To generate a neutron beam exhibiting a Maxwellian energy distribution with narrow emission angles for measuring the neutron capture reaction rates of the s-process nuclides,a monoenergetic 3.4 MeV proton beam produce...To generate a neutron beam exhibiting a Maxwellian energy distribution with narrow emission angles for measuring the neutron capture reaction rates of the s-process nuclides,a monoenergetic 3.4 MeV proton beam produced by the tandem-accelerator in the China Institute of Atomic Energy was utilized.The proton beam was first transmitted through a 60.5μm aluminum foil and then impinged on a natural LiF target to produce neutron beam via^(7)Li(p,n)7Be reaction.The quasi-Gaussian energy distribution of protons in the LiF target resulted in neutron energy spectra that agreed with a Maxwellian energy distribution at kT=(22±2)keV,which was achieved by integrating neutrons detected within an emission angle of 65.0°±2.6°using a ^(6)Li glass detector positioned at 65°relative to the proton beam direction.The narrow angular spread of the Maxwelliandistributed neutron beam enables direct measurement of neutron capture cross-sections for most s-process nuclides,overcoming previous experimental limitations associated with broad angular distributions.展开更多
One of the main issues in designing optimum tapered cascades for uranium enrichment for annual fuel production in a power reactor is whether to employ large(fat)or small(thin)cascades.What will be the permissible and ...One of the main issues in designing optimum tapered cascades for uranium enrichment for annual fuel production in a power reactor is whether to employ large(fat)or small(thin)cascades.What will be the permissible and optimal ranges of the number of machines that can be used in a cascade?For the first time,the permissible and optimal ranges of the number of gas centrifuges that can be utilized in a cascade were investigated using two types of centrifuges,and the performance of small and large tapered cascades was discussed.The particle swarm optimization algorithm(PSO)has been used to optimize tapered cascades.The results show:(1)For the first centrifuge,41 cascades(91≤n≤4897)and for the second centrifuge,49 cascades(18≤n≤3839)with small and large sizes can be used in enrichment facilities,and the best cascade for them has 530(with 23 stages)and 39(with 7 stages)centrifuges,respectively.(2)For both centrifuges,when 600≤n(number of centrifuges=n),the large cascade performance changes are relatively insignificant.(3)For both types of gas centrifuges,the annual los s of separation power in enrichment facilities is approximately 1.25%-4.82%of the total separation work required.展开更多
Amidst the growing global emphasis on nuclear safety,the integrity of nuclear reactor systems has garnered attention in the aftermath of consequential events.Moreover,the rapid development of artificial intelligence t...Amidst the growing global emphasis on nuclear safety,the integrity of nuclear reactor systems has garnered attention in the aftermath of consequential events.Moreover,the rapid development of artificial intelligence technology has provided immense opportunities to enhance the safety and economy of nuclear energy.However,data-driven deep learning techniques often lack interpretability,which hinders their applicability in the nuclear energy sector.To address this problem,this study proposes a hybrid data-driven and knowledge-driven artificial intelligence model based on physics-informed neural networks to accurately compute the neutron flux distribution inside a nuclear reactor core.Innovative techniques,such as regional decomposition,intelligent k_(eff)(effective multiplication factor)search,and k_(eff)inversion,have been introduced for the calculation.Furthermore,hyperparameters of the model are automatically optimized using a whale optimization algorithm.A series of computational examples are used to validate the proposed model,demonstrating its applicability,generality,and high accuracy in calculating the neutron flux within the nuclear reactor.The model offers a dependable strategy for computing the neutron flux distribution in nuclear reactors for advanced simulation techniques in the future,including reactor digital twinning.This approach is data-light,requires little to no training data,and still delivers remarkably precise output data.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
Additive manufacturing(AM)is an innovative technique that enables the flexible design and construction of three-dimensional objects.In the nuclear industry,AM enables the use of advanced materials and high-performance...Additive manufacturing(AM)is an innovative technique that enables the flexible design and construction of three-dimensional objects.In the nuclear industry,AM enables the use of advanced materials and high-performance components.Although AM processing has been extensively investigated,the corresponding mechanical properties and structural integrity issues of AM parts have received less attention.This study reviews the mechanical behavior and key challenges of typical AM materials,fuel components,compact heat exchangers with complex geometries,and additive repair of damaged reactor components.The findings of this review will guide the efficient and reliable implementation of AM techniques in nuclear reactors.展开更多
This paper analyzes the role of nuclear power of China's energy structure and industry system. Comparing with other renewable energy the nuclear power chain has very low greenhouse gas emission, so it will play mo...This paper analyzes the role of nuclear power of China's energy structure and industry system. Comparing with other renewable energy the nuclear power chain has very low greenhouse gas emission, so it will play more important role in China's low-carbon economy. The paper also discussed the necessity of nuclear power development to achieve emission reduction, energy structure adjustment, nuclear power safety,environmental protection, enhancement of nuclear power technology, nuclear waste treatment, and disposal, as well as nuclear power plant decommissioning. Based on the safety record and situation of the existing power plants in China, the current status of the development of world nuclear power technology, and the features of the independently designed advanced power plants in China, this paper aims to demonstrate the safety of nuclear power. A nuclear power plant will not cause harm either to the environment and nor to the public according to the real data of radioactivity release, which are obtained from an operational nuclear plant. The development of nuclear power technology can enhance the safety of nuclear power. Further, this paper discusses issues related to the nuclear fuel cycle, the treatment, and disposal strategies of nuclear waste, and the decommissioning of a nuclear power plant, all of which are issues of public concern.展开更多
Introduction-Nuclei near and beyond the proton drip line represent a fascinating frontier in the nuclear landscape. Proton-rich nuclei exhibit intriguing phenomena, such as the Thomas-Ehrman shift and proton-halo stru...Introduction-Nuclei near and beyond the proton drip line represent a fascinating frontier in the nuclear landscape. Proton-rich nuclei exhibit intriguing phenomena, such as the Thomas-Ehrman shift and proton-halo structure. Beyond the proton dripline, nuclei become unbound, allowing protons to be emitted and giving rise to novel radioactive decay modes. Single-proton radioactivity, a process in which some nuclei with an odd number of protons(Z) decay by ejecting a proton, was discovered several decades ago and has been extensively studied [1, 2].展开更多
