The Application and Improvement of Helium Turbines in the EAST Cryogenic System

The helium cryogenic system supplies supercritical helium cooling capacity at 4.5 K for the superconducting magnets in the EAST superconducting tokamak.Four low-temperature helium turbines are used in the 2 kW helium refrigeration system,and their performance and reliability are critical for the continuous operation of the tokamak.The turbines were made by the Helium Mechanics Company in Russia.The start-up process is very unstable,easily broken,and thus testing and improvements are needed.In this paper,we analyze the structure of the helium turbine,make improvements,and describe the testing process and results of the improved helium turbines.Some of the operational experiences during the start-up process and tests are also presented.     

非稳定流场中的大流量测量

本文介绍了非稳定流场中的大流量测量的一种方法。由于管道布置的限制,只能在φ700的管子弯头后1D的位置采用φ12的五孔球形测针作多点测量,再用等环面面积积分方法来确定其流量。此方法进行了实验室验证,并对反应堆主热交换器流量(2000—4000m~3/h)进行了实测。证明此方法是稳妥可靠的,误差为±5%。测量结果已为工程所采用。     

随机填充球床通道内氦气流动特性实验研究

在聚变堆氦冷固态包层氚增殖区,球床通道内氦气流动压降特性对泵功率的设计具有重要意义。以氦冷固态包层氚增殖区为背景,研究了氦气流速、球床颗粒直径及球床通道长度对球床通道内氦气流动压降特性的影响。实验段采用20 mm×20 mm×500 mm的矩形通道,实验中氦气流速为0.1～0.6 m/s,球床颗粒直径为0.5、0.8、1.0、1.5、2.0 mm。实验结果表明,压降与氦气流速以及球床通道长度呈正相关,与球床颗粒直径呈负相关。对比Ergun关系式发现,在球床颗粒直径较小时,Ergun关系式预测值低于实验值,这主要是由于氦气可压缩性的影响。通过动量方程,理论推导出经可压缩性修正的Ergun关系式,结果发现修正后的Ergun关系式预测值与实验值符合良好。本研究为氦冷固态包层氚增殖区设计提供了数据支撑,为球床通道内流动特性的数值模拟提供了验证手段。     

Chemical Tracer Method for Measurement of Flow Rates in Closed Conduits

Thermal output in a nuclear power plant is verified by a calorimetric heat balance on the secondary system of the power plant. The calorimetry involves the precise measurement of the feed water flow rate which should be designed to have ±1:0% of uncertainty. However, the indication of feed water flow rate obtained by a differential pressure measurement across a venturi can be affected by instrument errors, fouling, or a poorly developed velocity profile. These factors can lead to an inaccurate mass flow rate and consequently, an inaccurate estimate of power. The purpose of this study is to develop verification methods with accuracy better than ±0:5% for high-precision flow measurement to be used for measuring feed water flow rate. Such an improvement saves electric power. For a typical Korean nuclear power plant of 1,000MW, 10MW would be potentially saved. This chemical tracer method is a testing process using a tracer, which can be applied to quantify losses in electrical output caused by incorrect measurement of feed water flow rate. This method has a good response to changes in the flow rate. An accuracy better than 0.5% is expected for feed water flow measurement, provided that the feed water system is stabilized during the test.     

压水堆下腔室流量分布数值分析

建立了压水堆下腔室流场的三维数值计算模型,计算了不同环腔厚度和环腔内冷却剂速度条件下,下腔室内冷却剂的流场,分析了环腔厚度和环腔内冷却剂速度对下腔室流向堆芯的流量分布的影响。入口速度不同或环腔厚度不同,在下腔内冷却剂流动形成漩涡的位置、大小和流动速度均会发生改变,导致通过流量孔板通孔的流量分布不同。入口速度较低时,流量孔板上所有通孔的流量分布比较均匀,在平均值附近波动,流量最高的通孔小组出现在边缘处;入口速度较高时,流量明显地呈现出中心高边缘低的特点。通孔小组的流量最大值随着环腔厚度增加由孔板的中心向边缘移动。     

加速器质谱交替测量方法研究

加速器质谱技术由于其测量精度和灵敏度高等特点使其在多个学科得到广泛的应用。随着加速器质谱技术的改进,加速器质谱系统朝着小型化方向发展。本文在中国原子能科学研究院自主研发设计的端电压为300 kV的小型多核素加速器质谱系统的基础上,根据该设备的特点,研发了一套交替测量系统和交替测量方法,实现了对¹⁴C的准确测量。     

