Pub Date : 2025-11-04DOI: 10.1016/j.nme.2025.102019
Wei Wu , Yi-Lang Mai , Ya-Wen Li , Ziqi Li , Xiao-Chun Li , Jinlong Wang , Hai-Shan Zhou , Guang-Nan Luo
In this study, molecular dynamics simulations were performed to systematically investigate the implantation and desorption behavior of hydrogen (H) on three α-iron (Fe) surfaces: (100), (112), and (110), under projectile energies ranging from 10 to 100 eV. It is found that H retention increases with increasing projectile energy. This trend is attributed to the positive correlation between the average implantation depth and the projectile energy. Moreover, the implanted H tends to aggregate into plate-like structures, which further hinder its diffusion toward the surface. We conducted a detailed analysis of the desorption mechanisms of adsorbed H and found that the amount of desorbed H is negatively correlated with the projectile energy. This phenomenon is attributed to the fact that lower projectile energies lead to increased reflection rates, and the reflected H facilitate the desorption of adsorbed H. These findings provide important insights into the microscopic mechanisms of H desorption under fusion-relevant conditions.
{"title":"Energy-dependent study on H retention and desorption behavior on α-Fe surfaces","authors":"Wei Wu , Yi-Lang Mai , Ya-Wen Li , Ziqi Li , Xiao-Chun Li , Jinlong Wang , Hai-Shan Zhou , Guang-Nan Luo","doi":"10.1016/j.nme.2025.102019","DOIUrl":"10.1016/j.nme.2025.102019","url":null,"abstract":"<div><div>In this study, molecular dynamics simulations were performed to systematically investigate the implantation and desorption behavior of hydrogen (H) on three α-iron (Fe) surfaces: (100), (112), and (110), under projectile energies ranging from 10 to 100 eV. It is found that H retention increases with increasing projectile energy. This trend is attributed to the positive correlation between the average implantation depth and the projectile energy. Moreover, the implanted H tends to aggregate into plate-like structures, which further hinder its diffusion toward the surface. We conducted a detailed analysis of the desorption mechanisms of adsorbed H and found that the amount of desorbed H is negatively correlated with the projectile energy. This phenomenon is attributed to the fact that lower projectile energies lead to increased reflection rates, and the reflected H facilitate the desorption of adsorbed H. These findings provide important insights into the microscopic mechanisms of H desorption under fusion-relevant conditions.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"45 ","pages":"Article 102019"},"PeriodicalIF":2.7,"publicationDate":"2025-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145528702","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}
Pub Date : 2025-11-03DOI: 10.1016/j.nme.2025.102020
Song Xu , Ji-Chao Wang , Xianhua Li , Xiancai Meng , Lizhen Liang
This study systematically examines how brazing temperature influences interfacial intermetallic compounds (IMCs) formation and properties in Mo/BNi2/304L stainless steel joints for the EAST NBI electrode. Process parameters are optimized to enhance joint mechanical properties. Results reveal a layered interfacial microstructure: Mo/Mo2NiB2+ Ni3Si/Ni3B + Ni-based solid solution + Cr-B/Cr2B + Fe-Ni solid solution/ 304L. IMC development progresses from the interface inward: Mo2NiB2, Ni3Si, Cr2B form immediately at the interfaces during brazing, while brittle phases (Ni3B, Cr-B) form in the brazing seam center during cooling. Notably, the Mo2NiB2 layer is the weakest part of the interface. Brazing temperature primarily affects joint strength by altering the thickness of Zone I (Mo2NiB2, Ni3Si), with peak shear strength observed at 1000 °C.
