Pub Date : 2026-03-01Epub Date: 2026-01-09DOI: 10.1016/j.nme.2026.102059
C. Kawan , S. Brezinsek , E. Wüst , T. Dittmar , T. Schwarz-Selinger , M. Rasinski , S. Möller , L. Gao , Ch. Linsmeier
<div><div>Tungsten (W) is the most promising plasma-facing material candidate for future deuterium–tritium (D–T) fusion reactors due to its favorable properties, such as low sputtering yield, low chemical reactivity, high melting point, and low intrinsic fuel retention. However, highly energetic neutrons from DT fusion reactions can cause displacement damage in the W lattice and enhance fuel retention. This affects the tritium cycle requirements and nuclear safety, as a tritium inventory builds up in the vessel. Therefore, diagnostics are required to quantify the D and T content in-situ in the plasma-facing and structural materials. Laser-induced Ablation Quadrupole Mass Spectrometry (LIA-QMS) is a promising method for quantifying fuel content with good spatial and depth resolution. LIA-QMS can be simultaneously applied with Laser-induced Breakdown Spectroscopy (LIBS). Combining both techniques provides the high depth resolution of LIBS with the quantification capabilities of LIA-QMS. This study compares D depth profiles recorded with pico-second LIA-QMS with Nuclear Reaction Analysis (NRA) with <span><math><msup><mrow></mrow><mrow><mn>3</mn></mrow></msup></math></span>He beam on a displacement-damaged W sample. The comparison reveals the depth profiling capabilities, strengths, and weaknesses of LIA-QMS using picosecond lasers. A set of similarly self-damaged (10.8 MeV W<span><math><msup><mrow></mrow><mrow><mn>3</mn><mo>+</mo></mrow></msup></math></span> irradiated) ITER-grade W samples from PLANSEE was gently loaded with D in a low-temperature plasma at 370 K. The D concentration was varied by subsequent annealing of the samples at different temperatures in a vacuum after the D decoration. The ratio between D<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> and HD, both contributing to the total D content, increases from 1:1 to 1:5, starting at the surface and extending to <span><math><mrow><mn>4</mn><mspace></mspace><mi>μ</mi><mi>m</mi></mrow></math></span>, with increasing depth. LIA-QMS shows a similarly high sensitivity (<span><math><mo><</mo></math></span>0.05 at<span><math><mtext>%</mtext></math></span> D at a 15 nm average ablation rate (AAR)) as NRA (around 150-400 nm resolution). ps-LIA-QMS can be calibrated via a known amount of reference gas injections and deviates from the NRA results by a factor of 1.7 across all samples, which also includes non-volatile species. The laser-induced crater surface stays relatively flat for up to <span><math><mrow><mn>4</mn><mspace></mspace><mi>μ</mi><mi>m</mi></mrow></math></span> until surface structures start dominating the crater’s surface under the given laser parameters. <span><math><mi>μ</mi></math></span>-NRA in and around the craters shows complete removal of D inside the laser crater. Thermal effects due to the ps-pulses within the crater floor are indicated, but could not be quantified yet. In conclusion, this study shows a good agreement between ps-LIA-QMS, a p
{"title":"Depth-resolved deuterium retention profiles in displacement-damaged tungsten measured via picosecond-laser-induced ablation quadrupole mass spectrometry","authors":"C. Kawan , S. Brezinsek , E. Wüst , T. Dittmar , T. Schwarz-Selinger , M. Rasinski , S. Möller , L. Gao , Ch. Linsmeier","doi":"10.1016/j.nme.2026.102059","DOIUrl":"10.1016/j.nme.2026.102059","url":null,"abstract":"<div><div>Tungsten (W) is the most promising plasma-facing material candidate for future deuterium–tritium (D–T) fusion reactors due to its favorable properties, such as low sputtering yield, low chemical reactivity, high melting point, and low intrinsic fuel retention. However, highly energetic neutrons