Journal of Nuclear Materials最新文献

{"title":"Alpha-particle irradiation effects on weberite-type tantalates for nuclear waste forms","authors":"Chengjie Zhao ,&nbsp;Xi Tan ,&nbsp;Yue Xia ,&nbsp;Min Xu ,&nbsp;Qian Liao ,&nbsp;Haonan Li ,&nbsp;Longcheng Liu ,&nbsp;Hiroshi Watabe ,&nbsp;Dongyan Yang ,&nbsp;Yuhong Li","doi":"10.1016/j.jnucmat.2025.155694","DOIUrl":"10.1016/j.jnucmat.2025.155694","url":null,"abstract":"<div><div>As an important mineral phase for the immobilization of high-level radioactive waste, pyrochlore undergoes a phase transformation into a disordered fluorite structure with strong resistance to amorphization upon irradiation. However, the local atomic arrangement of this disordered fluorite reveals an ordered weberite structure. Investigating the irradiation effects on this weberite local structure can uncover the microscopic mechanisms of amorphization resistance in the disordered fluorite structure at the atomic scale. This work examines the structure and irradiation effects of two weberite-structured oxides Nd₃TaO₇ and Gd₃TaO₇. The results show that neither Nd₃TaO₇ with the <em>Cmcm</em> space group nor Gd₃TaO₇ with the <em>C222</em>_<em>1</em> space group exhibited phase transformation or amorphization under 500 keV He²⁺ ion irradiation at a maximum dose of 1 × 10¹⁷ ions/cm² (∼ 0.2 dpa), only showing lattice swelling, with Nd₃TaO₇ exhibiting a maximum swelling rate of 1.97 % and Gd₃TaO₇ a maximum swelling rate of 1.33 %. The lower symmetry of the <em>C222</em>_<em>1</em> space group structure in Gd₃TaO₇ may help reduce the accumulation of radiation-induced strain. Additionally, the relatively smaller cation radius could result in a lower cation-antisite barrier, which enhances the irradiation resistance of Gd₃TaO₇.</div></div>","PeriodicalId":373,"journal":{"name":"Journal of Nuclear Materials","volume":"607 ","pages":"Article 155694"},"PeriodicalIF":2.8,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143421686","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Deformation band corrosion as a result of applied stress and cold-work in 304 stainless steel in simulated pressurized water reactor primary water conditions","authors":"Karen Kruska ,&nbsp;David W Saxey ,&nbsp;Takumi Terachi ,&nbsp;Takuyo Yamada ,&nbsp;Daniel K Schreiber ,&nbsp;Sergio Lozano-Perez","doi":"10.1016/j.jnucmat.2025.155686","DOIUrl":"10.1016/j.jnucmat.2025.155686","url":null,"abstract":"<div><div>Stainless steels like 304SS are commonly used in pressurized water reactor primary water environments due to their excellent resistance to stress corrosion cracking (SCC). However, SCC susceptibility has been observed in cold-worked 304SS. Cold-rolling introduces a high density of defects, such as deformation bands or dislocations, into the microstructure; applied stress, even if macroscopically below the yield stress, can result in regions with high localized stresses. Cold-worked and non-cold-worked samples were exposed to 360 °C simulated PWR primary water for 1500 h with and without active loading. Corrosion susceptibility of dislocations and deformation bands induced by cold-rolling and/or applied stress was studied using high-resolution (analytical) transmission electron microscopy. Deformation bands were generated in all specimens examined in the study. Penetrative oxidation was observed in some deformation bands in each specimen. The depth of penetrative deformation band oxidation frequently exceeded the depth of grain boundary oxidation in all specimens. However, deformation band oxides generally were narrowly confined to the deformation band plane. Highly Ni-rich regions were observed beyond all oxidation fronts. Surface oxides were thicker in the specimens exposed under active loading. The implications of these findings at surfaces for deformation bands intersecting stress corrosion crack paths are discussed.</div></div>","PeriodicalId":373,"journal":{"name":"Journal of Nuclear Materials","volume":"607 ","pages":"Article 155686"},"PeriodicalIF":2.8,"publicationDate":"2025-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143421685","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of the transmutation element rhenium on the retention, desorption, and diffusion behaviors of hydrogen isotopes in tungsten","authors":"Baolong Fan ,&nbsp;Fei Sun ,&nbsp;Qihang Liu ,&nbsp;Xiao-Chun Li ,&nbsp;Jipeng Zhu ,&nbsp;Kang-Yan Lu ,&nbsp;Hui-Long Yang ,&nbsp;Hai-Shan Zhou ,&nbsp;Rui Ding ,&nbsp;Lai-Ma Luo ,&nbsp;Yasuhisa Oya ,&nbsp;Yucheng Wu","doi":"10.1016/j.jnucmat.2025.155693","DOIUrl":"10.1016/j.jnucmat.2025.155693","url":null,"abstract":"<div><div>The 14.1 MeV neutron irradiation in fusion reactors can cause