Pub Date : 2026-01-02DOI: 10.1016/j.jnucmat.2026.156436
N. Kvashin , N. Anento , L. Malerba
The mechanical properties of crystalline materials such as metals, are strongly related to the mobility of dislocations, which is directly affected by their interaction with other defects present in the microstructure and acting as obstacles. Under irradiation conditions the number density of point defects increases substantially, leading to several phenomena at the atomic scale, some of which are related with the behaviour of dislocations as sinks for vacancies and self-interstitial atoms. In this work we present an in-depth study of the segregation process of point defects to an edge dislocation in α-Fe, performed with an on-the-fly kinetic Monte Carlo model, the kinetic activation-relaxation technique (k-ART). Our KMC simulations show that, in the vicinity of the dislocation core, the dynamics of vacancies and SIAs is accelerated before absorption. For the former, the preferential path is along the compression region while for the latter is along the tensile region. This work therefore provides a greater knowledge of the dynamic properties of point defects around of dislocations, such as free migration time, acceleration/deceleration of point defects motion and energies of absorption events. These results will allow more precise modelling of the microstructure evolution of polycrystalline materials, improving the predictive capabilities of existing models in the long term. In order to ensure transferability of these findings to other KMC models, the data obtained in the simulations have been used to train a prediction model based on a Machine Learning logistic regression algorithm.
{"title":"Point defect segregation at edge dislocations in α-Fe studied by kinetic activation-relaxation technique","authors":"N. Kvashin , N. Anento , L. Malerba","doi":"10.1016/j.jnucmat.2026.156436","DOIUrl":"10.1016/j.jnucmat.2026.156436","url":null,"abstract":"<div><div>The mechanical properties of crystalline materials such as metals, are strongly related to the mobility of dislocations, which is directly affected by their interaction with other defects present in the microstructure and acting as obstacles. Under irradiation conditions the number density of point defects increases substantially, leading to several phenomena at the atomic scale, some of which are related with the behaviour of dislocations as sinks for vacancies and self-interstitial atoms. In this work we present an in-depth study of the segregation process of point defects to an edge dislocation in α-Fe, performed with an on-the-fly kinetic Monte Carlo model, the kinetic activation-relaxation technique (k-ART). Our KMC simulations show that, in the vicinity of the dislocation core, the dynamics of vacancies and SIAs is accelerated before absorption. For the former, the preferential path is along the compression region while for the latter is along the tensile region. This work therefore provides a greater knowledge of the dynamic properties of point defects around of dislocations, such as free migration time, acceleration/deceleration of point defects motion and energies of absorption events. These results will allow more precise modelling of the microstructure evolution of polycrystalline materials, improving the predictive capabilities of existing models in the long term. In order to ensure transferability of these findings to other KMC models, the data obtained in the simulations have been used to train a prediction model based on a Machine Learning logistic regression algorithm.</div></div>","PeriodicalId":373,"journal":{"name":"Journal of Nuclear Materials","volume":"622 ","pages":"Article 156436"},"PeriodicalIF":3.2,"publicationDate":"2026-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145922742","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}
Pub Date : 2026-01-02DOI: 10.1016/j.jnucmat.2025.156433
Huan Yao , Changwei Wu , Tianzhou Ye , Junmei Wu , Yingwei Wu , Ping Chen , Qianjin Xia
FeCrAl alloy serves as a promising accident-tolerant fuel cladding material for nuclear reactors. The structural integrity of nuclear fuel throughout the reactor’s service life critically depends on the cladding's creep behavior. Researchers have proposed several constitutive models to predict the high-temperature creep response of FeCrAl alloy tubes. However, the development of reasonable and reliable constitutive models necessitates extensive experimental validation due to the complex interdependencies governing creep behavior. This study aims to establish a new creep constitutive model for FeCrAl alloys through molecular dynamics (MD) simulations and experimental validation. Constitutive model parameters were fitted based on the MD simulation results of high-temperature creep of FeCrAl alloy under a wide range of grain size, temperature, and stress conditions. Subsequently, the key parameters were optimized against the material's bulk mechanical properties and biaxial creep test data. The developed constitutive model was implemented in finite element analysis (FEA) to simulate biaxial creep behavior of thin-walled FeCrAl tubes. A good quantitative agreement was observed between the FEA predictions and the measured results for both axial and hoop creep strain rates. Furthermore, the model is validated against uniaxial creep data from open literature, confirming its reliability in simulating both biaxial and uniaxial creep behavior of FeCrAl cladding tubes. The proposed model can achieve at least an order of magnitude improvement in prediction accuracy over the ORNL (Oak Ridge National Laboratory) model.
