Pub Date : 2026-03-01Epub Date: 2026-01-09DOI: 10.1016/j.fusengdes.2025.115613
A. González Ganzábal , G.A. Rattá , T. Estrada , J. Martínez-Fernández , N. Panadero , Á. Cappa , B. López-Miranda , A. Baciero , F. Martín , D. Tafalla , B.P. Van Milligen , F. Medina , Á. de la Peña , S. Dormido-Canto , TJ-II team
Starting in 1997, the stellarator TJ-II has produced valuable scientific data crucial in the study of plasma physics and confinement. In this work, we present a stand-alone, comprehensive database that focuses on the statistical value of the TJ-II data. For this purpose, and comprising 4800 discharges, all the signals and parameters required to characterise the device before a discharge, and the diagnostics that better describe the produced plasma have been included in a database. All these different signals have been curated according to the needs of each signal and synchronised into a unified time frame of interest of 1 ms. Thus, this paper and the presented database fulfil two objectives: an introduction to several TJ-II key signals and diagnostics and a common framework for future works that rely on a strong, statistically tested database, such as the creation of models based on machine learning or data simulations.
{"title":"A comprehensive database of TJ-II signals and diagnostics for statistically based models","authors":"A. González Ganzábal , G.A. Rattá , T. Estrada , J. Martínez-Fernández , N. Panadero , Á. Cappa , B. López-Miranda , A. Baciero , F. Martín , D. Tafalla , B.P. Van Milligen , F. Medina , Á. de la Peña , S. Dormido-Canto , TJ-II team","doi":"10.1016/j.fusengdes.2025.115613","DOIUrl":"10.1016/j.fusengdes.2025.115613","url":null,"abstract":"<div><div>Starting in 1997, the stellarator TJ-II has produced valuable scientific data crucial in the study of plasma physics and confinement. In this work, we present a stand-alone, comprehensive database that focuses on the statistical value of the TJ-II data. For this purpose, and comprising 4800 discharges, all the signals and parameters required to characterise the device before a discharge, and the diagnostics that better describe the produced plasma have been included in a database. All these different signals have been curated according to the needs of each signal and synchronised into a unified time frame of interest of 1 ms. Thus, this paper and the presented database fulfil two objectives: an introduction to several TJ-II key signals and diagnostics and a common framework for future works that rely on a strong, statistically tested database, such as the creation of models based on machine learning or data simulations.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"224 ","pages":"Article 115613"},"PeriodicalIF":2.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145939089","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.2025.115598
Troy Pederson , Himank Anand , Charlie Lasnier , Lennard Ceelen , Jun Ren , Keith Erickson , Ben Penaflor , John Ferron
In future tokamak reactors like ITER and the Fusion Pilot Plant (FPP), real-time feedback control of heat flux to the plasma-facing components (PFC) will be critical for steady-state operation. This work presents the first experimental demonstration of real-time divertor heat flux estimation with infrared thermography and feedback control with impurity seeding on the DIII-D tokamak. The flexible infrastructure of the Plasma Control System (PCS) on DIII-D makes this new capability possible. The PCS software runs on a gateway computer system, and five real-time compute nodes. An array of low latency streaming digitizers from d-TACQ Solutions connects to these real-time computers to collect and process data, and send commands to actuators during plasma discharges. This system handles the signal IO from the tokamak and allows the PCS to utilize the diagnostic data necessary to perform control in real-time. Feedback control on heat flux was accomplished by feeding infrared camera data from the “Infrared TV” (IRTV) camera to a custom-developed User Datagram Protocol (UDP) server. This server transmits infrared data to a newly developed PCS algorithm that estimates the heat flux to PFC. A proportional integral derivative (PID) controller minimizes the error between a heat flux reference and the real-time estimate by injecting nitrogen gas into the divertor.
