Fusion Engineering and Design最新文献

{"title":"Ventilated immersive suit for interactive & operative nuclear operations (VISION) applied to ITER test blanket modules","authors":"Stéphane Gazzotti ,&nbsp;Tanguy Sève ,&nbsp;Killian Huc ,&nbsp;Simon Demolin ,&nbsp;Chiara Di Paolo ,&nbsp;Vincent Weistroffer ,&nbsp;Claude Andriot ,&nbsp;Jean-Pierre Friconneau ,&nbsp;Jean-Pierre Martins","doi":"10.1016/j.fusengdes.2025.114889","DOIUrl":"10.1016/j.fusengdes.2025.114889","url":null,"abstract":"<div><div>CEA is conducting feasibility studies on Test Blanket Modules (TBM) replacement operations in ITER Port Cells, employing an innovative validation concept through simulations using Extended Reality (XR). Collaborating with MATISEC (company specialized in production of security equipment for hostile environments), this study addresses nuclear engineering with motivation to assess in early design phase the use of Personnel Protection Equipment. This study also focusses on the new Immersive Air-Fed Suit (AFS) tailored for XR simulations to prepare hands on operations in hazardous environment. To address the increased operator's workload and fatigue associated with AFS use, the concept uses a modified MATISEC MRV5 prototype. It incorporates internal and external sensors, inertial units, optical and posture sensors, instrumented gloves and depth cameras. Integrated with the XDE physics engine(interactive physics engine) from CEA LIST (Laboratory for Integration of Systems and Technology), these components form an interactive simulation enabling to perform technical tasks in a virtual environment. The virtual simulation replicates human behavior and accurately simulates assembling/disassembling insulation, flanges or cutting/welding pipes operations with scale one tangible tools. The augmented suit and virtual reality resources allow the exploration of intervention scenarios, aligning with French labor regulations limiting AFS use due to operator fatigue. This technology is implemented in the Virtual Integration Platform for Engineering &amp; Remote handling (VIPER) at CEA IRFM (Institute for Magnetic Fusion Research) in Cadarache. This innovative concept allows to check Human Factors requirements early in the design process, integrating advanced monitoring systems for real-time data. Applied to the Pipe Forest accessibility use case for TBM replacement in port cells #16 and #18, it streamlines the design and integration of complex components in constrained working environments minimizing worker exposure in line with the ALARA principle of radiation safety (As Low As Reasonably Achievable). The immersive simulation capabilities position the project as a valuable tool for industries prioritizing worker safety, particularly in nuclear facilities. This innovation extends its applicability to various fields, ranging from engineering analysis to worker training, offering a novel approach to integrate human factors into technical studies.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"214 ","pages":"Article 114889"},"PeriodicalIF":1.9,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143511093","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Design and evaluation of an advanced robotic bolting tool applied to IFMIF-DONES","authors":"V. Redondo,&nbsp;N. Barbosa,&nbsp;P. Espinosa,&nbsp;M. Ferre","doi":"10.1016/j.fusengdes.2025.114877","DOIUrl":"10.1016/j.fusengdes.2025.114877","url":null,"abstract":"<div><div>Operating bolts is a key aspect in most maintenance procedures. This work focuses on IFMIF-DONES (The International Fusion Materials Irradiation Facility - DEMO Oriented Neutron Source being built in Granada), where the radiation conditions require the use of robots for the maintenance procedures and some bolts need to be tightened at high torques to warrant proper functioning during operation.</div><div>The design presented in this contribution consists of a servo motor, a metallic structure, a socket wrench (as the physical interface with the bolt), a spring and a load cell between the motor and the socket wrench (to inform about the fitting of the bolt), and two slots for pins that will act both as reaction torque limiters and guiding system.</div><div>For the evaluation of the tool, a set of validation tests has been carried out in a mock-up developed in the laboratory. It consists of different screws and pins placed in a horizontal plane reachable by the robotic arm. During the experiments, the forces and torques in the joints of the robot are monitored, their analysis is presented in this work.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"214 ","pages":"Article 114877"},"PeriodicalIF":1.9,"publicationDate":"2025-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143488598","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}