{"title":"Creep constitutive model for FeCrAl alloy cladding tube: experiments and molecular dynamics simulations","authors":"Huan Yao , Changwei Wu , Tianzhou Ye , Junmei Wu , Yingwei Wu , Ping Chen , Qianjin Xia","doi":"10.1016/j.jnucmat.2025.156433","DOIUrl":"10.1016/j.jnucmat.2025.156433","url":null,"abstract":"<div><div>FeCrAl alloy serves as a promising accident-tolerant fuel cladding material for nuclear reactors. The structural integrity of nuclear fuel throughout the reactor’s service life critically depends on the cladding's creep behavior. Researchers have proposed several constitutive models to predict the high-temperature creep response of FeCrAl alloy tubes. However, the development of reasonable and reliable constitutive models necessitates extensive experimental validation due to the complex interdependencies governing creep behavior. This study aims to establish a new creep constitutive model for FeCrAl alloys through molecular dynamics (MD) simulations and experimental validation. Constitutive model parameters were fitted based on the MD simulation results of high-temperature creep of FeCrAl alloy under a wide range of grain size, temperature, and stress conditions. Subsequently, the key parameters were optimized against the material's bulk mechanical properties and biaxial creep test data. The developed constitutive model was implemented in finite element analysis (FEA) to simulate biaxial creep behavior of thin-walled FeCrAl tubes. A good quantitative agreement was observed between the FEA predictions and the measured results for both axial and hoop creep strain rates. Furthermore, the model is validated against uniaxial creep data from open literature, confirming its reliability in simulating both biaxial and uniaxial creep behavior of FeCrAl cladding tubes. The proposed model can achieve at least an order of magnitude improvement in prediction accuracy over the ORNL (Oak Ridge National Laboratory) model.</div></div>","PeriodicalId":373,"journal":{"name":"Journal of Nuclear Materials","volume":"623 ","pages":"Article 156433"},"PeriodicalIF":3.2,"publicationDate":"2026-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145976105","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}
Pub Date : 2026-01-01DOI: 10.1016/j.jnucmat.2025.156434
Yingwei Xiong , Xingtong Liu , Wenjuan Wang , Yi Ding
Ceramic immobilization is one of the good strategies for disposal of high-level radioactive waste, but suffers from high temperature and low immobilization capacity. Herein, green spark plasma sintering (SPS) technology was reported to prepare zircon-based multiphase ceramics (x-Z) for enhanced simulated trivalent actinide (Nd3+) immobilization. The effect of Nd3+ content on the phase and microstructure evolutions of the obtained x-Z ceramics was investigated. The x-Z ceramics were prepared by SPS at low sintering temperature (1350 °C) and short time (10 min), and their Nd3+ immobilization capacity was up to 20 at% owing to the low sintering temperature and short sintering time reduced the decomposition of ZrSiO4 phase. In addition, the obtained x-Z ceramics exhibited superior aqueous stability due to the high density achieved by SPS. The green and efficient SPS technology could play a significant role in promoting the industrialization of ceramics immobilization of high-level radioactive waste.
