Nuclear Materials and Energy最新文献

{"title":"Divertor erosion at ASDEX Upgrade during helium plasma operations","authors":"Tomi Vuoriheimo ,&nbsp;Antti Hakola ,&nbsp;Jari Likonen ,&nbsp;Karl Krieger ,&nbsp;Martin Balden ,&nbsp;Iva Bogdanović Radović ,&nbsp;Georgios Provatas ,&nbsp;Zdravko Siketić ,&nbsp;Karla Ivanković Nizić ,&nbsp;Marcin Rasinski ,&nbsp;Sebastijan Brezinsek ,&nbsp;ASDEX Upgrade Team ,&nbsp;the EUROfusion Tokamak Exploitation Team","doi":"10.1016/j.nme.2024.101766","DOIUrl":"10.1016/j.nme.2024.101766","url":null,"abstract":"<div><div>The effect of helium plasma operation on the erosion of plasma-facing components at the low-field side divertor of ASDEX Upgrade was investigated during the 2022 helium experimental campaign. A set of tungsten-covered graphite samples with small platinum marker spots was exposed to both L-mode and H-mode plasma discharges. The highest net erosion of over 1.1 nm/s was observed around the H-mode strike point similar to the case in deuterium plasma. Significant helium inventories of about 6 × 10¹⁶ He/cm² were measured in the scrape-off layer region of the divertor. Impurity deposition including boron and deuterium showed a distinct peak up to 2.4 × 10¹⁷ B/cm² and 1.0 × 10¹⁶ D/cm² between the strike points, and significant boron inventories up to 5.9 × 10¹⁶ B/cm² were also measured on the scrape-off layer side of the H-mode strike point. Platinum re-deposition was not detected between the marker spots, suggesting that it occurs only very locally within the markers. Overall erosion was, as expected, higher than in deuterium discharges, and it also remained comparatively high towards the scrape-off layer, unlike with deuterium.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"41 ","pages":"Article 101766"},"PeriodicalIF":2.3,"publicationDate":"2024-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142446673","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":"Toroidal distribution of heat load on castellated plasma facing components for lower divertor target in EAST","authors":"Wenxue Fu ,&nbsp;Dahuan Zhu ,&nbsp;Binfu Gao ,&nbsp;Zongxiao Guo ,&nbsp;Bin Zhang ,&nbsp;Mehdi Firdaouss ,&nbsp;Chuannan Xuan ,&nbsp;Rong Yan ,&nbsp;Yang Wang ,&nbsp;Chunyu He ,&nbsp;Yi Li ,&nbsp;Baoguo Wang ,&nbsp;Rui Ding ,&nbsp;Junling Chen ,&nbsp;EAST team","doi":"10.1016/j.nme.2024.101759","DOIUrl":"10.1016/j.nme.2024.101759","url":null,"abstract":"<div><div>In tokamak devices, the performance of plasma facing components (PFCs) under high heat loads is a key challenge for achieving long-pulse and high-performance plasma operations. The lower divertor of EAST adopts an ITER-like cassette modules (CMs) structure. However, regular distribution of damage along the toroidal direction have been observed on the divertor target plates, which not only affects the lifespan of PFCs but also limits the long-pulse and high-performance plasma operations. Therefore, investigating the toroidal distribution of the heat load on the divertor target in EAST is crucial for understanding the mechanism of damage on the target plate surface. The toroidal characteristics of heat loads on CMs of the lower divertor in EAST was analyzed using a three-dimensional magnetic field line tracing program (PFCFlux). For the inner vertical target (IVT) and outer vertical target (OVT) within a single CM, the heat load varies monotonically along the toroidal direction. In contrast, the heat load distribution on the outer horizontal target (OHT) is uniform, except at the chamfers, which is directly correlated with the target’s geometric structure and the magnetic field configuration. The surface heat load distribution exhibits toroidal non-uniformity, with the heat deposition pattern being generally consistent and displaying periodic variations. The toroidally uneven heat load distribution is attributed to the change in the magnetic field’s tilt angle. Additionally, the peak heat load is observed at the chamfer positions between cassettes, and an analysis is conducted on the relationship between peak heat load and the size of the chamfer. Smaller tilt angles result in lower surface heat load. Furthermore, a comparative analysis of peak heat loads at the chamfer under different plasma current conditions reveals that higher plasma currents generally result in increased peak heat loads. This investigation into the toroidal heat load distribution on the divertor surface contributes to understanding of the damage mechanism of W PFC as the target plate and provides valuable data for divertor design of future fusion devices.