共查询到20条相似文献,搜索用时 15 毫秒
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LI Tianshu YANG Yanhua LI Xiaoyan HU Zhihua 《核技术(英文版)》2007,18(4):252-256
A series of experiments of the premixing stage of fuel-coolant interactions (FCI), namely the particles falling into water, were carried out. The force on the particles during the course of falling has been studied. The dropping character of hot particle was influenced by three main parameters, i.e., particle temperature, particle diameter and coolant subcooling that varied over a wide range. A high-speed camera recorded the falling speed of the particle and the moving curves were obtained. The experimental results showed that for the film boiling on the surface of particle and water, the temperature increase of either particle or coolant would slow down the particle falling velocity. The falling velocity of particle in small diameter is lower than that of the bigger particle. The present work can provide an experimental foundation for further investigation of high-speed transient evaporation heat transfer. 相似文献
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LI Tianshu YANG Yanhua YUAN Minghao HU Zhihua 《核技术(英文版)》2007,18(5):311-315
An observable experiment facility for low-temperature molten materials to be dropped into water was set up in this study to investigate the mechanism of the vapor explosion. The effect of the fuel and coolant interaction (FCI) on the vapor explosion during the severe accidents of a fission nuclear reactor has been studied. The experiment results showed that the molten material temperature has an important effect on the vapor explosion behavior and pressure. The increase of the coolant temperature would decrease the pressure of the vapor explosion. 相似文献
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Coupling effect between film boiling heat transfer and evaporation drag around a hot-particle in cold liquid 总被引:1,自引:0,他引:1
Extremely rapid evaporation could occur when high-temperature particles contact withlow-temperature liquid. This kind of phenomenon is associated with the engineering safety and the problems in high-transient multi-phase fluid and heat transfer. The aim of our study was to design and build an observable experiment facility. The first series of experiments were performed by pouring one or six high-temperature particles into a low saturated temperature liquid pool. The particle's falling-down speed was recorded by a high-speed camera, thus we can find the special resistant feature of the moving high-temperature particles, which is induced by the high-speed evaporation surrounding the particles. The study has experimentally verified the theory of evaporation drag model. 相似文献
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Lili Tong 《Journal of Nuclear Science and Technology》2016,53(3):432-438
Liquid lithium served as plasma-facing material for limiters and divertor target plates are useful for the improvement of plasma performances. However, the liquid lithium water interaction is a main concern for the safety of fusion reactors. The assessment of explosion strength is significant to the risk analysis of application of liquid lithium. An experiment of liquid lithium droplet coolant interaction has been conducted. The experimental result indicates that the mass and initial temperature of liquid lithium droplet has a significant impact on the explosion strength. The peak pressure rises with the increase of the mass and the temperature of liquid lithium. Based on the theory of shock wave overpressure and experimental data, an overpressure formula for liquid lithium droplet coolant interaction is fitted by the least-square method. The optimum values of undetermined coefficients are obtained and the model to assess explosion strength of liquid lithium droplet coolant interaction is established. The model is verified by experimental data and proved to be applicable. It reflects the influence of the mass and initial temperature of lithium on the explosion strength and also provides a novel method for the evaluation of explosion strength of liquid lithium droplet coolant interaction. 相似文献
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Jingtan Chen Mingjun Zhong Junfeng Wang Houjun Gong Qingyu Huang 《Journal of Nuclear Science and Technology》2017,54(9):1002-1010
