Journal of Nuclear Materials最新文献

{"title":"Structural evolution and compressibility trends in Ce-doped UO2","authors":"Balmukund Shukla ,&nbsp;Dasarath Maji ,&nbsp;N.R. Sanjay Kumar ,&nbsp;S. Balakrishnan ,&nbsp;Anuj Upadhyay","doi":"10.1016/j.jnucmat.2025.156040","DOIUrl":"10.1016/j.jnucmat.2025.156040","url":null,"abstract":"<div><div>Ce-doped UO₂ is an important material in nuclear research because the structural properties of Ce are similar to those of Pu. This makes Ce-doped UO₂ a valuable surrogate for studying the behavior of Pu-doped UO₂. Cerium doped UO₂ samples U_1-xCe_xO₂ (<em>x</em> = 0.2, 0.4, 0.6, 0.8) were synthesized using sol-gel method. U_1-xCe_xO₂ retains fluorite UO₂ structure with decreasing lattice parameter as Ce content is increased. The decrease in lattice parameter is due to the larger presence of tetravalent Ce cation than trivalent cations. In-situ high pressure x-ray diffraction studies were carried out to find out effect of doping Ce and study their compressibility behavior. These compounds remain in fluorite structure at least up to 25 GPa, beyond which phase transition to orthorhombic structure is seen. The ambient pressure bulk modulii for <em>x</em> = (0.2, 0.4, 0.8) in U_1-xCe_xO₂ are 216 (6) GPa, 225 (9) GPa, and 247 (8) GPa, respectively that indicates consistent increase in the bulk modulus of the material when Ce content is increased. The behavior of bulk modulus with Ce doping follows lattice parameter i.e. smaller lattice shows lesser compressibility.</div></div>","PeriodicalId":373,"journal":{"name":"Journal of Nuclear Materials","volume":"616 ","pages":"Article 156040"},"PeriodicalIF":2.8,"publicationDate":"2025-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144662037","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":"Helium ion irradiation-induced hardening behavior in Ti1.5ZrHf0.5Nb0.5Ta0.5 refractory high-entropy alloys","authors":"Yuzhang Li ,&nbsp;Xuejiao Wang ,&nbsp;Aidong Lan ,&nbsp;Junwei Qiao","doi":"10.1016/j.jnucmat.2025.156037","DOIUrl":"10.1016/j.jnucmat.2025.156037","url":null,"abstract":"<div><div>Refractory high-entropy alloys (RHEAs) have emerged as the focus in the development of the first wall materials for advanced nuclear energy systems due to their outstanding high-temperature properties and irradiation resistance. However, there remains of profound research and model on the irradiation hardening behavior of refractory high-entropy alloys. In this study, Ti_1.5ZrHf_0.5Nb_0.5Ta_0.5 RHEA was subjected to 160 keV room-temperature helium ion irradiation at the doses of 0.1 dpa, 1 dpa, and 3 dpa, then the irradiation hardening behavior was analyzed by nanoindentation experiments. The results indicate that the alloys not only exhibit good strength-ductility synergy at room temperature but also possesses excellent resistance to irradiation hardening. X-ray diffraction (XRD) analysis revealed that the alloy maintained a single-phase body-centered cubic (BCC) structure after irradiation. The lattice constant exhibits an initial decrease at 0.1 dpa followed by an increase from 1 dpa to 3dpa. This is attributed to the competition between lattice relaxation and defect volume expansion. The alloys exhibited a hardening of 34.33% at the maximum irradiation dose. We utilize the plastic zone proportion factor <em>f</em> to reflect the plastic localization caused by irradiation defects. This factor is defined as the ratio of the radius of the plastic zone beneath the indenter after irradiation to the radius before irradiation. By separating the contribution of irradiation hardening using an irradiation hardening model, the plastic zone proportion factor <em>f</em> of the nanoindentation testing decreased from 1.65 to 1.32, suggesting that the increase in irradiation defects hindered the expansion of the plastic deformation volume in the alloy. Consequently, the peak of irradiation hardening shifts towards deeper depths. This study could provide an effective reference for quantifying the irradiation hardening behavior of refractory high-entropy alloys.