Nuclear Materials and Energy最新文献

{"title":"Fluctuation entrainment and SOL width broadening in small/grassy ELM regime","authors":"X.Q. Xu ,&nbsp;N.M. Li ,&nbsp;M.L. Zhao ,&nbsp;X. Liu ,&nbsp;P.H. Diamond ,&nbsp;B. Zhu ,&nbsp;T.D. Rognlien ,&nbsp;G.S. Xu","doi":"10.1016/j.nme.2025.101866","DOIUrl":"10.1016/j.nme.2025.101866","url":null,"abstract":"<div><div>This study delves into the phenomena of fluctuation within the Scrape-Off Layer (SOL) of tokamak fusion reactors, with a specific focus on its impact on SOL width, particularly during grassy Edge Localized Modes (ELMs). Employing a comprehensive approach involving analysis and simulations, including BOUT++ and UEDGE simulations, we examine the role played by the fluctuation energy flux (<span><math><msub><mi>Γ</mi><mi>ε</mi></msub></math></span>) and various control parameters in shaping the dynamics of fluctuation entrainment. Our findings shed light on the intricate process of transporting fluctuation energy from the pedestal to the SOL, a process influenced by critical factors such as fluctuation correlation length and SOL electric field shear. These insights yield valuable strategies for effectively managing SOL width and achieving plasma detachment, both of which are essential for optimizing fusion reactor performance and ensuring operational stability. Notably, the adoption of H-mode with small/grassy ELMs holds significant promise in addressing three pivotal challenges for future tokamak fusion reactors: minimizing the size of ELMs, expanding the SOL width, and aiding in the detachment of divertor plasma at lower plasma densities, all while avoiding back transitions to low confinement and disruptions.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"42 ","pages":"Article 101866"},"PeriodicalIF":2.3,"publicationDate":"2025-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143173566","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":"Corrosive behavior of structural F82H RAFM steel by LTZO ceramic breeder pebbles","authors":"Kosuke Kataoka ,&nbsp;Keisuke Mukai ,&nbsp;Juro Yagi ,&nbsp;Motoki Nakajima ,&nbsp;Jae-Hwan Kim ,&nbsp;Takashi Nozawa","doi":"10.1016/j.nme.2025.101875","DOIUrl":"10.1016/j.nme.2025.101875","url":null,"abstract":"<div><div>In this study, corrosion behavior of F82H reduced activation ferritic/martensitic steel (RAFM) by LTZO (Li₂₊<em>_x</em>TiO₃₊<em>_y</em> solid solution with 20 wt% Li₂ZrO₃) ceramic breeder pebbles was investigated at 773–998 K in an inert sweep gas condition (Ar + 0.1 % H₂). Due to vapor gas release from the breeder pebbles and those penetrations, corrosion layer formed on the surface of the F82H steel. Glow discharge optical emission spectroscopy (GD-OES) and X-ray diffraction (XRD) identified the corrosion products as cubic, spinel, and rhombohedral Li–TM–O (TM: transition element in F82H such as Fe, Cr, and Mn). The growth of the corrosion layer thickness followed a parabolic curve at 833 K, yielding apparent diffusion coefficient of <em>D</em> = 6.95 × 10^–13 cm²/s. Rapid growth was observed at 993 K after a parabolic growth which could be triggered by failure of the protective layer. A comparative analysis indicates a predominant effect of humidity and oxygen in the sweep gas on the growth rate, while the composition and shape of breeding materials have minor impacts.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"42 ","pages":"Article 101875"},"PeriodicalIF":2.3,"publicationDate":"2025-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143173094","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":"The separatrix electron density in JET, ASDEX upgrade and alcator C-Mod H-mode plasmas: A common evaluation procedure and correlation with engineering parameters","authors":"D. Silvagni ,&nbsp;O. Grover ,&nbsp;A. Stagni ,&nbsp;J.W. Hughes ,&nbsp;M.A. Miller ,&nbsp;B. Lomanowski ,&nbsp;G. Ciraolo ,&nbsp;M. Dunne ,&nbsp;T. Eich ,&nbsp;L. Frassinetti ,&nbsp;C. Giroud ,&nbsp;I. Jepu ,&nbsp;A. Kallenbach ,&nbsp;A. Kirjasuo ,&nbsp;A. Kuang ,&nbsp;T. Luda ,&nbsp;C. Perez von Thun ,&nbsp;T. Pütterich ,&nbsp;H.J. Sun ,&nbsp;H. Zohm","doi":"10.1016/j.nme.2025.101867","DOIUrl":"10.1016/j.nme.2025.101867","url":null,"abstract":"<div><div>The separatrix electron density is an important parameter for core-edge scenario integration in tokamak devices, as it influences plasma confinement, divertor detachment and disruption avoidance. This quantity has been measured in H-mode discharges on JET, ASDEX Upgrade and Alcator C-Mod by applying the same fitting function to Thomson scattering measurements, and by employing the same analysis