Pub Date : 2026-03-01Epub Date: 2025-12-11DOI: 10.1016/j.fusengdes.2025.115577
R. Castro , Y. Makushok , L. Abadie , J. Vega
ITER, one of the most advanced fusion projects, requires handling massive amounts of data generated in real time and stored in distributed repositories. The diversity in the nature of the data, from control variables to fast acquisition signals, poses significant challenges for efficient access and organization of the information. This paper presents a large-scale indexing system designed to meet these needs. The system, integrated into ITER's CODAC core, implements a distributed and scalable architecture that ensures real-time indexing, robustness, and fault tolerance. Its design, implementation and performance are described here, highlighting its capacity to handle more than one petabyte of data per day and respond in real time to user and system requests. This breakthrough contributes significantly to efficient data handling in long-lived fusion environments.
{"title":"Large-scale indexing system for ITER data handling","authors":"R. Castro , Y. Makushok , L. Abadie , J. Vega","doi":"10.1016/j.fusengdes.2025.115577","DOIUrl":"10.1016/j.fusengdes.2025.115577","url":null,"abstract":"<div><div>ITER, one of the most advanced fusion projects, requires handling massive amounts of data generated in real time and stored in distributed repositories. The diversity in the nature of the data, from control variables to fast acquisition signals, poses significant challenges for efficient access and organization of the information. This paper presents a large-scale indexing system designed to meet these needs. The system, integrated into ITER's CODAC core, implements a distributed and scalable architecture that ensures real-time indexing, robustness, and fault tolerance. Its design, implementation and performance are described here, highlighting its capacity to handle more than one petabyte of data per day and respond in real time to user and system requests. This breakthrough contributes significantly to efficient data handling in long-lived fusion environments.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"224 ","pages":"Article 115577"},"PeriodicalIF":2.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145718900","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 : 2026-03-01Epub Date: 2025-12-13DOI: 10.1016/j.fusengdes.2025.115591
C.S. Ding , X.F. Xie , X.Y. Li , Y.J. Fu , H. Wang , R. Liu , X.B. Wu , X.P. Wang , Z.M. Xie
In this work, single-crystal W and W-ZrC alloys were irradiated with 500 keV helium (He) ions at both RT and 400 °C. Microstructural characterization revealed that both He bubble and dislocation loop densities within the grains of single-crystal W were higher than those in the W-ZrC alloy. The reduction in defect density in grains of W-ZrC is attributed to the presence of grain boundaries (GBs) and phase boundaries (PBs), which serve as effective sinks and provide preferential nucleation sites for irradiation-induced defects. Notably, PBs exhibited higher sink strength than GBs, resulting in the formation of He bubbles with greater size and density at PBs. Nanoindentation tests showed that single-crystal W exhibited more pronounced irradiation-induced hardening, with hardness increments of 2.8 GPa at room temperature (RT) and 2.3 GPa at 400 °C, which are higher than those of the W-ZrC alloy, demonstrating the enhanced irradiation tolerance of W-ZrC. The dispersed barrier hardening (DBH) model was employed to quantify the respective contributions of He bubbles and dislocation loops to hardening. The results indicated that He bubbles contributed approximately twice the hardening increment of dislocation loops in both materials. These findings clarify the critical role of interfaces in mediating defect evolution and irradiation responses, providing guidance for the design of W-based materials with improved irradiation tolerance for fusion applications.
