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nuclear Science and Techniques 2024年第1期35卷 145-154页

作者： M.Hajipour G.R.Ansarifar Department of Nuclear Engineering Faculty of PhysicsUniversity of IsfahanIsfahan 81746-73441Iran

nuclear power plants exhibit non-linear and time-variable dynamics.Therefore,designing a control system that sets the reactor power and forces it to follow the desired load is complicated.A supercritical water reactor(SCWR)is a fourth-generation conceptual reactor.In an SCWR,the non-linear dynamics of the reactor require a controller capable of control-ling the nonlinearities.In this study,a pressure-tube-type SCWR was controlled during reactor power maneuvering with a higher order sliding mode,and the reactor outgoing steam temperature and pressure were controlled simultaneously.In an SCWR,the temperature,pressure,and power must be maintained at a setpoint(desired value)during power maneuvering.Reactor point kinetics equations with three groups of delayed neutrons were used in the simulation.Higher-order and classic sliding mode controllers were separately manufactured to control the plant and were compared with the PI controllers speci-fied in previous studies.The controlled parameters were reactor power,steam temperature,and pressure.Notably,for these parameters,the PI controller had certain instabilities in the presence of disturbances.The classic sliding mode controller had a higher accuracy and stability;however its main drawback was the chattering phenomenon.HOSMC was highly accurate and stable and had a small computational cost.In reality,it followed the desired values without oscillations and chattering.

关键词： Supercritical water nuclear reactor Higher order sliding mode controller Steam temperature Steam pressure Point kinetics model

Thermal stability of the Cr-coated zirconium alloy microstructure prepared by pulsed laser deposition

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Tungsten 2024年第2期6卷 333-341页

作者： Bo Li Hui-Long Yang Reuben Holmes Li-Juan Cui Sho Kano Hiroaki Abe Department of Nuclear Engineering and Management The University of TokyoTokyo 113-8656Japan School of nuclear Science and engineering Shanghai Jiao Tong UniversityShanghai 200240China nuclear Professional School The University of TokyoIbaraki 319-1188Japan

Cr-coated zirconium alloy was prepared by pulsed laser deposition(PLD)for the application of accident-tolerant fuel cladding in light water reactors.The microstructural characteristics of the Cr coating and its evolution with temperature were investigated using grazing incidence X-ray diff raction and in situ heating transmission electron microscopy(TEM).Results show that the microstructure of the laser-deposited Cr coatings consists mainly of fine and non-specific shaped nano-crystals in the inner layer and columnar crystals in the outer layer.The recrystallization of the Cr-coating layer starts at 300–400℃ to release the high strain introduced by PLD,and the grain coalescence starts at temperatures>400°C.Upon annealing,the(110)-texture gradually intensifi es because of its high reticular density and low close-packed energy.Additionally,in situ heating TEM observation shows the presence of cavities on the Cr–Zr interface,which may result from the interdiff usion and/or the transformation from amorphous to crystalline.

关键词： Accident tolerant fuel Crcoating Interface Microstructure Pulsed laser deposition

Loss of offsite power (LOOP) accident analysis by integration of deterministic and probabilistic approaches in Bushehr-1 VVER-1000/V446 nuclear power plant

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nuclear Science and Techniques 2022年第5期33卷 39-52页

作者： Mohsen Esfandiari Gholamreza Jahanfarnia Kamran Sepanloo Ehsan Zarifi Department of Nuclear Engineering Science and Research BranchIslamic Azad UniversityTehranIran Reactor and nuclear Safety School Nuclear Science and Technology Research Institute(NSTRI)TehranIran

The results of an accident analysis for the loss of offsite power(LOOP)scenario in a reference Bushehr-1 VVER-1000/V446 nuclear power plant(NPP)are presented in this paper.This study attempted to provide a better analysis of LOOP accident management by integrating deterministic and probabilistic approaches.The RELAP5 code was used to investigate the occurrence of specific thermal–hydraulic phenomena.The probabilistic safety assessment of the LOOP accident is presented using the SAPHIRE software.LOOP accident data were extracted from the Bushehr NPP final safety analysis reports and probabilistic safety analysis reports.A deterministic approach was used to reduce the core damage frequency in the probabilistic analysis of LOOP accidents.The probabilistic approach was used to better observe the philosophy of defense in depth and safety margins in the deterministic analysis of the LOOP accident.The results show that the integration of the two approaches in LOOP accident investigations improved accident control.