technique based on scrape-off layer power balance. To estimate the power crossing the separatrix, the inter-ELM time derivative of the plasma energy <span><math><mrow><mi>d</mi><mi>W</mi><mo>/</mo><mi>d</mi><mi>t</mi></mrow></math></span> has been experimentally evaluated and found to be approximately a constant fraction of the absorbed heating power. Correlations between <span><math><msub><mrow><mi>n</mi></mrow><mrow><mi>e</mi><mo>,</mo><mi>sep</mi></mrow></msub></math></span> and engineering parameters have been investigated, revealing that <span><math><msub><mrow><mi>n</mi></mrow><mrow><mi>e</mi><mo>,</mo><mi>sep</mi></mrow></msub></math></span> scales with the divertor neutral pressure <span><math><msub><mrow><mi>p</mi></mrow><mrow><mn>0</mn><mo>,</mo><mi>div</mi></mrow></msub></math></span> in a similar manner across all devices. Additionally, when <span><math><msub><mrow><mi>n</mi></mrow><mrow><mi>e</mi><mo>,</mo><mi>sep</mi></mrow></msub></math></span> is normalized to the obtained <span><math><msub><mrow><mi>p</mi></mrow><mrow><mn>0</mn><mo>,</mo><mi>div</mi></mrow></msub></math></span> dependency, no clear correlation with the plasma current is found. These observations are in agreement with the 2-point model, which suggests that the upstream separatrix density is mainly set by the recycling at the divertor target.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"42 ","pages":"Article 101867"},"PeriodicalIF":2.3,"publicationDate":"2025-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143173572","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":"ERO2.0 predictions of nickel migration in the JET ITER-Like Wall","authors":"Pyry Virtanen ,&nbsp;Henri Kumpulainen ,&nbsp;Roni Mäenpää ,&nbsp;Mathias Groth ,&nbsp;Juri Romazanov ,&nbsp;Sebastijan Brezinsek ,&nbsp;JET contributors","doi":"10.1016/j.nme.2025.101864","DOIUrl":"10.1016/j.nme.2025.101864","url":null,"abstract":"<div><div>Nickel transport in the Joint European Torus with the ITER-like wall (JET-ILW) is predicted using the 3D Monte-Carlo code ERO2.0, simulating the erosion and deposition of impurities in 3D geometry and utilizing hydrogenic background plasmas generated by the 2D edge fluid code EDGE2D-EIRENE. Charge exchange fluxes are obtained from the 3D neutral Monte-Carlo code EIRENE, which are modified to account for the shielding of the vacuum vessel wall by protruding plasma facing components, such as guard limiters. ERO2.0 is used to predict Ni erosion and deposition profiles for the first three JET-ILW campaigns weighted for the plasma operation time.</div><div>The primary location of nickel erosion on the Inconel vacuum vessel wall is predicted to be on the low-field side close to the midplane. The eroded nickel is predicted to be transported onto the entrance of the high-field side divertor, due to the scrape-off layer flows, where it is predicted to deposit and to form a layer on tile 1. The peak thickness of the predicted deposit layer is of the order 1-2<span><math><mrow><mi>⋅</mi><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mn>19</mn></mrow></msup></mrow></math></span>/cm<span><math><msup><mrow></mrow><mrow><mn>2</mn></mrow></msup></math></span>, a factor of six higher than measured in post-mortem tile analysis.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"42 ","pages":"Article 101864"},"PeriodicalIF":2.3,"publicationDate":"2025-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143173088","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":"Investigation of boron powder flow rates on real-time wall","authors":"W. Xu ,&nbsp;Z. Wang ,&nbsp;Z. Sun ,&nbsp;R. Maingi ,&nbsp;Z.T. Zhou ,&nbsp;Y.H. Guan ,&nbsp;Y. Zhu ,&nbsp;X.C. Meng ,&nbsp;M. Huang ,&nbsp;Y.W. Yu ,&nbsp;G.Z. Zuo ,&nbsp;J.S. Hu","doi":"10.1016/j.nme.2025.101869","DOIUrl":"10.1016/j.nme.2025.101869","url":null,"abstract":"<div><div>The limit of boron flow rates for real-time conditioning of the first walls has been systematically investigated in the Experimental Advanced Superconducting Tokamak (EAST) with a full metal wall. Initially, solid boron injection demonstrated effective control over carbon impurities and deuterium recycling on the basis of pre-discharge boronization. A minimum flow rate, identified between 1.0 mg/s and 2.0 mg/s, was necessary for actively improving wall conditions under specific plasma operating scenarios, with this effect progressively enhancing as boron flow rates increased. Additionally, a maximum flow rate, estimated between 3.5 mg/s and 8.0 mg/s, was identified for these plasma conditions. When boron flow rates exceeded this maximum, boron-induced fueling effects influenced the plasma line-averaged density, and at excessively high flow rates, plasma disruption was observed.