The Monte Carlo(MC)method offers significant advantages in handling complex geometries and physical processes in particle transport problems and has become a widely used approach in reactor physics analysis,radiation ...The Monte Carlo(MC)method offers significant advantages in handling complex geometries and physical processes in particle transport problems and has become a widely used approach in reactor physics analysis,radiation shielding design,and medical physics.However,with the rapid advancement of new nuclear energy systems,the Monte Carlo method faces challenges in efficiency,accuracy,and adaptability,limiting its effectiveness in meeting modern design requirements.Overcoming technical obstacles related to high-fidelity coupling,high-resolution computation,and intelligent design is essential for using the Monte Carlo method as a reliable tool in numerical analysis for these new nuclear energy systems.To address these challenges,the Nuclear Energy and Application Laboratory(NEAL)team at the University of South China developed a multifunctional and generalized intelligent code platform called MagicMC,based on the Monte Carlo particle transport method.MagicMC is a developing tool dedicated to nuclear applications,incorporating intelligent methodologies.It consists of two primary components:a basic unit and a functional unit.The basic unit,which functions similarly to a standard Monte Carlo particle transport code,includes seven modules:geometry,source,transport,database,tally,output,and auxiliary.The functional unit builds on the basic unit by adding functional modules to address complex and diverse applications in nuclear analysis.MagicMC introduces a dynamic Monte Carlo particle transport algorithm to address time-space particle transport problems within emerging nuclear energy systems and incorporates a CPU-GPU heterogeneous parallel framework to enable high-efficiency,high-resolution simulations for large-scale computational problems.Anticipating future trends in intelligent design,MagicMC integrates several advanced features,including CAD-based geometry modeling,global variance reduction methods,multi-objective shielding optimization,high-resolution activation analysis,multi-physics coupling,and radiation therapy.In this paper,various numerical benchmarks-spanning reactor transient simulations,material activation analysis,radiation shielding optimization,and medical dosimetry analysis-are presented to validate MagicMC.The numerical results demonstrate MagicMC's efficiency,accuracy,and reliability in these preliminary applications,underscoring its potential to support technological advancements in developing high-fidelity,high-resolution,and high-intelligence MC-based tools for advanced nuclear applications.展开更多
Lead(Pb)plays a significant role in the nuclear industry and is extensively used in radiation shielding,radiation protection,neutron moderation,radiation measurements,and various other critical functions.Consequently,...Lead(Pb)plays a significant role in the nuclear industry and is extensively used in radiation shielding,radiation protection,neutron moderation,radiation measurements,and various other critical functions.Consequently,the measurement and evaluation of Pb nuclear data are highly regarded in nuclear scientific research,emphasizing its crucial role in the field.Using the time-of-flight(ToF)method,the neutron leakage spectra from three^(nat)Pb samples were measured at 60°and 120°based on the neutronics integral experimental facility at the China Institute of Atomic Energy(CIAE).The^(nat)Pb sample sizes were30 cm×30 cm×5 cm,30 cm×30 cm×10 cm,and 30 cm×30 cm×15 cm.Neutron sources were generated by the Cockcroft-Walton accelerator,producing approximately 14.5 MeV and 3.5 MeV neutrons through the T(d,n)^(4)He and D(d,n)^(3)He reactions,respectively.Leakage neutron spectra were also calculated by employing the Monte Carlo code of MCNP-4C,and the nuclear data of Pb isotopes from four libraries:CENDL-3.2,JEFF-3.3,JENDL-5,and ENDF/B-Ⅷ.0 were used individually.By comparing the simulation and experimental results,improvements and deficiencies in the evaluated nuclear data of the Pb isotopes were analyzed.Most of the calculated results were consistent with the experimental results;however,a few areas did not fit well.In the(n,el)energy range,the simulated results from CENDL-3.2 were significantly overestimated;in the(n,inl)D and the(n,inl)C energy regions,the results from CENDL-3.2 and ENDF/B-Ⅷ.0 were significantly overestimated at 120°,and the results from JENDL-5 and JEFF-3.3 are underestimated at 60°in the(n,inl)D energy region.The calculated spectra were analyzed by comparing them with the experimental spectra in terms of the neutron spectrum shape and C/E values.The results indicate that the theoretical simulations,using different data libraries,overestimated or underestimated the measured values in certain energy ranges.Secondary neutron energies and angular distributions in the data files have been presented to explain these discrepancies.展开更多
Given the grave local and international network security landscape,a national strategic level analysis indicates that the modernization and advancement within the Industry 4.0 era are closely correlated with overall c...Given the grave local and international network security landscape,a national strategic level analysis indicates that the modernization and advancement within the Industry 4.0 era are closely correlated with overall competitive strength.Consequently,China proposed a strategy for the integration of industrialization and informatization,optimizing and adjusting its industrial structure to swiftly achieve transformation and upgrading in the Industry 4.0 era,thereby enhancing the sophistication of intelligent industrial control systems.The distributed control system in a nuclear power plant functions as an industrial control system,overseeing the operational status of the physical process.Its ability to ensure safe and reliable operation is directly linked to nuclear safety and the cybersecurity of the facility.The management of network security in distributed control systems(DCS)is crucial for achieving this objective.Due to the varying network settings and parameters of the DCS implemented in each nuclear power plant,the network security status of the system sometimes diverges from expectations.During system operation,it will undoubtedly encounter network security issues.Consequently,nuclear power plants utilize the technical criteria outlined in GB/T 22239 to formulate a network security management program aimed at enhancing the operational security of DCS within these facilities.This study utilizes existing network security regulations and standards as a reference to analyze the network security control standards based on the nuclear power plant’s control system.It delineates the fundamental requirements for network security management,facilitating integration with the entire life cycle of the research,development,and application of the nuclear power plant’s distributed control system,thereby establishing a network security management methodology that satisfies the control requirements of the nuclear power plant.Initially,it presents DCS and network security management,outlines current domestic and international network security legislation and standards,and specifies the standards pertinent to the administration of DCS in nuclear power plants.Secondly,the design of network security management for DCS is executed in conjunction with the specific context of nuclear power plants.This encompasses the deployment of network security apparatus,validation of the network security management strategy,and optimization adjustments.Consequently,recommendations beneficial to the network security management of nuclear power plants are compiled,aimed at establishing a management system and incorporating the concept of full life cycle management,which is predicated on system requirements,system design,and both software and hardware considerations.Conversely,it presents the notion of comprehensive life cycle management and suggests network security management strategies encompassing system requirements,system architecture,detailed hardware and software design and implementation,procurement,internal system integration,system validation and acceptance testing,system installation,operational maintenance,system modifications,and decommissioning.We will consistently enhance the performance and functionality of DCS in nuclear power plants,establish a safe and secure operational environment,and thereby facilitate the implementation of DCS in nuclear facilities while ensuring robust network security in the future.展开更多
