Molten salt reactors,being the only reactor type among Generation Ⅳ advanced nuclear reactors that utilize liquid fuels,offer inherent safety,high-temperature,and low-pressure operation,as well as the capability for ...Molten salt reactors,being the only reactor type among Generation Ⅳ advanced nuclear reactors that utilize liquid fuels,offer inherent safety,high-temperature,and low-pressure operation,as well as the capability for online fuel reprocessing.However,the fuel-salt flow results in the decay of delayed neutron precursors(DNPs)outside the core,causing fluctuations in the effective delayed neutron fraction and consequently impacting the reactor reactivity.Particularly in accident scenarios—such as a combined pump shutdown and the inability to rapidly scram the reactor—the sole reliance on negative temperature feedback may cause a significant increase in core temperature,posing a threat to reactor safety.To address these problems,this paper introduces an innovative design for a passive fluid-driven suspended control rod(SCR)to dynamically compensate for reactivity fluctuations caused by DNPs flowing with the fuel.The control rod operates passively by leveraging the combined effects of gravity,buoyancy,and fluid dynamic forces,thereby eliminating the need for an external drive mechanism and enabling direct integration within the active region of the core.Using a 150 MWt thorium-based molten salt reactor as the reference design,we develop a mathematical model to systematically analyze the effects of key parameters—including the geometric dimensions and density of the SCR—on its performance.We examine its motion characteristics under different core flow conditions and assess its feasibility for the dynamic compensation of reactivity changes caused by fuel flow.The results of this study demonstrate that the SCR can effectively counteract reactivity fluctuations induced by fuel flow within molten salt reactors.A sensitivity analysis reveals that the SCR’s average density exerts a profound impact on its start-up flow threshold,channel flow rate,resistance to fuel density fluctuations,and response characteristics.This underscores the critical need to optimize this parameter.Moreover,by judiciously selecting the SCR’s length,number of deployed units,and the placement we can achieve the necessary reactivity control while maintaining a favorable balance between neutron economy and heat transfer performance.Ultimately,this paper provides an innovative solution for the passive reactivity control in molten salt reactors,offering significant potential for practical engineering applications.展开更多
Small modular reactor(SMR)belongs to the research forefront of nuclear reactor technology.Nowadays,advancement of intelligent control technologies paves a new way to the design and build of unmanned SMR.The autonomous...Small modular reactor(SMR)belongs to the research forefront of nuclear reactor technology.Nowadays,advancement of intelligent control technologies paves a new way to the design and build of unmanned SMR.The autonomous control process of SMR can be divided into three stages,say,state diagnosis,autonomous decision-making and coordinated control.In this paper,the autonomous state recognition and task planning of unmanned SMR are investigated.An operating condition recognition method based on the knowledge base of SMR operation is proposed by using the artificial neural network(ANN)technology,which constructs a basis for the state judgment of intelligent reactor control path planning.An improved reinforcement learning path planning algorithm is utilized to implement the path transfer decision-makingThis algorithm performs condition transitions with minimal cost under specified modes.In summary,the full range control path intelligent decision-planning technology of SMR is realized,thus provides some theoretical basis for the design and build of unmanned SMR in the future.展开更多
Under the dual-carbon background,the technological updating of traditional high-energy-consuming equipment should not be delayed,and the problem of reactor energy consumption should not be ignored.Therefore,this study...Under the dual-carbon background,the technological updating of traditional high-energy-consuming equipment should not be delayed,and the problem of reactor energy consumption should not be ignored.Therefore,this study is based on computational fluid dynamics(CFD)theory to simulate the spiral stirred reactor with different design parameters(distance of paddle from bottom surface to reactor height ratio h1/H,diameter of stirring paddle to reactor diameter ratio Ds/D,length of blade section to reactor height ratio Ls/H).It was found that the reactor designed with lower Ls/H values and higher h1/H,Ds/D values would have smaller power number(Np)values and smaller flow field average velocity.In addition,this study also fitted the correlation equation of Np concerning Reynolds number and h1/H,Ds/D,and Ls/H,and the conclusions of the study can be used as a reference for the design of industrial equipment.展开更多
Electrochemical CO_(2) reduction(ECR)driven by intermittent renewable energy sources is an emerging technology to achieve net-zero CO_(2) emissions.Tandem electrochemical CO_(2) reduction(T-ECR),employs tandem catalys...Electrochemical CO_(2) reduction(ECR)driven by intermittent renewable energy sources is an emerging technology to achieve net-zero CO_(2) emissions.Tandem electrochemical CO_(2) reduction(T-ECR),employs tandem catalysts with synergistic or complementary functions to efficiently convert CO_(2) into multi-carbon(C^(2+))products in a succession of reactions within single or sequentially coupled reactors.However,the lack of clear interpretation and systematic understanding of T-ECR mechanisms has resulted in suboptimal current outcomes.This review presents new perspectives and summarizes recent advancements in efficient T-ECR across various scales,including synergistic tandem catalysis at the microscopic scale,relay tandem catalysis at the mesoscopic scale,and tandem reactors at the macroscopic scale.We begin by outlining the principle of tandem catalysis,followed by discuss on tandem catalyst design,the electrode construction,and reactor configuration.Additionally,we address the challenges and prospects of tandem strategies,emphasizing the integration of machine learning,theoretical calculations,and advanced characterization techniques for developing industry-scale CO_(2) valorization.展开更多
In response to the accelerating demands of industrial development,the scale-up of stirred reactors has become increasingly prevalent.Multi-shaft stirred reactors have emerged as a promising solution;however,a critical...In response to the accelerating demands of industrial development,the scale-up of stirred reactors has become increasingly prevalent.Multi-shaft stirred reactors have emerged as a promising solution;however,a critical challenge remains in achieving efficient mixing while simultaneously minimizing energy consumption.Here,a novel approach based on differential rotation speeds to optimize mixing performance was proposed.Results demonstrate that a carefully configured rotation speed difference significantly enhances mixing efficiency,reducing mixing time by 17.89% and power consumption by 12.07%.This strategy not only amplifies flow field instability but also minimizes instability discrepancies,promoting a more uniform distribution of vortices across various scales.Furthermore,under this approach,the bottom impeller has the strongest impact on mixing,while the middle and lower impellers synergistically strengthen the weaker mixing regions and facilitate the redistribution of energy in the flow field.This method promotes efficient energy transfer from large-scale to small-scale vortices,ultimately improving overall mixing performance.This work offers a promising avenue for the optimal design and operation of multi-shaft stirred reactors,advancing both efficiency and energy sustainability.展开更多
