针对热分层现象的稳压器波动管结构评价方法研究及分析程序应用开发

稳压器波动管热分层现象对核电厂安全运行具有潜在威胁。根据热分层发生机理,采用Fr数来判断热分层现象是否发生,研究热交换系数的计算方法,并将热分层引起的三维热应力解耦成一维总体应力和二维局部应力。根据RCC-M规范的要求,采用一维和二维组合的应力计算方法,将热分层产生的应力和其他载荷产生的应力叠加,进行结构完整性评定。配套本文提出的分析评价方法,对SYSTUS程序和ROCOCO程序进行应用开发。采用本文的分析评价方法和配套的分析程序,对秦山二期扩建工程稳压器波动管热分层进行分析评价,结果表明:稳压器波动管在热分层效应下结构完整性仍然满足RCC-M规范要求。     

非能动氢复合器的应力分析和评定

非能动氢复合器是核电站重要的安全屏障,能够避免核电站因氢气积聚而引发的燃烧和爆炸。在福岛核事故之后,国内外核电站更加重视非能动氢复合器的作用。本文主要研究非能动氢复合器在地震和LOCA工况下的应力状态。利用有限元软件ANSYS建立模型,合理考虑LOCA工况下气流载荷对结构的影响,最后按照RCC-M规范进行评定。结果表明,该结构满足RCC-M规范的相关要求。本文可以为非能动氢复合器应力分析与评定提供参考。     

EPR安全壳高能管道贯穿件应力分析

介绍了EPR机组安全壳高能管道贯穿件的结构特点,并对该类型贯穿件的应力分析方法做了重点描述。高能管道贯穿件的应力分析一般分为两个步骤:首先进行热分析,得到结构的温度分布,并判断温度是否满足安全壳混凝土的温度限值要求;第二步进行热-机械耦合分析,得到结构在各种工况下的应力分布,最后根据RCC-M规范的具体要求进行贯穿件应力的评定。分析过程中考虑结构的轴对称特征,采用平面模型进行简化。本文结合具体算例,采用ANSYS程序进行建模计算分析,并采用RCC-M规范进行了高能管道贯穿件的应力评定。     

反应堆压力容器承压热冲击分析研究

依据RCC-M规范和美国NRC 10CFR50.61,对存在假想裂纹的反应堆压力容器堆芯带区进行承压热冲击分析研究.计算核电厂寿期末的基准温度,并采用承压热冲击筛选准则进行评定;计算了承压热冲击瞬态作用下裂纹尖端的应力强度因子,并按RCC-M规范进行评定.     

二代改进型核电站管道系统应力分析与评定

管道是核电站中的重要部件。为了使管道满足规范要求,需要对管道进行应力分析与评定。本文分析了二代改进型核电站1级和2级管道应力分析与评定过程,论述了不同载荷下管道应力的计算方法,并分析了RCC-M规范版本的变化对管道应力分析结果的影响。最后,以岭澳核电站二期工程安全注入系统为例,对管道进行了应力分析与评定,满足了RCC-M规范的设计要求,并输出了支撑载荷、接管载荷、管道位移等接口参数。本文可以为二代改进型核电站管道系统应力分析与评定提供帮助。     

基于APDL的反应堆压力容器接管三维应力和疲劳分析方法

应用ANSYS参数化设计语言(APDL)编制程序,对反应堆压力容器接管的应力和疲劳分析过程进行优化,快速得到接管的应力分布状况、最大应力及疲劳使用系数,并按照RCC-M规范进行评定.     

核级管道的应力分析

管道是核反应堆中重要的部件。本文介绍了核电站管道系统应力分析评定过程,即利用管道系统应力分析程序SYSPIPE,对管道承受的自重、内压、热膨胀、地震等载荷进行计算,根据RCC-M规范进行应力分析和评定。核级管道的应力分析不仅可以保证管道、支架、设备的安全,且可以优化设计,在核电站建造和运行中起到很重要的作用。     

