Nuclear Materials and Energy最新文献

{"title":"Development of tungsten coatings on Inconel superalloy for COMPASS upgrade plasma-facing components","authors":"Jiří Matějíček ,&nbsp;Renaud Dejarnac ,&nbsp;Cristian Ruset ,&nbsp;Eduard Grigore ,&nbsp;Ladislav Cvrček ,&nbsp;Jan Walter ,&nbsp;Frédéric Perry","doi":"10.1016/j.nme.2024.101844","DOIUrl":"10.1016/j.nme.2024.101844","url":null,"abstract":"<div><div>Thin tungsten coatings on Inconel superalloy were prepared in the frame of the COMPASS Upgrade project, the new high magnetic field tokamak with metallic walls now under construction at the Institute of Plasma Physics in Prague. The coatings will be used to cover the in-vessel Inconel tiles which are not in direct contact with the plasma, representing ∼75 % of the total first wall surface. This paper describes the latest developments in the coating technology by three different suppliers and presents a comprehensive comparative characterization of the different coatings (morphology, thickness, adhesion) produced by physical vapor deposition. Coatings with thicknesses in the range 7–20 µm were successfully produced and analyzed. Overall, they all show no blisters, no delamination nor other defects such as cracks, large pores, inclusions or droplets, and a good adhesion. All the coatings featured sufficient purity and homogeneity in thickness complying with COMPASS Upgrade specifications. The qualification of the coatings under high heat flux tests is presented in a companion paper.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"42 ","pages":"Article 101844"},"PeriodicalIF":2.3,"publicationDate":"2024-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143172387","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modelling of the X-point radiator configuration in DTT with SOLEDGE2D-Eirene","authors":"L. Balbinot ,&nbsp;G. Rubino ,&nbsp;I. Casiraghi ,&nbsp;G. Calabrò ,&nbsp;P. Innocente","doi":"10.1016/j.nme.2024.101835","DOIUrl":"10.1016/j.nme.2024.101835","url":null,"abstract":"<div><div>This work studied the feasibility of an X-point radiator (XPR) in the DTT single-null full-power scenario using the edge modelling code SOLEDGE2D-EIRENE. It predicts that the XPR is accessible in DTT using neon as seeding impurity; the accessibility to the configuration is compatible with the reduced model developed for ASDEX Upgrade and TCV. The formation of the X-point radiator in DTT leads to strong impurity and temperature redistribution with respect to standard detached plasmas and the formation of a cold volume with T<span><math><mrow><msub><mrow></mrow><mrow><mtext>e</mtext></mrow></msub><mo>&lt;</mo><mtext>10</mtext><mspace></mspace><mtext>e</mtext><mi>V</mi></mrow></math></span> as observed in other machines. The transition is sudden and had major consequences on pumping, neutral penetration and separatrix temperature. The operational window in impurity concentration between XPR formation and the plasma radiative collapse was estimated to be large. A strong bifurcation is observed at the XPR onset; the bifurcation allows for impurity seeding and concentration reduction after the XPR on-set even lower than in non-XPR standard detached cases.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"42 ","pages":"Article 101835"},"PeriodicalIF":2.3,"publicationDate":"2024-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143173558","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical modeling of impurity powder injection in W7-X","authors":"F. Nespoli ,&nbsp;Y. Feng ,&nbsp;G. Kawamura ,&nbsp;M. Shoji ,&nbsp;R. Lunsford ,&nbsp;D. Hathiramani ,&nbsp;J. Koopmann ,&nbsp;A. Nagy ,&nbsp;F. Effenberg ,&nbsp;N.A. Pablant ,&nbsp;C. Killer ,&nbsp;D. Zhang ,&nbsp;M. Kubkowska ,&nbsp;S. Jablonski ,&nbsp;G. Kocsis ,&nbsp;B. Buttenschön ,&nbsp;D. Nicolai ,&nbsp;W7-X team","doi":"10.1016/j.nme.2024.101837","DOIUrl":"10.1016/j.nme.2024.101837","url":null,"abstract":"<div><div>In this work, we present numerical simulation results of powder injection in W7-X using the EMC3-EIRENE and DIS codes. First, we model powder injection experiments performed in W7-X with the Probe Mounted Powder Injector. The simulation results qualitatively agree with visible imaging measurements. Secondly, we perform predictive simulations to guide the installation of an Impurity Powder Dropper in W7-X, allowing to choose in between several available non-vertical ports to maximize the amount of powder penetrating into the plasma, as well as the verticality of the port, to minimize sticking of the powders in the in-vessel stainless steel guiding tube. Port AEM41 is selected as the best candidate for IPD installation. The robustness of the simulation results has been verified for different plasma densities, powder materials and sizes, powder friction coefficient and changes in the plasma flow.