Nuclear Materials and Energy最新文献

{"title":"Effects of 14 T high magnetic field on the formation and migration behavior of CLF-1 steel corrosion products","authors":"Shu-Feng Zhang ,&nbsp;Yi-Ming Lyu ,&nbsp;Lei Peng ,&nbsp;Shan-Liang Zheng","doi":"10.1016/j.nme.2025.101906","DOIUrl":"10.1016/j.nme.2025.101906","url":null,"abstract":"<div><div>The CLF-1 steel, which is a main candidate material of cooling water pipes in fusion reactor blanket being developed in China, is not only corroded by water, but also operates in high magnetic fields. The effect of magnetic field on the corrosion process of CLF-1 steel should be considered. Currently, the corrosion of fusion reactor materials in high magnetic fields at scales of 10 T has not been studied due to the lack of suitable experimental conditions for high magnetic fields. To study the influence of high magnetic fields on the corrosion process of CLF-1 steel, corrosion experiment was carried out using a superconducting steady-state magnet in 1 wt% H₂O₂ + 0.1 wt% NaCl solution for 2 h with the 14 T high magnetic field. A contrast experiment without the magnetic field was performed. The ANSYS software was used to simulate the distribution of magnetic flux around the sample in a 14 T magnetic field. The morphology of the samples was observed and the composition of corrosion products was analyzed. The number of corrosion pits on the sample surface increases significantly at 14 T magnetic field, and the surface corrosion products around the pits appear approximately circular in shape, while the corrosion products distributing in strip shape on sample corroded without the magnetic field. The simulations show that the maximum magnetic flux density is localized in the middle of the sample, where most of the corrosion pits are distributed. Possible reasons for the influence of the magnetic field on the corrosion process could be that the Lorentz force and magnetic gradient force induced change the motion of ions and paramagnetic substances (such as O₂) respectively.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"42 ","pages":"Article 101906"},"PeriodicalIF":2.3,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143465042","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optimization and evaluation of a water-cooled target probe in linear plasma devices by computational fluid dynamics methods","authors":"Tongzhen Li ,&nbsp;Qian Xu ,&nbsp;Xin Yang ,&nbsp;Fang Ding ,&nbsp;Guang-nan Luo ,&nbsp;Haishan Zhou","doi":"10.1016/j.nme.2025.101905","DOIUrl":"10.1016/j.nme.2025.101905","url":null,"abstract":"<div><div>Effective cooling of the target probe under extreme plasma operational conditions is crucial for ensuring stable and reliable diagnostic measurements. In this study, we designed a water-cooled target probe specifically tailored for deployment in a linear plasma device (LPD). Computational Fluid Dynamics (CFD) methods were employed to evaluate and optimize the cooling performance of the target probe. CFD simulations included different probe base structures and inlet pipe types. The trade-offs between enhanced heat transfer and the associated pressure drop losses for different inlet pipe designs have been comprehensively considered. Simulation results indicated that at a Gaussian heat load of 10 MW/m², which simulates a plasma discharge scenario in the LPD, the maximum temperature of the tungsten probe tip for the optimized target probe was reduced to approximately 723 ℃. Extending the thermal analysis to a future scenario where the target probe is subjected to three adjacent plasma beams, the temperature increase of the tungsten probe tips was not significant. This robust cooling performance highlights the potential of the target probe for application in advanced linear plasma devices that feature multiple or multichannel plasma sources.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"42 ","pages":"Article 101905"},"PeriodicalIF":2.3,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143474696","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of liquid metal embrittlement on an alumina forming martensitic steel","authors":"Christopher Petersson ,&nbsp;Peter Szakalos ,&nbsp;Rachel Pettersson ,&nbsp;Mats Lundberg","doi":"10.1016/j.nme.2025.101907","DOIUrl":"10.1016/j.nme.2025.101907","url":null,"abstract":"<div><div>Liquid metal embrittlement was observed in an alumina-forming martensitic (AFM) steel tested in both liquid Pb and lead–bismuth eutectic (LBE) in the temperature range 350–550 °C and 150–550 °C, respectively, using slow strain rate testing (SSRT) in a low oxygen environment (∼10^-11 wt% O dissolved in Pb). A significant decrease in the total elongation to failure (TEF) could be observed in both environments, with LBE yielding the lowest measured TEF of 0.9 % strain at 150 °C. The elongation to failure followed the classic pattern of a ductility dip, gradually recovering with increasing testing temperature so that fully ductile behaviour was restored at 550 °C. There may be a potential to improve the performance of the AFM alloy by optimizing the microstructure through adjustments to the austenitizing, quenching and tempering conditions.