Surface damages of ITER-like W/Cu monoblocks in the lower divertor of EAST
In future ITER operations, it is crucial to maintain the performance of plasma-facing components, particularly in regions subject to high thermal loads. Studies on component damage in existing tokamaks provide important reference data for predicting potential damage in ITER and future fusion devices...
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| Format: | Article |
| Language: | English |
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IOP Publishing
2025-01-01
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| Series: | Nuclear Fusion |
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| Online Access: | https://doi.org/10.1088/1741-4326/adf3c7 |
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| author | Yang Wang Dahuan Zhu Chuanshi Feng Zongxiao Guo Pengfei Zi Changjun Li Chuannan Xuan Chunyu He Wenxue Fu Binfu Gao Baoguo Wang Rui Ding Junling Chen the EAST Team |
| author_facet | Yang Wang Dahuan Zhu Chuanshi Feng Zongxiao Guo Pengfei Zi Changjun Li Chuannan Xuan Chunyu He Wenxue Fu Binfu Gao Baoguo Wang Rui Ding Junling Chen the EAST Team |
| author_sort | Yang Wang |
| collection | DOAJ |
| description | In future ITER operations, it is crucial to maintain the performance of plasma-facing components, particularly in regions subject to high thermal loads. Studies on component damage in existing tokamaks provide important reference data for predicting potential damage in ITER and future fusion devices, ensuring the most effective response strategies during future operations. In 2021, ITER-like W/Cu monoblocks featuring a large chamfer (1.5 mm × 17 mm) were installed on the lower divertor target of EAST. The structural design of W/Cu monoblocks with inclination angles can reduce the probability of melting but may also induce other types of damage, similar to the fish-scale surface of the divertor in ITER (toroidal bevel with a depth of 0.5 mm). After three plasma campaigns, post-mortem analysis identified significant surface damages, including crust formation, increased surface roughness, macrocracks, and other types of damage. The spatial distribution of damage is strongly correlated with the heat flux distribution and the degree of misalignment. At the leading edge areas, macrocracks are caused by plastic strain under steady-state heat loads, while microcracks are brittle cracks mainly caused by transient heat loads. The net-like cracks displayed four distinct morphological characteristics, attributed to variations in heat load and incident angles. Abnormal grain growth was observed in the vicinity of the melted components, with grain sizes reaching an extraordinary 7.1 mm. Both the formation and propagation of cracks were related to material degradation, such as the reduction of mechanical strength, the decrease in fracture toughness, and increased embrittlement. Molten tungsten (W) and low-Z carbon impurities can react to form tungsten carbide (W _2 C) at extremely high temperatures. Such damages on W/Cu monoblocks for the lower divertor in EAST provide critical insights into the service performance of these ITER-like W/Cu monoblocks, which can provide important reference data for the future use in ITER and other fusion reactor devices. |
| format | Article |
| id | doaj-art-4d2213e020ad4e07846b94e0125d198d |
| institution | Kabale University |
| issn | 0029-5515 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | Nuclear Fusion |
| spelling | doaj-art-4d2213e020ad4e07846b94e0125d198d2025-08-20T04:02:31ZengIOP PublishingNuclear Fusion0029-55152025-01-0165909601410.1088/1741-4326/adf3c7Surface damages of ITER-like W/Cu monoblocks in the lower divertor of EASTYang Wang0Dahuan Zhu1Chuanshi Feng2Zongxiao Guo3Pengfei Zi4Changjun Li5Chuannan Xuan6Chunyu He7https://orcid.org/0000-0002-6211-6506Wenxue Fu8Binfu Gao9https://orcid.org/0000-0003-3477-5229Baoguo Wang10Rui Ding11https://orcid.org/0000-0003-2880-9736Junling Chen12the EAST TeamInstitute of Plasma Physics , Hefei Institutes of Physical Science Chinese Academy of Sciences, Hefei 230031, China; University of Science and Technology of China , Hefei 230026, ChinaInstitute of Plasma Physics , Hefei Institutes of Physical Science Chinese Academy of Sciences, Hefei 230031, ChinaSongshan Lake Materials Laboratory , Dongguan 523808, ChinaCollege of Physics and Optoelectronics Engineering, Shenzhen University , Shenzhen 518060, ChinaInstitute