Nuclear Materials and Energy最新文献

{"title":"Blob velocities and sizes in the Alcator C-Mod scrape-off layer for ohmic and high confinement mode plasmas","authors":"A.D. Helgeland ,&nbsp;J.M. Losada ,&nbsp;J.L. Terry ,&nbsp;O.E. Garcia","doi":"10.1016/j.nme.2025.101930","DOIUrl":"10.1016/j.nme.2025.101930","url":null,"abstract":"<div><div>An improved time delay estimation method is used to calculate the velocity of cross-field blob motion in the scrape-off layer of Alcator C-Mod for an ohmic and two high confinement (H-mode) plasmas; an edge localized mode free and an enhanced D-alpha H-mode. The gas puff imaging data analysis results are interpreted in the framework of a stochastic model that describes the fluctuations as a super-position of uncorrelated blob-like structures. In all confinement modes investigated, the scrape-off layer is dominated by large amplitude, blob-like filaments moving radially outwards with velocities in the range from 400 to <span><math><mrow><mn>1000</mn><mspace></mspace><mspace></mspace><mi>m/s</mi></mrow></math></span>. Blobs in high confinement mode plasmas have similar velocities and sizes as in ohmic plasma, which is consistent with the close similarity of conditionally averaged burst shapes and frequency spectra for the confinement modes investigated.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"43 ","pages":"Article 101930"},"PeriodicalIF":2.3,"publicationDate":"2025-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143895607","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Long-term thermal stability of biphasic Li4SiO4-Li2TiO3 EU reference tritium breeder ceramics enriched in Li-6","authors":"Julia Leys,&nbsp;Thomas Bergfeldt,&nbsp;Oliver Leys,&nbsp;Regina Knitter","doi":"10.1016/j.nme.2025.101932","DOIUrl":"10.1016/j.nme.2025.101932","url":null,"abstract":"<div><div>The long-term thermal stability of Advanced Ceramic Breeder (ACB) pebbles was investigated in an annealing experiment at 700 and 900 °C in He + 0.1 vol% H₂ gas atmosphere for up to 60 days. Four batches of biphasic ACB pebbles, consisting of Li₄SiO₄ with additions of 30 and 35 mol% Li₂TiO₃ and different lithium-6 contents (7.6, 60 and 90<!--> <!-->at%) were selected for the experiment. Material properties such as the chemical composition, phase content, microstructure, porosity, and mechanical properties were determined after certain time intervals and at the end of the experiment. The ACB pebbles show good performance under high temperatures as no lithium loss nor secondary phases occur. Furthermore, the microstructure, porosities, and mechanical stabilities did not exhibit significant changes over time.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"43 ","pages":"Article 101932"},"PeriodicalIF":2.3,"publicationDate":"2025-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143825764","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Heterogenous microstructure and texture evolution of K-doped tungsten thick plate during hot-rolling processing","authors":"Ping Ren ,&nbsp;Qinglin Liu ,&nbsp;Jiupeng Song ,&nbsp;Binyou Yan ,&nbsp;Mengxia Liang ,&nbsp;Shaowei Dai ,&nbsp;Fan Feng ,&nbsp;Youyun Lian ,&nbsp;Jianbao Wang ,&nbsp;Xiang Liu","doi":"10.1016/j.nme.2025.101931","DOIUrl":"10.1016/j.nme.2025.101931","url":null,"abstract":"<div><div>The fabrication and processing of large bulk materials such as potassium (K)-doped tungsten pose significant technical challenges in terms of sintering and forming processes. In this study, 43 mm thick plates were prepared and hot rolled into different rolling strains. The evolution of the microstructure and texture during hot rolling was examined systematically. A heterogeneous microstructure with significant microstructural differences was observed from the edge to the core along the normal direction. Specifically, the<!--> <!-->edge was mainly composed of equiaxed fine grains, whereas the core was dominated by large pancake-shaped grains mixed with slightly elongated fine grains. This heterogeneous microstructure is attributed to the differential phenomenon, specifically dynamic recrystallization at the edge and partial dynamic recrystallization at the center. This difference arises from the strain gradient and heterogeneous distribution of K bubbles within the thick rolled plate. In addition, the dynamic recrystallization texture is predominantly influenced by the oriented nucleation effect of grains with α-fiber and γ-fiber texture components.