{"title":"Preliminary proof-of-concept of real-time divertor heat flux control from infrared cameras with nitrogen injection in the DIII-D tokamak","authors":"Troy Pederson , Himank Anand , Charlie Lasnier , Lennard Ceelen , Jun Ren , Keith Erickson , Ben Penaflor , John Ferron","doi":"10.1016/j.fusengdes.2025.115598","DOIUrl":"10.1016/j.fusengdes.2025.115598","url":null,"abstract":"<div><div>In future tokamak reactors like ITER and the Fusion Pilot Plant (FPP), real-time feedback control of heat flux to the plasma-facing components (PFC) will be critical for steady-state operation. This work presents the first experimental demonstration of real-time divertor heat flux estimation with infrared thermography and feedback control with impurity seeding on the DIII-D tokamak. The flexible infrastructure of the Plasma Control System (PCS) on DIII-D makes this new capability possible. The PCS software runs on a gateway computer system, and five real-time compute nodes. An array of low latency streaming digitizers from <span>d</span>-TACQ Solutions connects to these real-time computers to collect and process data, and send commands to actuators during plasma discharges. This system handles the signal IO from the tokamak and allows the PCS to utilize the diagnostic data necessary to perform control in real-time. Feedback control on heat flux was accomplished by feeding infrared camera data from the “Infrared TV” (IRTV) camera to a custom-developed User Datagram Protocol (UDP) server. This server transmits infrared data to a newly developed PCS algorithm that estimates the heat flux to PFC. A proportional integral derivative (PID) controller minimizes the error between a heat flux reference and the real-time estimate by injecting nitrogen gas into the divertor.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"224 ","pages":"Article 115598"},"PeriodicalIF":2.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145939617","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: 2026-01-06DOI: 10.1016/j.fusengdes.2025.115602
B. Kool , M. Lennholm , A. Parrott , P.A. Figueiredo , G.L. Derks , O.P. Bardsley , M. Lord , A. Cureton , S.S. Henderson , N.J. Conway , J. Lovell , T.A. Wijkamp , N. Lonigro , S.P. Kobussen , L. Ceelen , K. Verhaegh , M. van Berkel , STEP team , MAST-U team , EUROfusion Tokamak Exploitation Team
This work explores the challenges and opportunities for power exhaust control in STEP, informed by dedicated MAST-U experiments. The STEP system primarily relies on hydrogenic and argon gas injection into the divertors, compensating for transients originating in the plasma core. Fast transients (10 Hz) that evolve too quickly for actuators to compensate must be absorbed passively; the enhanced transient buffering of the foreseen long-legged divertor provides a clear advantage over conventional geometries, as demonstrated in the MAST-U Super-X divertor. Experiments further indicate that STEP’s tight divertor baffling enables near-independent control of the upper and lower divertors. The most challenging transients are expected from power-sharing fluctuations, as MAST-U experiments observed extremely fast dynamics. Fluctuations from core pellet fuelling remain relatively benign due to the small pellet size according to simulations. Exhaust control in a reactor like STEP requires an integrated approach befitting its machine-critical nature. A predictive control element, integrated with core plasma control, allows pre-emptive preparation of the divertor for incoming transients. An observer-based diagnostic approach is foreseen to monitor the divertor in the challenging reactor environment, supported by an extended diagnostic set in the non-nuclear phase to validate the required dynamic models.
{"title":"From MAST-U to STEP: Power exhaust control challenges and opportunities","authors":"B. Kool , M. Lennholm , A. Parrott , P.A. Figueiredo , G.L. Derks , O.P. Bardsley , M. Lord , A. Cureton , S.S. Henderson , N.J. Conway , J. Lovell , T.A. Wijkamp , N. Lonigro , S.P. Kobussen , L. Ceelen , K. Verhaegh , M. van Berkel , STEP team , MAST-U team , EUROfusion Tokamak Exploitation Team","doi":"10.1016/j.fusengdes.2025.115602","DOIUrl":"10.1016/j.fusengdes.2025.115602","url":null,"abstract":"<div><div>This work explores the challenges and opportunities for power exhaust control in STEP, informed by dedicated MAST-U experiments. The STEP system primarily relies on hydrogenic and argon gas injection into the divertors, compensating for transients originating in the plasma core. Fast transients (<span><math><mo>></mo></math></span>10 Hz) that evolve too quickly for actuators to compensate must be absorbed passively; the enhanced transient buffering of the foreseen long-legged divertor provides a clear advantage over conventional geometries, as demonstrated in the MAST-U Super-X divertor. Experiments further indicate that STEP’s tight divertor baffling enables near-independent control of the upper and lower divertors. The most challenging transients are expected from power-sharing fluctuations, as MAST-U experiments observed extremely fast dynamics. Fluctuations from core pellet fuelling remain relatively benign due to the small pellet size according to simulations. Exhaust control in a reactor like STEP requires an integrated approach befitting its machine-critical nature. A predictive control element, integrated with core plasma control, allows pre-emptive preparation of the divertor for incoming transients. An observer-based diagnostic approach is foreseen to monitor the divertor in the challenging reactor environment, supported by an extended diagnostic set in the non-nuclear phase to validate the required dynamic models.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"224 ","pages":"Article 115602"},"PeriodicalIF":2.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145939616","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: 2025-12-23DOI: 10.1016/j.fusengdes.2025.115600
Sa-Woong Kim , Jun-Sung Chang , Ji-Young Jeong , Duck-Hoi Kim
Active water cooling is designed to remove the nuclear heat generation in the Shield Block (SB). In some modules, the surface heat flux is also considered due to lack of First Wall (FW) coverage. According to the manufacturability assessment, the cooling channels in the SB are made by drilling process because it is preferable to manufacture the SBs from one single stainless steel forged block. The water headers are machined on the side of the SB, and closed by cover plates which have a thickness from 8 mm to 10 mm.
