Fusion Engineering and Design最新文献

{"title":"Prediction and evaluation of measurement performances of imaging diagnostics for ITER wall protection","authors":"Marie-Helene Aumeunier ,&nbsp;Alexis Juven ,&nbsp;Priyanka Jena ,&nbsp;Vincent Martin ,&nbsp;Martin Kocan","doi":"10.1016/j.fusengdes.2025.114922","DOIUrl":"10.1016/j.fusengdes.2025.114922","url":null,"abstract":"<div><div>ITER divertor and first wall protection is primarily based on infrared (IR) thermography system used to measure surface temperatures and power loads of critical machine components. This system consists of 22 lines of sight installed in the equatorial and upper ports to monitor the maximum surface area of the first wall and the divertor with sufficient accuracy to analyze the plasma-wall interaction and optimize the plasma scenarios in safe conditions. Predicting the measurements performance of all these diagnostics is essential during the design phase and in preparation for operations. Particular attention is paid to spatial coverage and resolution in order to quantify operational limits. A new calculation tool, based on a fast ray-surface interaction, has been developed to accurately assess the chamber area within the field of view and evaluate the coverage of all imaging systems of ITER. The useful spatial coverage (i.e. with spatial resolution better than 50 mm/pixel) is estimated to be 77% for the first wall, 80% for the divertor. In addition, a 2D-3D mapping algorithm is used to display the calculated data onto a 3D scene model and onto a 2D representation of the in-vessel components. Such a tool is also applied and tested on WEST experimental data and then supports the preparation of ITER operation by developing adapted tools for machine protection.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"215 ","pages":"Article 114922"},"PeriodicalIF":1.9,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143644155","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":"Proposal of a criterion to select the layout of bolometric diagnostics for robust plasma radiation reconstruction in fusion devices","authors":"Ivan Wyss ,&nbsp;Valentina D'Agostino ,&nbsp;Andrea Murari ,&nbsp;Pasquale Gaudio ,&nbsp;Michela Gelfusa ,&nbsp;Gerarda Apruzzese ,&nbsp;Riccardo Rossi","doi":"10.1016/j.fusengdes.2025.114940","DOIUrl":"10.1016/j.fusengdes.2025.114940","url":null,"abstract":"<div><div>Nuclear fusion stands out as a promising energy source, with numerous experimental reactors currently operational and larger ones in various stages of construction. As reactor dimensions increase, the precise measurement of the plasma total emitted radiation becomes increasingly crucial. This quantity not only helps in evaluating tokamak power balances but also enhances the understanding of the underlying physics in different processes. To optimize the performance of large nuclear fusion reactors, for example, various radiative scenarios have been proposed. These involve injecting gas into the plasma to induce radiation emission, thereby reducing the heat load on the reactor plasma facing components. Additionally, analysing the radiation pattern within the plasma provides valuable insights into impurity transport. A key technique for extracting information on plasma radiation is tomography reconstruction based on bolometric measurements. Addressing the resulting inverse problem, an effective approach involves utilizing maximum likelihood methods, which not only facilitates the reconstruction but also offers an estimation of the reconstruction errors. This study aims to investigate the impact of the bolometer diagnostic geometry on the reconstruction performance, a critical aspect for designing bolometers for future fusion machines. Due to limited space availability, bolometer systems present a restricted number of projections, rendering the optimization of the geometry fundamental for minimizing the sources of error. The analysis performed consists of reconstructing synthetic images in different geometries, varying angles of view and the number of lines of sight. Finally, an optimal criterion is defined to guide the selection of the geometry, ensuring robust reconstruction with minimal susceptibility to measurement errors.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"215 ","pages":"Article 114940"},"PeriodicalIF":1.9,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143644172","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":"A new inverse kinematics solution method for maintenance snake arm robots based on a grouping control strategy","authors":"Zhe Wang,&nbsp;Dean Hu,&nbsp;Detao Wan,&nbsp;Yang Li,&nbsp;Chang Liu","doi":"10.1016/j.fusengdes.2025.114942","DOIUrl":"10.1016/j.fusengdes.2025.114942","url":null,"abstract":"<div><div>Based on the difference in the drive structure, snake arm robots can be roughly divided into two categories: one adopts the redundant driving and the other with the underactuated. The large number of redundant degrees of freedom gives snake arm robots great flexibility but also increases the difficulty of solving their inverse