{"title":"Effect of temperature on intermetallic compound formation and mechanical properties of Mo/BNi2/304L vacuum brazed joints","authors":"Song Xu , Ji-Chao Wang , Xianhua Li , Xiancai Meng , Lizhen Liang","doi":"10.1016/j.nme.2025.102020","DOIUrl":"10.1016/j.nme.2025.102020","url":null,"abstract":"<div><div>This study systematically examines how brazing temperature influences interfacial intermetallic compounds (IMCs) formation and properties in Mo/BNi2/304L stainless steel joints for the EAST NBI electrode. Process parameters are optimized to enhance joint mechanical properties. Results reveal a layered interfacial microstructure: Mo/Mo<sub>2</sub>NiB<sub>2</sub>+ Ni<sub>3</sub>Si/Ni<sub>3</sub>B + Ni-based solid solution + Cr-B/Cr<sub>2</sub>B + Fe-Ni solid solution/ 304L. IMC development progresses from the interface inward: Mo<sub>2</sub>NiB<sub>2</sub>, Ni<sub>3</sub>Si, Cr<sub>2</sub>B form immediately at the interfaces during brazing, while brittle phases (Ni<sub>3</sub>B, Cr-B) form in the brazing seam center during cooling. Notably, the Mo<sub>2</sub>NiB<sub>2</sub> layer is the weakest part of the interface. Brazing temperature primarily affects joint strength by altering the thickness of Zone I (Mo<sub>2</sub>NiB<sub>2</sub>, Ni<sub>3</sub>Si), with peak shear strength observed at 1000 °C.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"45 ","pages":"Article 102020"},"PeriodicalIF":2.7,"publicationDate":"2025-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145474208","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}
Pub Date : 2025-10-31DOI: 10.1016/j.nme.2025.102018
Huace Wu , Rongxing Yi , Sebastijan Brezinsek , Anne Houben , Marcin Rasinski , Rui Ding , Matej Mayer , Gennady Sergienko , Timo Dittmar , Hongbin Ding
The impact of the thickness and uniformity of boron (B) layer deposited by the boronization process, as well as the understanding of the layer’s lifetime and oxygen gettering effectivity, remains uncertain and real time diagnosis is required in future. Building upon our previous work, the picosecond laser-induced breakdown spectroscopy (ps-LIBS) technology with spatial resolution capability was further employed to detect B elements in B films deposited on tungsten (W)-substrates samples. By adjusting experimental parameters such as laser energy and spot size, and studying the spatiotemporal evolution of W and B elements, the optimal experimental parameters were determined. Under a laser spot diameter of 488 μm, a laser fluence of 9.6 J/cm2, a delay time of 30 ns, and a gate width of 600 ns were used to improve the limit of detection (LOD) of B by ps-LIBS. A set of samples with different B layer thicknesses on W-substrates from 5.6 to 151.5 nm was obtained through exposure of samples by magnetron sputtering in a laboratory arrangement and exposure of samples on a manipulator during two boronizations in the stellarator W7-X. The thickness of the B layers was measured by Focused Ion Beam combined with Scanning Electron Microscopy (FIB-SEM) and Nuclear Reaction Analysis (NRA). After extracting the net B signal from the LIBS spectra, a quantitative calibration curve and LOD of the B II-703.2 nm for the B layers on W-substrates were established for the first time. These results confirm that ps-LIBS technology holds promise for in situ diagnostics of ultrathin B layers, ranging from a few nm to 100 nm, on W-substrates in fusion devices after boronization.
