G. Messina , P. Zito , M. Manganelli , S. Valenti , L. Morici , V. Corato , A. Ferro
{"title":"Transient electrical behavior of DEMO toroidal field coils system in normal operation and fault conditions","authors":"G. Messina , P. Zito , M. Manganelli , S. Valenti , L. Morici , V. Corato , A. Ferro","doi":"10.1016/j.fusengdes.2025.114941","DOIUrl":"10.1016/j.fusengdes.2025.114941","url":null,"abstract":"<div><div>This study examines the transient electrical behavior of the DEMO Toroidal Field Coils (TFC) system under normal operation and fault conditions. The DEMO superconducting magnet system comprises a Central Solenoid, Poloidal Field coils, and d-shaped Toroidal Field Coils, the latter all connected in series. Fast Discharge Units (FDUs) are integrated to protect the system by quickly dissipating stored magnetic energy during a quench. Simulations were conducted using MATLAB/Simulink and ANSYS/Simplorer, incorporating the TFC inductance matrix, power cable connection impedances, and stray parameters of discharge resistors. The results highlight the significant voltage peaks that occur during fast discharges, which can stress the insulation of TFCs and associated components. Various fault scenarios, including ground faults and short circuits, were analyzed to determine their impact on peak transient voltages. The findings highlight the importance of a consistent quench protection system and the accurate design of the insulation level coordination to ensure the safety and reliability of superconducting magnets. The simulations showed consistent results across both platforms, validating the models used. Future work will aim to refine the models and explore additional fault scenarios to further enhance system performance and reliability. This comprehensive fault analysis provides critical insights for the design and safety of the DEMO TFC system, ensuring its reliable operation under diverse conditions.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"215 ","pages":"Article 114941"},"PeriodicalIF":1.9,"publicationDate":"2025-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143578550","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":"Breeding Blanket Remote Maintenance Concepts in EU DEMO: From vertical extraction to horizontal accommodation in cask","authors":"Gonçalo Teixeira, Alberto Vale","doi":"10.1016/j.fusengdes.2025.114902","DOIUrl":"10.1016/j.fusengdes.2025.114902","url":null,"abstract":"<div><div>During the lifetime of a magnetic confinement nuclear fusion reactor, the replacement and decommissioning of Breeding Blankets (BB) are anticipated operations that occur in the upper-level containment cell of a reactor building, such as EU DEMO. Such operations are not feasible by in-situ human interaction. Remote Handling (RH) is the leading solution in the nuclear industry for addressing these operations. The BB is a structure with approximately 13 metres in length and weights between 100 and 120 tons. The BB is assumed to be extracted vertically and transported horizontally by casks to the Active Maintenance Facility. The BB is divided into 5 different segments for maintenance purposes: 2 inboard and 3 outboard segments. Both inboard and outboard segments pose different handling and rotation challenges. Three design concepts for handling/rotating (H/R) BB segments are proposed in this study. The concepts rely on variations of the Medium Payload Manipulation Stillage (MPMS), a system responsible for securing and H/R the BB segments. The concepts are: (I) Crane Support Concept (heavily relies on a crane to perform the rotation of BB segments), (II) Lifting Platform Support Concept (only relies on the MPMS itself to perform the rotation of the BB segments), and (III) Sliding Platform Support Concept (only relies on the MPMS itself to perform the rotation of the BB segments but provides additional support and makes use of gravity to its advantage). A comparative analysis highlighting the concept’s advantages and disadvantages is presented. The analysis and conclusions presented in this paper are derived from the assessed system requirements, possible risks concerning the CAD model designs, expected sequence of operations performed by the MPMS and the dimensions of the systems depicted in the CAD models.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"215 ","pages":"Article 114902"},"PeriodicalIF":1.9,"publicationDate":"2025-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143578548","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}
Sunday C. Aduloju, Sergey Smolentsev, Paul Humrickhouse