The advancement of clean electricity is positioning electrochemical reactors at the forefront of future electrosynthesis technologies.Solid-state electrolyte(SSE)reactors emerge for their distinctive configurations an...The advancement of clean electricity is positioning electrochemical reactors at the forefront of future electrosynthesis technologies.Solid-state electrolyte(SSE)reactors emerge for their distinctive configurations and ability to produce high-purity fuels and chemicals efficiently without additional purification steps.This marks a substantial development in electrochemical synthesis.In this perspective,we critically examine cutting-edge innovations in SSE devices with particular emphasis on the architectural introduction of core cell components,novel electrochemical cell configurations,and assembly methodologies.The use of SSE reactors is presently undergoing a pivotal transition from fundamental laboratory investigations to large-scale engineering implementations,demonstrating remarkable progress in multiple domains:(1)sustainable synthesis of high-value organic acids(formic and acetic acids),(2)production of critical oxidizers hydrogen peroxide(H_(2)O_(2))and liquid fuels(ethanol),(3)ammonia(NH_(3))production,(4)carbon capture technologies,(5)lithium recovery and recycling,and(6)tandem or coupling strategies for high-value-added products.Importantly,the transformative potential in environmental remediation,particularly for airborne pollutant sequestration and advanced wastewater purification,is addressed.Additionally,the innovative architectural blueprints for next-generation SSE stack are presented,aiming to establish a comprehensive framework to guide the transition from laboratory-scale innovation to industrial-scale deployment of SSE devices in the foreseeable future.展开更多
High flux reactors(HFRs)are a special type of research reactor aimed at providing a high neutron flux.Compared with power reactors and other research reactors,HFRs have unique technical features in terms of reactor co...High flux reactors(HFRs)are a special type of research reactor aimed at providing a high neutron flux.Compared with power reactors and other research reactors,HFRs have unique technical features in terms of reactor core design,irradiation capability,and operating characteristics.They can be applied to the irradiation tests of nuclear fuels and materials,radioisotope production,neutron science,and experiments.This paper reviews HFRs,including their development history,technical features,and application areas,as well as trends in the development of new and advanced HFRs.展开更多
Molten salt reactors(MSRs)are a promising candidate for Generation IV reactor technologies,and the small modular molten salt reactor(SM-MSR),which utilizes low-enriched uranium and thorium fuels,is regarded as a wise ...Molten salt reactors(MSRs)are a promising candidate for Generation IV reactor technologies,and the small modular molten salt reactor(SM-MSR),which utilizes low-enriched uranium and thorium fuels,is regarded as a wise development path to accelerate deployment time.Uncertainty and sensitivity analyses of accidents guide nuclear reactor design and safety analyses.Uncertainty analysis can ascertain the safety margin,and sensitivity analysis can reveal the correlation between accident consequences and input parameters.Loss of forced cooling(LOFC)represents an accident scenario of the SM-MSR,and the study of LOFC could offer useful information to improve physical thermohydraulic and structural designs.Therefore,this study investigates the uncertainty of LOFC consequences and the sensitivity of related parameters.The uncertainty of the LOFC consequences was analyzed using the Monte Carlo method,and multiple linear regression was employed to analyze the sensitivity of the input parameters.The uncertainty and sensitivity analyses showed that the maximum reactor outlet fuel salt temperature was 725.5℃,which is lower than the acceptable criterion,and five important parameters influencing LOFC consequences were identified.展开更多
Paired electrosynthesis has received considerable attention as a consequence of simultaneously synthesizing target products at both cathode and anode,whereas the related synthetic efficiency in batch reactors is still...Paired electrosynthesis has received considerable attention as a consequence of simultaneously synthesizing target products at both cathode and anode,whereas the related synthetic efficiency in batch reactors is still undesirable under certain circumstances.Encouragingly,laminar microfluidic reactor offers prospective options that possess controllable flow characteristics such as enhanced mass transport,precise laminar flow control and the ability to expand production scale progressively.In this comprehensive review,the underlying fundamentals of the paired electrosynthesis are initially summarized,followed by categorizing the paired electrosynthesis including parallel paired electrosynthesis,divergent paired electrosynthesis,convergent paired electrosynthesis,sequential paired electrosynthesis and linear paired electrosynthesis.Thereafter,a holistic overview of microfluidic reactor equipment,integral fundamentals and research methodology as well as channel extension and scale-up strategies is proposed.The established fundamentals and evaluated metrics further inspired the applications of microfluidic reactors in paired electrosynthesis.This work stimulated the overwhelming investigation of mechanism discovery,material screening strategies,and device assemblies.展开更多
Leveraging big data signal processing offers a pathway to the development of artificial intelligencedriven equipment.The analysis of fluid flow signals and the characterization of fluid flow behavior are of critical i...Leveraging big data signal processing offers a pathway to the development of artificial intelligencedriven equipment.The analysis of fluid flow signals and the characterization of fluid flow behavior are of critical in two-phase flow studies.Significant research efforts have focused on discerning flow regimes using various signal analysis methods.In this review,recent advances in time series signals analysis algorithms for stirred tank reactors have been summarized,and the detailed methodologies are categorized into the frequency domain methods,time-frequency domain methods,and state space methods.The strengths,limitations,and notable findings of each algorithm are highlighted.Additionally,the interrelationships between these methodologies have also been discussed,as well as the present progress achieved in various applications.Future research directions and challenges are also predicted to provide an overview of current research trends in data mining of time series for analyzing flow regimes and chaotic signals.This review offers a comprehensive summary for extracting and characterizing fluid flow behavior and serves as a theoretical reference for optimizing the characterization of chaotic signals in future research endeavors.展开更多