{"title":"Enhanced immobilization of trivalent actinides in zircon-based multiphase ceramics via spark plasma sintering","authors":"Yingwei Xiong , Xingtong Liu , Wenjuan Wang , Yi Ding","doi":"10.1016/j.jnucmat.2025.156434","DOIUrl":"10.1016/j.jnucmat.2025.156434","url":null,"abstract":"<div><div>Ceramic immobilization is one of the good strategies for disposal of high-level radioactive waste, but suffers from high temperature and low immobilization capacity. Herein, green spark plasma sintering (SPS) technology was reported to prepare zircon-based multiphase ceramics (<em>x</em>-Z) for enhanced simulated trivalent actinide (Nd<sup>3+</sup>) immobilization. The effect of Nd<sup>3+</sup> content on the phase and microstructure evolutions of the obtained <em>x</em>-Z ceramics was investigated. The <em>x</em>-Z ceramics were prepared by SPS at low sintering temperature (1350 °C) and short time (10 min), and their Nd<sup>3+</sup> immobilization capacity was up to 20 at% owing to the low sintering temperature and short sintering time reduced the decomposition of ZrSiO<sub>4</sub> phase. In addition, the obtained <em>x</em>-Z ceramics exhibited superior aqueous stability due to the high density achieved by SPS. The green and efficient SPS technology could play a significant role in promoting the industrialization of ceramics immobilization of high-level radioactive waste.</div></div>","PeriodicalId":373,"journal":{"name":"Journal of Nuclear Materials","volume":"622 ","pages":"Article 156434"},"PeriodicalIF":3.2,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145922720","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}
Pub Date : 2025-12-30DOI: 10.1016/j.jnucmat.2025.156424
Yu Wang , Heng Chen , Rui Su , Bin Xu , Rulong Zhou , Dongdong Li , Yu-Wei You , Pengfei Guan , Changsong Liu
This work develops a high-accuracy artificial neural network (ANN) potential for osmium (Os) to enable large-scale irradiation damage simulations in fusion materials. The potential employs spherical harmonic-Chebyshev polynomial descriptors within a Behler-Parrinello neural network architecture, trained on an extensive dataset generated via density functional theory and ab initio molecular dynamics. Comprehensive validations demonstrate excellent agreement with reference calculations and experimental data across multiple properties: lattice constants of diverse crystal structures, elastic constants for hexagonal close-packed Os, dimer interactions, and defect formation energies (vacancies, interstitials, surfaces). The ANN potential accurately reproduces key behaviors under extreme conditions, including melting characteristics, sputtering thresholds, and primary knock-on atom collision cascades. Simulations reveal defect evolution and clustering during radiation events. This transferable potential provides a critical computational tool for investigating Os precipitation effects on tritium retention and irradiation hardening in tungsten-based plasma-facing materials for fusion reactors.
{"title":"Development of a neural network potential for osmium enables irradiation damage simulations","authors":"Yu Wang , Heng Chen , Rui Su , Bin Xu , Rulong Zhou , Dongdong Li , Yu-Wei You , Pengfei Guan , Changsong Liu","doi":"10.1016/j.jnucmat.2025.156424","DOIUrl":"10.1016/j.jnucmat.2025.156424","url":null,"abstract":"<div><div>This work develops a high-accuracy artificial neural network (ANN) potential for osmium (Os) to enable large-scale irradiation damage simulations in fusion materials. The potential employs spherical harmonic-Chebyshev polynomial descriptors within a Behler-Parrinello neural network architecture, trained on an extensive dataset generated via density functional theory and <em>ab initio</em> molecular dynamics. Comprehensive validations demonstrate excellent agreement with reference calculations and experimental data across multiple properties: lattice constants of diverse crystal structures, elastic constants for hexagonal close-packed Os, dimer interactions, and defect formation energies (vacancies, interstitials, surfaces). The ANN potential accurately reproduces key behaviors under extreme conditions, including melting characteristics, sputtering thresholds, and primary knock-on atom collision cascades. Simulations reveal defect evolution and clustering during radiation events. This transferable potential provides a critical computational tool for investigating Os precipitation effects on tritium retention and irradiation hardening in tungsten-based plasma-facing materials for fusion reactors.