</div></div>","PeriodicalId":373,"journal":{"name":"Journal of Nuclear Materials","volume":"616 ","pages":"Article 156037"},"PeriodicalIF":2.8,"publicationDate":"2025-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144654647","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":"Uranium nitride from uranyl citrate gel combustion and electrospray-assisted granulation","authors":"Walter Bonani,&nbsp;Jacobus Boshoven,&nbsp;Marco Cologna","doi":"10.1016/j.jnucmat.2025.156036","DOIUrl":"10.1016/j.jnucmat.2025.156036","url":null,"abstract":"<div><div>We report a novel synthesis route for uranium nitride via carbothermal reduction and nitridation of a precursor obtained by combusting a uranyl citrate gel under argon. The gel combustion results in a powder in which nanometric UO₂ islands are finely dispersed in a carbon matrix. This powder was then granulated via a novel electrospray-assisted granulation method and finally carbothermally reduced under a nitrogen atmosphere to yield single-phase UN. The UN granules were then densified to high density via spark plasma sintering, while conventional pressure-less sintering resulted in low density.</div></div>","PeriodicalId":373,"journal":{"name":"Journal of Nuclear Materials","volume":"616 ","pages":"Article 156036"},"PeriodicalIF":2.8,"publicationDate":"2025-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144654646","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":"Is hydrogen preferentially picked- up in IPHWR's pressure tubes over deuterium?","authors":"Sunil Kumar ,&nbsp;P.S. Ramanjaneyulu ,&nbsp;M. Phanindra Kumar ,&nbsp;Amit Kulkarni ,&nbsp;B.K. Nagar ,&nbsp;M.K. Saxena","doi":"10.1016/j.jnucmat.2025.156032","DOIUrl":"10.1016/j.jnucmat.2025.156032","url":null,"abstract":"<div><div>Hydrogen embrittlement is one of the major life limiting factors for zirconium-based Indian pressurized heavy water reactor (IPHWR) pressure tube materials. As part of the lifetime management of these pressure tube materials, slivering from the pressure tubes is performed during reactor shutdown condition. These samples were analyzed for hydrogen (H) and deuterium (D) content. During the analysis of these samples, it was observed that the H content is always higher than the D content, although the initial H content is maintained less than 5 ppmw and nuclear grade D₂O (D isotopic purity≥98.6%) is used as a coolant and also used to pressurize the scraping tool. According to the well-accepted mechanism for hydrogen pick-up, the nascent hydrogen/deuterium generated due to the reduction of H⁺/D⁺ at the metal and metal oxide interface is partially absorbed by the structural materials. Therefore, to understand the preferential pick-up of hydrogen isotope, Zr-2.5%Nb alloy specimens were electrolytically charged using a suitable electrolyte with a different amount of H &amp; D. In the charged specimens, H &amp; D contents were determined employing HVE-QMS technique. The hydrogen was preferentially absorbed by the Zr-2.5%Nb alloy between 5-9 times compared to deuterium for all mole fractions of H₂O &amp; D₂O in the solution under study. To investigate the effect of adsorption on isotopic preferentiality, Zr-2.5%Nb alloy samples were exposed to different compositions of H₂ and D₂ gases at 633 K. Hydrogen has 2-3 time preferentiality over deuterium for adsorption and no correlation of the composition with the preferentiality was found. Therefore, in summary, the electrolyte proton/deuteron exchange reaction, their reduction (solvation energy difference), and adsorption may be responsible for the observed preferentiality.</div></div>","PeriodicalId":373,"journal":{"name":"Journal of Nuclear Materials","volume":"616 ","pages":"Article 156032"},"PeriodicalIF":2.8,"publicationDate":"2025-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144654648","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":"Thermal diffusion behavior of ternary UMoX alloys with Al coating","authors":"Anna Oberbauer,&nbsp;Christian Schwarz,&nbsp;Bruno Baumeister,&nbsp;Tobias Chemnitz,&nbsp;Christian Reiter,&nbsp;Jingyi Shi,&nbsp;Winfried Petry","doi":"10.1016/j.jnucmat.2025.156029","DOIUrl":"10.1016/j.jnucmat.2025.156029","url":null,"abstract":"<div><div>Uranium-molybdenum (UMo) alloys are characterized by 7–10 wt.