共查询到20条相似文献,搜索用时 203 毫秒
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研究了相变材料(冰)围绕水平圆柱,在有限长接触时的压力熔化过程。应用边界层理论和冰水的热物性求得熔化边界层厚度、作用力与熔化速度关系式。并与长圆柱的压力熔化和有限长圆柱以及球体的温差熔化的结果进行了比较,给出一些有益的结论。 相似文献
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抛物体核废料容器自埋过程中传热问题的研究 总被引:13,自引:3,他引:10
对装有核废料的抛物体容器在地球引力的作用下,依靠其放出的热量将其周围介质熔化而进行的自埋过程进行了研究,利用边界层理论,对熔化区的液体传热与运动进行了分析,求得容器的自埋速度与表面温度,并对影响它们的诸因素进行了讨论。 相似文献
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正在研制一个感应加热熔化系统,以得到一种高减容和高温度的稳定产物且对放射性核素有好的包容。这个系统用预先安放在感应加热熔化炉的陶瓷罐本身的热量,它被称为内罐(in-can)型陶瓷罐。因此,这个熔化固化系统可适用于由几种不同类型组成的不可燃固体废物的处理。 相似文献
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彗星实验图像分析中彗星分割阈值的选择 总被引:1,自引:0,他引:1
彗星实验(单细胞凝胶电泳)图像自动分析中,彗星轮廓的合理分割是后续各项指标分析的前提。首先采用几种常用的图像边缘检测算法对彗星轮廓进行提取,并分析了彗星图像的特点;然后对文献中提到的和现有彗星分析软件(如CASP、TfiTek Comet Score TM)中的彗星轮廓分割方法进行比较;最后采用一种基于图像内容的阈值分割方法,实现了最佳阈值的选择,并得出了彗星轮廓分割的几点原则。 相似文献
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Simulations of heat transfer in UO2 at very high temperatures incorporating the effects of phase transitions are being conducted to help support the design and analysis of experimental work being conducted as part of nuclear safety research. This work includes the interpretation of the behaviour of nuclear fuel under conditions where centerline melting may occur. Models based on the Stefan formulation and Phase Field approach are derived from fundamental principles and implemented using recently published material properties. Both simulations compare well with laser flash experiments in recently published literature. The Phase Field model is recommended for further development due to its versatility in handling heat sources and robustness in simulating the evolution of the solid-liquid interface. These points are demonstrated with an example simulation of centerline melting resultant from fission heating for fuel performance analysis. 相似文献
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针对HPR1000堆型堆芯熔融坍塌问题建立了精确的三维堆芯模型,使用时间推进方法通过求解熔融物的瞬态运动、传热微分方程,确定熔融物在堆芯中的瞬态位置和瞬时温度,以模拟堆芯升温及堆芯熔融进程。研究结果表明:停堆后约2 400 s开始出现熔融现象,熔融物在堆芯活性区域内下落且发生多重相变过程;在4 900 s后,熔融物在堆芯底部形成约1.5 m高的稳定熔池;由于外围组件与低温围栏装置换热,最外围的组件不会发生熔融。本文建立的堆芯熔融物运动与传热分析模型及相关计算结果,可为事故缓解和处理提供技术参考。 相似文献
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Ali F. AbuTaha 《Journal of Fusion Energy》1990,9(3):345-349
The assumption that deuterium, and not palladium, is the fuel in the Pons-Fleischmann experiments led to high expectations of cold nuclear fusion. The conversion of mechanical energy to heat was neglected in studying the phenomenon. Considerable strain energy is stored in metals when processed from the ore. The initiation, growth, and propagation of cracks in the bulk disturb the energy balance within the metal. Deuterium induces and propagates cracks in metals and alloys, including palladium. The sudden discharge of fracture energy during crack propagation generates considerable heat. The abundance of deuterium in cracked palladium will not continue the heat-generation process. The confident figures-of-merit of cold fusion have been based on the small energy input to the electrolytic cells and do not consider the substantial energy required to process (by melting) the palladium from the ore, or to recycle the cracked electrode samples. In this paper, the work-of-fracture is shown to be the likely mechanism responsible for the excess heat in cold fusion.This and related work have been fully sponsored by the author; Technical Consultant, 2868 Spring Chapel Court, Herndon, Virginia 22071. 相似文献
