BESⅢ超导磁体失超保护及信号采集

介绍了北京正负电子对撞机上北京谱仪(BESⅢ)的超导磁体失超保护系统的设计原理,重点介绍了基于CAN总线的信号采集系统的设计和实现.信号采集系统监测和记录磁体内部关键电压信号以及磁体外部重要的辅助信号,用于分析和诊断磁体的状态,并用LabVIEW完成用户界面程序设计.     

Development of 5 T NbTi Superconducting Magnet with 160 mm Warm Bore for Magnetic Separation

A wide-bore 5 T NbTi superconducting magnet, for magnetic separator, with an operational current of 106 A is designed and fabricated. This magnet with a Ф60 mm roomtemperature bore is installed in a vacuum cryostat and immersed in liquid helium. A two-stage 4 K Gifford-McMahon （GM） cryocooler is used to maintain the cooling shield at 70 K and the condenser at 4 K in order to achieve the zero vaporization loss of liquid helium. The cooling power of the GM cryocooler is 1.5 W. In this paper, the design, heat leakage, stress analysis, quench protection characteristics and preliminary test results are presented.     

A first characterization of the quench detection system for ITER

The purpose of this paper is to assess the expected response of conventional and non-conventional quench detection sensors proposed for the ITER coils, and to be tested in the QUELL experiment in SULTAN. The assessment is based on simulation of thermohydraulic transients in the ITER coils for various operating conditions, and a tentative definition of the transfer functions of each sensor concept. It is shown that, for the investigated conditions, the co-wound voltage taps are more accurate than hydraulic systems and conventional voltage balance methods. The additional complication associated with the insertion of taps in the conductor is well offset by the low sensitivity to external disturbances.     

圆管通道底部再淹没过程实验研究

为验证和优化再淹没模型,通过实验研究了圆管通道内再淹没阶段流动换热特性,获得了不同工况下壁面温度的变化规律,实验工况范围为：入口冷却剂流速3~15 cm/s、入口过冷度15~75 ℃、初始壁面峰值温度340~600 ℃、实验压力0.2~0.4 MPa、加热功率1.3~2.3 kW/m。分析了初始壁温、冷却剂入口温度、入口流速及加热功率对骤冷时刻与骤冷温度的影响。结果表明,骤冷时刻与骤冷温度均随初始壁温、冷却剂入口温度以及加热功率的增加而增加,随入口冷却剂流速的增加而减小。     

六氟苯(C_6F_6)体系中氧对正子素(Ps)寿命的影响

本工作研究了溶解在六氟苯(C_6F_6)中的氧对正子素(Ps)寿命的影响。分别得到了在C_6F_6中三重态正电子素(O-Ps)的原始摘除寿命τ_3~0=4.15 ns;氧猝灭O-Ps的速率常数k_(O_2)=1.8×10~(10)(1mol~(-1)s~(-1));三重态激发分子~3(C_6F_6)猝灭O-Ps的速率常数k~3(C_6F_6)=1.7×10~(10)(1mol~(-1)s~(-1)),以及六氟苯体系中三重态激发分子~3(C_6F_6)猝灭O-Ps的贡献。结果表明:~3(C_6F_6)对O-Ps寿命的影响并不很大。     

配接MIC-80微机的液体闪烁测量系统中样品化学发光的检测及该系统程序中一些问题的考虑

一、样品化学发光的估算 与淬灭现象相反,样品化学发光在液闪测量中会导致假计数。为此,在每次建立新的样品制备方法之后都需估计该方法是否会导致化学发光,若有,还要估计它对测量结果影响的程度。已有多种检测化学发光的方法报道,但大多有各自的缺点:用不含放射性的对照样品的方法则比较费时间:用双重外标准源道比法需专门绘制一条标准曲线且在淬灭严重时检测有困难;用延迟符合的技术则需要增加电子学线路。在我们的配接了MIC-80微机的YSJ型液闪仪上,当进行化学发光检测时,仪器会自动给出样品化学发光的估算值nc。若nc=0,则可肯定样品无化学发光或者说化学发光对测量结果无影响;若nc≠0,则提示我们,该样品可能有化学发光存     

Analysis of Cable-in-Conduit Conductors＇ DC Performance in Light of Strand＇s Experimental Properties

Conductor qualification will be carried out with four Cable-in-Conduit Conductor （CICC） samples made of superconducting strands. The direct current （DC） performance of these samples will be tested in the SULTAN facility. The critical current densities of the strands can be well simulated by empirical equations. In this paper, a model is illustrated to predict the DC behaviour of the cable in light of the single strand＇s experimental properties. The simulation results were compared with experimental results.     