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"42 ","pages":"Article 101869"},"PeriodicalIF":2.3,"publicationDate":"2025-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143173091","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":"Investigation of island size effect on radiation distribution during attached and detached plasmas in the island divertor of W7-X","authors":"B.J. Peterson ,&nbsp;G. Partesotti ,&nbsp;F. Reimold ,&nbsp;G.A. Wurden ,&nbsp;Y. Gao ,&nbsp;D. Zhang ,&nbsp;V. Winters ,&nbsp;M. Kobayashi ,&nbsp;Y. Feng ,&nbsp;K. Mukai ,&nbsp;J. von Miller ,&nbsp;the W7-X Team","doi":"10.1016/j.nme.2025.101868","DOIUrl":"10.1016/j.nme.2025.101868","url":null,"abstract":"<div><div>Mitigation of heat on the first wall through divertor operation is a key to a successful future fusion reactor. W7-X employs an island divertor to control the exhaust and heat load on the plasma impacting divertor plates. Increased radiation in the divertor reduces the heat load at the plasma contact point during detachment. In this paper we investigate the distribution of the radiation using an InfraRed imaging Video Bolometer (IRVB) that views the divertor region in two dimensions giving information on both the poloidal and toroidal variation of the radiation in comparison to conventional resistive bolometer arrays that typically only give poloidal variation information. Experiments were carried out using a standard magnetic configuration modified by changing control and planar coil currents to achieve three different island sizes without changing the strike line location. For each island size low and high density (n_e = ∼4 and ∼ 7 x 10¹⁹/m³, respectively) plasmas were created with ∼ 2 MW of ECH input power, which correspond to attached and detached plasmas with radiated power fractions (f_rad) of ∼ 20–25 % and ∼ 90 %, respectively.</div><div>Results indicate an increase in density led to an increase in the IRVB radiation signals as seen in the total radiated power (and f_rad) and a slight broadening in the signals indicating less radiation from the target locations, especially the lower right location in the IRVB field of view when compared with the corresponding thermography images. However, no noticeable difference in the IRVB radiation pattern or intensity is seen with the change of the island size.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"42 ","pages":"Article 101868"},"PeriodicalIF":2.3,"publicationDate":"2025-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143173092","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":"SOLPS-ITER simulations to study the impact of aspect ratio on edge fueling neutrals in tokamaks","authors":"Yi-Cheng Chuang ,&nbsp;Saskia Mordijck ,&nbsp;Richard Fitzpatrick ,&nbsp;Richard Reksoatmodjo","doi":"10.1016/j.nme.2025.101865","DOIUrl":"10.1016/j.nme.2025.101865","url":null,"abstract":"<div><div>In this paper, we examine the role of the aspect ratio on the neutral penetration and poloidal distribution for fixed magnetic geometry and plasma profiles using SOLPS-ITER. We start from an H-mode discharge from MAST (Kirk et al., 2012), with its aspect ratio of 1.4. We shift the magnetic equilibrium and vessel in major radius to generate a new SOLPS-ITER simulation, doubling the aspect ratio to 2.8. The neutral density profile perpendicular to the magnetic flux surfaces is fitted by an exponential. We find that the opaqueness, defined as the ratio between the electron pedestal density width and the neutral penetration depth, is unaffected by changes in the aspect ratio. We observe an increase in the neutral density close to the X-point on the high field side (HFS) as the aspect ratio increases. This poloidal angle averaged 44 % increase for the aspect ratio 2.8 case compared to the MAST geometry on the lower HFS is linked to an increase in the poloidal surface-integrated particle fluxes (1/s) towards the inner divertor.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"42 ","pages":"Article 101865"},"PeriodicalIF":2.3,"publicationDate":"2025-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143173095","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":"Effect of microstructure on hydrogen absorption in WMoTaNbV high-entropy alloy","authors":"Anna Liski ,&nbsp;Marianna Kemell ,&nbsp;Tomi Vuoriheimo ,&nbsp;Ko-Kai Tseng ,&nbsp;Ting-En Shen ,&nbsp;Che-Wei Tsai ,&nbsp;Jien-Wei Yeh ,&nbsp;Kenichiro Mizohata","doi":"10.1016/j.nme.2025.101870","DOIUrl":"10.1016/j.nme.2025.101870","url":null,"abstract":"<div><div>The refractory high entropy alloy, WMoTaNbV, absorbs significant quantities of H directly from the atmosphere. The effective hydrogen absorption has been attributed to the elemental composition of the alloy as well as its highly elaborate lattice structure. In this work, we apply scanning electron microscopy and ion beam analysis tools to investigate the effect of grain size and morphology on hydrogen storage, observing a consistency between the microstructure of WMoTaNbV alloy and hydrogen absorption.