{"title":"Ultrathin boron layer (a few nm to 100 nm) diagnostics on tungsten substrates via spatiotemporally resolved picosecond LIBS in a vacuum","authors":"Huace Wu , Rongxing Yi , Sebastijan Brezinsek , Anne Houben , Marcin Rasinski , Rui Ding , Matej Mayer , Gennady Sergienko , Timo Dittmar , Hongbin Ding","doi":"10.1016/j.nme.2025.102018","DOIUrl":"10.1016/j.nme.2025.102018","url":null,"abstract":"<div><div>The impact of the thickness and uniformity of boron (B) layer deposited by the boronization process, as well as the understanding of the layer’s lifetime and oxygen gettering effectivity, remains uncertain and real time diagnosis is required in future. Building upon our previous work, the picosecond laser-induced breakdown spectroscopy (ps-LIBS) technology with spatial resolution capability was further employed to detect B elements in B films deposited on tungsten (W)-substrates samples. By adjusting experimental parameters such as laser energy and spot size, and studying the spatiotemporal evolution of W and B elements, the optimal experimental parameters were determined. Under a laser spot diameter of 488 μm, a laser fluence of 9.6 J/cm<sup>2</sup>, a delay time of 30 ns, and a gate width of 600 ns were used to improve the limit of detection (LOD) of B by ps-LIBS. A set of samples with different B layer thicknesses on W-substrates from 5.6 to 151.5 nm was obtained through exposure of samples by magnetron sputtering in a laboratory arrangement and exposure of samples on a manipulator during two boronizations in the stellarator W7-X. The thickness of the B layers was measured by Focused Ion Beam combined with Scanning Electron Microscopy (FIB-SEM) and Nuclear Reaction Analysis (NRA). After extracting the net B signal from the LIBS spectra, a quantitative calibration curve and LOD of the B II-703.2 nm for the B layers on W-substrates were established for the first time. These results confirm that ps-LIBS technology holds promise for <em>in situ</em> diagnostics of ultrathin B layers, ranging from a few nm to 100 nm, on W-substrates in fusion devices after boronization.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"45 ","pages":"Article 102018"},"PeriodicalIF":2.7,"publicationDate":"2025-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145473641","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}
Pub Date : 2025-10-30DOI: 10.1016/j.nme.2025.102017
A. Huart , G. Ciraolo , Y. Corre , N. Rivals , J.P. Gunn , C. Guillemaut , N. Fedorczak , A. Grosjean , C. Johnson , J. Gerardin , M. Diez , J. Romazanov , W. Gromelski , WP TE team, the WEST team
A deuterium high-fluence experimental campaign under changeless condition with attached plasma at the divertor strike lines was conducted in the WEST tokamak (spring 2023) to expose the ITER-grade actively-cooled divertor to ITER-relevant particle fluences by repeating the same plasma scenario of 70 s each on average, with a total cumulated plasma time of 10790 s. The goal of this work is to understand the erosion/deposition patterns observed on the divertor after the campaign by modeling the plasma conditions and the transport of tungsten. Impurities sources are monitored by visible spectroscopy, showing high content of boron and carbon all along the campaign especially on the high-field side where deposited layers are growing continuously. An analysis using visible spectroscopy (for WI 4009 Å radiance) and flush-mounted Langmuir probe measurements (to obtain ne and Te dependent local S/XB coefficients) gives estimates of the tungsten gross erosion flux up to 1.5 × 1019 part.m−2.s−1, leading to around 0.67 μm of net erosion near the outer strike point, assuming the high fluence campaign plasma time and 75 % prompt redeposition rates, while post-mortem analysis suggests higher values (around 7 μm of net erosion on the inner strike point) after both, foregoing and high-fluence campaign. To model those experimental observations, the first step is to simulate a plasma background with SOLEDGE3X-EIRENE, constrained by experimental measurements. Plasma backgrounds are simulated with proxy light impurity (O) with various concentrations (1 to 5 %) to match experimental conditions (particle flux and electron temperature at the edge). ERO2.0 simulates the transport of tungsten using the SOLEDGE3X-EIRENE plasma background and gives eroded and deposited tungsten flux on the wall. The final simulated erosion depth is barely the same for each oxygen concentrations and around 4 to 9 µm at both strike-points which is consistent with firsts estimates by post-mortem analysis. The far inner redeposition area is not recovered in the simulation and is subject to further work.