The formation,evolution and modelling of organized flow structures(e.g.,segregated regions and centre-surface vortices) and their destruction in unbaffled stirred tank reactors(UBSTRs) have been a hot research topic i...The formation,evolution and modelling of organized flow structures(e.g.,segregated regions and centre-surface vortices) and their destruction in unbaffled stirred tank reactors(UBSTRs) have been a hot research topic in the field of fluid mixing.In this paper,the relevant researches in the past 30 years were reviewed,focusing on the application of asymmetric mixing.In particular,by drawing on chaotic phenomena in nature and human society(e.g.,kneading-dough,traffic flow,frightened school of fish),we propose a fluid mixing mechanism:squeezing-induced chaotic mixing,and further propose a bionics-imitation-simulation design concept for UBSTRs.This concept is also an important inspiration for the design of other chemical reactors.展开更多
Artificial intelligence has potential for forecasting reactor conditions in the nuclear industry.Owing to economic and security concerns,a common method is to train data generated by simulators.However,achieving a sat...Artificial intelligence has potential for forecasting reactor conditions in the nuclear industry.Owing to economic and security concerns,a common method is to train data generated by simulators.However,achieving a satisfactory performance in practical applications is difficult because simulators imperfectly emulate reality.To bridge this gap,we propose a novel framework called simulation-to-reality domain adaptation(SRDA)for forecasting the operating parameters of nuclear reactors.The SRDA model employs a transformer-based feature extractor to capture dynamic characteristics and temporal dependencies.A parameter predictor with an improved logarithmic loss function is specifically designed to adapt to varying reactor powers.To fuse prior reactor knowledge from simulations with reality,the domain discriminator utilizes an adversarial strategy to ensure the learning of deep domain-invariant features,and the multiple kernel maximum mean discrepancy minimizes their discrepancies.Experiments on neutron fluxes and temperatures from a pressurized water reactor illustrate that the SRDA model surpasses various advanced methods in terms of predictive performance.This study is the first to use domain adaptation for real-world reactor prediction and presents a feasible solution for enhancing the transferability and generalizability of simulated data.展开更多
Accurate water level measurement in nuclear reactors,particularly in PWRs(pressurized water reactors)and BWRs(boiling water reactors),is essential for ensuring the safety and efficiency of reactor operations.K-type HJ...Accurate water level measurement in nuclear reactors,particularly in PWRs(pressurized water reactors)and BWRs(boiling water reactors),is essential for ensuring the safety and efficiency of reactor operations.K-type HJTCs(heated junction thermocouples)are widely used for this purpose due to their ability to withstand extreme temperatures and radiation conditions.This article explores the role of HJTCs in reactor water level measurement and compares the performance of 2-wire and 3-wire connections.While the 2-wire connection is simple and cost-effective,it can introduce measurement inaccuracies due to wire resistance.In contrast,the 3-wire connection compensates for lead resistance,offering more precise and reliable measurements,particularly in long-distance applications.This paper discusses the operational considerations of these wiring configurations in the context of nuclear reactors and highlights the importance of choosing the appropriate connection type to optimize safety and measurement accuracy in PWR and BWR reactors.展开更多
Knowing the precise relationship between fuel loading and reactivity is essential for guiding reactor criticality extrapolation and online refueling in molten salt reactors(MSRs).This study aims to explore and explain...Knowing the precise relationship between fuel loading and reactivity is essential for guiding reactor criticality extrapolation and online refueling in molten salt reactors(MSRs).This study aims to explore and explain the linear relationship between reactivity and the reciprocal of uranium concentration in thermal-spectrum MSRs.By applying neutron balance theory,we analyzed the neutron absorption cross sections of various nuclides in single-lattice models with varying fuel concentrations.Our findings reveal a simple linear correlation between reactivity and the reciprocal of uranium concentration,which can be explained from the perspective of nuclear reaction cross sections that adhere to the 1/v law in the thermal neutron spectrum.Furthermore,we identified that the neutron absorption single-group cross sections of structural materials and carrier salts exhibit an approximately linear relationship with the fission single-group cross section of ^(235) U;similarly,the reciprocal of ^(235)U’s fission cross section exhibits an approximately linear relationship with uranium concentration.This linear relationship deviates as the volume fraction of molten salt increases,due to a greater proportion of neutrons being captured in the resonance energy spectrum.However,it remains valid for molten salt volume fractions up to 25%and demonstrates broad applicability in the physical design and operation of thermal molten salt reactors.展开更多
Subcritical reactors(SCRs)or subcritical assemblies(SCAs)are the main infrastructure for designing power reactors.These reactors are widely used for training and research because of their high level of inherent safety...Subcritical reactors(SCRs)or subcritical assemblies(SCAs)are the main infrastructure for designing power reactors.These reactors are widely used for training and research because of their high level of inherent safety.The objective of this study is to design a subcritical reactor using a pressurized water reactor(PWR)conventional fuel following two safety points.In the first approach,deeply placed SCR cores with an infinite multiplication factor(k_(∞))of less than unity were identified using the DRAGON lattice code.In the second approach,subcritical reactor cores with an effective multiplication factor(k_(eff))of less than unity were determined by coupling the cell calculations of the DRAGON lattice code and core calculations of the DONJON code.For the deeply subcritical reactor design,it was found that the reactor would remain inherently subcritical while using fuel rods with ^(235)U enrichment of up to 0.9%,regardless of the pitch of the fuel rods.In the second approach,the optimal pitches(1.3 to 2.3 cm)were determined for different fuel enrichment values from 1 to 5%.Subsequently,the k_(eff) was obtained for a fuel rod arrangement of 8×8 to 80×80,and the states in which the reactor would be subcritical were determined for different fuel enrichments at the corresponding optimal pitch.To validate the models used in the DRAGON and DONJON codes,the k_(eff) of the Isfahan Light Water Subcritical Reactor(LWSCR)was experimentally measured and compared with the results of the calculations.Finally,the effects of fuel and moderator temperature changes were investigated to ensure that the designed assemblies remained in the subcritical state at all operational temperatures.展开更多