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"42 ","pages":"Article 101870"},"PeriodicalIF":2.3,"publicationDate":"2025-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143173571","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":"Time dependence of fuel retention in JET be plasma-facing components – Comparison of single and multiple ITER-like wall campaigns","authors":"Y. Zayachuk ,&nbsp;N. Catarino ,&nbsp;J. Likonen ,&nbsp;M. Rubel ,&nbsp;A. Widdowson ,&nbsp;JET contributors","doi":"10.1016/j.nme.2025.101872","DOIUrl":"10.1016/j.nme.2025.101872","url":null,"abstract":"<div><div>Deuterium retention was measured in beryllium samples from the JET ITER-like wall limiter tiles that were in the JET vessel for one and three campaigns (in vessel during 2015–2016 and 2011–2016, respectively), using thermal desorption spectroscopy, ion beam analysis and secondary ion mass spectrometry. It was found that overall retention increases with time non-linearly but somewhat slower than a square root of plasma exposure time. Depth distribution of retained deuterium was observed to change with time, with near-surface content being variable and dependent on recent plasma exposure conditions, and bulk contribution progressively increasing. Desorption peaks were observed to shift to higher temperatures with time. Experimental evidence suggests that long-term deuterium accumulation in the Be limiter components in JET is diffusion-dominated, with observed changes as function of time being consistent with the correspondingly deeper diffusion due to the propagation of the diffusion front. Cleaning interventions are found to only slow down this propagation and not stop it.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"42 ","pages":"Article 101872"},"PeriodicalIF":2.3,"publicationDate":"2025-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143173565","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":"Behavior of low alloy reactor pressure boundary steels in the loading range relevant for severe accidents and implications for material modeling in FE analyses","authors":"Christoph Bläsius ,&nbsp;Jürgen Sievers ,&nbsp;Yongjian Gao ,&nbsp;Stefan Weihe","doi":"10.1016/j.nme.2025.101873","DOIUrl":"10.1016/j.nme.2025.101873","url":null,"abstract":"<div><div>This work presents a comprehensive compilation of material data and knowledge on the behavior of low alloy reactor pressure boundary steels, including SA533B1, SA508 Gr.3, 16MND5, 20<!--> <!-->MnMoNi<!--> <!-->5<!--> <!-->5, 19MnNiMo, 22<!--> <!-->NiMoCr<!--> <!-->3<!--> <!-->7, 15Kh2MFA and 15Kh2NMFA in the severe accident loading range. These data were compiled within the scope of the recently finished OECD/NEA CSNI WGIAGE/WGAMA activity on a Status Report on the RPV Integrity Assessment for In-Vessel Retention and include new results from different recent test campaigns. The data is compared and interpreted, revealing particularities in the extreme loading range, such as a relation between short-term creep and tensile deformation, as well as similarities between steel grades. Relevant factors of influence on deformation, damage and failure behavior are identified, and potential sources of scatter and uncertainties are discussed and quantified. The data confirm the assumption that loss of external cross-section is a principal mechanism of damage and failure in the relevant loading range due to the high ductility. Based on the findings, implications about material modeling in Finite Element codes are drawn and best practices are proposed. These include the choice between classical and constitutive models, the choice of deformation laws, the consideration of primary, secondary and/or tertiary creep, potential pitfalls as well as the selection of suitable failure criteria for relevant failure mechanisms.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"42 ","pages":"Article 101873"},"PeriodicalIF":2.3,"publicationDate":"2025-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143173089","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}