{"title":"Modeling of erosion/deposition patterns observed during WEST high-fluence campaign","authors":"A. Huart , G. Ciraolo , Y. Corre , N. Rivals , J.P. Gunn , C. Guillemaut , N. Fedorczak , A. Grosjean , C. Johnson , J. Gerardin , M. Diez , J. Romazanov , W. Gromelski , WP TE team, the WEST team","doi":"10.1016/j.nme.2025.102017","DOIUrl":"10.1016/j.nme.2025.102017","url":null,"abstract":"<div><div>A deuterium high-fluence experimental campaign under changeless condition with attached plasma at the divertor strike lines was conducted in the WEST tokamak (spring 2023) to expose the ITER-grade actively-cooled divertor to ITER-relevant particle fluences by repeating the same plasma scenario of 70 s each on average, with a total cumulated plasma time of 10790 s. The goal of this work is to understand the erosion/deposition patterns observed on the divertor after the campaign by modeling the plasma conditions and the transport of tungsten. Impurities sources are monitored by visible spectroscopy, showing high content of boron and carbon all along the campaign especially on the high-field side where deposited layers are growing continuously. An analysis using visible spectroscopy (for WI 4009 Å radiance) and flush-mounted Langmuir probe measurements (to obtain n<sub>e</sub> and T<sub>e</sub> dependent local S/XB coefficients) gives estimates of the tungsten gross erosion flux up to 1.5 × 10<sup>19</sup> part.m<sup>−2</sup>.s<sup>−1</sup>, leading to around 0.67 μm of net erosion near the outer strike point, assuming the high fluence campaign plasma time and 75 % prompt redeposition rates, while post-mortem analysis suggests higher values (around 7 μm of net erosion on the inner strike point) after both, foregoing and high-fluence campaign. To model those experimental observations, the first step is to simulate a plasma background with SOLEDGE3X-EIRENE, constrained by experimental measurements. Plasma backgrounds are simulated with proxy light impurity (O) with various concentrations (1 to 5 %) to match experimental conditions (particle flux and electron temperature at the edge). ERO2.0 simulates the transport of tungsten using the SOLEDGE3X-EIRENE plasma background and gives eroded and deposited tungsten flux on the wall. The final simulated erosion depth is barely the same for each oxygen concentrations and around 4 to 9 µm at both strike-points which is consistent with firsts estimates by post-mortem analysis. The far inner redeposition area is not recovered in the simulation and is subject to further work.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"45 ","pages":"Article 102017"},"PeriodicalIF":2.7,"publicationDate":"2025-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145417637","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}
Pub Date : 2025-10-24DOI: 10.1016/j.nme.2025.102014
J.P. Pollard , T. Zagyva , C.S.J. Pickles , J.O. Astbury , C.G. Windsor , A. Shivprasad , C.A. Kohnert , F. Giuliani , S. Humphry-Baker
Thermophysical properties are reported on ε-HfH2 samples fabricated by powder metallurgy. Samples were heat treated in the range 300–550 °C to transform them from ε-HfH2 to δ-HfH1.6-x, allowing comparison of the properties of both phases. Higher molar heat capacity was found in stoichiometric ε-HfH2 compared to literature data on sub-stoichiometric ε-HfH1.83. The δ-phase undergoes a vacancy order–disorder transformation at ∼130 °C with a transformation enthalpy of ∼1.4 kJ mol−1. The room-temperature thermal diffusivity of the ε and δ phases were 0.11 and 0.09 cm2 s−1 respectively. These values are lower than those for literature bulk hydride materials, which is accounted for by pore-phonon scattering. Thermal expansion of ε and δ phases was measured by high-temperature X-ray diffraction to be 9.2 and 11 x10-6 K−1, respectively. The data on the ε phase is the first known in the literature. The thermal expansion was highly anisotropic, with a negative thermal expansion parallel to the a-axis (Ra = −8.7). Such extreme anisotropy has implications in controlling the microstructure for thermal damage tolerance.
