Pub Date : 2025-12-01DOI: 10.1016/j.fusengdes.2025.115542
Ireneusz Książek , Tomasz Fornal , Birger Buttenschön , Monika Kubkowska , Rainer Burhenn , Katarzyna Książek , Ralph Laube , the W7-X Team
A new diagnostic system designed for monitoring low-Z plasma impurities was constructed and successfully commissioned during the operational phase OP2 of the Wendelstein 7-X experiment [1]. The system is working based on recording the emission of the Lyman-α spectral lines emitted by hydrogen-like ions of carbon and oxygen (a second subsystem designed to measure the boron and nitrogen line is planned to be installed in the future). The first results obtained during the campaign OP2 showed that the system works following the design assumptions, and its properties comply with the numerical simulations. These findings suggest that this diagnostic system can be an important tool for scientific research of the stellarator plasmas.
{"title":"Commissioning and first results obtained by the C/O monitor system at the Wendelstein7‑X stellarator","authors":"Ireneusz Książek , Tomasz Fornal , Birger Buttenschön , Monika Kubkowska , Rainer Burhenn , Katarzyna Książek , Ralph Laube , the W7-X Team","doi":"10.1016/j.fusengdes.2025.115542","DOIUrl":"10.1016/j.fusengdes.2025.115542","url":null,"abstract":"<div><div>A new diagnostic system designed for monitoring low-Z plasma impurities was constructed and successfully commissioned during the operational phase OP2 of the Wendelstein 7-X experiment [<span><span>1</span></span>]. The system is working based on recording the emission of the Lyman-α spectral lines emitted by hydrogen-like ions of carbon and oxygen (a second subsystem designed to measure the boron and nitrogen line is planned to be installed in the future). The first results obtained during the campaign OP2 showed that the system works following the design assumptions, and its properties comply with the numerical simulations. These findings suggest that this diagnostic system can be an important tool for scientific research of the stellarator plasmas.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"223 ","pages":"Article 115542"},"PeriodicalIF":2.0,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145625421","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-29DOI: 10.1016/j.fusengdes.2025.115546
Fei Li, Wusheng Chou, Zhongyang Li
Remote maintenance inside the Tokamak vacuum vessel is constrained by extreme radiation, high temperature, and limited space, posing stringent requirements on manipulator design. This paper presents a hierarchical robust optimization framework that decomposes the design process into macro-level feasibility assurance and micro-level worst-case performance optimization. At the macro level, a feasibility heatmap method is introduced, which systematically identifies the minimum feasible configuration. Results show that a 4-DOF planar manipulator with and joint limits of 150° provides the optimal macro design. At the micro level, a Minimax robust optimization model is formulated to minimize the worst-case Jacobian condition number, and an improved Refined Pattern Search–Simulated Annealing (RPSA) algorithm is developed to solve it efficiently. Case studies demonstrate that the proposed method reduces the worst-case condition number from 9942.5 to 5021.2, with an average improvement of 28% and up to 55% at critical task points. The framework offers a systematic and generalizable pathway for early-stage manipulator design in Tokamak in-vessel maintenance, improving both feasibility assurance and robustness under extreme operating conditions.