% Mo content and offer assurance in achieving high densities of U assemblies in fuel compositions, making them a compelling option for research reactors in the quest for high neutron fluxes. However, the use of these materials in fuel plates faces numerous challenges, mostly reflected in the formation of an amorphous interdiffusion layer (IDL) with poor thermal conductivity between the UMo kernel and the Al matrix or cladding. In addition, swelling of the fuel plate and accumulation of gaseous fission products can be observed. These effects can be suppressed by introducing an interdiffusion barrier layer (IDB) between the fuel and the Al matrix/cladding or using ternary alloys (UMoX) instead of binary UMo. This experiment focuses on the second approach, the investigation of ternary UMoX alloys. Zr, Pt, Nb, and Ti are selected as the third candidate element (X) because of their relevant material properties. The experimental work involved the production of UMoX alloys, with a subset of samples undergoing heat treatment at 1173 K for homogenization. All samples were coated with Al using physical vapor deposition (PVD) to mimic the Al matrix and/or cladding in fuel plates. Both the ternary alloys and binary UMo reference samples were annealed to simulate the diffusion processes expected during in-pile operation and to study γ-phase stability. The results revealed that UMoTi and UMoZr are not suitable because of irregular interdiffusion. UMoPt formed a relatively thin and regular IDL compared to that of pure UMo. UMoNb did not show interdiffusion and was chemically stable under long heat treatment. In conclusion, UMoNb and UMoPt are promising candidates for high-density fuels, offering a simpler alternative to UMo fuels, as they do not require an additional IDB layer.</div></div>","PeriodicalId":373,"journal":{"name":"Journal of Nuclear Materials","volume":"616 ","pages":"Article 156029"},"PeriodicalIF":2.8,"publicationDate":"2025-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144632916","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":"Microstructural characterization of irradiated SrTiO3 using high-resolution STEM-EDS analysis","authors":"Sho Kano ,&nbsp;Tamaki Shibayama ,&nbsp;Hiroaki Abe ,&nbsp;Takashi Nozawa","doi":"10.1016/j.jnucmat.2025.156033","DOIUrl":"10.1016/j.jnucmat.2025.156033","url":null,"abstract":"<div><div>To gain a deeper understanding of radiation-induced amorphization, high-resolution ABF/ADF and STEM-EDS techniques were utilized for the irradiation of single crystal SrTiO₃ with 160 keV O⁺ at room temperature. The results show that oxygen column damage increased with irradiation dose, however, the local specific damage level was determined from the depth profiles of irradiation dose, dose rate, and amount of implanted oxygen at different fluences. HAADF observations indicated a decrease in Sr and Ti column intensities with increasing irradiation dose, initially monotonic, then slowing above 5 dpa and accelerating again above 30 dpa. This behavior suggests that the accumulation of topological and chemical disordering depends on the damage level. STEM-EDS analysis revealed periodic concentration changes of Sr and Ti based on the atomic arrangement of the crystal in unirradiated SrTiO₃. By comparing irradiated and unirradiated samples, the concentration changes associated with oxygen implantation and the formation of chemical and topological disordering were confirmed. These results highlight the potential of STEM-EDS to characterize the evolution of irradiated microstructures in SrTiO₃, even with a relatively low spatial resolution probe. Consequently, this study offers valuable insights into the mechanisms of radiation-induced instability of SrTiO₃, contributing to the visualization of irradiation microstructure in various materials as well.