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"42 ","pages":"Article 101907"},"PeriodicalIF":2.3,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143454758","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modified sink strength model for dislocation in tungsten: Dependence on temperature and probability density distribution","authors":"Hui-Zhi Ma,&nbsp;Yu-Hao Li,&nbsp;Yu-Ze Niu,&nbsp;Hong-Bo Zhou,&nbsp;Guang-Hong Lu","doi":"10.1016/j.nme.2025.101900","DOIUrl":"10.1016/j.nme.2025.101900","url":null,"abstract":"<div><div>Sink strength, as a fundamental parameter in mean-field approaches, describes the ability of sinks (e.g., dislocation lines) to capture migrating defects and is crucial for simulating the microstructure evolution of irradiation damage in nuclear materials. Here, taking body centered cubic tungsten (W) as an example, we systematically investigate the sink strength of dislocation lines using the object Kinetic Monte Carlo (OKMC) method. It is found that there are noteworthy discrepancies of sink strength between the traditional theoretical expression and OKMC simulations. This should be attributed to two factors, namely temperature and probability density distribution. The former can be derived from a master curve that has already been proposed for 1D to 3D diffusion–reaction kinetics, while the latter can be well described by a modified analytical expression of sink strength for dislocation lines. By incorporating these factors, the discrepancy between theoretical results and OKMC simulations is eliminated. Notably, the results of defect evolution in irradiated W, obtained using the modified sink strength expression, exhibit a greater consistency with experimental observations than those derived from the conventional model. These results provide a better insight into the sink strength model, and have broad implications for understanding and reproducing the microstructure evolution of irradiation defects in materials.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"42 ","pages":"Article 101900"},"PeriodicalIF":2.3,"publicationDate":"2025-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143446038","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"TALIF measurements of atomic deuterium in toroidal divertor simulator NAGDIS-T","authors":"Shin Kajita ,&nbsp;Kota Hiraiwa ,&nbsp;Hirohiko Tanaka ,&nbsp;Ryuki Iwai ,&nbsp;Mitsutoshi Aramaki ,&nbsp;Ryo Yasuhara ,&nbsp;Noriyasu Ohno","doi":"10.1016/j.nme.2025.101898","DOIUrl":"10.1016/j.nme.2025.101898","url":null,"abstract":"<div><div>The behavior of neutral deuterium (D) atoms is important for understanding the physics in the divertor region of nuclear fusion reactors. It is necessary to introduce an active measurement when considering the application to detached plasmas, where recombination processes dominate the processes determining the population distribution. In this work, we have developed a two-photon absorption laser-induced fluorescence (TALIF) system in the toroidal divertor simulator NAGDIS-T to measure D atomic density. The absolute D atomic density was obtained by calibrating the signal with the krypton TALIF signal. The gas pressure and power dependence of the D atomic density is shown. The D atomic density was in the range of 1.6 × 10¹⁸–1.4 × 10¹⁹ m⁻³, and the temperature was estimated to be <span><math><mo>&lt;</mo></math></span>0.4 <span><math><mi>eV</mi></math></span>. The behavior of the D atoms is discussed in terms of the production process.