关键词： Loss of offsite power Deterministic Probabilistic Integration RELAP5 SAPHIRE

Shielding and corrosion properties of the Alloy 709 as canister material for spent nuclear fuel dry casks

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Defence Technology（防务技术） 2023年第3期21卷 116-124页

作者： Zeinab Y.Alsmadi Mohamed A.Bourham Department of Nuclear Engineering North Carolina State UniversityRaleighNC 27695-7909USA

The shielding and corrosion properties of the Alloy 709 advanced austenitic stainless steel have been investigated as a candidate canister material in spent fuel dry casks.The results revealed that the experimental and computational data of the linear and mass attenuation coefficients of the alloy are in good agreement,in which the attenuation coefficient values decreased with increasing photon energy.Alloy 709 was shown to exhibit the highest linear attenuation coefficient against gamma rays when compared to 304 and 316 stainless steels.On the other hand,Alloy 709 exhibited no considerable weight change over a 69-day period in circulating salt brines corrosion testing,while it showed an exponential increase of corrosion current density with temperature in acidic and basic corrosive solutions during electrochemical polarization corrosion testing.Furthermore,Alloy 709 was the least corroded steel compared to other austenitic stainless steels in both acidic and basic solutions.The optimistic results of the shielding and corrosion properties of Alloy 709 due to its chemical composition,suggest utilizing it as a canister material in spent nuclear fuel dry casks.

关键词： corrosion steel austenitic

Machine learning of metal-ceramic wettability

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Journal of Materiomics 2022年第1期8卷 195-203页

作者： So Yeon Kim Ju Li department of Materials Science and engineering and department of nuclear Science and engineering assachusetts Institute of TechnologyCambridgeMA02139USA

The adhesion and wetting between metal and ceramic is a basic problem in materials science and engineering.For example,past materials selection for metal-ceramic composites has relied on random trials and heuristics due to a limited understanding of their adhesion;the large chemical/structural variability that such interfaces can have hinders the identification of the governing factors.Here based on literature data,we have developed a database with~1,000 experimentally measured wetting angles at different temperatures and atmospheric conditions,and come up with a model for the wettability of ionocovalent ceramics(ICs)by metals using a machine learning(ML)algorithm.The random forest model uses the testing temperature and~40 features generated based on the chemical compositions of the metal and the ceramic as predictors and exhibits strong predictive power with an R^(2) of~0.86.Moreover,this model and the featurization code are integrated into a single computational pipeline to enable(1)predicting metal-IC wettability of interest and(2)high-throughput searching of ICs with the desired wettability by certain metals in the entire Inorganic Crystallographic Structure Database.As a demonstration of this pipeline,the wettability of a Li-ion and electron insulator(LEI),CaO,by molten Li is estimated and compared with ab initio molecular dynamics simulation result.This ML pipeline can serve as a practical tool for methodical design of materials in systems where certain metalceramic wettability is desired.

关键词： Metal-ceramic wettability Wetting angle Machine learning High-throughput screening Solid-state batteries

Mesh‑free semi‑quantitative variance underestimation elimination method in Monte Caro algorithm

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nuclear Science and Techniques 2023年第1期34卷 157-171页

作者： Peng‑Fei Shen Xiao‑Dong Huo Ze‑Guang Li Zeng Shao Hai‑Feng Yang Peng Zhang Kan Wang department of engineering Physics Tsinghua UniversityBeijing 100084China China nuclear Power engineering Corporation Beijing 100840China

The inter-cycle correlation of fission source distributions(FSDs)in the Monte Carlo power iteration process results in variance underestimation of tallied physical quantities,especially in large local tallies.This study provides a mesh-free semiquantitative variance underestimation elimination method to obtain a credible confidence interval for the tallied results.This method comprises two procedures:Estimation and Elimination.The FSD inter-cycle correlation length is estimated in the Estimation procedure using the Sliced Wasserstein distance algorithm.The batch method was then used in the elimination procedure.The FSD inter-cycle correlation length was proved to be the optimum batch length to eliminate the variance underestimation problem.We exemplified this method using the OECD sphere array model and 3D PWR BEAVRS model.The results showed that the average variance underestimation ratios of local tallies declined from 37 to 87%to within±5%in these models.

关键词： Monte Carlo algorithm Power iteration process Inter-cycle correlation Variance underestimation Sliced Wasserstein distance

Understanding the connection between blasting and highwall stability

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International Journal of Mining Science and Technology 2019年第1期29卷 99-103页

作者： R.Quentin Eades Kyle Perry department of Mining and nuclear engineering Missouri University of Science and Technology

Surface mines continue to implement highwalls for several reasons, such as increasing recovery, improving margins, and justifying higher stripping ratios. Highwall stability is a complex issue that is dependent upon a variety of mining and geologic factors, and a safe design is necessary for a successful surface operation. To improve highwall stability, it is important to understand the connection between local geology and blasting. Explosives are employed throughout the mining industry for primary rock breakage. There are a number of controlled blasting techniques that can be implemented to improve highwall stability.These include line drilling, smooth wall blasting, trim blasting, buffer blasting, air decking, and presplitting. Each of these techniques have associated advantages and disadvantages. Understanding local geology is necessary for selecting the appropriate controlled blasting technique. Furthermore, understanding the limitations and conditions for successful implementation of each technique is necessary. A discussion of the impact of geologic conditions on highwall stability is provided. Additionally, discussion is provided for the successful incorporation of the controlled blasting techniques listed above, and the associated mining and geologic factors that influence the selection and design of controlled blasting plans.Finally, a new methodology is proposed.

