Dawning-1000 PROOS Distributed Operating System

PROOS is a distributed operating system running on the computing nodes of massively parallel processing computer Dawning-1000.It is an efficient and easily extendible micro kernel operating system.It supports the Intel NX message passing interface for communication.     

1000kV交流线路长串绝缘子污秽特性的研究

针对我国准备建设的1000 kV电压等级的交流输电线路用的长串绝缘子,按照真型布置进行人工污秽特性研究。其研究内容包括绝缘子串长与50％人工污秽工频耐受电压U50关系；普通型、双伞型绝缘子及异型串的污耐压特性；附盐密度SDD、附灰密度NSDD、上下表面不均匀积污比对污耐压特性的影响等。指出绝缘子串的U50与串长呈非线性趋势；按线性拟合所求取的U50较试验所求取的U50要高1．6％-10．2％；单片绝缘子污耐压随着海拔的增加而下降等。其研究结果对1000 kV交流输电线路工程造价、线路的可靠运行及污秽外绝缘的合理设计具有重要意义。     

1000kV输电线路带电作业保护间隙的研究

为研究1000kV交流输电线路带电作业的保护间隙,确定了它的设计原则和电极结构,根据该保护间隙工频击穿、工频耐压、操作冲击放电试验的结果得出了不同海拔高度下1000kV输电线路带电作业保护间隙间隙距离的最大允许值;在11塔窗中模拟带电作业各实际工况,采用升降法对保护间隙与作业间隙的绝缘配合进行了操作冲击放电试验,验证了保护间隙对带电作业间隙的保护性能,并计算了1000kV带保护间隙带电作业的危险率。最后证明加装保护间隙不仅可提高作业的安全性,而且能有效地减小塔头尺寸。     

CAN总线在分散控制系统中的应用

本文介绍了基于SJA1000的CAN总线在GKS-9000分散控制系统中的应用，给出了整个系统的结构包括硬件配置和软件流程图，同时对通讯协议的制定也做出了详尽的说明。该系统已在多个工程中投入使用，取得了满意的效果。     

Characterization and densification studies on ThO2-UO2 pellets derived from ThO2 and U3O8 powders

ThO₂ containing around 2-3% ²³³UO₂ is the proposed fuel for the forthcoming Indian Advanced Heavy Water Reactor (AHWR). This fuel is prepared by powder metallurgy technique using ThO₂ and U₃O₈ powders as the starting material. The densification behaviour of the fuel was evaluated using a high temperature dilatometer in four different atmospheres Ar, Ar-8%H₂, CO₂ and air. Air was found to be the best medium for sintering among them. For Ar and Ar-8%H₂ atmospheres, the former gave a slightly higher densification. Thermogravimetric studies carried out on ThO₂-2%U₃O₈ granules in air showed a continuous decrease in weight up to 1500 °C. The effectiveness of U₃O₈ in enhancing the sintering of ThO₂ has been established.     

CAN总线式数字化测温系统的设计

针对传统测温系统所存在的缺陷,设计开发了一套基于CAN总线的通用多点数字化测温系统,给出了系统的总体结构框图。该系统硬件部分以DS18B20、CAN总线控制器和AT89S52为核心,其硬件电路主要由温度信号采集电路、CAN总线接口电路和单片机AT89S52外围接口电路组成。软件部分给出了温度信号检测与控制程序流程图。实际运行证明:该系统结构简单,温度控制准确,测量精度高和实时性强,具有很高的实际应用价值。     

Effects of water based Al2O3, TiO2, and CuO nanofluids as the coolant on solid and annular fuels for a typical VVER-1000 core