{"title":"Distribution of He bubbles and dislocation loops in single-crystal W and W-ZrC materials after He2+ ion irradiation","authors":"C.S. Ding , X.F. Xie , X.Y. Li , Y.J. Fu , H. Wang , R. Liu , X.B. Wu , X.P. Wang , Z.M. Xie","doi":"10.1016/j.fusengdes.2025.115591","DOIUrl":"10.1016/j.fusengdes.2025.115591","url":null,"abstract":"<div><div>In this work, single-crystal W and W-ZrC alloys were irradiated with 500 keV helium (He) ions at both RT and 400 °C. Microstructural characterization revealed that both He bubble and dislocation loop densities within the grains of single-crystal W were higher than those in the W-ZrC alloy. The reduction in defect density in grains of W-ZrC is attributed to the presence of grain boundaries (GBs) and phase boundaries (PBs), which serve as effective sinks and provide preferential nucleation sites for irradiation-induced defects. Notably, PBs exhibited higher sink strength than GBs, resulting in the formation of He bubbles with greater size and density at PBs. Nanoindentation tests showed that single-crystal W exhibited more pronounced irradiation-induced hardening, with hardness increments of 2.8 GPa at room temperature (RT) and 2.3 GPa at 400 °C, which are higher than those of the W-ZrC alloy, demonstrating the enhanced irradiation tolerance of W-ZrC. The dispersed barrier hardening (DBH) model was employed to quantify the respective contributions of He bubbles and dislocation loops to hardening. The results indicated that He bubbles contributed approximately twice the hardening increment of dislocation loops in both materials. These findings clarify the critical role of interfaces in mediating defect evolution and irradiation responses, providing guidance for the design of W-based materials with improved irradiation tolerance for fusion applications.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"224 ","pages":"Article 115591"},"PeriodicalIF":2.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145747608","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 : 2026-03-01Epub Date: 2026-01-03DOI: 10.1016/j.fusengdes.2025.115611
Jinpeng Zhang , Lihua Guo , Guoqiang Wang , Jun Lin , Linyuan Lu , Jinwei Zhan
The effect of sintering temperature on the microstructural evolution and densification behaviors of W14Re2 (with a Re atomic ratio of 12.50 % and a mass ratio of 12.64 %) was explored for the first time utilizing spark plasma sintering (SPS) technology. The results reveal that Re is uniformly dispersed within the W matrix following high-energy ball milling. 1300 °C serves as a critical threshold for the microstructural transformation of W14Re2 alloy, during which the grain morphology evolves from nearly spherical to equiaxed. 1400 °C marks a pivotal temperature point for the densification transition of W14Re2, where the sample surface transforms from being porous and loose to highly dense. Overall, as the temperature rises, the grain size demonstrates a gradual increasing tendency. Specifically, the average W grain size attains approximately 1 μm at 1700 °C, which corresponds to a theoretical density of 97.47 %. Furthermore, the two phases exhibit an alternating peak-and-valley elemental concentration profile along the interface. The HRTEM reveals uniformly distributed diffraction spots with alternating intensities at the two-phase interface. These spots oscillate asymmetrically around the original lattice positions, suggesting a twin-like structural feature. This phenomenon can be attributed to Re doping-induced lattice distortion in the W matrix at elevated temperatures, coupled with interfacial interactions that facilitate solid solution formation between the phases. This study offers a preliminary investigation into the sintering properties of the W14Re2 alloy and is anticipated to establish a groundwork for facilitating further optimized preparation of W-Re alloys.
{"title":"Microstructural evolution and densification behaviors of W14Re2 alloy produced at different temperature by spark plasma sintering","authors":"Jinpeng Zhang , Lihua Guo , Guoqiang Wang , Jun Lin , Linyuan Lu , Jinwei Zhan","doi":"10.1016/j.fusengdes.2025.115611","DOIUrl":"10.1016/j.fusengdes.2025.115611","url":null,"abstract":"<div><div>The effect of sintering temperature on the microstructural evolution and densification behaviors of W<sub>14</sub>Re<sub>2</sub> (with a Re atomic ratio of 12.50 % and a mass ratio of 12.64 %) was explored for the first time utilizing spark plasma sintering (SPS) technology. The results reveal that Re is uniformly dispersed within the W matrix following high-energy ball milling. 1300 °C serves as a critical threshold for the microstructural transformation of W<sub>14</sub>Re<sub>2</sub> alloy, during which the grain morphology evolves from nearly spherical to equiaxed. 