{"title":"Thermal-hydraulic analysis of the cool-down for the CFETR TF coil using the 4C code","authors":"Xinghao Wen , Roberto Bonifetto , Junjun Li , Roberto Zanino , Yu Wu","doi":"10.1016/j.fusengdes.2025.114988","DOIUrl":"10.1016/j.fusengdes.2025.114988","url":null,"abstract":"<div><div>The China Fusion Engineering Test Reactor (CFETR) will be a superconducting tokamak featuring sixteen toroidal field (TF) coils; a full-size TF coil, based on a national scientific research project, has been designed and is currently being built. The first cool-down test of the TF coil is foreseen to take place in 2025. During the entire cool-down process, it is necessary to ensure that the temperature difference between any two positions of the TF coil is <50 K to avoid irreversible damage to the coil caused by excessive thermal stress. However, the maximum temperature (<em>T</em><sub>max</sub>) within the TF coil cannot be directly and accurately obtained through experimental measurements; therefore, the thermal hydraulic analysis is crucial to prepare the cool-down strategy of the coil. In this paper, the first cool-down analysis of one CFETR TF coil is completed using the 4C code. The code is based on a 1D model of the helium flow inside the cable-in-conduit conductors coupled to a set of 2D cross sections of the steel structures, where the heat conduction is modeled. The thermal coupling between the turns and the pancakes, as well as the coupling between winding and casing, is also considered. The maximum temperature evolution within the magnet is computed and the optimized cool-down strategy (inlet temperature, inlet and outlet pressure evolution) is proposed.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"216 ","pages":"Article 114988"},"PeriodicalIF":1.9,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143826049","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}
Habib Ur Rahman , Abid Hussain , Muhammad Ilyas , Manzoor Ahmed , Haseeb ur Rehman
{"title":"A multi-domain physics-informed neural network for transient thermal analysis of a Tokamak divertor","authors":"Habib Ur Rahman , Abid Hussain , Muhammad Ilyas , Manzoor Ahmed , Haseeb ur Rehman","doi":"10.1016/j.fusengdes.2025.115036","DOIUrl":"10.1016/j.fusengdes.2025.115036","url":null,"abstract":"<div><div>In this study, a Multi-Domain Physics-Informed Neural Network (MD-PINN) framework is implemented to model a multi-layer transient heat conduction problem with complex boundary conditions in an upgraded mockup of the Pakistan Spherical Tokamak divertor configuration. Automatic differentiation is employed to compute the spatial and temporal derivatives of the temperature field, which are essential for enforcing the residuals of the governing equations, initial conditions, boundary conditions, and interface conditions in the loss function. This approach rigorously embeds the physical constraints of the problem into the neural network’s training process. The model is validated against analytical solutions for one-dimensional and two-dimensional heat conduction problems, demonstrating strong agreement. It is then applied to predict transient temperature distributions in a two-dimensional graphite divertor mockup, with results closely matching the reference solutions. While the approach effectively captures the underlying physics, the hyperparameter tuning and training phase requires significant computational time. However, once trained, the model enables near-instantaneous predictions, making it well-suited for real-time feedback applications in plasma-facing components. This study paves the way for future extensions toward an autonomous, artificial intelligence-driven simulation tool for complex, coupled multi-physics problems involving three-dimensional geometries and nonlinear materials.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"216 ","pages":"Article 115036"},"PeriodicalIF":1.9,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143825321","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":"Characterization of Pd/k medium for TCAP using van Deemter equation","authors":"J.R. Hanby , S. Silliman , W.T. Shmayda","doi":"10.1016/j.fusengdes.2025.115001","DOIUrl":"10.1016/j.fusengdes.2025.115001","url":null,"abstract":"<div><div>TCAP, or thermal cycling absorption process, is a method for separating hydrogen isotopes using the selective absorption properties of a medium, such as palladium. In order to characterize the efficiency of the medium, we performed pulse tests of deuterium into a flow of hydrogen over the range of superficial velocities from 0.5 to <span><math><mrow><mn>7</mn><mi>c</mi><mi>m</mi><mo>/</mo><mi>s</mi></mrow></math></span> and used the responses to generate van Deemter curves for four temperatures; <span><math><mrow><mn>77</mn><mi>K</mi></mrow></math></span>, <span><math><mrow><mn>195</mn><mi>K</mi></mrow></math></span>, <span><math><mrow><mn>295</mn><mi>K</mi></mrow></math></span>, and <span><math><mrow><mn>373</mn><mi>K</mi></mrow></math></span>. We found that the <span><math><mrow><mn>77</mn><mi>K</mi></mrow></math></span> runs exhibited the shortest Height Equivalent to a Theoretical Plate (HETP) values while at <span><math><mrow><mn>373</mn><mi>K</mi></mrow></math></span> the HETP values were longer by a factor of around 3.