{"title":"Hierarchical robust optimization framework for tokamak in-vessel maintenance manipulator design","authors":"Fei Li, Wusheng Chou, Zhongyang Li","doi":"10.1016/j.fusengdes.2025.115546","DOIUrl":"10.1016/j.fusengdes.2025.115546","url":null,"abstract":"<div><div>Remote maintenance inside the Tokamak vacuum vessel is constrained by extreme radiation, high temperature, and limited space, posing stringent requirements on manipulator design. This paper presents a hierarchical robust optimization framework that decomposes the design process into macro-level feasibility assurance and micro-level worst-case performance optimization. At the macro level, a feasibility heatmap method is introduced, which systematically identifies the minimum feasible configuration. Results show that a 4-DOF planar manipulator with <span><math><mrow><msub><mrow><mi>L</mi></mrow><mrow><mtext>total</mtext></mrow></msub><mo>=</mo><mtext>5645</mtext><mspace></mspace><mtext>mm</mtext></mrow></math></span> and joint limits of <span><math><mo>±</mo></math></span>150° provides the optimal macro design. At the micro level, a Minimax robust optimization model is formulated to minimize the worst-case Jacobian condition number, and an improved Refined Pattern Search–Simulated Annealing (RPSA) algorithm is developed to solve it efficiently. Case studies demonstrate that the proposed method reduces the worst-case condition number from 9942.5 to 5021.2, with an average improvement of 28% and up to 55% at critical task points. The framework offers a systematic and generalizable pathway for early-stage manipulator design in Tokamak in-vessel maintenance, improving both feasibility assurance and robustness under extreme operating conditions.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"222 ","pages":"Article 115546"},"PeriodicalIF":2.0,"publicationDate":"2025-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145684657","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Temperature measurement in plasma-surface interaction studies is an important task. Pyrometry is widely used for these purposes. This study evaluates the accuracy of a two-color pyrometer developed to investigate thermal shock effects in high-temperature ceramics – promising plasma-facing materials of fusion devices. Based on emissivity data of such ceramic materials as boron carbide (BC), silicon carbide (SiC) and zirconium diboride (ZrB), calculations showed the possibility of using this method to measure temperatures in the range of 1200–2000 K. Experimental temperature measurements during the pulsed heating of the specified ceramics showed that the deviations of single color temperatures from two-color ones were less than 5%, which demonstrates the suitability of the two-color method for measuring the surface temperatures of these materials.
{"title":"Applicability of two-color pyrometer for surface temperature measurements of ceramics, promising as plasma-facing materials","authors":"G.A. Ryzhkov , D.E. Cherepanov , M.A. Golosov , A.A. Kasatov , V.A. Popov , L.N. Vyacheslavov , N.I. Baklanova , G.G. Lazareva","doi":"10.1016/j.fusengdes.2025.115545","DOIUrl":"10.1016/j.fusengdes.2025.115545","url":null,"abstract":"<div><div>Temperature measurement in plasma-surface interaction studies is an important task. Pyrometry is widely used for these purposes. This study evaluates the accuracy of a two-color pyrometer developed to investigate thermal shock effects in high-temperature ceramics – promising plasma-facing materials of fusion devices. Based on emissivity data of such ceramic materials as boron carbide (B<span><math><msub><mrow></mrow><mrow><mn>4</mn></mrow></msub></math></span>C), silicon carbide (SiC) and zirconium diboride (ZrB<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>), calculations showed the possibility of using this method to measure temperatures in the range of 1200–2000 K. Experimental temperature measurements during the pulsed heating of the specified ceramics showed that the deviations of single color temperatures from two-color ones were less than 5%, which demonstrates the suitability of the two-color method for measuring the surface temperatures of these materials.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"222 ","pages":"Article 115545"},"PeriodicalIF":2.0,"publicationDate":"2025-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145684655","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-27DOI: 10.1016/j.fusengdes.2025.115544
Shuang Yang , Lei Li , Shangzhi Wu , Yanqing Wang , Yumin Wang , Haishan Zhou , Xiang Liu , Kaiming Feng , Minsheng Liu
ENN Science and Technology Development Co., Ltd. (ENN) has designed and constructed a specialized proton-boron linear plasma device, ENN-PSI, to investigate the irradiation-resistance performance of divertor materials. The plasma source, which employs a cascaded arc and hot cathode configuration, has successfully achieved stable proton-boron plasma discharges using diborane gas. The device was operated under a magnetic field exceeding 0.6 T and the plasma beam diameter was around 15 mm. Langmuir probe diagnostics results indicate electron temperature (Te) above 8 eV, particle flux exceeding 1 × 10²² m-²s-1, and electron density (ne) greater than 1 × 10¹⁸ m-³. These parameters meet the fundamental experimental requirements for proton-boron plasma material irradiation research, providing a robust platform for advancing the understanding of divertor material performance under proton-boron fusion conditions.