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"42 ","pages":"Article 101898"},"PeriodicalIF":2.3,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143430285","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experiment-modeling studies comparing energy dissipation in the DIII-D SAS and SAS-VW divertors","authors":"D.M. Thomas ,&nbsp;T. Abrams ,&nbsp;R. Ding ,&nbsp;D. Donovan ,&nbsp;F. Effenberg ,&nbsp;J. Herfindal ,&nbsp;A. Hyatt ,&nbsp;A.W. Leonard ,&nbsp;X. Ma ,&nbsp;R. Maurizio ,&nbsp;A.G. McLean ,&nbsp;C. Murphy ,&nbsp;J. Ren ,&nbsp;M.W. Shafer ,&nbsp;D. Truong ,&nbsp;H.Q. Wang ,&nbsp;J.G. Watkins ,&nbsp;J.H. Yu","doi":"10.1016/j.nme.2025.101903","DOIUrl":"10.1016/j.nme.2025.101903","url":null,"abstract":"<div><div>Recent DIII-D experiments on Small Angle Slot (SAS) divertors have confirmed that a combination of divertor closure and target shaping can enhance cooling across the divertor target and increase energy dissipation, but with significant dependence on B_T (toroidal magnetic field) direction. In these novel divertors, the roles of closure, target shaping, drifts, and scale lengths are all interconnected in optimizing dissipation, with the separatrix electron density n_eSEP being the key parameter associated with the level of dissipation/detachment. After modifying the original flat-targeted graphite SAS to include a V shape with a tungsten coating on the outer side of the divertor (SAS-VW), matched series of discharges were run to compare to detailed SOLPS-ITER modeling. Experimentally, when run as designed with the outer strike point at the slot vertex, SAS-VW requires nearly identical n_eSEP for detachment as the original SAS, with little difference in dissipation for the new geometry. This is in contrast to (1) earlier modeling predictions that a small change of the SAS geometry to a V shape should enhance dissipation at the same n_eSEP for magnetic configurations having better H-mode access (ion B × ∇B drift directed into the divertor), and (2) despite the achievement of significantly higher (2-7x) neutral pressures and compression in the SAS-VW slot. Comparisons of experimental density scans to the most recent SOLPS-ITER modeling with ExB drifts show reasonable agreement for dissipation/detachment onset when using separatrix density as the independent parameter. In order to help understand the discrepancy in modeled vs actual performance for the new configuration, additional measurements varying gas injection location and impurity injection were undertaken. In-slot D₂ gas fueling is more effective (5–22 %) in promoting detachment, in accord with modeling. In-slot impurity injection (N₂ or Ne) can yield 30 % lower core Z_eff and 15 % less confinement degradation after detachment compared to main chamber puffing, as well as relatively lower tungsten leakage from the divertor. Modeling can also reproduce the improved detachment seen as the strike point moves inboard of the slot vertex.</div><div>While we can explain the effects of the most important parameters causing energy dissipation in these slot divertors, it remains that many aspects of their behavior cannot be accurately modeled using state-of-art codes such as SOLPS-ITER. This is of concern for future model-driven designs utilizing similar V-shaped geometries.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"42 ","pages":"Article 101903"},"PeriodicalIF":2.3,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143436679","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Quantitative characterization of deuterium and helium retention in the marked tiles with various materials exposed to HL-2A tokamak","authors":"Yan Lyu ,&nbsp;Dongye Zhao ,&nbsp;Xue Bai ,&nbsp;Cong Li ,&nbsp;Chengming Wang ,&nbsp;Chengzhi Cao ,&nbsp;Yi Hu ,&nbsp;Wei Qian ,&nbsp;Huace Wu ,&nbsp;Ding Wu ,&nbsp;Laizhong Cai ,&nbsp;Hongbin Ding","doi":"10.1016/j.nme.2025.101902","DOIUrl":"10.1016/j.nme.2025.101902","url":null,"abstract":"<div><div>The retention of hydrogen isotopes in the fusion device is critical due to safety concerns. In this work, the deuterium (D) and helium (He) retention features in the different marked tiles exposed to HL-2A tokamak discharge plasma were quantitatively characterized using long pulse laser induced desorption-quadrupole mass spectrometer (LID-QMS) combined with SEM and EDX. The D retention originates primarily from D plasma discharges of HL-2A during 2021 campaign, and the He retention comes primarily from the helium glow discharge cleaning (He-GDC). The marked tiles materials include pure bulk W, bulk stainless steel (S.S) and W-, C-, Fe-films deposited on titanium-zirconium-molybdenum alloy (TZM) or W substrates. The LID-QMS results indicate that the D and He retention distribution along the poloidal direction of HL-2A device exhibited an overall uniformity. The sequence of the D concentration trapped in the marked tiles is C-film &gt; W-film &gt; Fe-film/bulk S.S &gt; bulk W, whereas the He retention is Fe-film &gt; bulk S.S &gt; W-film &gt; bulk W &gt; C-film. The D retention is higher than the He retention in all measured materials. And the D and He trapped in the film tiles are higher than those in bulk tiles. The probable reasons for the differences were discussed in combination with the changes of the surface micro-morphology and the elemental compositions of the marked tiles. This investigation would provide a reference for future <em>in-situ</em> application of LID-QMS to monitor the D and He retention in bulk tiles and deposited materials, and also gives the data support for fuel particle transport modelling.