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"216 ","pages":"Article 115001"},"PeriodicalIF":1.9,"publicationDate":"2025-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143821361","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":"Gas release kinetics from neutron irradiated Li2TiO3 samples","authors":"Saulet Askerbekov , Magzhan Aitkulov , Asset Shaimerdenov , Timur Kulsartov , Assyl Akhanov , Zhanar Bugybay , Darkhan Sairanbayev","doi":"10.1016/j.fusengdes.2025.115060","DOIUrl":"10.1016/j.fusengdes.2025.115060","url":null,"abstract":"<div><div>This study investigates the kinetics of residual tritium release from neutron-irradiated samples of Li-6 enriched lithium metatitanate (Li<sub>2</sub>TiO<sub>3</sub>) using the thermal desorption spectroscopy (TDS) method. The samples were subjected to low-temperature neutron irradiation in the peripheral channel of the WWR-K reactor (Almaty, Kazakhstan) for 21 days. The accumulated thermal neutron fluence was 3.0 × 10<sup>–19</sup> см<sup>-2</sup>. During the experiments, the samples were linearly heated from room temperature to 1173 K at different heating rates. The released gaseous products were recorded using an RGA-100 mass spectrometer under deep vacuum conditions.</div><div>The experimental results revealed two distinct peaks of tritium release, corresponding to different retention mechanisms:<ul><li><span>•</span><span><div>The first peak (630–707 K) has a low activation energy (56 kJ/mol) and a small pre-exponential factor (7 c<sup>-1</sup>), indicating desorption of tritium from the surface and from the open porosity.</div></span></li><li><span>•</span><span><div>The second peak (713–794 K) is characterized by a higher activation energy (74 kJ/mol) and an increased pre-exponential factor (31 c<sup>-1</sup>), indicating the release of tritium from the closed porosity and near-surface layers.</div></span></li></ul>It was established that tritium is predominantly released in the form of HT. Thus, the obtained data enable both qualitative and quantitative characterization of the kinetic parameters of tritium release from Li<sub>2</sub>TiO, which can be useful for the selection and optimization of breeder materials for fusion reactors.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"216 ","pages":"Article 115060"},"PeriodicalIF":1.9,"publicationDate":"2025-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143821359","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}
Byung Su Lim , Keeman Kim , Hyun Wook Kim , Hyunjung Lee , Myounghun Kim , Jeongjeung Dang , Yong Chu
{"title":"Overcoming the challenges of the Future K-DEMO Superconductor Test Facility","authors":"Byung Su Lim , Keeman Kim , Hyun Wook Kim , Hyunjung Lee , Myounghun Kim , Jeongjeung Dang , Yong Chu","doi":"10.1016/j.fusengdes.2025.115023","DOIUrl":"10.1016/j.fusengdes.2025.115023","url":null,"abstract":"<div><div>The test facility for high-field superconducting conductor is currently in development in Korea with the main purpose of generating an external magnetic field of up to 16 T (Tesla). This test facility will be mainly used to test superconductors intended for K-DEMO, the next-generation fusion reactor in Korea. Achieving a magnetic field intensity of up to 16 Tesla with low-temperature superconducting materials, such as Nb<sub>3</sub>Sn, presents a significant engineering challenge. Additionally, a substantial increase in the overall costs for material and fabrication of coils has been shown. Consequently, extensive efforts have been made to address the various engineering challenges and the financial constraints. At present, the project is in the conceptual design phase to navigate through the various restrictions. Various design studies are actively progressing to generate the target magnetic field of 16 Tesla. This paper will discuss the current progress and provide the most recent technical updates concerning the construction of the future superconductor test facility.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"216 ","pages":"Article 115023"},"PeriodicalIF":1.9,"publicationDate":"2025-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143821360","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}
Michael Rott, Claus-Peter Käsemann, Oliver Seibold-Benjak, ASDEX Upgrade Team
