高温气冷堆燃料装卸监控系统改造

基于HTR-10燃料装卸系统的设计和监控要求,完成了燃料装卸和燃耗测量自动流程设计,分别采用CPT梯形图、FIX组态及REXX脚本等方式编制了PLC用户程序、上位机监控程序及燃耗测量控制程序,在此基础上采用上位机组态的监控模式完成了监控系统及其与上位机的通信设计,实现了对燃料装卸监控系统的改造.现场调试结果表明,改造后的监控系统功能完整、界面友好,提高了燃料装卸运行效率和可靠性.     

10kV配电网故障定位系统研究与应用

在整个电力系统中,配电网处于最末端的位置,运行过程中的故障直接影响着供电的安全性、可靠性及电能质量,与电力用户用电关系密切,所以研究配电网故障点的迅速查找与隔离有着巨大的现实意义。本文针对10kV配电网接地短路故障设计了一种新型的配电网故障定位系统,简述了该系统的设计理念与实现,以及故障自动定位过程。运行实践证明,这一系统在10kV配电网发生故障后,能够快速的帮助检修人员准确的找到故障点。     

频标自动测量系统数据库的设计与实现

为了实现对频率标准的自动测量和测量结果的自动存储、生成证书,开发了一套频率标准自动测量系统,设计并实现了一套嵌入在时间标准装置与频标自动测量系统中的数据库管理系统.本系统采用模块化设计思想,具有占用系统资源少、运行速度快等优点.经过测试,所设计的数据库管理系统能够满足频率标准自动校准系统工作的需要.     

EAST低温系统超临界氦循环泵的自动控制

为确保EAST超导磁体安全、稳定地进行降温,通过分析超导磁体氦迫流冷却回路并结合低温系统降温操作流程,在低温控制系统中设计并实现了氦循环泵的自动启动和失超处理等顺序控制流程;采用选择性控制结构和改进的增量式PID控制算法,实现了氦循环泵入口压力的自动控制.经过降温实验验证,氦循环泵的自动控制策略满足低温系统的运行要求,在一定程度上提高了系统的自动化程度.     

基于影像的内燃机曲轴随动自动检测技术

为实现内燃机曲轴关键几何尺寸的快速、自动、精密测量,研发了一种基于影像测量原理的内燃机曲轴随动自动精密检测系统.介绍了测量原理及系统方案,包括光学成像系统的设计与选型、4轴随动机械结构的设计方案等;介绍了系统检测流程以及面向曲轴特征影像的核心图像处理算法及特征提取技术;进而提出了光学成像系统的标定方法,并对标定过程中的难点设计了解决方案;进行系统集成,开发了曲轴检测样机,并开展工程应用.应用结果表明,本技术实现了对曲轴沟槽及直径参数的快速、自动、精密检测.     

10kV配电线路设计技术中的关键问题简析

随着我国社会经济的快速发展,电力事业得到了长足的发展,作为电力输送的关键环节,配电线路在电力系统中扮演着重要的角色。加强对配电线路的合理设计,能够保证电力系统运行的安全与稳定。本文以10kV配电线路设计为例,首先介绍配电线路设计的一般流程,然后探讨10kV配电线路设计要点,供有关人员参考。     

钟罩式气体流量标准装置测量能力提升改造

随着科技的进步,自动采集控制被广泛运用于流量计的检定/校准。文章介绍了在原有的钟罩式气体流量标准装置基础上对装置测量能力进行升级改造,基本实现自动化测量。改造内容主要包括:装置部分、检定管路系统、稳压恒温气源系统、自动控制系统等。通过对装置压力系统进行改进,以减少钟罩在运行过程中的压力波动,保障钟罩运行平稳;通过研制检定管路系统,实现流量计的快速安装;设计制造稳压恒温气源系统保障介质压力和温度的稳定;设计制造自动控制系统和编制校准软件,实现校准过程自动控制和原始记录报表的自动生成等。     

谈10KV高压开关柜交接试验

随着电力技术的发展,10kv高压开关柜总体制造质量及运行可靠性有了较大的提高,故障率也大大降低,但在我国高压开关柜交接试验中存在许多问题。如何有效地控制开关柜交接试验设计不当、时间过长、效应低造成的困扰,是本文主要论述的问题,意在为10kv高压开关柜交接试验方法探究与改进提供一些合理的建议。     