{"title":"Transient multiphysics modeling of the electromagnetic loads on the first wall during plasma disruptions","authors":"Sunday C. Aduloju, Sergey Smolentsev, Paul Humrickhouse","doi":"10.1016/j.fusengdes.2025.114929","DOIUrl":"10.1016/j.fusengdes.2025.114929","url":null,"abstract":"<div><div>A transient three-dimensional multiphysics finite element model that relies on coupling electromagnetic and solid-mechanics modules was developed for modeling the effect of electromagnetic (EM) loads on the in-vessel components during plasma midplane disruptions. The T-Ω formulation is employed within the finite element framework to numerically solve the Maxwell's governing equations of the electromagnetic problem, for the induced current density (<span><math><mi>J</mi></math></span>), and magnetic flux density (<span><math><mi>B</mi></math></span>) on the in-vessel components. The <span><math><mrow><mi>J</mi><mo>×</mo><mi>B</mi></mrow></math></span> forces are fed into the transient large strain kinematics within solid mechanics module through a one-way coupled interface for computation of stress and displacement distributions on the first wall (FW). The effects of the continuity of the FW on <span><math><mrow><mi>J</mi><mo>×</mo><mi>B</mi></mrow></math></span> forces and consequently stress state are studied. The current densities are higher at the edges of the non-continuous FW and at the midplane of the continuous FW. The current quench produces forces that both pull away and push the non-continuous FW to the plasma while the current quench causes the continuous FW to be pushed towards the plasma only. The maximum stress on the non-continuous FW and the continuous FW are 93 MPa and 52 MPa. The factor of safety (FOS) calculated for non-continuous and continuous FWs under the EM loads are about 5 and 10 respectively. Both walls will withstand the EM loads without failure, but the continuous blanket FW has higher structural integrity for the EM loads. Preliminary studies of the EM loads on the inboard blanket are consistent with the FW results and earlier works.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"215 ","pages":"Article 114929"},"PeriodicalIF":1.9,"publicationDate":"2025-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143578549","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}
Daniel Moya Alonso , Youngmin Lee , Enric Bargalló Font , Chang Shuk Kim , Myungho Kim , Changwook Shin , Seok-Kwon Son , Mu-Young Ahn , Martín Gorriarán Vicario , Javier Leboreiro Iriarte
{"title":"A risk analysis for Helium Cooling System (HCS) of HCCP-TBS","authors":"Daniel Moya Alonso , Youngmin Lee , Enric Bargalló Font , Chang Shuk Kim , Myungho Kim , Changwook Shin , Seok-Kwon Son , Mu-Young Ahn , Martín Gorriarán Vicario , Javier Leboreiro Iriarte","doi":"10.1016/j.fusengdes.2025.114921","DOIUrl":"10.1016/j.fusengdes.2025.114921","url":null,"abstract":"<div><div>Climate change is a reality. Every day, the effects of it are visible and one of the main challenges is to achieve carbon neutrality by 2050. With this goal, one increasing technology in clean energy generation is nuclear fusion. Nuclear fusion needs unique working conditions, such as: extremely elevated temperatures, strong electromagnetic fields, and ultra-high vacuum conditions. But another challenging milestone should be taken into account: breeding tritium. Tritium quantity is naturally scarce on Earth and has to be generated, which is costly and currently very limited. One of the missions for the later stages of ITER operation is to demonstrate the feasibility of producing tritium from lithium within the vacuum vessel, making breeding blankets a key component of ITER.</div><div>Given its relevance, there are several proposals to breed tritium, from using helium or water as a coolant, or liquid types like lithium-lead (LiPb) alloy or solid types such as lithiated ceramic pebbles as breeder. One of the proposals being currently developed, is the Helium Cooled Ceramic Pebble (HCCP), where lithiated ceramic pebbles are used as breeder and helium, as coolant. HCCP is designed to test tritium breeding, recovery, and withstand reactor loads. A key function is heating removal, with the Helium Cooling System (HCS) essential for ITER's safety and availability.</div><div>This paper describes the Reliability, Availability, Maintainability and Inspectability (RAMI) analysis and preliminary risk assessment (HAZOP) performed, together with the proposed design, operation and maintenance suggestions needed to achieve the mail goal: a reliable and safe operation for HCCP-HCS.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"215 ","pages":"Article 114921"},"PeriodicalIF":1.9,"publicationDate":"2025-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143552887","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}
Antonio Iaiunese , Raffaele Albanese , Andrea Gaetano Chiariello , Pasquale Zumbolo , Raffaele Martone
{"title":"Preliminary fault analysis of EFCC system in the Divertor Tokamak Test (DTT) facility","authors":"Antonio Iaiunese , Raffaele Albanese , Andrea Gaetano Chiariello , Pasquale Zumbolo , Raffaele Martone","doi":"10.1016/j.fusengdes.2025.114915","DOIUrl":"10.1016/j.fusengdes.2025.114915","url":null,"abstract":"<div><div>Tokamaks use Error Field Correction Coils to reduce the error fields due to misalignments and assembly tolerances in the main magnetic system, with the aim of avoiding plasma instabilities. These coils may fail for various reasons, e.g., problems in insulation or power supply. This paper presents a method to evaluate the capability of correcting error fields in case of failure of one or more coils. The effectiveness is assessed in terms of the Three Mode Error Index metric. The paper shows the results obtained for the Divertor Tokamak Test facility, but the method is quite general and can be applied to any device.