Pub Date : 2026-01-26DOI: 10.1016/j.nme.2026.102071
Sören Möller , Christoph Kawan , Marcin Rasinski , Gennady Sergienko , Arkadi Kreter , Eduard Grigore , Erik Wüst , Khoirul Faiq Muzakka , Sebastijan Brezinsek
Laser based surface composition analysis methods are used as an in-situ tool for material analysis in nuclear fusion reactors. The methods investigated here ablate material from the surface and analyse the surface composition through the released particles. A quantification requires the calibration of the detection efficiency of the released material and its relation to the affected surface area and depth. Only with this quantification, the laser methods can provide quantitative data on hydrogen isotope retention and plasma-surface interaction.
In this work, we combine three high-resolution imaging techniques to provide a complete understanding of the surface structure and elemental composition using a ps-Laser ablating ∼5 µm of W. MeV ion-beam analysis (IBA), in particular with the latest developments regarding high-throughput IBA imaging provides insight into the deuterium content. This enables a new and unique experimental insight into five individual limitations of the deuterium depth resolution and accuracy limitations of laser ablation methods related to the matrix effect. The results enable precise calibration of laser methods and understanding of their limitations. In particular, the thermal desorption halo, the crater-floor depletion fraction, and the impact of crater edge effects are quantified. From sample effect, we see a relative uncertainty of ±9% and an absolute uncertainty of ±52%.
{"title":"Imaging analysis of ps laser induced ablation spectroscopy and mass spectrometry − deuterium depth resolution, removal fraction, and uncertainties","authors":"Sören Möller , Christoph Kawan , Marcin Rasinski , Gennady Sergienko , Arkadi Kreter , Eduard Grigore , Erik Wüst , Khoirul Faiq Muzakka , Sebastijan Brezinsek","doi":"10.1016/j.nme.2026.102071","DOIUrl":"10.1016/j.nme.2026.102071","url":null,"abstract":"<div><div>Laser based surface composition analysis methods are used as an in-situ tool for material analysis in nuclear fusion reactors. The methods investigated here ablate material from the surface and analyse the surface composition through the released particles. A quantification requires the calibration of the detection efficiency of the released material and its relation to the affected surface area and depth. Only with this quantification, the laser methods can provide quantitative data on hydrogen isotope retention and plasma-surface interaction.</div><div>In this work, we combine three high-resolution imaging techniques to provide a complete understanding of the surface structure and elemental composition using a ps-Laser ablating ∼5 µm of W. MeV ion-beam analysis (IBA), in particular with the latest developments regarding high-throughput IBA imaging provides insight into the deuterium content. This enables a new and unique experimental insight into five individual limitations of the deuterium depth resolution and accuracy limitations of laser ablation methods related to the matrix effect. The results enable precise calibration of laser methods and understanding of their limitations. In particular, the thermal desorption halo, the crater-floor depletion fraction, and the impact of crater edge effects are quantified. From sample effect, we see a relative uncertainty of ±9% and an absolute uncertainty of ±52%.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"46 ","pages":"Article 102071"},"PeriodicalIF":2.7,"publicationDate":"2026-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146173166","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}
For the evaluation of hydrogen isotope retention behavior for advanced plasma facing materials like W-Ta, W-Mo alloys and K-doped W, D2+ implantation with different incident energies of 1 keV and 3 keV was performed up to the fluence of 1x1022 D m−2. Thereafter D retention behavior was evaluated by thermal desorption spectroscopy (TDS) up to the temperature of 1173 K. 6 MeV Fe2+ irradiation was also performed to introduce the irradiation damage up to the damage level of 1 dpa, followed by the evaluation of D retention. In addition, positron annihilation spectroscopy (PAS) was performed to clarify the density and size of irradiation defects among these advanced W materials. The HIDT (Hydrogen Isotopes Diffusion and Trapping) simulation was applied to evaluate the activation energies of D trapping and their trap densities based exclusively on D2 desorption.
The results showed that no large D retention enhancement was found for W alloys, but the D trap density with higher trap energy was reduced. In especially, the formation of large voids was refrained and D trapping by small trap energy like mono-vacancy was the major D trapping sites for K-doped W. For W-Mo and W-Ta, the addition of minor element would occupy the irradiation defects leading to the refrain of D trapping with stable D trap energy.