From an engineering feasibility standpoint, what level of performance metrics can be ultimately achieved when designing a reactor using well-established nuclear fuels and structural materials that have already undergo...From an engineering feasibility standpoint, what level of performance metrics can be ultimately achieved when designing a reactor using well-established nuclear fuels and structural materials that have already undergone irradiation testing? The irradiation capability, which hinges on parameters like neutron flux level, irradiation channels' volume, and fuel cycle duration, is a core indicator for high-flux reactors. We propose a conceptual design of an ultra-high flux fast reactor(UFFR) with strong irradiation capability, which utilizes U-20Pu-10Zr alloy fuel and employs lead-bismuth as the coolant. The maximum neutron flux in the core reaches 1.32×10^(16) cm^(-2)s^(-1), while the average neutron flux in the irradiation channels attains 1.19×10^(16) cm^(-2)s^(-1). The volume of the central irradiation channel exceeds 10000 cm^(3), and the fuel cycle duration is 165 d, placing all its performance indicators among the top in the world. Based on the analyses of reactor physics and thermalhydraulics, it has been demonstrated that all reactivity coefficients are negative and all physical parameters meet the design criteria, ensuring the inherent safety of UFFR. An assessment of the irradiation capability has been carried out based on californium-252(^(252)Cf) production, indicating that the irradiation capability of UFFR surpasses that of the high flux isotope reactor(HFIR). The yield of ^(252)Cf from UFFR is 14.39 times that of HFIR, and its nuclei conversion rate is 3.21 times that of HFIR.展开更多
A low-temperature-resistant and high-strength stainless-steel jacket is a key component in the superconducting magnet of a fusion reactor.The development of cryogenic structural materials with high strength and toughn...A low-temperature-resistant and high-strength stainless-steel jacket is a key component in the superconducting magnet of a fusion reactor.The development of cryogenic structural materials with high strength and toughness poses a challenge for the future development of high-field superconducting magnets in fusion reactors.The yield strength of the International Thermonuclear Experimental Reactor developed for low-temperature structural materials at 4.2K is below 1100MPa,which fails to meet the demand for structural components with yield strengths exceeding 1500MPa at 4.2K in the future fusion reactors.CHSN01(formerly N50H),which is a low-temperature structural material developed in China,exhibits exceptional strength and toughness,thereby making it highly promising for practical applications.Recently,a 30 t jacket measuring approximately 5000m in total length was produced.Its low-temperature mechanical properties were tested using a sampling method to ensure compliance with application requirements.This paper presents the experimental data of the CHSN01 jacket and tests of the physical properties of the material in the temperature range of 4–300 K.The physical properties were unaffected by magnetic field.Furthermore,this paper discusses the feasibility of employing CHSN01 as a cryogenic structural material capable of withstanding high magnetic fields in next-generation fusion reactors.展开更多
Laser-induced aerosols,predominantly submicron in size,pose significant environmental and health risks during the decommissioning of nuclear reactors.This study experimentally investigated the removal of laser-generat...Laser-induced aerosols,predominantly submicron in size,pose significant environmental and health risks during the decommissioning of nuclear reactors.This study experimentally investigated the removal of laser-generated aerosol particles using a water spray system integrated with an innovative system for pre-injecting electrically charged mist in our facility.To simulate aerosol generation in reactor decommissioning,a high-power laser was used to irradiate various materials(including stainless steel,carbon steel,and concrete),generating aerosol particles that were agglomerated with injected water mist and subsequently scavenged by water spray.Experimental results demonstrate enhanced aerosol removal via aerosol-mist agglomeration,with charged mist significantly improving particle capture by increasing wettability and size.The average improvements for the stainless steel,carbon steel,and concrete were 40%,44%,and 21%,respectively.The results of experiments using charged mist with different polarities(both positive and negative)and different surface coatings reveal that the dominant polarity of aerosols varies with the irradiated materials,influenced by their crystal structure and electron emission properties.Notably,surface coatings such as ZrO_(2)and CeO_(2)were found to possibly alter aerosol charging characteristics,thereby affecting aerosol removal efficiency with charged mist configurations.The innovative aerosol-mist agglomeration approach shows promise in mitigating radiation exposure,ensuring environmental safety,and reducing contaminated water during reactor dismantling.This study contributes critical knowledge for the development of advanced aerosol management strategies for nuclear reactor decommissioning.The understanding obtained in this work is also expected to be useful for various environmental and chemical engineering applications such as gas decontamination,air purification,and pollution control.展开更多
The synthesis of propylene carbonate(PC)from CO_(2) and propylene oxide(PO)is a typical gas-liquid biphasic system,where gas-liquid mass transfer efficiency significantly influences CO_(2) cycloaddition reactions.Here...The synthesis of propylene carbonate(PC)from CO_(2) and propylene oxide(PO)is a typical gas-liquid biphasic system,where gas-liquid mass transfer efficiency significantly influences CO_(2) cycloaddition reactions.Here,we proposed a microchannel reaction system for the CO_(2) cycloaddition reaction catalyzed by ionic liquid within an aqueous environment.The effect of liquid flow rate,temperature and residence time on gas-liquid flow pattern,catalytic performance and mass transfer were systematically investigated.The results revealed that the PC generation rate reached 560.11 mmol·ml^(−1)·h^(−1)at a 50 cm of flow distance under reaction conditions of 105℃,2.5 MPa,QG=176 ml·min^(−1) and QL=0.3 ml·min^(−1).Variations in mass transfer rate and reaction rate at different flow distances were experimentally studied.The reaction efficiency gradually decreased with increasing flow distance,which were attributed to the reduction of mass transfer caused by decreasing bubble velocity.Optimizing bubble velocity at an appropriate position enhanced reaction efficiency by improving mass transfer,achieving a 97.7%PC yield within 2.85 min.Furthermore,a kinetic model coupling intrinsic kinetics with gas-liquid mass transfer was developed for CO_(2) cycloaddition reaction.The kinetic model was applied to predict PC reaction rates in microchannel reactors at various temperatures and liquid flow rates,achieving an average relative error of 9.6%.展开更多
基金supported by Youth Innovation Promotion Association of Chinese Academy of Sciences(No.2020261)Strategic Priority Research Program of Chinese Academy of Sciences(No.XDA02010000)the Young Potential Program of Shanghai Institute of Applied Physics,Chinese Academy of Sciences(No.SINAP-YXJH-202412).