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"42 ","pages":"Article 101837"},"PeriodicalIF":2.3,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143173561","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Quantum electron dynamics in helium ion injection onto tungsten surfaces based on time-dependent density functional theory","authors":"Atsushi M. Ito ,&nbsp;Yuto Toda ,&nbsp;Arimichi Takayama","doi":"10.1016/j.nme.2024.101836","DOIUrl":"10.1016/j.nme.2024.101836","url":null,"abstract":"<div><div>The neutralization of an ion particle on a surface is a key issue in plasma–wall interactions. We investigated helium ion injection onto a tungsten surface using time-dependent density functional theory (TDDFT) simulations. We developed the TDDFT code QUMASUN and simulated the process of electron transfer from the surface to the He nucleus by simultaneously solving the time evolution of the electron wavefunction and the classical motion of nuclei. Our results show that the probabilities of <span><math><msup><mrow><mtext>He</mtext></mrow><mrow><mn>2</mn><mo>+</mo></mrow></msup></math></span> changing into <span><math><msup><mrow><mtext>He</mtext></mrow><mrow><mn>1</mn><mo>+</mo></mrow></msup></math></span> and <span><math><msup><mrow><mtext>He</mtext></mrow><mrow><mn>0</mn></mrow></msup></math></span> on the surface are approximately 40% and 25%, respectively. The electrons captured by <span><math><msup><mrow><mtext>He</mtext></mrow><mrow><mn>1</mn><mo>+</mo></mrow></msup></math></span> and <span><math><msup><mrow><mtext>He</mtext></mrow><mrow><mn>0</mn></mrow></msup></math></span> predominantly occupy the 2s and 2p orbitals, respectively, corresponding to the excited states. In addition, this paper reports the challenges encountered while applying TDDFT to PWI research.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"42 ","pages":"Article 101836"},"PeriodicalIF":2.3,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143172386","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A new design concept of actively cooled plasma-facing units for the divertors of fusion reactors","authors":"J.P. Gunn ,&nbsp;M. Firdaouss ,&nbsp;M. Richou ,&nbsp;Claudio Maria De Simone","doi":"10.1016/j.nme.2024.101838","DOIUrl":"10.1016/j.nme.2024.101838","url":null,"abstract":"<div><div>This paper sketches a new divertor design concept that solves most of the issues already identified with the actual ITER design, especially in what concerns transient heat loading. It resists ELM heat loads better than the present ITER design. This alternative design, consisting of tubes running approximately along the magnetic field direction, simultaneously eliminates sharp toroidal edges of tungsten monoblocks that will melt, and optical hot spots that could melt or vaporize in ITER if ELMs are present. Steady state, inter-ELM divertor surface temperatures will not be higher than in ITER for identical plasma irradiation conditions. The design is just as resilient as ITER’s with respect to critical heat flux in the cooling tubes. Knowing that simple tubes might not be appropriate for a divertor design in a fusion reactor, we also discuss the possibility of bonding conical tungsten “beads” to the cooling tubes. The expected differences between the simple tube model and the one with tungsten beads will be discussed.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"42 ","pages":"Article 101838"},"PeriodicalIF":2.3,"publicationDate":"2024-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143173384","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Net lithium deposition and dominant self-sputtering in lithium tokamak experiment-β with a liquid lithium wall","authors":"E. Jung ,&nbsp;S. Abe ,&nbsp;A. Maan ,&nbsp;J. Garcia ,&nbsp;Z. Lin ,&nbsp;D.P. Boyle ,&nbsp;R. Majeski ,&nbsp;B.E. Koel","doi":"10.1016/j.nme.2024.101839","DOIUrl":"10.1016/j.nme.2024.101839","url":null,"abstract":"<div><div>We observed enhanced net lithium deposition and lithium erosion, possibly dominated by physical sputtering of lithium by lithium-ion bombardment, on the outer plasma-facing surface in the Lithium Tokamak eXperiment-β (LTX-β) during liquid lithium wall operations. Silicon crystal samples with micro-trenches (30 μm × 30 μm × 2–7 μm deep) were exposed to hydrogen plasmas in LTX-β for solid and liquid lithium wall operations. Post-mortem analysis using X-ray photoelectron spectroscopy combined with argon ion sputtering measured net lithium deposition of 8.2 or 21 nm on the silicon crystal surface exposed for ∼ 50 repeated shots of ∼ 50-ms hydrogen plasma discharges during the liquid lithium wall operations at a vessel temperature of 475 K. Energy dispersive X-ray spectroscopy measured oxygen concentration patterns on the micro-trench floors, which were due to oxidized lithium deposition. Using the inhomogeneous oxygen concentration pattern caused by an ion-shadowing effect associated with the micro-trench’s geometric structure, we determined a polar incident ion direction of 68.4 ± 1.6° referenced to the surface normal direction. This observation was well-explained by the hypothesis that self-sputtering of Li was a dominant lithium erosion source in addition to lithium sputtering by hydrogen bombardment.