An accurate and simultaneous ab initio prediction for both light nuclei and nuclear matter has been a longstanding challenge in nuclear physics, due to the significant uncertainties associated with the three-nucleon f...An accurate and simultaneous ab initio prediction for both light nuclei and nuclear matter has been a longstanding challenge in nuclear physics, due to the significant uncertainties associated with the three-nucleon forces.In this Letter, we develop the relativistic quantum Monte Carlo methods for the nuclear ab initio problem, and calculate the ground-state energies of A ≤ 4 nuclei using the two-nucleon Bonn force with an unprecedented high accuracy. The present relativistic results significantly outperform the nonrelativistic results with only twonucleon forces. We demonstrate that both light nuclei and nuclear matter can be well described simultaneously in the relativistic ab initio calculations, even in the absence of three-nucleon forces, and a correlation between the properties of light A ≤ 4 nuclei and the nuclear saturation is revealed. This provides a quantitative understanding of the connection between the light nuclei and nuclear matter saturation properties.展开更多
A floating nuclear power plant(FNPP)is an offshore facility that integrates proven light-water reactor technologies with floating platform characteristics.However,frequent contact with marine environments may lead to ...A floating nuclear power plant(FNPP)is an offshore facility that integrates proven light-water reactor technologies with floating platform characteristics.However,frequent contact with marine environments may lead to wave-induced vibrations and oscillations.This study aimed to evaluate the wave danger on FNPPs,which can negatively impact FNPP functionality.We developed a hydrodynamic model of an FNPP using potential flow theory and computed the frequency-domain fluid dynamic responses.After verifying the hydrodynamic model,we developed a predictive model for FNPP responses.This model utilizes a genetic aggregation methodology for batch prediction while ensuring accuracy.We analyzed all the wave data from a selected sea area over the past 50 years using the constructed surrogate model,enabling us to identify dangerous marine areas.By utilizing the extreme value distribution of important wave heights in these areas,we determined the wave return period,which poses a threat to FNPPs.This provides an important method for analyzing wave hazards to FNPPs.展开更多
The illicit trafficking of special nuclear materials(SNMs)poses a grave threat to global security and necessitates the development of effective nuclear material identification methods.This study investigated a method ...The illicit trafficking of special nuclear materials(SNMs)poses a grave threat to global security and necessitates the development of effective nuclear material identification methods.This study investigated a method to isotopically identify the SNMs,including^(233,235,238)U,^(239-242)Pu,and^(232)Th,based on the detection of delayedγ-rays from photofission fragments.The delayedγ-ray spectra resulting from the photofission of SNMs irradiated by a 14 MeVγbeam with a total of 10~9 were simulated using Geant4.Three high-yield fission fragments,namely^(138)Cs,^(89)Rb,and^(94)Y,were selected as candidate fragments for SNM identification.The yield ratios of these three fragments were calculated,and the results from the different SNMs were compared.The yield ratio of^(138)Cs/^(89)Rb was used to identify most SNMs,including^(233,235,238)U,^(242)Pu,and^(232)Th,with a confidence level above 95%.To identify^(239-241)Pu with the same confidence,a higher total number of 10^(11)γbeams is required.However,although the^(94)Y/^(89)Rb ratio is suitable for elementally identifying SNMs,isotopic identification is difficult.In addition,the count rate of the delayedγabove 3 MeV can be used to rapidly detect the presence of nuclear materials.展开更多
Current sway test platforms for marine nuclear equipment face challenges in meeting the GJB 150.23A requirements.This is primarily because of the performance limitations of conventional actuators under extreme marine ...Current sway test platforms for marine nuclear equipment face challenges in meeting the GJB 150.23A requirements.This is primarily because of the performance limitations of conventional actuators under extreme marine conditions.This study aimed to overcome these constraints using an innovative parallel mechanism design.We developed a novel 6-PUS parallel platform featuring six kinematic chains with hybrid series-parallel actuators.Each chain combines(1)force-speed adaptive transmission,(2)redundant motor-driven dual-screw actuation,and(3)passive load-balancing mechanisms.Comprehensive kinematic/dynamic modeling and experimental validation were conducted.Tests demonstrated the capability of the platform to achieve cyclic speeds of±45°/7 s and±30°/3 s while supporting 10-ton loads.Successful sway tests on nuclear components(reactor pressurizer and control rod drive mechanism)confirmed the operational reliability.This work presented three key innovations:(1)a new parallel-platform architecture that overcomes the limitations of conventional actuators;(2)integrated hybrid actuation with adaptive transmission;and(3)high-speed,heavy-load performance that meets stringent marine testing standards.This solution significantly advances nuclear equipment qualification testing technology.展开更多
Compared to other energy sources,nuclear reactors offer several advantages as a spacecraft power source,including compact size,high power density,and long operating life.These qualities make nuclear power an ideal ene...Compared to other energy sources,nuclear reactors offer several advantages as a spacecraft power source,including compact size,high power density,and long operating life.These qualities make nuclear power an ideal energy source for future deep space exploration.A whole system model of the space nuclear reactor consisting of the reactor neutron kinetics,reactivity control,reactor heat transfer,heat exchanger,and thermoelectric converter was developed.In addition,an electrical power control system was designed based on the developed dynamic model.The GRS method was used to quantitatively calculate the uncertainty of coupling parameters of the neutronics,thermal-hydraulics,and control system for the space reactor.The Spearman correlation coefficient was applied in the sensitivity analysis of system input parameters to output parameters.The calculation results showed that the uncertainty of the output parameters caused by coupling parameters had the most considerable variation,with a relative standard deviation<2.01%.Effective delayed neutron fraction was most sensitive to electrical power.To obtain optimal control performance,the non-dominated sorting genetic algorithm method was employed to optimize the controller parameters based on the uncertainty quantification calculation.Two typical transient simulations were conducted to test the adaptive ability of the optimized controller in the uncertainty dynamic system,including 100%full power(FP)to 90%FP step load reduction transient and 5%FP/min linear variable load transient.The results showed that,considering the influence of system uncertainty,the optimized controller could improve the response speed and load following accuracy of electrical power control,in which the effectiveness and superiority have been verified.展开更多