机场变10kV配电系统的改造方法分析

在机场中,供电与配电系统极为关键,是机场运行安全性、服务质量的重要保证,其中,变10kV配电系统必不可少。本文基于现阶段机场变10kV配电系统中存在的一些问题,将相应的改进建议提出,以期使机场供电与配电质量得到进一步提升,进而促进机场服务品质的提升。     

测试/校准实验室卓越绩效综合管理体系设计

根据卓越绩效评价准则,结合测试/校准实验室特点,提出以"五个子系统"和"四个驱动项"为框架,分解战略目标,以测量指标为主线,构建测试/校准实验室卓越绩效综合管理体系。为有效实施该体系,设计测量指标评价体系运行及系统改进流程、绩效测量工作实施流程,建立了创新与改进工作的三维实施模型并提供了活动矩阵。     

Quantification of free-carrier absorption in silicon nanocrystals with an optical microcavity

We present a highly sensitive and accurate microcavity-based technique to quantify the free-carrier absorption (FCA) cross-section of semiconductor quantum-dot ensembles. The procedure is based on measuring the pump-intensity-dependent broadening of the whispering gallery modes (WGMs) of microdisk resonators. We have applied this technique to determine the FCA cross-section of Si nanocrystals (Si-ncs) in the visible-near-infrared wavelength range. Our procedure accounts for the size distribution effects by including the measured wavelength dependence of the excitation cross-section and the decay rate of photoexcited carriers in the analysis. By monitoring the WGM widths at various wavelengths in the 700-900 nm wavelength range, we found that the FCA cross-section follows an approximately quadratic wavelength dependence. The magnitude of the FCA cross-section of Si nanocrystals was determined to be a factor of 7 higher than that in bulk Si. For this reason, these findings have important implications for the design of Si-based lasers and all-optical switching devices in which FCA plays a critical role.     

Thermal Conductivity of Simulated Fuels with Dissolved Fission Products

The thermal diffusivity of simulated fuels with dissolved fission products was measured by using the laser-flash method in the temperature range from room temperature to 1,473 K. Three kinds of simulated fuels with an equivalent burn-up of 3, 6, and 12 at% were used in the measurement. The thermal diffusivity and the thermal conductivity of the simulated fuels with the dissolved fission products decreased, as the temperature and the equivalent burn-up increased. The thermal conductivities of simulated fuels with equivalent burn-ups of 3, 6, and 12 at% were lower than that of UO₂ by 84.70, 67.17, and 44.97% at 300 K and 99.17, 89.88, and 80.56% of UO₂ at 1,473 K, respectively. The difference in the thermal conductivity between the simulated fuel and UO₂ was large at room temperature, and it decreased as the temperature increased. The thermal resistivity of the simulated fuels increased linearly with temperature up to 1,473 K.     

Effects of the centrifugal coating and centrifugal fluidized bed coating methods on the physicochemical properties of sustained-release microparticles using a multi-functional rotor processor

The purpose of the present study was to examine the effect of coating processes on the physicochemical properties of sustained-release microparticles prepared by centrifugal coating (CC) and centrifugal fluidized bed coating (CFC) using a multi-functional rotor processor. Acetaminophen (APAP)-loaded microparticles (DP) were coated with 30% w/w aqueous polymer dispersion of Eudragit® RS (RS) by CC or CFC methods with the apparatus until a dry polymer weight gain of 30%, 60%, 150% and 200% w/w was achieved, and these coated microparticles were abbreviated as CC-DP-RS and CFC-DP-RS, respectively. Both coated microparticles had similar physicochemical properties, but some differences in the drug dissolution behaviors of CC-DP-RS and CFC-DP-RS at lower coating levels were observed. That is, the coated microparticles prepared by CC showed faster release than that by CFC. As a result of dissolution study using Talc seal-coated microparticles and thermal study using differential scanning calorimeter, the rapid dissolution behaviors from CC-DP-RS at the lower coating levels of RS might be due to APAP migration to the coating film during coating due to the weak drying efficacy of the CC method. These findings suggest for the first time that CFC is a suitable method for the coating of functional polymers at lower polymer coating levels, whereas, for the CC method, adjustment of operational conditions (e.g., product temperature, inlet air volume and liquid flow rate) would be required.     

