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Three-dimensional fracture of UO2 ceramic pellets by phase field modeling

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Science China(Physics,Mechanics & Astronomy) 2025年第1期Mechanics & Astronomy) .卷 169-180页

作者： Wei Xiong Xuan Ye Hongzhang Cheng Xiaoming Liu Institute of nuclear and New Energy Technology Collaborative Innovation Center of Advanced Nuclear Energy Technology Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of Education Tsinghua University State Key Laboratory of Nonlinear Mechanics Institute of Mechanics Chinese Academy of Sciences school of Engineering Science University of Chinese Academy of Sciences

Fracture is the primary failure type for the UO2ceramic pellets,which are operated under irradiation and thermal processes,and physically confined by the *** this work,by combining closely coupled physical processes of heat conduction,heat transfer,and mechanical deformation with the cohesive phase field framework,we proposed a high-precision modeling of quasistatic cracking of three-dimensional （3D） UO2ceramic fuel pellets under high temperature and *** simulation results agree well with the experimental results,indicating that the proposed method has the potential to capture 3D crack modes in the interested time ***,we studied the relation of the 3D fracture patterns of fuel pellets with the peak power *** was found that the power level plays a critical role in determining the competition between radial and circumferential cracks,as well as transverse penetrating cracks.

关键词： phase field method nuclear fuel pellet coupled thermo-mechanical model thermal fracture

Development of a general circumferentially nonuniform heat transfer fuel rod model for subchannel analysis and application to helical fuel rods

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Science China Technological Sciences 2025年

作者： Junsen FU Junlong LI Xiaowen WANG Qi ZHANG Yao XIAO Hanyang GU school of Mechanical Engineering Shanghai Jiao Tong University Key Laboratory of nuclear Power Systems and Equipment of the Ministry of Education Shanghai Jiao Tong University National Key Laboratory of nuclear Reactor Technology Nuclear Power Institute of China State Key Laboratory of nuclear Power Safety Technology and Equipment Shanghai Jiao Tong University

The subchannel analysis method is one of the most crucial transient safety analysis methods in the thermal design of nuclear reactors. The nonuniformity of circumferential heat transfer is slight in conventional pressurized water reactor (PWR)cores, but it is significant in advanced reactors with wire-wrapped or helical fuel rods. Predicting circumferentially nonuniform heat transfer behavior can be challenging owing to the complex geometry of helical fuel rods. In this study, a general circumferentially nonuniform heat transfer fuel rod (GCNF) model is developed to predict the fuel central temperature and circumferential heat flux and wall temperature. This model incorporates a refined two-dimensional fuel conduction model and circumferential nonuniform shape factor, addressing the dual factors contributing to the circumferential nonuniformity of helical fuel rods. An empirical correlation for the nonuniform shape factor is developed based on the computational fluid dynamics (CFD) results, and it is implemented to the subchannel code. The newly developed model is applied to a helical fuel annulus and validated by comparing the prediction results with CFD data. The maximum wall temperature predicted by the code is 1.15°C lower than the value calculated through CFD. In terms of the heat flux, the maximum value at the inner corner is22 kW lower than that obtained from the CFD prediction. The accurate prediction of circumferentially nonuniform heat transfer in helical fuel, concerning the surface heat flux and cladding temperature, addresses existing shortcomings in helical fuel subchannel analysis methods. Additionally, the capability to predict the fuel central temperature is essential for the safety analysis to determine whether fuel rods are melting. The generality of the model framework allows it to be used for the prediction of circumferential nonuniform heat transfer behavior in other types of fuel assemblies.

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Vector meson's spin alignments in high energy reactions

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Science China(Physics,Mechanics & Astronomy) 2025年第1期Mechanics & Astronomy) .卷 5-20页

作者： Jin-Hui Chen Zuo-Tang Liang Yu-Gang Ma Xin-Li Sheng Qun Wang Key Laboratory of nuclear Physics and Ion-beam Application (MoE) Institute of Modern PhysicsFudan University Institute of Frontier and Interdisciplinary Science Key Laboratory of Particle Physics and Particle Irradiation (MOE)Shandong University INFN-Firenze Department of Modern Physics University of Science and Technology of China school of Mechanics and Physics Anhui University of Science and Technology

The global spin alignment of vector mesons has been observed by the STAR collaboration at the Relativistic Heavy Ion Collider （RHIC） at Brookhaven National Laboratory （BNL）.It provides a unique opportunity to probe the correlation between the polarized quark and antiquark in the strongly coupled quark-gluon plasma （sQGP） produced in relativistic heavy ion collisions,opening a new window to explore the properties of s *** addition,spin alignments of vector mesons have also been observed in other high-energy particle collisions such as e+e-annihilations at high energies where hadron production is dominated by quark fragmentation *** results obtained are quite different from those obtained in heavy ion collisions where quark coalescence/combination mechanism dominates suggesting strong dependence on hadronization *** comprehensive studies in different hadronization processes are *** this article,we present a brief review of theoretical and experimental advances in the study of vector meson’s spin alignments in a variety of high-energy particle collisions,with emphasis on hadronization mechanisms.