文摘Molten salt reactors,being the only reactor type among Generation Ⅳ advanced nuclear reactors that utilize liquid fuels,offer inherent safety,high-temperature,and low-pressure operation,as well as the capability for online fuel reprocessing.However,the fuel-salt flow results in the decay of delayed neutron precursors(DNPs)outside the core,causing fluctuations in the effective delayed neutron fraction and consequently impacting the reactor reactivity.Particularly in accident scenarios—such as a combined pump shutdown and the inability to rapidly scram the reactor—the sole reliance on negative temperature feedback may cause a significant increase in core temperature,posing a threat to reactor safety.To address these problems,this paper introduces an innovative design for a passive fluid-driven suspended control rod(SCR)to dynamically compensate for reactivity fluctuations caused by DNPs flowing with the fuel.The control rod operates passively by leveraging the combined effects of gravity,buoyancy,and fluid dynamic forces,thereby eliminating the need for an external drive mechanism and enabling direct integration within the active region of the core.Using a 150 MWt thorium-based molten salt reactor as the reference design,we develop a mathematical model to systematically analyze the effects of key parameters—including the geometric dimensions and density of the SCR—on its performance.We examine its motion characteristics under different core flow conditions and assess its feasibility for the dynamic compensation of reactivity changes caused by fuel flow.The results of this study demonstrate that the SCR can effectively counteract reactivity fluctuations induced by fuel flow within molten salt reactors.A sensitivity analysis reveals that the SCR’s average density exerts a profound impact on its start-up flow threshold,channel flow rate,resistance to fuel density fluctuations,and response characteristics.This underscores the critical need to optimize this parameter.Moreover,by judiciously selecting the SCR’s length,number of deployed units,and the placement we can achieve the necessary reactivity control while maintaining a favorable balance between neutron economy and heat transfer performance.Ultimately,this paper provides an innovative solution for the passive reactivity control in molten salt reactors,offering significant potential for practical engineering applications.
文摘Small modular reactor(SMR)belongs to the research forefront of nuclear reactor technology.Nowadays,advancement of intelligent control technologies paves a new way to the design and build of unmanned SMR.The autonomous control process of SMR can be divided into three stages,say,state diagnosis,autonomous decision-making and coordinated control.In this paper,the autonomous state recognition and task planning of unmanned SMR are investigated.An operating condition recognition method based on the knowledge base of SMR operation is proposed by using the artificial neural network(ANN)technology,which constructs a basis for the state judgment of intelligent reactor control path planning.An improved reinforcement learning path planning algorithm is utilized to implement the path transfer decision-makingThis algorithm performs condition transitions with minimal cost under specified modes.In summary,the full range control path intelligent decision-planning technology of SMR is realized,thus provides some theoretical basis for the design and build of unmanned SMR in the future.
基金supported by the Natural Science Foundation of Shandong Province(ZR2023ZD22)the Major Research and Development Program of Shandong Province(2023CXGC010601).
文摘Under the dual-carbon background,the technological updating of traditional high-energy-consuming equipment should not be delayed,and the problem of reactor energy consumption should not be ignored.Therefore,this study is based on computational fluid dynamics(CFD)theory to simulate the spiral stirred reactor with different design parameters(distance of paddle from bottom surface to reactor height ratio h1/H,diameter of stirring paddle to reactor diameter ratio Ds/D,length of blade section to reactor height ratio Ls/H).It was found that the reactor designed with lower Ls/H values and higher h1/H,Ds/D values would have smaller power number(Np)values and smaller flow field average velocity.In addition,this study also fitted the correlation equation of Np concerning Reynolds number and h1/H,Ds/D,and Ls/H,and the conclusions of the study can be used as a reference for the design of industrial equipment.
文摘Electrochemical CO_(2) reduction(ECR)driven by intermittent renewable energy sources is an emerging technology to achieve net-zero CO_(2) emissions.Tandem electrochemical CO_(2) reduction(T-ECR),employs tandem catalysts with synergistic or complementary functions to efficiently convert CO_(2) into multi-carbon(C^(2+))products in a succession of reactions within single or sequentially coupled reactors.However,the lack of clear interpretation and systematic understanding of T-ECR mechanisms has resulted in suboptimal current outcomes.This review presents new perspectives and summarizes recent advancements in efficient T-ECR across various scales,including synergistic tandem catalysis at the microscopic scale,relay tandem catalysis at the mesoscopic scale,and tandem reactors at the macroscopic scale.We begin by outlining the principle of tandem catalysis,followed by discuss on tandem catalyst design,the electrode construction,and reactor configuration.Additionally,we address the challenges and prospects of tandem strategies,emphasizing the integration of machine learning,theoretical calculations,and advanced characterization techniques for developing industry-scale CO_(2) valorization.
基金supported by the National Natural Science Foundation of China (22078030,52021004)National Key Research and Development Project (2019YFC1905802)+4 种基金Key Project of Independent Research Project of State Key Laboratory of Coal Mine Disaster Dynamics and Control (2011DA105287-zd201902)Chongqing Natural Science Foundation Innovation and Development Joint Fund Project (CSTB2022NSCQ-LZX0014)Hubei Three Gorges Laboratory Open/Innovation Fund (SK211009,SK215001)Fundamental Research Funds for Central Universities(2022CDJQY-005)this work also received funding from the China Scholarship Council。
文摘In response to the accelerating demands of industrial development,the scale-up of stirred reactors has become increasingly prevalent.Multi-shaft stirred reactors have emerged as a promising solution;however,a critical challenge remains in achieving efficient mixing while simultaneously minimizing energy consumption.Here,a novel approach based on differential rotation speeds to optimize mixing performance was proposed.Results demonstrate that a carefully configured rotation speed difference significantly enhances mixing efficiency,reducing mixing time by 17.89% and power consumption by 12.07%.This strategy not only amplifies flow field instability but also minimizes instability discrepancies,promoting a more uniform distribution of vortices across various scales.Furthermore,under this approach,the bottom impeller has the strongest impact on mixing,while the middle and lower impellers synergistically strengthen the weaker mixing regions and facilitate the redistribution of energy in the flow field.This method promotes efficient energy transfer from large-scale to small-scale vortices,ultimately improving overall mixing performance.This work offers a promising avenue for the optimal design and operation of multi-shaft stirred reactors,advancing both efficiency and energy sustainability.
