Pub Date : 2025-01-12DOI: 10.1016/j.nme.2025.101865
Yi-Cheng Chuang , Saskia Mordijck , Richard Fitzpatrick , Richard Reksoatmodjo
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.
{"title":"SOLPS-ITER simulations to study the impact of aspect ratio on edge fueling neutrals in tokamaks","authors":"Yi-Cheng Chuang , Saskia Mordijck , Richard Fitzpatrick , 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}
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.
{"title":"Effect of microstructure on hydrogen absorption in WMoTaNbV high-entropy alloy","authors":"Anna Liski , Marianna Kemell , Tomi Vuoriheimo , Ko-Kai Tseng , Ting-En Shen , Che-Wei Tsai , Jien-Wei Yeh , 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}
Pub Date : 2025-01-11DOI: 10.1016/j.nme.2025.101872
Y. Zayachuk , N. Catarino , J. Likonen , M. Rubel , A. Widdowson , JET contributors
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.
{"title":"Time dependence of fuel retention in JET be plasma-facing components – Comparison of single and multiple ITER-like wall campaigns","authors":"Y. Zayachuk , N. Catarino , J. Likonen , M. Rubel , A. Widdowson , 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}
Pub Date : 2025-01-11DOI: 10.1016/j.nme.2025.101873
Christoph Bläsius , Jürgen Sievers , Yongjian Gao , Stefan Weihe
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.
{"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 , Jürgen Sievers , Yongjian Gao , 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}
Pub Date : 2025-01-08DOI: 10.1016/j.nme.2025.101862
Ryuichi Sano, Tomohide Nakano, Shohei Yamoto
The transport of carbon and neon particles locally emitted from plasma facing components under the JT-60U L-mode plasma condition is investigated by the integrated divertor code SONIC. In this analysis, an impurity point source emitting a small amount of impurity particles functioning as tracers at the divertor target is added into previously calculated background plasma with changing point source location. For carbon, 60 percent or more of the emitted carbon particles from the attached area in inner/outer divertor target return and deposit onto the same inner/outer divertor target, respectively. For emitted carbon particles from the detached area, the ratio of deposition onto the divertor dome increases to around 50 percent. For neon impurity, 80 percent or more of emitted neon particles from the separatrix on the outer and inner divertor target are transported onto the outer and inner divertor target until first recycling experience, especially for low density cases. After the sequence of recycling experiences, the spatial neon density profile becomes similar, from whichever point source locations, outer or inner divertor neon is emitted. Results indicate that the location of the impurity source is not important for non-sticky impurities, such as neon. To control radiation profile by impurity source location, e.g., impurity puffing, non-sticky impurity is not effective.
{"title":"Simulation study on global migration of locally generated impurity in JT-60U","authors":"Ryuichi Sano, Tomohide Nakano, Shohei Yamoto","doi":"10.1016/j.nme.2025.101862","DOIUrl":"10.1016/j.nme.2025.101862","url":null,"abstract":"<div><div>The transport of carbon and neon particles locally emitted from plasma facing components under the JT-60U L-mode plasma condition is investigated by the integrated divertor code SONIC. In this analysis, an impurity point source emitting a small amount of impurity particles functioning as tracers at the divertor target is added into previously calculated background plasma with changing point source location. For carbon, 60 percent or more of the emitted carbon particles from the attached area in inner/outer divertor target return and deposit onto the same inner/outer divertor target, respectively. For emitted carbon particles from the detached area, the ratio of deposition onto the divertor dome increases to around 50 percent. For neon impurity, 80 percent or more of emitted neon particles from the separatrix on the outer and inner divertor target are transported onto the outer and inner divertor target until first recycling experience, especially for low density cases. After the sequence<!--> <!-->of recycling experiences, the spatial neon density profile becomes similar, from whichever point source locations, outer or inner divertor neon is emitted. Results indicate that the location of the impurity source is not important for non-sticky impurities, such as neon. To control radiation profile by impurity source location, e.g., impurity puffing, non-sticky impurity is not effective.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"42 ","pages":"Article 101862"},"PeriodicalIF":2.3,"publicationDate":"2025-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143173509","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}
Pub Date : 2025-01-08DOI: 10.1016/j.nme.2025.101871
Vladimir Chakin , Ramil Gaisin , Carsten Bonnekoh , Michael Duerrschnabel , Michael Rieth , Bronislava Gorr , Mikola Brodnikikovsky , Mikola Krapivka , Sergey Firstov
The study of chromium alloys, including the low-alloyed BX-2 K alloy and Cr-Fe alloys alloyed with Zr, Y, Al, Mn, Mo additions, after irradiation at temperatures ranging from 400 to 1000 °C and neutron fluences of (2.0 − 9.3) × 1026 m−2 (E > 0.1 MeV), corresponding to damage doses of 10–46 dpa, revealed a significant tendency for radiation embrittlement in all studied alloys. The tensile ductile-to-brittle transition temperature (DBTT) for these alloys increased to 250–700 °C after irradiation, while the initial DBTT was lower than room temperature. To enhance radiation embrittlement resistance, the Cr10FeZrY alloy, which exhibits a minimum DBTT of 250 °C, is recommended as a basis for further improvement of mechanical properties of Cr-Fe alloys under neutron irradiation.