In this study, it is present a novel hybrid welding technique that combines the advantages of manual welding and robotic welding to address the unique challenges posed by conventional manual TIG welding. Manual TIG welding offers the flexibility and applicability required for variable weld geometries, while robotic welding provides the benefits of precision, repeatability, and increased productivity.
The development of the A-M combined welding process involves optimizing parameters such as welding speed, heat input and arc stability to achieve a seamless integration of manual and robotic welding techniques. Additionally, considerations for joint accessibility, weld quality and overall process efficiency are addressed to ensure the successful application of the hybrid approach in a complex welding environment.
The proposed approach not only meets the stringent requirements of ITER components but also provides a versatile solution that can be adapted to similar applications in advanced manufacturing scenarios.
{"title":"Development and application of A-M combined TIG welding techniques for the ITER Blanket Shield Block","authors":"Sa-Woong Kim , Jun-Sung Chang , Ji-Young Jeong , Duck-Hoi Kim","doi":"10.1016/j.fusengdes.2025.115600","DOIUrl":"10.1016/j.fusengdes.2025.115600","url":null,"abstract":"<div><div>Active water cooling is designed to remove the nuclear heat generation in the Shield Block (SB). In some modules, the surface heat flux is also considered due to lack of First Wall (FW) coverage. According to the manufacturability assessment, the cooling channels in the SB are made by drilling process because it is preferable to manufacture the SBs from one single stainless steel forged block. The water headers are machined on the side of the SB, and closed by cover plates which have a thickness from 8 mm to 10 mm.</div><div>In this study, it is present a novel hybrid welding technique that combines the advantages of manual welding and robotic welding to address the unique challenges posed by conventional manual TIG welding. Manual TIG welding offers the flexibility and applicability required for variable weld geometries, while robotic welding provides the benefits of precision, repeatability, and increased productivity.</div><div>The development of the A-M combined welding process involves optimizing parameters such as welding speed, heat input and arc stability to achieve a seamless integration of manual and robotic welding techniques. Additionally, considerations for joint accessibility, weld quality and overall process efficiency are addressed to ensure the successful application of the hybrid approach in a complex welding environment.</div><div>The proposed approach not only meets the stringent requirements of ITER components but also provides a versatile solution that can be adapted to similar applications in advanced manufacturing scenarios.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"224 ","pages":"Article 115600"},"PeriodicalIF":2.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145841353","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: 2026-01-12DOI: 10.1016/j.fusengdes.2026.115624
J.Q. Wang , Y.P. Zhang , Z.B. Wang , Y.X. Han , Z.H. Wang , J. Chen , Y. Yu , J. Zhang , C.Y. Zhao , H.Y. Shen , H. Duan , Q.L. Yang , H.B. Xu , HL-3 Team
A high spatiotemporal resolution hard X-ray (HXR) camera system has been designed for HL-3 tokamak for detecting fast electron bremsstrahlung and runaway electron profile imaging. By utilizing a combination of yttrium oxyorthosilicate (YSO) scintillator and silicon photomultipliers (SiPM), the system achieves a time resolution of up to 1 ms. Through the rational arrangement of scintillators, the camera can simultaneously detect 100 channels of hard X-rays, resulting in a spatial resolution of 2 cm for the camera. The system is dedicated to study the runaway electrons in the hard X-ray energy range of 20 to 200 keV. By improving the time resolution to 1 ms, it can be used to study power deposition in lower hybrid current drive (LHCD) and electron cyclotron resonance heating (ECRH), the generation of runaway seed populations in plasmas, and behavior of runaway electrons during plasma disruptions. The experimental results can present the evolution over time and the spatial distribution. This paper presents the system design, performance and typical diagnostic results.