</div></div>","PeriodicalId":373,"journal":{"name":"Journal of Nuclear Materials","volume":"622 ","pages":"Article 156424"},"PeriodicalIF":3.2,"publicationDate":"2025-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145922741","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}
Pub Date : 2025-12-30DOI: 10.1016/j.jnucmat.2025.156426
Jiwon Mun , JungHun Park , JongDae Hong , Sebastian Lam , Peter Hosemann , Gi-dong Sim , Ho Jin Ryu
This study quantifies fracture mechanisms and interfacial fracture toughness in Cr-coated Zircaloy-4 tube systems proposed as accident-tolerant fuel (ATF) cladding, using deep-notched (DN) microtensile specimens. Three gauge configurations were tested: single-phase Zr (DN-Zr), single-phase Cr (DN-Cr), and a Zr/Cr interface located at the notch root (DN-interface). The mode I stress intensity factor (SIF) for the ideal sharp-notch geometry was obtained from an analytical correlation and calibrated by finite-element (FE) J-integral analysis (Contour Integral method using ABAQUS/Standard), showing close agreement and validating the modeling. Using this calibration, the interface fracture toughness for the DN-interface configuration was extracted. Interfacial failure exhibits two distinct modes: specimens exhibiting interface-crossing yield = 1.89 ± 0.20 MPa, while delamination-dominated specimens yield = 1.12 ± 0.02 MPa. For safety assessments of Cr-coated Zircaloy-4 applications, we suggest a conservative, weakest-mode design input of = 1.12 MPa. The calibrated methodology, combined with the conservative interfacial toughness , enables quantitative screening and optimization of coating–interface configurations for ATF cladding.
{"title":"Small-scale mechanical testing of interfacial toughness in Cr-coated zircaloy-4","authors":"Jiwon Mun , JungHun Park , JongDae Hong , Sebastian Lam , Peter Hosemann , Gi-dong Sim , Ho Jin Ryu","doi":"10.1016/j.jnucmat.2025.156426","DOIUrl":"10.1016/j.jnucmat.2025.156426","url":null,"abstract":"<div><div>This study quantifies fracture mechanisms and interfacial fracture toughness in Cr-coated Zircaloy-4 tube systems proposed as accident-tolerant fuel (ATF) cladding, using deep-notched (DN) microtensile specimens. Three gauge configurations were tested: single-phase Zr (DN-Zr), single-phase Cr (DN-Cr), and a Zr/Cr interface located at the notch root (DN-interface). The mode I stress intensity factor (SIF) <span><math><msub><mi>K</mi><mi>I</mi></msub></math></span> for the ideal sharp-notch geometry was obtained from an analytical correlation and calibrated by finite-element (FE) J-integral analysis (Contour Integral method using ABAQUS/Standard), showing close agreement and validating the modeling. Using this calibration, the interface fracture toughness for the DN-interface configuration <span><math><msub><mi>K</mi><mrow><mi>Q</mi><mo>,</mo><mtext>int</mtext></mrow></msub></math></span> was extracted. Interfacial failure exhibits two distinct modes: specimens exhibiting interface-crossing yield <span><math><msub><mi>K</mi><mrow><mi>Q</mi><mo>,</mo><mtext>int</mtext></mrow></msub></math></span> = 1.89 ± 0.20 MPa<span><math><mrow><mi>√</mi><mi>m</mi></mrow></math></span>, while delamination-dominated specimens yield <span><math><msub><mi>K</mi><mrow><mi>Q</mi><mo>,</mo><mtext>int</mtext></mrow></msub></math></span> = 1.12 ± 0.02 MPa<span><math><mrow><mi>√</mi><mi>m</mi></mrow></math></span>. For safety assessments of Cr-coated Zircaloy-4 applications, we suggest a conservative, weakest-mode design input of <span><math><msubsup><mi>K</mi><mrow><mi>Q</mi><mo>,</mo><mtext>int</mtext></mrow><mi>cons</mi></msubsup></math></span> = 1.12 MPa<span><math><mrow><mi>√</mi><mi>m</mi></mrow></math></span>. The calibrated methodology, combined with the conservative interfacial toughness <span><math><msubsup><mi>K</mi><mrow><mi>Q</mi><mo>,</mo><mtext>int</mtext></mrow><mi>cons</mi></msubsup></math></span>, enables quantitative screening and optimization of coating–interface configurations for ATF cladding.</div></div>","PeriodicalId":373,"journal":{"name":"Journal of Nuclear Materials","volume":"622 ","pages":"Article 156426"},"PeriodicalIF":3.2,"publicationDate":"2025-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145922717","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}