As a cluster overlap amplitude,the reduced-width amplitude is an important physical quantity for analyzing clustering in the nucleus depending on specified channels and has been calculated and widely applied in nuclea...As a cluster overlap amplitude,the reduced-width amplitude is an important physical quantity for analyzing clustering in the nucleus depending on specified channels and has been calculated and widely applied in nuclear cluster physics.In this review,we briefly revisit the theoretical framework for calculating the reduced-width amplitude,as well as the outlines of cluster models to obtain microscopic or semi-microscopic cluster wave functions.We also introduce the recent progress related to cluster overlap amplitudes,including the implementation of cross-section estimation and extension to three-body clustering analysis.Comprehensive examples are provided to demonstrate the application of the reduced-width amplitude in analyzing clustering structures.展开更多
The heat transfer coefficient of the water surface is an important parameter in the design of thermal discharge in nuclear power plant engineering.In this study,in situ observations were performed in the northwestern ...The heat transfer coefficient of the water surface is an important parameter in the design of thermal discharge in nuclear power plant engineering.In this study,in situ observations were performed in the northwestern South China Sea near a coastal nuclear power plant to evaluate the applicability of heat transfer coefficient calculation algorithms commonly used in marine thermal discharge engineering in China.The results show that the Regulation for Hydraulic and Thermal Model in Cooling Water Projects(SL 160-2012)is not applicable in calculating the heat transfer coefficient in offshore areas.SL 160-2012 significantly overestimates the heat loss at the sea surface.However,Code for Design of Cooling for Industrial Recirculating Water(GB/T 50102-2014)performs well,and its estimation coefficient is roughly consistent with the estimations of the COARE 3.6 bulk algorithm,which is extensively used in physical oceanography for calculating air-sea heat fluxes,and the Gunneberg formula.In a 3-day observation,the average heat transfer coefficients estimated using these three algorithms were 50.4,48.5,and 48.8 W m^(-2)℃^(-1),respectively,with a deviation of less than 4% among them,whereas that estimated using SL 160-2012 was as high as 176.3 W m^(-2)℃^(-1).The abnormally large value of SL 160-2012 is due to its additional cooling term,which is artificially increased by 100 times because of the incorrect unit conversion used when developing the regulation.If this error is corrected,the value will decrease to 50.5 W m^(-2)℃^(-1),which is very close to the estimation of GB/T 50102-2014.展开更多
The integration of additive manufacturing(AM)and topology optimization(TO)has revolutionized the design and production of advanced equipment,providing innovative approaches to solving complex engineering challenges.In...The integration of additive manufacturing(AM)and topology optimization(TO)has revolutionized the design and production of advanced equipment,providing innovative approaches to solving complex engineering challenges.In the nuclear energy sector,achieving an optimal balance between the thermal and hydraulic performance of prismatic fuel elements has long been a key challenge.This study utilizes a coupled fluid-thermal TO method to design fuel elements with one,three,five,and seven inlets/outlets configurations suitable for AM.We systematically examine the impact of varying the number of inlets/outlets on the thermal-hydraulic performance of the elements.The results show that increasing the number of inlets/outlets can enhance the thermal performance of the fuel elements while sacrificing the hydraulic performance.Compared with the conventional design,the 5 inlets/outlets configuration achieved a coordinated improvement in both thermal and hydraulic performance,with a 2.38%enhancement in thermal performance and a 4.38%improvement in hydraulic performance.These findings highlight the significant potential of TO in improving the performance of fuel elements and strongly demonstrate the advantages of the collaborative application of AM and TO.展开更多
In nuclear power engineering,the quality requirements for concrete are extremely stringent.Concrete structures must exhibit high durability to withstand the effects of nuclear radiation,chemical corrosion,and environm...In nuclear power engineering,the quality requirements for concrete are extremely stringent.Concrete structures must exhibit high durability to withstand the effects of nuclear radiation,chemical corrosion,and environmental changes.In particular,nuclear power projects impose higher design standards and safety requirements regarding concrete density.Traditional manual vibration and visual inspection methods are difficult to ensure the required level of concrete compaction.This paper presents an intelligent vibration technology for concrete in nuclear power engineering to enhance construction quality and efficiency.By integrating intelligent sensors,control systems,and data processing algorithms,the technology enables real-time monitoring and evaluation of the vibration process.Results show that intelligent vibration technology effectively ensures the density and uniformity of concrete in nuclear power engineering,thereby improving structural safety and reliability.展开更多
Achieving long spin coherence times is crucial for quantum precision measurements,and closed-loop control techniques are often employed to accomplish this goal.Here,we demonstrate the impact of closed-loop feedback co...Achieving long spin coherence times is crucial for quantum precision measurements,and closed-loop control techniques are often employed to accomplish this goal.Here,we demonstrate the impact of closed-loop feedback control on nuclear spin precession in a metastability exchange optical pumping(MEOP)-based polarized^(3)He system.We analyze the effects of feedback theoretically and validate our predictions experimentally.With optimized feedback parameters,the spin coherence time T_(2)is extended by an order of magnitude.When the feedback strength surpasses a critical threshold,robust maser oscillations are spontaneously excited,demonstrating remarkable resistance to environmental noise and maintaining stable oscillation.This proof-of-principle experiment highlights the viability of MEOP-based^(3)He spin oscillators,especially in low-frequency domains.The operational simplicity and easy integration associated with MEOP-based systems make them particularly promising for fast,high-precision magnetic field measurements.展开更多
基金National Natural Science Foundation of China(12125509,11961141003,12275361,U2267205,12175152,12175121)National Key Research and Development Project(2022YFA1602301)Continuous-support Basic Scientific Research Project。
文摘To generate a neutron beam exhibiting a Maxwellian energy distribution with narrow emission angles for measuring the neutron capture reaction rates of the s-process nuclides,a monoenergetic 3.4 MeV proton beam produced by the tandem-accelerator in the China Institute of Atomic Energy was utilized.The proton beam was first transmitted through a 60.5μm aluminum foil and then impinged on a natural LiF target to produce neutron beam via^(7)Li(p,n)7Be reaction.The quasi-Gaussian energy distribution of protons in the LiF target resulted in neutron energy spectra that agreed with a Maxwellian energy distribution at kT=(22±2)keV,which was achieved by integrating neutrons detected within an emission angle of 65.0°±2.6°using a ^(6)Li glass detector positioned at 65°relative to the proton beam direction.The narrow angular spread of the Maxwelliandistributed neutron beam enables direct measurement of neutron capture cross-sections for most s-process nuclides,overcoming previous experimental limitations associated with broad angular distributions.
