脉冲堆热工水力设计程序研制开发

介绍了中国核动力研究设计院自主开发的脉冲堆热工水力设计程序系统。它包括脉冲堆自然循环分析程序（MC－FLOW）、堆芯热工水力分析程序（MC－THAS）和脉冲堆瞬态分析程序（MC－TRAN）。采用原型堆的数据对程序进行验证，其结果表明：脉冲堆热工水力设计程序系统满足热工水力设计的要求，能够可靠地用于西安脉冲堆的设计。     

线性子链法在脉冲中子活化计算中的应用

核聚变装置大多在脉冲工况下运行,不同的脉冲运行模式会对材料活化计算产生影响,脉冲的处理方法以及活化计算方法的选择直接决定了计算结果的精度。本文采用线性子链法和解析解公式计算反应链中各核素的数量随时间的变化情况,并通过回溯算法搜索所有参与计算的反应链。针对脉冲中子活化问题,将真实脉冲通过稳态（SS）方法、等效稳态（ESS）方法、连续脉冲（CP）方法进行等效处理,从而简化计算过程,并在此基础上编制了用于脉冲中子活化计算的TACT程序。最后基于天然Fe活化基准题,根据惯性约束聚变装置（IFE）和磁约束聚变装置（MFE）的典型脉冲周期对TACT程序进行测试计算,比较了各种脉冲处理方法的准确度。结果表明：对于IFE和MFE的典型脉冲运行模式,以ESS为前段的CP方法的准确度均优于其他方法;对于CP方法,只需适当保留末尾的真实脉冲数即可达到一定的精度。     

脉冲堆元件的焊接

脉冲堆用的7种元件的密封包装是通过焊接来完成的。本文以燃料元件为主,着重对焊接设备,焊接工艺及质量检验进行了介绍,同时还介绍了脉冲氩弧焊和氦弧堵孔焊的工艺。     

焊后热处理对SA517 Gr.F焊接接头力学性能与组织的影响

为更好地掌握焊后热处理（PWHT）对SA517 Gr.F调质钢焊接接头性能的影响,对SA517 Gr.F调质钢手工电弧焊（SMAW）焊接接头进行了焊态（AW）与PWHT试样力学性能和组织分布特征的对比分析研究。分析结果表明:PWHT与AW相比,焊接接头室温拉伸和360℃高温拉伸的抗拉强度均有所下降;焊缝和热影响区（HAZ）峰值硬度降低。PWHT降低了焊接接头的残余应力,但未能改善焊缝和HAZ的冲击性能。建议对于SA517 Gr.F调质钢若满足ASME规范案例N-71-18条件,可免除焊后热处理。      

SFEL电子枪

研制了一台用于自由电子激光用户装置（ＳＦＥＬ）的射频毫微秒脉冲电子枪，其脉中电流为１Ａ，脉冲宽度为１ｎｓ（半宽度－０．７ｎｓ），脉冲重复频率为４７６ＭＨｚ，采用会聚型Ｐｉｅｒｅｅ三枪电子枪，阳极电压１００ＫＶ《     

30%TBP-煤油/HNO3体系在折流板脉冲萃取柱中的水力学性能

在Φ100mm折流板脉冲萃取柱中实验考察了30％TBP-煤油1mol/LHNO3体系下的萃取柱操作参数（脉冲振幅、脉冲频率、流速和流比）、结构参数（板间距）对萃取柱水力学性能（液泛通量、液泛存留分数和正常操作时分散相存留分数）的影响。实验研究结果表明：液泛通量随脉冲强度的减小而增大，与流比和板间距无关，研究给出了液泛通量与脉冲强度间的关联式；操作参数和柱结构参数对液泛存留分数的影响均可忽略；正常操作时分散相存留分数与连续相的流速、流比成正比关系，而与脉冲频率无关，并随板间距和脉冲振幅的增大而增加。      

小盲区超声反射镜技术无损检测管-板爆炸焊缝的研究

本文介绍了宽频窄脉冲超声技术和小直径声反射镜注水式探头无损检测管-板爆炸焊的原理,探头结构设计以及用它对S.S.-钢,Ti-S.S.,Zr-S.S.等热交换器管-板爆炸焊结合质量进行无损检测的实验结果     

射线探测中的能量和时间性能（续一）

射线探测中的能量和时间性能（续一）石宗仁（中国原子能科学研究院，北京２７５信箱２０分箱，１０２４１３）３能量的半高宽（ＦＷＨＭ）一个单色的带电粒子在探测器内沉积能量，在多道分析器上的脉冲谱是高斯分布，它表示了单能带电粒子经探测器和电子学线路后，脉冲幅...     