significant damage to tungsten (W), leading to defect formation and the creation of various transmutation elements, with rhenium (Re) being a principal product. Hydrogen isotopes are essential as fuel for fusion reactors, but the presence of transmuted Re complicates the behavior of hydrogen isotopes in W. This study systematically investigated the behavior of hydrogen isotopes in W and W-5%Re by molecular dynamics methods. The results indicate that Re in the W bulk significantly influences the retention, desorption, and diffusion behaviors of deuterium (D). Specifically, the inhibitory effect of Re on D retention decreases with increasing temperature, and the differences in D retention between W and W-5%Re are closely linked to vacancy concentrations. The addition of Re effectively reduces these vacancy concentrations, with even small amounts proving significantly in decreasing D retention. Furthermore, the amount of D desorbed from W is higher than that from W-5%Re at a desorption temperature of 500 K. The presence of Re also increases the diffusion coefficient of D in W, although this coefficient remains relatively stable regardless of Re concentration. Regarding depth distribution, D enrichment is more pronounced near the surface of W than in W-5%Re, closely linked to vacancy concentrations. As temperature increases, more D atoms diffuse into the material's interior, with Re in the bulk of W promoting this diffusion and mitigating surface damage. This study enhances understanding of the impact of Re on hydrogen isotope behavior and supports future assessments of tritium behavior under neutron irradiation conditions.</div></div>","PeriodicalId":373,"journal":{"name":"Journal of Nuclear Materials","volume":"607 ","pages":"Article 155693"},"PeriodicalIF":2.8,"publicationDate":"2025-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143421683","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"In-pile heat conduction model of the dispersion nuclear fuel plate with particle agglomeration. Part II: Predicting the effective thermal conductivity under the in-pile thermal transfer pattern based on a deep neural network","authors":"Yingxuan Dong ,&nbsp;Xicheng Cao ,&nbsp;Xingming Peng ,&nbsp;Junnan Lv ,&nbsp;Qun Li","doi":"10.1016/j.jnucmat.2025.155692","DOIUrl":"10.1016/j.jnucmat.2025.155692","url":null,"abstract":"<div><div>In-pile dispersion nuclear fuel plate elements incorporate multiple internal heat sources and evolving interaction layers. The effective thermal conductivity of this complex heat conduction structure exhibits multivariate and highly nonlinear characteristics, requiring accurate prediction by combining numerical methods and machine learning techniques. This study developed an automated high-throughput workflow to rapidly simulate massive number of dispersion meat models with diverse microstructures, and further established the machine learning database for predicting the effective thermal conductivity. Influences of internal heat sources within fuel particles, the particle agglomeration and interaction layers were considered simultaneously in modeling. Through utilizing the database constructed by high-throughput computing, the deep neural network was successfully applied to accurately forecast the effective thermal conductivity of the in-pile dispersion meat. Furthermore, comparisons of the predictive performances determined by different distance-based point pattern analysis methods indicated that the radial distribution function (g(<em>r</em>)) served as the most effective approach for characterizing spatial discreteness in predicting the effective thermal conductivity. This work demonstrates that thermal conductivity of ceramic dispersion nuclear fuel plate elements can be enhanced via optimizing the critical microstructural features.</div></div>","PeriodicalId":373,"journal":{"name":"Journal of Nuclear Materials","volume":"607 ","pages":"Article 155692"},"PeriodicalIF":2.8,"publicationDate":"2025-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143377876","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"High-resolution characterization of cold working effects on the oxidation behavior of alumina-forming austenitic (AFA) steel in lead-bismuth eutectic (LBE) with 10–6 wt.% oxygen at 600 °C","authors":"Decang Zhang ,&nbsp;Xiaoxin Zhang ,&nbsp;Xian Zeng ,&nbsp;Jun Zhang ,&nbsp;Hao Ren ,&nbsp;Fanao Meng ,&nbsp;Qingzhi Yan","doi":"10.1016/j.jnucmat.2025.155691","DOIUrl":"10.1016/j.jnucmat.2025.155691","url":null,"abstract":"<div><div>The solution-annealed and cold-worked AFA steels with surface grinding exposed to LBE at 600 °C with 10^–6 wt.