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"43 ","pages":"Article 101931"},"PeriodicalIF":2.3,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143776879","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":"Oxidation behaviour of CVD and electroplated Al-base coatings for EUROFER97","authors":"Anastacia Wright ,&nbsp;Benedict Keates ,&nbsp;Zhexin Cui ,&nbsp;Eric Prestat ,&nbsp;Sergio Lozano-Perez ,&nbsp;Liberato Volpe","doi":"10.1016/j.nme.2025.101927","DOIUrl":"10.1016/j.nme.2025.101927","url":null,"abstract":"<div><div>The reduced activation ferritic/martensitic (RAF/M) EUROFER97 is the primary candidate for coolant-facing alloys of the European DEMO reactor. However, EUROFER97 will face harsh environment, and it might experience enhanced degradation due to the synergistic exposure to flowing high temperature water coolant, tritium embrittlement and ionising radiation. A possible solution is to use self-passivating coatings that can interact with the environment to provide corrosion and tritium permeation protection during in service operation. In this study, EUROFER97 was firstly Al-base coated using either a chemical vapour deposition (CVD at 700 °C or 750 °C) or electroplating process (room temperature); and then oxidised in a 2-step process using the same tempering (980 °C) and normalisation (760 °C) temperatures used for EUROFER97. These temperatures were used to assess their suitability for obtaining a stable and protective Al-base oxide without altering the microstructure of EUROFER97. Advanced microscopy characterizations revealed the formation of a ≈0.6 µm α-Al₂O₃ layer over an intermetallic Al-Fe-rich interdiffusion microstructure of ≈80 µm depth. However, the interdiffusion layer was highly decorated with voids that might act as stress concentrators during in-plant service, thus being detrimental to the material performance. This study compares different Al-base coating techniques and provides a preliminary insight on the selection of oxidation temperatures for EUROFER97, finding that the current 2-step oxidation process needs further optimisation before being industrialised.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"43 ","pages":"Article 101927"},"PeriodicalIF":2.3,"publicationDate":"2025-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143746396","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":"Tritium retention characteristics of the dust in LHD after the deuterium plasma experiment","authors":"Teppei Otsuka ,&nbsp;Yuya Ando ,&nbsp;Miyuki Yajima ,&nbsp;Gen Motojima ,&nbsp;Suguru Masuzaki","doi":"10.1016/j.nme.2025.101928","DOIUrl":"10.1016/j.nme.2025.101928","url":null,"abstract":"<div><div>Tritium (T) retention of the dust particles collected at ten toroidal sections of the Large Helical Device (LHD) after the 21st experimental campaign, in which deuterium (DD) plasma experiments were conducted, were evaluated by an enhanced full combustion method (EFCM), and their individual T retention was characterized by a tritium imaging plate technique (TIPT) in combination with a scanning electron microscopy (SEM-EDS). A new method of fixation and storage of the dust particles containing T, called the electroconductive Resin surface Embedding Method (eREM), was successfully demonstrated for T retention characterization of the individual dust particles.</div><div>From the EFCM results, total T retention in dust particles collected from all toroidal sections of LHD after the 21st campaign was found to be several hundred MBq. Much higher T retention was found in the flaky C dust particles at the toroidal section with the open helical divertor than in the other closed helical divertor sections. T retention in dust particles at the section of W-coated C divertor tiles was lower than at the other sections of C divertor tiles. Zr-Ti-V dust particles originating from in to vessel getter pump materials were found, and T retention in the particles was much lower than in C dust particles.</div><div>The results from TIPT in combination with SEM-EDS indicated not all the dust particles but a half of the dust particles retained T. Such the T retention characteristics of the dust particles could be attributed to T retention characteristics of the dust source resulting in the dust particles produced and transported, and the other is depth distribution of T in the individual dust particle thicker than T β-electron escaping range.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"43 ","pages":"Article 101928"},"PeriodicalIF":2.3,"publicationDate":"2025-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143768587","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":"Boronization with tungsten plasma-facing surfaces in ASDEX Upgrade","authors":"Volker Rohde,&nbsp;Martin Balden,&nbsp;Karl Krieger,&nbsp;Rudolf Neu,&nbsp;ASDEX Upgrade Team","doi":"10.1016/j.nme.2025.101923","DOIUrl":"10.1016/j.nme.2025.101923","url":null,"abstract":"<div><div>With the switch to tungsten for the ITER plasma facing components, wall conditioning techniques such as boronization are gaining new interest. As AUG uses tungsten plasma facing components as well as boronization, the present results are summarized