{"title":"Construction and preliminary discharge investigation of a proton-boron linear plasma device","authors":"Shuang Yang , Lei Li , Shangzhi Wu , Yanqing Wang , Yumin Wang , Haishan Zhou , Xiang Liu , Kaiming Feng , Minsheng Liu","doi":"10.1016/j.fusengdes.2025.115544","DOIUrl":"10.1016/j.fusengdes.2025.115544","url":null,"abstract":"<div><div>ENN Science and Technology Development Co., Ltd. (ENN) has designed and constructed a specialized proton-boron linear plasma device, ENN-PSI, to investigate the irradiation-resistance performance of divertor materials. The plasma source, which employs a cascaded arc and hot cathode configuration, has successfully achieved stable proton-boron plasma discharges using diborane gas. The device was operated under a magnetic field exceeding 0.6 T and the plasma beam diameter was around 15 mm. Langmuir probe diagnostics results indicate electron temperature (T<sub>e</sub>) above 8 eV, particle flux exceeding 1 × 10²² m<sup>-</sup>²s<sup>-1</sup>, and electron density (n<sub>e</sub>) greater than 1 × 10¹⁸ m<sup>-</sup>³. These parameters meet the fundamental experimental requirements for proton-boron plasma material irradiation research, providing a robust platform for advancing the understanding of divertor material performance under proton-boron fusion conditions.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"222 ","pages":"Article 115544"},"PeriodicalIF":2.0,"publicationDate":"2025-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145684656","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-27DOI: 10.1016/j.fusengdes.2025.115535
J.A. Pittard , M.Y. Lavrentiev , N.A. Fox
Diamond has several possible applications within fusion reactors, including windows, sensors/diagnostics and has shown promise as a plasma facing material. For some of these applications, polycrystalline diamond may be preferable to single crystal, meaning the impact of grain boundaries on retention mechanisms needs to be understood. As such, this work presents molecular dynamics simulations of deuterium bombardment normal to the (110) surface of four grain boundaries common to diamond grown via chemical vapour deposition. Repeated single bombardments of pristine structures showed channelling effects for some grain boundaries, that resulted in very high penetration depths. Furthermore, the additional space present in the grain boundaries allowed vacancies to form along the grain boundary at depths comparable to the deuterium depth - in contrast to bulk regions for which vacancy formation was limited to the surface. For continuous bombardment simulations, the formation of a disordered layer prevented channelling effects from playing a significant role, particularly for higher energies. A small increase in retention was observed in grain boundaries which was thought to be a result of the additional space within the grain boundary. Results presented here suggest changes in retention would be small for polycrystalline diamond of reasonable grain size.