核电站用车载式废树脂接收装置研制

为保证核电站放射性废树脂及时安全排放,本文研制了一套车载式废树脂接收装置,该装置具有移动式和一体化等特点,能在低温恶劣环境下实现废树脂接收的功能。研制过程中,利用有限元分析软件ANSYS建立了装置的三维计算模型,对装置进行了模态分析和响应谱分析,得到了装置在设计工况下各载荷组合后的应力强度,并基于有限元分析结果根据RCC-M规范规定的应力准则对装置结构进行了应力强度评定。结果表明：装置在设计工况下符合RCC-M规范O级准则的强度要求。试验验证结果证实,该车载式废树脂接收装置满足废树脂接收和安全运输的要求。     

控制棒驱动机构耐压壳下部密封环应力与疲劳分析

采用有限元分析方法对某核电工程控制棒驱动机构耐压壳下部密封环的2种对接厚度进行了应力和疲劳分析对比,在疲劳分析中采用瞬态分组技术,同时参考RCC-M 2002规范对ANSYS程序中的弹塑性修正因子(Ke)进行解耦修正。结果表明,2种接头厚度的分析结果均满足RCC-M规范中的应力评定准则,其中,较薄密封环结构疲劳分析结果相对更安全,较厚密封环结构在其余工况相对更安全;在疲劳分析中对瞬态进行分组能明显降低使用系数和一次加二次应力之和幅值的保守性;在热和机械共同作用的一次加二次应力之和的幅值较高时,对Ke的修正能明显提高计算结果精度。     

ANSYS在核级管道应力分析中的应用

ANSYS是国际通用的大型有限元分析软件,具备管道应力计算的功能。SYSPIPE是法国FRAMATOME公司开发的专用于核级管道系统的应力计算和分析程序。利用ANSYS与SYSPIPE对核2级管道承受自重、内压、热膨胀、地震等载荷进行计算对比,选用RCC-M设计规范进行应力分析和评定。结果表明,ANSYS可以替代SYSPIPE对核级管道进行应力分析。     

Construction of Flowmeter for Fluorine

A flowmeter for F₂ using nickel filament as sensing element was constructed. The design is in most part similar to the Katharometer used in gas chromatography. The output voltage of the flowmeter was measured for Ar, N², O² and F² for flow rates between 0 and 400m//min at filament currents in the range 50–75 mA. The dependence of output on the thermal conductivity of the gas being measured and on the filament current are briefly discussed. The temperature of the filament was calculated from the measured values of resistance.     

基于CFD分析的文丘里流量计设计优化

质量流量是核电站热功率核算的关键参数之一,核电站一般采用文丘里流量计和孔板流量计同时测量,然而在低流量区文丘里流量计呈现出明显波动,其参数不稳定严重影响核电站的正常运行。本文基于理论分析结合数值分析,发现脉动流动是导致文丘里流量计测量波动的主要原因。基于分析结果,对文丘里流量计提出了优化设计方案,通过在文丘里管上游集成流量调整装置,从而减小脉动流,有效提升文丘里流量计的稳定性。此外,开展了集成不同类型流量调整装置的文丘里流量计压损特性数值研究,结果表明K-Lab型流量调整装置阻力较小。本文提出的方案可有效提升文丘里流量计测量精度。     

Numerical evaluation of SmCo permanent magnet flowmeter measuring sodium flow in a low flow rate regime using FLUENT/MHD module

One of the several key subsystems in the test facility of Korean sodium-cooled fast reactor is a plugging meter system, which measures the impurities in the sodium using an indirect online technique. To measure the low flow rate, a permanent magnet flowmeter was developed owing to its inherent fast response time, non-invasive characteristic, relatively accurate flow rate measurements, and excellent linearity between the flow rate and flowmeter signal. However, several limitations have been reported in the experimental evaluation of the flowmeter under low flow rate conditions given the measurement capability of the current experimental facility. Thus, the performance of the flowmeter was evaluated numerically using a commercial computational fluid dynamics tool, a FLUENT/MHD module, based on the finite volume method with the help of electromagnetic analysis software, ANSYS MAXWELL. The FLUENT/MHD module was validated by comparing the simulation results with the experimental results. The relative error of the FLUENT simulation was estimated to be approximately 0.24% compared with the experimental results. After the validation process, MHD simulations were conducted to calculate the flowmeter voltage signals versus flow rates, especially in a low flow rate regime, where the linearity between the flow rate and flowmeter signal was carefully analyzed.     

