AP1000电站保护和安全监控系统预运行测试分析

在AP1000电站中,保护和安全监控系统是基于Common Q平台设计的安全级仪控系统。为确保电站运行前保护和安全监控系统满足系统设计功能要求,采用交叠测试方法对保护和安全监控系统进行了预运行测试。结合保护和安全监控系统的结构和功能,对保护和安全监控系统预运行测试进行介绍和分析,供预运行测试时参考。

AP1000非能动堆芯冷却系统再循环管道预运行试验研究

再循环管道预运行试验通过测量管道两端压差和流量确定阻力,需要考虑止回阀开度随流量变化而变化的特性,进而影响管道总阻力。再循环管道中使用文丘里流量计来代替爆破阀,作用是测量各段支管的流量和总流量,结合止回阀特性曲线计算得到止回阀开度和阻力,迭代计算得到再循环管道阻力。试验借用安全壳内置换料水箱的重力注射,避免地坑淹没。再循环管道试验的设计采用不同流量工况来验证对应的管道阻力,得到流量—阻力对应关系,作为预运行试验阻力验收准则。

日本“文殊”快堆预运行试验开始

【《日本原子》1991年5月号第4页报道】日本动力堆核燃料开发事业团(PNC)耗资约600亿日元建造的文殊原型快堆已于1991年5月18日开始进行预运行试验。这座快堆充分利用了日本自己的技术和通过国际合作得到的资料。“文殊”是日本的第一座发电快堆,受到了日本国内外人士的关注。这次预运行试验将持续到8月份。

复杂大电网非预设性运行工况下的继电保护动作适应性仿真分析

非预设性运行工况下的突发事件多,导致继电保护逻辑的适应性较差,不合理区域较多,为此,进行复杂大电网非预设性运行工况下继电保护动作适应性仿真分析。分析历史常规故障,标记故障点最常发生位置,构建零序、负序方向元件模型、距离元件模型、纵联电流差动元件模型,观察复杂大电网非预设性运行工况下的电网参数变化情况,第一时间掌握电网的耦合性,不断选择电网所需的继电保护动作逻辑,确认继电保护动作适应性。仿真实验表明,将故障点设置在保护区域内和区域外,继电保护动作能够根据故障选择不同保护模型进行故障母线切除或者保护不动作,适应性好。

茭陵泵站改造工程机组启动预试运行方案研究

针对茭陵泵站改造工程的特殊性,在机组试运行前进行预试运行方案研究。进行了运行参数测试、抽水能力检查、应急演练及供电能力测试等项工作,并分析处理了系统运行情况及存在问题,提出茭陵泵站工程试运行的方法、程序,达到了优化试运行方案的目的,确保工程项目目标的实现。

输气管道系统试运行准备的探讨

针对输气管道系统试运行前的清管、测径、试压、排水和干燥等工作的流程和参数选择问题,文章结合上海液化天然气项目海底输气管线工程实例,通过对工程实践的数据和相关设计标准的比较分析,结合工程具体情况合理选择技术参数,为管道系统运行做准备。

机构运动仿真的可行性与可行域研究

计算机动态仿真技术已经广泛应用于机构的研究和设计中,对机构进行运动仿真,在动态显示前,需要对原动件作周期运动的整个过程,即组成机构的所有构件的运动位置进行分析计算,得到机构在做周期运动过程中所有构件均满足和不满足装配条件的原动件位置信息,该过程可称作机构仿真的预运行,将满足装配条件的区域称为可性域。由此提出了机构运动仿真的可行性概念。这样,在运动仿真演示时,显示的是机构在可行域内的连续运动。该理论的提出对于生产中机构运动情况的分析与问题解决、以及机构的优化设计等具有重要意义。

初始腐蚀产物对水冷聚变堆源项影响的研究

水冷聚变反应堆在首次临界之前,会经历一段时间的热工水力和水化学参数的调试,称为预运行阶段。在此期间,冷却回路的金属材料与高温高压且非中性的冷却剂接触过程中,会被氧化而产生初始的腐蚀产物。这些腐蚀产物会沉积在回路内表面,在反应堆物理启动后被中子活化形成活化腐蚀产物(简称ACPs),进而影响反应堆正式运行期间的放射性源项。本文首先依托ACPs源项分析程序CATE和ITER包层冷却回路例题,对初始腐蚀产物的影响进行了定量分析,结果表明:初始腐蚀产物含量越多,反应堆运行相同时间后产生的ACPs比活度越大;与非辐照区的初始腐蚀产物相比,辐照区的初始腐蚀产物对ACPs影响更大。随后,基于经典的浓度差驱动模型,推导了ACPs比活度与初始腐蚀产物的解析关系式,揭露了不同区域初始腐蚀产物对ACPs的影响机理,得到以下定性分析结论:辐照区与非辐照区的初始腐蚀产物对ACPs比活度有一定影响,但影响程度不同,验证了数值解的结论。

