The Loss of Coolant Accident (LOCA) is one of the most serious accidents in nuclear power plants. According to the requirements of the United States Nuclear Regulatory Commission (USNRC) SPR, the dynamic response anal...
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The seismic design of the reactor coolant pump is important for the nuclear power plant. In this study, the magnetorheological fluid damper (MRF damper) is introduced to the supporting structure of reactor coolant pum...
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The reactor coolant system (RCS) is the primary system of the nuclear power plant primary cycle. Some small module reactors (SMR) applied once-through steam generator and integrated reactor vessel. The characteristic ...
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reactor system modeling is the premise of reactor control system design. The common commercial thermal and hydraulic analysis programs like RELAP5, RETRAN have complex structure and slow operational speed, which are n...
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The dynamic analysis of reactor coolant system is the key step of mechanics evaluation, and with the continuous improvement of seismic design benchmarks and system design requirements, it is urgent to carry out the re...
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Understanding the evolution of microstructures in nuclear fuels under high-burn-up conditions is critical for extending fuel refueling cycles and enhancing nuclear reactor *** this study,a phase-field model is propose...
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Understanding the evolution of microstructures in nuclear fuels under high-burn-up conditions is critical for extending fuel refueling cycles and enhancing nuclear reactor *** this study,a phase-field model is proposed to examine the evolution of high-burn-up structures in polycrystalline UO_(2).The formation and growth of recrystallized grains were initially *** was demonstrated that recrystallization kinetics adhere to the Kolmogorov–Johnson–Mehl–Avrami(KJMA)equation,and that recrystallization represents a process of free-energy ***,the microstructural evolution in UO_(2) was analyzed as the burn up *** bubbles acted as additional nucleation sites,thereby augmenting the recrystallization kinetics,whereas the presence of recrystallized grains accelerated bubble growth by increasing the number of grain *** observed variations in the recrystallization kinetics and porosity with burn-up closely align with experimental ***,the influence of grain size on microstructure evolution was *** grain sizes were found to decrease porosity and the occurrence of high-burn-up structures.
The topological magnetoelectric effect (TME) is a hallmark response of the topological field theory,which provides a paradigm shift in the study of emergent topological ***,its direct observation is yet to be realiz...
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The topological magnetoelectric effect (TME) is a hallmark response of the topological field theory,which provides a paradigm shift in the study of emergent topological ***,its direct observation is yet to be realized due to the demanding magnetic configuration required to gap all surface ***,we theoretically propose that axion insulators with a simple ferromagnetic configuration,such as the MnBi2Te4/(Bi2Te3)nfamily,provide an ideal playground to realize the *** the designed triangular prism geometry,all the surface states are magnetically *** a vertical electric field,the surface Hall currents give rise to a nearly half-quantized orbital moment,accompanied by a gapless chiral hinge mode circulating in ***,the orbital magnetization from the two topological origins can be easily distinguished by reversing the electric *** work paves the way for direct observation of the TME in realistic axion-insulator materials.
In pressurized water reactor(PWR),fretting wear is one of the main causes of fuel assembly ***,the operation condition of cladding is complex and harsh.A unique fretting damage test equipment was developed and tested ...
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In pressurized water reactor(PWR),fretting wear is one of the main causes of fuel assembly ***,the operation condition of cladding is complex and harsh.A unique fretting damage test equipment was developed and tested to simulate the fretting damage evolution process of cladding in the PWR *** can simulate the fretting wear experiment of PWR under different temperatures(maximum temperature is 350℃),displacement amplitude,vibration frequency,and normal *** fretting wear behavior of Zr-4 alloy under different temperature environments was *** addition,the evolution of wear scar morphology,profile,and wear volume was studied using an optical microscope(OM),scanning electron microscopy(SEM),and a 3D white light *** show that higher water temperature evidently decreased the cladding wear volume,the wear mechanism of Zr-4 cladding changed from abrasive wear to adhesive wear and the formation of an oxide layer on the wear scar reduced the wear volume and maximum wear depth.
Attitude planning of rigid bodies has many applications in robotics and aerospace. However, because the attitude configuration space is non-Euclidean and the constraints are complex and non-linear, the design of the a...
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Attitude planning of rigid bodies has many applications in robotics and aerospace. However, because the attitude configuration space is non-Euclidean and the constraints are complex and non-linear, the design of the attitude curve has always been a tricky problem. In this paper, a gradient-based attitude planning method is proposed to simultaneously handle attitude pointing, angular velocity, torque, and time constraints on Lie group SO(3). Firstly, the attitude interpolation algorithm on SO(3) gives an attitude curve connecting the initial and target attitudes. The shape of the curve is determined by the fitting coefficients and maneuvering time. Secondly, to match the curve with suitable angular velocity and control torque, a nonlinear planning model with fitting coefficients and maneuver time as decision variables is proposed. Solving the problem gives a smooth attitude curve that satisfies both kinematic and dynamic constraints and also avoids complicated time allocation. Then, to apply the gradientbased solver, analytical formulas for the derivatives of each order of the attitude curve with respect to the decision variables are given in this paper. Finally, the effectiveness of the proposed algorithm is verified by a series of numerical simulations.
Al/Ni reactive multilayer foil(RMF)possesses excellent comprehensive properties as a promising substitute for traditional Cu bridge.A theoretical resistivity model of Al/Ni RMF was developed to guide the optimization ...
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Al/Ni reactive multilayer foil(RMF)possesses excellent comprehensive properties as a promising substitute for traditional Cu bridge.A theoretical resistivity model of Al/Ni RMF was developed to guide the optimization of ***/Ni RMF with different bilayer thicknesses and bridge dimensions were prepared by MEMS technology and electrical explosion tests were carried *** to physical and chemical reactions in bridge,the electrical explosion process was divided into 5 stages:heating of condensed bridge,vaporization and diffusion of Al layers,intermetallic combination reaction,intrinsic explosion,ionization of metal gases,which are obviously shown in measured voltage *** of interface and grain boundary scattering on the resistivity of film metal were *** on variations of substance and state,the resistivity was developed as a function of temperature at each *** explosion curves were calculated by this model at different bilayer thicknesses,bridge dimensions and capacitor voltages,which showed an excellent agreement with experimental ones.
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