{"title":"Comparison of D retention for advanced plasma facing materials by D ion implantation","authors":"Shingo Okumura , Yuzuka Hoshino , Ayumu Hayakawa , Kenshiro Miura , Fei Sun , Suguru Masuzaki , Makoto Oyaizu , Robert Kolasinski , Chase N. Taylor , Teppei Otsuka , Yuji Hatano , Masashi Shimada , Hao Yu , Ryuta Kasada , Akira Hasegawa , Yasuhisa Oya","doi":"10.1016/j.nme.2026.102069","DOIUrl":"10.1016/j.nme.2026.102069","url":null,"abstract":"<div><div>For the evaluation of hydrogen isotope retention behavior for advanced plasma facing materials like W-Ta, W-Mo alloys and K-doped W, D<sub>2</sub><sup>+</sup> implantation with different incident energies of 1 keV and 3 keV was performed up to the fluence of 1x10<sup>22</sup> D m<sup>−2</sup>. Thereafter D retention behavior was evaluated by thermal desorption spectroscopy (TDS) up to the temperature of 1173 K. 6 MeV Fe<sup>2+</sup> irradiation was also performed to introduce the irradiation damage up to the damage level of 1 dpa, followed by the evaluation of D retention. In addition, positron annihilation spectroscopy (PAS) was performed to clarify the density and size of irradiation defects among these advanced W materials. The HIDT (Hydrogen Isotopes Diffusion and Trapping) simulation was applied to evaluate the activation energies of D trapping and their trap densities based exclusively on D<sub>2</sub> desorption.</div><div>The results showed that no large D retention enhancement was found for W alloys, but the D trap density with higher trap energy was reduced. In especially, the formation of large voids was refrained and D trapping by small trap energy like mono-vacancy was the major D trapping sites for K-doped W. For W-Mo and W-Ta, the addition of minor element would occupy the irradiation defects leading to the refrain of D trapping with stable D trap energy.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"46 ","pages":"Article 102069"},"PeriodicalIF":2.7,"publicationDate":"2026-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146078031","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 : 2026-01-22DOI: 10.1016/j.nme.2026.102066
A. Huber , Ph. Andrew , G. Sergienko , J. Assmann , D. Castano , A. De Schepper , S. Friese , R. Greven , I. Ivashov , D. Kampf , Y. Krasikov , C.C. Klepper , H.T. Lambertz , Ph. Mertens , K. Mlynczak , G. Offermanns , B. Quinlan , K. Rasinska , M. Schrader , D. Van Staden , Ch. Linsmeier
This paper addresses the challenge of tritium inventory management in ITER and future fusion reactors, highlighting the importance of accurate tritium measurement and its spatial distribution within the vacuum vessel. Given ITER’s operational constraints, especially the limit on tritium retention, precise measurement is essential for both safety and regulatory compliance. To tackle these questions, the paper presents the T-monitor diagnostic system developed by Forschungszentrum Jülich, which uses Laser-Induced Desorption (LID) in combination with Diagnostic Residual Gas Analysis (DRGA) to measure hydrogen isotope concentrations on the surface of divertor tiles. The system integrates a high-power laser, advanced optical components, and a Fast Scanning Mirror Unit (FSMU) for accurate laser spot positioning with rapid response.
Designed to measure in situ tritium retention, the diagnostic provides high-resolution spatial mapping, vital for evaluating detritiation strategies. The laser heating process increases the divertor surface temperature to 1600 K within the laser spot, promoting hydrogen isotope desorption. Accurate measurements require the precise control of laser parameters, including pulse duration and spot size, with a target relative accuracy of 20%. The optical design includes both in-vessel and ex-vessel components, such as durable high-reflectivity mirrors made of gold and copper, selected not only for their infrared performance but also for their transmission of visible wavelengths for observation purposes. To protect optical components from contamination, a pneumatic shutter is used.