Pub Date : 2025-12-30DOI: 10.1016/j.jnucmat.2025.156425
Alisha J. Cramer , Peter G. Martin , Thomas B. Scott
Depleted uranium materials pose a significant challenge with respect to their safe, long-term storage, not only from a radiological standpoint, but also with regards to fire safety owing to the reactivity of finely-divided uranium material with air. The risk of pyrophoric ignition is known to be strongly dependent on the material’s specific surface area, however, other factors are known to likely play a role in either increasing or decreasing such a risk. In this article, the research to date on the pyrophoric behaviour of uranium compounds is compiled and examined with a view to understanding the factors controlling pyrophoric ignition and determining the gaps in current knowledge. Although some influencing factors, such as specific surface area, dominate ignition behaviour, several other factors can disrupt expected behaviour, demonstrating that pyrophoric ignition is a complex, dynamic interplay of different factors.
{"title":"Pyrophoricity of uranium and uranium compounds: Mechanisms, knowledge gaps, and implications for nuclear safety","authors":"Alisha J. Cramer , Peter G. Martin , Thomas B. Scott","doi":"10.1016/j.jnucmat.2025.156425","DOIUrl":"10.1016/j.jnucmat.2025.156425","url":null,"abstract":"<div><div>Depleted uranium materials pose a significant challenge with respect to their safe, long-term storage, not only from a radiological standpoint, but also with regards to fire safety owing to the reactivity of finely-divided uranium material with air. The risk of pyrophoric ignition is known to be strongly dependent on the material’s specific surface area, however, other factors are known to likely play a role in either increasing or decreasing such a risk. In this article, the research to date on the pyrophoric behaviour of uranium compounds is compiled and examined with a view to understanding the factors controlling pyrophoric ignition and determining the gaps in current knowledge. Although some influencing factors, such as specific surface area, dominate ignition behaviour, several other factors can disrupt expected behaviour, demonstrating that pyrophoric ignition is a complex, dynamic interplay of different factors.</div></div>","PeriodicalId":373,"journal":{"name":"Journal of Nuclear Materials","volume":"622 ","pages":"Article 156425"},"PeriodicalIF":3.2,"publicationDate":"2025-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145882267","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}
Copper (Cu)-based materials suffer from performance degradation due to the accumulation of radiation-induced defects, limiting their application in high-radiation environments. The van der Waals (vdW) type interface formed by introducing graphene (Gr) into Cu-based materials is expected to address the challenge of modifying dislocation characteristics in metallic interface engineering. However, specific methods to modify the interface and their impacts on radiation resistance still need further investigation and quantification. Here, we investigate the interfacial vdW dislocation in Cu/Gr composites, in order to enhance radiation resistance via atomic simulations. The results reveal that increasing Gr rotation angle can lead to a rise in the interfacial dislocation density, while increasing Gr thickness broadens dislocation core width. Quantitative analysis reveals the optimal structural parameters: a critical 15° rotation angle and 4-layer thickness of Gr correspond to point defects reductions of up to 19.5 % and 35.6 %, respectively, compared to the unmodified interface. These findings are crucial for understanding and designing new vdW/metal composites with enhanced radiation resistance.