{"title":"Embrittlement of chromium alloys after neutron irradiation at high temperatures to damage doses of 10–46 dpa","authors":"Vladimir Chakin , Ramil Gaisin , Carsten Bonnekoh , Michael Duerrschnabel , Michael Rieth , Bronislava Gorr , Mikola Brodnikikovsky , Mikola Krapivka , Sergey Firstov","doi":"10.1016/j.nme.2025.101871","DOIUrl":"10.1016/j.nme.2025.101871","url":null,"abstract":"<div><div>The study of chromium alloys, including the low-alloyed BX-2 K alloy and Cr-Fe alloys alloyed with Zr, Y, Al, Mn, Mo additions, after irradiation at temperatures ranging from 400 to 1000 °C and neutron fluences of (2.0 − 9.3) × 10<sup>26</sup> m<sup>−2</sup> (E > 0.1 MeV), corresponding to damage doses of 10–46 dpa, revealed a significant tendency for radiation embrittlement in all studied alloys. The tensile ductile-to-brittle transition temperature (DBTT) for these alloys increased to 250–700 °C after irradiation, while the initial DBTT was lower than room temperature. To enhance radiation embrittlement resistance, the Cr10FeZrY alloy, which exhibits a minimum DBTT of 250 °C, is recommended as a basis for further improvement of mechanical properties of Cr-Fe alloys under neutron irradiation.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"42 ","pages":"Article 101871"},"PeriodicalIF":2.3,"publicationDate":"2025-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143173090","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}
Pub Date : 2025-01-07DOI: 10.1016/j.nme.2025.101863
Huaqing Zheng , Xin Zhang , Jun Hu , Yuhong Xu , Guangjiu Lei , Sanqiu Liu , Heng Li , Zilin Cui , Yiqin Zhu , Xiaolong Li , Xiaoqiao Liu , Shaofei Geng , Xiaochang Chen , Haifeng Liu , Xianqu Wang , Hai Liu , Jun Cheng , Changjian Tang
This study used first-principles density functional theory with cp2k and VASP software to investigate the effects of Cs atoms adsorption on the work function of the LaB6 (100) surface. The results indicate that the most stable adsorption site for Cs atoms is at the top of the B atoms. The adsorption energy of Cs atoms was decomposed into three parts. The binding energy of the Cs layer on the deformed substrate has the largest contribution to the total adsorption energy and plays a dominant role. Although LaB6 is considered a potential Cs-free material, we found that Cs atom adsorption further lowers the surface work function compared to a clean LaB6 (100) model, facilitating electron emission. The change in work function is influenced by the dipole moment and is linearly related to changes in the dipole moment. Additionally, in systems with Cs atom adsorption, the charge rearrangement effect (Δp) dominates changes in the total dipole moment. These results provide some reference for the selection of fusion plasma gird materials and the production of hydrogen negative ion sources for neutral beam injection.