关键词： vector meson spin alignment global polarization relativistic heavy ion collisions fragmentation

Effects of salt and nitrogen on physiological indices and carbon isotope discrimination of wheat cultivars in the northeast of Iran

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Journal of Integrative agriculture 2020年第3期19卷 656-667页

作者： Azam BORZOUEI MirAhmad MOUSAVI SHALMANI Ali ESKANDARI nuclear agriculture Research school Nuclear Science and Technology Research Institute(NSTRI)

In order to study the effects of different levels of salt stress and nitrogen(N) on physiological mechanisms,carbon isotope discrimination(△13C),and yield of two wheat cultivars(cv.),a two-year field experiment was carried out during *** treatments included three levels of salt stress(1.3,5.2,and 10.5 dS m^-1),three levels of N(50,100,and 150 kg N ha-1),and two wheat cultivars,Bam and *** salt stress,N application(100 and 150 kg N ha^-1) produced a significant effect on both cultivars with respect to physiological traits,i.e.,net photosynthetic rate(Pn),stomatal conductance(gs),chlorophyll index(Cl),Na^+/K^+ ratio as well as the grain yield(GY).The salt-tolerant and-sensitive cultivars exhibited the maximum values of physio-biochemical and yield attributes at 100 and 150 kg N ha-1,*** results of △13C showed a significant difference(P<0.001) between wheat cultivars under the control and salt *** to our result,salt-tolerant cultivar Bam seems to be more efficient in terms of higher GY,Pn,gs,Cl,and lower Na^+/K^+ ratio as well as higher △13C as compared with salt-sensitive cultivar Toos,under salt ***,a significant positive correlation that observed between △13C and GY,indicated that △13C may be an effective index for indirect selection of yield potential in wheat under irrigation regimes with saline water.

关键词： net photosynthetic rate stomatal conductance chlorophyll index carbon isotope discrimination

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Evaluating the impacts of converting grain to vegetable fields on nitrate transport in the deep vadose zone of the North China Plain

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Journal of Geographical Sciences 2025年第1期35卷 189-212页

作者： LIU Meiying MIN Leilei WU Lin ZHANG Yucui QI Yongqing WANG Shiqin LIU Binbin GENG Di SHEN Yanjun Hebei Key Laboratory of Water-Saving agriculture Key Laboratory of Agricultural Water ResourcesCenter for Agricultural Resources ResearchInstitute of Genetics and Developmental BiologyCAS school of Advanced Agricultural Sciences University of Chinese Academy of Sciences

Nitrate （NO3-） accumulation and transport processes in the thick vadose zone affect the evolution of the groundwater NO3-content in intensive agricultural *** land-use change （ALUC）,typically accompanied by substantial alterations in nitrogen fertilizer application and irrigation practices,is an important influencing *** study evaluated the changes in NO3-accumulation and transport in the deep vadose zone （DVZ,below the root zone）,and the groundwater NO3-content associated with ALUC from grain to vegetable fields in the North China Plain （NCP）.The ALUC from grain to vegetable resulted in nitrate–nitrogen （NO3--N） accumulation in DVZ increased by 235.5 kg ha-1m-1（163.2%） in the piedmont plain and 224.9 kg ha-1m-1（102.7%） in the central plain,*** change accelerated downward transport velocity in the DVZ (from 0.81±0.47 to 0.89±0.55 m yr-1in the piedmont plain,and from 0.24±0.12 to 0.92±0.12 m yr-1in the central plain) and increased NO3-leaching *** transport velocity and leaching fluxes resulted in chemical N-fertilizer entering the aquifer in several areas in the piedmont *** impact of the agricultural activity intensity changes,accompanied by the ALUC,on groundwater quantity and quality should be considered in similar regions.

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Establishing the vector-meson-exchange dominance for the short range interactions of light quarks

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Science China(Physics,Mechanics & Astronomy) 2025年

作者： Bing-Song Zou Department of Physics Tsinghua University CAS Key Laboratory of Theoretical Physics Institute of Theoretical Physics Chinese Academy of Sciences school of Physics University of Chinese Academy of Sciences Southern Center for nuclear-Science Theory (SCNT) Institute of Modern Physics Chinese Academy of Sciences

Understanding the interactions between constituent quarks is one of the fundamental and challenging problems in hadron physics. At present, the constituent quark models have achieved great success in describing the properties of hadrons, whereas some long-standing disputes remain, especially for the short range interactions between constituent quarks. In exploring the dynamic mechanism between u/d quarks, it is found that the one gluon exchange and/or vector meson exchange induced interactions may dominate the short range interactions [1].