Pouring coolant into molten material provides an efficient method for cooling molten core debris in light water reactor. This coolant jet-melt interaction mode needs to be studied for proposed application and safety concern. The jet breakup pattern and its final depth are crucial factors for efficient cooling. In the present study, the hydraulic penetration behavior of coolant jet is investigated using experimental and numerical approaches. A series of visual experiments are conducted using low-density gasoline as coolant jet and high-density water as molten fuel. The images of jet behaviors and the data of gasoline jet penetration depth are obtained and analyzed. Based on FLUENT15.0 a 3D axisymmetric model is built and Volume of Fluid (VOF) method is used. The hydraulic penetration behaviors of jet and final penetration depth are correctly simulated and analyzed. The fluctuating phenomenon of penetration depth and the effects of various parameters are discussed. Jet velocity and density ratio are key factors to final penetration depth. The conclusions are helpful to understand the parameter influence and the fluctuation mechanism of final penetration depth and substantiate the understanding of the coolant jet hydraulic penetration behavior during coolant jet-melt interaction. 相似文献
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Ning Li 《Journal of Nuclear Materials》2002,300(1):73-81
The thermodynamic basis for controlling oxygen level in lead-bismuth to prevent steel corrosion and coolant contamination is examined. The operational conditions, including the thermodynamic activity of oxygen, cover gas oxygen partial pressure, mixtures of H2 and H2O (steam) to obtain such low oxygen partial pressure (<10−24 atm or around 10−6 wt% in lead-bismuth), and the voltage signals of one type of oxygen sensors (with a solid electrolyte and molten bismuth reference electrode) are calculated. These results provide the guidance to implement the oxygen control technique. 相似文献
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Motivated to understand the pressure-buildup characteristics in a circumstance of a water droplet immerged inside a heavy liquid metal pool, which is a key phenomenon during a Steam Generator Tube Rupture accident of Lead-cooled Fast Reactor,many experiments have been conducted by injecting water lumps into a molten lead pool at Sun Yat-sen University. In order to deepen the understanding of the influence of melt material, this lead experiment was compared with a Lead–Bismuth-Eutectic(LBE) exper... 相似文献
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To characterize the relationship between thermal and hydrodynamic effects on fragmentation of molten metallic fuels, with the interaction of the sodium coolant under a wide range of thermal and hydrodynamic conditions, in this paper, we focus on the fragmentation characteristics of a single molten copper droplet (1 and 5 g) with an ambient Weber number (We a) from 102 to 614 and superheating conditions from 15 to 574°C, which penetrates into a sodium pool at an initial temperature from 298 to 355°C. In our experiments, fine fragmentations of the single molten copper droplets with a high We a were clearly observed even under a supercooled condition that is well below the copper melting point of 1083°C. The dimensionless mass median diameters (D m /D 0) of molten droplets with a high We a are less than the molten droplets with a low We a under the same thermal condition. When We a was approximately >200, the hydrodynamic effect on fragmentation became dominant over the thermal effect under a relatively low superheating condition. For a higher We a range, the comparisons indicated that the fragment sizes of the molten copper droplets had similar distributions to those of copper and metallic fuel jets and stainless steel droplets even with different thermophysical properties and a 1000-fold mass difference, which implied the possibility that the fragment size characteristics of the molten metal jets could be evaluated by the interaction of a single droplet with the sodium coolant without consideration of dropping modes and mass. 相似文献
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A. G. Sheinkman E. L. Rozenbaum M. R. Shkol'nikov Yu. A. Obmelyukhin V. M. Selivanov A. N. Opanasenko S. I. Shcherbakov 《Atomic Energy》1991,71(3):782-784
Beloyarsk Nuclear Power Plant. Special Design Office for Mechanical Design. Power Physics Institute. Translated from Atomnaya Énergiya, Vol. 71, No. 3, pp. 266–268, September, 1991. 相似文献
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The fragmentation process of high-temperature molten drop is a key factor to determine the ratio heat transferred to power in FCIs,which estimates the possible damage degree during the hypothetical severe accident in the nuclear reactors.In this paper,the fragmentation process of melt droplet in FCIs is investigated by theoretic analysis.The fragmentation mechanism is studied when an external pressure pulse applied to a melt droplet,which is surrounded by vapor film.The vapor film collapse which induces fragmentation of melt droplet is analyzed and modeled.And then the generated pressure is calculated.The vapor film collapse model is introduced to fragmentation correlation,and the predicted fragment size is calculated and compared with experimental data.The result shows that the developed model can predict the diameter of fragments and can be used to calculate the fragmentation process appreciatively. 相似文献