{"title":"Innovative laser-based methods for monitoring fuel retention in ITER","authors":"A. Huber , Ph. Andrew , G. Sergienko , J. Assmann , D. Castano , A. De Schepper , S. Friese , R. Greven , I. Ivashov , D. Kampf , Y. Krasikov , C.C. Klepper , H.T. Lambertz , Ph. Mertens , K. Mlynczak , G. Offermanns , B. Quinlan , K. Rasinska , M. Schrader , D. Van Staden , Ch. Linsmeier","doi":"10.1016/j.nme.2026.102066","DOIUrl":"10.1016/j.nme.2026.102066","url":null,"abstract":"<div><div>This paper addresses the challenge of tritium inventory management in ITER and future fusion reactors, highlighting the importance of accurate tritium measurement and its spatial distribution within the vacuum vessel. Given ITER’s operational constraints, especially the limit on tritium retention, precise measurement is essential for both safety and regulatory compliance. To tackle these questions, the paper presents the T-monitor diagnostic system developed by Forschungszentrum Jülich, which uses Laser-Induced Desorption (LID) in combination with Diagnostic Residual Gas Analysis (DRGA) to measure hydrogen isotope concentrations on the surface of divertor tiles. The system integrates a high-power laser, advanced optical components, and a Fast Scanning Mirror Unit (FSMU) for accurate laser spot positioning with rapid response.</div><div>Designed to measure <em>in situ</em> tritium retention, the diagnostic provides high-resolution spatial mapping, vital for evaluating detritiation strategies. The laser heating process increases the divertor surface temperature to 1600 K within the laser spot, promoting hydrogen isotope desorption. Accurate measurements require the precise control of laser parameters, including pulse duration and spot size, with a target relative accuracy of 20%. The optical design includes both in-vessel and ex-vessel components, such as durable high-reflectivity mirrors made of gold and copper, selected not only for their infrared performance but also for their transmission of visible wavelengths for observation purposes. To protect optical components from contamination, a pneumatic shutter is used.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"46 ","pages":"Article 102066"},"PeriodicalIF":2.7,"publicationDate":"2026-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146078032","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 : 2026-01-22DOI: 10.1016/j.nme.2026.102070
K. Krieger, V. Rohde, ASDEX Upgrade Team
Long Term Sample (LTS) holders installed at remote wall locations of ASDEX Upgrade (AUG) and equipped with silicon wafer witness samples are used to monitor the integral net deposition of boron by glow discharge boronisation (GDB). Deposited low-Z impurities (B, C) and deuterium are quantified by Nuclear Reaction Analysis. Isotopes are resolved by analysis of their characteristic peaks in the energy spectra of detected protons. For the analysis a fitting procedure, tailored to the expected species, has been implemented and calibrated against quantitatively characterised standard samples.
The analysis has been applied to LTS from recent AUG campaigns. The results revealed that only a small fraction of the total boron introduced during the campaign can be accounted for with the rest assumed to be exhausted as molecular compounds during the campaign and also during post-campaign flushing of the vessel with air.
{"title":"Quantification of deuterium and low-Z impurity deposition on long-term samples exposed in ASDEX Upgrade","authors":"K. Krieger, V. Rohde, ASDEX Upgrade Team","doi":"10.1016/j.nme.2026.102070","DOIUrl":"10.1016/j.nme.2026.102070","url":null,"abstract":"<div><div>Long Term Sample (LTS) holders installed at remote wall locations of ASDEX Upgrade (AUG) and equipped with silicon wafer witness samples are used to monitor the integral net deposition of boron by glow discharge boronisation (GDB). Deposited low-Z impurities (B, C) and deuterium are quantified by <span><math><mrow><msup><mrow></mrow><mrow><mn>3</mn></mrow></msup><mi>He</mi></mrow></math></span> Nuclear Reaction Analysis. Isotopes are resolved by analysis of their characteristic peaks in the energy spectra of detected protons. For the analysis a fitting procedure, tailored to the expected species, has been implemented and calibrated against quantitatively characterised standard samples.</div><div>The analysis has been applied to LTS from recent AUG campaigns. The results revealed that only a small fraction of the total boron introduced during the campaign can be accounted for with the rest assumed to be exhausted as molecular compounds during the campaign and also during post-campaign flushing of the vessel with air.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"46 ","pages":"Article 102070"},"PeriodicalIF":2.7,"publicationDate":"2026-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146023236","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 : 2026-01-19DOI: 10.1016/j.nme.2026.102063
R. Neu, C. Angioni, V. Bobkov, R. Dux, J. Hobirk, A. Kallenbach, K. Krieger, T. Pütterich, V. Rohde, K. Schmid
With the decision of ITER to start its operation with tungsten as plasma facing material also for the main chamber plasma facing components, the interest in the consequences of the use of W was strongly increased. Although many investigations had already been carried out in the all-W ASDEX Upgrade, EAST and WEST tokamak experiments, the ITER decision raised many new questions. To provide a robust foundation for addressing these questions, this paper reviews the tungsten related investigations carried out in ASDEX Upgrade over the last three decades in order to summarize the results achieved so far and to provide a comprehensive list of references for more detailed reading. Further to conclude from this material which results can be used directly for the full-W ITER, where further work is needed and possibly rewarding and which areas are difficult to be researched in AUG and other present-day devices.