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Preparation and preliminary evaluation of [^(55)Co](II)vancomycin

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nuclear Science and Techniques 2008年第6期19卷 347-353页

作者： Amir Reza JALILIAN Yousef YARI-KAMRANI Pejman ROWSHANFARZAD Mahseed SABET Mohsen KAMALI-DEHGHAN Abbas MAJDABADI nuclear Medicine Research Group Agriculture Medicine and Industrial Research School (AMIRS)KarajIran

Co-55 (t1/2=17.53 h) was produced by 150 μA irradiation of a natural nickel target using 15 MeV protons. It was separated from the irradiated target material by two ion exchange chromatography steps with a radiochemical yield of >95% and was used for the preparation of [55Co]vancomycin ([55Co]VAN). Optimization studies were per- formed using Co-57 due to its longer half-life. Cobalt-57 (t1/2=271.79 d) was produced by irradiation of a natural nickel target with 150 μA current of 22 MeV protons. The 57Co was separated from the irradiated target material using a no-carrier-added method with a radiochemical yield of >97%. Both products were controlled for radionuclide and chemical purity. The solutions of [55Co]VAN were prepared (radiochemical yield>80%) starting with 55Co acetate and vancomycin at room temperature after 30 min. A precise solid phrase extraction (SPE) method was developed using Si Sep-Pak in order to purify/reconstitute the final formulation for animal studies. [55Co]VAN showed a radiochemical purity of more than 99%. The resultant specific activity was about 1.15 TBq/mmol. It is proved that the tracer is stable in the final product and in presence of human serum at 37°C up to 24 h. Biodistribution study of [55Co]VAN in normal rats was undertaken for up to 72 h.

关键词：钴-55 万古霉素医用回旋加速器放射性同位素示踪生物剂量学

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High-temperature oxidation behavior and degradation mechanism of chromium-coated zirconium alloy cladding: a review

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Tungsten 2025年第1期7卷 50-70页

作者： Yi Li Bei-Qi Wang Xin-Yin Zhang Shi-Jie Wang Cong-Yi Li Hui-Long Yang Ran-Ran Su Tong Liu school of Mechanical Engineering Shanghai Jiao Tong University College and Graduate school of Arts and Sciences University of Virginia Global Institute of Future Technology Shanghai Jiao Tong University

Accident-tolerant fuels(ATF) have been extensively studied to reduce the production rate and total amount of heat and hydrogen generated from high-temperature steam oxidation during severe ***-coated zirconium alloy cladding has become one of the most promising candidates for ATF because of its excellent corrosion and oxidation *** paper provides a comprehensive overview of the research progress on oxidation behaviors and degradation mechanisms in chromium-coated zirconium alloy cladding under high-temperature *** techniques to strengthen the oxidation resistance are highlighted and ***,challenges and opportunities for various future directions are addressed.

关键词： Accident-tolerant fuel Chromium coating Degradation mechanism High-temperature oxidation behavior Zirconium alloy cladding

Exploring the spatiotemporal heterogeneity of vegetation changes in subtropical humid karst region under CO2 fertilization

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Journal of Geographical Sciences 2025年第1期35卷 65-87页

作者： CHEN Meng ZHOU Qiuwen PENG Dawei YAN Weihong school of Geography and Environmental Science Guizhou Normal University Huanjiang Observation and Research Station for Karst Ecosystem Guangxi Key Laboratory of Karst Ecological Processes and Services Institute of Subtropical Agriculture CAS University of Chinese Academy of Sciences Faculty of Geographical Science Beijing Normal University Forestry Bureau of Shibing County

Terrestrial ecosystems heavily depend on vegetation,which responds to carbon dioxide （CO2） fertilization in hot and humid *** subtropical humid karst region is a hot and humid region;whether and to what extent CO2fertilization affects vegetation changes in such regions remains *** this study,we investigated the degree to which CO2fertilization influences vegetation changes,along with their spatial and temporal differences,in the subtropical humid karst region using time-lag effect analysis,a random forest model,and multiple regression *** showed that CO2fertilization plays an important role in vegetation changes,exhibiting clear spatial variations across different geomorphological zones,with its degree of influence ranging mainly between 11%and 25%.The highest contribution of CO2fertilization was observed in the karst basin and non-karstic region,whereas the lowest contribution was found in the karst plateau *** studies have primarily attributed vegetation changes in subtropical humid karst region to ecological engineering,leading to an overestimation of its contribution to these *** findings of this study enhance the understanding of the mechanism of vegetation changes in humid karst region and provide theoretical and practical insights for ecological and environmental protection in these regions.

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