1400 °C marks a pivotal temperature point for the densification transition of W<sub>14</sub>Re<sub>2</sub>, where the sample surface transforms from being porous and loose to highly dense. Overall, as the temperature rises, the grain size demonstrates a gradual increasing tendency. Specifically, the average W grain size attains approximately 1 μm at 1700 °C, which corresponds to a theoretical density of 97.47 %. Furthermore, the two phases exhibit an alternating peak-and-valley elemental concentration profile along the interface. The HRTEM reveals uniformly distributed diffraction spots with alternating intensities at the two-phase interface. These spots oscillate asymmetrically around the original lattice positions, suggesting a twin-like structural feature. This phenomenon can be attributed to Re doping-induced lattice distortion in the W matrix at elevated temperatures, coupled with interfacial interactions that facilitate solid solution formation between the phases. This study offers a preliminary investigation into the sintering properties of the W<sub>14</sub>Re<sub>2</sub> alloy and is anticipated to establish a groundwork for facilitating further optimized preparation of W-Re alloys.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"224 ","pages":"Article 115611"},"PeriodicalIF":2.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145884846","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 : 2026-03-01Epub Date: 2025-12-13DOI: 10.1016/j.fusengdes.2025.115587
Kecheng Jiang , Lei Chen , Qiuran Wu , Yang Xiao , Songsen Wang , Songlin Liu
In this paper, we present a solid-type PbxLiy blanket and related R&D activities. This blanket concept is designed to enhance the Technical Readiness Level (TRL) by addressing risks identified in both current solid and liquid blanket designs. It employs PbxLiy with a high melting point as both neutron multiplier and tritium breeder, configured in the form of pebble beds within the solid blanket. This approach leverages mature tritium extraction technologies already developed for solid blankets, while eliminating the need for expensive beryllium. At this stage, a conceptual design of the blanket has been developed to verify its compliance with neutronics and thermal-hydraulics performance requirements. Additionally, initial fabrication of this material has been attempted, and preliminary characterizations, including density, chemical reactivity with water, and composition, have been conducted. The results confirm that the dominate composition is the PbxLiy alloy with high melting point. i.e. Li4Pb, Li3Pb, Li5Pb2 and Li10Pb3. However, there is still some purely lithium and PbxLiy at lower melting point 481.9 °C. Therefore, we need to improve the manufacturing methods to make it much more purely with high melting point, e.g. Pb28Li72 at 650 °C. In the following, we will find new way to make the element Pb/Li mixing much more uniformly, and cool them instantly during the mixing to make the solid-type PbxLiy more purely.
{"title":"Progress on the design and related R&D activities for the novel solid-type PbxLiy breeding blanket for CFETR","authors":"Kecheng Jiang , Lei Chen , Qiuran Wu , Yang Xiao , Songsen Wang , Songlin Liu","doi":"10.1016/j.fusengdes.2025.115587","DOIUrl":"10.1016/j.fusengdes.2025.115587","url":null,"abstract":"<div><div>In this paper, we present a solid-type Pb<sub>x</sub>Li<sub>y</sub> blanket and related R&D activities. This blanket concept is designed to enhance the Technical Readiness Level (TRL) by addressing risks identified in both current solid and liquid blanket designs. It employs Pb<sub>x</sub>Li<sub>y</sub> with a high melting point as both neutron multiplier and tritium breeder, configured in the form of pebble beds within the solid blanket. This approach leverages mature tritium extraction technologies already developed for solid blankets, while eliminating the need for expensive beryllium. At this stage, a conceptual design of the blanket has been developed to verify its compliance with neutronics and thermal-hydraulics performance requirements. Additionally, initial fabrication of this material has been attempted, and preliminary characterizations, including density, chemical reactivity with water, and composition, have been conducted. The results confirm that the dominate composition is the Pb<sub>x</sub>Li<sub>y</sub> alloy with high melting point. i.e. Li<sub>4</sub>Pb, Li<sub>3</sub>Pb, Li<sub>5</sub>Pb<sub>2</sub> and Li<sub>10</sub>Pb<sub>3</sub>. However, there is still some purely lithium and Pb<sub>x</sub>Li<sub>y</sub> at lower melting point 481.9 °C. Therefore, we need to improve the manufacturing methods to make it much more purely with high melting point, e.g. Pb<sub>28</sub>Li<sub>72</sub> at 650 °C. In the following, we will find new way to make the element Pb/Li mixing much more uniformly, and cool them instantly during the mixing to make the solid-type Pb<sub>x</sub>Li<sub>y</sub> more purely.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"224 ","pages":"Article 115587"},"PeriodicalIF":2.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145798993","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 : 2026-03-01Epub Date: 2025-12-16DOI: 10.1016/j.fusengdes.2025.115596
Paulo Aguayo , Gonzalo Farias , Alejandro González-Ganzábal , Ernesto Fabregas , Teresa Estrada , Boudewijn van Milligen , Alfonso Baciero , Belén López-Miranda , Francisco Medina , Giuseppe A. Rattá Gutiérrez