AP1000堆芯补水箱排水与自动卸压系统喷放合并试验的研究

在非能动核电厂的首次启动中,需要执行一次预运行试验项目,以验证核电厂系统运行与设计相一致,非能动安全系统(PXS)预运行试验需要验证已安装的部件和相关的管道、阀门能正确的执行设计要求的安全功能。在试验规程中,CMT排水试验与ADS喷放实验分别进行。考虑到这两个试验中都有ADS阀门开启,本文采用系统分析程序针对试验合并的可行性进行研究,论证从热工水力现象模拟的角度试验合并的可行性,以达到简化试验流程的目的。

AP1000核电站氢气系统施工和调试要点分析

AP1000核电站氢气系统与其他核电氢气系统的区别就是,氢气系统既要向除盐水除氧提供低压氢气,又要向一回路直接注入高压氢气以维持还原性水化学环境;它们的共同点就是都向发电机提供冷却用氢气。本文介绍了在系统移交和调试试验过程中遇到的问题,针对这些问题,调试队所采取的良好实践进行简要介绍。

PMS设备误触发风险控制分析

结合保护和安全监测系统的功能和结构特点,对PMS响应时间预运行测试方法进行了分析,指出了测试过程中的设备误触发风险并给出了解决方案,最终消除了测试过程中的设备误触发风险。

Collaborative prediction for bus arrival time based on CPS

To improve the accuracy of real-time public transport information release system, a collaborative prediction model was proposed based on cyber-physical systems architecture. In the model, the total bus travel time was divided into three parts: running time, dwell time and intersection delay time, and the data were divided into three categories of historical data, static data and real-time data. The bus arrival time was obtained by fusion computing the real-time data in perception layer together with historical data and static data in collaborative layer. The validity of the collaborative model was verified by the data of a typical urban bus line in Shanghai, and 1538 sets of data were collected and analyzed from three different perspectives. By comparing the experimental results with the actual results, it is shown that the experimental results are with higher prediction accuracy, and the collaborative prediction model adopted is able to meet the demand for bus arrival prediction.

The Nonlinear Interaction Process in the Wave Assimilation Model and Its Experiments

This paper presents a composite interaction formula based on the discrete-interaction operator of wave-wave nonlinear interaction for deriving its adjoint source function in the wave assimilation model. Assimilation experiments were performed using the significant wave heights observed by the TOPES/POSEIDON satellite, and the gradient distribution in the physical space was also analyzed preliminarily.

Operating speed models for curved segments of highways in plateau regions

To examine the influence of the harsh environment in plateau areas on the operating speed of vehicles,advanced speed prediction models for curved segments are established based on observed actual speed data.First,the speed characteristics at the starting,mid,and end points of a plane curve were observed on Lalin Highway and China National Highway 318 with Bushnell s handheld radar speedometer 10-1911CN.Second,the stepwise regression method was proposed to determine the significant parameters and propose the prediction models of the operating speed of cars and large vehicles for the two highways.Finally,reserved test group data were utilized to prove the validity and practicality of the proposed models.Compared with traditional methods,the established models can produce more accurate prediction results and deeply examine the nonlinear relationships between parameters and the predicted operating speed.This study provides a considerate direction and basis for the operating speed prediction model for other segments in plateau regions.

Model of the Reliability Prediction of Masonry Walls in Buildings

The suitable repair forecasting is needed for proper maintenance of the buildings. The appropriate maintenance planning should be based on the prognostic analysis of the repair needs. However, in Poland, maintenance planning is currently not seen as a long-term system. Repairs are understood as extemporary work and are carried out exclusively on the basis of intermittent inspections and controls. One of the numerous factors determining maintenance planning is exploitation reliability conditioned by durability. This article presents a proposal to determine the prediction of operational reliability of the building constructed using traditional technology. The method of behaving and changing the reliability of the building throughout its use will be useful in planning renovations. The presented analysis includes apartment buildings erected in a traditional technology and regards them as technical objects. For such approached buildings, it is proposed to apply rules applied for mechanical and electrical objects. The probability of the exploitation of a building without any breakdowns in a given period of time is defined as exploitation reliability.

Prediction of Planing Craft Motion Based on Grey System Theory

In order to minimize the harm caused by the instability of a planing craft, a motion prediction model is essential. This paper analyzed the feasibility of using an MGM（1,N） model in grey system theory to predict planing craft motion and carried out the numerical simulation experiment. According to the characteristics of planing craft motion, a recurrence formula was proposed of the parameter matrix of an MGMfl,N） model. Using this formula, data can be updated in real-time without increasing computational complexity significantly. The results of numerical simulation show that using an MGM（1,N） model to predict planing motion is feasible and useful for prediction. So the method proposed in this study can reflect the planing craft motion mechanism successfully, and has rational and effective functions of forecasting and analyzing trends.

