversion process. The spontaneous creation of helium droplets or bubbles in the liquid metal used as breeding material in some designs may be a serious issue for the performance of the breeding blankets. This phenomenon has yet to be fully studied and understood. This work aims to provide some insight on the behaviour of lithium and helium mixtures at experimentally corresponding operating conditions (843 K and pressures between <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mn>10</mn><mn>8</mn></msup></semantics></math></inline-formula> and 10<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mn>10</mn></msup></semantics></math></inline-formula> Pa). We report a microscopic study of the thermodynamic, structural and dynamical properties of lithium–helium mixtures, as a first step to the simulation of the environment in a nuclear fusion power plant. We introduce a new microscopic model devised to describe the formation of helium droplets in the thermodynamic range considered. Our model predicts the formation of helium droplets at pressures around 10<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mn>9</mn></msup></semantics></math></inline-formula> Pa, with radii between 1 and 2 Å. The diffusion coefficient of lithium (2 Å<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mn>2</mn></msup></semantics></math></inline-formula>/ps) is in excellent agreement with reference experimental data, whereas the diffusion coefficient of helium is in the range of 1 Å<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mn>2</mn></msup></semantics></math></inline-formula>/ps and tends to decrease as pressure increases. |
| first_indexed | 2024-03-09T04:26:31Z |
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| id | doaj.art-22cf4cd66bc24d40a8e5c978366e0e66 |
| institution | Directory Open Access Journal |
| issn | 1996-1944 |
| language | English |
| last_indexed | 2024-03-09T04:26:31Z |
| publishDate | 2022-04-01 |
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| spelling | doaj.art-22cf4cd66bc24d40a8e5c978366e0e662023-12-03T13:39:23ZengMDPI AGMaterials1996-19442022-04-01158286610.3390/ma15082866Nucleation of Helium in Liquid Lithium at 843 K and High PressuresJordi Martí0Ferran Mazzanti1Grigori E. Astrakharchik2Lluís Batet3Laura Portos-Amill4Borja Pedreño5Department of Physics, Polytechnic University of Catalonia-Barcelona Tech, 08034 Barcelona, SpainDepartment of Physics, Polytechnic University of Catalonia-Barcelona Tech, 08034 Barcelona, SpainDepartment of Physics, Polytechnic University of Catalonia-Barcelona Tech, 08034 Barcelona, SpainDepartment of Physics, Polytechnic University of Catalonia-Barcelona Tech, 08034 Barcelona, SpainBarcelona School of Telecommunications Engineering, Polytechnic University of Catalonia-Barcelona Tech, 08034 Barcelona, SpainBarcelona School of Telecommunications Engineering, Polytechnic University of Catalonia-Barcelona Tech, 08034 Barcelona, SpainFusion energy stands out as a promising alternative for a future decarbonised energy system. In order to be sustainable, future fusion nuclear reactors will have to produce their own tritium. In the so-called breeding blanket of a reactor, the neutron bombardment of lithium will produce the desired tritium, but also helium, which can trigger nucleation mechanisms owing to the very low solubility of helium in liquid metals. An understanding of the underlying microscopic processes is important for improving the efficiency, sustainability and reliability of the fusion energy conversion process. The spontaneous creation of helium droplets or bubbles in the liquid metal used as breeding material in some designs may be a serious issue for the performance of the breeding blankets. This phenomenon has yet to be fully studied and understood. This work aims to provide some insight on the behaviour of lithium and helium mixtures at experimentally corresponding operating conditions (843 K and pressures between <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mn>10</mn><mn>8</mn></msup></semantics></math></inline-formula> and 10<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mn>10</mn></msup></semantics></math></inline-formula> Pa). We report a microscopic study of the thermodynamic, structural and dynamical properties of lithium–helium mixtures, as a first step to the simulation of the environment in a nuclear fusion power plant. We introduce a new microscopic model devised to describe the formation of helium droplets in the thermodynamic range considered. Our model predicts the formation of helium droplets at pressures around 10<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mn>9</mn></msup></semantics></math></inline-formula> Pa, with radii between 1 and 2 Å. The diffusion coefficient of lithium (2 Å<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mn>2</mn></msup></semantics></math></inline-formula>/ps) is in excellent agreement with reference experimental data, whereas the diffusion coefficient of helium is in the range of 1 Å<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mn>2</mn></msup></semantics></math></inline-formula>/ps and tends to decrease as pressure increases.https://www.mdpi.com/1996-1944/15/8/2866nucleationbreeding blanketsfusion reactorshelium–lithium mixtures |
| spellingShingle | Jordi Martí Ferran Mazzanti Grigori E. Astrakharchik Lluís Batet Laura Portos-Amill Borja Pedreño Nucleation of Helium in Liquid Lithium at 843 K and High Pressures Materials nucleation breeding blankets fusion reactors helium–lithium mixtures |
| title | Nucleation of Helium in Liquid Lithium at 843 K and High Pressures |
| title_full | Nucleation of Helium in Liquid Lithium at 843 K and High Pressures |
| title_fullStr | Nucleation of Helium in Liquid Lithium at 843 K and High Pressures |
| title_full_unstemmed | Nucleation of Helium in Liquid Lithium at 843 K and High Pressures |
| title_short | Nucleation of Helium in Liquid Lithium at 843 K and High Pressures |
| title_sort | nucleation of helium in liquid lithium at 843 k and high pressures |
| topic | nucleation breeding blankets fusion reactors helium–lithium mixtures |
| url | https://www.mdpi.com/1996-1944/15/8/2866 |
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