Magnetically confined fusion devices, such as the stellarator TJ-II, are highly complex infrastructures where plasma evolution is monitored through advanced diagnostic systems. Failures in these diagnostics can result in missing or unreliable data, compromising operational stability and experiment reliability. This work proposes a data-driven nowcasting approach to estimate missing plasma density signals using alternative sensor inputs, specifically validated for Electron Cyclotron Resonance Heating (ECRH) regimes. Our methodology uses a Two-Stage Learning Framework that integrates a Variational Autoencoder for latent feature extraction with Recurrent Neural Network blocks and a Multi-Head Attention mechanism. This architecture is designed to capture long-range temporal dependencies by broadcasting a single latent representation across multiple time steps, thus merging local and global temporal features. Extensive experiments on 201 ECRH-heated discharges from the TJ-II dataset demonstrate that deeper recurrent architectures, particularly those employing Long Short-Term Memory units, significantly outperform alternative models in nowcasting plasma density. The best-performing model achieves superior accuracy with a Weighted Mean Absolute Percentage Error (WMAPE) of 0.0328, complemented by low mean squared error and high coefficients of determination. This proof-of-concept study demonstrates the technical feasibility of deep learning-based nowcasting for diagnostic substitution in well-controlled ECRH operational conditions, establishing a methodological foundation for future extension to broader stellarator regimes.
{"title":"A data-driven approach to estimate plasma density in TJ-II stellarator","authors":"Paulo Aguayo , Gonzalo Farias , Alejandro González-Ganzábal , Ernesto Fabregas , Teresa Estrada , Boudewijn van Milligen , Alfonso Baciero , Belén López-Miranda , Francisco Medina , Giuseppe A. Rattá Gutiérrez","doi":"10.1016/j.fusengdes.2025.115596","DOIUrl":"10.1016/j.fusengdes.2025.115596","url":null,"abstract":"<div><div>Magnetically confined fusion devices, such as the stellarator TJ-II, are highly complex infrastructures where plasma evolution is monitored through advanced diagnostic systems. Failures in these diagnostics can result in missing or unreliable data, compromising operational stability and experiment reliability. This work proposes a data-driven nowcasting approach to estimate missing plasma density signals using alternative sensor inputs, specifically validated for Electron Cyclotron Resonance Heating (ECRH) regimes. Our methodology uses a Two-Stage Learning Framework that integrates a Variational Autoencoder for latent feature extraction with Recurrent Neural Network blocks and a Multi-Head Attention mechanism. This architecture is designed to capture long-range temporal dependencies by broadcasting a single latent representation across multiple time steps, thus merging local and global temporal features. Extensive experiments on 201 ECRH-heated discharges from the TJ-II dataset demonstrate that deeper recurrent architectures, particularly those employing Long Short-Term Memory units, significantly outperform alternative models in nowcasting plasma density. The best-performing model achieves superior accuracy with a Weighted Mean Absolute Percentage Error (WMAPE) of 0.0328, complemented by low mean squared error and high coefficients of determination. This proof-of-concept study demonstrates the technical feasibility of deep learning-based nowcasting for diagnostic substitution in well-controlled ECRH operational conditions, establishing a methodological foundation for future extension to broader stellarator regimes.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"224 ","pages":"Article 115596"},"PeriodicalIF":2.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145799074","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 : 2026-03-01Epub Date: 2025-12-15DOI: 10.1016/j.fusengdes.2025.115583
S. Stemmley , B. Moore , D. O’Dea , R. Trendler , P.F. Buxton , P. Bunting , K. Moshkunov , M. Gryaznevich , D.N. Ruzic
Liquid lithium as a plasma-facing material has been shown to be beneficial to the performance of fusion plasmas due to it being low-Z and its strong gettering ability. A design that allows lithium to be circulated and cleaned ensures that lithium does not become saturated with fusion fuel and impurities. A liquid lithium loop has been developed at the University of Illinois with custom pumps and flowmeters to implement recirculating flow on a free-surface plasma-facing component. To de-risk and calibrate these components, a U-shaped vacuum chamber was constructed, enabling lithium to be pumped from a large reservoir tank, through a flowmeter, and into a level measurement chamber. A custom liquid level probe based on time domain reflectometry (TDR) with a 3 mm spatial resolution and a 1 ms temporal resolution was designed and constructed. The TDR probe was calibrated ex-situ and then used to calibrate the voltage signal from a direct current (DC) conduction flowmeter. The liquid level in the U-shaped vacuum chamber was measured as a function of time, allowing the mass flow rate of the lithium to be measured and matched to the flowmeter voltage signal. Flow rates up to 10 g s-1 were measured and a calibration factor of µV g-1 s was determined for the custom DC conduction flowmeter.