{"title":"Thermophysical properties and expansion anisotropy of sintered hafnium hydride compacts","authors":"J.P. Pollard , T. Zagyva , C.S.J. Pickles , J.O. Astbury , C.G. Windsor , A. Shivprasad , C.A. Kohnert , F. Giuliani , S. Humphry-Baker","doi":"10.1016/j.nme.2025.102014","DOIUrl":"10.1016/j.nme.2025.102014","url":null,"abstract":"<div><div>Thermophysical properties are reported on ε-HfH<sub>2</sub> samples fabricated by powder metallurgy. Samples were heat treated in the range 300–550 °C to transform them from ε-HfH<sub>2</sub> to δ-HfH<sub>1.6-x</sub>, allowing comparison of the properties of both phases. Higher molar heat capacity was found in stoichiometric ε-HfH<sub>2</sub> compared to literature data on sub-stoichiometric ε-HfH<sub>1.83</sub>. The δ-phase undergoes a vacancy order–disorder transformation at ∼130 °C with a transformation enthalpy of ∼1.4 kJ mol<sup>−1</sup>. The room-temperature thermal diffusivity of the ε and δ phases were 0.11 and 0.09 cm<sup>2</sup> s<sup>−1</sup> respectively. These values are lower than those for literature bulk hydride materials, which is accounted for by pore-phonon scattering. Thermal expansion of ε and δ phases was measured by high-temperature X-ray diffraction to be 9.2 and 11 x10<sup>-6</sup> K<sup>−1</sup>, respectively. The data on the ε phase is the first known in the literature. The thermal expansion was highly anisotropic, with a negative thermal expansion parallel to the a-axis (R<sub>a</sub> = −8.7). Such extreme anisotropy has implications in controlling the microstructure for thermal damage tolerance.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"45 ","pages":"Article 102014"},"PeriodicalIF":2.7,"publicationDate":"2025-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145417636","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}
Pub Date : 2025-10-22DOI: 10.1016/j.nme.2025.102016
Rongxing Yi , Rahul Rayaprolu , Jari Likonen , Salvatore Almaviva , Ionut Jepu , Gennady Sergienko , Anna Widdowson , Nick Jones , Sahithya Atikukke , Timo Dittmar , Juuso Karhunen , Pawel Gasior , Marc Sackers , Shweta Soni , Erik Wüst , Jelena Butikova , Wojciech Gromelski , Antti Hakola , Indrek Jõgi , Peeter Paris , Sebastijan Brezinsek
The tokamak JET achieved a groundbreaking milestone in nuclear fusion during its final deuterium–tritium experimental campaign (DTE-3) by setting a new world energy record [1]. To investigate in-vessel the fuel retention and wall material migration in JET post DT operation and clean-up phase with baking and glow discharge cleaning, a laptop-sized laser-induced breakdown spectroscopy (LIBS) system was deployed and mounted on a remote handling arm inside JET. The 800 ps (10 mJ) laser (wavelength 1064 nm) achieved a spatial and depth resolution of 130 μm and 180 nm on tungsten plasma-facing components (1000 pulses), respectively. Over 800 positions including beryllium first wall and tungsten divertor were studied by LIBS and provided both the spatial distribution and depth profiles of retained hydrogen (H) isotopes. LIBS spectra from four spectrometer systems enabled both high-resolution, high-sensitivity measurements and a broad spectral range simultaneously. Among them, a high throughput and high spectral resolution spectrometer in Littrow-arrangement was applied to distinguish the hydrogen isotopes. This in-vessel analysis demonstration provides vital information about the applicability of the technique for retention studies in future fusion reactors.
{"title":"In-vessel and depth-resolved semi-quantitative analysis on hydrogen isotopes and wall materials in JET by LIBS operated on a remote handling arm","authors":"Rongxing Yi , Rahul Rayaprolu , Jari Likonen , Salvatore Almaviva , Ionut Jepu , Gennady Sergienko , Anna Widdowson , Nick Jones , Sahithya Atikukke , Timo Dittmar , Juuso Karhunen , Pawel Gasior , Marc Sackers , Shweta Soni , Erik Wüst , Jelena Butikova , Wojciech Gromelski , Antti Hakola , Indrek Jõgi , Peeter Paris , Sebastijan Brezinsek","doi":"10.1016/j.nme.2025.102016","DOIUrl":"10.1016/j.nme.2025.102016","url":null,"abstract":"<div><div>The tokamak JET achieved a groundbreaking milestone in nuclear fusion during its final deuterium–tritium experimental campaign (DTE-3) by setting a new world energy record [<span><span>1</span></span>]. To investigate in-vessel the fuel retention and wall material migration in JET post DT operation and clean-up phase with baking and glow discharge cleaning, a laptop-sized laser-induced breakdown spectroscopy (LIBS) system was deployed and mounted on a remote handling arm inside JET. The 800 ps (10 mJ) laser (wavelength 1064 nm) achieved a spatial and depth resolution of 130 μm and 180 nm on tungsten plasma-facing components (1000 pulses), respectively. Over 800 positions including beryllium first wall and tungsten divertor were studied by LIBS and provided both the spatial distribution and depth profiles of retained hydrogen (H) isotopes. LIBS spectra from four spectrometer systems enabled both high-resolution, high-sensitivity measurements and a broad spectral range simultaneously. Among them, a high throughput and high spectral resolution spectrometer in Littrow-arrangement was applied to distinguish the hydrogen isotopes. This in-vessel analysis demonstration provides vital information about the applicability of the technique for retention studies in future fusion reactors.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"45 ","pages":"Article 102016"},"PeriodicalIF":2.7,"publicationDate":"2025-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145362923","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}