and reviewed in this paper. In AUG it has been shown how to operate without boronization, but conditioning by B coating through a glow discharge (boronization) is now the standard start-up procedure. The properties of the amorphous boron hydride layers, produced by boronization, depend on the discharge conditions and the residual carbon content. At AUG, chemically active layers are required to getter oxygen and deuterium. After initial conditioning, further boronization is only required for some special scenarios. The lifetime of these subsequent coatings is about 20–30 discharges, after which a new coating or a boron powder injection is required to refresh the conditioning for these special scenarios. The main effect of boronization is to reduce tungsten sputtering from the main chamber limiter by reducing impurities. As the layers are chemically active, they react with air during venting, producing unstable whitish layers that are slowly vanishing. Specifically, they cannot be studied by scanning electron microscopy or ion beam analysis, because under vacuum conditions they are lost even faster. The remaining layers are long-term stable, but contain on average only 4.1 % of the boron injected during the boronizations. This remobilisation reduces the deuterium inventory in the layers to about 0.1 % of the input during the campaigns.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"43 ","pages":"Article 101923"},"PeriodicalIF":2.3,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143746397","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":"X-point radiation: From discovery to potential application in a future reactor","authors":"M. Bernert ,&nbsp;T.O.S.J. Bosman ,&nbsp;T. Lunt ,&nbsp;O. Pan ,&nbsp;B. Sieglin ,&nbsp;U. Stroth ,&nbsp;A. Kallenbach ,&nbsp;S. Wiesen ,&nbsp;M. Wischmeier ,&nbsp;G. Birkenmeier ,&nbsp;M. Cavedon ,&nbsp;B. Lipschultz ,&nbsp;C. Lowry ,&nbsp;N. Fedorczak ,&nbsp;P. Fox ,&nbsp;M. Lennholm ,&nbsp;H. Sun ,&nbsp;P. Jacquet ,&nbsp;K. Kirov ,&nbsp;N. Vianello ,&nbsp;F. Reimold","doi":"10.1016/j.nme.2025.101916","DOIUrl":"10.1016/j.nme.2025.101916","url":null,"abstract":"<div><div>Power exhaust is a crucial issue for future fusion reactors. Divertor detachment and the required power dissipation fractions of about 95% are foreseen to be achieved by impurity seeding. In a tokamak, at high seeding levels the radiation often concentrates in a small region inside the confined plasma near the X-point. In early observations the so-called X-point radiator (XPR) often led to back-transitions to L-mode or disruptions. In metal tokamaks or with higher available heating power, these regimes can be stabilized and are now established on AUG, JET, TCV, KSTAR and WEST.</div><div>The XPR is a cold, dense plasma inside the confined region in the vicinity of the X-point, that breaks the paradigm of poloidal symmetry of density and temperature on closed flux surfaces. On AUG, the poloidal extent of the XPR is a few centimeters and it is observed up to 15<!--> <span><math><mi>c</mi></math></span> <span><math><mi>m</mi></math></span> above the X-point. The long connection length in this region and the access of neutral particles from the divertor region facilitate the creation of the XPR, as predicted by an analytical model. Numerical simulations with SOLPS-ITER match the observations at AUG and TCV and allow predictions towards a power plant, where a lower impurity concentration is required to trigger an XPR. Since the XPR greatly reduces power and particle fluxes to the targets, simpler and more efficient divertor concepts, such as the compact radiative divertor, can be envisaged for future devices. A scenario with an XPR, however, comes at the cost of an increased impurity concentration and a potential reduction in confinement, which has to be further quantified.</div><div>The XPR location can be well detected by various diagnostics, enabling responsive real-time control, even through large transients like an LH transition. The active control helped to access a new regime of ELM suppression at AUG, which is now also observed at TCV and JET.</div><div>The observation of the XPR on multiple tokamaks, the demonstration of its active control, and the emergence of theoretical models that scale favourably towards fusion reactors have opened up a new phase of advanced power exhaust research.