{"title":"Design of a high spatiotemporal resolution hard X-ray camera system on the HL-3 tokamak","authors":"J.Q. Wang , Y.P. Zhang , Z.B. Wang , Y.X. Han , Z.H. Wang , J. Chen , Y. Yu , J. Zhang , C.Y. Zhao , H.Y. Shen , H. Duan , Q.L. Yang , H.B. Xu , HL-3 Team","doi":"10.1016/j.fusengdes.2026.115624","DOIUrl":"10.1016/j.fusengdes.2026.115624","url":null,"abstract":"<div><div>A high spatiotemporal resolution hard X-ray (HXR) camera system has been designed for HL-3 tokamak for detecting fast electron bremsstrahlung and runaway electron profile imaging. By utilizing a combination of yttrium oxyorthosilicate (YSO) scintillator and silicon photomultipliers (SiPM), the system achieves a time resolution of up to 1 ms. Through the rational arrangement of scintillators, the camera can simultaneously detect 100 channels of hard X-rays, resulting in a spatial resolution of 2 cm for the camera. The system is dedicated to study the runaway electrons in the hard X-ray energy range of 20 to 200 keV. By improving the time resolution to 1 ms, it can be used to study power deposition in lower hybrid current drive (LHCD) and electron cyclotron resonance heating (ECRH), the generation of runaway seed populations in plasmas, and behavior of runaway electrons during plasma disruptions. The experimental results can present the evolution over time and the spatial distribution. This paper presents the system design, performance and typical diagnostic results.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"224 ","pages":"Article 115624"},"PeriodicalIF":2.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145977553","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: 2025-12-30DOI: 10.1016/j.fusengdes.2025.115607
Kaiyang Yi , Zhihui Huang , Weice Wang , Jun Cheng , Na Wu , Yu He , Wei Zhao , Lin Nie , Longwen Yan , Guoliang Xiao , Zhongbing Shi , Xiaoquan Ji , Wulyu Zhong
This paper introduces the mid-plane fast reciprocating probe (FRP) system in the HL-3 tokamak. Unlike traditional pneumatic cylinder or servo motor drives, this system achieves fast movement through the operation of a linear motor and a counterweight cabinet. The counterweight cabinet is chosen to balance the atmospheric pressure for the first time, without requiring a large linear motor with high output torque. As a result, the system takes up less space and has high speed, high acceleration, long stroke length, and adjustable movement distance. The front of this system can accommodate various compound probes with a maximum pin number of 19. At present, this system has been put into operation in the HL-3 tokamak, and preliminary experimental results confirm the novel design.