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"41 ","pages":"Article 101759"},"PeriodicalIF":2.3,"publicationDate":"2024-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142441326","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":"Fabrication and characterization of novel high-efficiency and high-durability neutron-absorbing Ni-based alloys","authors":"Jie Pan ,&nbsp;Ao Liu ,&nbsp;Chundong Wang ,&nbsp;Jun Li ,&nbsp;Zhaoyu Wu ,&nbsp;Xueshan Xiao","doi":"10.1016/j.nme.2024.101768","DOIUrl":"10.1016/j.nme.2024.101768","url":null,"abstract":"<div><div>New neutron-absorbing Ni-based functional alloys that depend on the gadolinium and dysprosium neutron absorption units were fabricated using vacuum induction melting. The effects of Gd and Dy contents on the microstructure characteristics and properties of Ni-based alloys were investigated. Adding Gd, Dy, and Gd + Dy into Ni-based alloys formed Ni₅Gd, Ni₅Dy and Ni₅(Gd,Dy), respectively, and their volume fraction increased with increasing of Gd/Dy content. Different type of elements, Gd or Dy, had no obvious influence on mechanical properties and corrosion resistance, while the amount of Gd and Dy elements played an important role. The shielding properties were calculated by the Monte Carlo method, and the alloys possessed high efficiency and high durability performance due to the high contents of Gd and Dy elements. The developed alloys are expected to be good functional materials for use in the field of nuclear shielding.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"41 ","pages":"Article 101768"},"PeriodicalIF":2.3,"publicationDate":"2024-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142653448","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":"Divertor tungsten source monitoring by A visible spectroscopy diagnostic on EAST","authors":"Fang Ding,&nbsp;Qing Zhang,&nbsp;Zhenhua Hu,&nbsp;Bingcheng Qi,&nbsp;Lingyi Meng,&nbsp;Rui Ding,&nbsp;Liang Wang,&nbsp;Chenyuan Zhang,&nbsp;Zhongshi Yang,&nbsp;Haishan Zhou,&nbsp;Youwen Sun,&nbsp;Guang-nan Luo,&nbsp;Jiansheng Hu","doi":"10.1016/j.nme.2024.101770","DOIUrl":"10.1016/j.nme.2024.101770","url":null,"abstract":"<div><div>EAST has been upgraded with top and bottom tungsten divertors to facilitate the high power long pulse operation. A visible spectroscopy diagnostic has been developed progressively to monitor W source as well as line emissions from other particles (e.g., D, He, Li, B, C, N, O, Ne, Ar, Mo, D₂, WD) in the divertors. Two sets of lens installed in mid-plane port view tangentially the top and bottom divertors, respectively. Two types of optical fibers transfer the plasma light collected by the lens to three different detecting modules. High spectral resolution (λ/Δλ ∼ 14000) can be achieved by the detecting module consisting of spectrometer and Electron-Multiplying Charge Coupled Device (EMCCD), high temporal resolution (50 μs) is obtained by filtered photoelectric multiplier (PMT), and high spatial resolution (1 mm) is acquired by Complementary Metal-Oxide-Semiconductor Transistor (CMOS) camera with collimation optics. The multichannel optical fiber array with 500 μm core diameter is used to connect the lens and the first two detecting modules. The imaging fiber bundle with 30 μm core diameter transmits the two-dimensional divertor plasma light to the third detecting module, i.e. collimation optics and CMOS camera. The diagnostic is operated automatically in normal EAST discharges to support experimental operation and divertor physics study. The paper presents a technical description of the diagnostic and typical measurements during EAST discharges.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"41 ","pages":"Article 101770"},"PeriodicalIF":2.3,"publicationDate":"2024-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142525923","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":"Survey of tungsten gross erosion from main plasma facing components in WEST during a L-mode high fluence campaign","authors":"N. Fedorczak ,&nbsp;C. Arnas ,&nbsp;L. Cappelli ,&nbsp;L. Colas ,&nbsp;Y. Corre ,&nbsp;M. Diez ,&nbsp;A. Gallo ,&nbsp;J. Gaspar ,&nbsp;A. Grosjean ,&nbsp;C. Guillemaut ,&nbsp;J.P. Gunn ,&nbsp;C. Johnson ,&nbsp;C. Martin ,&nbsp;E. Tsitrone ,&nbsp;E.A. Unterberg ,&nbsp;J. Bucalossi ,&nbsp;WEST team","doi":"10.1016/j.nme.2024.101758","DOIUrl":"10.1016/j.nme.2024.101758","url":null,"abstract":"<div><div>An