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"42 ","pages":"Article 101902"},"PeriodicalIF":2.3,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143422085","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The separatrix operational space of next-step fusion experiments: From ASDEX Upgrade data to SPARC scenarios","authors":"T. Eich ,&nbsp;T. Body ,&nbsp;M. Faitsch ,&nbsp;O. Grover ,&nbsp;M.A. Miller ,&nbsp;P. Manz ,&nbsp;T. Looby ,&nbsp;A.Q. Kuang ,&nbsp;A. Redl ,&nbsp;M. Reinke ,&nbsp;A.J. Creely ,&nbsp;D. Battaglia ,&nbsp;J. Hillesheim ,&nbsp;M. Wigram ,&nbsp;J.W. Hughes ,&nbsp;ASDEX Upgrade team","doi":"10.1016/j.nme.2025.101896","DOIUrl":"10.1016/j.nme.2025.101896","url":null,"abstract":"<div><div>Fusion power plants require ELM-free, detached operation to prevent divertor damage and erosion. The separatrix operational space (SepOS) is proposed as a tool for identifying access to the type-I ELM-free quasi-continuous exhaust regime. In this work, we recast the SepOS framework using simple parameters and present dedicated ASDEX Upgrade discharges to demonstrate how to interpret its results. Analyzing an extended ASDEX Upgrade database consisting of 6688 individual measurements, we show that SepOS accurately describes how the H-mode boundary varies with plasma current and magnetic field strength. We then introduce a normalized SepOS framework and LH minimum scaling and show that normalized H-Mode boundaries across multiple machines are nearly identical, suggesting that the normalized SepOS can be used to translate results between different machines. The LH minimum density predicted by SepOS is found to closely match an experimentally determined multi-machine scaling, which provides a further indirect validation of SepOS across multiple devices. Finally, we demonstrate how SepOS can be used predictively, identifying a viable type-I ELM free Quasi-Continuous-Exhaust (QCE) operational point for SPARC, at <span><math><mrow><msub><mrow><mi>n</mi></mrow><mrow><mi>e</mi><mo>,</mo><mi>s</mi><mi>e</mi><mi>p</mi></mrow></msub><mo>=</mo><mn>4</mn><mo>×</mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mn>20</mn></mrow></msup><msup><mrow><mi>m</mi></mrow><mrow><mo>−</mo><mn>3</mn></mrow></msup></mrow></math></span>, <span><math><mrow><msub><mrow><mi>T</mi></mrow><mrow><mi>e</mi><mo>,</mo><mi>s</mi><mi>e</mi><mi>p</mi></mrow></msub><mo>=</mo><mn>156</mn><mi>e</mi><mi>V</mi></mrow></math></span> and <span><math><mrow><msub><mrow><mi>α</mi></mrow><mrow><mi>t</mi></mrow></msub><mo>=</mo><mn>0</mn><mo>.</mo><mn>7</mn></mrow></math></span> — a value solidly within the QCE operational space on ASDEX Upgrade. This demonstrates how SepOS provides a concise, intuitive method for scoping ELM-free operation on next-step devices.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"42 ","pages":"Article 101896"},"PeriodicalIF":2.3,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143436680","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Improved Coulomb collision operator for kinetic ion transport with EMC3-EIRENE simulating Nitrogen seeding in medium density ITER L-mode scenario","authors":"D. Harting ,&nbsp;D. Reiser ,&nbsp;S. Rode ,&nbsp;J. Romazanov ,&nbsp;P. Börner ,&nbsp;Y. Feng ,&nbsp;H. Frerichs ,&nbsp;A. Knieps","doi":"10.1016/j.nme.2025.101887","DOIUrl":"10.1016/j.nme.2025.101887","url":null,"abstract":"<div><div>Previous simulations with the kinetic ion transport module of EMC3-EIRENE for Nitrogen seeding in a medium density ITER L-mode scenario showed that the currently simplified Coulomb collision model of EIRENE leads to a strongly overestimated confinement of the kinetic ions in the magnetic mirror regions. This simplified Coulomb collision model in EIRENE is based on an energy relaxation time only and is not changing the ratio of the parallel and perpendicular velocity components for the kinetic ions and thus does not include any scattering of the kinetic ions into the loss cone of the magnetic mirror. We have now implemented a new Coulomb collision operator in EIRENE, where the Coulomb collisions are described by a linear kinetic equation in Fokker-Planck form utilizing the Trubnikov-Rosenbluth