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High-resolution neutronics model for ^(238)Pu production in high-flux reactors

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nuclear science and Techniques 2024年第5期35卷 226-236页

作者： Qing-Quan Pan Qing-Fei Zhao Lian-Jie Wang Bang-Yang Xia Yun Cai Jin-Biao Xiong Xiao-Jing Liu School of nuclear science and Engineering Shanghai Jiao Tong UniversityShanghai 200240China science and technology on Reactor System Design technology Laboratory Nuclear Power Institute of ChinaChengdu 610200China

We proposed and compared three methods(filter burnup,single energy burnup,and burnup extremum analysis)to build a high-resolution neutronics model for 238Pu production in high-flux *** filter burnup and single energy burnup methods have no theoretical approximation and can achieve a spectrum resolution of up to~1 eV,thereby constructing the importance curve and yield curve of the full energy *** burnup extreme analysis method combines the importance and yield curves to consider the influence of irradiation time on production efficiency,thereby constructing extreme *** three curves,which quantify the transmutation rate of the nuclei in each energy region,are of physical significance because they have similar distributions.A high-resolution neutronics model for ^(238)Pu production was established based on these three curves,and its universality and feasibility were *** neutronics model can guide the neutron spectrum optimization and improve the yield of ^(238)Pu by up to 18.81%.The neutronics model revealed the law of nuclei transmutation in all energy regions with high spectrum resolution,thus providing theoretical support for high-flux reactor design and irradiation production of ^(238)Pu.

关键词： ^(238)Pu Neutronics model High-flux reactor Spectrum resolution Spectrum optimization

Atomistic study on the microscopic mechanism of grain boundary embrittlement induced by small dense helium bubbles in iron

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nuclear science and Techniques 2024年第3期35卷 84-95页

作者： Lei Peng Yong-Jie Sun Jing-Yi Shi Yi-Fei Liu Shang-Ming Chen Liu-Liu Li State Key Laboratory of Particle Detection and Electronics University of Science and Technology of ChinaHefei 230026China School of nuclear science and technology University of Science and Technology of ChinaHefei 230027China science and technology on Reactor System Design technology Laboratory Nuclear Power Institute of ChinaChengdu 610213China

The helium bubbles induced by 14 MeV neutron irradiation can cause intergranular fractures in reduced activation ferritic martensitic steel,which is a candidate structural material for fusion *** order to elucidate the susceptibility of different grain boundaries(GBs)to helium-induced embrittlement,the tensile fracture processes of 10 types of GBs with and without helium bubbles in body-centered cubic(bcc)iron at the relevant service temperature of 600 K were investigated via molecular dynamics *** results indicate that in the absence of helium bubbles,the GBs studied here can be classified into two distinct categories:brittle GBs and ductile *** atomic scale analysis shows that the plastic deformation of ductile GB at high temperatures originates from complex plastic deformation mechanisms,including the Bain/Burgers path phase transition and deformation twinning,in which the Bain path phase transition is the most dominant plastic deformation ***,the presence of helium bubbles severely inhibits the plastic deformation channels of the GBs,resulting in a significant decrease in elongation at *** bubble-decorated GBs,the ultimate tensile strength increases with the increase in the misorientation ***,the coherent twin boundary∑3{112}was found to maintain relatively high fracture strength and maximum failure strain under the influence of helium bubbles.

关键词： Helium bubble Grain boundary Embrittlement Reduced activation ferritic martensitic steel Molecular dynamics Bain path

The biochemical behavior and mechanism of uranium(Ⅵ)bioreduction induced by natural Bacillus thuringiensis

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Journal of Environmental sciences 2024年第2期136卷 372-381页

作者： Shunzhang Chen Junyuan Gong Yanxia Cheng Yuqi Guo Feize Li Tu Lan Yuanyou Yang Jijun Yang Ning Liu Jiali Liao Key Laboratory of Radiation Physics and technology of the Ministry of Education Institute of Nuclear Science and TechnologySichuan UniversityChengdu 610064China

For a broader understanding of uranium migration affected by microorganisms in natural anaerobic environment,the bioreduction of uranium(Ⅵ)(U(Ⅵ))was revealed in Bacillus thuringiensis,a dominant bacterium strain with potential of uranium-tolerant isolated from uranium contaminated *** reduction behavior was systematically investigated by the quantitative analysis of U(Ⅳ)in bacteria,and mechanism was inferred from the pathway of electron *** anaerobic conditions,appropriate biomass and sodium lactate as electron donor,reduction behavior of U(Ⅵ)induced by *** was restricted by the activity of lactate dehydrogenase,which was directly affected by the initial pH,temperature and initial U(Ⅵ)concentration of bioreduction *** of U(Ⅵ)was driven by the generation of nicotinamide adenine dinucleotide(NADH)from enzymatic reaction of sodium lactate with various *** transmission of the electrons from bacteria to U(Ⅵ)was mainly supported by the intracellular NADH dehydrogenase-ubiquinone system,this process could maintain the biological activity of cells.