基于能量-速度关联技术的裂变产物质量分布测量方法研究

采用能量E-速度v关联技术测量裂变产物碎片的动能和飞行速度能精确测定裂变产物核的质量。本工作主要研究能量-速度关联技术的可行性并解决相关关键技术。实验测量系统由飞行时间测量单元、能量探测器和真空靶室系统组成。实验中用1对微通道板探测器测量粒子飞行时间来确定粒子速度,金硅面垒探测器测量粒子能量。对于~(241) Am放射源5.48 MeVα粒子,飞行时间测量系统时间分辨(FWHM)为186ps,金硅面垒探测器能量分辨(FWHM)为44keV。实验完成了~(252) Cf自发裂变源产物质量分布试测量。初步实验结果显示,裂变产物质量分布在110amu(amu为原子质量单位)的位置时,其质量分辨为1.6amu。     

同位素稀释质谱法在临床参考系统中的应用

测量结果溯源是实现医学实验室标准化最重要的策略,旨在保证不同实验室、不同测量方法、不同型号、不同仪器厂家检测结果的准确可比。参考测量程序用于评价其他测量程序获得的同类被测量值的正确度。同位素稀释质谱法(isotope dilution mass spectrometry, IDMS)是具有高计量学特性的基准方法。本文主要对同位素稀释质谱法在临床参考系统中的应用进行综述,介绍基本原理、定量方式及其不确定度,并结合国际检验医学溯源联合会(joint committee for traceability in laboratory medicine, JCTLM)参考系统数据库,分析同位素稀释质谱法在临床参考系统的应用及最新进展,为临床参考系统、同位素应用以及计量相关工作者提供参考。     

Measuring Method for ABWR Core Flow Rate

Abstract

A measuring method of core flow rate in the Advanced Boiling Water Reactor (ABWR), which equips Reactor Internal Pumps (RIPs) for reactor coolant recirculation, were evaluated by 1/5 scaled model tests and turbulent analyses. The conclusions obtained are as follows:

(1) An interrelationship among RIPs was so weak that ABWR core flow was derived accurately as the summation of the individual RIP flow rate, which was estimated from each pump O-H characteristics (Q: pump flow rate, H: differential pressure head along the RIP's upstream and downstream). Measurement accuracy of core flow was confirmed to meet the requirements for expected ABWR operating conditions. Furthermore, it appeared likely that the requirements should be satisfied even in hypothetical operating states, namely operation with one pump out of service.

(2) It was also confirmed that the turbulent flow analysis was useful to estimate the flow pattern near the RIPs.     

弱耦合体系流致振动计算方法

弱耦合体系的流致振动的流体作用力可分成与结构运动有关的流体力和与结构运动无关的流体作用力.与结构运动有关的流体作用力可用结构的惯性力、阻尼力和刚度力的线性表达,与结构运动无关的流体力用CFD计算流场压力获得.本文介绍了一种计算弱耦合体系流致振动的方法,用该方法计算了秦山Ⅱ期1∶5模型吊篮,计算的结果和实验的结果保持在3.1倍范围内.因此,该方法可用于流致振动实验前的预估.     

用过零极性相关法测量流体流速

利用研制的相关测试系统，借助高精度的热线风速仪作为标定设备，在标准风洞内进行了相关测量的实验研究，实现了利用过零极性相关法测量流体流速，并对测量结果进行了分析。     

锰浴法绝对测量中子源发射率

锰浴法是目前绝对测量中子源发射率（中子源强度）最广泛、精度最高的方法之一。将已知活度的⁵⁶Mn溶液倒入锰池中,通过两路NaI(Tl)探测器测量锰液中⁵⁶Mn的γ计数,确定系统效率,然后通过锰液饱和活化计数得到中子源强度。利用锰浴法中子源强度标准装置绝对测量了标准²⁴¹Am-Be(α, n)中子源的强度。该中子源是国际电离辐射咨询委员会组织的国际比对CCRI(Ⅲ)-K9.AmBe的传递标准源。测量结果与比对平均值在不确定度范围内一致,验证了本标准装置的可靠性。     

A Disturbance Wave Instability Model for Annular-to-intermittent Flow Transition in Vertical Two-phase Flow System

A model is developed to describe the transition from annular flow to intermittent flow in a vertical two-phase flow system. Since the instability of the disturbance wave, which is a dominant wave shape at the boundary between annular flow and intermittent flow, is considered as a governing mechanism, this instability described by the concept of hyperbolicity breaking in the characteristic equation is included in the model. The developed model is validated by comparing its predictions of gas superficial velocity for the transition with experimental data available in the literature, and comparing those with the predictions of the other correlations. The comparison results show that the model gives better predictions for the transition condition than existing correlations, and the effects of fluid properties, geometry and liquid flow rate on the transition are well considered by the developed model. The average of prediction errors is 3% for the present model. The standard deviation of the prediction errors of the model reaches 28%, which is the smallest among the models compared here.     

