Nuclear Materials and Energy最新文献

{"title":"Fast prediction of irradiation-induced cascade defects using denoising diffusion probabilistic model","authors":"Ruihao Liao ,&nbsp;Ke Xu ,&nbsp;Yifan Liu ,&nbsp;Zibo Gao ,&nbsp;Shuo Jin ,&nbsp;Linyun Liang ,&nbsp;Guang-Hong Lu","doi":"10.1016/j.nme.2024.101805","DOIUrl":"10.1016/j.nme.2024.101805","url":null,"abstract":"<div><div>Irradiation-induced cascade collisions produce numerous point defects within materials, which can severely deteriorate their thermo-mechanical properties and overall performance. We propose a computational scheme that combines molecular dynamic (MD) simulations with a denoising diffusion probabilistic model (DDPM) to rapidly and accurately predict the spatial coordinates of point defects at any given primary knock atom (PKA) energy, ranging from 0 to 100.0 keV. Importantly, this capability extends to PKA energies that are exclusive from the training data set, demonstrating the robustness and generalizability of the model. The proposed scheme has been thoroughly validated by several designed indicators, including the Fréchet inception distance, the number of point defects, the distance from vacancies and self-interstitial atoms (SIAs) to their respective centroids, the inter-centroid distance between the vacancies and SIAs, the probability density of clustered defect sizes, and the sub-cascade number. Compared to MD simulations, the DDPM can generate point defects at a specific PKA energy at least ten thousand times faster. By offering a rapid and reliable means to model defect distributions across various energy levels, the proposed scheme benefits the comprehension of the cascade process and provides a valuable database for both experimental investigations and large-scale simulations.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"41 ","pages":"Article 101805"},"PeriodicalIF":2.3,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142653452","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":"Utilization of D2 molecular band emission for electron density measurement","authors":"D. Nishijima ,&nbsp;M.J. Baldwin ,&nbsp;F. Chang ,&nbsp;D. Hwangbo ,&nbsp;G.R. Tynan","doi":"10.1016/j.nme.2024.101796","DOIUrl":"10.1016/j.nme.2024.101796","url":null,"abstract":"&lt;div&gt;&lt;div&gt;D&lt;sub&gt;2&lt;/sub&gt; molecular band emission observed at a wavelength range of &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;λ&lt;/mi&gt;&lt;mo&gt;∼&lt;/mo&gt;&lt;mn&gt;557&lt;/mn&gt;&lt;mo&gt;−&lt;/mo&gt;&lt;mn&gt;643&lt;/mn&gt;&lt;mspace&gt;&lt;/mspace&gt;&lt;mi&gt;nm&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; is utilized to measure electron density, &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;n&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;e&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;, in D plasmas of the PISCES-A and PISCES-RF linear plasma devices. The D&lt;sub&gt;2&lt;/sub&gt; band is divided at &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;λ&lt;/mi&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;mn&gt;593&lt;/mn&gt;&lt;mspace&gt;&lt;/mspace&gt;&lt;mi&gt;nm&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; to make an intensity ratio, D&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;2L&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; (&lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mo&gt;∼&lt;/mo&gt;&lt;mn&gt;557&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;–&lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mn&gt;593&lt;/mn&gt;&lt;mspace&gt;&lt;/mspace&gt;&lt;mi&gt;nm&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;)/D&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;2R&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; (&lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mo&gt;∼&lt;/mo&gt;&lt;mn&gt;593&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;–&lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mn&gt;643&lt;/mn&gt;&lt;mspace&gt;&lt;/mspace&gt;&lt;mi&gt;nm&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;), where D&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;2L&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; consists predominantly of the &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;g&lt;/mi&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mspace&gt;&lt;/mspace&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;3&lt;/mn&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;msubsup&gt;&lt;mrow&gt;&lt;mi&gt;Σ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;g&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;/mrow&gt;&lt;/msubsup&gt;&lt;mspace&gt;&lt;/mspace&gt;&lt;mn&gt;3&lt;/mn&gt;&lt;mi&gt;d&lt;/mi&gt;&lt;mi&gt;σ&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;, &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;h&lt;/mi&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mspace&gt;&lt;/mspace&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;3&lt;/mn&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;msubsup&gt;&lt;mrow&gt;&lt;mi&gt;Σ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;g&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;/mrow&gt;&lt;/msubsup&gt;&lt;mspace&gt;&lt;/mspace&gt;&lt;mn&gt;3&lt;/mn&gt;&lt;mi&gt;s&lt;/mi&gt;&lt;mi&gt;σ&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;, &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;i&lt;/mi&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mspace&gt;&lt;/mspace&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;3&lt;/mn&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;Π&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;g&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mspace&gt;&lt;/mspace&gt;&lt;mn&gt;3&lt;/mn&gt;&lt;mi&gt;d&lt;/mi&gt;&lt;mi&gt;π&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;, &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;j&lt;/mi&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mspace&gt;&lt;/mspace&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;3&lt;/mn&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;Δ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;g&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mspace&gt;&lt;/mspace&gt;&lt;mn&gt;3&lt;/mn&gt;&lt;mi&gt;d&lt;/mi&gt;&lt;mi&gt;δ&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; &lt;span&gt;&lt;math&gt;&lt;mo&gt;→&lt;/mo&gt;&lt;/math&gt;&lt;/span&gt; &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;c&lt;/mi&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mspace&gt;&lt;/mspace&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;3&lt;/mn&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;Π&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;u&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mspace&gt;&lt;/mspace&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;mi&gt;p&lt;/mi&gt;&lt;mi&gt;π&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; transitions, while D&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;2R&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; mainly includes the &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;d&lt;/mi&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mspace&gt;&lt;/mspace&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;3&lt;/mn&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;Π&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;u&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mspace&gt;&lt;/mspace&gt;&lt;mn&gt;3&lt;/mn&gt;&lt;mi&gt;p&lt;/mi&gt;&lt;mi&gt;π&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; &lt;span&gt;&lt;math&gt;&lt;mo&gt;→&lt;/mo&gt;&lt;/math&gt;&lt;/span&gt; &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;a&lt;/mi&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mspace&gt;&lt;/mspace&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;3&lt;/mn&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;msubsup&gt;&lt;mrow&gt;&lt;mi&gt;Σ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;g&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;/mrow&gt;&lt;/msubsup&gt;&lt;mspace&gt;&lt;/mspace&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;mi&gt;s&lt;/mi&gt;&lt;mi&gt;σ&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; Fulcher band emission. It is experimentally","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"41 ","pages":"Article 101796"},"PeriodicalIF":2.3,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142653099","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 H-mode density limit in mixed protium–deuterium plasmas at JET with ITER-like wall","authors":"A. Huber ,&nbsp;G. Sergienko ,&nbsp;M. Groth ,&nbsp;D. Keeling ,&nbsp;M. Wischmeier ,&nbsp;D. Douai ,&nbsp;E. Lerche ,&nbsp;C. Perez von Thun ,&nbsp;S. Brezinsek ,&nbsp;V. Huber ,&nbsp;A. Boboc ,&nbsp;M. Brix ,&nbsp;I.S. Carvalho ,&nbsp;A.V. Chankin ,&nbsp;E. Delabie ,&nbsp;I. Jepu ,&nbsp;V. Kachkanov ,&nbsp;V. Kiptily ,&nbsp;K. Kirov ,&nbsp;Ch. Linsmeier ,&nbsp;M. Zlobinski","doi":"10.1016/j.nme.2024.101806","DOIUrl":"10.1016/j.nme.2024.101806","url":null,"abstract":"<div><div>Analysis of comparable discharges fuelled by either deuterium or protium reveals a clear relationship between the isotope mass and the H-mode density limit. Notably, the density limit is significantly lower in protium, showing a reduction of up to 35 % compared to identical deuterium plasma conditions. Within mixed H-mode density limit (HDL) plasmas, the maximum achievable density, or H-mode density limit, decreases with increasing protium concentration, denoted as <em>c_H</em>. For instance, the highest corresponding maximum Greenwald fraction (<em>f_GW</em>) of about 1.02 was observed in the pulse with the lowest c_H value of 4.4 %. This f_GW decreases to 0.96 at <em>c_H</em> = 48 %. The average atomic mass, <span><math><mover><mrow><mi>A</mi></mrow><mrow><mo>¯</mo></mrow></mover></math></span>, of the plasma species decreases in these pulses from the value of 1.96 (<em>c_H</em> = 4.4 %) down to 1.52 (<em>c_H</em> = 48 %). Interestingly, the maximum achievable density appears to be largely unaffected by the applied power value, regardless of whether deuterium or protium is used, as well as under mixed H/D fuelling conditions.