基金support from the Research Grants Council of the Hong Kong Special Administrative Region,China(Project No.PolyU25213824)Hong Kong Polytechnic University(WZ4Q,CDBZ,CE2Y)+3 种基金the National Natural Science Foundation of China(22205187)Shenzhen Municipal Science and Technology Innovation Commission(JCYJ20230807140402006)Department of Science and Technology of Guangdong Province(2023A1515110123,2024A1515012390)MTR Research Funding Scheme(PTU-24028).
文摘The advancement of clean electricity is positioning electrochemical reactors at the forefront of future electrosynthesis technologies.Solid-state electrolyte(SSE)reactors emerge for their distinctive configurations and ability to produce high-purity fuels and chemicals efficiently without additional purification steps.This marks a substantial development in electrochemical synthesis.In this perspective,we critically examine cutting-edge innovations in SSE devices with particular emphasis on the architectural introduction of core cell components,novel electrochemical cell configurations,and assembly methodologies.The use of SSE reactors is presently undergoing a pivotal transition from fundamental laboratory investigations to large-scale engineering implementations,demonstrating remarkable progress in multiple domains:(1)sustainable synthesis of high-value organic acids(formic and acetic acids),(2)production of critical oxidizers hydrogen peroxide(H_(2)O_(2))and liquid fuels(ethanol),(3)ammonia(NH_(3))production,(4)carbon capture technologies,(5)lithium recovery and recycling,and(6)tandem or coupling strategies for high-value-added products.Importantly,the transformative potential in environmental remediation,particularly for airborne pollutant sequestration and advanced wastewater purification,is addressed.Additionally,the innovative architectural blueprints for next-generation SSE stack are presented,aiming to establish a comprehensive framework to guide the transition from laboratory-scale innovation to industrial-scale deployment of SSE devices in the foreseeable future.
文摘High flux reactors(HFRs)are a special type of research reactor aimed at providing a high neutron flux.Compared with power reactors and other research reactors,HFRs have unique technical features in terms of reactor core design,irradiation capability,and operating characteristics.They can be applied to the irradiation tests of nuclear fuels and materials,radioisotope production,neutron science,and experiments.This paper reviews HFRs,including their development history,technical features,and application areas,as well as trends in the development of new and advanced HFRs.
基金supported by the Youth Innovation Promotion Association(YIPA)(No.E329290101)of the Chinese Academy of Sciences。
文摘Molten salt reactors(MSRs)are a promising candidate for Generation IV reactor technologies,and the small modular molten salt reactor(SM-MSR),which utilizes low-enriched uranium and thorium fuels,is regarded as a wise development path to accelerate deployment time.Uncertainty and sensitivity analyses of accidents guide nuclear reactor design and safety analyses.Uncertainty analysis can ascertain the safety margin,and sensitivity analysis can reveal the correlation between accident consequences and input parameters.Loss of forced cooling(LOFC)represents an accident scenario of the SM-MSR,and the study of LOFC could offer useful information to improve physical thermohydraulic and structural designs.Therefore,this study investigates the uncertainty of LOFC consequences and the sensitivity of related parameters.The uncertainty of the LOFC consequences was analyzed using the Monte Carlo method,and multiple linear regression was employed to analyze the sensitivity of the input parameters.The uncertainty and sensitivity analyses showed that the maximum reactor outlet fuel salt temperature was 725.5℃,which is lower than the acceptable criterion,and five important parameters influencing LOFC consequences were identified.
基金supported by the National Natural Science Foundation of China(22178361,22378402,52302310)the International Partnership Project of CAS(039GJHZ2022029GC)+5 种基金the National Key R&D Program of China(2020YFA0710200)the foundation of the Innovation Academy for Green Manufacture Institute,Chinese Academy of Sciences(IAGM2022D07)the China Postdoctoral Science Foundation(2022M722597)QinChuangYuan Cites High-level Innovation and Entrepreneurship Talent Programs(QCYRCXM-2022-335)the Fundamental Research Funds for the Central Universities(G2022KY05111)the Open Project Program of Anhui Province International Research Center on Advanced Building Materials(JZCL2303KF)。
文摘Paired electrosynthesis has received considerable attention as a consequence of simultaneously synthesizing target products at both cathode and anode,whereas the related synthetic efficiency in batch reactors is still undesirable under certain circumstances.Encouragingly,laminar microfluidic reactor offers prospective options that possess controllable flow characteristics such as enhanced mass transport,precise laminar flow control and the ability to expand production scale progressively.In this comprehensive review,the underlying fundamentals of the paired electrosynthesis are initially summarized,followed by categorizing the paired electrosynthesis including parallel paired electrosynthesis,divergent paired electrosynthesis,convergent paired electrosynthesis,sequential paired electrosynthesis and linear paired electrosynthesis.Thereafter,a holistic overview of microfluidic reactor equipment,integral fundamentals and research methodology as well as channel extension and scale-up strategies is proposed.The established fundamentals and evaluated metrics further inspired the applications of microfluidic reactors in paired electrosynthesis.This work stimulated the overwhelming investigation of mechanism discovery,material screening strategies,and device assemblies.
基金the National Natural Science Foundation of China(22078030)the National Key Research and Development Project(2019YFC1905802,2022YFB3504305)+1 种基金the Joint Funds of the National Natural Science Foundation of China(U1802255,CSTB2022NSCQ-LZX0014)the Key Project of Independent Research Project of State Key Laboratory of Coal Mine Disaster Dynamics and Control(2011DA105287-zd201902).
文摘Leveraging big data signal processing offers a pathway to the development of artificial intelligencedriven equipment.The analysis of fluid flow signals and the characterization of fluid flow behavior are of critical in two-phase flow studies.Significant research efforts have focused on discerning flow regimes using various signal analysis methods.In this review,recent advances in time series signals analysis algorithms for stirred tank reactors have been summarized,and the detailed methodologies are categorized into the frequency domain methods,time-frequency domain methods,and state space methods.The strengths,limitations,and notable findings of each algorithm are highlighted.Additionally,the interrelationships between these methodologies have also been discussed,as well as the present progress achieved in various applications.Future research directions and challenges are also predicted to provide an overview of current research trends in data mining of time series for analyzing flow regimes and chaotic signals.This review offers a comprehensive summary for extracting and characterizing fluid flow behavior and serves as a theoretical reference for optimizing the characterization of chaotic signals in future research endeavors.