from DT fusion reactions can cause displacement damage in the W lattice and enhance fuel retention. This affects the tritium cycle requirements and nuclear safety, as a tritium inventory builds up in the vessel. Therefore, diagnostics are required to quantify the D and T content in-situ in the plasma-facing and structural materials. Laser-induced Ablation Quadrupole Mass Spectrometry (LIA-QMS) is a promising method for quantifying fuel content with good spatial and depth resolution. LIA-QMS can be simultaneously applied with Laser-induced Breakdown Spectroscopy (LIBS). Combining both techniques provides the high depth resolution of LIBS with the quantification capabilities of LIA-QMS. This study compares D depth profiles recorded with pico-second LIA-QMS with Nuclear Reaction Analysis (NRA) with <span><math><msup><mrow></mrow><mrow><mn>3</mn></mrow></msup></math></span>He beam on a displacement-damaged W sample. The comparison reveals the depth profiling capabilities, strengths, and weaknesses of LIA-QMS using picosecond lasers. A set of similarly self-damaged (10.8 MeV W<span><math><msup><mrow></mrow><mrow><mn>3</mn><mo>+</mo></mrow></msup></math></span> irradiated) ITER-grade W samples from PLANSEE was gently loaded with D in a low-temperature plasma at 370 K. The D concentration was varied by subsequent annealing of the samples at different temperatures in a vacuum after the D decoration. The ratio between D<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> and HD, both contributing to the total D content, increases from 1:1 to 1:5, starting at the surface and extending to <span><math><mrow><mn>4</mn><mspace></mspace><mi>μ</mi><mi>m</mi></mrow></math></span>, with increasing depth. LIA-QMS shows a similarly high sensitivity (<span><math><mo><</mo></math></span>0.05 at<span><math><mtext>%</mtext></math></span> D at a 15 nm average ablation rate (AAR)) as NRA (around 150-400 nm resolution). ps-LIA-QMS can be calibrated via a known amount of reference gas injections and deviates from the NRA results by a factor of 1.7 across all samples, which also includes non-volatile species. The laser-induced crater surface stays relatively flat for up to <span><math><mrow><mn>4</mn><mspace></mspace><mi>μ</mi><mi>m</mi></mrow></math></span> until surface structures start dominating the crater’s surface under the given laser parameters. <span><math><mi>μ</mi></math></span>-NRA in and around the craters shows complete removal of D inside the laser crater. Thermal effects due to the ps-pulses within the crater floor are indicated, but could not be quantified yet. In conclusion, this study shows a good agreement between ps-LIA-QMS, a p","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"46 ","pages":"Article 102059"},"PeriodicalIF":2.7,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145977400","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 : 2026-03-01Epub Date: 2026-02-02DOI: 10.1016/j.nme.2026.102079
Vladimir Chakin, Carsten Bonnekoh, Ramil Gaisin, Rainer Ziegler, Michael Duerrschnabel, Michael Klimenkov, Bronislava Gorr, Michael Rieth
The reduced activation ferritic-martensitic (RAFM) EUROFER97-3 steel of two heat treatments (EUROFER97-3_1100/700 and EUROFER97-3_980/780) after irradiation in the BOR-60 fast reactor at temperatures of 330 °C and 540 °C, with damage doses ranging from 21.6 to 22.8 dpa showed big differences in the Charpy impact properties depending on the irradiation temperature. Significant drop in the upper shelf energy (USE) and shift of the ductile–brittle transition temperature (DBTT) occurred after irradiation at 330 °C. However, irradiation at 540 °C resulted in only minor changes in the USE and DBTT compared to the unirradiated reference state. Probably, these changes are attributed of the formation of radiation-induced defects and evolution in the phase structure.