{"title":"Interfacial dislocation engineering in copper-graphene composites: Atomic insights into enhanced radiation resistance","authors":"Qi Zhang, Zhuoxin Yan, Zhe Yan, Boan Zhong, Mingyu Gong, Yue Liu, Tongxiang Fan","doi":"10.1016/j.jnucmat.2025.156423","DOIUrl":"10.1016/j.jnucmat.2025.156423","url":null,"abstract":"<div><div>Copper (Cu)-based materials suffer from performance degradation due to the accumulation of radiation-induced defects, limiting their application in high-radiation environments. The van der Waals (vdW) type interface formed by introducing graphene (Gr) into Cu-based materials is expected to address the challenge of modifying dislocation characteristics in metallic interface engineering. However, specific methods to modify the interface and their impacts on radiation resistance still need further investigation and quantification. Here, we investigate the interfacial vdW dislocation in Cu/Gr composites, in order to enhance radiation resistance via atomic simulations. The results reveal that increasing Gr rotation angle can lead to a rise in the interfacial dislocation density, while increasing Gr thickness broadens dislocation core width. Quantitative analysis reveals the optimal structural parameters: a critical 15° rotation angle and 4-layer thickness of Gr correspond to point defects reductions of up to 19.5 % and 35.6 %, respectively, compared to the unmodified interface. These findings are crucial for understanding and designing new vdW/metal composites with enhanced radiation resistance.</div></div>","PeriodicalId":373,"journal":{"name":"Journal of Nuclear Materials","volume":"623 ","pages":"Article 156423"},"PeriodicalIF":3.2,"publicationDate":"2025-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145976099","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}
Pub Date : 2025-12-29DOI: 10.1016/j.jnucmat.2025.156419
Xiang Li , Jinsong Zhang , Shuang Dai , Ke Wang , Yi Wang , Jia Tang , Shubo Yang , Qi Cao
In zirconium-alloy corrosion models, O2− movement through the zirconium oxide film is commonly considered as the rate-determining step. SEM-EDS results in this study indicate that O2− movement is driven by the built-in electric field rather than by concentration gradients. Molecular dynamics simulations were employed to investigate O2− mobility in several zirconium oxide structures, showing that monoclinic ZrO2 with a vertical grain boundary provides the highest migration ability. To investigate irradiation effects, the study focuses on low-dose displacement damage resulting from primary knock-on atom events. The simulations including mean square displacement, trajectory and diffusion coefficient results demonstrate that such low dose irradiation induced damage generally causes minimal change in O2− mobility, suggesting a limited influence on corrosion under these conditions.
{"title":"Corrosion study of zirconium alloys via molecular dynamics simulations: I. oxygen migration in zirconium oxides under low-dose irradiation induced displacement damage","authors":"Xiang Li , Jinsong Zhang , Shuang Dai , Ke Wang , Yi Wang , Jia Tang , Shubo Yang , Qi Cao","doi":"10.1016/j.jnucmat.2025.156419","DOIUrl":"10.1016/j.jnucmat.2025.156419","url":null,"abstract":"<div><div>In zirconium-alloy corrosion models, <em>O<sup>2−</sup></em> movement through the zirconium oxide film is commonly considered as the rate-determining step. SEM-EDS results in this study indicate that <em>O<sup>2−</sup></em> movement is driven by the built-in electric field rather than by concentration gradients. Molecular dynamics simulations were employed to investigate <em>O<sup>2−</sup></em> mobility in several zirconium oxide structures, showing that monoclinic ZrO<sub>2</sub> with a vertical grain boundary provides the highest migration ability. To investigate irradiation effects, the study focuses on low-dose displacement damage resulting from primary knock-on atom events. The simulations including mean square displacement, trajectory and diffusion coefficient results demonstrate that such low dose irradiation induced damage generally causes minimal change in <em>O<sup>2−</sup></em> mobility, suggesting a limited influence on corrosion under these conditions.</div></div>","PeriodicalId":373,"journal":{"name":"Journal of Nuclear Materials","volume":"622 ","pages":"Article 156419"},"PeriodicalIF":3.2,"publicationDate":"2025-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145882264","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}