基于TXS平台的数字化反应堆保护系统实现特性

数字化反应堆保护系统(Reactor Protection System,RPS)作为重大改进项在CPR1000压水堆机组岭澳核电站首次引入,设计方案经历了多次变更和优化,最终伴随着岭澳核电站成功商运后完成了方案固化。本文介绍了基于阿海珐公司提供的安全级数字化仪控平台(TELEPERM XS,TXS)在岭澳核电站反应堆保护系统最终实现方案,进而重点分析反应堆保护系统方案实现特性。上述论述对后续核电站反应堆保护系统方案实现及其国产化研制提供了借鉴和参考意义。     

Correlation of Quench Phenomena for Bottom Flooding during Loss-of-Coolant Accidents

The three quench modes based on the observation with an outside-heated quartz tube experiment, i.e. (1) liquid column type, (2) dryout type and (3) droplet-rewetting type are discussed quantitatively to provide correlations for a reflood analysis code.

For the quench velocity of liquid column type and dryout type, using the data of PWR-FLECHT experiments, a correlation is obtained. This correlation is compared with experimental data and found that it can predict the inverse quench velocity within ±20% accuracy under the following conditions: pressure 1.0–4.1 kg/cm²-a, quench temperature 370~510°C, local subcooling 0~30°C, flow rate 5~25 cm/sec.

For the quench temperature of droplet-rewetting type, a correlation is derived and the prediction from it gives the qualitative agreement with few available data.     

Simulation and test of quench in CICC: The SMES experience

This paper summarizes the work done as part of the U.S. SMES program to simulate quench evolution on the 200 kA CICC developed by the Bechtel Team. As a large-scale CICC with a central tube, this work has led to a number of results applicable to other conductors sharing similarities with the SMES-CICC. The paper presents the evolution in computational models, since 1987 to date, and describes QUIPS, a test intended to validate these computer models. The paper concludes with observations on the directions in the field as perceived by the author.     

Investigation on effects of conductor concepts on 3D quench propagation in superconducting coils using the code system MAGS

Quench propagation is analysed for two different conductor types, foreseen for a Tokamak and a Stellarator type fusion machine, respectively. For the analysis the code system MAGS is used. In the paper MAGS is presented briefly. The analysis considers quench in a small layer wound coil with separate coolant flow in the two layers modelled. Quench is initiated in the first layer and propagates in this coolant channel as well as to the second coolant channel, via heat conduction. Due to the different design, very different front velocities and peak pressures were determined.Presented at the Workshop on Computation of Thermo-Hydraulic Transients in Superconductors, Lausanne, June 6–8, 1995.     

环形燃料棒束再淹没行为实验研究

环形燃料是一种可在维持或提升安全裕度的前提下大幅提高反应堆经济效益的新型压水堆燃料,由于其双面冷却的特点,环形燃料在LOCA再淹没阶段的热工水力行为与传统实心燃料存在显著差异。现有关于环形燃料再淹没行为的实验研究鲜有报道。本研究基于自主设计的高温环形电加热棒建立了环形棒束再淹没实验装置,开展了3×3环形棒束底部再淹没实验研究,探究了环形棒束再淹没典型物理过程及不同工况下再淹没关键参数的变化规律。结果表明,环形棒束再淹没物理过程与传统实心棒束类似,且内外通道的骤冷前沿推进和传热模式变化趋于同步。在同一时刻下,环形棒内外壁面间存在温度梯度。骤冷前沿推进速度随再淹没速度和过冷度的增大而增大,随峰值包壳温度和线功率密度的增大而减小。此外,定位格架在低流速、低过冷度与高壁温工况下能显著提升下游的骤冷前沿推进速度。