Pub Date : 2025-10-22DOI: 10.1016/j.nme.2025.102015
M. Mayer , S. An , T. Bräuer , D. Cipciar , C.P. Dhard , C. Killer , D. Naujoks , V. Rohde , R. Steinwehr , U. von Toussaint , L. Vano , H. Viebke , W7-X Team, ASDEX Upgrade Team
The surface loss probabilities of boron-hydride radicals on silicon surfaces have been measured during boronisations for wall conditioning in the stellarator W7-X and the tokamak ASDEX Upgrade using the cavity technique. The boronisations were performed using a glow-discharge plasma with a mixture of 10 % diborane (B2H6 in W7-X, B2D6 in ASDEX Upgrade) and 90 % Helium at voltages of 300–500 V. Molecular ion species and neutral radicals were distinguished by their incident distributions inside the cavities. In W7-X the incident particles were dominantly ions with 80–95 % contribution to the incident flux, while in ASDEX Upgrade the ion flux contribution was about 65 %. The surface loss probability of the ionic species was about 0.2. One neutral species with surface loss probability close to unity was deduced.
{"title":"Surface loss probabilities of boron-hydride radicals in W7-X and ASDEX Upgrade","authors":"M. Mayer , S. An , T. Bräuer , D. Cipciar , C.P. Dhard , C. Killer , D. Naujoks , V. Rohde , R. Steinwehr , U. von Toussaint , L. Vano , H. Viebke , W7-X Team, ASDEX Upgrade Team","doi":"10.1016/j.nme.2025.102015","DOIUrl":"10.1016/j.nme.2025.102015","url":null,"abstract":"<div><div>The surface loss probabilities of boron-hydride radicals on silicon surfaces have been measured during boronisations for wall conditioning in the stellarator W7-X and the tokamak ASDEX Upgrade using the cavity technique. The boronisations were performed using a glow-discharge plasma with a mixture of 10 % diborane (B<sub>2</sub>H<sub>6</sub> in W7-X, B<sub>2</sub>D<sub>6</sub> in ASDEX Upgrade) and 90 % Helium at voltages of 300–500 <!--> <!-->V. Molecular ion species and neutral radicals were distinguished by their incident distributions inside the cavities. In W7-X the incident particles were dominantly ions with 80–95 % contribution to the incident flux, while in ASDEX Upgrade the ion flux contribution was about 65 %. The surface loss probability of the ionic species was about 0.2. One neutral species with surface loss probability close to unity was deduced.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"45 ","pages":"Article 102015"},"PeriodicalIF":2.7,"publicationDate":"2025-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145417638","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}
Using SUS304L stainless steel, which is employed in reactor structural components, the effects of grain refinement on stress corrosion cracking occurring under nuclear reactor operating conditions were investigated. As a result, after conducting slow strain rate testing (SSRT) in air and nuclear reactor operating environments, a comparison of the tensile properties of SUS304L with the same grain size revealed that elongation significantly decreased with increasing grain size under nuclear reactor operating conditions. In SSRT conducted in air, the -value obtained from the Hall–Petch relationship was lower than the conventional values. Observations showed the absence of cracks on SUS304L with 0.59 and 1.52 µm grains; however, SUS304L with larger grains exhibited rougher fracture surfaces and side cracks. Thin oxide films were formed on SUS304L with 0.59 µm and 1.52 µm grains, while SUS304L with coarse grains of 28.4 µm or larger enabled the formation of oxide films with over 2 µm thickness. Cr2O3 films were formed on SUS304L with 0.59 µm, 1.52 µm, and 28.4 µm, while Cr2O3 and Fe-based oxides were formed on SUS304L with 39.5 µm and 68.6 µm. Crystal orientation analysis revealed linear surface layers without cracks in the γ-phase for SUS304L with 0.59 µm and 1.52 µm. In materials with larger grain sizes, surface irregularities and cracks were observed in the γ-phase. In fine-grained SUS304L, lattice diffusion caused uniform O diffusion in the γ-phase, resulting in the formation of a thin Cr2O3 layer that suppressed cracks. In coarse-grained SUS304L, grain boundary diffusion caused Fe oxide formation at the grain boundaries, weakening them, and supersaturated O led to the formation of thick films comprising Cr2O3 and Fe-based oxides, resulting in peeling and cracking.