{"title":"Replacement and enhancement of power electronics at the flywheel machine EZ2","authors":"Michael Rott, Claus-Peter Käsemann, Oliver Seibold-Benjak, ASDEX Upgrade Team","doi":"10.1016/j.fusengdes.2025.115054","DOIUrl":"10.1016/j.fusengdes.2025.115054","url":null,"abstract":"<div><div>The flywheel generator “Energiezentrale 2″ (EZ2), consisting of motor, flywheel, generator and auxiliary generator, aged 50 years, supplies ASDEX Upgrades copper Toroidal Field coils with DC current of up to 80 kA. Since there is no redundancy for this machine, a high availability has to be ensured. Therefore, during the 2023/24 experimental brake the inverter was replaced, that supplies the rotor of the 5.7 MVA doubly fed induction drive motor that accelerates the 223 t flywheel of EZ2. For starting the machine, a liquid rheostat is connected to the rotor. This resistor is also used for braking the machine. The inverter of 2 MVA is able to control the speed of the machine in the operating range between 1275 and 1650 rpm.</div><div>In addition, the rectifier has been replaced that supplies the excitation of the high current pulse power synchronous generator. By this excitation the voltage at the stator clamps is controlled that ramps up the DC current in the toroidal field coils of ASDEX Upgrade by the help of diode rectifiers. The main objectives of the excitation controller are a fast rise and a constant DC current to get a useful toroidal field during a plasma pulse. Also auxiliary rectifiers have been replaced, as two 400 A rectifiers heating the slip rings of the synchronous machine in order to reduce high abrasion, a rectifier for compensation of the remanence field of the machine resulting in a high idling current and the excitation inverter feeding the auxiliary generator that supplies DC emergency oil pumps.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"216 ","pages":""},"PeriodicalIF":1.9,"publicationDate":"2025-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143823408","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":"Fatigue and ratcheting behaviour of CuCrZr alloy under asymmetric cyclic load at high temperature","authors":"Rui Zhang , Jian Peng , Jiacheng Gu , Tianci Xue , Qian Zhang , Xueru Zhu","doi":"10.1016/j.fusengdes.2025.115044","DOIUrl":"10.1016/j.fusengdes.2025.115044","url":null,"abstract":"<div><div>CuCrZr alloy often operates at high temperature and cyclic loading conditions, and its high temperature fatigue behaviour is of great significance for ensuring the service safety of copper alloy equipment. In this paper, the influences of temperature and stress amplitude on the interaction between ratcheting and fatigue of CuCrZr at high temperature is studied through asymmetric cyclic engineering stress-controlled fatigue experiments. It is found that there are two competing failure modes in CuCrZr, namely, ductile failure caused by ratcheting strain under high-stress cyclic loading and crack propagation failure caused by fatigue damage under low-stress cyclic loading. With the increase of cyclic stress amplitude and temperature, the failure mechanism of CuCrZr changes from fatigue crack propagation failure to ratcheting ductile failure, revealing the critical transformation temperature and transformation fatigue load. Finally, the stress-based and energy-based fatigue life prediction models are established for CuCrZr alloy at high temperatures, which are verified by experimental data. This study provides the fatigue and ratcheting property data for the application of CuCrZr in the high temperature fatigue conditions, to support the structural integrity of copper alloy equipment at high temperature.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"216 ","pages":""},"PeriodicalIF":1.9,"publicationDate":"2025-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143823409","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}
V. Weinzettl , S. Vartanian , R. Dejarnac , M. Jerab , A. Havranek , F. Jaulmes , M. Dimitrova , D. Naydenkova , COMPASS team
{"title":"First partial pressure measurements using Optical Penning Gauge at the COMPASS tokamak","authors":"V. Weinzettl , S. Vartanian , R. Dejarnac , M. Jerab , A. Havranek , F. Jaulmes , M. Dimitrova , D. Naydenkova , COMPASS team","doi":"10.1016/j.fusengdes.2025.115033","DOIUrl":"10.1016/j.fusengdes.2025.115033","url":null,"abstract":"<div><div>The Optical Penning Gauge for partial pressure measurements has been successfully implemented in the lower high-field side diagnostic port of the COMPASS tokamak, demonstrating a cost-effective way for resolving deuterium and helium and enabling measurements on timescales of about ten milliseconds. The procedure of its implementation is described in detail. Calibration data for deuterium and helium are discussed, including the effect of deuterium pressure on the helium channel. Time-resolved measurements of the working gas (deuterium) and the main gaseous impurity (helium) show, how helium, used for glow discharge conditioning and typically amounting to 5 - 10 % in the shots, is released from the surface of the tokamak vacuum vessel and the plasma-facing components during the subsequent shot. Behavior of both gases in L-mode, ELM-free and ELMy H-mode regimes and even just after the main (high-current high-temperature) discharge is exemplified. Surprisingly long low-current after-discharges (2 - 3 kA, about 100 ms), predominantly in helium, were observed with the Optical Penning Gauge and confirmed with other diagnostics. Simulations of the breakdown and burn-through phase for COMPASS using the DYON code are introduced, showing reasonable agreement with the measured data.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"216 ","pages":""},"PeriodicalIF":1.9,"publicationDate":"2025-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143823401","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}