关键词： Controlled blasting Highwall stability Presplitting Surface mining

Evaluation of the 20 L dust explosibility testing chamber and comparison to a modified 38 L vessel for underground coal

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International Journal of Mining Science and Technology 2018年第6期28卷 885-890页

作者： Robert Eades Kyle Perry Catherine Johnson Jacob Miller department of Mining and nuclear engineering Missouri University of Science and Technology

The phenomenon of combustible dust explosions is present within many industries. Tests for explosibility of dust clouds per ASTM E1226 use a 20 L explosive chamber that places the combustible dust directly below the dispersion nozzle which generates a thorough mixture for testing purposes. However, in the underground coal mining industry, there are a number of geologic, mining, and regulatory factors that change the deposition scheme of combustible coal dust. This causes the atmosphere of a coal mine to have a variable rock dust-coal dust mixture at the time of ignition. To investigate the impact of this variable atmosphere, a series of lean explosibility tests were conducted on a sample of Pittsburgh Pulverized coal dust. These explosibility tests were conducted in a 38 L chamber with a 5 kJ Sobbe igniter. The 38 L chamber generates a variable air-dust mixture prior to ignition. The test results indicate that the 38 L chamber experiences reduced explosive pressures, and lower explosibility index values when compared to the 20 L chamber.

关键词： Dust explosion Coal mining Coal dust Explosibility testing

Impulse force reductions and their effects on WBV exposures in high impact shovel loading operations

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International Journal of Mining Science and Technology 2018年第3期28卷 423-435页

作者： Danish Ali Samuel Frimpong Mining & nuclear engineering department Missouri University of Science and Technology

When shovels load the dump trucks with over 100-ton passes under gravity dumping conditions, they will create a large impact force on the dump truck body which generates high frequency shock waves which expose the operators to whole body vibrations(WBV). The main cause of such truck vibrations is the large impact force due to the gravity dumping of large tonnage passes. Therefore a rigorous mathematical model has been developed for the impact force containing all the necessary factors upon which it depends. Latter, a thorough analysis shows that percentage reduction of 7.19%, 9.40%, 13.27%, 14.8%,17.30% and 18.13% can be achieved by reducing the dumping distance to 6.33 m, 6.0 m, 5.5 m, 5.33 m,5.0 m and 4.9 m, respectively, as compared to when the dumping distance was 7.33 m. Even more reduction in the magnitude of impact force can be observed if the shovel pass gets divided into more than two sub-passes. Therefore, these models can be used to figure out the number of sub-passes into which a single ore pass can be divided and/or the extent to which the dumping distance can be reduced which would reduce the impact force significantly enough to obtain safer yet economic operations.

关键词：操作员装载数学模型通行证垃圾场倾倒罐头卡车

Enhancing manual P-phase arrival detection and automatic onset time picking in a noisy microseismic data in underground mines

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International Journal of Mining Science and Technology 2018年第4期28卷 683-691页

作者： Mborah Charles Ge Maochen department of Mining and nuclear engineering Missouri University of Science and Technology

Accurate detection and picking of the P-phase onset time in noisy microseismic data from underground mines remains a big challenge. Reliable P-phase onset time picking is necessary for accurate source location needed for planning and rescue operations in the event of failures. In this paper, a new technique based on the discrete stationary wavelet transform(DSWT) and higher order statistics is proposed for processing noisy data from underground mines. The objectives of this method are to(i) improve manual detection and picking of P-phase onset; and(ii) provide an automatic means of detecting and picking P-phase onset time accurately. The DSWT is first used to filter the signal over several scales. The manual P-phase onset detection and picking are then obtained by computing the signal energy across selected scales with frequency bands that capture the signal of interest. The automatic P-phase onset, on the other hand, is achieved by using skewness-and kurtosis-based criterion applied to selected scales in a time-frequency domain. The method was tested using synthetic and field data from an underground limestone mine. Results were compared with results obtained by using the short-term to long-term average(STA/LTA) ratio and that by Reference Ge et al.(2009). The results show that the method provides a more reliable estimate of the P-phase onset arrival than the STA/LTA method when the signal to noise ratio is very low. Also, the results obtained from the field data matched accurately with the results from Reference Ge et al.(2009).

关键词：时间频率顺序统计石灰石矿数据获得信号偏斜度参考书 STA