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"43 ","pages":"Article 101916"},"PeriodicalIF":2.3,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143739927","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":"Effects of alloying elements on the solubility, diffusivity, and permeability of hydrogen in TiC from first-principles calculation","authors":"Qian Wang ,&nbsp;Liang Chen ,&nbsp;Chaoping Liang","doi":"10.1016/j.nme.2025.101924","DOIUrl":"10.1016/j.nme.2025.101924","url":null,"abstract":"<div><div>First-principles calculations were utilized to explore the effects of Zr, Nb, Ta, and W on the solubility, diffusivity, and permeability of hydrogen in TiC. It is found that the trigonal site of H in TiC, which is encircled by three Ti atoms lying a {111} plane, has been identified as thermodynamically more stable. The addition of alloying elements will destroy the equilibrium distribution of the Ti-H interaction and reduce the structural stability of interstitial H. Furthermore, the solubility, diffusivity, and permeability of H in Ti₃₂C₃₂ and Ti₃₁MC₃₂ (M = Zr, Nb, Ta, and W) at finite temperatures are derived, and the results are discussed and compared with similar experiments in the literature. Drawing upon the influence of elemental alloying on H retention, we deeply understand experimental observations and provide experimentalists with a potentially valuable recommendation for controlling hydrogen permeability.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"43 ","pages":"Article 101924"},"PeriodicalIF":2.3,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143705325","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":"Oxidation behavior of pure W and W-0.5 wt% ZrC at 700 °C and 900 °C","authors":"Yongkui Wang ,&nbsp;Xiaochen Huang ,&nbsp;Changpeng Lv ,&nbsp;Zhong Wu ,&nbsp;Jinlong Ge ,&nbsp;Jianguo Ma ,&nbsp;Xueqi Zhang","doi":"10.1016/j.nme.2025.101922","DOIUrl":"10.1016/j.nme.2025.101922","url":null,"abstract":"<div><div>This study investigates the oxidative behavior of pure tungsten and a W-0.5 wt% ZrC alloy (WZC05), was examined. Both materials were fabricated via sintering and hot rolling. The alloys were exposed to air at 700 °C for 20 h and to air at 900 °C for 8 h to analyze surface morphology, oxidation resistance, and oxidation behavior of pure tungsten and WZC05. WZC05 exhibited a significantly smaller grain size than pure tungsten. At 700 °C, the “positive effect of grain size,” caused a higher oxidation rate in pure tungsten compared with that in WZC05. After air oxidation for 20 h at 700 °C, the thickness of the oxide layer on pure tungsten reached 320 μm, whereas that on WZC05 was only 202 μm. At 900 °C, the dense oxide layer was destroyed owing to the formation of volatile WO₃, resulting in similar oxidation rates for pure tungsten and WZC05. Scanning electron micrographs revealed that the oxidized tungsten materials had a layered structure.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"43 ","pages":"Article 101922"},"PeriodicalIF":2.3,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143704095","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":"Electron beam welding behavior in Eurofer subjected to the PbLi eutectic","authors":"T. Hernández ,&nbsp;M. Roldán ,&nbsp;F.J. Sánchez ,&nbsp;N. García-Rodríguez ,&nbsp;J. Patiño ,&nbsp;J. Navas ,&nbsp;E. Carella ,&nbsp;L. Serrador ,&nbsp;I. Rueda ,&nbsp;E. Abad ,&nbsp;R. San Martín","doi":"10.1016/j.nme.2025.101920","DOIUrl":"10.1016/j.nme.2025.101920","url":null,"abstract":"<div><div>The weldability of Eurofer steel and the behavior of weld beads under relevant fusion conditions are critical factors to assess for future designs, specifically in the context of the Water-Cooled Lithium Lead (WCLL) blanket concept. Here, the area corresponding to the breeder blanket will be in direct contact with the PbLi eutectic alloy, which will flow continuously at temperatures between 400 °C and 550 °C. In this study, electron beam welding was performed on 1.4 mm thick Eurofer plates. These welded samples were subsequently exposed to flowing PbLi in the CiCLo loop at CIEMAT, maintained at 450 °C for 1000 h.</div><div>Prior to corrosion testing, the microstructure of the samples was characterized to evaluate the fusion zone width, bonding coefficient, and the presence of any defects or brittle joints. Acicular delta ferrite was observed, attributed to the high temperatures during welding and rapid cooling afterward. The potential for improved corrosion resistance through normalization treatment post-welding was also assessed. Following PbLi exposure, the specimens underwent the same microstructural characterization.</div><div>The results showed a significant microstructural change in the HAZ, which caused an increase in hardness in the HAZ; this result occurred in both the as-welded and heat-treated materials. It should be noted that non-negligible amounts of lithium were found in the HAZ, which is evidence of the diffusion of lithium from the molten eutectic into the interior of the material.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"43 ","pages":"Article 101920"},"PeriodicalIF":2.3,"publicationDate":"2025-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143679241","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}