China's Optimal Industrial Structure:Theoretical Model and Econometric Estimation

With analysis of producer's and factor supplier's dual optimization motives,this paper developed an optimal nominal output growth rate model that can conduct quantified estimation.Result of estimation of China's optimal industrial structure between1992 and 2009 indicates that optimal nominal output growth rate model has successfully quantified the impact of major events occurring in the process of China's economic operation on the level of deviation between actual industrial structure and optimal industrial structure.Quantitative indicators involved in this model can provide industrial policy instruments for the Chinese government in developing and adjusting industrial structure targets,optimizing resource allocation and advancing industrial structure optimization and upgrade.

English professional football players concussion knowledge and attitude

Background： Concussions are a common pathology in football and multiple misconceptions exist amongst the players and managers. To address these misconceptions, and potentially reduce concussion associated sequela, effective educational interventions need to be developed. However, the current knowledge and attitude status must be ascertained to appropriately develop these interventions. The purpose of this study was to assess the concussion knowledge and attitude of English professional footballers. Methods： Twenty-six participants from one English Football League Championship club completed the study. A mixed methods approach included the Rosenbaum Concussion Knowledge and Attitudes Survey （RoCKAS） and a semi-structured interview. The RoCKAS contains separate knowledge （055） and attitude （15-75） scores and was followed by a semi-structured interview consisting of concussion knowledge, attitude, and behavior related questions. Results： The mean score on the RoCK.AS knowledge was 16.4± 2.9 （range 11-22） and the attitude score was 59.6 ± 8.5 （range 41-71）. The interview responses identified inconsistencies between the RoCKAS and the intended behaviors, endorsing multiple concussion misconceptions, and revealed barriers to concussion reporting. Conclusion： The results of this study suggest that Championship Level English footballers have moderate concussion knowledge, safe attitudes, and good concussion symptom recognition when assessed with pen and paper questionnaires. However, within the semi-structured interview many respondents reported unsafe concussion behaviors despite accurately identifying the potential risks. Further, multiple barriers to concussion reporting were identified which included perceived severity of the injury, game situations, and the substitution rule. These findings can help form the foundation of educational interventions to potentially improve concussion reporting behaviors amongst professional footballers.

Analysis of Electrical and Non-electrical Causes of Variable Frequency Drive Failures

VFDs （variable frequency drives） are an integral part of many industrial plants and stations. Reliable operation and maintenance of these drives is vital to ensure sustained plant operation and availability. Understanding of the principles of operation of VFD systems as well as knowledge about their required operating environment is necessary for all operating personnel. Many times the operating personnel do not get involved with different technical issues until a complete failure has occurred. Hence, the awareness of the most dominant failure causes has a significant impact on assisting operators to avoid catastrophic failures and tremendous economic losses due to VFD shutdown. Proper plant design, accurate monitoring and data logging, following manufacturer preventive maintenance schedule, and choosing qualified team of operators can be the key to an efficient operation and a long lifetime for any VFD system. In this paper, we have analyzed the electrical and non-electrical causes of VFD failures based on a case study of a typical medium voltage VFD pumping station. Finally, recommendations are given from field analysis and observations.

An algorithm for trajectory prediction of flight plan based on relative motion between positions

Traditional methods for plan path prediction have low accuracy and stability. In this paper, we propose a novel approach for plan path prediction based on relative motion between positions(RMBP) by mining historical flight trajectories. A probability statistical model is introduced to model the stochastic factors during the whole flight process. The model object is the sequence of velocity vectors in the three-dimensional Earth space. First, we model the moving trend of aircraft including the speed(constant, acceleration, or deceleration), yaw(left, right, or straight), and pitch(climb, descent, or cruise) using a hidden Markov model(HMM) under the restrictions of aircraft performance parameters. Then, several Gaussian mixture models(GMMs) are used to describe the conditional distribution of each moving trend. Once the models are built, machine learning algorithms are applied to obtain the optimal parameters of the model from the historical training data. After completing the learning process, the velocity vector sequence of the flight is predicted by the proposed model under the Bayesian framework, so that we can use kinematic equations, depending on the moving patterns, to calculate the flight position at every radar acquisition cycle. To obtain higher prediction accuracy, a uniform interpolation method is used to correct the predicted position each second. Finally, a plan trajectory is concatenated by the predicted discrete points. Results of simulations with collected data demonstrate that this approach not only fulfils the goals of traditional methods, such as the prediction of fly-over time and altitude of waypoints along the planned route, but also can be used to plan a complete path for an aircraft with high accuracy. Experiments are conducted to demonstrate the superiority of this approach to some existing methods.