加速器质谱测量60Fe方法的模拟研究

长寿命的放射性核素⁶⁰Fe在天体物理学等许多研究领域中有重要科学意义。利用高能量的HI-13串列加速器质谱（AMS）系统和高性能的Q3D磁谱仪,初步研究了⁶⁰Fe的测量方法。通过优化测量条件,利用⁵⁸Fe和⁵⁸Ni分别模拟⁶⁰Fe和⁶⁰Ni,获得了仪器压低同量异位素的能力。结果表明,通过ΔE-Q3D系统结合四阳极气体电离室技术,将Ni的干扰压低了10¹¹。化学方法压低Ni的干扰为10⁴。可以预测⁶⁰Fe/Fe的探测灵敏度为10^-15。     

基于Labview的相关法测量钠流量系统设计

为满足中国实验快堆(CEFR)一回路主泵旁路钠流量计校准的需求,设计了1套基于Labview软件的相关钠流量测量系统。本文介绍了相关法的测量原理、设计的相关钠流量测量系统、对该系统的仿真试验和钠回路上的验证试验。试验结果表明,这套基于Labview的相关钠流量测量系统是可行的。本文还进行了该系统的测量误差分析,给出了减小误差的方法。该系统及其试验为CEFR一回路主泵旁路钠流量计在役校准装置的设计、调试和运行提供了依据。     

氦气试验回路中的氦净化

为了减少结构材料的腐蚀并验证高温气冷实验堆中的氦净化工艺，在氦气试验回路中设置了氦净化系统并进行了试验。试验结果表明，净化流量为５０ｍ＾３／ｈ的主要由分子筛和深活性炭床组成的氦净化系统，能把氦中２００００ｃｍ＾３／ｍ＾３的化学杂质净化到７６ｃｍ＾３／ｍ＾３以下。所采用的氦中痕量杂质分析测量技术达到１０＾－１ｃｍ＾３／ｍ＾３精度。     

中国先进研究堆氦气系统的设计

介绍了中国先进研究堆（CARR）氦气系统的方案调研、工艺流程设计、设备管道阀门布置设计和系统设计难点及特点。在系统布置设计中，采用PDSOFT pining配管软件建立该系统的三维模型，模型形象直观，既利于系统设计审查和修改，又利于现场安装工作。     

Investigation on the Relation of CICC Stability Margin to Mass Flow Rate and Operating Temperature of Helium

1. IntroductionThe conductor which is used for thermonuclear fusion reactors must guarantee high current density,excellent transient stability and mechanical stabilityof the magnet structure. The application of CICChas provided these advantages for the design alldconstruction of superconducting magnets, Experimental results of the stability margin of CICC madeby ITER show that the stability margin is largelydependent on operating mass flow. The numericalsimulation was performed with the s…     

钚质量的量热法测量

量热计是核保障领域中核材料衡算非破坏性直接测量最方便和最准确的仪器之一。本工作应用一种测量钚的热功率范围为0.1～15W的量热计测量了3个²³⁸Pu含量已知的钚样品。²³⁸Pu质量测量值与参考值相对偏差均在-1.7%以内。     

用于高灵敏度AMS10Be测量的气体探测器

¹⁰Be是加速器质谱（AMS）测量中重要性仅次于¹⁴C的核素,在第四纪地质研究等方面发挥着重要作用。为更好地开展岩石暴露年龄测定和黄土中¹⁰Be浓度测量等应用研究,北京大学加速器质谱（PKUAMS）在深入研究离子鉴别物理过程的基础上,设计研制了1台气体探测器,¹⁰Be高能端测量效率达90%以上,¹⁰Be粒子计数率明显增加。在离子源引出只有1.2μA（最大值可达2μA）的情况下,标准样品NIST的¹⁰Be粒子计数率已达23s^-1。