Pub Date : 2025-12-29DOI: 10.1016/j.jnucmat.2025.156420
Yu Yang , Meijiao Huang , Jixue Sui , An Li , Guangming Shen , Xiaoyong Wu , Lu Wu , Mingzhang Lin
The concentrations of soluble metal ions in the primary water circulation loop of pressurized water reactors can greatly affect the deposition behaviors of corrosion products on zirconium alloy cladding tubes at high temperatures, which is referred to as CRUD. However, while considerable progress has been made in the development of CRUD deposition models, the applicability of these models remains limited, and the impacts of Fe3+, Ni2+, Cr3+, Co2+, and Mn2+ on the microstructure of CRUD and the corrosion mechanism have not been fully incorporated into model development. The present work addresses these issues by combining experimental characterization with thermodynamic calculations to analyze the mechanism by which high-temperature aqueous solutions with different Fe3+, Ni2+, Cr3+, Co2+, and Mn2+ ion concentrations influence the CRUD deposition process on zirconium alloy cladding tubes. In addition to the composition and structure of CRUD deposits, the oxide film properties of the cladding tubes are further examined under subcooled nucleate boiling (SNB) and non-SNB conditions. The results indicate that increases in the weight of zirconium alloy cladding tubes under the non-SNB condition are due primarily to oxide film thickening under low metal ion concentrations. At high ion concentrations, a thinner oxide film was observed, which is likely attributed to modifications in the local chemical environment at the metal/oxide interface induced by the CRUD deposits. In contrast, the CRUD morphology changed under the SNB condition from cluster-like deposits without chimneys to porous structures with chimneys with increasing metal ion concentrations. Experimental results obtained under the SNB condition, in addition to the results of thermodynamic calculations of the Gibbs free energy, demonstrate that Fe3O4 and spinel compounds, such as CoFe2O4 and FeCr2O4, are the dominant phases within the CRUD deposits.
{"title":"Influence of multi-ion concentrations on corrosion product deposition on zirconium alloy cladding in high-temperature water","authors":"Yu Yang , Meijiao Huang , Jixue Sui , An Li , Guangming Shen , Xiaoyong Wu , Lu Wu , Mingzhang Lin","doi":"10.1016/j.jnucmat.2025.156420","DOIUrl":"10.1016/j.jnucmat.2025.156420","url":null,"abstract":"<div><div>The concentrations of soluble metal ions in the primary water circulation loop of pressurized water reactors can greatly affect the deposition behaviors of corrosion products on zirconium alloy cladding tubes at high temperatures, which is referred to as CRUD. However, while considerable progress has been made in the development of CRUD deposition models, the applicability of these models remains limited, and the impacts of Fe<sup>3+</sup>, Ni<sup>2+</sup>, Cr<sup>3+</sup>, Co<sup>2+</sup>, and Mn<sup>2+</sup> on the microstructure of CRUD and the corrosion mechanism have not been fully incorporated into model development. The present work addresses these issues by combining experimental characterization with thermodynamic calculations to analyze the mechanism by which high-temperature aqueous solutions with different Fe<sup>3+</sup>, Ni<sup>2+</sup>, Cr<sup>3+</sup>, Co<sup>2+</sup>, and Mn<sup>2+</sup> ion concentrations influence the CRUD deposition process on zirconium alloy cladding tubes. In addition to the composition and structure of CRUD deposits, the oxide film properties of the cladding tubes are further examined under subcooled nucleate boiling (SNB) and non-SNB conditions. The results indicate that increases in the weight of zirconium alloy cladding tubes under the non-SNB condition are due primarily to oxide film thickening under low metal ion concentrations. At high ion concentrations, a thinner oxide film was observed, which