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Li Yonghong He Chaohui Zhao Fazhan Liu Gang Liu Jie 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2009,267(1):83-86
Silicon-on-insulator (SOI) technologies have been developed for radiation-hardened military and space applications. The use of SOI has been motivated by the full dielectric isolation of individual transistors, which prevents latch-up. The sensitive region for charge collection in SOI technologies is much smaller than for bulk-silicon devices potentially making SOI devices much harder to single event upset (SEU). In this study, 64 kB SOI SRAMs were exposed to different heavy ions, such as Cu, Br, I, Kr. Experimental results show that the heavy ion SEU threshold linear energy transfer (LET) in the 64 kB SOI SRAMs is about 71.8 MeV cm2/mg. Accorded to the experimental results, the single event upset rate (SEUR) in space orbits were calculated and they are at the order of 10−13 upset/(day bit). 相似文献
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The liquid lithium–lead (PbLi) breeder blanket concept has been explored extensively due to their potential attractiveness. To check and validate the feasibility, the China dual-functional lithium lead test blanket module (DFLL-TBM) system, which is designated to demonstrate the integrated technologies of both He single coolant (SLL: single-cooled lithium lead) and He–LiPb dual-coolant (DLL: dual-cooled lithium lead) blankets, is proposed for test in ITER. One of the key feasibility issues is the impact of liquid metal MHD effect which will influence the pressure drop, flow distribution, and heat transfer in a DFLL-TBM.To reduce MHD effect, an electrically insulating coating is applied onto the inner surface of the flow channel for single coolant blanket. In this work, a preliminary numerical study of MHD flows in a simplified DFLL-TBM model on the single coolant stage has been carried out to assess the performance of such a concept with regard to the above mentioned MHD problems and constraints. The flow distribution and MHD pressure drop of LiPb flow in the SLL stage TBM are analyzed. 相似文献
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Jong Woon Park Author Vitae Byung Gi Park Author Vitae Author Vitae 《Nuclear Engineering and Design》2009,239(12):3161-3170
Integral tests of head loss through an emergency core cooling filter screen are conducted, simulating reactor building environmental conditions for 30 days after a loss of coolant accident. A test rig with five individual loops each of whose chamber is established to test chemical product formation and measure the head loss through a sample filter. The screen area at each chamber and the amounts of reactor building materials are scaled down according to specific plant condition. A series of tests have been performed to investigate the effects of calcium-silicate, reactor building spray, existence of calcium-silicate with tri-sodium phosphate (TSP), and composition of materials. The results showed that head loss across the chemical bed with even a small amount of calcium-silicate insulation instantaneously increased as soon as TSP was added to the test solution. Also, the head loss across the filter screen is strongly affected by spray duration and the head loss increase is rapid at the early stage, because of high dissolution and precipitation of aluminum and zinc. After passivation of aluminum and zinc by corrosion, the head loss increase is much slowed down and is mainly induced by materials such as calcium, silicon, and magnesium leached from NUKON™ and concrete. Furthermore, it is newly found that the spay buffer agent, tri-sodium phosphate, to form protective coating on the aluminum surface and reduce aluminum leaching is not effective for a large amount of aluminum and a long spray. 相似文献
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功率MOS、IGBT单粒子烧毁、栅穿效应模拟实验研究 总被引:2,自引:0,他引:2
建立了利用^252Gf裂片源,模拟空间重离子引起的单粒子烧毁、栅穿效应的实验方法和测试装置,开展了功率MOS器件、IGBT的单粒子烧毁、栅穿效应的模拟试验研究,给出了被试器件单粒子烧毁、栅穿效应的损伤阈值,以及随器件偏置的变化规律。 相似文献
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乏燃料干法后处理中高温熔盐化学工艺过程中存在设备腐蚀问题,以凝固盐层作为容器保护内衬的熔盐冷冻壁技术被认为是一种可行的解决方式。为开展该技术研究,自行研制并搭建了一套硝酸盐(40.0-7.0-53.0wt%Na NO2-Na NO3-KNO3)冷冻壁技术研究实验装置。该装置上熔盐运行温度150-250oC,熔盐最大流量500 L·h-1,循环导热油运行温度5-120oC,导热油流量1.5-15 m3·h-1。目前在该装置上开展了冷冻壁静态形成及平衡维持等工艺研究,实验中采用容器外壁循环导热油冷却换热实现冷冻壁的形成及维持,并试验了冷冻壁技术在熔盐静态工况下应用的工艺条件。冷冻壁形成平均速率可控制在0.2-0.5 mm·min-1。在冷冻壁静态形成过程中,随厚度增大,热交换量逐渐减小,同时冷冻壁层温差逐渐增大,并均呈衰减趋势变化;处于平衡维持状态时,径向温度分布、热流量及冷冻壁厚度均保持稳定,熔盐发热功率即为平衡状态时的热流量,其大小同时与外壁导热油的冷却热流量相等;实验还获得了较理想的静态应用工艺操作条件,为氟化物熔盐冷冻壁的研究及应用积累了经验。 相似文献