{"title":"Effect of Cs atoms adsorption on the work function of the LaB6 (100) surface","authors":"Huaqing Zheng , Xin Zhang , Jun Hu , Yuhong Xu , Guangjiu Lei , Sanqiu Liu , Heng Li , Zilin Cui , Yiqin Zhu , Xiaolong Li , Xiaoqiao Liu , Shaofei Geng , Xiaochang Chen , Haifeng Liu , Xianqu Wang , Hai Liu , Jun Cheng , Changjian Tang","doi":"10.1016/j.nme.2025.101863","DOIUrl":"10.1016/j.nme.2025.101863","url":null,"abstract":"<div><div>This study used first-principles density functional theory with cp2k and VASP software to investigate the effects of Cs atoms adsorption on the work function of the LaB<sub>6</sub> (100) surface. The results indicate that the most stable adsorption site for Cs atoms is at the top of the B atoms. The adsorption energy of Cs atoms was decomposed into three parts. The binding energy of the Cs layer on the deformed substrate has the largest contribution to the total adsorption energy and plays a dominant role. Although LaB<sub>6</sub> is considered a potential Cs-free material, we found that Cs atom adsorption further lowers the surface work function compared to a clean LaB<sub>6</sub> (100) model, facilitating electron emission. The change in work function is influenced by the dipole moment and is linearly related to changes in the dipole moment. Additionally, in systems with Cs atom adsorption, the charge rearrangement effect (Δp) dominates changes in the total dipole moment. These results provide some reference for the selection of fusion plasma gird materials and the production of hydrogen negative ion sources for neutral beam injection.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"42 ","pages":"Article 101863"},"PeriodicalIF":2.3,"publicationDate":"2025-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143173555","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}
Pub Date : 2025-01-07DOI: 10.1016/j.nme.2025.101861
Jingyang Han , Yaxiong He , Dongye Zhao , Laizhong Cai , Yiqin Wang , Wei Qian , Wenyu Huang , Yong Lu , Lijun Cai , Wulyu Zhong
In tokamaks, to understand the erosion and deposition pattern of plasma facing components (PFCs) is crucial for the study of plasma wall interaction (PWI). In this study, a set of dedicated marker graphite tiles consisting of substrate material same as the PFCs of HL-3 tokamak, an interlayer of 0.5 μm Tungsten (W) with width of 50 mm employed as marker, and a 5 μm thick with width of 30 mm carbon (C) marker layer on top, were designed and prepared for the PWI research. The magnetron sputtering technique was employed to make the marker layers including W and C layers. The scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDX) were used to study the surface morphology, elemental composition and layer structure characterization of marker graphite tiles. The Laser-induced breakdown spectroscopy (LIBS) was employed to perform elemental analysis along the depth direction of the C-W-C structure and W-C structure on the marker graphite tiles. Moreover, during the manufacturing process of marker graphite tiles, glass slides were used to be coated simultaneously with graphite and then measured by profilometer in order to evaluate the thickness of the coating. The cross-section of the marker graphite tiles measured by SEM revealed an average W interlayer thickness of 0.71 μm and an average C layer thickness of 4.75 μm. The LIBS results indicate that the thickness information of the C-W-C structure and the W-C structure is consistent with the findings from SEM analysis. The marker graphite tiles have been installed in HL-3 to perform the PWI studies including the C and W erosion, impurity deposition and material migration via surface element analysis and layer structure analysis of the marker graphite tiles in the next experimental campaign.
{"title":"Preparation and characterization of marker graphite tiles for PWI research of HL-3","authors":"Jingyang Han , Yaxiong He , Dongye Zhao , Laizhong Cai , Yiqin Wang , Wei Qian , Wenyu Huang , Yong Lu , Lijun Cai , Wulyu Zhong","doi":"10.1016/j.nme.2025.101861","DOIUrl":"10.1016/j.nme.2025.101861","url":null,"abstract":"<div><div>In tokamaks, to understand the erosion and deposition pattern of plasma facing components (PFCs) is crucial for the study of plasma wall interaction (PWI). In this study, a set of dedicated marker graphite tiles consisting of substrate material same as the PFCs of HL-3 tokamak, an interlayer of 0.5 μm Tungsten (W) with width of 50 mm employed as marker, and a 5 μm thick with width of 30 mm carbon (C) marker layer on top, were designed and prepared for the PWI research. The magnetron sputtering technique was employed to make the marker layers including W and C layers. The scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDX) were used to study the surface morphology, elemental composition and layer structure characterization of marker graphite tiles. The Laser-induced breakdown spectroscopy (LIBS) was employed to perform elemental analysis along the depth direction of the C-W-C structure and W-C structure on the marker graphite tiles. Moreover, during the manufacturing