{"title":"Charpy impact properties of EUROFER97-3 after neutron irradiation at 330 °C and 540 °C to damage doses of 21–23 dpa","authors":"Vladimir Chakin, Carsten Bonnekoh, Ramil Gaisin, Rainer Ziegler, Michael Duerrschnabel, Michael Klimenkov, Bronislava Gorr, Michael Rieth","doi":"10.1016/j.nme.2026.102079","DOIUrl":"10.1016/j.nme.2026.102079","url":null,"abstract":"<div><div>The reduced activation ferritic-martensitic (RAFM) EUROFER97-3 steel of two heat treatments (EUROFER97-3_1100/700 and EUROFER97-3_980/780) after irradiation in the BOR-60 fast reactor at temperatures of 330 °C and 540 °C, with damage doses ranging from 21.6 to 22.8 dpa showed big differences in the Charpy impact properties depending on the irradiation temperature. Significant drop in the upper shelf energy (USE) and shift of the ductile–brittle transition temperature (DBTT) occurred after irradiation at 330 °C. However, irradiation at 540 °C resulted in only minor changes in the USE and DBTT compared to the unirradiated reference state. Probably, these changes are attributed of the formation of radiation-induced defects and evolution in the phase structure.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"46 ","pages":"Article 102079"},"PeriodicalIF":2.7,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146173716","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 : 2026-03-01Epub Date: 2026-03-03DOI: 10.1016/j.nme.2026.102095
Sangeun Kim , Hyung-Ha Jin , Chang-hoon Lee , Sanghoon Noh , Sungjin Kwon , Dong Won Lee , Chansun Shin
In fusion-relevant environments where transmutation helium accumulates, He bubble formation can become a critical damage mechanism in reduced-activation ferritic/martensitic (RAFM) steels because it drives swelling and can degrade mechanical performance. Swelling is often assessed indirectly from surface-step height measurements and nanoindentation mapping, yet their quantitative relationship to the underlying bubble population remains unclear. Here, He bubbles in K-RAFM steels and a Eurofer97-like reference steel were quantified by cross-sectional TEM after 160 keV He implantation and post-irradiation annealing (PIA) at 300–500 °C. Bubble size distributions, number densities, and bubble-volume-fraction-based swelling were evaluated and directly compared with step-height- and hardness-based metrics. Bubble nucleation was most evident at 300–400 °C through an increase in number density, whereas pronounced coarsening at 500 °C led to a sharp increase in swelling. Step height reproduced the temperature-dependent swelling trend, while the nanoindentation hardening response was more closely linked to bubble number density than to bubble size. In addition, sequential H/He implantation revealed a clear He–H synergy, with a stronger enhancement of bubble density and swelling when H was implanted after He (He + H) than in the reverse order (H + He).
{"title":"Quantifying helium-bubble swelling in RAFM steels using TEM and the surface-step method","authors":"Sangeun Kim , Hyung-Ha Jin , Chang-hoon Lee , Sanghoon Noh , Sungjin Kwon , Dong Won Lee , Chansun Shin","doi":"10.1016/j.nme.2026.102095","DOIUrl":"10.1016/j.nme.2026.102095","url":null,"abstract":"<div><div>In fusion-relevant environments where transmutation helium accumulates, He bubble formation can become a critical damage mechanism in reduced-activation ferritic/martensitic (RAFM) steels because it drives swelling and can degrade mechanical performance. Swelling is often assessed indirectly from surface-step height measurements and nanoindentation mapping, yet their quantitative relationship to the underlying bubble population remains unclear. Here, He bubbles in K-RAFM steels and a Eurofer97-like reference steel were quantified by cross-sectional TEM after 160 keV He implantation and post-irradiation annealing (PIA) at 300–500 °C. Bubble size distributions, number densities, and bubble-volume-fraction-based swelling were evaluated and directly compared with step-height- and hardness-based metrics. Bubble nucleation was most evident at 300–400 °C through an increase in number density, whereas pronounced coarsening at 500 °C led to a sharp increase in swelling. Step height reproduced the temperature-dependent swelling trend, while the nanoindentation hardening response was more closely linked to bubble number density than to bubble size. In addition, sequential H/He implantation revealed a clear He–H synergy, with a stronger enhancement of bubble density and swelling when H was implanted after He (He + H) than in the reverse order (H + He).</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"46 ","pages":"Article 102095"},"PeriodicalIF":2.7,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147420888","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 : 2026-03-01Epub Date: 2025-12-11DOI: 10.1016/j.nme.2025.102044
Qilong Cao , Fangqing Qian , Xiaolin Li , Panpan Wang , He Tong , Yange Zhang , Yichun Xu , Xianping Wang , C.S. Liu , Xiang-Yan Li
Grain boundaries (GBs) serve as critical microstructural features in determining the radiation resistance of nanocrystalline metals through their capacity to absorb radiation-induced defects, particularly self-interstitial atoms (SIAs) and vacancies (Vs). Nevertheless, the fundamental mechanism governing SIA dynamics near GBs that dominate defect–GB interactions remain inadequately elucidated. This knowledge gap is primarily due to the fact that the time scale of SIA diffusion and its segregation towards GBs is significantly smaller than that of other events, leading to its preferential segregation to GBs and decoupling from other defects. In this study, we employ combined molecular statics and dynamics simulations to systematically investigate the atomic-scale behavior of SIA and its cluster (SIAn) states near GBs in three body-centered cubic metals (tungsten, molybdenum and iron), while concurrently exploring potential V annihilation mechanisms associated with these processes. We propose a “self-blocking” mechanism governing the behavior of the SIAn near GBs at low temperatures. As accumulated SIAns progressively occupy GB trapping sites, subsequent incoming clusters experience spatial confinement within the near-boundary region. These constrained SIAns exhibit intermediate energy states between bulk configuration states and fully GB-trapped states. Crucially, the partially constrained SIAns demonstrate two distinctive features of an enhanced V annihilation volume exceeding that of GB-trapped clusters by several times (attributed to their preserved bulk-like atomic configurations) and long-range repulsive interactions with bulk SIAs (potentially modifying defect-trapping dynamics of GBs). This self-blocking phenomenon implies both a saturation threshold for GB defect absorption capacity and an extended boundary zone facilitating V–SIA recombination. The spatially confined annihilation pathway near GBs provides a potential channel for eliminating bulk defects at low temperatures, offering new insights into the atomic-scale self-healing processes in nanocrystalline materials.