液态锂作为等离子体表面材料，由于其低z和强吸散能力，已被证明有利于聚变等离子体的性能。允许锂循环和清洁的设计确保锂不会因聚变燃料和杂质而饱和。伊利诺伊大学（University of Illinois）开发了一种液体锂回路，配备了定制泵和流量计，可以在自由表面等离子体组件上实现再循环流动。为了降低风险并校准这些组件，设计了一个u形真空室，可以将锂从大型储液罐中抽出，通过流量计进入液位测量室。设计并制作了空间分辨率为3mm、时间分辨率为1ms的基于时域反射的定制液位探头。TDR探头在非原位校准，然后用于校准直流（DC）传导流量计的电压信号。测量u形真空室中的液位作为时间的函数，从而测量锂的质量流量，并与流量计电压信号匹配。测量了高达10 g s-1的流量，并确定了定制直流传导流量计的校准因子为158±13µV g-1 s。
{"title":"Time domain reflectometry liquid level probe for the calibration of liquid lithium direct current conduction flowmeters","authors":"S. Stemmley , B. Moore , D. O’Dea , R. Trendler , P.F. Buxton , P. Bunting , K. Moshkunov , M. Gryaznevich , D.N. Ruzic","doi":"10.1016/j.fusengdes.2025.115583","DOIUrl":"10.1016/j.fusengdes.2025.115583","url":null,"abstract":"<div><div>Liquid lithium as a plasma-facing material has been shown to be beneficial to the performance of fusion plasmas due to it being low-Z and its strong gettering ability. A design that allows lithium to be circulated and cleaned ensures that lithium does not become saturated with fusion fuel and impurities. A liquid lithium loop has been developed at the University of Illinois with custom pumps and flowmeters to implement recirculating flow on a free-surface plasma-facing component. To de-risk and calibrate these components, a U-shaped vacuum chamber was constructed, enabling lithium to be pumped from a large reservoir tank, through a flowmeter, and into a level measurement chamber. A custom liquid level probe based on time domain reflectometry (TDR) with a 3<!--> <!-->mm spatial resolution and a 1<!--> <!-->ms temporal resolution was designed and constructed. The TDR probe was calibrated ex-situ and then used to calibrate the voltage signal from a direct current (DC) conduction flowmeter. The liquid level in the U-shaped vacuum chamber was measured as a function of time, allowing the mass flow rate of the lithium to be measured and matched to the flowmeter voltage signal. Flow rates up to 10<!--> <!-->g<!--> <!-->s<sup>-1</sup> were measured and a calibration factor of <span><math><mrow><mn>158</mn><mo>±</mo><mn>13</mn></mrow></math></span> µV<!--> <!-->g<sup>-1</sup> <!-->s was determined for the custom DC conduction flowmeter.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"224 ","pages":"Article 115583"},"PeriodicalIF":2.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145799073","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 : 2026-03-01Epub Date: 2025-12-22DOI: 10.1016/j.fusengdes.2025.115597
N. Rispoli , A. Pecorelli , L. Figini , C. Sozzi , D. Busi , F. Braghin , E. Alessi
The reduction or suppression of magneto-hydrodynamic instabilities, such as Neoclassical Tearing Modes (NTMs), can be performed through localized current driven by Electron Cyclotron Heating and Current Drive (ECH&CD). In this paper, we show that the proper aiming of a steerable antenna can be obtained using a suitable layout of an array of Electron Cyclotron Emission diagnostics (ECE imaging). The diagnostic principle leading to the adoption of ECE imaging is to exploit propagation reciprocity at electron cyclotron frequencies, which allows for the implementation of control strategies such as the In-Line (van den Brand et al., 2018) and the Quasi-In-Line (Sozzi et al., 2023) control schemes (I-L and Q-I-L schemes). However, these schemes require equipping a dedicated ECE diagnostic with at least a movable antenna.