{"title":"Fast reciprocating probe system with synergistic operation of a small linear motor and a counterweight cabinet on HL-3","authors":"Kaiyang Yi , Zhihui Huang , Weice Wang , Jun Cheng , Na Wu , Yu He , Wei Zhao , Lin Nie , Longwen Yan , Guoliang Xiao , Zhongbing Shi , Xiaoquan Ji , Wulyu Zhong","doi":"10.1016/j.fusengdes.2025.115607","DOIUrl":"10.1016/j.fusengdes.2025.115607","url":null,"abstract":"<div><div>This paper introduces the mid-plane fast reciprocating probe (FRP) system in the HL-3 tokamak. Unlike traditional pneumatic cylinder or servo motor drives, this system achieves fast movement through the operation of a linear motor and a counterweight cabinet. The counterweight cabinet is chosen to balance the atmospheric pressure for the first time, without requiring a large linear motor with high output torque. As a result, the system takes up less space and has high speed, high acceleration, long stroke length, and adjustable movement distance. The front of this system can accommodate various compound probes with a maximum pin number of 19. At present, this system has been put into operation in the HL-3 tokamak, and preliminary experimental results confirm the novel design.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"224 ","pages":"Article 115607"},"PeriodicalIF":2.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145884842","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: 2026-01-06DOI: 10.1016/j.fusengdes.2025.115599
P. Molina-Cabrera, F. Pastore, A. Frank, L. Simons, A. Tourneur, C. Yildiz, B. Vincent, K. Verhaegh, C. Marini, M. Wensing, A. Ianchenko, A. Balestri, S. Ernst, S. Coda, U. Sheikh, the TCV team
{"title":"Corrigendum to “Improvements to standard diagnostic preparation and data-quality monitoring in the TCV tokamak” [Fusion Engineering and Design, Volume 223, February 2026, 115578]","authors":"P. Molina-Cabrera, F. Pastore, A. Frank, L. Simons, A. Tourneur, C. Yildiz, B. Vincent, K. Verhaegh, C. Marini, M. Wensing, A. Ianchenko, A. Balestri, S. Ernst, S. Coda, U. Sheikh, the TCV team","doi":"10.1016/j.fusengdes.2025.115599","DOIUrl":"10.1016/j.fusengdes.2025.115599","url":null,"abstract":"","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"224 ","pages":"Article 115599"},"PeriodicalIF":2.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146188594","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: 2025-12-30DOI: 10.1016/j.fusengdes.2025.115604
Zheng Fang , Hao Cheng , Bing Zhou , Baoping Gong , Zhenzhong Li , Qiang Lian , Shanshan Bu , Deqi Chen
During long-term operation of tritium breeding blankets in fusion reactors, breeder particles are subjected to both irradiation and thermal stress, which can lead to particle fracture, thereby affecting the structural integrity of the pebble bed and the tritium breeding performance. This study investigates the fracture behavior of Li₄SiO₄ particles used in Helium-Cooled Ceramic Breeder (HCCB) blankets. In this work, Uniaxial cyclic compression tests were performed on breeder pebble beds to evaluate their mechanical response under different stress and temperature conditions. The particle breakage rate and fragment size distribution were obtained through sieving. Results indicated that increasing compressive stress and temperature led to higher breakage rates and a greater mass fraction of small fragments. Building on these fragmentation characteristics, multiple crushed packed beds with varying breakage rates (3–15%) and size distributions were configured to investigate particle breakage effects on purge-gas pressure drops, revealing that the helium pressure drop increases with the breakage rate. Crucially, the Ergun equation reliably predicted pressure drops for breakage rates ≤15%, with a maximum deviation of 10.6% under extreme fragmentation.
{"title":"Experimental study on particle crushing and pressure drop characteristics of Li4SiO4 breeder pebble beds","authors":"Zheng Fang , Hao Cheng , Bing Zhou , Baoping Gong , Zhenzhong Li , Qiang Lian , Shanshan Bu , Deqi Chen","doi":"10.1016/j.fusengdes.2025.115604","DOIUrl":"10.1016/j.fusengdes.2025.115604","url":null,"abstract":"<div><div>During long-term operation of tritium breeding blankets in fusion reactors, breeder particles are subjected to both irradiation and thermal stress, which can lead to particle fracture, thereby affecting the structural integrity of the pebble bed and the tritium breeding performance. This study investigates the fracture behavior of Li₄SiO₄ particles used in Helium-Cooled Ceramic Breeder (HCCB) blankets. In this work, Uniaxial cyclic compression tests were performed on breeder pebble beds to evaluate their mechanical response under different stress and temperature conditions. The particle breakage rate and fragment size distribution were obtained through sieving. Results indicated that increasing compressive stress and temperature led to higher breakage rates and a greater mass fraction of small fragments. Building on these fragmentation characteristics, multiple crushed packed beds with varying breakage rates (3–15%) and size distributions were configured to investigate particle breakage effects on purge-gas pressure drops, revealing that the helium pressure drop increases with the breakage rate. Crucially, the Ergun equation reliably predicted pressure drops for breakage rates ≤15%, with a maximum deviation of 10.6% under extreme fragmentation.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"224 ","pages":"Article 115604"},"PeriodicalIF":2.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145884862","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: 2025-12-27DOI: 10.1016/j.fusengdes.2025.115605
Yiran Mao , Jan Willem Coenen , Johann Riesch , Thomas Schwarz-Selinger , Elena Tejado , Arkadi Kreter , Alexis Terra , Marius Wirtz , Marcin Rasinski , Juan Du , Xiaoyue Tan , Yaohui Liu , Rudolf Neu , Christoph Broeckmann , Christian Linsmeier
For future fusion devices, tungsten is the main candidate materials for the application as plasma facing materials (PFMs). However, considering the challenging operational condition with high thermal loading/thermal stress combining plasma exposure and neutron irradiation/embrittlement, one of the major concern for tungsten as PFMs is its intrinsic brittleness. To avoid cracking and components failure, toughening tungsten is widely investigated, among which tungsten fiber reinforced tungsten composites (Wf/W) are developed using an extrinsic toughening mechanism. Recently, a new type of aligned long fiber Wf/W (L-Wf/W) with dedicated weak interface have been prepared by powder metallurgy process, combing the advantages of superb damage resilience with a much easier production compared to conventional chemical vapor deposition process. In this work, the newly developed material is characterized, including, mechanical tests, high heat flux tests, exposure to plasma for erosion and fuel retention tests. The l-Wf/W composite could improve significantly the damage resilience compared to pure W without altering much of other properties.