{"title":"Kinetic analysis of tritium release from irradiated biphasic lithium ceramics Li4SiO4-Li2TiO3 with different phase ratios","authors":"S. Askerbekov ,&nbsp;Y. Chikhray ,&nbsp;T. Kulsartov ,&nbsp;A. Akhanov ,&nbsp;A. Shaimerdenov ,&nbsp;M. Aitkulov ,&nbsp;Zh. Bugybay ,&nbsp;I. Kenzhina ,&nbsp;Sh. Gizatulin ,&nbsp;R. Knitter ,&nbsp;J. Leys","doi":"10.1016/j.fusengdes.2025.114873","DOIUrl":"10.1016/j.fusengdes.2025.114873","url":null,"abstract":"<div><div>This paper analyzes the kinetics of tritium release from biphasic Li₂TiO₃/Li₄SiO₄ lithium ceramics using thermal desorption spectroscopy after neutron irradiation at the WWR-K reactor. Samples with different Li₂TiO₃ contents (25 mol% and 35 mol%) in the Li₄SiO₄ main phase, fabricated by the KALOS process at the Karlsruhe Institute of Technology, were irradiated at a low temperature and a thermal neutron flux of 2 × 10¹³ n/(cm²·s) during 21.5 effective full power days until accumulating a fluence of 3.7 × 10¹⁹ n/cm².</div><div>The experimental results confirm the significant influence of phase composition on the processes of tritium release. The analysis allowed us to develop a reasonable mechanism of tritium release during linear heating up to 1173 K.</div><div>Tritium was found to be uniformly distributed throughout the ceramic volume and its release is closely related to the microstructural characteristics of the material. Key factors affecting the process include the presence and distribution of traps and defects interacting with the external surface of the sample. The release process of these traps is determined by the transport of tritium to the boundaries, followed by desorption mainly in the form of HT molecules and has three main peaks.</div><div>Samples with 25 mol% Li₂TiO₃ showed high activation energy values, indicating the presence of more stable traps and complex tritium transport pathways. With an increased Li₂TiO₃ content of 35 mol%, a decrease in activation energy was observed, indicating a faster desorption process, probably due to changes in microstructure or the number of active defects facilitating tritium release at lower temperatures.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"214 ","pages":"Article 114873"},"PeriodicalIF":1.9,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143488597","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}

{"title":"EU-DEMO limiters design integration issues and constraints driven by remote maintenance challenges","authors":"M.L. Richiusa ,&nbsp;J. Lyytinen ,&nbsp;A. Sinha ,&nbsp;G.A. Spagnuolo","doi":"10.1016/j.fusengdes.2025.114890","DOIUrl":"10.1016/j.fusengdes.2025.114890","url":null,"abstract":"<div><div>The Limiter (LIM) System of a port-based tokamak like the EU-DEMO encompasses different kinds of limiters for first wall protection purposes. Although the limiters’ position and poloidal surface extension are driven by plasma physics inputs and verified under charged particle heat loads by means of field line tracing, they should also be designed to be easily and independently handled through vacuum vessel ports. Among the four identified types of limiters, four Outboard Lower Limiters (OLL) and four Inboard Midplane Limiters (IML) – when the inboard protection is conceived as a standalone component – do not have dedicated ports for their maintenance, as no vacuum vessel openings are foreseen in the lower outboard first wall, precisely behind the OLL, and behind the IML in the inboard equatorial first wall. On one hand, limiters should be designed to protect the first wall against energy depositions following plasma disruptive events; on the other side, though, it is important to ensure that the protection system is designed under realistic constraints to be easily handled and realistically maintained. Therefore, integration and remote maintenance requirements and needs become an important factor affecting both the OLL and IML integrated engineering design, for which a dedicated handling strategy becomes one of the main drivers, together with physics needs.</div><div>The paper presents the rationale followed for addressing the integration issues which drive the design of limiters with no dedicated ports behind them, and the remote maintenance strategy supporting their design concept. The definition of the handling strategy will help identify robust design drivers that apply to the entire lifecycle of the OLL and IML and improve the feasibility of achieving a practicable design solution compatible with its remote maintenance at every stage.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"214 ","pages":"Article 114890"},"PeriodicalIF":1.9,"publicationDate":"2025-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143464511","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}