{"title":"Self-blocking driven interstitial confinement at metallic grain boundaries","authors":"Qilong Cao , Fangqing Qian , Xiaolin Li , Panpan Wang , He Tong , Yange Zhang , Yichun Xu , Xianping Wang , C.S. Liu , Xiang-Yan Li","doi":"10.1016/j.nme.2025.102044","DOIUrl":"10.1016/j.nme.2025.102044","url":null,"abstract":"<div><div>Grain boundaries (GBs) serve as critical microstructural features in determining the radiation resistance of nanocrystalline metals through their capacity to absorb radiation-induced defects, particularly self-interstitial atoms (SIAs) and vacancies (Vs). Nevertheless, the fundamental mechanism governing SIA dynamics near GBs that dominate defect–GB interactions remain inadequately elucidated. This knowledge gap is primarily due to the fact that the time scale of SIA diffusion and its segregation towards GBs is significantly smaller than that of other events, leading to its preferential segregation to GBs and decoupling from other defects. In this study, we employ combined molecular statics and dynamics simulations to systematically investigate the atomic-scale behavior of SIA and its cluster (SIA<sub>n</sub>) states near GBs in three body-centered cubic metals (tungsten, molybdenum and iron), while concurrently exploring potential V annihilation mechanisms associated with these processes. We propose a “self-blocking” mechanism governing the behavior of the SIA<sub>n</sub> near GBs at low temperatures. As accumulated SIA<sub>n</sub>s progressively occupy GB trapping sites, subsequent incoming clusters experience spatial confinement within the near-boundary region. These constrained SIA<sub>n</sub>s exhibit intermediate energy states between bulk configuration states and fully GB-trapped states. Crucially, the partially constrained SIA<sub>n</sub>s demonstrate two distinctive features of an enhanced V annihilation volume exceeding that of GB-trapped clusters by several times (attributed to their preserved bulk-like atomic configurations) and long-range repulsive interactions with bulk SIAs (potentially modifying defect-trapping dynamics of GBs). This self-blocking phenomenon implies both a saturation threshold for GB defect absorption capacity and an extended boundary zone facilitating V–SIA recombination. The spatially confined annihilation pathway near GBs provides a potential channel for eliminating bulk defects at low temperatures, offering new insights into the atomic-scale self-healing processes in nanocrystalline materials.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"46 ","pages":"Article 102044"},"PeriodicalIF":2.7,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145738857","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 : 2026-03-01Epub Date: 2026-02-19DOI: 10.1016/j.nme.2026.102089
M. De Angeli , P. Tolias , S. Ratynskaia , D. Ripamonti , M. Iafrati , G. Maddaluno , G. Daminelli , E. Fortuna-Zalesna
Runaway electron (RE) interaction with plasma-facing components (PFCs) has been documented to lead to deep volumetric melting and thermal shock driven material explosions followed by extensive wall cratering. This work reports a post-mortem FTU investigation that covers the primary localized RE-induced damage directly caused by beams striking poloidal or toroidal molybdenum (Mo)-based limiters and the subsequent secondary non-localized RE-induced damage inflicted on nearby limiter tiles by the mechanical impact of fast up to km/s solid debris violently ejected during the direct RE-PFC interaction. Early indications on the resilience of tin liquid limiters to RE incidence are also presented.