kinematics. However, the existing inverse kinematics methods are generally not universal for the two distinct categories. Aiming at this issue, a new inverse kinematics solution method is proposed in this paper. Firstly, a flexible grouping strategy is introduced, which can divide the arm's joints into a specified number of groups, thereby accommodating the constraints of underactuated structures and different task requirements of redundant drive structures. However, the motion of joints in the same group is required to be synchronized and consistent, to align with the characteristics of underactuated structures, which also determines the uniqueness of the inverse kinematics solution. By combining this characteristic, the segment of the arm within the joint group can be simplified by using the equivalent principle, and the inverse kinematics of the group are solved through iteration. Further, a forward and backward search mechanism is established to solve the inverse kinematics of the robot. The forward process is used to accomplish the approach of joint groups to the target of the arm. The backward process utilizes the vector method to derive the pose relationship between joint groups to complete their motion coupling. Finally, a series of experiments are carried out to verify the performance of the method. The experimental results show that the method can obtain the inverse kinematics solution of the snake arm robot within the joint angle limitation and achieve a relatively high position accuracy. Even under different grouping strategies, this method also can effectively acquire the solution.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"215 ","pages":"Article 114942"},"PeriodicalIF":1.9,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143644171","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":"Gamma-ray measurements of 10B(α,pγ)13C reaction for alpha-particle diagnostics in fusion plasmas","authors":"V.G. Kiptily","doi":"10.1016/j.fusengdes.2025.114959","DOIUrl":"10.1016/j.fusengdes.2025.114959","url":null,"abstract":"<div><div>In the Joint European Torus with <em>Be</em>/W first wall, measurement of the confined fusion α-particles was based on detection of γ-rays due to the <em>⁹Be(α,nγ)¹²C</em> nuclear reaction. The same diagnostic approach was accepted in the former design of the International Thermonuclear Experimental Reactor with a <em>Be</em>-wall. However, in the present non-beryllium design with full W wall and divertor, the boron impurity could be in plasmas due to boronisation of the vessel. In this case, the <em>¹⁰B(α,pγ)¹³C</em> reaction is proposed for the α-particle diagnostics. Aiming to apply this approach in fusion devises with boron impurity, the results of in-beam studies of this reaction are presented. Excitation functions of the first three states of <em>¹³C</em> were derived from the measured γ-ray angular distributions in the α-particle energy range 1.25 – 4.2 MeV. Also, high energy resolution γ-ray spectra were exploited to infer the proton differential cross-sections using the Doppler γ-line shape analysis. The results obtained are compared with other available data. Application of the <em>¹⁰B(α,pγ)¹³C</em> reaction for diagnosing both energetic <em>⁴He</em>-ions and fusion-born α-particles is proposed.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"215 ","pages":"Article 114959"},"PeriodicalIF":1.9,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143644174","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":"Stabilizing long pulse D− extraction for NBI using a Cs shower","authors":"C. Wimmer,&nbsp;A. Döring,&nbsp;T. Fellinger,&nbsp;M. Fröschle,&nbsp;A. Heiler,&nbsp;D. Mussini,&nbsp;U. Fantz","doi":"10.1016/j.fusengdes.2025.114949","DOIUrl":"10.1016/j.fusengdes.2025.114949","url":null,"abstract":"<div><div>The Neutral Beam Injection (NBI) system of ITER is based on sources for negative hydrogen ions (H<span><math><msup><mrow></mrow><mrow><mo>−</mo></mrow></msup></math></span> &amp; D<span><math><msup><mrow></mrow><mrow><mo>−</mo></mrow></msup></math></span>). Negative ions are produced by surface conversion of plasma particles on low work function materials. Cs is steadily evaporated from an oven into the ion source for the reduction of the surface work function. The extraction of negative ions from the source plasma is accompanied by the co-extraction of electrons. In long pulses, the electron current is steadily increasing and thus limiting the source performance in particular in deuterium operation. Simulations and measurements give hints that the flux of Cs onto the plasma grid – the first grid of the extraction system and the most important conversion surface – decreases in long pulses.</div><div>In order to increase the flux of neutral Cs, a new version of a Cs shower is tested at the BATMAN Upgrade test facility. The Cs shower consists of a small tube containing a multitude of small orifices for directed evaporation of Cs very close to the convertor surface. This allowed for the first time a steady state with extremely stable performance in long deuterium pulses (1000 s, beam time limited by radiation restrictions). However, the evaporation from the Cs shower (measured by Tunable Diode Laser Absorption Spectroscopy) shows a strong vertical asymmetry. Measures for homogenizing the evaporation need to be adapted in a next step.