{"title":"Simulated bombardment of diamond grain boundaries with deuterium","authors":"J.A. Pittard , M.Y. Lavrentiev , N.A. Fox","doi":"10.1016/j.fusengdes.2025.115535","DOIUrl":"10.1016/j.fusengdes.2025.115535","url":null,"abstract":"<div><div>Diamond has several possible applications within fusion reactors, including windows, sensors/diagnostics and has shown promise as a plasma facing material. For some of these applications, polycrystalline diamond may be preferable to single crystal, meaning the impact of grain boundaries on retention mechanisms needs to be understood. As such, this work presents molecular dynamics simulations of deuterium bombardment normal to the (110) surface of four grain boundaries common to diamond grown via chemical vapour deposition. Repeated single bombardments of pristine structures showed channelling effects for some grain boundaries, that resulted in very high penetration depths. Furthermore, the additional space present in the grain boundaries allowed vacancies to form along the grain boundary at depths comparable to the deuterium depth - in contrast to bulk regions for which vacancy formation was limited to the surface. For continuous bombardment simulations, the formation of a disordered layer prevented channelling effects from playing a significant role, particularly for higher energies. A small increase in retention was observed in grain boundaries which was thought to be a result of the additional space within the grain boundary. Results presented here suggest changes in retention would be small for polycrystalline diamond of reasonable grain size.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"222 ","pages":"Article 115535"},"PeriodicalIF":2.0,"publicationDate":"2025-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145684652","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-25DOI: 10.1016/j.fusengdes.2025.115540
Bin Yu , Yongtao An , Dong Wang , Guangcheng Yang , Fei Gao , Xueling Zhang , Fei Jiang , Min Chen , Xin Zhang , Zhanghong Shi , Can Tang , Ang Song , Dongwen Wang , Jiangfeng Song , Yan Shi , Changan Chen , Wei Shi , Peilong Li , Wenhua Luo
As nuclear and fusion energy technologies advance, the tritiated water management poses a critical challenge. Herein, we developed and constructed a heat-pump-integrated water distillation facility, which enables energy-efficient and high-performance treatment of tritiated water. This facility achieved a peak tritium Detritiation Factor (DF) of (2.72 ± 0.16) × 104 during continuous processing at feedwater throughputs of 10.6 L/h, reducing the tritium activity from 1.82 × 105 Bq/L to 6.7 Bq/L. An operational assessment with a maxim um processing capacity of 20.6 L/h has been carried out and DF of 315 was achieved. Furthermore, our developed structured packing DTC-APD demonstrated a height equivalent of a theoretical plate (HETP) within the range of 9.9–10.6 cm, surpassing performance levels typically reported in the literature for similar structured packings in tritiated water treatment facility. Notably, the energy consumption for processing tritiated wastewater decreased by 77.7% compared to conventional distillation techniques. Heat pump distillation was successfully applied to tritiated water treatment, maintaining stable operation for 1632 h. Therefore, this method enables economical and efficient processing of large-volume, low-concentration tritiated wastewater, which represents a significant advancement for tritiated water engineering in nuclear and fusion energy applications.
{"title":"An heat-pump-integrated water distillation facility for high-efficiency, ultralow energy consumption tritiated water treatment","authors":"Bin Yu , Yongtao An , Dong Wang , Guangcheng Yang , Fei Gao , Xueling Zhang , Fei Jiang , Min Chen , Xin Zhang , Zhanghong Shi , Can Tang , Ang Song , Dongwen Wang , Jiangfeng Song , Yan Shi , Changan Chen , Wei Shi , Peilong Li , Wenhua Luo","doi":"10.1016/j.fusengdes.2025.115540","DOIUrl":"10.1016/j.fusengdes.2025.115540","url":null,"abstract":"<div><div>As nuclear and fusion energy technologies advance, the tritiated water management poses a critical challenge. Herein, we developed and constructed a heat-pump-integrated water distillation facility, which enables energy-efficient and high-performance treatment of tritiated water. This facility achieved a peak tritium Detritiation Factor (<em>DF</em>) of (2.72 ± 0.16) × 10<sup>4</sup> during continuous processing at feedwater throughputs of 10.6 L/h, reducing the tritium activity from 1.82 × 10<sup>5</sup> Bq/L to 6.7 Bq/L. An operational assessment with a maxim um processing capacity of 20.6 L/h has been carried out and <em>DF</em> of 315 was achieved. Furthermore, our developed structured packing DTC-APD demonstrated a height equivalent of a theoretical plate (<em>HETP</em>) within the range of 9.9–10.6 cm, surpassing performance levels typically reported in the literature for similar structured packings in tritiated water treatment facility. Notably, the energy consumption for processing tritiated wastewater decreased by 77.7% compared to conventional distillation techniques. Heat pump distillation was successfully applied to tritiated water treatment, maintaining stable operation for 1632 h. Therefore, this method enables economical and efficient processing of large-volume, low-concentration tritiated wastewater, which represents a significant advancement for tritiated water engineering in nuclear and fusion energy applications.