关键词： Uranium Bacillus thuringiensis Bioreduction Electron transmission

First-principles study on the diffusion behavior of Cs and I in Cr coating

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nuclear science and Techniques 2024年第6期35卷 177-188页

作者： Shu-Ying Lin Xiao-Jing Li Lin-Bing Jiang Xi-Jun Wu Hui-Qin Yin Yu Ma Wen-Guan Liu Sino-French institute of nuclear Engineering and technology Sun Yat-Sen UniversityZhuhai 519082China School of nuclear science and technology University of South ChinaHengyang 421001China

Cs and I can migrate through fuel-cladding interfaces and accelerate the cladding corrosion process induced by the fuel-cladding chemical *** coating has emerged as an important candidate for mitigating this chemical *** this study,first-principles calculations were employed to investigate the diffusion behavior of Cs and I in the Cr bulk and grain boundaries to reveal the microscopic interaction mitigation mechanisms at the fuel-cladding *** interaction between these two fission products and the Cr coating were studied systematically,and the Cs and I temperature-dependent diffusion coefficients in Cr were obtained using Bocquet’s oversized solute-atom model and Le Claire’s nine-frequency model,*** results showed that the Cs and I migration barriers were significantly lower than that of Cr,and the Cs and I diffusion coefficients were more than three orders of magnitude larger than the Cr self-diffusion coefficient within the temperature range of Generation-IV fast reactors(below 1000 K),demonstrating the strong penetration ability of Cs and ***,Cs and I are more likely to diffuse along the grain boundary because of the generally low migration barriers,indicating that the grain boundary serves as a fast diffusion channel for Cs and I.

关键词： First-principles calculation Fuel cladding chemical interaction Cr coating Fission product Diffusion Grain boundary

In situ luminescence measurements of GaN/Al_(2)O_(3) film under different energy proton irradiations

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Chinese Physics B 2024年第5期33卷 704-710页

作者：蒋文丽欧阳潇仇猛淋英敏菊陈琳庞盼张春雷张耀锋廖斌 Key Laboratory of Beam technology of Ministry of Education College of Nuclear Science and TechnologyBeijing Normal UniversityBeijing 100875China institute of Radiation technology Beijing Academy of Science and TechnologyBeijing 100875China

Ion beam-induced luminescence(IBIL) experiments were performed to investigate the in situ luminescence of GaN/Al_(2)O_(3) at varying ion energies,which allowed for the measurement of defects at different depths within the *** energies of H^(+)were set to 500 keV,640 keV and 2 MeV,the Bragg peaks of which correspond to the GaN film,GaN/Al_(2)O_(3) heterojunction and Al_(2)O_(3) substrate,respectively.A photoluminescence measurement at 250 K was also performed for comparison,during which only near band edge(NBE) and yellow band luminescence in the GaN film were *** evolution of the luminescence of the NBE and yellow band in the GaN film was discussed,and both exhibited a decrease with the fluence of H^(+).Additionally,the luminescence of F centers,induced by oxygen vacancies,and Cr^(3+),resulting from the ^(2)E →^(4)A_(2) radiative transition in Al_(2)O_(3),were measured using 2 MeV H^(+).The luminescence intensity of F centers increases gradually with the fluence of H^(+).The luminescence evolution of Cr^(3+)is consistent with a yellow band center,attributed to its weak intensity,and it is situated within the emission band of the yellow band in the GaN *** results show that IBIL measurement can effectively detect the luminescence behavior of multilayer films by adjusting the ion *** measurement can be excited by various techniques,but IBIL can satisfy in situ luminescence measurement,and multilayer structural materials of tens of micrometers can be measured through IBIL by adjusting the energy of the inducing *** evolution of defects at different layers with ion fluence can be obtained.

关键词： ion beam-induced luminescence(IBIL) GaN/Al_(2)O_(3) ion beam

Study of primordial deuterium abundance in Big Bang nucleosynthesis

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nuclear science and Techniques 2024年第3期35卷 208-215页

作者： Zhi-Lin Shen Jian-Jun He Key Laboratory of Beam technology of Ministry of Education College of Nuclear Science and TechnologyBeijing Normal UniversityBeijing 100875China institute of Radiation technology Beijing Academy of Science and TechnologyBeijing 100875China

Big Bang nucleosynthesis(BBN)theory predicts the primordial abundances of the light elements^(2) H(referred to as deuterium,or D for short),^(3)He,^(4)He,and^(7) Li produced in the early *** these,deuterium,the first nuclide produced by BBN,is a key primordial material for subsequent *** date,the uncertainty in predicted deuterium abundance(D/H)remains larger than the observational *** this study,the Monte Carlo simulation code PRIMAT was used to investigate the sensitivity of 11 important BBN reactions to deuterium *** found that the reaction rate uncertainties of the four reactions d(d,n)^(3)He,d(d,p)t,d(p,γ)^(3)He,and p(n,γ)d had the largest influence on the calculated D/H ***,the calculated D/H uncertainty cannot reach observational precision even with the recent LUNA precise d(p,γ)^(3) He *** the nuclear physics aspect,there is still room to largely reduce the reaction-rate uncertainties;hence,further measurements of the important reactions involved in BBN are still necessary.A photodisintegration experiment will be conducted at the Shanghai Laser Electron Gamma Source Facility to precisely study the deuterium production reaction of p(n,γ)d.