{"title":"Review on ASDEX Upgrade operation with tungsten plasma facing components","authors":"R. Neu, C. Angioni, V. Bobkov, R. Dux, J. Hobirk, A. Kallenbach, K. Krieger, T. Pütterich, V. Rohde, K. Schmid","doi":"10.1016/j.nme.2026.102063","DOIUrl":"10.1016/j.nme.2026.102063","url":null,"abstract":"<div><div>With the decision of ITER to start its operation with tungsten as plasma facing material also for the main chamber plasma facing components, the interest in the consequences of the use of W was strongly increased. Although many investigations had already been carried out in the all-W ASDEX Upgrade, EAST and WEST tokamak experiments, the ITER decision raised many new questions. To provide a robust foundation for addressing these questions, this paper reviews the tungsten related investigations carried out in ASDEX Upgrade over the last three decades in order to summarize the results achieved so far and to provide a comprehensive list of references for more detailed reading. Further to conclude from this material which results can be used directly for the full-W ITER, where further work is needed and possibly rewarding and which areas are difficult to be researched in AUG and other present-day devices.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"46 ","pages":"Article 102063"},"PeriodicalIF":2.7,"publicationDate":"2026-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146023237","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 : 2026-01-19DOI: 10.1016/j.nme.2026.102068
V. Haak , A. Bukowicka , A. Graband , K.D. Hanke , T. Hannappel , J. Koch , G. Motojima , E. Morishita , D. Naujoks , T. Stummer , T. Sturm , M. Tokitani , M. Villa
After the failure of a LaB-emitter used in a neutral gas pressure gauge in the Large Helical Device during deuterium operation, the effect of neutrons on the thermionic emission properties of LaB is studied in this work. For that purpose, six cylindrical LaB-samples of 8 mm length and 1 mm diameter were irradiated with neutron doses between at the TRIGA Mark-II reactor. Analysis after neutron irradiation showed accumulation of oxygen on the sample surfaces and the formation of cracks, holes, growth of surface layers and erosion at the sample edges. In order to study the thermionic emission properties of the neutron-irradiated LaB-samples, they were used as emitters in a neutral gas pressure gauge under vacuum conditions and in a magnetic field. The tests revealed significantly reduced thermionic emission directly after neutron irradiation that improves when repeating the measurements. Four out of six LaB-emitters eventually reach thermionic emission properties comparable to the reference emitters again, due to either the removal of the lanthanum-oxide surface layer from the emitter surface during operation in the neutral gas pressure gauge or the thermal recovery of neutron-induced lattice defects.