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"222 ","pages":"Article 115540"},"PeriodicalIF":2.0,"publicationDate":"2025-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145684654","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Low-energy and high-flux helium plasma irradiation can cause serious erosion and damage to the surface of tungsten (W), resulting in the formation of defects, holes and fuzz structures. The formation of these surface structures will significantly degrade the material's thermal conductivity, disrupt surface temperature distribution, and lead to surface degradation, thereby reducing the irradiation resistance of the material.To address this issue, this study introduces lanthanum oxide (La2O3) as a second phase to effectively reduce large-angle grain boundaries on the W surface and inhibit helium bubble formation by preventing helium plasma accumulation. The result shows that compared with pure tungsten (PW), W-La2O3 composite (the mass fraction of La2O3 second phase is 1 %) exhibits stronger resistance to helium plasma irradiation. Under the irradiation condition of helium plasma beam current of 2.91×1021 ions/m2·s and the dose of 3.492×1024 ions/m2, the W-La2O3 composite surface presents a wavy surface structure, which is different from the typical fuzzy surface structure formed on the pure W, indicating a significant alteration in defect evolution. With the irradiation dose increased to 13.020×1024 ions/m2, the wavy surface structure disappears, and the surface structure exhibits a classical pyramidal surface structure. The simulation results of SRIM software further reveal that the La2O3 second phase helps to transfer the helium plasma gathered on the W surface to a deeper place inside the material. In this way, the aggregation of helium ions on the surface is effectively alleviated, the formation process of the fuzz structure is delayed, and the stability of the irradiated surface structure is significantly improved. This study provides a novel design strategy for improving the anti-radiation performance of W-based plasma-facing materials in extreme fusion environments.
{"title":"The effect of La2O3 on the irradiation resistance of tungsten under low energy and high flux helium plasma irradiation","authors":"Kaichao Fu , Dang Xu , Changcheng Sang , Ruizhi Chen , Pengqi Chen , Dahuan Zhu , Qiu Xu , Jigui Cheng","doi":"10.1016/j.fusengdes.2025.115531","DOIUrl":"10.1016/j.fusengdes.2025.115531","url":null,"abstract":"<div><div>Low-energy and high-flux helium plasma irradiation can cause serious erosion and damage to the surface of tungsten (W), resulting in the formation of defects, holes and fuzz structures. The formation of these surface structures will significantly degrade the material's thermal conductivity, disrupt surface temperature distribution, and lead to surface degradation, thereby reducing the irradiation resistance of the material.To address this issue, this study introduces lanthanum oxide (La<sub>2</sub>O<sub>3</sub>) as a second phase to effectively reduce large-angle grain boundaries on the W surface and inhibit helium bubble formation by preventing helium plasma accumulation. The result shows that compared with pure tungsten (PW), W-La<sub>2</sub>O<sub>3</sub> composite (the mass fraction of La<sub>2</sub>O<sub>3</sub> second phase is 1 %) exhibits stronger resistance to helium plasma irradiation. Under the irradiation condition of helium plasma beam current of 2.91×10<sup>21</sup> ions/m<sup>2</sup>·s and the dose of 3.492×10<sup>24</sup> ions/m<sup>2</sup>, the W-La<sub>2</sub>O<sub>3</sub> composite surface presents a wavy surface structure, which is different from the typical fuzzy surface structure formed on the pure W, indicating a significant alteration in defect evolution. With the irradiation dose increased to 13.020×10<sup>24</sup> ions/m<sup>2</sup>, the wavy surface structure disappears, and the surface structure exhibits a classical pyramidal surface structure. The simulation results of SRIM software further reveal that the La<sub>2</sub>O<sub>3</sub> second phase helps to transfer the helium plasma gathered on the W surface to a deeper place inside the material. In this way, the aggregation of helium ions on the surface is effectively alleviated, the formation process of the fuzz structure is delayed, and the stability of the irradiated surface structure is significantly improved. This study provides a novel design strategy for improving the anti-radiation performance of W-based plasma-facing materials in extreme fusion environments.