{"title":"Primary and secondary metallic PFC damage induced by runaway electron dissipation in FTU","authors":"M. De Angeli , P. Tolias , S. Ratynskaia , D. Ripamonti , M. Iafrati , G. Maddaluno , G. Daminelli , E. Fortuna-Zalesna","doi":"10.1016/j.nme.2026.102089","DOIUrl":"10.1016/j.nme.2026.102089","url":null,"abstract":"<div><div>Runaway electron (RE) interaction with plasma-facing components (PFCs) has been documented to lead to deep volumetric melting and thermal shock driven material explosions followed by extensive wall cratering. This work reports a post-mortem FTU investigation that covers the primary localized RE-induced damage directly caused by beams striking poloidal or toroidal molybdenum (Mo)-based limiters and the subsequent secondary non-localized RE-induced damage inflicted on nearby limiter tiles by the mechanical impact of fast up to <span><math><mrow><mo>∼</mo><mn>1</mn></mrow></math></span> <!--> <!-->km/s solid debris violently ejected during the direct RE-PFC interaction. Early indications on the resilience of tin liquid limiters to RE incidence are also presented.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"46 ","pages":"Article 102089"},"PeriodicalIF":2.7,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147420343","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 : 2026-03-01Epub Date: 2026-01-03DOI: 10.1016/j.nme.2025.102056
Nathan Nelson , Céline Martin , Cécile Arnas , Andrea Campos , Elodie Bernard , Chijin Xiao , Lénaïc Couëdel , West Team
Dust particles deposited during the first phase of operation of the WEST tokamak were collected and analysed from substrates positioned at four distinct poloidal locations along the inner wall. Among various particle types composed of materials present in the vacuum vessel, previously unreported tungsten molten splashes exhibiting highly distinctive “stethoscope-like” morphologies were discovered. These unusual tungsten particles were found in large numbers exclusively on substrates located closest to the lower divertor. They display a well-defined log-normal size distribution, with average lengths ranging from 0.75 to 1.5 µm, and a clear angular alignment pointing predominantly away from the divertor. This directional distribution provides compelling evidence that they were ejected from the lower divertor region. Additionally, more conventional tungsten ellipsoidal particles were identified across all four poloidal positions. These ellipsoids were most abundant near the divertor and exhibited progressively more elongated shapes and less distinct alignment patterns with increasing distance, suggesting a common origin but different transport histories. Their size distributions are also log-normal, with average diameters between 100 and 200 nm. The characteristics of both particle types (distribution, size scaling, and directionality) suggest a common origin in molten tungsten droplets expelled from the lower divertor, most likely as a result of arcing events.
{"title":"Dust deposition on plasma-facing substrates extracted from the WEST Tokamak","authors":"Nathan Nelson , Céline Martin , Cécile Arnas , Andrea Campos , Elodie Bernard , Chijin Xiao , Lénaïc Couëdel , West Team","doi":"10.1016/j.nme.2025.102056","DOIUrl":"10.1016/j.nme.2025.102056","url":null,"abstract":"<div><div>Dust particles deposited during the first phase of operation of the WEST tokamak were collected and analysed from substrates positioned at four distinct poloidal locations along the inner wall. Among various particle types composed of materials present in the vacuum vessel, previously unreported tungsten molten splashes exhibiting highly distinctive “stethoscope-like” morphologies were discovered. These unusual tungsten particles were found in large numbers exclusively on substrates located closest to the lower divertor. They display a well-defined log-normal size distribution, with average lengths ranging from 0.75 to 1.5 µm, and a clear angular alignment pointing predominantly away from the divertor. This directional distribution provides compelling evidence that they were ejected from the lower divertor region. Additionally, more conventional tungsten ellipsoidal particles were identified across all four poloidal positions. These ellipsoids were most abundant near the divertor and exhibited progressively more elongated shapes and less distinct alignment patterns with increasing distance, suggesting a common origin but different transport histories. Their size distributions are also log-normal, with average diameters between 100 and 200 nm. The characteristics of both particle types (distribution, size scaling, and directionality) suggest a common origin in molten tungsten droplets expelled from the lower divertor, most likely as a result of arcing events.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"46 ","pages":"Article 102056"},"PeriodicalIF":2.7,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145926749","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 : 2026-03-01Epub Date: 2026-01-14DOI: 10.1016/j.nme.2026.102064
Jonathan Coburn , Florian Effenberg , Mary Alice Cusentino , Chase Hargrove , Mykola Ialovega , Maria Morbey , Lauren Nuckols , Žana Popović , Zachary Bergstrom , Shawn Zamperini , Tyler Abrams , Dmitry Rudakov , Shota Abe , Shane Evans , Tatsuya Hinoki , Ryan Hood , Eric Lang , Charlie Lasnier , Ulises Losada , Claudio Marini , Weicheng Zhong
Characterization and testing of advanced plasma-facing materials (PFMs) for Fusion Pilot Plants (FPP) is being conducted at the DIII-D National Fusion Facility through the ongoing two-year FPP Candidate Materials Thrust. Year one tested 17 novel materials utilizing the Divertor Materials Evaluation System (DiMES), with samples analyzed pre- and post-experiment via SEM, EDS, and confocal microscopy. Repeatable reference discharges were developed to ensure uniformity between experiments, including a new strike-point rastering scenario to provide more uniform heat/particle flux across DiMES during ELMing H-mode discharges. Various sample geometries and temperatures were used to achieve FPP-relevant conditions, including samples angled 10° towards the incident plasma flux and pre-heating up to 500 °C.