</div><div>Additionally, the measured Greenwald fractions are agreed with a heuristic model based on the SOL pressure threshold of an MHD instability, as proposed by Goldston. This comparison, especially concerning the model’s dependence on isotopic mass, shows full consistency between the measured and predicted Greenwald fractions.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"41 ","pages":"Article 101806"},"PeriodicalIF":2.3,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142653454","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":"Lyman line opacities in tokamak divertor plasmas under high-recycling and detached conditions","authors":"Ray Chandra ,&nbsp;Detlev Reiter ,&nbsp;Niels Horsten ,&nbsp;Mathias Groth","doi":"10.1016/j.nme.2024.101794","DOIUrl":"10.1016/j.nme.2024.101794","url":null,"abstract":"<div><div>Radiation transport simulations of the deuterium Lyman line series using EIRENE predict a factor of 2 increase of Balmer-<span><math><mi>α</mi></math></span> emission in the JET-ILW low confinement divertor plasmas in high-recycling and detached conditions caused by the re-absorption of Lyman-<span><math><mi>β</mi></math></span> emission. The photon tracing model in the EIRENE code is applied to SOLPS-ITER pure deuterium plasma solutions of JET-ILW to evaluate the contribution of Lyman-<span><math><mi>β</mi></math></span> capture towards the population density of D(<span><math><mrow><mi>p</mi><mo>=</mo><mn>3</mn></mrow></math></span>) and, consequently, the Balmer-<span><math><mi>α</mi></math></span> emission. The local population escape factors of Lyman-<span><math><mi>α</mi></math></span> and Lyman-<span><math><mi>β</mi></math></span> lines in the JET-ILW divertor show steep spatial gradients and indicate local regions with high opacity in high-recycling and detached conditions. The relative contribution of Lyman-<span><math><mi>β</mi></math></span> capture towards the population density of D(<span><math><mrow><mi>p</mi><mo>=</mo><mn>3</mn></mrow></math></span>) is significant in high-recycling and detached conditions. This observation is further corroborated by line-integrated calculations using Balmer-<span><math><mi>α</mi></math></span> diagnostic line-of-sights.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"41 ","pages":"Article 101794"},"PeriodicalIF":2.3,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142653453","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":"Full-torus impurity transport simulation in boron powder injection experiments in the Large Helical Device","authors":"M. Shoji ,&nbsp;G. Kawamura ,&nbsp;R. Smirnov ,&nbsp;J. Romazanov ,&nbsp;A. Kirschner ,&nbsp;Y. Tanaka ,&nbsp;S. Masuzaki ,&nbsp;T. Kawate ,&nbsp;F. Nespoli ,&nbsp;R. Lunsford ,&nbsp;E.P. Gilson ,&nbsp;S. Brezinsek ,&nbsp;N.A. Pablant","doi":"10.1016/j.nme.2024.101803","DOIUrl":"10.1016/j.nme.2024.101803","url":null,"abstract":"<div><div>The toroidal distribution of boron deposition on plasma-facing components (PFCs) in boron powder injection using an impurity power dropper (IPD) was investigated by full-torus simulation and observations in a systematic plasma density-scan experiment. The images of the ablation of dropped boron powders observed with a visible CCD camera were consistently explained by the simulations of the ablation positions of the boron powders considering the size distribution. Simulations assuming full-torus boron deposition on the PFCs did not reproduce the observed intensity profile of boron emission lines for higher plasma densities. It indicated that the density of boron deposited on PFCs installed toroidally far from the IPD was low for higher plasma densities due to the change in the ablation positions of the boron powders toward the outboard side. The experimental results verified the previous full-torus simulation of the toroidal distribution of the boron deposition in both lower and higher plasma densities.