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- Murari, A., et al.
(författare)
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A control oriented strategy of disruption prediction to avoid the configuration collapse of tokamak reactors
- 2024
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Ingår i: Nature Communications. - 2041-1723 .- 2041-1723. ; 15:1
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Tidskriftsartikel (refereegranskat)abstract
- The objective of thermonuclear fusion consists of producing electricity from the coalescence of light nuclei in high temperature plasmas. The most promising route to fusion envisages the confinement of such plasmas with magnetic fields, whose most studied configuration is the tokamak. Disruptions are catastrophic collapses affecting all tokamak devices and one of the main potential showstoppers on the route to a commercial reactor. In this work we report how, deploying innovative analysis methods on thousands of JET experiments covering the isotopic compositions from hydrogen to full tritium and including the major D-T campaign, the nature of the various forms of collapse is investigated in all phases of the discharges. An original approach to proximity detection has been developed, which allows determining both the probability of and the time interval remaining before an incoming disruption, with adaptive, from scratch, real time compatible techniques. The results indicate that physics based prediction and control tools can be developed, to deploy realistic strategies of disruption avoidance and prevention, meeting the requirements of the next generation of devices.
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| 6. |
- Rieth, M., et al.
(författare)
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A brief summary of the progress on the EFDA tungsten materials program
- 2013
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Ingår i: Journal of Nuclear Materials. - : Elsevier BV. - 0022-3115 .- 1873-4820. ; 442:1-3, s. S173-S180
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Tidskriftsartikel (refereegranskat)abstract
- The long-term objective of the European Fusion Development Agreement (EFDA) fusion materials programme is to develop structural and armor materials in combination with the necessary production and fabrication technologies for reactor concepts beyond the International Thermonuclear Experimental Reactor. The programmatic roadmap is structured into four engineering research lines which comprise fabrication process development, structural material development, armor material optimization, and irradiation performance testing, which are complemented by a fundamental research programme on "Materials Science and Modeling." This paper presents the current research status of the EFDA experimental and testing investigations, and gives a detailed overview of the latest results on materials research, fabrication, joining, high heat flux testing, plasticity studies, modeling, and validation experiments.
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| 7. |
- Rieth, M., et al.
(författare)
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Recent progress in research on tungsten materials for nuclear fusion applications in Europe
- 2013
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Ingår i: Journal of Nuclear Materials. - : Elsevier BV. - 0022-3115 .- 1873-4820. ; 432:1-3, s. 482-500
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Forskningsöversikt (refereegranskat)abstract
- The current magnetic confinement nuclear fusion power reactor concepts going beyond ITER are based on assumptions about the availability of materials with extreme mechanical, heat, and neutron load capacity. In Europe, the development of such structural and armour materials together with the necessary production, machining, and fabrication technologies is pursued within the EFDA long-term fusion materials programme. This paper reviews the progress of work within the programme in the area of tungsten and tungsten alloys. Results, conclusions, and future projections are summarized for each of the programme's main subtopics, which are: (1) fabrication, (2) structural W materials, (3) W armour materials, and (4) materials science and modelling. It gives a detailed overview of the latest results on materials research, fabrication processes, joining options, high heat flux testing, plasticity studies, modelling, and validation experiments.
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| 8. |
- Rieth, M., et al.
(författare)
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Review on the EFDA programme on tungsten materials technology and science
- 2011
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Ingår i: Journal of Nuclear Materials. - : Elsevier BV. - 0022-3115 .- 1873-4820. ; 417:1-3, s. 463-467
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Tidskriftsartikel (refereegranskat)abstract
- All the recent DEMO design studies for helium cooled divertors utilize tungsten materials and alloys, mainly due to their high temperature strength, good thermal conductivity, low erosion, and comparably low activation under neutron irradiation. The long-term objective of the EFDA fusion materials programme is to develop structural as well as armor materials in combination with the necessary production and fabrication technologies for future divertor concepts. The programmatic roadmap is structured into four engineering research lines which comprise fabrication process development, structural material development, armor material optimization, and irradiation performance testing, which are complemented by a fundamental research programme on "Materials Science and Modeling". This paper presents the current research status of the EFDA experimental and testing investigations, and gives a detailed overview of the latest results on fabrication, joining, high heat flux testing, plasticity, modeling, and validation experiments.
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| 9. |
- Krawczynska, A. T., et al.
(författare)
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Impact of high pressure torsion processing on helium ion irradiation resistance of molybdenum
- 2022
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Ingår i: Materials Characterization. - : Elsevier BV. - 1044-5803 .- 1873-4189. ; 191, s. 112151-
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Tidskriftsartikel (refereegranskat)abstract
- The microstructure of Mo was significantly refined by high pressure torsion to verify its irradiation tolerance in comparison with its micrograined counterpart. After deformation microhardness increased from 231 Hv0.2 for a microgarined sample to 542 and 558 Hv0.2, respectively after one and five rotations. Concurrently, the grain refinement was observed, as the grain size decreased with the increase of the deformation degree down to 480 and 110 nm, respectively for one and five rotations. Subsequently, deformed Mo and a micrograined one were irradiated by He ions to the dose of 8 x 1016/cm 2 to verify their potential application as fusion mirrors. Irra-diations were followed by reflectivity measurements in the 300-2400 nm range with a dual beam spectrometer. The measurements revealed that the applied dose causes a decrease in total reflectivity of the micrograined sample, whereas the total reflectivity of deformed samples decreases by additional 2.5%. Nanohardness mea-surements, detailed microscopy observations using focused ion beam and scanning transmission electron mi-croscope as well as positron annihilation spectroscopy investigations were performed to elucidate changes in the microstructure and understand the different mechanisms of bubble creation after irradiation in micrograined and high pressure torsion processed samples.
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