{"title":"Demonstrating powder metallurgically produced long tungsten fiber-reinforced tungsten composite to serve as plasma-facing material","authors":"Yiran Mao , Jan Willem Coenen , Johann Riesch , Thomas Schwarz-Selinger , Elena Tejado , Arkadi Kreter , Alexis Terra , Marius Wirtz , Marcin Rasinski , Juan Du , Xiaoyue Tan , Yaohui Liu , Rudolf Neu , Christoph Broeckmann , Christian Linsmeier","doi":"10.1016/j.fusengdes.2025.115605","DOIUrl":"10.1016/j.fusengdes.2025.115605","url":null,"abstract":"<div><div>For future fusion devices, tungsten is the main candidate materials for the application as plasma facing materials (PFMs). However, considering the challenging operational condition with high thermal loading/thermal stress combining plasma exposure and neutron irradiation/embrittlement, one of the major concern for tungsten as PFMs is its intrinsic brittleness. To avoid cracking and components failure, toughening tungsten is widely investigated, among which tungsten fiber reinforced tungsten composites (W<sub>f</sub>/W) are developed using an extrinsic toughening mechanism. Recently, a new type of aligned long fiber W<sub>f</sub>/W (L-W<sub>f</sub>/W) with dedicated weak interface have been prepared by powder metallurgy process, combing the advantages of superb damage resilience with a much easier production compared to conventional chemical vapor deposition process. In this work, the newly developed material is characterized, including, mechanical tests, high heat flux tests, exposure to plasma for erosion and fuel retention tests. The <span>l</span>-W<sub>f</sub>/W composite could improve significantly the damage resilience compared to pure W without altering much of other properties.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"224 ","pages":"Article 115605"},"PeriodicalIF":2.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145884844","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.2025.115608
S. Del Nero , P. Fanelli , V. Prost , F.A. Volpe
The performance of high-field magnets is increasingly constrained not by the limits of High-Temperature Superconducting materials, but by the structural systems needed to withstand the intense Electro-Magnetic forces they produce. In response to this challenge, this work presents a design-driven methodology for optimizing the reinforcement structures of 52 cm bore wide HTS magnets under development at Renaissance Fusion, aimed at achieving magnetic fields up to 10 T on the plasma axis. A custom Topology Optimization tool, based on the Solid Isotropic Material Penalization method and implemented entirely in PyMAPDL, was employed to guide the mechanical design of the magnet reinforcements. Starting from a large design domain (11.3 tons per sector), Topology Optimization with varying volume fractions produced lightweight structures, down to 3.93 tons, that meet strict mechanical constraints on magnet displacement (1 mm), magnet strain (0.5%) and global stress (800 MPa). Then, a second optimization stage using extrusion constraints methodologies was employed to further optimize the structure while ensuring manufacturability. Recurring features from these runs informed the development of a parametric model, enabling further refinement and a final mass of 1.20 t. The final structure, segmented into sub-components for a feasible assembly procedure, retained the required mechanical performance while ensuring ease of manufacturing using conventional processes. This magnet design demonstrate the applicability and benefits of our multi-stage constrained topology optimization method for advancing the structural design of high-field and compact stellarators.
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