{"title":"Feasibility study for cryogenic pellets production with pure gaseous helium cooling for ITER Disruption Mitigation System","authors":"T. Boujet,&nbsp;A. Attard,&nbsp;P. Bonnay,&nbsp;N. Luchier,&nbsp;J. Manzagol,&nbsp;F. Millet","doi":"10.1016/j.fusengdes.2025.114891","DOIUrl":"10.1016/j.fusengdes.2025.114891","url":null,"abstract":"<div><div>CEA/DSBT designed and operated a test bench for pellet injection cooled by liquid helium (LHe) to study the production and the acceleration of large cryogenic pellets for the ITER Disruption Mitigation System (DMS). Large (ø28.5 mm) protium (¹H) pellets of ∼3 g were successfully formed in 20 mins and then accelerated above 500 m/s. However, LHe cooling is not distributed by ITER cryoplant and shall be replaced by supercritical helium (SHe) cooling.</div><div>To evaluate the feasibility of using SHe as a coolant, the CEA/DSBT test bench is modified to operate with pure gaseous helium cooling (GHe at 1.25 bara), which behave more like SHe than LHe used up to now. The main difference between GHe and LHe cooling is the temperature variation induced by the thermal heat removal. In LHe cooling, the heat exchange occurs mainly at a constant temperature due to the liquid to gas phase change (latent heat). In the opposite, in GHe cooling, only the specific heat is available for heat removal, resulting in a cooling temperature increase. Excessive temperature rise is a drawback to the goal of reduced pellet formation times, where the cell temperature must be kept as low as possible.</div><div>This paper presents a comparison of LHe and GHe cooling using the current ∅28.5 mm <em>in-situ</em> condensation cell and highlights some pellet formation key parameters such as the species (pure protium and pure neon or protium/neon mix) and the cold cell temperature. The protium pellets were the most extensively compared, as they are the fastest to produce and the most characterised with LHe cooling. All other types of DMS pellets were also briefly studied. The GHe cooling results show similar pellet formation durations, pellet aspects and speeds as those with LHe cooling. This proof of principle using gaseous cooling is a significant step in the design study of the ITER-DMS cold cell using SHe cooling.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"214 ","pages":"Article 114891"},"PeriodicalIF":1.9,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143453370","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}

{"title":"Improvement of impinging jet heat transfer model for thermal-hydraulic analysis in the vacuum vessel of a fusion reactor","authors":"Jinghua Jiang,&nbsp;Lili Tong,&nbsp;Xuewu Cao","doi":"10.1016/j.fusengdes.2025.114878","DOIUrl":"10.1016/j.fusengdes.2025.114878","url":null,"abstract":"<div><div>In-vessel Loss of Coolant Accident (In-vessel LOCA) in the vacuum vessel of a tokamak fusion reactor, where water is used as the primary coolant, presents a significant challenge. Coolant jets are expected to impinge on high-temperature plasma-facing components (PFCs), resulting in phase transitions on the PFCs surfaces that accelerate pressurization within the vacuum vessel and threaten the chamber's pressure limits. To enhance the predictive capability for pressurization caused by coolant impingement on high-temperature PFCs, the jet impingement heat transfer model must be evaluated and refined. In this study, data from the Ingress of Coolant Event (ICE) experimental setup conducted by the Japan Atomic Energy Research Institute (JAERI) are employed as a benchmark. Initially, a wall heat transfer model based on convective heat transfer is evaluated, revealing a substantial discrepancy between simulation results and experimental data due to the original model's lack of mechanistic considerations, particularly regarding the hysteresis region of impingement heat transfer. Subsequently, two typical jet impingement heat transfer models, developed through experimental and theoretical methods, are introduced. Evaluations indicate that both models underestimate the heat transfer efficiency during coolant impingement on the wall in a vacuum environment, with the Liu model exhibiting errors of approximately 15 % and 10 % for wall temperature and temperature change rate simulations, respectively. The