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"42 ","pages":"Article 101839"},"PeriodicalIF":2.3,"publicationDate":"2024-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143173562","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Integrated modeling of boron powder injection for real-time plasma-facing component conditioning","authors":"F. Effenberg ,&nbsp;K. Schmid ,&nbsp;F. Nespoli ,&nbsp;A. Bortolon ,&nbsp;Y. Feng ,&nbsp;B.A. Grierson ,&nbsp;J.D. Lore ,&nbsp;R. Maingi ,&nbsp;D.L. Rudakov","doi":"10.1016/j.nme.2024.101832","DOIUrl":"10.1016/j.nme.2024.101832","url":null,"abstract":"<div><div>An integrated modeling framework for investigating the application of solid boron (B) powder injection for real-time surface conditioning of plasma-facing components (PFCs) in tokamak environments is presented. Utilizing the DIII-D impurity powder dropper (IPD) setup, this study simulates B powder injection scenarios ranging from milligrams to tens of milligrams per second, corresponding to boron flux rates of <span><math><mrow><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mn>20</mn></mrow></msup><mtext>–</mtext><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mn>21</mn></mrow></msup></mrow></math></span> B/s in standard L-mode conditions. The comprehensive modeling approach combines EMC3-EIRENE for simulating the deuterium plasma background and the Dust Injection Simulator (DIS) for the ablation and transport of the boron powder particles. EMC3 trace impurity fluid modeling results show substantial boron transport to the inboard lower divertor, predominantly influenced by the main ion plasma flow. The dependency on powder particle size (5–<span><math><mrow><mn>250</mn><mspace></mspace><mi>μ</mi><mi>m</mi></mrow></math></span>) was found to be insignificant for the scenario considered. The effects of erosion and redeposition were considered to reconcile the discrepancies with experimental observations, which saw substantial deposition on the outer divertor plasma-facing components. For this purpose, the WallDYN3D code was updated to include boron sources within the plasma domain and integrated into the modeling framework. The mixed-material migration modeling shows evolving boron deposition patterns, suggesting the formation of mixed B-C layers or predominantly B coverage depending on the powder mass flow rate. While the modeling outcomes at lower B injection rates tend to align with DIII-D experimental observations, the prediction of near-pure boron layers at higher rates has yet to be experimentally verified in the carbon environment of the DIII-D tokamak. The extensive reach of boron layers found in the modeling suggests the need for modeling that encompasses the entire wall geometry for more accurate experimental correlations. This integrated approach sets a precedent for analyzing and applying real-time in-situ boron coating techniques in advanced tokamak scenarios, potentially extendable to ITER.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"42 ","pages":"Article 101832"},"PeriodicalIF":2.3,"publicationDate":"2024-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143173560","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Global 3D full-scale turbulence simulations of TCV-X21 experiments with SOLEDGE3X","authors":"H. Bufferand ,&nbsp;G. Ciraolo ,&nbsp;R. Düll ,&nbsp;G. Falchetto ,&nbsp;N. Fedorczak ,&nbsp;Y. Marandet ,&nbsp;V. Quadri ,&nbsp;M. Raghunathan ,&nbsp;N. Rivals ,&nbsp;F. Schwander ,&nbsp;E. Serre ,&nbsp;S. Sureshkumar ,&nbsp;P. Tamain ,&nbsp;N. Varadarajan","doi":"10.1016/j.nme.2024.101824","DOIUrl":"10.1016/j.nme.2024.101824","url":null,"abstract":"<div><div>First principle modelling of edge plasma turbulence including neutrals and plasma recycling on the wall remains a challenge, in particular due to the long time scales necessary to simulate to reach particle balance. In this contribution, we propose a strategy to address these long time scales with the fluid code SOLEDGE, resorting to 2D reduced models for turbulence as well as 3D coarse grid simulations. The approach is applied to simulate TCV-X21 reference plasma scenario for edge turbulence modelling validation.