{"title":"Effect of grain refinement on cracks occurring in SUS304L stainless steel under nuclear reactor operating conditions","authors":"Noriaki Hirota , Ryoma Takeda , Hiroshi ide , Kunihiko Tsuchiya , Yoshinao Kobayashi","doi":"10.1016/j.nme.2025.102009","DOIUrl":"10.1016/j.nme.2025.102009","url":null,"abstract":"<div><div>Using SUS304L stainless steel, which is employed in reactor structural components, the effects of grain refinement on stress corrosion cracking occurring under nuclear reactor operating conditions were investigated. As a result, after conducting slow strain rate testing (SSRT) in air and nuclear reactor operating environments, a comparison of the tensile properties of SUS304L with the same grain size revealed that elongation significantly decreased with increasing grain size under nuclear reactor operating conditions. In SSRT conducted in air, the <span><math><mi>k</mi></math></span>-value obtained from the Hall–Petch relationship was lower than the conventional values. Observations showed the absence of cracks on SUS304L with 0.59 and 1.52 µm grains; however, SUS304L with larger grains exhibited rougher fracture surfaces and side cracks. Thin oxide films were formed on SUS304L with 0.59 µm and 1.52 µm grains, while SUS304L with coarse grains of 28.4 µm or larger enabled the formation of oxide films with over 2 µm thickness. Cr<sub>2</sub>O<sub>3</sub> films were formed on SUS304L with 0.59 µm, 1.52 µm, and 28.4 µm, while Cr<sub>2</sub>O<sub>3</sub> and Fe-based oxides were formed on SUS304L with 39.5 µm and 68.6 µm. Crystal orientation analysis revealed linear surface layers without cracks in the γ-phase for SUS304L with 0.59 µm and 1.52 µm. In materials with larger grain sizes, surface irregularities and cracks were observed in the γ-phase. In fine-grained SUS304L, lattice diffusion caused uniform O diffusion in the γ-phase, resulting in the formation of a thin Cr<sub>2</sub>O<sub>3</sub> layer that suppressed cracks. In coarse-grained SUS304L, grain boundary diffusion caused Fe oxide formation at the grain boundaries, weakening them, and supersaturated O led to the formation of thick films comprising Cr<sub>2</sub>O<sub>3</sub> and Fe-based oxides, resulting in peeling and cracking.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"45 ","pages":"Article 102009"},"PeriodicalIF":2.7,"publicationDate":"2025-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145362922","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}
Pub Date : 2025-10-17DOI: 10.1016/j.nme.2025.102011
Miguel Zavala-Arredondo , Arun Ramanathan Balachandramurthi , Lidija Stjepanic Peric , Nick Weston , Katy Rankin , Sebastian Rosini , Khurram Amjad , Jeong-Ha You
Pure tungsten is one of the promising candidate materials for plasma facing components (PFC) of future fusion reactors due to several favourable properties including its high melting point, high thermal conductivity, high strength, high sputtering resistivity and low coefficient of thermal expansion. Increasing geometric complexity and productivity of tungsten PFC is of interest to improve thermal performance and availability for new tokamaks with a view to future steady state plasma operation. Additive manufacturing (AM) by the electron beam powder-bed-fusion process (EB-PBF) is identified as a potential technology to address these requirements. In this paper we reviewed the literature in EB-PBF of unalloyed tungsten to understand the role that the manufacturing parameters have in the microstructure and mechanical performance of as-printed specimens. We present targeted key research in tungsten EB-PBF process development using a modulated point melting method, post-AM hot isostatic pressing (HIP) treatment, destructive and non-destructive evaluation, microstructure control, and in-process monitoring. It was found that the modulated point melting method reduces cleavage cracking and crack nucleation points while elevated temperature HIP treatment improves the repeatability of the tensile behaviour, while mechanically healing process induced defects like solid-state cracks and nanopores.