This contribution is based on simulations obtained for a DEMO-like reactor to demonstrate the feasibility of NTM control schemes based on information provided by an ECE imaging diagnostic, which uses a set of fixed Lines-of-Sight (LoS). Towards the design of a diagnostic layout suitable for the use in real machines, the following questions are here addressed: First, we evaluate the number of LoS required to satisfy the strict alignment precision necessary in a DEMO-like reactor and then provide a pre-conceptual design. Finally, the performance that could be obtained by a control system adopting such a diagnostic is evaluated and compared with the I-L and the Q-I-L schemes mentioned above.
通过电子回旋加热和电流驱动（ECH&；CD）驱动的局部电流，可以降低或抑制磁流体动力学不稳定性，如新经典撕裂模式（ntm）。在本文中，我们证明了通过电子回旋发射诊断阵列（ECE成像）的适当布局可以获得适当的定向天线。采用ECE成像的诊断原理是利用电子回旋频率下的传播互易性，这允许实施控制策略，如在线（van den Brand等人，2018）和准在线（Sozzi等人，2023）控制方案（I-L和Q-I-L方案）。然而，这些方案需要配备一个专用的ECE诊断设备，至少有一个可移动的天线。这一贡献是基于对demo样反应器的模拟，以证明基于ECE成像诊断提供的信息的NTM控制方案的可行性，该诊断使用一组固定的视线（LoS）。为了设计适合实际机器使用的诊断布局，这里解决了以下问题：首先，我们评估了满足演示式反应器所需的严格对准精度所需的LoS数量，然后提供了一个概念前设计。最后，对采用这种诊断方法的控制系统所能获得的性能进行了评估，并与上述的I-L和Q-I-L方案进行了比较。
{"title":"Pre-conceptual design of ECE Imaging for real time NTM control","authors":"N. Rispoli , A. Pecorelli , L. Figini , C. Sozzi , D. Busi , F. Braghin , E. Alessi","doi":"10.1016/j.fusengdes.2025.115597","DOIUrl":"10.1016/j.fusengdes.2025.115597","url":null,"abstract":"<div><div>The reduction or suppression of magneto-hydrodynamic instabilities, such as Neoclassical Tearing Modes (NTMs), can be performed through localized current driven by Electron Cyclotron Heating and Current Drive (ECH&CD). In this paper, we show that the proper aiming of a steerable antenna can be obtained using a suitable layout of an array of Electron Cyclotron Emission diagnostics (ECE imaging). The diagnostic principle leading to the adoption of ECE imaging is to exploit propagation reciprocity at electron cyclotron frequencies, which allows for the implementation of control strategies such as the In-Line (van den Brand et al., 2018) and the Quasi-In-Line (Sozzi et al., 2023) control schemes (I-L and Q-I-L schemes). However, these schemes require equipping a dedicated ECE diagnostic with at least a movable antenna.</div><div>This contribution is based on simulations obtained for a DEMO-like reactor to demonstrate the feasibility of NTM control schemes based on information provided by an ECE imaging diagnostic, which uses a set of fixed Lines-of-Sight (LoS). Towards the design of a diagnostic layout suitable for the use in real machines, the following questions are here addressed: First, we evaluate the number of LoS required to satisfy the strict alignment precision necessary in a DEMO-like reactor and then provide a pre-conceptual design. Finally, the performance that could be obtained by a control system adopting such a diagnostic is evaluated and compared with the I-L and the Q-I-L schemes mentioned above.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"224 ","pages":"Article 115597"},"PeriodicalIF":2.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145841354","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}
The ADITYA tokamak, a medium-sized device with a limiter configuration is upgraded to ADITYA-U tokamak with divertor configuration for shaped plasma operation. Three pairs of divertor coils and two pairs of position control coils are introduced in ADITYA-U tokamak. The strategy was focused on optimising the available space for new magnetic field coils installation without relying on the active cooling arrangements. The primary challenge was to install the coil along with the bus bar without any joints while utilizing the same conductor. The demountable TF coils in ADITYA-U tokamak simplified the feasibility for the new coils. The physical and technical boundary conditions were met using copper-based continuous transposed conductor (CTC) for the in-situ coil winding. This simple design is low cost and offers winding flexibility while ensuring accurate coil dimensions. A detailed description of the assembly procedure and solution to different engineering challenges during the fabrication of the divertor and position control coils are presented in this paper.