快速电流脉冲发生器的设计

为调节合肥同步辐射光源（HLS）时间分辨站的同步光脉冲间隔,需要产生具有快速上升、下降沿的脉冲磁场,且脉冲宽度小、顶部平坦。本工作利用脉冲成形技术设计电流脉冲发生器,以产生这种快速电流脉冲,并给出了实验结果。     

MHz重复频率双脉冲高压实验研究

介绍了在小型电子直线感应加速器（Mini-LIA）平台上利用两套相同的单脉冲高压功率系统通过脉冲汇流装置获得MHz重复频率双脉冲高压的实验结果。实验结果表明双脉冲高压间隔百纳秒至微秒可调,验证了通过汇流装置可获得百纳秒间隔多脉冲高压。     

低锡Zr—4包壳管电子束焊接时发生的合金元素蒸发现象

采用电子探针的波谱分析方法,对国产低锡Ｚｒ－４包壳管的环焊缝试样进行表面成份分析。分析结果表明,从焊缝的外边到内边缘,Ｓｎ,Ｃｒ,Ｆｅ元素的化学成份在统计上呈增大趋势,腐蚀后出现了白色产物的试样表层,其Ｓｎ,Ｃｒ,Ｆｅ元素含量相当程度地降低。这一事实表明,国产低锡Ｚｒ－４包壳管采用电子束焊接时,在一定的焊接规范环焊缝的合金元素存在严重蒸发现象,特别是合金中锡元素的蒸发使其锡元素含量低于０．５％,导     

AFA 3G燃料棒下端塞电子束焊产生气胀的分析

宜宾核燃料元件厂在AFA 3G燃料棒首次产品合格性鉴定中发现，大批下端环缝焊产生了气胀的焊接缺陷。本文分析了产生气胀缺陷的原因，并介绍了针对其原因进行的各种试验。结果表明，改变焊接参数，即提高焊接速度和适当控制电子束流强度，是解决燃料棒焊接气胀缺陷的最好途径。     

密封放射源焊接自控氩弧焊机及其焊接工艺研究

根据放射源密封焊接的特殊要求,对焊接设备进行了改进,增设了一些特殊线路,组装成专用的自控焊机。本文对焊接过程的各种影响因素,作了详细论述,并制定了较为适用的焊接工艺。     

电磁爆炸压接焊工艺研究

电磁爆炸压接焊,是一种新型的焊接方法。本文介绍了此种焊接新技术的工作原理、试验装置概况、压接工艺及检测方法等。与此同时,分析讨论了影响电磁爆炸压接焊的各种因素。对电磁爆炸压接焊的优越性和发展前景也作了一定的描述。     

Remove Welding Residual Stress for CFETR Vacuum Vessel by Trailing Ultrasonic Impact Treatment

The China fusion engineering test reactor (CFETR) vacuum vessel is welded by narrow gap TIG (NG-TIG) welding, and the welding residual stress of the CFETR vacuum vessel can be redistributed by trailing welding ultrasonic impact treatment. In order to investigate the feasibility of the residual stress removing scheme, and to obtain the optimal trailing ultrasonic impact treatment technological parameters in the process of removing welding residual stress, a welding model that similar to vacuum vessel welding seam is established by using ABAQUS software, a NG-TIG welding heat source subroutine which is written in FORTRAN language used to simulate NG-TIG welding. According to the welding simulation results, a trailing welding ultrasonic impact treatment model is established, and the effects of the impact pin number, the impact method, the impact pin diameter and the impact frequency on welding residual stress are studied. The results show that the longitudinal residual stress in welding seam and its adjacent area and the lateral residual stress in the whole region have been obviously decreased by different trailing welding ultrasonic impact processes, and have made the tensile stress in the welding seam and its adjacent area has been changed into compressive stress, which can provide theoretical guidance and reference for actual production.     