initial high fluence campaign was performed in WEST, in 2023, on the newly installed actively cooled tungsten divertor composed of ITER-grade monoblocks. The campaign consisted in the repetition of a 60 s long Deuterium L-mode pulse in attached divertor conditions, cumulating over 10000s of plasma exposure. A maximum deuterium fluence of approximately <span><math><mrow><mn>5</mn><mi>⋅</mi><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mn>26</mn></mrow></msup></mrow></math></span> m⁻² was reached in the outer strike point region, representative of a few high performance ITER pulses. Gross tungsten erosion inferred from visible spectroscopy shows that the most eroded plasma facing component is the inner divertor target with rates ten times larger than on the outer divertor target. The outer midplane tungsten bumpers, located a few centimeters from the plasma, show gross erosion rates two times lower than at the outer divertor. We conclude that the outer midplane bumpers have a negligible contribution to the long range tungsten migration and deposition onto the lower divertor. The cumulated gross erosion rate on the inner divertor translates in an effective gross erosion thickness of about <span><math><mrow><mn>20</mn><mspace></mspace><mi>μ</mi><mi>m</mi></mrow></math></span>, while it is about <span><math><mrow><mn>2</mn><mspace></mspace><mi>μ</mi><mi>m</mi></mrow></math></span> for the outer divertor. Strikingly, these orderings coincide with the thickness of deposits found locally on the divertor: the exposed surfaces of high field side monoblocks are covered with several tens of <span><math><mrow><mi>μ</mi><mi>m</mi></mrow></math></span> tungsten deposits, while on the lower field side, few <span><math><mrow><mi>μ</mi><mi>m</mi></mrow></math></span> thin tungsten deposits are only found on the magnetically shadowed parts of monoblocks. The strong impact of those deposits on WEST operation, namely perturbation of surface temperature measurement with infra-red thermography, and the emission of flakes causing radiative perturbation of the confined plasma, calls for anticipating similar issues in ITER. In particular, the start of research operation shall consider the definition of a divertor erosion budget in order to anticipate the formation of deleterious deposits.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"41 ","pages":"Article 101758"},"PeriodicalIF":2.3,"publicationDate":"2024-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142525926","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":"Post-mortem analysis of the deposit layers on the lower divertor after the 2023 high particle fluence campaign of WEST","authors":"C. Martin ,&nbsp;M. Diez ,&nbsp;E. Bernard ,&nbsp;M. Cabié ,&nbsp;A. Campos ,&nbsp;C. Pardanaud ,&nbsp;G. Giacometti ,&nbsp;A. Gallo ,&nbsp;J. Gaspar ,&nbsp;Y. Corre ,&nbsp;E.Tsitrone ,&nbsp;the WEST team","doi":"10.1016/j.nme.2024.101764","DOIUrl":"10.1016/j.nme.2024.101764","url":null,"abstract":"<div><div>We analysed deposits collected on the lower divertor of WEST after the first high fluence campaign performed in 2023. Deposits were collected on the high field side (thick deposition area) of 2 ITER-grade plasma facing units (PFUs), located on different toroidal positions. Using focused ion beam cross sectioning, the deposits were found to be very thick (12–55 µm). A significant difference was observed in the toroidal direction with thicker deposits for the PFU located at the maximal heat load in the inner side, showing a deposition pattern due to the toroidal magnetic field modulation. Deposits present a complex layer-by-layer structure with dense layers, some melted parts and porosities within the layers. The deposition is mainly composed of tungsten with oxygen, boron, carbon and traces of nitrogen whose composition vary along the radial direction. We identified W-rich deposits in the high plasma flux area near the inner strike point and deposits rich in O, B, C and N in the low plasma flux area further away from this strike point. W dense layers of about 5 up to 40 µm thick in the thick deposit area near the strike point were attributed to the high fluence campaign. Pure boron layers resulting from wall conditioning and processed by plasma wall interactions were also observed.