maximum deviation in pressure prediction within the vacuum vessel exceeds 20 %. A theoretical analysis of Helmholtz instability of thin liquid film layer on high-temperature surface in a vacuum environment is then conducted. This analysis considers the enhanced generation of steam under vacuum conditions, leading to a higher steam jet area percentage. Perturbations in the thin liquid film affecting the high-temperature surface are shown to strengthen heat transfer. Based on these findings, a jet impingement heat transfer model tailored for vacuum environments is developed. Comparisons between simulation results and the ICE experimental data demonstrate that the modified model significantly improves predictive accuracy for wall temperature and its rate of change, reducing the pressure prediction error in the vacuum vessel to &lt;10 %.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"214 ","pages":"Article 114878"},"PeriodicalIF":1.9,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143464622","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}

{"title":"SiC detector response to tokamak neutron spectra mock-up validated on experimental results","authors":"Matteo Hakeem Kushoro ,&nbsp;Stefano Colombi ,&nbsp;Gabriele Croci ,&nbsp;Andrea Dal Molin ,&nbsp;Erik Gallo ,&nbsp;Massimo Nocente ,&nbsp;Mikhail Osipenko ,&nbsp;Oscar Putignano ,&nbsp;Marica Rebai ,&nbsp;Davide Rigamonti ,&nbsp;Marco Tardocchi ,&nbsp;Giuseppe Gorini","doi":"10.1016/j.fusengdes.2025.114875","DOIUrl":"10.1016/j.fusengdes.2025.114875","url":null,"abstract":"<div><div>The Silicon Carbide (SiC) Solid State Detector (SSD) is an interesting alternative to diamond detector for fast neutron detection and spectroscopy. Despite this, and unlike diamonds, SiC was never installed on a Tokamak and, thus, was never characterized on a fusion plasma emission. This work aims to predict the response of a SiC when exposed to the neutron spectrum of future Tokamak devices. This is achieved by combining the neutron spectra measured by diamonds during the DTE2 JET campaign with the experimental characterization of SiC at various neutron energies on spallation and DT sources performed in the past through the means of a Geant4 simulation. The SiC response to an ideal thermal plasma and to a neutron and gamma mixed fields are also produced.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"214 ","pages":"Article 114875"},"PeriodicalIF":1.9,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143444614","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Online monitoring of tritium in water using uncladed plastic scintillating fibers","authors":"Qun Li ,&nbsp;Shengnan Chu ,&nbsp;Chunling Wang ,&nbsp;Yulu Yan ,&nbsp;Binyuan Xia ,&nbsp;Maobing Shuai","doi":"10.1016/j.fusengdes.2025.114876","DOIUrl":"10.1016/j.fusengdes.2025.114876","url":null,"abstract":"<div><div>The present study focuses on applying uncladed plastic scintillation fiber for an online tritium monitor in water. Initially, the hydrophilicity of the fiber surface was enhanced with atmospheric pressure cold plasma, resulting in increased surface roughness and a reduction in water contact angle. Then, the uniformity of liquid flow within the fiber array was examined using the COMSOL simulation software while varying fiber spacing. A fiber spacing of 0.5 mm was found to be adequate for achieving uniformity of liquid flow. Finally, three types of flow cells were prepared based on differences in surface hydrophilicity and space between fibers, and these flow cells were used to assess online measurement performance for tritium in water. The results demonstrated that optimizing the surface hydrophilicity of the fibers contributed to an increase in count rate and reduced response time within the flow cell while adjusting the space between fibers improved the uniformity of liquid flow. The optimized flow cell yielded a radiation background count of approximately 400 cpm, an effective measurement volume of 100 mL, a detection efficiency of about 0.0139 %, and the minimum detection limit reached 16 Bq/mL when the measurement duration was 1 h (as the tritium water flow stabilized). These findings indicated that the system can monitor tritium online in nuclear wastewater and, importantly, has the potential to become a practical detection tool with further optimization. Moreover, the experiment provided valuable data on the count rate and energy spectrum during the flow of the scintillation fiber flow cell—from the inflow of tritium water to stabilization, through the evacuation of tritium water, to the rinsing with pure water. The analysis and interpretation of these data offered insights for developing and optimizing similar instruments in the future.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"213 ","pages":"Article 114876"},"PeriodicalIF":1.9,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143429250","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}