</div></div>","PeriodicalId":373,"journal":{"name":"Journal of Nuclear Materials","volume":"616 ","pages":"Article 156033"},"PeriodicalIF":2.8,"publicationDate":"2025-07-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144662039","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":"Exploring differences in irradiation-induced defects between Mg2Si and Si-rich precipitates in Al-alloys","authors":"Zuojiang Wang ,&nbsp;Xujia Wang ,&nbsp;Zhengyu Liu ,&nbsp;Ziqi Cao ,&nbsp;Ling Li ,&nbsp;Yizhong Yang ,&nbsp;Hongchang Wang ,&nbsp;Shuo Cong ,&nbsp;Guang Ran","doi":"10.1016/j.jnucmat.2025.156034","DOIUrl":"10.1016/j.jnucmat.2025.156034","url":null,"abstract":"<div><div>The interfaces of precipitates serve as strong defect sinks that interact with irradiation defects, affecting the microstructure of materials. Under transmutation effects, Al-alloys in nuclear systems continuously form Mg₂Si and Si-rich precipitates. Yet, the mechanisms by which these precipitates respond to irradiation-induced self-interstitial atoms (SIAs) and vacancies, as well as the role of interfaces, remain insufficiently elucidated. In this work, the evolution of SIAs and vacancies in a 5xxx-series Al-alloys, pre-prepared with Mg₂Si and Si precipitates, was investigated through in-situ transmission electron microscopy during 400 keV Al⁺ and 30 keV He⁺ irradiation at room temperature and 523–603 K. Significant differences in defect evolution near Mg₂Si and Si-rich precipitates were observed under similar irradiation damage and He implantation. Unlike the Si precipitates, the Mg₂Si precipitates exhibited preferential nucleation and aggregation of dislocation loops on their surfaces and in surrounding regions. The differences in the behavior of SIAs and vacancies induced by the strain field and orientation relationships contributed to the variations in loop evolution for the two precipitates. After annealing, in contrast to Si-rich precipitates, Mg₂Si precipitates exhibited a stronger absorption of released vacancies, leading to pronounced faceted growth of bubbles within the precipitates. This is attributed to differences in their interfacial properties and vacancy mobility.</div></div>","PeriodicalId":373,"journal":{"name":"Journal of Nuclear Materials","volume":"616 ","pages":"Article 156034"},"PeriodicalIF":2.8,"publicationDate":"2025-07-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144633239","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":"Understanding stability of strontium titanate crystalline matrix for β and γ radiation by employing γ-γ TDPAC spectroscopy","authors":"Ashwani Kumar ,&nbsp;Manjulata Sahu ,&nbsp;B.S. Tomar ,&nbsp;S.A. Khader ,&nbsp;B.G. Vats ,&nbsp;Y.K. Bhardwaj","doi":"10.1016/j.jnucmat.2025.156031","DOIUrl":"10.1016/j.jnucmat.2025.156031","url":null,"abstract":"<div><div>Strontium titanate perovskite plays a crucial role in the formation of the SYNROC phase assemblage, providing a favorable environment for the accommodation of ⁹⁰Sr from high level radioactive waste. The matrix experiences structural deterioration as a consequence of the radiations emanating from the immobilized radioactive waste. In an effort to comprehend the impact of β, γ radiation on the stability of the strontium titanate radioactive waste immobilization matrix, Time Differential Perturbed Angular Correlation (TDPAC) spectroscopy has been employed to analyze electric hyperfine interactions (HFI) in electron beam and γ irradiated strontium Titanate (STO). Previous research reported that TDPAC spectroscopy detected two distinct interaction sites, one associated with a static HFI and the other with dynamic HFI in the pristine STO sample. In the present work, STO was subjected to electron beam and γ radiation with doses ranging from 1 to 20 MGy to mimic the consequences of β and γ radiation in the immobilization matrix and HFIs are observed. The research findings show that there is no alteration in the static HFI which suggests radiation stability of the site with static electric field gradient (EFG). However, the dynamic HFI was observed to be sensitive to EB, γ irradiation. The relaxation of the dynamic EFG (<strong>τ</strong>) increased after irradiation but with dose its behaviour is contrasting. Due to the scarcity of literature on similar studies, it is not possible to offer any insights into the cause for change in dynamic HFI due to β, γ irradiation. Possibility of radiation induced defects creation and stability of STO matrix towards radiation damage is discussed.