% oxygen were investigated using high-resolution characterization techniques. After 500 h exposure, both steels developed protective oxide scales. After 1700 h, solution-annealed steel exhibited dissolution corrosion pits, because Cr and Al in fine grains formed by recrystallization of the surface-grinding subsurface were depleted, forming internal (Cr, Al)₂O₃ nodules that caused the initially developed oxide scales to exfoliate due to increased local stress. Following cold working, increased dislocations and grain boundaries facilitated replenishment of Cr&amp;Al in the subsurface, maintaining the durability of external (Cr, Al)₂O₃ scales, preventing dissolution attack.</div></div>","PeriodicalId":373,"journal":{"name":"Journal of Nuclear Materials","volume":"607 ","pages":"Article 155691"},"PeriodicalIF":2.8,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143377656","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation of UO2 doped with Fe2O3 sintered under a reducing atmosphere","authors":"Tashiema L. Ulrich ,&nbsp;Tyler L. Spano ,&nbsp;Luke Sadergaski ,&nbsp;Ashley E. Shields ,&nbsp;Eddie Lopez-Honorato ,&nbsp;Grant Helmreich ,&nbsp;Benjamin T. Manard ,&nbsp;Jason Harp ,&nbsp;Andrew T. Nelson","doi":"10.1016/j.jnucmat.2025.155684","DOIUrl":"10.1016/j.jnucmat.2025.155684","url":null,"abstract":"<div><div>Nuclear fuel produced with trace amounts of transition metal additives is of potential interest for introducing intentional signatures for accelerating nuclear forensics. In this work, we investigate the effects on microstructure, grain size, crystal structure, and stoichiometry when trace amounts of Fe in the form of Fe₂O₃ are added to UO₂. Sintering of compacts with different concentrations, from 250 to 3000 ppmw, was performed under a reducing atmosphere at 1773 K. The persistence of the taggant during the fuel fabrication process as well as its impact on grain size, crystal lattice, and first-neighbor chemistry was evaluated using inductively coupled plasma–optical emission spectroscopy, powder X-ray diffraction (pXRD), Raman spectroscopy, scanning electron microscopy–backscatter electron spectroscopy, energy dispersive spectroscopy, and thermogravimetric analysis. We observed that a negligible amount of Fe was lost during sintering. Our results indicate that the feedstock, Fe₂O₃ transforms into Fe and FeO under the test sintering conditions. For all compositions, metallic Fe precipitate was found in grain boundaries as a secondary phase. The potential incorporation of ionic Fe into the UO₂ unit cell was determined by pXRD and Raman spectra.</div></div>","PeriodicalId":373,"journal":{"name":"Journal of Nuclear Materials","volume":"607 ","pages":"Article 155684"},"PeriodicalIF":2.8,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143394487","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigating the synergistic evolution of H and He with irradiation defects in Fe by a new Fe-H-He ternary potential","authors":"Hao-Xuan Huang ,&nbsp;Yu-Hao Li ,&nbsp;Tian-Ren Yang ,&nbsp;Hong-Bo Zhou ,&nbsp;Jin-Liang Li ,&nbsp;Hui-Zhi Ma ,&nbsp;Yu-Ze Niu ,&nbsp;Xiao-Chun Li ,&nbsp;Huiqiu Deng ,&nbsp;Guang-Hong Lu","doi":"10.1016/j.jnucmat.2025.155687","DOIUrl":"10.1016/j.jnucmat.2025.155687","url":null,"abstract":"<div><div>It has been demonstrated that the synergistic effect of hydrogen (H) and helium (He) has a significant promoting effect on the nucleation antungstend growth of irradiation defects, leading to severe deterioration of material performance. In order to explore the synergistic evolution behaviors of H and He with irradiation defects in iron (Fe), we have developed a new Fe-H-He ternary potential through systematic fitting and optimization. During the processes, the interaction between H and He with vacancies and interstitial defects is given prominent consideration. Based on the present potential, we further explored the cooperative evolution behaviors of H-He-void complexes. On the one hand, it is clearly observed that both H and He perfectly form a typical core-shell structure in nanovoids with He inside and H outside, which is consistent with experimental observation. The number of H atoms trapped by He-void complexes will decrease with the increasing of He/V ratios, which is due to the repulsion between H and He. On the other hand, the presence of He-void complexes has a significant promoting effect on the formation of H platelets in Fe. The stress field generated by He-void complexes facilitates the aggregation and initial formation of H platelets, and its range expands as H aggregates, ultimately resulting in the formation of H platelets. The high H concentrations are required to form H platelets at high temperature. More importantly, the formation of H platelets can induce a transition in the local Fe lattice from body-centered cubic to face-centered cubic, indicating a substantial impact on the microstructure and properties of Fe. Consequently, the new Fe-H-He potential provides a powerful tool for exploring the synergistic evolution of H-He-defects and evaluating the performance of Fe in fusion devices.