基金the National Key Research and Development Program of China (2022YFB3504300)the Graduate Research and Innovation Foundation of Chongqing (CYB240045)+1 种基金the Fundamental Research Funds for the Central Universities(2024CDJXY010)the Large-scale Instrument and Equipment Function Development Program of Chongqing University(gnkf2024019) for supporting this work。
文摘The formation,evolution and modelling of organized flow structures(e.g.,segregated regions and centre-surface vortices) and their destruction in unbaffled stirred tank reactors(UBSTRs) have been a hot research topic in the field of fluid mixing.In this paper,the relevant researches in the past 30 years were reviewed,focusing on the application of asymmetric mixing.In particular,by drawing on chaotic phenomena in nature and human society(e.g.,kneading-dough,traffic flow,frightened school of fish),we propose a fluid mixing mechanism:squeezing-induced chaotic mixing,and further propose a bionics-imitation-simulation design concept for UBSTRs.This concept is also an important inspiration for the design of other chemical reactors.
基金supported by the Industry-University Cooperation Project in Fujian Province University(No.2023H6006)the State Key Laboratory of Reliability and Intelligence of Electrical Equipment(No.EERI-KF20200005)。
文摘Artificial intelligence has potential for forecasting reactor conditions in the nuclear industry.Owing to economic and security concerns,a common method is to train data generated by simulators.However,achieving a satisfactory performance in practical applications is difficult because simulators imperfectly emulate reality.To bridge this gap,we propose a novel framework called simulation-to-reality domain adaptation(SRDA)for forecasting the operating parameters of nuclear reactors.The SRDA model employs a transformer-based feature extractor to capture dynamic characteristics and temporal dependencies.A parameter predictor with an improved logarithmic loss function is specifically designed to adapt to varying reactor powers.To fuse prior reactor knowledge from simulations with reality,the domain discriminator utilizes an adversarial strategy to ensure the learning of deep domain-invariant features,and the multiple kernel maximum mean discrepancy minimizes their discrepancies.Experiments on neutron fluxes and temperatures from a pressurized water reactor illustrate that the SRDA model surpasses various advanced methods in terms of predictive performance.This study is the first to use domain adaptation for real-world reactor prediction and presents a feasible solution for enhancing the transferability and generalizability of simulated data.
文摘Accurate water level measurement in nuclear reactors,particularly in PWRs(pressurized water reactors)and BWRs(boiling water reactors),is essential for ensuring the safety and efficiency of reactor operations.K-type HJTCs(heated junction thermocouples)are widely used for this purpose due to their ability to withstand extreme temperatures and radiation conditions.This article explores the role of HJTCs in reactor water level measurement and compares the performance of 2-wire and 3-wire connections.While the 2-wire connection is simple and cost-effective,it can introduce measurement inaccuracies due to wire resistance.In contrast,the 3-wire connection compensates for lead resistance,offering more precise and reliable measurements,particularly in long-distance applications.This paper discusses the operational considerations of these wiring configurations in the context of nuclear reactors and highlights the importance of choosing the appropriate connection type to optimize safety and measurement accuracy in PWR and BWR reactors.
文摘Knowing the precise relationship between fuel loading and reactivity is essential for guiding reactor criticality extrapolation and online refueling in molten salt reactors(MSRs).This study aims to explore and explain the linear relationship between reactivity and the reciprocal of uranium concentration in thermal-spectrum MSRs.By applying neutron balance theory,we analyzed the neutron absorption cross sections of various nuclides in single-lattice models with varying fuel concentrations.Our findings reveal a simple linear correlation between reactivity and the reciprocal of uranium concentration,which can be explained from the perspective of nuclear reaction cross sections that adhere to the 1/v law in the thermal neutron spectrum.Furthermore,we identified that the neutron absorption single-group cross sections of structural materials and carrier salts exhibit an approximately linear relationship with the fission single-group cross section of ^(235) U;similarly,the reciprocal of ^(235)U’s fission cross section exhibits an approximately linear relationship with uranium concentration.This linear relationship deviates as the volume fraction of molten salt increases,due to a greater proportion of neutrons being captured in the resonance energy spectrum.However,it remains valid for molten salt volume fractions up to 25%and demonstrates broad applicability in the physical design and operation of thermal molten salt reactors.
文摘Subcritical reactors(SCRs)or subcritical assemblies(SCAs)are the main infrastructure for designing power reactors.These reactors are widely used for training and research because of their high level of inherent safety.The objective of this study is to design a subcritical reactor using a pressurized water reactor(PWR)conventional fuel following two safety points.In the first approach,deeply placed SCR cores with an infinite multiplication factor(k_(∞))of less than unity were identified using the DRAGON lattice code.In the second approach,subcritical reactor cores with an effective multiplication factor(k_(eff))of less than unity were determined by coupling the cell calculations of the DRAGON lattice code and core calculations of the DONJON code.For the deeply subcritical reactor design,it was found that the reactor would remain inherently subcritical while using fuel rods with ^(235)U enrichment of up to 0.9%,regardless of the pitch of the fuel rods.In the second approach,the optimal pitches(1.3 to 2.3 cm)were determined for different fuel enrichment values from 1 to 5%.Subsequently,the k_(eff) was obtained for a fuel rod arrangement of 8×8 to 80×80,and the states in which the reactor would be subcritical were determined for different fuel enrichments at the corresponding optimal pitch.To validate the models used in the DRAGON and DONJON codes,the k_(eff) of the Isfahan Light Water Subcritical Reactor(LWSCR)was experimentally measured and compared with the results of the calculations.Finally,the effects of fuel and moderator temperature changes were investigated to ensure that the designed assemblies remained in the subcritical state at all operational temperatures.