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"41 ","pages":"Article 101764"},"PeriodicalIF":2.3,"publicationDate":"2024-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142446672","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":"Enhanced thermomechanical fatigue resistance in W10Re alloys: Microstructural and surface engineering approaches","authors":"Michael Sommerauer ,&nbsp;Benjamin Seligmann ,&nbsp;Hannah Gottlieb ,&nbsp;Anton Hohenwarter ,&nbsp;Jeong-Ha You ,&nbsp;Neil Bostrom ,&nbsp;Reinhard Pippan ,&nbsp;Maximilian Siller ,&nbsp;Verena Maier–Kiener","doi":"10.1016/j.nme.2024.101769","DOIUrl":"10.1016/j.nme.2024.101769","url":null,"abstract":"<div><div>Thermomechanical fatigue of refractory metals is commonly observed in high-temperature environments like first walls and divertors for proposed fusion reactors or X-ray anodes for medical imaging. Typically, alloying with rhenium or optimized microstructures are employed to counteract or delay the detrimental effects of fatigue in tungsten. Additionally, a novel concept is the utilization of surface structures to compensate cyclic thermal stresses. This work aimed to investigate the combination of these approaches, by comparing two W10Re alloys with vastly different microstructures, as well as engineered surface conditions of varying scales. Samples were subjected to thermocyclic fatigue under pulsed electron beam exposure, mimicking the surface temperatures typically encountered in a rotating X-ray anode. Analysis of several in-situ data streams, post-mortem investigations by metallography, and finite element methods revealed the interplay between microstructure and surface modifications. The columnar microstructure exhibited higher resistance to severe surface damage compared to the globular one, linked to the deflection of cracks along grain boundaries and subsequent melting. Coarse structuring was found to partly relieve the surface stresses during thermal cycling, preventing most of the damage accumulation. A full damage relief and performance equivalence between columnar and globular microstructure was achieved by engineering fine-structured surfaces, which led to a ten-fold increase in fatigue resistance over the non-structured condition.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"41 ","pages":"Article 101769"},"PeriodicalIF":2.3,"publicationDate":"2024-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142446674","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":"Influence of phase decomposition on mechanical properties and oxidation resistance of WCrY SMART material","authors":"Jie Chen ,&nbsp;Elena Tejado ,&nbsp;Andrey Litnovsky ,&nbsp;Duc Nguyen-Manh ,&nbsp;Eric Prestat ,&nbsp;Tamsin Whitfield ,&nbsp;Jose Ygnacio Pastor ,&nbsp;Martin Bram ,&nbsp;Jan Willem Coenen ,&nbsp;Christian Linsmeier ,&nbsp;Jesus Gonzalez-Julian","doi":"10.1016/j.nme.2024.101762","DOIUrl":"10.1016/j.nme.2024.101762","url":null,"abstract":"<div><div>Self-passivating W-11.4Cr-0.6Y (in wt.%) alloy is a plasma-facing candidate armour material in fusion power plants. In the present work, the as-sintered material, fabricated via ball milling and field-assisted sintering, was annealed at 1000 °C for varying durations to induce phase decomposition. This process leads to the transformation of the initially homogeneous microstructure into two distinct phases: the W-rich phase (αW, Cr) and the Cr-rich phase (αCr, W). Cr-rich phases preferentially form at grain boundaries, where yttrium oxides are also located, and gradually coarsen to the submicron range with increasing annealing time. The chemical compositions of both phases remain relatively stable after 75 h of annealing. The Cr content in (αW, Cr) is 18.6 at.% at 75 h and 17.8 at.% at 100 h. Compared to the as-sintered state, the 100 h-annealed material exhibits significant softening at room temperature and demonstrates increased flexural strength across all tested temperatures, but lower fracture toughness at elevated temperatures. The oxidation behavior of the 100 h-annealed material under humid air at 1000 °C reveals two stages in its TGA curve: inital growth of the inner oxide layer followed by subsequent development of the protecting chromia layer. In contrast, the as-sintered material exhibits a continuous, linear mass increase throughout the oxidation process. These findings present promising prospects of the decomposed microstructure for first wall applications.