{"title":"Effects of neutron irradiation on the thermionic emission properties of LaB6-emitters used in neutral gas pressure gauges","authors":"V. Haak , A. Bukowicka , A. Graband , K.D. Hanke , T. Hannappel , J. Koch , G. Motojima , E. Morishita , D. Naujoks , T. Stummer , T. Sturm , M. Tokitani , M. Villa","doi":"10.1016/j.nme.2026.102068","DOIUrl":"10.1016/j.nme.2026.102068","url":null,"abstract":"<div><div>After the failure of a LaB<span><math><msub><mrow></mrow><mrow><mn>6</mn></mrow></msub></math></span>-emitter used in a neutral gas pressure gauge in the Large Helical Device during deuterium operation, the effect of neutrons on the thermionic emission properties of LaB<span><math><msub><mrow></mrow><mrow><mn>6</mn></mrow></msub></math></span> is studied in this work. For that purpose, six cylindrical LaB<span><math><msub><mrow></mrow><mrow><mn>6</mn></mrow></msub></math></span>-samples of 8 mm length and 1 mm diameter were irradiated with neutron doses between <span><math><mrow><mn>1</mn><mi>⋅</mi><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mn>16</mn></mrow></msup><mo>−</mo><mn>3</mn><mi>⋅</mi><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mn>17</mn></mrow></msup></mrow></math></span> <!--> <span><math><mfrac><mrow><mtext>n</mtext></mrow><mrow><msup><mrow><mtext>cm</mtext></mrow><mrow><mn>2</mn></mrow></msup></mrow></mfrac></math></span> at the TRIGA Mark-II reactor. Analysis after neutron irradiation showed accumulation of oxygen on the sample surfaces and the formation of cracks, holes, growth of surface layers and erosion at the sample edges. In order to study the thermionic emission properties of the neutron-irradiated LaB<span><math><msub><mrow></mrow><mrow><mn>6</mn></mrow></msub></math></span>-samples, they were used as emitters in a neutral gas pressure gauge under vacuum conditions and in a magnetic field. The tests revealed significantly reduced thermionic emission directly after neutron irradiation that improves when repeating the measurements. Four out of six LaB<span><math><msub><mrow></mrow><mrow><mn>6</mn></mrow></msub></math></span>-emitters eventually reach thermionic emission properties comparable to the reference emitters again, due to either the removal of the lanthanum-oxide surface layer from the emitter surface during operation in the neutral gas pressure gauge or the thermal recovery of neutron-induced lattice defects.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"46 ","pages":"Article 102068"},"PeriodicalIF":2.7,"publicationDate":"2026-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146023234","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 : 2026-01-17DOI: 10.1016/j.nme.2026.102067
Daniel Dickes , Bernd Böswirth , Katja Hunger , Gabriel Peyron , Quentin Tichit , Marianne Richou , Johann Riesch , Mehdi Firdaouss , Valerio Tomarchio , Rudolf Neu
During the process of developing actively cooled divertor plasma-facing components for JT-60SA, a fusion experiment in Japan built within the framework of the “Broader Approach Agreement” between the European Union and Japan, three small-scale divertor mock-ups have been manufactured. The mock-ups follow the flat-tile design, i.e., have plasma-facing armour tiles joined to an actively cooled heat sink. One mock-up has tungsten (W) armour tiles, and two mock-ups have carbon (C) armour tiles, with the heat sink material being the molybdenum alloy TZM. The joining was realized via diffusion bonding with a titanium interlayer. In this work, the thermo-mechanical behaviour of the mock-ups is assessed with the high heat flux test facility GLADIS in order to qualify the joining technology. This includes screening tests up to a heat flux of 15 MW/m2 and cyclic loading with a heat flux of 10 MW/m2 for 10 s. During high heat flux testing, pyrometer and thermocouple temperature measurements, digital camera images, and thermographic imaging were used to monitor the mock-ups. In addition, comparative infrared thermography tests and visual characterizations before and after high heat flux testing were performed, including the preparation of cross-sections for scanning electron microscopy. Debonding of the armour tiles did not occur during high heat flux testing, indicating that the diffusion bonding process is suitable. However, this work outlines challenges like a potentially decreasing heat removal capability of the TZM heat sink during cyclic loading or the occurrence of detrimental deep cracking in the case of W armour tiles.