文摘One of the main issues in designing optimum tapered cascades for uranium enrichment for annual fuel production in a power reactor is whether to employ large(fat)or small(thin)cascades.What will be the permissible and optimal ranges of the number of machines that can be used in a cascade?For the first time,the permissible and optimal ranges of the number of gas centrifuges that can be utilized in a cascade were investigated using two types of centrifuges,and the performance of small and large tapered cascades was discussed.The particle swarm optimization algorithm(PSO)has been used to optimize tapered cascades.The results show:(1)For the first centrifuge,41 cascades(91≤n≤4897)and for the second centrifuge,49 cascades(18≤n≤3839)with small and large sizes can be used in enrichment facilities,and the best cascade for them has 530(with 23 stages)and 39(with 7 stages)centrifuges,respectively.(2)For both centrifuges,when 600≤n(number of centrifuges=n),the large cascade performance changes are relatively insignificant.(3)For both types of gas centrifuges,the annual los s of separation power in enrichment facilities is approximately 1.25%-4.82%of the total separation work required.
文摘Amidst the growing global emphasis on nuclear safety,the integrity of nuclear reactor systems has garnered attention in the aftermath of consequential events.Moreover,the rapid development of artificial intelligence technology has provided immense opportunities to enhance the safety and economy of nuclear energy.However,data-driven deep learning techniques often lack interpretability,which hinders their applicability in the nuclear energy sector.To address this problem,this study proposes a hybrid data-driven and knowledge-driven artificial intelligence model based on physics-informed neural networks to accurately compute the neutron flux distribution inside a nuclear reactor core.Innovative techniques,such as regional decomposition,intelligent k_(eff)(effective multiplication factor)search,and k_(eff)inversion,have been introduced for the calculation.Furthermore,hyperparameters of the model are automatically optimized using a whale optimization algorithm.A series of computational examples are used to validate the proposed model,demonstrating its applicability,generality,and high accuracy in calculating the neutron flux within the nuclear reactor.The model offers a dependable strategy for computing the neutron flux distribution in nuclear reactors for advanced simulation techniques in the future,including reactor digital twinning.This approach is data-light,requires little to no training data,and still delivers remarkably precise output data.
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 Stable Support Initiative of the State Key Laboratory of Advanced Nuclear Energy Technology(Grant No.YNSW-0124-0101-03)the author Cheng Zhang would like to thank the support by Stable Support Program for Scientific Research of China(Grant No.WDZC-2023-02-02-05).
文摘Additive manufacturing(AM)is an innovative technique that enables the flexible design and construction of three-dimensional objects.In the nuclear industry,AM enables the use of advanced materials and high-performance components.Although AM processing has been extensively investigated,the corresponding mechanical properties and structural integrity issues of AM parts have received less attention.This study reviews the mechanical behavior and key challenges of typical AM materials,fuel components,compact heat exchangers with complex geometries,and additive repair of damaged reactor components.The findings of this review will guide the efficient and reliable implementation of AM techniques in nuclear reactors.
文摘This paper analyzes the role of nuclear power of China's energy structure and industry system. Comparing with other renewable energy the nuclear power chain has very low greenhouse gas emission, so it will play more important role in China's low-carbon economy. The paper also discussed the necessity of nuclear power development to achieve emission reduction, energy structure adjustment, nuclear power safety,environmental protection, enhancement of nuclear power technology, nuclear waste treatment, and disposal, as well as nuclear power plant decommissioning. Based on the safety record and situation of the existing power plants in China, the current status of the development of world nuclear power technology, and the features of the independently designed advanced power plants in China, this paper aims to demonstrate the safety of nuclear power. A nuclear power plant will not cause harm either to the environment and nor to the public according to the real data of radioactivity release, which are obtained from an operational nuclear plant. The development of nuclear power technology can enhance the safety of nuclear power. Further, this paper discusses issues related to the nuclear fuel cycle, the treatment, and disposal strategies of nuclear waste, and the decommissioning of a nuclear power plant, all of which are issues of public concern.
文摘Introduction-Nuclei near and beyond the proton drip line represent a fascinating frontier in the nuclear landscape. Proton-rich nuclei exhibit intriguing phenomena, such as the Thomas-Ehrman shift and proton-halo structure. Beyond the proton dripline, nuclei become unbound, allowing protons to be emitted and giving rise to novel radioactive decay modes. Single-proton radioactivity, a process in which some nuclei with an odd number of protons(Z) decay by ejecting a proton, was discovered several decades ago and has been extensively studied [1, 2].