process of marker graphite tiles, glass slides were used to be coated simultaneously with graphite and then measured by profilometer in order to evaluate the thickness of the coating. The cross-section of the marker graphite tiles measured by SEM revealed an average W interlayer thickness of 0.71 μm and an average C layer thickness of 4.75 μm. The LIBS results indicate that the thickness information of the C-W-C structure and the W-C structure is consistent with the findings from SEM analysis. The marker graphite tiles have been installed in HL-3 to perform the PWI studies including the C and W erosion, impurity deposition and material migration via surface element analysis and layer structure analysis of the marker graphite tiles in the next experimental campaign.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"42 ","pages":"Article 101861"},"PeriodicalIF":2.3,"publicationDate":"2025-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143173489","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}
Pub Date : 2025-01-06DOI: 10.1016/j.nme.2024.101816
M. Fukumoto, T. Nakano, T. Wakatsuki, S. Kojima, Y. Ohtani, R. Sano, S. Inoue, H. Urano, M. Yoshida
<div><div>Hydrogen (<span><math><msub><mrow><mi>H</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span>) molecules were desorbed from the wall by tokamak discharges with helium (He) working gas. Particle balance analysis revealed that up to the same number of <span><math><msub><mrow><mi>H</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> molecules as the injected He atoms were evacuated per He tokamak discharge. Four sequences of Electron Cyclotron Wall Conditioning with He working gas (He-ECWC) performed after the second series of <span><math><msub><mrow><mi>H</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> tokamak discharges removed 16% of the <span><math><msub><mrow><mi>H</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> molecules that had been retained by the <span><math><msub><mrow><mi>H</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> tokamak discharges. The He-ECWC plasma produced by a fundamental ordinary mode (O1-mode) EC wave with a frequency of <span><math><mrow><msub><mrow><mi>f</mi></mrow><mrow><mi>EC</mi></mrow></msub><mo>=</mo></mrow></math></span> 82 GHz expanded along the poloidal magnetic field line. In the He-ECWC plasma produced by the O1-mode EC wave with <span><math><mrow><msub><mrow><mi>f</mi></mrow><mrow><mi>EC</mi></mrow></msub><mo>=</mo></mrow></math></span> 82 GHz, the <span><math><msub><mrow><mi>H</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> removal ratio relative to the residual <span><math><msub><mrow><mi>H</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> molecules was highest with the poloidal magnetic field in a Trapped Particle Configuration (TPC) with an <span><math><mi>n</mi></math></span>-index of 0.7 at the toroidal magnetic field of <span><math><mrow><msub><mrow><mi>B</mi></mrow><mrow><mi>T</mi></mrow></msub><mo>=</mo></mrow></math></span> 1.79 and 2.04 T. A comparable <span><math><msub><mrow><mi>H</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> removal ratio was observed with the poloidal magnetic field in a horizontal configuration at <span><math><mrow><msub><mrow><mi>B</mi></mrow><mrow><mi>T</mi></mrow></msub><mo>=</mo></mrow></math></span> 1.79 T. On a second harmonic extraordinary mode (X2-mode) EC wave with <span><math><mrow><msub><mrow><mi>f</mi></mrow><mrow><mi>EC</mi></mrow></msub><mo>=</mo></mrow></math></span> 110 GHz, the He-ECWC plasma was produced locally. For the He-ECWC with the X2-mode EC wave at <span><math><mrow><msub><mrow><mi>f</mi></mrow><mrow><mi>EC</mi></mrow></msub><mo>=</mo></mrow></math></span> 110 GHz, the number of removed <span><math><msub><mrow><mi>H</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> molecules did not change significantly between the different poloidal magnetic fields in the TPC at <span><math><mrow><msub><mrow><mi>B</mi></mrow><mrow><mi>T</mi></mrow></msub><mo>=</mo></mrow></math></span> 1.79 and 2.04 T. No He-ECWC plasma was observed with the poloidal magnetic field in the horizontal magnetic configur
{"title":"Effects of poloidal magnetic configurations on expansions of electron cyclotron wall conditioning plasma and hydrogen removal in the integrated commissioning phase of JT-60SA","authors":"M. Fukumoto, T. Nakano, T. Wakatsuki, S. Kojima, Y. Ohtani, R. Sano, S. Inoue, H. Urano, M. Yoshida","doi":"10.1016/j.nme.2024.101816","DOIUrl":"10.1016/j.nme.2024.101816","url":null,"abstract":"<div><div>Hydrogen (<span><math><msub><mrow><mi>H</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span>) molecules were desorbed from the wall by tokamak discharges with helium (He) working gas. Particle balance analysis revealed that up to the same number of <span><math><msub><mrow><mi>H</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> molecules as the injected He atoms were evacuated per He tokamak discharge. Four sequences of Electron Cyclotron Wall Conditioning with He working gas (He-ECWC) performed after the