I. Pagani , F. Lucca , G. Mariani , S. Iglesias , F. Penzel
{"title":"Electromagnetic analysis on ITER first wall samples diagnostic with sub-modelling technique","authors":"I. Pagani , F. Lucca , G. Mariani , S. Iglesias , F. Penzel","doi":"10.1016/j.fusengdes.2025.115058","DOIUrl":"10.1016/j.fusengdes.2025.115058","url":null,"abstract":"<div><div>The ITER First Wall Samples Diagnostic is designed to measure the erosion and fuel retention on the First Wall (FW), caused by the load of the Charge Exchange Neutral (CXN) particles.</div><div>Ensuring the structural integrity of the FW under extreme conditions is vital for the ITER Tokamak's performance, particularly during Major Disruptions (MD) and Vertical Disruption Events (VDE), which generate intense mechanical and electromagnetic stresses. To address these challenges, a comprehensive electromagnetic (EM) analysis was conducted using advanced Finite Element (FE) modeling techniques.</div><div>A key aspect of this study was the application of a sub-modelling technique that enabled precise calculation of EM loads on individual FWS components. By focusing on specific regions of interest, the sub-modelling approach provided more detailed insights into the forces and moments generated by Lorentz forces and the impact of halo currents during plasma disruptions. This method transferred electromagnetic data from a global model to localized sub-models, ensuring accurate load predictions while reducing computational complexity.</div><div>The results demonstrate that the sub-modelling approach accurately predicts the total forces and moments acting on the FW samples, particularly identifying radial forces and torques as the dominant stress factors. The analysis revealed that the sample adapter component experiences over 90 % of the total load. These findings are instrumental in guiding the design and improving the reliability of FWS diagnostics, ensuring their functionality and durability under ITER's extreme operating conditions.</div><div>This study highlights the effectiveness of integrating global and sub-modelling techniques for assessing complex loading scenarios, contributing to the optimization of ITER's diagnostic components.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"216 ","pages":"Article 115058"},"PeriodicalIF":1.9,"publicationDate":"2025-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143815356","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}
Valerio Tomarchio , Francesca Cau , José Lorenzo , María Mercedes Parody Guzmán , Damien Furfaro , Christine Hoa , Jacek Kosek , Qiu Lilong , Junjun Li , Alexandre Louzguiti , Thierry Schild , Ana Veleiro
{"title":"Thermal structural analyses during cool down of the ITER toroidal field coil in the magnet cold test bench","authors":"Valerio Tomarchio , Francesca Cau , José Lorenzo , María Mercedes Parody Guzmán , Damien Furfaro , Christine Hoa , Jacek Kosek , Qiu Lilong , Junjun Li , Alexandre Louzguiti , Thierry Schild , Ana Veleiro","doi":"10.1016/j.fusengdes.2025.115017","DOIUrl":"10.1016/j.fusengdes.2025.115017","url":null,"abstract":"<div><div>A Magnet Cold Test Bench is being built in ITER to test some of the Toroidal Field Coils (TFC) and the Poloidal Field Coil PF1, before they will be assembled and installed in the tokamak. The purpose is to test the performance of the superconducting magnet in cryogenic conditions and with current.</div><div>The TF coil and its structures weigh about 300 tons and will be cooled down from 300 K to 4.5 K, with helium flow supplied by one of the three refrigeration cold boxes of the ITER cryogenic system, with a capacity of 25 kW at 4 K. The helium flows in the winding packs of the coil, through the bundle and central channel of the superconducting cables, and it also extracts heat through the numerous cooling pipes of the Casing.</div><div>From 300 K to 100 K, one major concern is the thermal stresses due to the different thermal contraction coefficients of the materials in the coil and its structure: superconducting cables composed of Nb<sub>3</sub>Sn and Copper strands, Stainless Steel for the conductor jacket, the radial plates and the casing, electrical insulation materials such as Glass Kapton Glass and epoxy resin.</div><div>The usual cool down process requirement is to control the temperature difference between helium outlet and inlet and to ensure that it does not exceed 50 K. For the Magnet Cold Test Bench (MCTB), a selected cool down scenario was simulated to comply with the thermal hydraulic criteria and to check the resulting thermal stresses are acceptable for the coil, insulation material, structure and supports.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"216 ","pages":"Article 115017"},"PeriodicalIF":1.9,"publicationDate":"2025-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143815355","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}