基金supported by the National Natural Science Foundation of China(Nos.12475174 and U2267207)YueLuShan Center Industrial Innovation(No.2024YCII0108)+2 种基金Natural Science Foundation of Hunan Province(No.2022JJ40345)Science and Technology Innovation Project of Hengyang(No.202250045336)the Project of State Key Laboratory of Radiation Medicine and Protection,Soochow University(No.GZK12023031)。
文摘The Monte Carlo(MC)method offers significant advantages in handling complex geometries and physical processes in particle transport problems and has become a widely used approach in reactor physics analysis,radiation shielding design,and medical physics.However,with the rapid advancement of new nuclear energy systems,the Monte Carlo method faces challenges in efficiency,accuracy,and adaptability,limiting its effectiveness in meeting modern design requirements.Overcoming technical obstacles related to high-fidelity coupling,high-resolution computation,and intelligent design is essential for using the Monte Carlo method as a reliable tool in numerical analysis for these new nuclear energy systems.To address these challenges,the Nuclear Energy and Application Laboratory(NEAL)team at the University of South China developed a multifunctional and generalized intelligent code platform called MagicMC,based on the Monte Carlo particle transport method.MagicMC is a developing tool dedicated to nuclear applications,incorporating intelligent methodologies.It consists of two primary components:a basic unit and a functional unit.The basic unit,which functions similarly to a standard Monte Carlo particle transport code,includes seven modules:geometry,source,transport,database,tally,output,and auxiliary.The functional unit builds on the basic unit by adding functional modules to address complex and diverse applications in nuclear analysis.MagicMC introduces a dynamic Monte Carlo particle transport algorithm to address time-space particle transport problems within emerging nuclear energy systems and incorporates a CPU-GPU heterogeneous parallel framework to enable high-efficiency,high-resolution simulations for large-scale computational problems.Anticipating future trends in intelligent design,MagicMC integrates several advanced features,including CAD-based geometry modeling,global variance reduction methods,multi-objective shielding optimization,high-resolution activation analysis,multi-physics coupling,and radiation therapy.In this paper,various numerical benchmarks-spanning reactor transient simulations,material activation analysis,radiation shielding optimization,and medical dosimetry analysis-are presented to validate MagicMC.The numerical results demonstrate MagicMC's efficiency,accuracy,and reliability in these preliminary applications,underscoring its potential to support technological advancements in developing high-fidelity,high-resolution,and high-intelligence MC-based tools for advanced nuclear applications.
基金supported by the National Natural Science Foundation of China(Nos.11775311 and U2067205)the Stable Support Basic Research Program Grant(BJ010261223282)the Research and Development Project of China National Nuclear Corporation。
文摘Lead(Pb)plays a significant role in the nuclear industry and is extensively used in radiation shielding,radiation protection,neutron moderation,radiation measurements,and various other critical functions.Consequently,the measurement and evaluation of Pb nuclear data are highly regarded in nuclear scientific research,emphasizing its crucial role in the field.Using the time-of-flight(ToF)method,the neutron leakage spectra from three^(nat)Pb samples were measured at 60°and 120°based on the neutronics integral experimental facility at the China Institute of Atomic Energy(CIAE).The^(nat)Pb sample sizes were30 cm×30 cm×5 cm,30 cm×30 cm×10 cm,and 30 cm×30 cm×15 cm.Neutron sources were generated by the Cockcroft-Walton accelerator,producing approximately 14.5 MeV and 3.5 MeV neutrons through the T(d,n)^(4)He and D(d,n)^(3)He reactions,respectively.Leakage neutron spectra were also calculated by employing the Monte Carlo code of MCNP-4C,and the nuclear data of Pb isotopes from four libraries:CENDL-3.2,JEFF-3.3,JENDL-5,and ENDF/B-Ⅷ.0 were used individually.By comparing the simulation and experimental results,improvements and deficiencies in the evaluated nuclear data of the Pb isotopes were analyzed.Most of the calculated results were consistent with the experimental results;however,a few areas did not fit well.In the(n,el)energy range,the simulated results from CENDL-3.2 were significantly overestimated;in the(n,inl)D and the(n,inl)C energy regions,the results from CENDL-3.2 and ENDF/B-Ⅷ.0 were significantly overestimated at 120°,and the results from JENDL-5 and JEFF-3.3 are underestimated at 60°in the(n,inl)D energy region.The calculated spectra were analyzed by comparing them with the experimental spectra in terms of the neutron spectrum shape and C/E values.The results indicate that the theoretical simulations,using different data libraries,overestimated or underestimated the measured values in certain energy ranges.Secondary neutron energies and angular distributions in the data files have been presented to explain these discrepancies.
文摘Given the grave local and international network security landscape,a national strategic level analysis indicates that the modernization and advancement within the Industry 4.0 era are closely correlated with overall competitive strength.Consequently,China proposed a strategy for the integration of industrialization and informatization,optimizing and adjusting its industrial structure to swiftly achieve transformation and upgrading in the Industry 4.0 era,thereby enhancing the sophistication of intelligent industrial control systems.The distributed control system in a nuclear power plant functions as an industrial control system,overseeing the operational status of the physical process.Its ability to ensure safe and reliable operation is directly linked to nuclear safety and the cybersecurity of the facility.The management of network security in distributed control systems(DCS)is crucial for achieving this objective.Due to the varying network settings and parameters of the DCS implemented in each nuclear power plant,the network security status of the system sometimes diverges from expectations.During system operation,it will undoubtedly encounter network security issues.Consequently,nuclear power plants utilize the technical criteria outlined in GB/T 22239 to formulate a network security management program aimed at enhancing the operational security of DCS within these facilities.This study utilizes existing network security regulations and standards as a reference to analyze the network security control standards based on the nuclear power plant’s control system.It delineates the fundamental requirements for network security management,facilitating integration with the entire life cycle of the research,development,and application of the nuclear power plant’s distributed control system,thereby establishing a network security management methodology that satisfies the control requirements of the nuclear power plant.Initially,it presents DCS and network security management,outlines current domestic and international network security legislation and standards,and specifies the standards pertinent to the administration of DCS in nuclear power plants.Secondly,the design of network security management for DCS is executed in conjunction with the specific context of nuclear power plants.This encompasses the deployment of network security apparatus,validation of the network security management strategy,and optimization adjustments.Consequently,recommendations beneficial to the network security management of nuclear power plants are compiled,aimed at establishing a management system and incorporating the concept of full life cycle management,which is predicated on system requirements,system design,and both software and hardware considerations.Conversely,it presents the notion of comprehensive life cycle management and suggests network security management strategies encompassing system requirements,system architecture,detailed hardware and software design and implementation,procurement,internal system integration,system validation and acceptance testing,system installation,operational maintenance,system modifications,and decommissioning.We will consistently enhance the performance and functionality of DCS in nuclear power plants,establish a safe and secure operational environment,and thereby facilitate the implementation of DCS in nuclear facilities while ensuring robust network security in the future.