of Plasma Physics , Hefei Institutes of Physical Science Chinese Academy of Sciences, Hefei 230031, ChinaInstitute of Plasma Physics , Hefei Institutes of Physical Science Chinese Academy of Sciences, Hefei 230031, ChinaInstitute of Plasma Physics , Hefei Institutes of Physical Science Chinese Academy of Sciences, Hefei 230031, China; University of Science and Technology of China , Hefei 230026, ChinaInstitute of Plasma Physics , Hefei Institutes of Physical Science Chinese Academy of Sciences, Hefei 230031, China; University of Science and Technology of China , Hefei 230026, ChinaInstitute of Plasma Physics , Hefei Institutes of Physical Science Chinese Academy of Sciences, Hefei 230031, China; University of Science and Technology of China , Hefei 230026, ChinaInstitute of Plasma Physics , Hefei Institutes of Physical Science Chinese Academy of Sciences, Hefei 230031, ChinaInstitute of Plasma Physics , Hefei Institutes of Physical Science Chinese Academy of Sciences, Hefei 230031, ChinaInstitute of Plasma Physics , Hefei Institutes of Physical Science Chinese Academy of Sciences, Hefei 230031, ChinaInstitute of Plasma Physics , Hefei Institutes of Physical Science Chinese Academy of Sciences, Hefei 230031, ChinaIn future ITER operations, it is crucial to maintain the performance of plasma-facing components, particularly in regions subject to high thermal loads. Studies on component damage in existing tokamaks provide important reference data for predicting potential damage in ITER and future fusion devices, ensuring the most effective response strategies during future operations. In 2021, ITER-like W/Cu monoblocks featuring a large chamfer (1.5 mm × 17 mm) were installed on the lower divertor target of EAST. The structural design of W/Cu monoblocks with inclination angles can reduce the probability of melting but may also induce other types of damage, similar to the fish-scale surface of the divertor in ITER (toroidal bevel with a depth of 0.5 mm). After three plasma campaigns, post-mortem analysis identified significant surface damages, including crust formation, increased surface roughness, macrocracks, and other types of damage. The spatial distribution of damage is strongly correlated with the heat flux distribution and the degree of misalignment. At the leading edge areas, macrocracks are caused by plastic strain under steady-state heat loads, while microcracks are brittle cracks mainly caused by transient heat loads. The net-like cracks displayed four distinct morphological characteristics, attributed to variations in heat load and incident angles. Abnormal grain growth was observed in the vicinity of the melted components, with grain sizes reaching an extraordinary 7.1 mm. Both the formation and propagation of cracks were related to material degradation, such as the reduction of mechanical strength, the decrease in fracture toughness, and increased embrittlement. Molten tungsten (W) and low-Z carbon impurities can react to form tungsten carbide (W _2 C) at extremely high temperatures. Such damages on W/Cu monoblocks for the lower divertor in EAST provide critical insights into the service performance of these ITER-like W/Cu monoblocks, which can provide important reference data for the future use in ITER and other fusion reactor devices.https://doi.org/10.1088/1741-4326/adf3c7EASTW/Cu monoblocksmeltingcracksrecrystallization |
| spellingShingle | Yang Wang Dahuan Zhu Chuanshi Feng Zongxiao Guo Pengfei Zi Changjun Li Chuannan Xuan Chunyu He Wenxue Fu Binfu Gao Baoguo Wang Rui Ding Junling Chen the EAST Team Surface damages of ITER-like W/Cu monoblocks in the lower divertor of EAST Nuclear Fusion EAST W/Cu monoblocks melting cracks recrystallization |
| title | Surface damages of ITER-like W/Cu monoblocks in the lower divertor of EAST |
| title_full | Surface damages of ITER-like W/Cu monoblocks in the lower divertor of EAST |
| title_fullStr | Surface damages of ITER-like W/Cu monoblocks in the lower divertor of EAST |
| title_full_unstemmed | Surface damages of ITER-like W/Cu monoblocks in the lower divertor of EAST |
| title_short | Surface damages of ITER-like W/Cu monoblocks in the lower divertor of EAST |
| title_sort | surface damages of iter like w cu monoblocks in the lower divertor of east |
| topic | EAST W/Cu monoblocks melting cracks recrystallization |
| url | https://doi.org/10.1088/1741-4326/adf3c7 |
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