The first exposure of liquid lithium (Li) capillary porous structures in a tokamak demonstrated uniform emission of Li vapor and suppression of Li droplets in H-mode when preheated to 350 °C. Dispersoid-strengthened W with 1 wt% TaC, TiC, and ZrC exposed to H-mode showed cracking and dispersoid ejection for all varieties except TiC, providing a clear down-selection. Ultra-high temperature ceramic materials TiB2 and ZrB2 showed minimal degradation under L-mode exposure. Silicon carbide (SiC) fiber composites showed arcing along edges, while CVD SiC remained pristine. Atmospheric plasma-sprayed W and SiC coatings endured H-mode exposure without macroscopic delamination; SiC exhibited granular ejection, while W showed increased outgassing. Additional W-based alloys were stress tested in H-mode, including Ni-based W heavy alloys, WfSiCf/W composites, W multi-principle element alloys, and functionally-graded W/SiC, to varying degrees of success.
{"title":"Overview of advanced plasma-facing materials testing for Fusion Pilot Plants at DIII-D","authors":"Jonathan Coburn , Florian Effenberg , Mary Alice Cusentino , Chase Hargrove , Mykola Ialovega , Maria Morbey , Lauren Nuckols , Žana Popović , Zachary Bergstrom , Shawn Zamperini , Tyler Abrams , Dmitry Rudakov , Shota Abe , Shane Evans , Tatsuya Hinoki , Ryan Hood , Eric Lang , Charlie Lasnier , Ulises Losada , Claudio Marini , Weicheng Zhong","doi":"10.1016/j.nme.2026.102064","DOIUrl":"10.1016/j.nme.2026.102064","url":null,"abstract":"<div><div>Characterization and testing of advanced plasma-facing materials (PFMs) for Fusion Pilot Plants (FPP) is being conducted at the DIII-D National Fusion Facility through the ongoing two-year FPP Candidate Materials Thrust. Year one tested 17 novel materials utilizing the Divertor Materials Evaluation System (DiMES), with samples analyzed pre- and post-experiment via SEM, EDS, and confocal microscopy. Repeatable reference discharges were developed to ensure uniformity between experiments, including a new strike-point rastering scenario to provide more uniform heat/particle flux across DiMES during ELMing H-mode discharges. Various sample geometries and temperatures were used to achieve FPP-relevant conditions, including samples angled 10° towards the incident plasma flux and pre-heating up to 500<!--> <!-->°C.</div><div>The first exposure of liquid lithium (Li) capillary porous structures in a tokamak demonstrated uniform emission of Li vapor and suppression of Li droplets in H-mode when preheated to 350 °C. Dispersoid-strengthened W with 1 wt% TaC, TiC, and ZrC exposed to H-mode showed cracking and dispersoid ejection for all varieties except TiC, providing a clear down-selection. Ultra-high temperature ceramic materials TiB<sub>2</sub> and ZrB<sub>2</sub> showed minimal degradation under L-mode exposure. Silicon carbide (SiC) fiber composites showed arcing along edges, while CVD SiC remained pristine. Atmospheric plasma-sprayed W and SiC coatings endured H-mode exposure without macroscopic delamination; SiC exhibited granular ejection, while W showed increased outgassing. Additional W-based alloys were stress tested in H-mode, including Ni-based W heavy alloys, W<sub>f</sub>SiC<sub>f</sub>/W composites, W multi-principle element alloys, and functionally-graded W/SiC, to varying degrees of success.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"46 ","pages":"Article 102064"},"PeriodicalIF":2.7,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146077940","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 : 2026-03-01Epub Date: 2026-01-27DOI: 10.1016/j.nme.2026.102072
Alex Aimetta , Nicolò Abrate , Marco Caravello , Sandra Dulla , Antonio Froio , Mattia Massone