</div></div>","PeriodicalId":373,"journal":{"name":"Journal of Nuclear Materials","volume":"607 ","pages":"Article 155687"},"PeriodicalIF":2.8,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143377875","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation on the SCC susceptibility of a heat-optimized l-PBF 304L stainless steel in simulated primary water","authors":"Kai Chen ,&nbsp;Yuhao Zhou ,&nbsp;Fawen Zhu ,&nbsp;Shixin Gao ,&nbsp;Quanyao Ren ,&nbsp;Kun Zhang ,&nbsp;Xiaoqing Shang ,&nbsp;Lefu Zhang","doi":"10.1016/j.jnucmat.2025.155685","DOIUrl":"10.1016/j.jnucmat.2025.155685","url":null,"abstract":"<div><div>This study examines the stress corrosion cracking (SCC) behavior of laser powder bed fusion (L-PBF) 304 L stainless steel after solution annealing (SA) in high-temperature water environments. SCC susceptibility was evaluated under both hydrogenated and oxygenated water environments at 325 °C and 15.5 MPa. The results showed that heat-treated l-PBF 304 L exhibited fully recrystallized equiaxed grains, characterized with high-density annealing twins and a uniform microstructure. Stress-strain tests revealed a marked reduction in elongation and mixed intergranular (IG) and transgranular (TG) cracking, indicating significant SCC susceptibility in both environments. Notably, hydrogenated water conditions led to a higher proportion of TG cracking, suggesting enhanced hydrogen embrittlement (HE), while oxygenated conditions favored IG cracking. Cross-sectional analysis highlighted localized strain concentration at crack tips, and precipitates were found to play a critical role in the initiation and propagation of cracks. These findings provide crucial insights into the relationship between microstructure, environmental factors, and SCC behavior in l-PBF 304 L stainless steel.</div></div>","PeriodicalId":373,"journal":{"name":"Journal of Nuclear Materials","volume":"607 ","pages":"Article 155685"},"PeriodicalIF":2.8,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143377874","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Study of thermal diffusivity degradation on Cu-OFE copper due to proton and self-ion irradiation using in situ transient grating spectroscopy","authors":"Emmanouil Trachanas ,&nbsp;Angus Wylie ,&nbsp;Andrea Bignami ,&nbsp;Nikolaos Gazis ,&nbsp;Michael P. Short ,&nbsp;Katrin Michel ,&nbsp;Carl Alwmark ,&nbsp;Evangelos Gazis ,&nbsp;Georgios Fikioris ,&nbsp;Håkan Danared","doi":"10.1016/j.jnucmat.2025.155674","DOIUrl":"10.1016/j.jnucmat.2025.155674","url":null,"abstract":"&lt;div&gt;&lt;div&gt;The operation of next-generation particle accelerator facilities with increased beam power parameters and emphasis on performance and reliability signifies the need for experimental studies on material property degradation. Literature is particularly scarce regarding the effects of ionizing radiation damage on cavity components at applicable radiation conditions, with even less extant work studying the effect of simultaneous irradiation on primary materials and their physical properties such as thermal transport. This study presents the impact on thermal diffusivity in oxygen-free electronic Cu-OFE specimens due to proton and self-ion (&lt;span&gt;&lt;math&gt;&lt;mi&gt;C&lt;/mi&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;u&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;3&lt;/mn&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt;) irradiation. Copper samples with the exactly same processing route as the bulk material for European Spallation Source (ESS) Radio-Frequency Quadrupole (RFQ) were characterized with scanning electron microscopy (SEM), X-ray diffraction (XRD) and electron backscatter diffraction (EBSD), followed by irradiation at room temperature with protons and self-ions (&lt;span&gt;&lt;math&gt;&lt;mi&gt;C&lt;/mi&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;u&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;3&lt;/mn&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt;) with fluences up to 4.25 × 10&lt;sup&gt;17&lt;/sup&gt; &lt;span&gt;&lt;math&gt;&lt;mtext&gt;p&lt;/mtext&gt;&lt;mo&gt;/&lt;/mo&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mtext&gt;cm&lt;/mtext&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt; and &lt;span&gt;&lt;math&gt;&lt;mn&gt;1.10&lt;/mn&gt;&lt;mo&gt;×&lt;/mo&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mn&gt;10&lt;/mn&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;15&lt;/mn&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt; &lt;span&gt;&lt;math&gt;&lt;mtext&gt;ions&lt;/mtext&gt;&lt;mo&gt;/&lt;/mo&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mtext&gt;cm&lt;/mtext&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt;, &lt;span&gt;&lt;math&gt;&lt;mn&gt;1.69&lt;/mn&gt;&lt;mo&gt;×&lt;/mo&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mn&gt;10&lt;/mn&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;15&lt;/mn&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt; &lt;span&gt;&lt;math&gt;&lt;mtext&gt;ions&lt;/mtext&gt;&lt;mo&gt;/&lt;/mo&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mtext&gt;cm&lt;/mtext&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt; respectively. &lt;em&gt;In situ&lt;/em&gt; ion irradiation transient grating spectroscopy (I&lt;sup&gt;3&lt;/sup&gt;TGS) was used in order to monitor radiation-induced changes in thermal diffusivity in real time. The results indicate a significant thermal diffusivity drop only after the proton irradiation (10.86%) in contrast to the results obtained for self-ions (&lt;span&gt;&lt;math&gt;&lt;mi&gt;C&lt;/mi&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;u&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;3&lt;/mn&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt;) where no significant changes (&lt;span&gt;&lt;math&gt;&lt;mo&gt;∼&lt;/mo&gt;&lt;mn&gt;3&lt;/mn&gt;&lt;mtext&gt;%&lt;/mtext&gt;&lt;/math&gt;&lt;/span&gt;) are reported. The results are compared with existing literature and correlated with the nature of post-irradiation defect structures based on the particle type. In the case of protons the contribution of hydrogen implantation in stabilization of defects and on the reduction of thermal diffusivity is discussed. &lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;I&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;3&lt;/mn&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;mi&gt;T&lt;/mi&gt;&lt;mi&gt;G&lt;/mi&gt;&lt;mi&gt;S&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt; in combination with concurrent ion irradiation offers a powerful online diagnostic tool for the evaluation of the impact of operational parameters in particle accelerat","PeriodicalId":373,"journal":{"name":"Journal of Nuclear Materials","volume":"607 ","pages":"Article 155674"},"PeriodicalIF":2.8,"publicationDate":"2025-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143237316","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Buffering the oxygen activity of uranium dioxide fuels using niobium and molybdenum as redox additives","authors":"Philippe Garcia ,&nbsp;Erwin Douguet-Bronnec ,&nbsp;Franck Fournet-Fayard ,&nbsp;Florian Le Hello ,&nbsp;Xavière Iltis ,&nbsp;Nicolas Tarisien ,&nbsp;Jacques Fouletier ,&nbsp;Marlu Cesar Steil","doi":"10.1016/j.jnucmat.2025.155647","DOIUrl":"10.1016/j.jnucmat.2025.155647","url":null,"abstract":"<div><div>We demonstrate that it is possible to control the oxygen activity of a uranium oxide fuel by incorporating additives during the manufacturing process that have a strong redox activity. To this end, we have studied the macroscopic electrochemical properties of three polycrystalline uranium dioxide samples, the first containing both molybdenum and molybdenum dioxide, the second containing niobium dioxide and the last containing no additives other than impurities. During experiments, samples were subjected to reducing and subsequently oxidizing atmospheres with respect to the oxygen partial pressure at which the oxidized and reduced forms of the additives are in equilibrium. <em>In situ</em> monitoring of the electrochemical response of the samples reveals that the presence of redox couples involving either niobium or molybdenum significantly modifies the oxygen activity of a uranium dioxide solid. Scanning Electron Microscopy (SEM), Electron Back-Scatter Diffraction (EBSD) and Energy Dispersive X-ray analysis (EDX) prior to and following the high temperature measurements, confirm the <em>in situ</em> data: the final microstructure purports to show that the electrochemical activity is controlled by the Mo/MoO₂ and the NbO₂/Nb₂O₅ couples for the molybdenum and niobium containing samples respectively.</div></div>","PeriodicalId":373,"journal":{"name":"Journal of Nuclear Materials","volume":"607 ","pages":"Article 155647"},"PeriodicalIF":2.8,"publicationDate":"2025-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143428248","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}