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"41 ","pages":"Article 101762"},"PeriodicalIF":2.3,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142434129","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":"Evaluation of thermal properties of CuCrFeV (Ti, Ta, W, Mo) for nuclear fusion applications","authors":"A. Rodríguez-López ,&nbsp;B. Savoini ,&nbsp;M.A. Monge ,&nbsp;A. Galatanu ,&nbsp;M. Galatanu","doi":"10.1016/j.nme.2024.101767","DOIUrl":"10.1016/j.nme.2024.101767","url":null,"abstract":"<div><div>This work investigates the influence of composition on the thermal properties of the high entropy alloy family Cu₅Cr₃₅Fe₃₅V₂₀-X₅ (at. %), where X  = Ti, Ta, W or Mo in the framework of acting as a thermal barrier between the W-based plasma-facing elements and the CuCrZr or Cu-based heat sink components of the fusion reactor. The alloys were produced by arc melting and their microstructure and mechanical properties were previously characterized by XRD, SEM, and Vickers hardness measurements. Thermal properties have been measured on as-cast at thermally treated alloys using the laser flash method in the temperature range 25 °C to 600 °C to determine the thermal diffusivity, α, thermal conductivity, λ, and specific heat, C_p. Dilatometry experiments were also carried out to obtain the linear thermal expansion coefficient, CTE, as a function of temperature.</div><div>For all materials, the thermal conductivity increases with temperature from 15 W/m·K at RT to 28 W/m·K at 600 °C and does not significantly depend on the thermal treatment for the Mo-HEA and W-HEA, but increases after aging for the Ta-HEA and Ti-HEA. These values are lower than those of W (∼122 W/m·K at 600 °C) and much lower than for CuCrZr-IG (∼354 W/m·K at 400 °C). The thermal expansion coefficients of these HEAs, ∼10 × 10⁻⁶ °C⁻¹ at RT and ∼ 2 × 10⁻⁶ °C⁻¹ at 650 °C are between those of CuCrZr and the W for the entire operative temperature range. These results indicate that the Cu₅Cr₃₅Fe₃₅V₂₀-X₅ (X = Ti, Ta, W, Mo) HEAs have a promising combination of the thermophysical properties, λ, C_p and CTE, to act as thermal barrier in plasma-facing components that require the union of W- and Cu-based materials.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"41 ","pages":"Article 101767"},"PeriodicalIF":2.3,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142446671","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":"Melting behaviour of mixed plutonium and iron oxides: An experimental study","authors":"Luca Casini ,&nbsp;Lelio Luzzi ,&nbsp;Aleksander Lacima-Nadolnik ,&nbsp;Davide Robba ,&nbsp;Luka Vlahovic ,&nbsp;Dario Manara ,&nbsp;Rudy Konings ,&nbsp;Andrea Quaini ,&nbsp;Christine Guenéau","doi":"10.1016/j.nme.2024.101761","DOIUrl":"10.1016/j.nme.2024.101761","url":null,"abstract":"<div><div>The present work describes original experimental results obtained on the melting and solidification behaviour of mixed PuO₂ – Fe₃O₄ samples. The samples were laser-heated into the liquid phase in a pressurised autoclave under a controlled atmosphere of argon or air, whereby the sample temperature was measured in-situ with the help of fast pyrometers. In addition, the oxygen release in the argon experiments was measured by an O₂ probe. By these means, solidus and liquidus temperatures in the Fe₃O₄-PuO₂ system were derived as a function of the PuO₂ mole fraction at two oxygen partial pressures (pO₂ = 1e-6 and pO₂ = 0.2 bar). It was shown that the system exhibits a eutectic reaction, and that the observed liquidus and eutectic temperatures are higher for higher oxygen contents. This is due to the stabilisation of stoichiometric oxides in an oxidising atmosphere, as opposed to the appearance of oxygen-defective, lower-melting phases in an inert/reducing environment. The occurrence of the eutectic in the system was confirmed by electron microscopy analysis. It occurs at a composition between 22 mol % and 23 mol % of PuO₂ in the Fe₃O₄-PuO₂ pseudo-binary system. Outside the Fe₃O₄ – PuO₂ plane, the eutectic temperature was observed to depend upon the oxygen potential, varying from approximately 1800 K in air to approximately 1700 K in inert (Ar) gas. The experimental solidus/liquidus data were used to derive a thermodynamic model on the system. Thermodynamic calculations supported the oxygen release of the samples in both argon and air and the interpretation of the quenched microstructure of the samples.</div></div>","PeriodicalId":56004,"journal":{"name":"Nuclear Materials and Energy","volume":"41 ","pages":"Article 101761"},"PeriodicalIF":2.3,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142434130","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}