基金supported in part by the National Natural Science Foundation of China (Grant Nos. 12141501, 123B2080, 12435006, 12475117, and 11935003)the National Key Laboratory of Neutron Science and Technology (Grant No. NST202401016)+2 种基金the National Key R&D Program of China (Grant No. 2024YFE0109803)the High-performance Computing Platform of Peking Universitythe funding support from the State Key Laboratory of Nuclear Physics and Technology, Peking University (Grant No. NPT2023ZX03)。
文摘An accurate and simultaneous ab initio prediction for both light nuclei and nuclear matter has been a longstanding challenge in nuclear physics, due to the significant uncertainties associated with the three-nucleon forces.In this Letter, we develop the relativistic quantum Monte Carlo methods for the nuclear ab initio problem, and calculate the ground-state energies of A ≤ 4 nuclei using the two-nucleon Bonn force with an unprecedented high accuracy. The present relativistic results significantly outperform the nonrelativistic results with only twonucleon forces. We demonstrate that both light nuclei and nuclear matter can be well described simultaneously in the relativistic ab initio calculations, even in the absence of three-nucleon forces, and a correlation between the properties of light A ≤ 4 nuclei and the nuclear saturation is revealed. This provides a quantitative understanding of the connection between the light nuclei and nuclear matter saturation properties.
文摘A floating nuclear power plant(FNPP)is an offshore facility that integrates proven light-water reactor technologies with floating platform characteristics.However,frequent contact with marine environments may lead to wave-induced vibrations and oscillations.This study aimed to evaluate the wave danger on FNPPs,which can negatively impact FNPP functionality.We developed a hydrodynamic model of an FNPP using potential flow theory and computed the frequency-domain fluid dynamic responses.After verifying the hydrodynamic model,we developed a predictive model for FNPP responses.This model utilizes a genetic aggregation methodology for batch prediction while ensuring accuracy.We analyzed all the wave data from a selected sea area over the past 50 years using the constructed surrogate model,enabling us to identify dangerous marine areas.By utilizing the extreme value distribution of important wave heights in these areas,we determined the wave return period,which poses a threat to FNPPs.This provides an important method for analyzing wave hazards to FNPPs.
基金supported by the National Key Research and Development Program(No.2022YFA1603300)the National Natural Science Foundation of China(Nos.U2230133,12305266,11921006,12405282)National Grand Instrument Project(No.2019YFF01014400)。
文摘The illicit trafficking of special nuclear materials(SNMs)poses a grave threat to global security and necessitates the development of effective nuclear material identification methods.This study investigated a method to isotopically identify the SNMs,including^(233,235,238)U,^(239-242)Pu,and^(232)Th,based on the detection of delayedγ-rays from photofission fragments.The delayedγ-ray spectra resulting from the photofission of SNMs irradiated by a 14 MeVγbeam with a total of 10~9 were simulated using Geant4.Three high-yield fission fragments,namely^(138)Cs,^(89)Rb,and^(94)Y,were selected as candidate fragments for SNM identification.The yield ratios of these three fragments were calculated,and the results from the different SNMs were compared.The yield ratio of^(138)Cs/^(89)Rb was used to identify most SNMs,including^(233,235,238)U,^(242)Pu,and^(232)Th,with a confidence level above 95%.To identify^(239-241)Pu with the same confidence,a higher total number of 10^(11)γbeams is required.However,although the^(94)Y/^(89)Rb ratio is suitable for elementally identifying SNMs,isotopic identification is difficult.In addition,the count rate of the delayedγabove 3 MeV can be used to rapidly detect the presence of nuclear materials.
基金Supported by Shanghai Nuclear Engineering Research&Design Institute Co.,Ltd.
文摘Current sway test platforms for marine nuclear equipment face challenges in meeting the GJB 150.23A requirements.This is primarily because of the performance limitations of conventional actuators under extreme marine conditions.This study aimed to overcome these constraints using an innovative parallel mechanism design.We developed a novel 6-PUS parallel platform featuring six kinematic chains with hybrid series-parallel actuators.Each chain combines(1)force-speed adaptive transmission,(2)redundant motor-driven dual-screw actuation,and(3)passive load-balancing mechanisms.Comprehensive kinematic/dynamic modeling and experimental validation were conducted.Tests demonstrated the capability of the platform to achieve cyclic speeds of±45°/7 s and±30°/3 s while supporting 10-ton loads.Successful sway tests on nuclear components(reactor pressurizer and control rod drive mechanism)confirmed the operational reliability.This work presented three key innovations:(1)a new parallel-platform architecture that overcomes the limitations of conventional actuators;(2)integrated hybrid actuation with adaptive transmission;and(3)high-speed,heavy-load performance that meets stringent marine testing standards.This solution significantly advances nuclear equipment qualification testing technology.
基金supported by the National Natural Science Foundation of China(12305185)Natural Science Foundation of Hunan Province,China(No.2023JJ50122)+1 种基金International Cooperative Research Project of the Ministry of Education,China(No.HZKY20220355)Scientific Research Foundation of the Education Department of Hunan Province,China(No.22A0307).