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温度是影响熔岩玻璃体溶解速度的关键因素,为此,本文计算了核试验后10~300 000d内熔岩玻璃体中核素衰变热功率,评估了核素衰变热功率对熔岩玻璃体的温度和溶解速度的影响程度。采用了国际原子能机构给出的100kt TNT当量地下核试验产生的、半衰期大于1a的放射性核素含量,利用其中裂变产物核素137 Cs的含量推算累积裂变产额大于0.1%、半衰期为1d~1a的短寿命裂变产物核素的含量。分析了各核素的放射性衰变特点,采用ENDF/BⅦ库中核素衰变辐射的平均α能量、平均电子能量和平均电磁辐射能量计算各核素在熔岩玻璃体内因衰变而沉积的能量。计算结果表明:核素衰变热功率呈分段幂函数衰减;在10~2 000d、2 000~60 000d和60 000d之后的时段内,衰变热功率分别主要源于短寿命裂变产物核素、长寿命裂变产物核素和锕系元素。核素衰变热功率对熔岩玻璃体的温度和溶解速度的影响不大,1 000d后影响非常小。 相似文献
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文章提出最小核临界事故源项的分析模型,并给出了相关计算方法,利用MCNP程序计算了不同易裂变材料以及不同物料状态下,发生最小核临界事故时的总裂变次数和中子伽马吸收剂量比等源项参数。通过与已发表文献和已有相关数据进行对比,结果符合良好。 相似文献
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Yosuke Kawamoto 《Journal of Nuclear Science and Technology》2017,54(2):213-222
The accurate prediction of the decay heat is essential, especially for nuclear power plant safety purposes. However, it is known that the decay heat predicted by nuclear fuel burn-up calculations is uncertain because of uncertainty of nuclear data employed in the calculations. If the decay heat uncertainty can be reduced, the safety margin of the predicted decay heat can also be reduced, and feasible design ranges of various types of equipments related to the decay heat can be extended. In the present study, we use the nuclear data adjustment method for the decay heat uncertainty reduction with several types of the experimental data. As a result, we clarify that the decay heat uncertainty with short- and long-term cooling periods can be reduced by this method with appropriate experimental data. 相似文献
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The design of new reactors such as ADS has been investigated in many countries during the last years for burning transuranic nuclides (TRUs) contained in spent reactor fuel. To increase the TRU incineration rate, fertile-free dedicated fuels, which may contain a large fraction of minor actinides (MAs), are currently considered. Based on past experience, R&D activities for dedicated fuels in Europe concentrate on fuel forms, in which the oxide actinide phase is mixed with oxide or metal inert matrices. Decay heat in a system with inert matrix fuel (IMF) containing MAs may differ from that in a conventional fast reactor. In this paper, several fast reactor designs with different TRU content are considered and related decay heat values, calculated on the basis JEFF 3.0 and JEFF 3.1 nuclear data libraries, are compared. It is shown that some decay heat components for fuels with MAs may be lower than those for MA-free fuels, but the total decay heat may be significantly higher for cooling times exceeding about 1 min. 相似文献
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在分析~(252)Cf中子源辐照钚部件产热机理基础上,应用MC法计算了钚部件裂变热功率以及~(252)Cf源γ射线能量沉积热功率;建立理论模型,计算了钚部件冷却过程中衰变热。相比自发衰变热功率,典型中子源强照射下钚部件的热效应并不严重。利用缓发γ能谱近似模型,计算了拟人体外照射剂量。与国际放射防护委员会(ICRP)建议值相比,典型中子源强照射下操作人员接受的辐射剂量在安全范围内。 相似文献
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从乏燃料的不同燃耗引起放射性和化学组成的变化出发,分析乏燃料经后处理后的衰变热、Mo及贵金属含量对玻璃固化工艺和玻璃固化体储存的影响,计算得到了不同燃耗乏燃料制得的高放玻璃的数量。计算结果认为:对于冷却8 a的乏燃料,决定玻璃固化体包容量的不是高放主组分的热功率;对于燃耗小于40 GW•d/tU的乏燃料,决定玻璃固化体包容量的是Mo元素含量;当燃耗大于45 GW•d/tU时,贵金属含量成为决定玻璃固化体包容量的主要因素,同时UO2燃料燃耗与高放玻璃固化体数量上存在线性关系,燃耗增加会导致高放废物玻璃固化体数量增加。随着燃耗的增加,以Mo含量及贵金属含量计算得到的玻璃固化体数量比以衰变热计算得到的玻璃固化体数量多,因此,高放废物玻璃固化前将Mo及贵金属进行分离有利于减少高放废物玻璃固化体数量。对于UO2燃料,燃耗加深对于高放废物玻璃固化体暂存时间几乎无影响。 相似文献