基金supported by the National Natural Science Foundation of China (Grant No.12575180)the Lingchuang Research Project of China National Nuclear Corporation (CNNC)。
文摘From an engineering feasibility standpoint, what level of performance metrics can be ultimately achieved when designing a reactor using well-established nuclear fuels and structural materials that have already undergone irradiation testing? The irradiation capability, which hinges on parameters like neutron flux level, irradiation channels' volume, and fuel cycle duration, is a core indicator for high-flux reactors. We propose a conceptual design of an ultra-high flux fast reactor(UFFR) with strong irradiation capability, which utilizes U-20Pu-10Zr alloy fuel and employs lead-bismuth as the coolant. The maximum neutron flux in the core reaches 1.32×10^(16) cm^(-2)s^(-1), while the average neutron flux in the irradiation channels attains 1.19×10^(16) cm^(-2)s^(-1). The volume of the central irradiation channel exceeds 10000 cm^(3), and the fuel cycle duration is 165 d, placing all its performance indicators among the top in the world. Based on the analyses of reactor physics and thermalhydraulics, it has been demonstrated that all reactivity coefficients are negative and all physical parameters meet the design criteria, ensuring the inherent safety of UFFR. An assessment of the irradiation capability has been carried out based on californium-252(^(252)Cf) production, indicating that the irradiation capability of UFFR surpasses that of the high flux isotope reactor(HFIR). The yield of ^(252)Cf from UFFR is 14.39 times that of HFIR, and its nuclei conversion rate is 3.21 times that of HFIR.
基金supported in part by the National Natural Science Foundation of China(No.12305196)Anhui Provincial Natural Science Foundation(No.2308085QA23)+1 种基金Open Fund of Magnetic confinement Fusion Laboratory of Anhui Province(No.2023AMF03003)Science Foundation of Institute of Plasma Physics,Chinese Academy of Sciences(No.DSJJ-2024-10).
文摘A low-temperature-resistant and high-strength stainless-steel jacket is a key component in the superconducting magnet of a fusion reactor.The development of cryogenic structural materials with high strength and toughness poses a challenge for the future development of high-field superconducting magnets in fusion reactors.The yield strength of the International Thermonuclear Experimental Reactor developed for low-temperature structural materials at 4.2K is below 1100MPa,which fails to meet the demand for structural components with yield strengths exceeding 1500MPa at 4.2K in the future fusion reactors.CHSN01(formerly N50H),which is a low-temperature structural material developed in China,exhibits exceptional strength and toughness,thereby making it highly promising for practical applications.Recently,a 30 t jacket measuring approximately 5000m in total length was produced.Its low-temperature mechanical properties were tested using a sampling method to ensure compliance with application requirements.This paper presents the experimental data of the CHSN01 jacket and tests of the physical properties of the material in the temperature range of 4–300 K.The physical properties were unaffected by magnetic field.Furthermore,this paper discusses the feasibility of employing CHSN01 as a cryogenic structural material capable of withstanding high magnetic fields in next-generation fusion reactors.
基金financial support from the Nuclear Energy Science&Technology and Human Resource Development Project of the Japan Atomic Energy Agency/Collaborative Laboratories for Advanced Decommissioning Science(No.R04I034)The author Ruicong Xu appreciates the scholarship(financial support)from the China Scholarship Council(CSC,No.202106380073).
文摘Laser-induced aerosols,predominantly submicron in size,pose significant environmental and health risks during the decommissioning of nuclear reactors.This study experimentally investigated the removal of laser-generated aerosol particles using a water spray system integrated with an innovative system for pre-injecting electrically charged mist in our facility.To simulate aerosol generation in reactor decommissioning,a high-power laser was used to irradiate various materials(including stainless steel,carbon steel,and concrete),generating aerosol particles that were agglomerated with injected water mist and subsequently scavenged by water spray.Experimental results demonstrate enhanced aerosol removal via aerosol-mist agglomeration,with charged mist significantly improving particle capture by increasing wettability and size.The average improvements for the stainless steel,carbon steel,and concrete were 40%,44%,and 21%,respectively.The results of experiments using charged mist with different polarities(both positive and negative)and different surface coatings reveal that the dominant polarity of aerosols varies with the irradiated materials,influenced by their crystal structure and electron emission properties.Notably,surface coatings such as ZrO_(2)and CeO_(2)were found to possibly alter aerosol charging characteristics,thereby affecting aerosol removal efficiency with charged mist configurations.The innovative aerosol-mist agglomeration approach shows promise in mitigating radiation exposure,ensuring environmental safety,and reducing contaminated water during reactor dismantling.This study contributes critical knowledge for the development of advanced aerosol management strategies for nuclear reactor decommissioning.The understanding obtained in this work is also expected to be useful for various environmental and chemical engineering applications such as gas decontamination,air purification,and pollution control.
基金supported by the National Key Projects for Fundamental Research and development of China(2020YFA0710202)the China Postdoctoral Science Foundation(2024M761567)Shandong Postdoctoral Science Foundation(SDCX-ZG-202400271).
文摘The synthesis of propylene carbonate(PC)from CO_(2) and propylene oxide(PO)is a typical gas-liquid biphasic system,where gas-liquid mass transfer efficiency significantly influences CO_(2) cycloaddition reactions.Here,we proposed a microchannel reaction system for the CO_(2) cycloaddition reaction catalyzed by ionic liquid within an aqueous environment.The effect of liquid flow rate,temperature and residence time on gas-liquid flow pattern,catalytic performance and mass transfer were systematically investigated.The results revealed that the PC generation rate reached 560.11 mmol·ml^(−1)·h^(−1)at a 50 cm of flow distance under reaction conditions of 105℃,2.5 MPa,QG=176 ml·min^(−1) and QL=0.3 ml·min^(−1).Variations in mass transfer rate and reaction rate at different flow distances were experimentally studied.The reaction efficiency gradually decreased with increasing flow distance,which were attributed to the reduction of mass transfer caused by decreasing bubble velocity.Optimizing bubble velocity at an appropriate position enhanced reaction efficiency by improving mass transfer,achieving a 97.7%PC yield within 2.85 min.Furthermore,a kinetic model coupling intrinsic kinetics with gas-liquid mass transfer was developed for CO_(2) cycloaddition reaction.The kinetic model was applied to predict PC reaction rates in microchannel reactors at various temperatures and liquid flow rates,achieving an average relative error of 9.6%.