{"title":"Strategies and solutions for engineering challenges during the assembly of divertor and position control coils in ADITYA-U tokamak","authors":"Rohit Kumar , Vaibhav Ranjan , Harshita Raj , Kumarpal Jadeja , Kaushal Patel , R.L. Tanna , J. Ghosh","doi":"10.1016/j.fusengdes.2026.115615","DOIUrl":"10.1016/j.fusengdes.2026.115615","url":null,"abstract":"<div><div>The ADITYA tokamak, a medium-sized device with a limiter configuration is upgraded to ADITYA-U tokamak with divertor configuration for shaped plasma operation. Three pairs of divertor coils and two pairs of position control coils are introduced in ADITYA-U tokamak. The strategy was focused on optimising the available space for new magnetic field coils installation without relying on the active cooling arrangements. The primary challenge was to install the coil along with the bus bar without any joints while utilizing the same conductor. The demountable TF coils in ADITYA-U tokamak simplified the feasibility for the new coils. The physical and technical boundary conditions were met using copper-based continuous transposed conductor (CTC) for the in-situ coil winding. This simple design is low cost and offers winding flexibility while ensuring accurate coil dimensions. A detailed description of the assembly procedure and solution to different engineering challenges during the fabrication of the divertor and position control coils are presented in this paper.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"224 ","pages":"Article 115615"},"PeriodicalIF":2.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145977565","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 : 2026-03-01Epub Date: 2026-01-09DOI: 10.1016/j.fusengdes.2025.115612
Svitlana Rudchenko , Yiran Mao , Wolfgang Pantleon
Tungsten-based materials are considered as armor of plasma-facing components for future fusion reactors. To mitigate the brittleness of tungsten, tungsten fiber-reinforced tungsten composites (Wf/W) have been developed. Two types of Wf/W composites, with either continuous, aligned, potassium-doped tungsten wires in a dense tungsten matrix or randomly oriented, short fibers in a porous tungsten matrix are investigated. Both were fabricated using a powder metallurgical route facilitating field assisted sintering technology (FAST). Specimens are annealed at 1450 °C for different amounts of time up to two weeks to assess the thermal stability of the composites. Scanning electron microscopy and electron backscatter diffraction reveal major changes in the microstructure. After 4 hours of annealing initiation of recrystallization in the fibers concurrent to grain growth in the matrix is observed in both composites. Recrystallization commences at the outskirts of the fibers causing formation of a rim of small, recrystallized grains. Longer annealing increases the rim of recrystallized grains inwards into the fiber. After 3 days of annealing, all fibers are completely recrystallized, and the matrix is coarsened significantly by grain growth. While the short fibers can still be identified in the porous matrix after one week of annealing, matrix and continuous fibers cannot be distinguished any longer in the dense matrix. Short fibers with large, recrystallized grains can still be recognized after 2 weeks of annealing, while the porous matrix disintegrates by particle coarsening.