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"215 ","pages":"Article 114949"},"PeriodicalIF":1.9,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143641724","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":"Study on T production using high-temperature gas-cooled reactor for DEMO fusion reactor − H absorption properties of Zr sphere with Ni coating","authors":"Hideaki Matsuura ,&nbsp;Hiromi Kawai ,&nbsp;Aoi Furuya ,&nbsp;Kazunari Katayama ,&nbsp;Teppei Otsuka ,&nbsp;Etsuo Ishitsuka ,&nbsp;Shigeaki Nakagawa ,&nbsp;Kenji Tobita ,&nbsp;Satoshi Konishi ,&nbsp;Youji Someya ,&nbsp;Ryoji Hiwatari ,&nbsp;Yoshiteru Sakamoto","doi":"10.1016/j.fusengdes.2025.114944","DOIUrl":"10.1016/j.fusengdes.2025.114944","url":null,"abstract":"<div><div>We have proposed tritium (T) production using a high-temperature gas-cooled reactor (HTGR) and explored its application for initial T possession in a demonstration (DEMO) fusion reactor. To maintain T containment within the Li-loading rod throughout the HTGR operation period, Ni-coated Zr spheres are considered as T absorption materials, designed to prevent an increase in internal T partial pressure and secure T retention in the Li-loading rod. This study evaluates the performance of Zr spheres by examining their hydrogen absorption properties within the HTGR environment, where oxides coexist. In addition, the apparent diffusivities and solubilities of hydrogen in Zr are studied at pressures ranging from 80 to 8000 Pa. It is shown that the coexisting oxides cause a reduction in diffusivity but has minimal impact on solubility, the pressure has no significant impact on the hydrogen absorption performance in HTGR environment at 900 °C.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"215 ","pages":"Article 114944"},"PeriodicalIF":1.9,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143644176","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":"H-Mode density limit disruption avoidance in ASDEX Upgrade, TCV and JET","authors":"B. Sieglin ,&nbsp;M. Maraschek ,&nbsp;A. Gude ,&nbsp;F. Klossek ,&nbsp;F. Felici ,&nbsp;M. Bernert ,&nbsp;O. Kudlacek ,&nbsp;A. Pau ,&nbsp;L. Piron ,&nbsp;M. Lennholm ,&nbsp;K. Kirov ,&nbsp;S. Hongjuan ,&nbsp;A. Parrott ,&nbsp;P. Fox ,&nbsp;O. Sauter ,&nbsp;C. Stuart ,&nbsp;C. Ashe ,&nbsp;A. Huber ,&nbsp;W. Treutterer ,&nbsp;ASDEX Upgrade Team ,&nbsp;TCV Team ,&nbsp;JET contributors ,&nbsp;EUROfusion WPTE Team","doi":"10.1016/j.fusengdes.2025.114961","DOIUrl":"10.1016/j.fusengdes.2025.114961","url":null,"abstract":"<div><div>In recent years a strong effort has been made to investigate disruption avoidance schemes in order to aid the development of integrated operational scenarios for ITER. Within the EUROfusion programme the disruptive H-Mode density limit (HDL) has been studied on ASDEX Upgrade, TCV and JET. This paper presents the results from these studies in the view of the plasma control system (PCS).</div><div>The successful migration of disruption avoidance schemes based on direct measurements as well as state space based HDL observers across the devices has been demonstrated. HDL disruption avoidance using continuous control is now routinely available at TCV and ASDEX Upgrade, using both observer types. Exception handling based disruption avoidance has been utilized on all three devices. All three control systems allowed the implementation of the desired schemes with minimal adaptions, implementing the equivalent detection algorithms. Using the same experimental methodology it is confirmed that the XPR/MARFE movement, which is preceding the disruptive HDL, is similar on all three devices. The main difference lies in the associated times scales which increase with machine size. This would be beneficial for large devices, such as ITER and DEMO, since it would give the control system more time to apply the appropriate disruption avoidance action. As actuator auxiliary heating, gas flow and plasma shaping have been successfully demonstrated.</div><div>This work gives input for the requirements of future tokamak control systems which should enable the necessary disruption avoidance schemes. All disruption avoidance schemes developed during the studies can be implemented in the ITER PCS with its currently foreseen capabilities.