Radiochemical analysis of a sample of mixed uranium–plutonium nitride fuel

Radiochemical analysis of a mixed uranium–plutonium nitride (MUPN) fuel sample irradiated in a BOR-60 reactor was performed. The study was made using the set of procedures developed at the Research Institute of Nuclear Reactors for determining the nuclide composition and gravimetric content of U, Pu, Am, Cm, Nd and other fission products, platinum group metals, and transition metals, including nuclear physical methods, atomic emission spectrum analysis, mass spectrometry for determining the nuclide composition, and isotope dilution mass spectrometry for determining the gravimetric content of nuclides with preliminary radio-chemical separation of fractions of elements by ion-exchange, extraction-chromatographic, precipitation, and distillation methods. The MUPN fuel burn-up was determined from the ratio of the number of atoms of the fission product selected as a burn-up monitor to the number of heavy atoms in the dissolved fuel sample (method of fission product accumulation, MFP). The ¹⁴⁵Nd + ¹⁴⁶Nd sum and ¹⁴⁸Nd were used as burn-up monitors.     

Transient thermodynamic behavior of cryogenic mixed fluid thermosiphon and its cool-down time estimation

Thermosiphon is an efficient heat transfer device by utilizing latent heat of fluid at liquid-vapor phase change. One of the disadvantages of thermosiphon, however, is that the operational temperature range is fundamentally limited from the critical point to the triple point of the working fluid to maintain two phase state. Nitrogen (N₂) and tetrafluoromethane (CF₄) were selected as the mixed working fluid to widen their original operational temperature range. Thermodynamic behavior of mixture and its effect on the cool-down time were investigated. A simple calculation model was proposed to estimate the cool-down time of the thermosiphon evaporator prior to experiments. The calculated results agreed well with the experimental results within 5% error. The cool-down time reduction was not achieved by mixing two components at once due to the separation of mixture. One idea to avoid this problem was suggested in this paper where the estimated cool-down time was reduced 17.8% compared to pure N₂.     

Measurement of the viscosity of HFC 134a in the temperature range 213–423 K and at pressures up to 30 MPa

The viscosity of HFC 134a was measured over the range of temperatures from 213 to 423 K and pressures up to 30 MPa. The experimental method was that of the capillary flow and a closed-circuit high-pressure viscometer was used. The sample fluid was circulated through a stainless-steel capillary from a highpressure plunger system. The constant of the capillary was calibrated against the reference standard, pure water. The viscosity of the sample was calculated from the flow rate, the pressure drop at the capillary, and the capillary constant using the Hagen-Poiseuille equation. Measurements were made at a total of 39 points on eight isotherms. The measurement uncertainty of the viscosities was estimated as ±1.3%. Based on the present results, an empirical equation for the viscosity of HFC 134a has been correlated. The viscosity on the saturation line calculated by the equation compares with experimental viscosity data in other previous studies. There are rather considerable differences among these measurements. Comparisons of the data for HFC 134a with those for CFC 12 show that the viscosity of HFC 134a is similar in magnitude to that of CFC 12 at temperatures around 300 K but is higher at lower temperatures and lower at higher temperatures. The pressure gradients for these two corresponding substances are similar over the entire temperature range.     

Classifier-ensemble incremental-learning procedure for nuclear transient identification at different operational conditions

An important requirement for the practical implementation of empirical diagnostic systems is the capability of classifying transients in all plant operational conditions. The present paper proposes an approach based on an ensemble of classifiers for incrementally learning transients under different operational conditions. New classifiers are added to the ensemble where transients occurring in new operational conditions are not satisfactorily classified. The construction of the ensemble is made by bagging; the base classifier is a supervised Fuzzy C Means (FCM) classifier whose outcomes are combined by majority voting. The incremental learning procedure is applied to the identification of simulated transients in the feedwater system of a Boiling Water Reactor (BWR) under different reactor power levels.     

基于PLC现场总线通讯的NBI真空测量与控制系统设计

针对拟建的NBI综合测试平台,设计了真空测量与控制系统,介绍了系统的结构及功能。根据系统要求及操作规范,以PLC作为控制核心,梯形图作为编程语言,触摸屏作为人机界面,组建了完整的控制系统,以实现自动运行。上位机的组态软件通过RS485总线通讯实现真空系统的自动控制以及真空度的在线实时监测与显示。该控制方案具有硬件简单可靠、组态灵活、软件运行稳定的特点,能够满足NBI对辅助抽气系统的真空测量与控制的要求。