is likely attributed to modifications in the local chemical environment at the metal/oxide interface induced by the CRUD deposits. In contrast, the CRUD morphology changed under the SNB condition from cluster-like deposits without chimneys to porous structures with chimneys with increasing metal ion concentrations. Experimental results obtained under the SNB condition, in addition to the results of thermodynamic calculations of the Gibbs free energy, demonstrate that Fe<sub>3</sub>O<sub>4</sub> and spinel compounds, such as CoFe<sub>2</sub>O<sub>4</sub> and FeCr<sub>2</sub>O<sub>4</sub>, are the dominant phases within the CRUD deposits.</div></div>","PeriodicalId":373,"journal":{"name":"Journal of Nuclear Materials","volume":"622 ","pages":"Article 156420"},"PeriodicalIF":3.2,"publicationDate":"2025-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145882262","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}
Pub Date : 2025-12-29DOI: 10.1016/j.jnucmat.2025.156418
Diallo Barnes, Courtney Eckley, Mary Cernyar, Michael F. Simpson
To develop a process for chlorinating spent nuclear fuel (SNF) from light water reactors and dissolving it into a molten salt, the reactivity of several surrogate fission products (SFPs) with NiCl2 and ZrCl4 in molten LiCl – KCl was tested. ZrCl4 was created in-situ by reacting NiCl2 and Zr metal in the molten salt. Powders of SrO, La2O3, CeO2, Cs2O, and a Mo metal rod were all immersed in eutectic LiCl – KCl with initially 8.9 wt% NiCl2, likely exceeding the solubility limit. Salt samples were collected at several time intervals over 24 h and analyzed via inductively coupled plasma mass spectrometry (ICP – MS). NiCl2 did not directly react with any of the SFPs, but in situ formed ZrCl4 was reactive towards all the oxides. The Mo metal rod was virtually inert towards reaction with both NiCl2 and ZrCl4. Experiments were run at 773 or 873 K with or without stirring condition. Conversion of SrO, CeO2, and La2O3 to soluble chlorides ranged from 87 – 93 %, while Cs2O conversion was only 64 % on average. Some of the Ni metal by-product plated onto the Mo rod, which was unreactive towards chlorination. A solid containing Ni and ZrO2 settled to the bottom of the crucible.
{"title":"In – situ chlorination of simulated fission products from light water reactor fuel using ZrCl4","authors":"Diallo Barnes, Courtney Eckley, Mary Cernyar, Michael F. Simpson","doi":"10.1016/j.jnucmat.2025.156418","DOIUrl":"10.1016/j.jnucmat.2025.156418","url":null,"abstract":"<div><div>To develop a process for chlorinating spent nuclear fuel (SNF) from light water reactors and dissolving it into a molten salt, the reactivity of several surrogate fission products (SFPs) with NiCl<sub>2</sub> and ZrCl<sub>4</sub> in molten LiCl – KCl was tested. ZrCl<sub>4</sub> was created <em>in-situ</em> by reacting NiCl<sub>2</sub> and Zr metal in the molten salt. Powders of SrO, La<sub>2</sub>O<sub>3</sub>, CeO<sub>2</sub>, Cs<sub>2</sub>O, and a Mo metal rod were all immersed in eutectic LiCl – KCl with initially 8.9 wt% NiCl<sub>2</sub>, likely exceeding the solubility limit. Salt samples were collected at several time intervals over 24 h and analyzed via inductively coupled plasma mass spectrometry (ICP – MS). NiCl<sub>2</sub> did not directly react with any of the SFPs, but <em>in situ</em> formed ZrCl<sub>4</sub> was reactive towards all the oxides. The Mo metal rod was virtually inert towards reaction with both NiCl<sub>2</sub> and ZrCl<sub>4</sub>. Experiments were run at 773 or 873 K with or without stirring condition. Conversion of SrO, CeO<sub>2</sub>, and La<sub>2</sub>O<sub>3</sub> to soluble chlorides ranged from 87 – 93 %, while Cs<sub>2</sub>O conversion was only 64 % on average. Some of the Ni metal by-product plated onto the Mo rod, which was unreactive towards chlorination. A solid containing Ni and ZrO<sub>2</sub> settled to the bottom of the crucible.</div></div>","PeriodicalId":373,"journal":{"name":"Journal of Nuclear Materials","volume":"622 ","pages":"Article 156418"},"PeriodicalIF":3.2,"publicationDate":"2025-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145922725","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}