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"215 ","pages":"Article 114915"},"PeriodicalIF":1.9,"publicationDate":"2025-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143552888","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":"Development of transport calculation for unstructured mesh geometry in cosRMC","authors":"Zhenyu Wang, Shichang Liu, Yixue Chen","doi":"10.1016/j.fusengdes.2025.114933","DOIUrl":"10.1016/j.fusengdes.2025.114933","url":null,"abstract":"<div><div>The traditional constructive solid geometry (CSG) modeling approach fails to meet the requirements of complex geometric transport, fusion neutronics analysis, multi-physics coupling calculations, and large-scale nuclear radiation effect simulations. To tackle these challenges, this study developed unstructured mesh (UM) transport and statistical functionalities in the Monte Carlo particle transport code, cosRMC, based on the MOAB and libMesh libraries. These functionalities allow for accurate particle positioning and tracking within UM elements, and the transport process is accelerated through a neighbor element acceleration technique. The track-length estimator is then used for tally results. To verify the computational accuracy and efficiency of the UM feature, three test cases were constructed and analyzed: a box case, a fuel rod case, and a tokamak case. The computational results demonstrate that the <em>k<sub>eff</sub></em> values calculated by UM-cosRMC geometry transport function align well with those from traditional CSG and DAGMC geometries, and the UM tally results are consistent with those of UM-MCNP calculations. In terms of computational efficiency, after employing the neighbor mesh acceleration technique, the speed of UM geometry calculations improved significantly. The UM geometry calculation efficiency based on the libMesh library is higher than that based on the MOAB library, with the former taking 1.18 to 10.42 times longer than CSG geometry calculations and 0.37 to 0.96 times that of DAGMC geometry. Compared to UM-MCNP calculation efficiency, UM-cosRMC shows a distinct advantage, reducing computation time by >70 % with the same mesh. Additionally, this study analyzed the computational efficiency of UM transport based on both libraries, and the results indicate that the libMesh-based UM calculations outperform in terms of UM reading speed, memory usage, and transport computation speed.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"215 ","pages":"Article 114933"},"PeriodicalIF":1.9,"publicationDate":"2025-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143562750","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}
F.M. Castrovinci , A. Quartararo , S. Basile , G. Bongiovì , R. Burlon , P. Chiovaro , P.A. Di Maio , A. Gioè , S. Maggio , G. Mazzone , E. Tomarchio , S. Vacca , E. Vallone , J.-H. You
{"title":"Thermofluid-dynamic assessment of the dual cooling scheme EU-DEMO divertor cassette","authors":"F.M. Castrovinci , A. Quartararo , S. Basile , G. Bongiovì , R. Burlon , P. Chiovaro , P.A. Di Maio , A. Gioè , S. Maggio , G. Mazzone , E. Tomarchio , S. Vacca , E. Vallone , J.-H. You","doi":"10.1016/j.fusengdes.2025.114903","DOIUrl":"10.1016/j.fusengdes.2025.114903","url":null,"abstract":"<div><div>The EU-DEMO divertor is currently foreseen to employ a dual cooling scheme, which involves two separate cooling circuits for the Cassette Body (CB) and the Vertical Targets (VTs), provided with cooling water at distinct operating conditions. Following the EU-DEMO project Gate Review 1, the cassette design has been revised to employ a high-temperature (295-328 °C) and high-pressure (15.5 MPa) coolant for the CB cooling circuit. These design assumptions present novel challenges in achieving uniform and effective cooling of the structure, to ensure reliable operation over the intended lifetime. Furthermore, alternative materials for the VTs-supporting Target Support Bodies (TSBs), namely CuCrZr, SS 316Ti and Eurofer97, are currently being evaluated to extend the operational lifetime of these components under irradiation. The University of Palermo, in collaboration with EUROfusion and ENEA, analysed the steady-state thermal-hydraulic performance of the EU-DEMO divertor cooling circuits with an integrated conjugate heat transfer analysis campaign of the entire divertor cassette, with the twofold aim to evaluate the CB thermal performance under the revised coolant conditions and to compare the temperature distribution in the TSBs with the different materials considered. The work was carried out following a numerical approach based on the finite volume method and adopting the ANSYS CFX computational fluid-dynamic commercial code. Models, loads and boundary conditions are herewith reported and critically discussed, together with the main outcomes obtained.