In the framework of the modeling of fusion reactors with deterministic neutronic codes, the choice of an appropriate energy grid for the generation of the multigroup nuclear properties is essential. In this work, a Genetic Algorithm is employed to optimize the energy grid employed in the nemoFoam multiphysics code to reproduce the results provided by the Monte Carlo code Serpent in terms of neutron flux, neutron power deposition and Tritium Breeding Ratio for the Affordable, Robust and Compact (ARC) fusion reactor. Different runs of the Genetic Algorithm are performed, with the aim of optimizing not only the quantities of interest separately, but also trying to combine them thanks to the definition of appropriate fitness functions. The optimization is performed starting from a pre-defined 86 groups energy grid, over which the nuclear properties and the reference quantities are evaluated with Serpent. The results show that it is not straightforward to optimize at the same time the energy grid for different quantities and that, in general, coarse energy grids are able to provide good results in nemoFoam for what concerns the ARC reactor, allowing to alleviate the computational burden of the neutronic evaluation too.
{"title":"A genetic algorithm to optimize the multi-group structure for the neutronic analyses of the ARC fusion reactor","authors":"Alex Aimetta , Nicolò Abrate , Marco Caravello , Sandra Dulla , Antonio Froio , Mattia Massone","doi":"10.1016/j.nme.2026.102072","DOIUrl":"10.1016/j.nme.2026.102072","url":null,"abstract":"<div><div>In the framework of the modeling of fusion reactors with deterministic neutronic codes, the choice of an appropriate energy grid for the generation of the multigroup nuclear properties is essential. In this work, a Genetic Algorithm is employed to optimize the energy grid employed in the nemoFoam multiphysics code to reproduce the results provided by the Monte Carlo code Serpent in terms of neutron flux, neutron power deposition and Tritium Breeding Ratio for the Affordable, Robust and Compact (ARC) fusion reactor. Different runs of the Genetic Algorithm are performed, with the aim of optimizing not only the quantities of interest separately, but also trying to combine them thanks to the definition of appropriate fitness functions. The optimization is performed starting from a pre-defined 86 groups energy grid, over which the nuclear properties and the reference quantities are evaluated with Serpent. The results show that it is not straightforward to optimize at the same time the energy grid for different quantities and that, in general, coarse energy grids are able to provide good results in nemoFoam for what concerns the ARC reactor, allowing to alleviate the computational burden of the neutronic evaluation too.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"46 ","pages":"Article 102072"},"PeriodicalIF":2.7,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146173168","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 : 2026-03-01Epub Date: 2025-12-13DOI: 10.1016/j.nme.2025.102048
L. Vignitchouk, JET Contributors
Multiphase Navier–Stokes simulations of castellated beryllium plates exposed to JET-like disruption plasma loads are performed to investigate melt transport in the vicinity of gaps and the formation of re-solidified bridges between adjacent castellation blocks. It is found that two-dimensional computations are able to predict whether bridging occurs and that they agree with experimental data in terms of characteristic melt infiltration depths and global material transport along the surface. However, three-dimensional set-ups appear to be necessary when estimates of the damaged component’s surface morphology are sought in cases where bridging does not occur. Comparisons with simplified shallow-water models confirm that such models are applicable to scenarios in which bridges have already been formed, although they tend to overestimate the net melt displacement.