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"222 ","pages":"Article 115531"},"PeriodicalIF":2.0,"publicationDate":"2025-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145684651","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Reduced-activation ferritic/martensitic steel (F82H) is considered as a promising structural material for the fusion blanket structural system following the DEMO reactor. For blanket fabrication, hot isostatic pressing (HIP) is employed for the production of components with complex geometries. A key challenge associated with the HIP processing of F82H steels is the formation of silicon oxide at the HIPed interface, which results in reduced joint toughness. This study investigates the correlation between the thermodynamic stability of oxides and researches whether the silicon precipitation is the special property of silicon or not. An FeCrAl alloy containing Si was selected for comparison with F82H steel, and both materials were subjected to identical processing conditions. Silicon oxides were observed at the F82H steel-HIPed interface, whereas aluminum oxides were observed in the FeCrAl alloy. No Si precipitation or accumulation was detected at the HIP-treated interface of the FeCrAl alloy. This research showed that the silicon precipitation on F82H HIPed interface is not a special property of silicon but a general behavior of the elements along the thermodynamics and formation energy of oxides.
{"title":"Study of chemical content effects for oxide formation on HIPed interface during the fabrication process by comparison of F82H steel with FeCrAl alloy","authors":"Hirotatsu Kishimoto , Tamaki Shibayama , Takashi Nozawa , Hiroyasu Tanigawa","doi":"10.1016/j.fusengdes.2025.115541","DOIUrl":"10.1016/j.fusengdes.2025.115541","url":null,"abstract":"<div><div>Reduced-activation ferritic/martensitic steel (F82H) is considered as a promising structural material for the fusion blanket structural system following the DEMO reactor. For blanket fabrication, hot isostatic pressing (HIP) is employed for the production of components with complex geometries. A key challenge associated with the HIP processing of F82H steels is the formation of silicon oxide at the HIPed interface, which results in reduced joint toughness. This study investigates the correlation between the thermodynamic stability of oxides and researches whether the silicon precipitation is the special property of silicon or not. An FeCrAl alloy containing Si was selected for comparison with F82H steel, and both materials were subjected to identical processing conditions. Silicon oxides were observed at the F82H steel-HIPed interface, whereas aluminum oxides were observed in the FeCrAl alloy. No Si precipitation or accumulation was detected at the HIP-treated interface of the FeCrAl alloy. This research showed that the silicon precipitation on F82H HIPed interface is not a special property of silicon but a general behavior of the elements along the thermodynamics and formation energy of oxides.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"222 ","pages":"Article 115541"},"PeriodicalIF":2.0,"publicationDate":"2025-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145684653","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-24DOI: 10.1016/j.fusengdes.2025.115533
Wei Zheng , Qian Xu , Jichan Xu , Xin Yang , Haishan Zhou , Guangnan Luo
To meet the demanding requirements for high-precision, spatially-resolved diagnostics in plasma-material interaction (PMI) studies under the high-flux, high-magnetic-field environment of the SPARROW linear plasma device, an actively water-cooled Langmuir probe array system has been designed and developed. This design synergizes actively water-cooling with array layout requirements, with a focus on optimizing the cooling channel structure. Through systematic computational fluid dynamics (CFD) simulations, the thermal performance of the probe was quantitatively evaluated under Gaussian-distributed heat fluxes of 10 MW/m², 15 MW/m², and 20 MW/m², along with the impact on the probe body and the key insulating material (alumina ceramic). Under the 15 MW/m² heat flux, the maximum temperatures of the tungsten tip and alumina sleeve are maintained at approximately 62% and 61% of their respective safety limits. Even under the extreme 20 MW/m² condition, these key diagnostic components remain below 75% of their limits, demonstrating a substantial safety buffer that accommodates potential CFD uncertainties. By integrating innovative design with comprehensive thermal analysis, this research establishes key technical foundations for achieving efficient and reliable arrayed active diagnostics in extreme fusion-relevant plasma environments. It provides vital support for future high-parameter plasma physics experiments.