second series of <span><math><msub><mrow><mi>H</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> tokamak discharges removed 16% of the <span><math><msub><mrow><mi>H</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> molecules that had been retained by the <span><math><msub><mrow><mi>H</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> tokamak discharges. The He-ECWC plasma produced by a fundamental ordinary mode (O1-mode) EC wave with a frequency of <span><math><mrow><msub><mrow><mi>f</mi></mrow><mrow><mi>EC</mi></mrow></msub><mo>=</mo></mrow></math></span> 82 GHz expanded along the poloidal magnetic field line. In the He-ECWC plasma produced by the O1-mode EC wave with <span><math><mrow><msub><mrow><mi>f</mi></mrow><mrow><mi>EC</mi></mrow></msub><mo>=</mo></mrow></math></span> 82 GHz, the <span><math><msub><mrow><mi>H</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> removal ratio relative to the residual <span><math><msub><mrow><mi>H</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> molecules was highest with the poloidal magnetic field in a Trapped Particle Configuration (TPC) with an <span><math><mi>n</mi></math></span>-index of 0.7 at the toroidal magnetic field of <span><math><mrow><msub><mrow><mi>B</mi></mrow><mrow><mi>T</mi></mrow></msub><mo>=</mo></mrow></math></span> 1.79 and 2.04 T. A comparable <span><math><msub><mrow><mi>H</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> removal ratio was observed with the poloidal magnetic field in a horizontal configuration at <span><math><mrow><msub><mrow><mi>B</mi></mrow><mrow><mi>T</mi></mrow></msub><mo>=</mo></mrow></math></span> 1.79 T. On a second harmonic extraordinary mode (X2-mode) EC wave with <span><math><mrow><msub><mrow><mi>f</mi></mrow><mrow><mi>EC</mi></mrow></msub><mo>=</mo></mrow></math></span> 110 GHz, the He-ECWC plasma was produced locally. For the He-ECWC with the X2-mode EC wave at <span><math><mrow><msub><mrow><mi>f</mi></mrow><mrow><mi>EC</mi></mrow></msub><mo>=</mo></mrow></math></span> 110 GHz, the number of removed <span><math><msub><mrow><mi>H</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> molecules did not change significantly between the different poloidal magnetic fields in the TPC at <span><math><mrow><msub><mrow><mi>B</mi></mrow><mrow><mi>T</mi></mrow></msub><mo>=</mo></mrow></math></span> 1.79 and 2.04 T. No He-ECWC plasma was observed with the poloidal magnetic field in the horizontal magnetic configur","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"42 ","pages":"Article 101816"},"PeriodicalIF":2.3,"publicationDate":"2025-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143173096","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}
Pub Date : 2025-01-06DOI: 10.1016/j.nme.2024.101859
K. Saito , D. Hwangbo , M. Miyamoto , H. Yoshida , R. Sasaki , S. Murakami , M. Sakamoto
The release of deuterium (D) atoms from a nanostructure ‘fuzz’ tungsten (W) after a sequential plasma irradiation of helium (He) and D was explored. Thermal desorption spectroscopy revealed that more than 60% of total D amount was already released at 423 K. A sophisticated measurement with an aberration-corrected scanning TEM combined with electron energy-loss spectrometer (STEM-EELS) directly showed the trapping of D atoms into He bubbles after the plasma irradiation and the release of D from the He bubbles at elevated temperature at 423 K. The He bubbles containing D were characterized by (i) relatively large volume and (ii) small He energy-loss shift below 2 eV. It is suggested that the shifts in the energy-loss peaks of He and D could be used as indicators of D absorption within He bubbles.
{"title":"Trapping and release of deuterium in helium-induced tungsten fuzz at low temperature","authors":"K. Saito , D. Hwangbo , M. Miyamoto , H. Yoshida , R. Sasaki , S. Murakami , M. Sakamoto","doi":"10.1016/j.nme.2024.101859","DOIUrl":"10.1016/j.nme.2024.101859","url":null,"abstract":"<div><div>The release of deuterium (D) atoms from a nanostructure ‘fuzz’ tungsten (W) after a sequential plasma irradiation of helium (He) and D was explored. Thermal desorption spectroscopy revealed that more than 60% of total D amount was already released at <span><math><mo>></mo></math></span>423 K. A sophisticated measurement with an aberration-corrected scanning TEM combined with electron energy-loss spectrometer (STEM-EELS) directly showed the trapping of D atoms into He bubbles after the plasma irradiation and the release of D from the He bubbles at elevated temperature at 423 K. The He bubbles containing D were characterized by (i) relatively large volume and (ii) small He energy-loss shift below 2 eV. It is suggested that the shifts in the energy-loss peaks of He and D could be used as indicators of D absorption within He bubbles.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"42 ","pages":"Article 101859"},"PeriodicalIF":2.3,"publicationDate":"2025-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143173093","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}
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