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"41 ","pages":"Article 101824"},"PeriodicalIF":2.3,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142759410","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Improved erosion estimates for the STEP divertor","authors":"A. Kirschner ,&nbsp;S.S. Henderson ,&nbsp;S. Brezinsek ,&nbsp;J. Romazanov ,&nbsp;C. Baumann ,&nbsp;M. Kovari ,&nbsp;Ch. Linsmeier ,&nbsp;STEP Team","doi":"10.1016/j.nme.2024.101827","DOIUrl":"10.1016/j.nme.2024.101827","url":null,"abstract":"<div><div>Net tungsten erosion and deposition profiles are simulated for the outer and inner lower divertor of STEP, a spherical prototype fusion reactor targeting ∼ 2040. In this contribution, previous modelling work [1] has been extended by studying the influence of various input parameters. Main aim is to analyse the influence of several modelling improvements on the erosion/deposition characteristics at the divertor targets. This comprises the consideration of an electron density decay according to the Boltzmann relation within the sheath region as well as a certain tungsten influx to the divertor originating from main wall erosion. Also, for the inner divertor improved background plasma parameters are applied taking into account a gradient along the flux surfaces compared to formerly constant electron temperature and density and ion temperature along the flux surfaces. ERO simulations have been performed for one selected plasma case with Ar seeding, both for the outer (with peak target T_e ∼ 25 eV) and inner lower divertor (with peak target T_e ∼ 3 eV).</div><div>The simulated tungsten erosion and redeposition profiles do not significantly change for the cases studied if the Boltzmann-related decay of electron density within the sheath is considered. The assumption of tungsten within the background plasma can notably alter the overall erosion/redeposition behaviour at a background tungsten concentration of 1/10 with respect to the Ar divertor concentration. The inner divertor target plate shows net deposition everywhere, while at the outer one the net erosion zone becomes smaller and the maximum net erosion peak reduces by a factor of two. Lastly, the improved background plasma for the inner divertor has moderate effects, for instance the overall tungsten redeposition at the target plate increases from 88.7% to 94.4%.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"41 ","pages":"Article 101827"},"PeriodicalIF":2.3,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142743340","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Asymmetry in particle load on divertor tiles in different magnetic field configurations of LHD","authors":"Tsukasa Sugiyama ,&nbsp;Suguru Masuzaki ,&nbsp;Mamoru Shoji ,&nbsp;Yuki Hayashi ,&nbsp;Gen Motojima ,&nbsp;Kunihiro Ogawa ,&nbsp;Gakushi Kawamura ,&nbsp;Ryutaro Kanno ,&nbsp;Hiroaki Ohtani","doi":"10.1016/j.nme.2024.101830","DOIUrl":"10.1016/j.nme.2024.101830","url":null,"abstract":"<div><div>The asymmetry of plasma-particle load on divertor tiles at helically symmetrical positions has been investigated in the Large Helical Device (LHD). The asymmetry reverses when the toroidal magnetic field direction changes, suggesting that particle drifts cause the asymmetry. This study conducted proton orbit tracing calculations under a vacuum condition to investigate the effects of grad-<em>B</em> drift and curvature drift on the asymmetry. The calculations were performed for the major radius of the magnetic axis, <em>R</em>_ax, at 3.75 m and 3.6 m configurations. The results showed that due to the effects of grad-<em>B</em> drift and curvature drift, a similar asymmetry to the experimentally observed one appeared in the number of protons reaching the divertor tiles. The degree of asymmetry (DOA), representing the ratio of protons reaching the symmetrical divertor tiles, increased with higher proton energy and was smaller for the <em>R</em>_ax = 3.75 m configuration than the <em>R</em>_ax = 3.6 m one. An analysis of the experimental data for these magnetic field configurations revealed a consistent asymmetry between the <em>R</em>_ax = 3.75 m and the <em>R</em>_ax = 3.6 m configuration. It was also found that the asymmetry increased with higher electron temperature and was smaller in the <em>R</em>_ax = 3.75 m configuration than in the <em>R</em>_ax = 3.6 m one, which was consistent with the calculations. On the other hand, the experiments showed that the DOA saturated, which was not reproduced in the calculations.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"41 ","pages":"Article 101830"},"PeriodicalIF":2.3,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143156748","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}