In this paper, the effect of nanofluids as the coolant on solid and annular fuels for a typical VVER-1000 core is analysed. The considered nanofluids are various mixture composed of water and particles of Al₂O₃, TiO₂, and CuO. The fuel rod is modeled using a CFD code. To validate the calculated results, the present results of solid fuel with nanofluid and pure water are compared with other studies which have been done with visual FORTRAN language, DRAGON/DONJON code, COBRA-EN code and the mentioned analytical approaches have been validated by comparing with the final safety analysis report (FSAR). The comparison of the calculated results shows that the results are in good agreement with other studies. Thus, the accuracy of the validation is satisfactory. Radial and axial temperature distributions in various components of fuel are illustrated. Moreover, the temperature distributions of the fuel, clad and coolant are described for water based Al₂O₃, TiO₂, and CuOnanofluids in solid fuel and annular fuel. The results are compared with base fluid and it is concluded the nanoparticles of Al₂O₃have good properties in comparison with other nanoparticles. By using the nanofluids, the central fuel temperature is reduced and the temperature of the coolant is increased. In addition, by increasing the heated surfaces in annular fuel, the heat flux on these surfaces is reduced, the minimum departure from nucleate boiling ratio (MDNBR) margin is increased, and therefore the critical heat flux can be increased. Finally, it is concluded the use of the annular fuel instead of solid fuel and also the use of the nanofluids as coolant in the core of the reactor, security and efficiency of the nuclear power plant will be increased.     

核电站堆外核测量系统的原理及工程实践

介绍了堆外核测量系统的原理和组成,比较了AP1000与二代加改进型压水堆核电站堆外核测量系统的异同,分析了各自的优缺点,并提出了堆外核测量系统的一个发展方向。     

Thermal–hydraulic modeling of water/Al2O3 nanofluid as the coolant in annular fuels for a typical VVER-1000 core

In this paper, a thermal–hydraulic analysis of nanofluid as the coolant is performed in a typical VVER-1000 reactor with internally and externally cooled annular fuel. The fuel assembly for annular case with 8 × 8 arrays is considered for annular pin configuration. The considered nanofluid is a mixture composed of water and particles of Al₂O₃ with various volume percentages. The fuel rod is modeled using a CFD code. To validate the calculated results, the present results of solid fuel with nanofluid and pure water are compared with other studies which have been done with visual FORTRAN language, DRAGON/DONJON code, COBRA-EN code and the mentioned analytical approaches have been validated by comparing with the final safety analysis report (FSAR). The comparison of the calculated results shows that the results are in good agreement with other studies. Thus, the accuracy of the validation is satisfactory. Moreover, the temperature distributions of the fuel, clad and coolant are described for water/Al₂O₃ nanofluid in solid fuel and annular fuel. It is observed that as the concentration of Al₂O₃ nanoparticles increases, due to higher heat transfer coefficient of Al₂O₃ nanofluid, the temperature of the coolant is increased and the central fuel temperature is reduced. Thus, it improves margin from peak fuel temperature to melting. Finally, it is illustrated the use of the annular fuel instead of solid fuel in core of the reactor, security and efficiency of the nuclear power plant will be increased.     

Latent heat energy storage characteristics of building composites of bentonite clay and pumice sand with different organic PCMs

In the present work, six new kinds of building composite PCMs (BCPCMs), PS/octadecane, BC/octadecane, PS/CA–MA, BC/CA–MA, PS/PEG1000, and BC/PEG1000 composites, were prepared by using vacuum impregnation method. The maximum percent of PCM in the composites was assigned to be 12, 13, 18, 23, 30, and 42 wt%, respectively. The form‐stable BCPCMs were characterized using SEM, FT‐IR, DSC, and TG analysis techniques. The characterization results showed the existence of homogenous dispersion of the PCM into the PBM matrixes. The DSC measurements indicated that the melting temperatures of the form‐stable BCPCMs are in the range of 20–33°C while they have latent heats of melting in the range of about 28–55 J/g. These results make them promising BCPCMs for low temperature‐passive TES applications in buildings. Thermal cycling test indicated that the prepared BCPCMs have good thermal reliability and chemical stability. TG analysis proved that the prepared BCPCMs have good thermal durability. In addition, the thermal conductivity of BCPCMs was enhanced considerably by addition of expanded graphite (EG). The improvement in thermal conductivity of the BCPCMs caused appreciably reduction in their melting times. Copyright © 2014 John Wiley & Sons, Ltd.