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"214 ","pages":"Article 114903"},"PeriodicalIF":1.9,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143552575","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":"Steady-state Superconducting Advanced Spherical Tokamak Reactor (SASTR)","authors":"Yoshio Nagayama , Takaaki Fujita","doi":"10.1016/j.fusengdes.2025.114900","DOIUrl":"10.1016/j.fusengdes.2025.114900","url":null,"abstract":"<div><div>A concept for a Steady-state Superconducting Advanced Spherical Tokamak Reactor (SASTR) with a slim-CS is proposed. This is a spherical tokamak (ST) with an internal transport barrier (ITB) and superconducting magnets. The ITB allows for sufficient bootstrap (BS) current to sustain the plasma. The feasibility of a self-sustained SASTR is investigated by using a set of plasma burning equations. We find that the toroidal magnetic field and the confinement enhancement factor are key parameters to meet the beta limit and density limit criteria, respectively. We estimate the dependence of the cost of electricity (COE) on the aspect ratio and reactor size. We present a conceptual design of a 0.8 GWe SASTR power reactor with a major radius of 4.5 m, an aspect ratio of 1.8, a toroidal field of 2.67 T generated by Nb<sub>3</sub>Sn superconducting magnets, and a plasma current of 24.5 MA driven fully by the BS current.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"214 ","pages":"Article 114900"},"PeriodicalIF":1.9,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143552667","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":"Insight into the structural integrity assessment of the European DEMO Fusion Reactor Divertor (Part I: General discussion)","authors":"M. Muscat , P. Mollicone , N. Mantel , J.H. You","doi":"10.1016/j.fusengdes.2025.114928","DOIUrl":"10.1016/j.fusengdes.2025.114928","url":null,"abstract":"<div><div>This paper gives a description of the conceptual design of the DEMO divertor highlighting its two main functions and the main loading conditions acting on it during operation. The paper stresses the importance of Design by analysis (DBA) and structural integrity assessments at the conceptual design phase. It explains why currently the predominant DBA approach taken by the DEMO divertor group within the EUROfusion consortium is the elastic approach rather than the elastoplastic approach. Background to the DBA elastic approach describing linearization of stresses through the wall thickness and to stress categorisation that allows different stress allowables to be used for a more efficient design is given. Throughout the paper, the RCC MRx code structural integrity P Type and S Type checks as applied to the DEMO divertor components are summarised and difficulties in applying the elastic design rules to the divertor model are highlighted. These difficulties range from issues of code interpretation as applied to the DEMO divertor geometry to limited availability of material properties for Eurofer97 steel (a low activation steel) which is the main material selected for the divertor. In a follow up paper (Part II: Application Examples), some of these difficulties are demonstrated by considering two stress classification lines in the model of the current DEMO divertor model.</div><div>In this paper, the phenomenon of elastic follow up is explained and DEMO divertor load cases when this has to be taken into consideration are discussed. A short explanation on Neuber's rule, which is used to calculate estimates of plastic strain and to differentiate between primary and secondary stresses for Type S checks is also given. At the end of the paper, the conclusions summarise the interpretation and issues encountered in the application of the RCC-MRx rules for a typical nuclear fusion reactor component such as the DEMO divertor design.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"214 ","pages":"Article 114928"},"PeriodicalIF":1.9,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143552576","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}
Yuyang Liu , Weiming Li , Yao Zhang , Shouxin Wang , Jiamin Zhang , Hui Lian , Bo Hong , Wenmin Zhang , Yuan Yao , Yinxian Jie , Haiqing Liu
{"title":"Development of a real-time tangential dispersion interferometer system and its first results for density feedback on EAST","authors":"Yuyang Liu , Weiming Li , Yao Zhang , Shouxin Wang , Jiamin Zhang , Hui Lian , Bo Hong , Wenmin Zhang , Yuan Yao , Yinxian Jie , Haiqing Liu","doi":"10.1016/j.fusengdes.2025.114930","DOIUrl":"10.1016/j.fusengdes.2025.114930","url":null,"abstract":"<div><div>A horizontal tangential dispersion interferometer (TDI) system has been developed for the Experimental Advanced Superconducting Tokamak (EAST) to enhance the accuracy of density feedback. This system offers several advantages, including vibration insensitivity and a reduced risk of fringe jump errors compared to far-infrared interferometers, making it more suitable for density feedback control.</div><div>The TDI system uses two horizontal windows for tangential density measurements. Experimental results demonstrate that the TDI provides stable signals and enhances overall system reliability. Statistical analysis demonstrates that the TDI data have a measurement success rate of approximately 96%. Moreover, the temporal resolution of the system, at 20 µs, meets the requirements for real-time feedback control on EAST. The system employs a modified density real-time processing system and has been evaluated for density feedback control. During density feedback control experiments, the TDI system demonstrated notable advantages and stability, making it more suitable for future high-density burning plasma devices.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"214 ","pages":"Article 114930"},"PeriodicalIF":1.9,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143552577","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}