{"title":"The effect of low-angle grain boundary with extrinsic dislocation on hydrogen retention and transportation in Tungsten","authors":"Bang An ,&nbsp;Yingchong Xu ,&nbsp;Hongxian Xie","doi":"10.1016/j.fusengdes.2025.114866","DOIUrl":"10.1016/j.fusengdes.2025.114866","url":null,"abstract":"<div><div>Hydrogen (H) retention and transportation are two critical issues relating to the safe operation of future fusion reactors, and the crystal defects play key roles in the two issues. In the present work the effect of low-angle grain boundary with extrinsic dislocation on H retention and transport in tungsten was investigated using molecular dynamics method. The stress fields of low-angle grain boundary with extrinsic dislocation can be deemed as superposition of the stress field of a disclination dipole and that of the dislocations, resulting in long-range stress field around the low-angle grain boundary. Interaction energy map of H reveals that the dislocation at the negative disclination core can serve as the most efficient trapping site for H among all the dislocations, which is further confirmed by dynamic simulation. Finally, H transportation capability of the low-angle grain boundary was studied by calculation of diffusion coefficients and energy barriers of H along dislocation lines, it is found that the dislocation at the negative disclination core is also an efficient nanochannel for H transportation. The present work provided us a deep insight into H retention and transport in tungsten.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"213 ","pages":"Article 114866"},"PeriodicalIF":1.9,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143429251","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}

{"title":"Neutral Beam Injection for a tokamak-based Volumetric Neutron Source","authors":"C. Hopf ,&nbsp;C. Bachmann ,&nbsp;T. Fellinger ,&nbsp;T. Franke ,&nbsp;C. Gliss ,&nbsp;T. Härtl ,&nbsp;B. Heinemann ,&nbsp;G. Orozco","doi":"10.1016/j.fusengdes.2025.114870","DOIUrl":"10.1016/j.fusengdes.2025.114870","url":null,"abstract":"<div><div>Neutral Beam Injection (NBI) is an essential system of the Volumetric Neutron Source (VNS) currently studied by EURO<em>fusion</em>. The VNS is a medium-sized tokamak with a tritium plasma. Approximately 42 MW deuterium NBI provides heating, non-inductive current drive and fast ions for beam–target dominated fusion. The mission of the VNS is to test and qualify components such as breeding blankets in reactor-relevant conditions and exposure to high fluences of 14 MeV neutrons in continuous operation. Consistent with the size of the tokamak, the beam energy is around 120 keV, which can be achieved with the well-established technology of positive-ion-based NBI. However, no previously built NBI has been designed for continuous operation and in an environment with reactor-like neutron radiation, leading to numerous design challenges. The evolving conceptual design is based on ASDEX Upgrade’s well tested and reliable NBI injectors. Each injector beamline will have four beams from four individual sources that together provide <span><math><mrow><mo>∼</mo><mn>14</mn><mspace></mspace><mi>MW</mi></mrow></math></span> NBI. Three injectors are foreseen to operate simultaneously while the cryo pumps in a fourth injector regenerate. All beamlets of each of the four beams intersect between the toroidal field magnets at the midplane, maximising transmission and limiting the duct cross section. The remote handling concept foresees that an entire injector box is removed from the torus on rails and replaced by a spare. Repair and maintenance is then carried out in an active maintenance facility (AMF) to keep VNS down-times short. Ion source high-voltage conditioning uses a calorimeter at the AMF, eliminating the need for a calorimeter in each injector box. The paper reviews the current state of the NBI concept with an emphasis on solutions to the challenges arising from continuous operation; space limitations, beamline length and reionisation; operation in a nuclear environment and remote handling.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"213 ","pages":"Article 114870"},"PeriodicalIF":1.9,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143436915","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}