potential functions, which includes scattering of the kinetic ions as well as friction with the background plasma. The Fokker-Planck equation is treated by an operator splitting scheme and is solved locally by a Monte-Carlo method. The choice of a small enough time step in the Monte-Carlo integration method is crucial and depends strongly on the local plasma background. Two methods to locally adapt the Monte-Carlo integration time step were implemented. One uses simply a fraction (∼10^–4) of the local Spitzer slowing down time and the other applies an adaptive time step control with error estimation. It turns out that simulations using the adaptive time step control method are up to a factor 10 faster compared to the time step control using the Spitzer slowing down time. In this work we will present the details of this newly implemented Coulomb collision operator for kinetic ions in EMC3-EIRENE and the implementation of the adaptive time step algorithm. We applied this new Coulomb collision operator in a kinetic ion simulation with EMC3-EIRENE for Nitrogen seeding, where we puffed Nitrogen from the top of the machine in an attached medium density ITER L-mode scenario (<em>n</em>_<em>sep</em> = 1×10¹⁹ m⁻³, <em>P</em>_<em>sep</em> = 20 MW). This shows that the unphysical and exaggerated confinement of the kinetic ions in the magnetic mirror regions observed with the simplified Coulomb collision model in EIRENE is now resolved with the new Coulomb collision operator, which treats the scattering of the kinetic ions into the loss cone of the magnetic mirror correctly.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"42 ","pages":"Article 101887"},"PeriodicalIF":2.3,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143465043","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Heat and particle exhaust in double-null configuration in WEST: Experimental study and modeling with SOLEDGE-EIRENE","authors":"D. Moiraf ,&nbsp;G. Ciraolo ,&nbsp;N. Fedorczak ,&nbsp;J. Morales ,&nbsp;H. Bufferand ,&nbsp;O. Février ,&nbsp;J. Gunn ,&nbsp;R. Nouailletas ,&nbsp;J. Redaud ,&nbsp;N. Rivals ,&nbsp;P. Tamain ,&nbsp;A. Gallo ,&nbsp;J. Gaspar ,&nbsp;A. Grosjean ,&nbsp;P. Hennequin ,&nbsp;S. Rienäcker ,&nbsp;N. Varadarajan ,&nbsp;L. Vermare ,&nbsp;the WEST team","doi":"10.1016/j.nme.2025.101901","DOIUrl":"10.1016/j.nme.2025.101901","url":null,"abstract":"<div><div>The WEST tokamak allows for high power steady-state plasma discharges in Lower Single-Null (LSN), Double-Null (DN) and Upper Single-Null (USN) configurations. In this contribution, first results from experimental L-mode DN discharges with 3.1 MW of additional heating in the WEST tokamak and associated modeling with the SOLEDGE-EIRENE code are presented. The goal is to investigate if the magnetic configuration could help to reduce the peak heat load on the targets, and how sensitive is the power sharing between the strike points to a change in magnetic equilibrium. This study, previously performed on other devices such as DIII-D, Alcator C-mod and MAST-U, provide new data for machines with a compact divertor configuration and tungsten walls. During the experiment, the distance between the two separatrices at the outer midplane dR_sep was scanned from –32 mm (USN) to 42 mm (LSN), with the ion Bx∇B drift directed towards the lower divertor. The measured power fall off length mapped at the outer midplane can vary between configurations but is centered around λ_q = 15.6 ± 2.4 mm. In the DN configuration, Langmuir probes measurements have shown that 86 % of the power is directed towards the outer strike points. This inner/outer imbalance is consistent with the ones measured on DIII-D, Alcator C-mod and MAST-U. The influence of ballooned radial transport, that drives most of the power towards the low field side, has been reproduced in transport simulation with imposed poloidally ballooned cross-field transport. The peak heat flux measured on all strike points is reduced by half in DN compared to LSN configuration. In certain conditions of high radiations (Ohmic discharges or with ICRH), the DN configuration can trigger a MARFE on the High-Field Side (HFS) that moves in opposition to the oscillations of the plasma vertical position. This MARFE has been measured to account for 0.3 % of the particles in the plasma. Temperature and density of the core plasma are unaffected by its presence.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"42 ","pages":"Article 101901"},"PeriodicalIF":2.3,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143430284","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}