</div></div>","PeriodicalId":373,"journal":{"name":"Journal of Nuclear Materials","volume":"616 ","pages":"Article 156031"},"PeriodicalIF":2.8,"publicationDate":"2025-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144662038","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":"A Critical Review of Machine Learning Analyses of Reactor Pressure Vessel Embrittlement and Hardening","authors":"Calum S. Cunningham,&nbsp;Susan R. Ortner","doi":"10.1016/j.jnucmat.2025.156027","DOIUrl":"10.1016/j.jnucmat.2025.156027","url":null,"abstract":"<div><div>Predicting the irradiation-induced embrittlement or hardening of nuclear reactor pressure vessels (RPVs) is key for safe long-term operation. Embrittlement trend curves (ETCs) are used to predict RPV embrittlement as a function of chemical and irradiation environment variables. There is increasing interest in applying machine learning (ML) to available mechanical testing data to produce ETCs, as opposed to conventional regression analysis. This work provides a focused review of the current state of ML applications to RPV embrittlement and identifies successes, failures and opportunities for the future.</div><div>The review shows that a wide range of ML techniques and approaches have been applied to the analysis of RPV steel embrittlement data. ML models are capable of predicting irradiation-induced embrittlement even more accurately than the leading analytical ETCs, however, this is only true when the models are interpolating within parameter spaces containing sufficient training data. When extrapolating – e.g., to a higher fluence – ML model accuracy can drastically diminish and, in some cases, fail to make physically reasonable predictions. ML investigations of the contributors to RPV embrittlement can reproduce the dominant known effects but are yet to provide insights not known from decades of coordinated research, mainly due to a lack of studies considering the effects of variables not already known to dominate embrittlement. Future work is recommended for ML to help advance the field of RPV embrittlement and perhaps improve predictions of RPV structural integrity to support long-term operation goals.</div></div>","PeriodicalId":373,"journal":{"name":"Journal of Nuclear Materials","volume":"616 ","pages":"Article 156027"},"PeriodicalIF":2.8,"publicationDate":"2025-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144654696","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":"Irradiation stability of M23C6 in representative reduced activation ferritic martensitic steels","authors":"Lijuan Cui ,&nbsp;Xunxiang Hu ,&nbsp;Manuel Pouchon ,&nbsp;Yufeng Du ,&nbsp;Yong Dai","doi":"10.1016/j.jnucmat.2025.156030","DOIUrl":"10.1016/j.jnucmat.2025.156030","url":null,"abstract":"<div><div>The irradiation stability of M₂₃C₆ precipitates in three reduced activation ferritic/martensitic steels (RAFMs) was investigated following irradiation of high-energy protons and neutrons at doses up to 21 dpa and temperatures up to 520°C in the targets of the Swiss Spallation Neutron Source. M₂₃C₆ precipitates in specimens before and after irradiation were characterized using atom probe tomography. The concentrations of Mn, Si, P and N increased significantly in M₂₃C₆ precipitates, while the W concentration in M₂₃C₆ precipitates decreased with increasing irradiation temperature. The spallation transmutation elements Ti, Sc, Ca and K were enriched in the M₂₃C₆ precipitates of irradiated specimens, The enriched elements also showed strong segregation at the M₂₃C₆-matrix interface. Cr-rich clusters and small α’ precipitates were observed near the M₂₃C₆ precipitates in F82H and Eurofer 97 specimens irradiated at about 20 dpa and 300°C. At higher irradiation temperatures (480°C and 520°C), Fe-rich clusters were formed inside M₂₃C₆ precipitates.</div></div>","PeriodicalId":373,"journal":{"name":"Journal of Nuclear Materials","volume":"616 ","pages":"Article 156030"},"PeriodicalIF":2.8,"publicationDate":"2025-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144613938","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}