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"41 ","pages":"Article 101803"},"PeriodicalIF":2.3,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142653098","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":"Molecular dynamic simulations of displacement cascades in molybdenum and molybdenum-rhenium alloys","authors":"Xudong Wang ,&nbsp;Rongyang Qiu ,&nbsp;Yankun Dou ,&nbsp;Yangchun Chen ,&nbsp;Haipan Xiang ,&nbsp;Peng Jiang ,&nbsp;Xinfu He ,&nbsp;Wen Yang ,&nbsp;Guangdong Liu ,&nbsp;Huiqiu Deng","doi":"10.1016/j.nme.2024.101804","DOIUrl":"10.1016/j.nme.2024.101804","url":null,"abstract":"<div><div>Molybdenum-Rhenium (Mo-Re) alloys are considered core materials for advanced nuclear reactor components due to their excellent mechanical properties, machinability, and resistance to irradiation damage. However, irradiation-induced embrittlement and phase precipitation at high temperatures, along with transmutation nuclides, have hindered their broader application. To address this, we developed a Mo-Re interatomic potential using the Finnis-Sinclair formalism, facilitating molecular dynamics simulations to study primary irradiation damage. Systemically primary irradiation damage simulations for Mo and Mo-Re alloys have been performed. It’s found that there were more Frenkel-pair defects produced during the stage of thermal spike in Mo-Re alloys but fewer defects survived at the end of the cascade compared to Mo. In addition, the number of large-size interstitial clusters and dislocation loops was higher in Mo-Re alloys than in pure Mo with the same PKA energy. This is mainly attributed to the fact that Mo-Re alloys have lower thermal conductivity, while the binding energies of interstitial clusters and dislocation loops with sizes less than 100 in Mo-Re alloys are comparable to those of pure Mo, resulting in higher defect composites and larger defect sizes in Mo-Re alloys. These findings provide valuable insights into the primary damage mechanisms in Mo-Re alloys under irradiation, offering a foundation for developing kinetic models to simulate radiation-induced microstructural evolution.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"41 ","pages":"Article 101804"},"PeriodicalIF":2.3,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142593475","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 spatial distribution characteristics of emission intensity in detachment on the divertor simulator TPDsheet-ICR","authors":"A. Tonegawa ,&nbsp;N. Okada ,&nbsp;K. Miura ,&nbsp;H. Natsume ,&nbsp;K.N. Sato ,&nbsp;K. Hoshino ,&nbsp;Y. Hayashi ,&nbsp;S. Masuzaki ,&nbsp;S. Yamoto","doi":"10.1016/j.nme.2024.101802","DOIUrl":"10.1016/j.nme.2024.101802","url":null,"abstract":"<div><div>For the first time, we have revealed the spatial structure of a detached plasma with electron–ion recombination (EIR) and molecular-activated recombination (MAR) in response to changes in ion temperature (T_i) and gas pressure. This was achieved using high-density sheet plasma generated by a linear divertor simulator (TPDsheet-ICR). The parallel-plate electrodes were positioned above and below the sheet plasma (∼10¹⁹ m⁻³). We varied the T_i from 3 to 7 eV using ion cyclotron resonance heating and investigated the parameters of the detached plasma near the target in the divergent field region. Plasma emission intensities at Balmer series (H_α and H_γ) and Fulcher band wavelengths (610 ± 10 nm) were measured with a high-speed camera equipped with an Arbaa prism. Additionally, a Langmuir probe measured the electron density and temperature of the plasma. Our results show that as the T_i increases, EIR generated near the plasma periphery disappears, while MAR gradually forms near the plasma center during the transition from detached to attached plasma. This transition occurs because the increase in T_i in the detached plasma transfers energy from ions to electrons, raising the high-energy component of the electrons, resulting in EIR disappearance and the onset of MAR.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"41 ","pages":"Article 101802"},"PeriodicalIF":2.3,"publicationDate":"2024-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142593474","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":"Systematic study of displacement threshold and the near-threshold primary radiation damage model","authors":"Shuyi Chen,&nbsp;Shengli Chen","doi":"10.1016/j.nme.2024.101800","DOIUrl":"10.1016/j.nme.2024.101800","url":null,"abstract":"<div><div>Radiation damage is a critical concern for materials employed in radiation environments such as space, radiotherapy centers, and nuclear energy systems. Numerous models have been developed to estimate the primary radiation damage. The slightly modified Athermal Recombination-Corrected (mARC)-Displacement per Atom (DPA) model proposes a simple function to describe the atomic displacement near the Threshold Displacement Energy (TDE). The present work systematically investigates the global minimum TDE and the near-TDE mARC-DPA model against experimental electron irradiation damage data for 26 materials. The determined high-accuracy global minimum TDE values are generally consistent with previous studies. The corresponding theoretical calculations agree well with experimental measurements, implying the applicability of the mARC model. Renormalization of certain experimental data is required due to the potential issues related to experimental measurements, the value of resistivity change per Frenkel pair (<span><math><mrow><msub><mi>ρ</mi><mrow><mi>F</mi><mi>P</mi></mrow></msub></mrow></math></span>), or average TDE (<span><math><mrow><msub><mi>E</mi><mi>d</mi></msub></mrow></math></span>). Nevertheless, while some experimental data are supposed to be adjusted, the analysis shows that the ratio of <span><math><mrow><msub><mi>ρ</mi><mrow><mi>F</mi><mi>P</mi></mrow></msub><mo>/</mo><msub><mi>E</mi><mi>d</mi></msub></mrow></math></span> can be definitively determined if assuming the experimental data for the remainders.