Design and Analysis of the Laser Robotic Welding System for ITER Correction Coil Case

ITER correction coil (CC) cases have characteristics of small cross section, large dimensions, and complex structure. The cases are made of heavy thick (20 mm), high strength and high toughness 316LN austenitic stainless steel. The laser welding is used for the case closure welding, due to its low heat input and deformation. According to the structural size and feature of the two types of cases, a set of laser welding workstation for the ITER CC case closure welding is designed. A slip plate module for the welding robot is designed to increase its workspace. According to the result of the movement simulation of the welding robots, the workstation is successful to cover all weld seams on the cases. Also, the welding platform and fixtures (includes the special welding tilter of the SCC) of the BTCC case and the SCC cases are designed. To verify the design structural feasibility of the welding tilter of SCC, the structural analysis for the rotating process has been formed in detail by using ANSYS. The simulating results show that the stress of the welding tilter can meet both static and fatigue criteria, and thus the basic structure is valid.     

Welding consumables for nuclear power plants

In nuclear power plants, submerged arc welding and covered arc welding have long been employed especially for main weld seams, including the core region of RPV.This paper investigates the mechanical properties of several welding consumables we have developed for industrial plants — that is, welding consumables which lower the phosphorus and copper content of the welded metal, those for plates possessing particularly high tensile strength and those for the narrow gap welding method.Recent data derived from irradiation embrittlement tests show that these welded metals using a non-copper coating are highly effective in minimizing shifts in the transition curve.Welding consumables for A533B C1.2, A543 C1.1 or A508 C1.4 steels have a higher tensile strength than those for A533B C1.1 or A508 C1.3.We have developed submerged arc and covered arc welding consumables to be used with these kinds of steels, and it was confirmed that these consumables possess excellent tensile strength and notch toughness.Our tests also confirmed that the narrow gap SAW and MIG welds are more efficient than the conventional ones. Moreover, the mechanical properties of the welded metals are also excellent.     

Numerical simulation of residual stresses induced by laser beam welding in a SUS316 stainless steel pipe with considering initial residual stress influences

With the development of computer hardware and software, numerical simulation technology has been widely used to predict welding temperature field, residual stresses and distortion. However, till now the influences of initial stresses induced by the manufacturing process before welding on the welding-induced residual stresses are rarely investigated experimentally and numerically. In the present work, we have developed a computational approach based on thermal elastic plastic FEM to clarify how the initial stresses due to heat treatment affect the welding-induced residual stresses in an austenitic stainless steel pipe. A heat treatment process, which is similar to solution heat treatment, is employed to produce initial stresses in the pipe before welding. After the heat treatment, the laser beam welding is used to perform a girth weld in the middle of the pipe. Through comparing the residual stress distributions after heat treatment and laser beam welding, we have investigated the influence of the initial residual stresses on the welding-induced residual stresses. The numerical results suggest that the initial residual stresses prior to welding have significant effects on the residual stresses after welding in the pipe model.     

Elucidation of Metallic Plume and Spatter Characteristics Based on SVM During High-Power Disk Laser Welding

During deep penetration laser welding,there exist plume(weak plasma) and spatters,which are the results of weld material ejection due to strong laser heating.The characteristics of plume and spatters are related to welding stability and quality.Characteristics of metallic plume and spatters were investigated during high-power disk laser bead-on-plate welding of Type 304 austenitic stainless steel plates at a continuous wave laser power of 10 kW.An ultraviolet and visible sensitive high-speed camera was used to capture the metallic plume and spatter images.Plume area,laser beam path through the plume,swing angle,distance between laser beam focus and plume image centroid,abscissa of plume centroid and spatter numbers are defined as eigenvalues,and the weld bead width was used as a characteristic parameter that reflected welding stability.Welding status was distinguished by SVM(support vector machine) after data normalization and characteristic analysis.Also,PCA(principal components analysis) feature extraction was used to reduce the dimensions of feature space,and PSO(particle swarm optimization) was used to optimize the parameters of SVM.Finally a classification model based on SVM was established to estimate the weld bead width and welding stability.Experimental results show that the established algorithm based on SVM could effectively distinguish the variation of weld bead width,thus providing an experimental example of monitoring high-power disk laser welding quality.