{"title":"Investigating the microstructure of additively manufactured tungsten parts produced by electron beam powder bed fusion process","authors":"Miguel Zavala-Arredondo , Arun Ramanathan Balachandramurthi , Lidija Stjepanic Peric , Nick Weston , Katy Rankin , Sebastian Rosini , Khurram Amjad , Jeong-Ha You","doi":"10.1016/j.nme.2025.102011","DOIUrl":"10.1016/j.nme.2025.102011","url":null,"abstract":"<div><div>Pure tungsten is one of the promising candidate materials for plasma facing components (PFC) of future fusion reactors due to several favourable properties including its high melting point, high thermal conductivity, high strength, high sputtering resistivity and low coefficient of thermal expansion. Increasing geometric complexity and productivity of tungsten PFC is of interest to improve thermal performance and availability for new tokamaks with a view to future steady state plasma operation. Additive manufacturing (AM) by the electron beam powder-bed-fusion process (EB-PBF) is identified as a potential technology to address these requirements. In this paper we reviewed the literature in EB-PBF of unalloyed tungsten to understand the role that the manufacturing parameters have in the microstructure and mechanical performance of as-printed specimens. We present targeted key research in tungsten EB-PBF process development using a modulated point melting method, post-AM hot isostatic pressing (HIP) treatment, destructive and non-destructive evaluation, microstructure control, and in-process monitoring. It was found that the modulated point melting method reduces cleavage cracking and crack nucleation points while elevated temperature HIP treatment improves the repeatability of the tensile behaviour, while mechanically healing process induced defects like solid-state cracks and nanopores.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"45 ","pages":"Article 102011"},"PeriodicalIF":2.7,"publicationDate":"2025-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145321266","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}
Pub Date : 2025-10-17DOI: 10.1016/j.nme.2025.102005
Naoya Odaira , Katsuaki Kodama , Daisuke Ito , Yasushi Saito , Joseph Don Parker , Takenao Shinohara
Lead-bismuth eutectic has emerged as a promising candidate for liquid metal coolant for Gen-IV nuclear reactors. Lead-bismuth eutectic is a unique material that expands gradually within the solid state. It may induce pipe deformation or rupture if it solidifies in a pipe or a container. In this study, the strain distributions of lead–bismuth eutectic in stainless-steel cups were evaluated using wavelength-resolved neutron imaging method. The wettability-improved case exhibited significantly larger compressive strain than in the others. The adhesion between lead–bismuth eutectic and the inner surface of the cup was a critical issue in the present study.
{"title":"Analysis of strain distribution of lead–bismuth eutectic inside a stainless steel cup by wavelength-resolved neutron imaging","authors":"Naoya Odaira , Katsuaki Kodama , Daisuke Ito , Yasushi Saito , Joseph Don Parker , Takenao Shinohara","doi":"10.1016/j.nme.2025.102005","DOIUrl":"10.1016/j.nme.2025.102005","url":null,"abstract":"<div><div>Lead-bismuth eutectic has emerged as a promising candidate for liquid metal coolant for Gen-IV nuclear reactors. Lead-bismuth eutectic is a unique material that expands gradually within the solid state. It may induce pipe deformation or rupture if it solidifies in a pipe or a container. In this study, the strain distributions of lead–bismuth eutectic in stainless-steel cups were evaluated using wavelength-resolved neutron imaging method. The wettability-improved case exhibited significantly larger compressive strain than in the others. The adhesion between lead–bismuth eutectic and the inner surface of the cup was a critical issue in the present study.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"45 ","pages":"Article 102005"},"PeriodicalIF":2.7,"publicationDate":"2025-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145362924","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}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号