关键词： Big Bang nucleosynthesis Abundance of deuterium Reaction cross section Reaction rate Monte Carlo method

Trial application of the envelope method to the potential ambiguity problem

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nuclear science and Techniques 2024年第1期35卷 73-80页

作者： Li-Yuan Hu Yu-Shou Song Fundamental science on nuclear Safety and Simulation technology Laboratory Harbin Engineering UniversityHarbin 150001China College of nuclear science and technology Harbin Engineering UniversityHarbin 150001China Key Laboratory of nuclear Safety and Advanced nuclear Energy technology Ministry of Industry and Information TechnologyHarbin 150001China

The optical potential ambiguity is a long-standing problem in the analysis of elastic scattering *** a specific collid-ing system,ambiguous potential families can lead to different behaviors in the nearside and farside scattering *** contrast,the envelope method can decompose the experimental data into two components with negative and positive deflection angles,***,a question arises as to whether the comparison between the calculated nearside(or farside)component and the derived positive-deflection-angle(or negative-deflection-angle)component can help analyze the potential ambiguity *** this study,we conducted a trial application of the envelope method to the potential ambiguity *** envelope method was improved by including uncertainties in the experimental *** colliding systems of 16O+28Si at 215.2 MeV and 12C+12C at 1016 MeV were considered in the *** each colliding system,the angular distribution experimental data were described nearly equally well by two potential sets,one of which is“surface transpar-ent”and the other is *** calculated angular distributions were decomposed into nearside and farside scattering *** the improved envelope method,the experimental data were decomposed into the positive-deflection-angle and negative-deflection-angle components,which were then compared with the calculated nearside and farside *** capability of the envelope method to analyze the potential ambiguities was also discussed.

关键词： Elastic scattering Optical potential ambiguities Envelope method Nearside/farside decomposition

Optical design of a novel near-infrared phase contrast imaging(NI-PCI)diagnostic on the HL-2A tokamak

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Plasma science and technology 2024年第3期26卷 31-37页

作者：徐皓龚少博余羿许敏兰涛王志斌石中兵聂林赵光义刘灏周艺轩袁子豪肖晨雨陈坚 Sino-French institute of nuclear Engineering and technology Sun Yat-sen UniversityZhuhai 519082People's Republic of China Southwestern institute of Physics Chengdu 610041People's Republic of China School of nuclear science and technology University of Science and Technology of ChinaHefei 230026People's Republic of China

The optical design of near-infrared phase contrast imaging(NI-PCI)diagnosis on HL-2A is introduced in this *** scheme benefits from the great progress of near-infrared laser technology and is a broadening of traditional phase contrast *** diagnostic can work as a keen tool to measure plasma wavenumber spectra by inferring string-integrated plasma density *** of both the front optical path which is the path before the laser transmitting into the tokamak plasma and the rear optics which is the path after the laser passing through the plasma is *** 1550 nm laser is chosen as the probe beam and highprecision optical components are designed to fit the laser beam,in which a phase plate with a 194-nm-deep silver groove is the *** with the conventional 10.6μm laser-based PCI system on HL-2A,NI-PCI significantly overcomes the unwanted phase scintillation effect and promotes the measurement capability of high-wavenumber turbulence with an increased maximal measurable wavenumber from 15 cm^(-1)to 32.6 cm^(-1).

关键词： phase contrast imaging near infrared laser plasma laser diagnostic

Studies of an event-building algorithm of the readout system for the twin TPCs in HFRS

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nuclear science and Techniques 2024年第4期35卷 82-95页

作者： Jing Tian Zhi-Peng Sun Song-Bo Chang Yi Qian Hong-Yun Zhao Zheng-Guo Hu Xi-Meng Chen institute of Modern Physics Chinese Academy of SciencesLanzhou 730000China School of nuclear science and technology University of LanzhouLanzhou 730000China School of nuclear science and technology University of Chinese Academy of SciencesBeijing 100049China Advanced Energy science and technology Guangdong LaboratoryHuizhou 516000China

The High-energy Fragment Separator(HFRS),which is currently under construction,is a leading international radioactive beam *** sets of position-sensitive twin time projection chamber(TPC)detectors are distributed on HFRS for particle identification and beam *** twin TPCs'readout electronics system operates in a trigger-less mode due to its high counting rate,leading to a challenge of handling large amounts of *** address this problem,we introduced an event-building *** algorithm employs a hierarchical processing strategy to compress data during transmission and *** addition,it reconstructs twin TPCs'events online and stores only the reconstructed particle information,which significantly reduces the burden on data transmission and storage *** studies demonstrated that the algorithm accurately matches twin TPCs'events and reduces more than 98%of the data volume at a counting rate of 500 kHz/channel.

关键词： High counting rate Twin TPCs Trigger-less Readout electronics Event building Hierarchical data processing