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"215 ","pages":"Article 114961"},"PeriodicalIF":1.9,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143641723","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":"Research on gas target neutralization processes for negative ion beam","authors":"Haohua Xia,&nbsp;Chen Zuo,&nbsp;Hanyang Liu,&nbsp;Ming Ding,&nbsp;Junbin Zhao","doi":"10.1016/j.fusengdes.2025.114931","DOIUrl":"10.1016/j.fusengdes.2025.114931","url":null,"abstract":"<div><div>Neutral Beam Injection (NBI) is one of the most important heating methods in magnetic confinement fusion. It needs to convert high-energy charged particles into neutral particles as efficiently as possible, and gas neutralization is currently widely used due to its simplicity and maturity. The target gas density distribution is a critical parameter for gas neutralizers, which affects the neutralization efficiency and beam transmission. This paper focuses on the processes of negative ion beam neutralization, based on a coupled simulation model of gas density distribution and beam transmission. The influence of gas injection methods and neutralizer length on the evolution of beam components were analyzed in detail. The results indicate that by maintaining the gas target thickness at the optimal value, the gas injection methods significantly affect the distribution of target gas density and the symmetry of beam particles at the beam transmission section. Increasing the length of the neutralizer can significantly decrease the required gas inlet rate, which can further reduce the vacuum system load and re-ionization of beam particles in the vacuum chambers. The influence of beam divergence on the power load distribution and transmission efficiency were also analyzed, providing references for the design of gas neutralizers in NBI systems.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"215 ","pages":"Article 114931"},"PeriodicalIF":1.9,"publicationDate":"2025-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143636631","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":"Virtual simulator for the ITER Agile Robot Transporter with an inverse kinematic algorithm considering joint limits and collision avoidance","authors":"Chang-Hwan Choi ,&nbsp;Jonas Kynde ,&nbsp;Soumik Sarkar ,&nbsp;David Hamilton ,&nbsp;Raphael Hery ,&nbsp;Jim Palmer","doi":"10.1016/j.fusengdes.2025.114927","DOIUrl":"10.1016/j.fusengdes.2025.114927","url":null,"abstract":"<div><div>Remote Handling (RH) systems are required to maintain the in-vessel components inside the ITER Vacuum Vessel (VV) because of high radiation. The Agile Robot Transporter (ART) is under development to cope with the in-vessel maintenance needs. This paper describes a virtual simulator of the Transporter to verify its kinematics such as joint ranges and body lengths whether it is suitable to carry out the blanket first wall maintenance. Independent joint control and sequential joint control algorithms are implemented, which are used to simulate the deployment sequence of the Transporter. End-effector control, null space control, automatic trajectory generation and control algorithms are implemented by using inverse kinematic algorithms, which are used to produce various postures of the Transporter to access the blanket first walls. The control algorithms consider the physical constraints such as the joint limits, internal collision avoidance among the Transporter’s bodies, and external collision avoidance between the Transporter’s bodies and the blanket first walls. The simulation results demonstrate that the Transporter can be deployed from the port into the VV and it can access all blanket first walls while respecting the physical constraints.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"215 ","pages":"Article 114927"},"PeriodicalIF":1.9,"publicationDate":"2025-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143628678","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":"Dose assessment of gaseous tritium release from deuterium-tritium fusion devices based on steady-state plume model","authors":"Weijie Cui ,&nbsp;Zaixin Li ,&nbsp;Qixiang Cao ,&nbsp;Bo Cao","doi":"10.1016/j.fusengdes.2025.114965","DOIUrl":"10.1016/j.fusengdes.2025.114965","url":null,"abstract":"<div><div>The deuterium-tritium fusion represents a promising avenue for achieving commercial controlled nuclear fusion, but the usage of radioactive tritium poses significant environmental and radiological risks to personnel. To evaluate the radiological impact on nearby staff and the public from atmospheric tritium released during the steady-state operation of fusion devices, this study developed a dose assessment code based on the steady-state Gaussian plume model. Using tritium water vapor release rates from the ITER safety report as the source term, we calculated the tritium doses absorbed via inhalation and skin contact for various age groups, utilizing 2023 ECMWF reanalysis meteorological data for an inland basin site in China, a hypothetical site in Daya Bay, and the ITER site. The results indicate that the maximum public dose near the inland basin site is 0.030 mSv/yr, near the Daya Bay site is 0.015 mSv/yr, and near the ITER site is 0.018 mSv/yr, all of which are well below the ITER project's limit of 0.1 mSv/yr. Thus, fusion devices are radiologically safe for the surrounding personnel under normal operation.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"215 ","pages":"Article 114965"},"PeriodicalIF":1.9,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143621483","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}