华龙一号小幅功率提升研究

对华龙一号热功率精度进行了分析,计算了蒸汽发生器出口压力测量精度、给水温度测量精度和给水流量测量精度对华龙一号热功率精度的贡献度,通过定量化的数据证明了主给水流量测量精度对热功率计算精度的影响最大。基于目前孔板流量计精度低,长期使用精度劣化的问题,提出采用高精度（0.3%）的超声波流量计来测量主给水流量,计算结果表明,采用超声波流量计可以获得0.97%的功率提升。      

精密钛涂层测厚仪

本文介绍一种用微机控制的精密钛涂(镀)层厚度测定仪,测量范围为0.1—10μm,最小测量面直径为3mm,精度优于±5％。     

The Calibration and Stability of a 1200°F Permanent Magnet In-Core Sodium Flowmeter

A previously described, permanent magnet (PM), in-core flowmeter for use in sodium cooled reactors has been fabricated and installed in the Argonne National Laboratory (ANL) Sodium Flowmeter Calibration Loop. The calibration test facility and procedures are described and a typical family of flowmeter calibration curves are presented. The measured sensitivity is compared to that theoretically predicted and the discrepancies are discussed. Long term performance of the flowmeter is discussed.     

Cell Flowmeter for Turbulent Velocity Fluctuation Measurements in Water

Based on the discovery that electrolytic currents vary with changes in flow velocity, the authors have developed the “cell flowmeter”. The principal applicability of the cell flowmeter has been demonstrated by experimental results revealing: (1) Variation of electric resistance between electrodes with changing flow velocity, (2) responsiveness to oscillations in flow rate, (3) distinctly difficult patterns of records obtained from turbulent and laminar velocity profiles, (4) response to artificial disturbances applied to the flow at near critical Reynolds number. The power spectral density of longitudinal velocity fluctuations was analyzed for a pipe flow of water, and proved to resemble that obtained for air by other authors. The cell flowmeter has advantage of simplicity, high sensitivity and above all applicability to ordinary tap water.     

Flowrate monitoring in an RBMK process channel on the basis of coolant activity information

A method of determining the coolant flowrate in an RBMK process channel on the basis of activity information is examined. A mathematical model of coolant activation in the RBMK channel and an algorithm for determining the flowrate in the channel with an imprecise flowmeter are described. The results of tests of the computational-measurement system to determine the coolant flowrate in the No. 1 unit of the Kursk nuclear power plant are presented (area of application and error in flowrate determination).     

Performance evaluation of eddy current flowmeter in Monju

Measurement of the temperature and flow rate at each fuel subassembly outlet is an effective way for a liquid metal fast breeder reactor to detect a loss of coolant accident or reactivity-initiated accident in the early stage and to understand the reactor’s thermal hydrodynamic performance. Japan Atomic Energy Agency has developed the eddy current flowmeter in practical use and installed 34 of them in the upper core structure of fast breeder reactor, Monju. This report presents data obtained by using the flowmeters in Monju. We observed high linearity between each of the flowmeter’s signal intensity and the primary sodium’s flow rate under 10–100% flow rate condition. High linearity was also observed in a region of low velocity (approx. 0.25 m/s). The fluctuation of flow rate observed by the flowmeters was below 0.2 m/s which is 5% of the time-averaged velocity under a rated condition. These experimental results show that the eddy current flowmeter is an effective tool to detect the changes in relative flow rate.     

Actual flow calibration of a feedwater flowmeter using a high Reynolds number facility at NMIJ

The results of calibration tests of the feedwater flowrate of ultrasonic flowmeters used in a nuclear power plant for variety of upstream conditions obtained using the new high Reynolds number calibration facility at NMIJ are described. In this examination, the measurements are performed for five pattern pipe layouts with one or two elbows. The flow conditioners installed upstream of the flowmeter are the tube bundle type and the Mitsubishi, which are normally used in nuclear power plants. The calibration result for each flowmeter are largely different for each flow conditioner and each upstream pipe layout, except in some special cases. Moreover, the trend of the correction factor with Reynolds number is not uniform for each case. Furthermore, some differences were observed for individual flowmeters. It is recommended that the feedwater flowmeter, especially when used to perform measurement uncertainty recapture, is calibrated based on the actual pipe layout and the Reynolds number corresponding to the actual nuclear power plant conditions.