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"41 ","pages":"Article 101800"},"PeriodicalIF":2.3,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142578486","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":"Strength prediction and optimization for microwave sintering of large-dimension lithium hydride ceramics: GA-BP-ANN modeling","authors":"Hongzhou Yan ,&nbsp;Huayan Chen ,&nbsp;Wenyan Zhang ,&nbsp;Maobing Shuai ,&nbsp;Bin Huang","doi":"10.1016/j.nme.2024.101801","DOIUrl":"10.1016/j.nme.2024.101801","url":null,"abstract":"<div><div>Failure typically occurs during sintering due to high thermal stress and poor strength of LiH ceramics. The short sintering time has shown to be beneficial in preventing excessive grain growth and improving ceramic performance. In this study, we built a genetic algorithm back propagation artificial neural network (GA-BP-ANN) model to predict the strength margins under different work conditions. Sensitivity analysis showed that the thickness and end control time were the most relevant parameters for strength margins, and the GA-BP-ANN model demonstrated the most efficient sintering work condition for a given thickness. Through statistical analysis of the strength margin predicted by the GA-BP-ANN model, we found that the bilinear temperature control method expanded the range of safe sintering conditions by 30% compared to the linear temperature control method. The research results of this study may serve as a reference for the safe and efficient sintering of LiH ceramics.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"41 ","pages":"Article 101801"},"PeriodicalIF":2.3,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142593473","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":"In search of X-point radiator regime features in NSTX and DIII-D discharges with the snowflake divertor","authors":"V.A. Soukhanovskii ,&nbsp;S.L. Allen ,&nbsp;M.E. Fenstermacher ,&nbsp;C.J. Lasnier ,&nbsp;A.G. McLean ,&nbsp;F. Scotti ,&nbsp;E. Kolemen ,&nbsp;A. Diallo ,&nbsp;S. Gerhardt ,&nbsp;S. Kaye ,&nbsp;B.P. LeBlanc ,&nbsp;R. Maingi ,&nbsp;J.E. Menard ,&nbsp;R. Raman ,&nbsp;A.W. Hyatt ,&nbsp;A.W. Leonard ,&nbsp;T.H. Osborne ,&nbsp;The NSTX and DIII-D Teams","doi":"10.1016/j.nme.2024.101790","DOIUrl":"10.1016/j.nme.2024.101790","url":null,"abstract":"<div><div>Experimental data from NSTX and DIII-D discharges with the snowflake (SF) divertor configurations are analyzed toward the development of the X-point radiator (XPR) concept. The XPR divertor regime was recently realized in standard divertor configurations in several tokamaks The SF divertor configuration, with an additional poloidal field null nearby the main X-point, could provide additional benefits for the XPR: a higher flux expansion inside the separatrix and an extended private flux region. This may lead to lower temperatures and higher neutral and electron densities, which are thought to be essential for XPR stability, initiation, and impurity containment. In this work, 4 MW NBI-heated H-mode NSTX discharges and 3–5 MW NBI-heated H-mode DIII-D discharges with SF-minus and SF-plus divertors, with the ion <span><math><mrow><mi>B</mi><mo>×</mo><mo>∇</mo><mi>B</mi></mrow></math></span> drift toward the lower divertor, with and without D<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> and CD<span><math><msub><mrow></mrow><mrow><mn>4</mn></mrow></msub></math></span> seeding, were analyzed. Many experimental XPR features were found, including good or slightly degraded H-mode confinement, significant ELM size reduction, nearly complete divertor power detachment and a significant divertor radiated power loss. However, evidence of the XPR extending into the confined region was inconclusive in the NSTX tokamak, while in DIII-D, a number of discharges demonstrated a stable MARFE-like structure inside the separatrix over a wide operating space. The present analysis supports the SF divertor as a good candidate for further XPR scenario development in DIII-D and NSTX-U.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"41 ","pages":"Article 101790"},"PeriodicalIF":2.3,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142593472","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}