文摘Compared to other energy sources,nuclear reactors offer several advantages as a spacecraft power source,including compact size,high power density,and long operating life.These qualities make nuclear power an ideal energy source for future deep space exploration.A whole system model of the space nuclear reactor consisting of the reactor neutron kinetics,reactivity control,reactor heat transfer,heat exchanger,and thermoelectric converter was developed.In addition,an electrical power control system was designed based on the developed dynamic model.The GRS method was used to quantitatively calculate the uncertainty of coupling parameters of the neutronics,thermal-hydraulics,and control system for the space reactor.The Spearman correlation coefficient was applied in the sensitivity analysis of system input parameters to output parameters.The calculation results showed that the uncertainty of the output parameters caused by coupling parameters had the most considerable variation,with a relative standard deviation<2.01%.Effective delayed neutron fraction was most sensitive to electrical power.To obtain optimal control performance,the non-dominated sorting genetic algorithm method was employed to optimize the controller parameters based on the uncertainty quantification calculation.Two typical transient simulations were conducted to test the adaptive ability of the optimized controller in the uncertainty dynamic system,including 100%full power(FP)to 90%FP step load reduction transient and 5%FP/min linear variable load transient.The results showed that,considering the influence of system uncertainty,the optimized controller could improve the response speed and load following accuracy of electrical power control,in which the effectiveness and superiority have been verified.
基金supported by the National Key R&D Program of China(No.2023YFA1606701)the National Natural Science Foundation of China(Nos.12175042 and 12147101)。
文摘As a cluster overlap amplitude,the reduced-width amplitude is an important physical quantity for analyzing clustering in the nucleus depending on specified channels and has been calculated and widely applied in nuclear cluster physics.In this review,we briefly revisit the theoretical framework for calculating the reduced-width amplitude,as well as the outlines of cluster models to obtain microscopic or semi-microscopic cluster wave functions.We also introduce the recent progress related to cluster overlap amplitudes,including the implementation of cross-section estimation and extension to three-body clustering analysis.Comprehensive examples are provided to demonstrate the application of the reduced-width amplitude in analyzing clustering structures.
基金supported by the Laoshan Laboratory(No.LSKJ202201600)the National Natural Science Foundation of China(No.41821004)。
文摘The heat transfer coefficient of the water surface is an important parameter in the design of thermal discharge in nuclear power plant engineering.In this study,in situ observations were performed in the northwestern South China Sea near a coastal nuclear power plant to evaluate the applicability of heat transfer coefficient calculation algorithms commonly used in marine thermal discharge engineering in China.The results show that the Regulation for Hydraulic and Thermal Model in Cooling Water Projects(SL 160-2012)is not applicable in calculating the heat transfer coefficient in offshore areas.SL 160-2012 significantly overestimates the heat loss at the sea surface.However,Code for Design of Cooling for Industrial Recirculating Water(GB/T 50102-2014)performs well,and its estimation coefficient is roughly consistent with the estimations of the COARE 3.6 bulk algorithm,which is extensively used in physical oceanography for calculating air-sea heat fluxes,and the Gunneberg formula.In a 3-day observation,the average heat transfer coefficients estimated using these three algorithms were 50.4,48.5,and 48.8 W m^(-2)℃^(-1),respectively,with a deviation of less than 4% among them,whereas that estimated using SL 160-2012 was as high as 176.3 W m^(-2)℃^(-1).The abnormally large value of SL 160-2012 is due to its additional cooling term,which is artificially increased by 100 times because of the incorrect unit conversion used when developing the regulation.If this error is corrected,the value will decrease to 50.5 W m^(-2)℃^(-1),which is very close to the estimation of GB/T 50102-2014.
基金supported by National Natural Science Foundation of China(Grant No.1257021702)National Key Research and Development Program of China(Grant No.2022YFB4603101).
文摘The integration of additive manufacturing(AM)and topology optimization(TO)has revolutionized the design and production of advanced equipment,providing innovative approaches to solving complex engineering challenges.In the nuclear energy sector,achieving an optimal balance between the thermal and hydraulic performance of prismatic fuel elements has long been a key challenge.This study utilizes a coupled fluid-thermal TO method to design fuel elements with one,three,five,and seven inlets/outlets configurations suitable for AM.We systematically examine the impact of varying the number of inlets/outlets on the thermal-hydraulic performance of the elements.The results show that increasing the number of inlets/outlets can enhance the thermal performance of the fuel elements while sacrificing the hydraulic performance.Compared with the conventional design,the 5 inlets/outlets configuration achieved a coordinated improvement in both thermal and hydraulic performance,with a 2.38%enhancement in thermal performance and a 4.38%improvement in hydraulic performance.These findings highlight the significant potential of TO in improving the performance of fuel elements and strongly demonstrate the advantages of the collaborative application of AM and TO.
基金The Advanced Civil Design and Construction Technology Joint LAB of Nuclear Engineering(Project No.:KY23015).
文摘In nuclear power engineering,the quality requirements for concrete are extremely stringent.Concrete structures must exhibit high durability to withstand the effects of nuclear radiation,chemical corrosion,and environmental changes.In particular,nuclear power projects impose higher design standards and safety requirements regarding concrete density.Traditional manual vibration and visual inspection methods are difficult to ensure the required level of concrete compaction.This paper presents an intelligent vibration technology for concrete in nuclear power engineering to enhance construction quality and efficiency.By integrating intelligent sensors,control systems,and data processing algorithms,the technology enables real-time monitoring and evaluation of the vibration process.Results show that intelligent vibration technology effectively ensures the density and uniformity of concrete in nuclear power engineering,thereby improving structural safety and reliability.
基金supported by the National Natural Science Foundation of China(Grant No.U2230207)。
文摘Achieving long spin coherence times is crucial for quantum precision measurements,and closed-loop control techniques are often employed to accomplish this goal.Here,we demonstrate the impact of closed-loop feedback control on nuclear spin precession in a metastability exchange optical pumping(MEOP)-based polarized^(3)He system.We analyze the effects of feedback theoretically and validate our predictions experimentally.With optimized feedback parameters,the spin coherence time T_(2)is extended by an order of magnitude.When the feedback strength surpasses a critical threshold,robust maser oscillations are spontaneously excited,demonstrating remarkable resistance to environmental noise and maintaining stable oscillation.This proof-of-principle experiment highlights the viability of MEOP-based^(3)He spin oscillators,especially in low-frequency domains.The operational simplicity and easy integration associated with MEOP-based systems make them particularly promising for fast,high-precision magnetic field measurements.