{"title":"Simulations of beryllium castellation gap bridging during vertical displacement events","authors":"L. Vignitchouk, JET Contributors","doi":"10.1016/j.nme.2025.102048","DOIUrl":"10.1016/j.nme.2025.102048","url":null,"abstract":"<div><div>Multiphase Navier–Stokes simulations of castellated beryllium plates exposed to JET-like disruption plasma loads are performed to investigate melt transport in the vicinity of gaps and the formation of re-solidified bridges between adjacent castellation blocks. It is found that two-dimensional computations are able to predict whether bridging occurs and that they agree with experimental data in terms of characteristic melt infiltration depths and global material transport along the surface. However, three-dimensional set-ups appear to be necessary when estimates of the damaged component’s surface morphology are sought in cases where bridging does not occur. Comparisons with simplified shallow-water models confirm that such models are applicable to scenarios in which bridges have already been formed, although they tend to overestimate the net melt displacement.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"46 ","pages":"Article 102048"},"PeriodicalIF":2.7,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145791719","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 : 2026-03-01Epub Date: 2026-01-17DOI: 10.1016/j.nme.2026.102065
Indrek Jõgi , Peeter Paris , Kaarel Piip , Jordy Vernimmen , Beata Tyburska-Pueschel , Sven Lange , Taivo Jõgiaas , Matteo Passoni , David Dellasega , Gabriele Alberti , Hennie van der Meiden
The present study investigated the effect of D2-N2 (7%) plasma exposure in Magnum-PSI on the D retention and chemical and mechanical properties of a porous W-O (p-W-O) coating. The variation of the chemical composition, crystalline phase and mechanical properties along the sample surface were determined by Nuclear Reaction Analysis (NRA), Rutherford Backscattering Spectroscopy (RBS), nanoindentation and Raman spectroscopy. These changes were compared to the Laser-Induced Breakdown Spectroscopy (LIBS) measurements. LIBS depth profiles of W and Mo were consistent with the profiles determined by NRA and RBS, showing a W-O layer, a thin W adhesion layer and a Mo substrate. Typically, the high D intensity was determined only during the first LIBS laser shot on a measurement spot, while the spatial distribution of D intensity determined by LIBS along the coating surface followed the D concentration determined by NRA. According to the Raman spectra, the investigated p-W-O coating corresponded to nanograins of W-O and the phase composition was relatively uniform along the coating surface. The elastic modulus of p-W-O coating was considerably lower than the modulus of Mo coating or bulk W coating and corresponded to the values found in other studies carried out with W-O mixtures. The elastic modulus of p-W-O coating decreased towards the edge of the coating. The study revealed that the modulus and the background intensity of the LIBS spectra had a negative correlation, suggesting that LIBS may be a suitable method for the estimation of the stiffness of tungsten co-deposits as a similar correlation is shown for other types of W coatings.
{"title":"Modification of chemical and mechanical properties of p-W-O coating after Magnum-PSI D2-N2 plasma exposure and its consequences for the analysis of LIBS spectra","authors":"Indrek Jõgi , Peeter Paris , Kaarel Piip , Jordy Vernimmen , Beata Tyburska-Pueschel , Sven Lange , Taivo Jõgiaas , Matteo Passoni , David Dellasega , Gabriele Alberti , Hennie van der Meiden","doi":"10.1016/j.nme.2026.102065","DOIUrl":"10.1016/j.nme.2026.102065","url":null,"abstract":"<div><div>The present study investigated the effect of D<sub>2</sub>-N<sub>2</sub> (7%) plasma exposure in Magnum-PSI on the D retention and chemical and mechanical properties of a porous W-O (p-W-O) coating. The variation of the chemical composition, crystalline phase and mechanical properties along the sample surface were determined by Nuclear Reaction Analysis (NRA), Rutherford Backscattering Spectroscopy (RBS), nanoindentation and Raman spectroscopy. These changes were compared to the Laser-Induced Breakdown Spectroscopy (LIBS) measurements. LIBS depth profiles of W and Mo were consistent with the profiles determined by NRA and RBS, showing a W-O layer, a thin W adhesion layer and a Mo substrate. Typically, the high D intensity was determined only during the first LIBS laser shot on a measurement spot, while the spatial distribution of D intensity determined by LIBS along the coating surface followed the D concentration determined by NRA. According to the Raman spectra, the investigated p-W-O coating corresponded to nanograins of W-O and the phase composition was relatively uniform along the coating surface. The elastic modulus of p-W-O coating was considerably lower than the modulus of Mo coating or bulk W coating and corresponded to the values found in other studies carried out with W-O mixtures. The elastic modulus of p-W-O coating decreased towards the edge of the coating. The study revealed that the modulus and the background intensity of the LIBS spectra had a negative correlation, suggesting that LIBS may be a suitable method for the estimation of the stiffness of tungsten co-deposits as a similar correlation is shown for other types of W coatings.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"46 ","pages":"Article 102065"},"PeriodicalIF":2.7,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146022935","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}
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