{"title":"Design and thermal analysis of an actively water-cooled array probe for the SPARROW device","authors":"Wei Zheng , Qian Xu , Jichan Xu , Xin Yang , Haishan Zhou , Guangnan Luo","doi":"10.1016/j.fusengdes.2025.115533","DOIUrl":"10.1016/j.fusengdes.2025.115533","url":null,"abstract":"<div><div>To meet the demanding requirements for high-precision, spatially-resolved diagnostics in plasma-material interaction (PMI) studies under the high-flux, high-magnetic-field environment of the SPARROW linear plasma device, an actively water-cooled Langmuir probe array system has been designed and developed. This design synergizes actively water-cooling with array layout requirements, with a focus on optimizing the cooling channel structure. Through systematic computational fluid dynamics (CFD) simulations, the thermal performance of the probe was quantitatively evaluated under Gaussian-distributed heat fluxes of 10 MW/m², 15 MW/m², and 20 MW/m², along with the impact on the probe body and the key insulating material (alumina ceramic). Under the 15 MW/m² heat flux, the maximum temperatures of the tungsten tip and alumina sleeve are maintained at approximately 62% and 61% of their respective safety limits. Even under the extreme 20 MW/m² condition, these key diagnostic components remain below 75% of their limits, demonstrating a substantial safety buffer that accommodates potential CFD uncertainties. By integrating innovative design with comprehensive thermal analysis, this research establishes key technical foundations for achieving efficient and reliable arrayed active diagnostics in extreme fusion-relevant plasma environments. It provides vital support for future high-parameter plasma physics experiments.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"222 ","pages":"Article 115533"},"PeriodicalIF":2.0,"publicationDate":"2025-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145684658","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-22DOI: 10.1016/j.fusengdes.2025.115530
Tamás Szepesi , A. Buzás , G. Cseh , G. Kocsis , Á. Kovácsik , D.I. Réfy , T. Szabolics , H. Homma , T. Nakano , M. Yoshida , W. Bin , G. De Tommasi , F. Fiorenza , D. Frattolillo , M. Iafrati , M. Mattei , A. Pironti , D. Ricci , C. Sozzi , J. Svoboda , J. Cavalier
EDICAM (Event Detection Intelligent Camera), a wide-angle visible overview camera diagnostic, was operated throughout the successful Integrated Commissioning and first operation campaign (IC&OP1) of JT-60SA, the world’s largest superconducting tokamak. It provided immediate and essential visual feedback after each discharge, supporting plasma operation and scenario development. In early attempts where burn-through failed and plasma current remained low, EDICAM captured plasmas appearing as two thin, radiative cylindrical surfaces—matching the resonance layers of the applied electron cyclotron heating waves. During successful discharges, the formation of magnetic surfaces was confirmed. Smaller plasmas, partially filling the torus, showed a distinct radiation belt at the low-temperature plasma edge. This belt served as a visual proxy for tracking plasma size evolution. For larger plasmas, EDICAM images were dominated by bright regions of plasma-wall interaction (PWI), especially at the limiters and the central column’s heat shield. The transition from a visible radiation belt to pronounced PWI regions indicated that the plasma had reached its maximum size. Diverted plasma formation was also identified by the presence of divertor strike-lines, which brightened as the plasma current increased. These strike-lines gradually shifted inward, consistent with the decreasing current in the central solenoid due to flux consumption. In addition, EDICAM detected unexpected PWI events, such as hot-spots, which resulted in sprays of particles entering the plasma. Altogether, EDICAM proved to be an essential diagnostic tool for the interpretation of plasma behavior during JT-60SA’s initial operational phase.
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