{"title":"High heat flux testing of actively cooled graphite- and tungsten-armoured JT-60SA flat tile divertor mock-ups","authors":"Daniel Dickes , Bernd Böswirth , Katja Hunger , Gabriel Peyron , Quentin Tichit , Marianne Richou , Johann Riesch , Mehdi Firdaouss , Valerio Tomarchio , Rudolf Neu","doi":"10.1016/j.nme.2026.102067","DOIUrl":"10.1016/j.nme.2026.102067","url":null,"abstract":"<div><div>During the process of developing actively cooled divertor plasma-facing components for JT-60SA, a fusion experiment in Japan built within the framework of the “Broader Approach Agreement” between the European Union and Japan, three small-scale divertor mock-ups have been manufactured. The mock-ups follow the flat-tile design, i.e., have plasma-facing armour tiles joined to an actively cooled heat sink. One mock-up has tungsten (W) armour tiles, and two mock-ups have carbon (C) armour tiles, with the heat sink material being the molybdenum alloy TZM. The joining was realized via diffusion bonding with a titanium interlayer. In this work, the thermo-mechanical behaviour of the mock-ups is assessed with the high heat flux test facility GLADIS in order to qualify the joining technology. This includes screening tests up to a heat flux of 15 <!--> <!-->MW/m<sup>2</sup> and cyclic loading with a heat flux of 10 <!--> <!-->MW/m<sup>2</sup> for 10 <!--> <!-->s. During high heat flux testing, pyrometer and thermocouple temperature measurements, digital camera images, and thermographic imaging were used to monitor the mock-ups. In addition, comparative infrared thermography tests and visual characterizations before and after high heat flux testing were performed, including the preparation of cross-sections for scanning electron microscopy. Debonding of the armour tiles did not occur during high heat flux testing, indicating that the diffusion bonding process is suitable. However, this work outlines challenges like a potentially decreasing heat removal capability of the TZM heat sink during cyclic loading or the occurrence of detrimental deep cracking in the case of W armour tiles.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"46 ","pages":"Article 102067"},"PeriodicalIF":2.7,"publicationDate":"2026-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146023235","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 : 2026-01-17DOI: 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":"2026-01-17","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}
Pub 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":"2026-01-14","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 : 2026-01-12DOI: 10.1016/j.nme.2026.102062
Z.H. He , X.B. Ye , X.W. Chen
Due to their excellent physical properties, tungsten (W) metal and its alloys are regarded as the most promising plasma-facing materials in future fusion reactors. The formation of rhenium (Re)-rich clusters induced by high-energy neutron irradiation and transmutation reactions may significantly affect the thermodynamic properties of W. In this work, we extend the previous tight-binding (TB) potential model for pure W to the W-Re binary system. We have not only improved the existing TB potential for W-W interactions but also developed new potentials for Re-Re and W-Re interactions. Benchmark calculations demonstrate that our proposed TB model has good performance in dealing with the structures, mechanical, and electronic properties as well as defect characteristics in these systems. Notably, the model’s predictions for some key irradiation-induced defects involving Re in bulk W show good agreement with the DFT results. Consequently, the present potentials show strong potential for applications in modeling radiation damage in W-Re systems.
{"title":"Tight-binding potential model for Re and W-Re alloy","authors":"Z.H. He , X.B. Ye , X.W. Chen","doi":"10.1016/j.nme.2026.102062","DOIUrl":"10.1016/j.nme.2026.102062","url":null,"abstract":"<div><div>Due to their excellent physical properties, tungsten (W) metal and its alloys are regarded as the most promising plasma-facing materials in future fusion reactors. The formation of rhenium (Re)-rich clusters induced by high-energy neutron irradiation and transmutation reactions may significantly affect the thermodynamic properties of W. In this work, we extend the previous tight-binding (TB) potential model for pure W to the W-Re binary system. We have not only improved the existing TB potential for W-W interactions but also developed new potentials for Re-Re and W-Re interactions. Benchmark calculations demonstrate that our proposed TB model has good performance in dealing with the structures, mechanical, and electronic properties as well as defect characteristics in these systems. Notably, the model’s predictions for some key irradiation-induced defects involving Re in bulk W show good agreement with the DFT results. Consequently, the present potentials show strong potential for applications in modeling radiation damage in W-Re systems.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"46 ","pages":"Article 102062"},"PeriodicalIF":2.7,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146022934","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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