{"title":"Thermal stability of tungsten fiber-reinforced tungsten composites fabricated by powder metallurgy","authors":"Svitlana Rudchenko , Yiran Mao , Wolfgang Pantleon","doi":"10.1016/j.fusengdes.2025.115612","DOIUrl":"10.1016/j.fusengdes.2025.115612","url":null,"abstract":"<div><div>Tungsten-based materials are considered as armor of plasma-facing components for future fusion reactors. To mitigate the brittleness of tungsten, tungsten fiber-reinforced tungsten composites (W<sub>f</sub>/W) have been developed. Two types of W<sub>f</sub>/W composites, with either continuous, aligned, potassium-doped tungsten wires in a dense tungsten matrix or randomly oriented, short fibers in a porous tungsten matrix are investigated. Both were fabricated using a powder metallurgical route facilitating field assisted sintering technology (FAST). Specimens are annealed at 1450 °C for different amounts of time up to two weeks to assess the thermal stability of the composites. Scanning electron microscopy and electron backscatter diffraction reveal major changes in the microstructure. After 4 hours of annealing initiation of recrystallization in the fibers concurrent to grain growth in the matrix is observed in both composites. Recrystallization commences at the outskirts of the fibers causing formation of a rim of small, recrystallized grains. Longer annealing increases the rim of recrystallized grains inwards into the fiber. After 3 days of annealing, all fibers are completely recrystallized, and the matrix is coarsened significantly by grain growth. While the short fibers can still be identified in the porous matrix after one week of annealing, matrix and continuous fibers cannot be distinguished any longer in the dense matrix. Short fibers with large, recrystallized grains can still be recognized after 2 weeks of annealing, while the porous matrix disintegrates by particle coarsening.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"224 ","pages":"Article 115612"},"PeriodicalIF":2.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145939618","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 : 2026-03-01Epub Date: 2025-12-17DOI: 10.1016/j.fusengdes.2025.115593
Sixiang Zhao , Binghua Ren , Yuan Zhang
Joining the W/Cu flat tiles fabricated with vacuum casting to RAFM steel via brazing provides an alternative route for blanket manufacturing. Reducing the thickness of pure Cu in W/Cu tiles is favorable from the perspective of minimizing neutron irradiation-induced activation, and obtaining proper microstructures and properties of RAFM steel after the brazing thermal cycle is vital for component commissioning. This study concerns the above issues. The screening experiment reveals that the pure Cu layer is susceptible to alloying with elements that migrated from CuNiMn filler metal. By reducing the thickness of the original Cu layer in the W/Cu tiles to 0.15 ± 0.05 mm through machining, a small-scale mock-up has been successfully brazed. The retained pure Cu layer has a thickness of ∼90 μm, and results show that it can effectively relax thermal stresses. The RAFM steel subjected to the brazing thermal cycle contains less martensite than that heat-treated according to the recommended regulations. Our discussion indicates that this problem can be solved by introducing an enhanced cooling method, which can provide a constant cooling rate while preventing interfacial cracking, or by adopting an RAFM steel requiring a smaller critical cooling rate.
{"title":"Brazing between W/Cu flat tiles and RAFM steel considering the thickness limit of Cu layer and the microscopic evolution of RAFM","authors":"Sixiang Zhao , Binghua Ren , Yuan Zhang","doi":"10.1016/j.fusengdes.2025.115593","DOIUrl":"10.1016/j.fusengdes.2025.115593","url":null,"abstract":"<div><div>Joining the W/Cu flat tiles fabricated with vacuum casting to RAFM steel via brazing provides an alternative route for blanket manufacturing. Reducing the thickness of pure Cu in W/Cu tiles is favorable from the perspective of minimizing neutron irradiation-induced activation, and obtaining proper microstructures and properties of RAFM steel after the brazing thermal cycle is vital for component commissioning. This study concerns the above issues. The screening experiment reveals that the pure Cu layer is susceptible to alloying with elements that migrated from CuNiMn filler metal. By reducing the thickness of the original Cu layer in the W/Cu tiles to 0.15 ± 0.05 mm through machining, a small-scale mock-up has been successfully brazed. The retained pure Cu layer has a thickness of ∼90 μm, and results show that it can effectively relax thermal stresses. The RAFM steel subjected to the brazing thermal cycle contains less martensite than that heat-treated according to the recommended regulations. Our discussion indicates that this problem can be solved by introducing an enhanced cooling method, which can provide a constant cooling rate while preventing interfacial cracking, or by adopting an RAFM steel requiring a smaller critical cooling rate.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"224 ","pages":"Article 115593"},"PeriodicalIF":2.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145798999","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}
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