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许多含有表面平面缺陷的金属结构都受到随机载荷的作用.以结构可靠度为基础探讨了随机载荷对结构安全评定的影响.通过统计结构所承受的载荷,得到随机载荷的统计参数(平均载荷、载荷标准差),并使用载荷的统计参数对实际载荷进行等效处理.通过蒙特卡罗方法计算结构的可靠度,研究一定可靠度下随机载荷的变异系数和分散性安全系数的关系.结果发现,不考虑载荷分散性的影响是偏于危险的.载荷分散性的影响可以分散性系数来衡量,使用分散性安全系数对载荷进行等效处理,最后采用处理后的等效载荷进行结构的安全评定. 相似文献
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固体发动机的缺陷主要有药柱内气孔、裂纹和多界面脱粘,这些缺陷在ICT检测生成的断层图像中,和整幅断层图像相比只占据少量像素,给缺陷分析带来困难.采用图像插值技术放大含有缺陷的局部断层图像,可获得更丰富的缺陷信息.文章将图像插值技术分为基于图像插值方法和基于对象插值方法两类,分别进行分析、比较,并给出含有典型缺陷的固体发动机断层局部图像放大4×4倍后的图像.经过对比,基于对象的插值方法效果明显优于基于图像的插值放大方法,但其计算量大、耗时多.在固体发动机断层缺陷图像放大分析中,今后研究重点应是简化现有的或提出新的基于对象的插值方法,保证插值精度基础上提高插值速度. 相似文献
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SWD-Ⅰ型涡流探伤仪及其配套设备包括:1.探伤仪主机;2.配套探头系列;3.探头插座;4.自动喷色标记系统。它运用涡流探伤原理,配用穿过式探头广泛,适用于核工业各工矿企业的生产流水线上对各种金属材料进行自动探伤。该套设备具有下述特点:(1)凡是金属丝材、管材、棒材均可用它来进行探伤;(2)被测材料直径从φ1~φ36mm,设计特殊探头可扩大到φ87以上,可对异型截面材料及板材探伤;(3)对不同直径的工件探伤时,只需更换探头,不必更换主机。操作简便,检测效率高;(4)机内配有多种显示缺陷的功能。特别是采用自动喷色标记器,可以直观、准确地将探出缺陷直接标记在工件上,便于分选使用;(5)本机体积小、重量轻、成本低、适用于生产规模的连续检测。 相似文献
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工业CT是一种有效的工件缺陷识别的方法,代表着无损检测技术的发展方向.首先概述工业CT技术在工件缺陷识别中的应用,并把其他和其他常用方法进行了简单比较;接着从工件缺陷识别的流程入手,对每个步骤都从处理思路和处理方法方面作了阐述;然后对一些在工件缺陷识别方面很有潜力的算法(Level set和Gabor小波)进行了介绍和分析;最后对工业CT在工件缺陷识别方面的应用前景进行了展望. 相似文献
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通过对常用无损检测技术的比较,结合岭澳核电站安全壳老化检测的工程实例研究雷达技术在混凝土无损检测中的应用效果,并针对实际问题,对雷达图像资料进行分析,研究了影响冒达成像的因素,以提高建筑物修复加固依据的科学性. 相似文献
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田湾核电站波动管的焊接过程中出现了超标缺陷。本文描述了北方监督站在2号机组波动管焊接及缺陷的处理过程中所进行的核安全监督。 相似文献
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《Fusion Engineering and Design》2014,89(7-8):1024-1028
Carbon fiber composite (CFC) monoblock divertor target is required for power handling in JT-60SA. Quality of the targets depends on a joining technology in manufacturing process. To inspect the quality of more than 900 target pieces, efficient non-destructive inspection is needed. An infrared thermography inspection (IR inspection), has been proposed by ITER and IRFM, where the quality between CFC and a cooling tube is examined by a use of transient thermal response at a rapid switch from hot to cold water flow. In JT-60SA divertor target, a screw tube will be employed to obtain high heat transfer efficiency with simple structure. Since the time response of the screw tube is much faster than that of smooth tube, it is required to confirm the feasibility of this IR inspection. Thus, the effect of joining defects on transient thermal response of the targets has been investigated experimentally by using the mock-up targets containing defects which are artificially made. It was found that the IR inspection can detect the defects. Moreover, screening criteria of IR inspection for acceptable monoblock target is discussed. 相似文献
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The reliability of an eddy current testing (ECT) inspection system depends upon the inspection technique and quality of analyst. In evaluating the integrity of a steam generator (SG) tube, degradation detection and sizing accuracy are considered performance measures of the nondestructive evaluation (NDE) system. A probability of detection (POD) model serves as a functional measure of the ability of an NDE system to detect degradation. It is one of the inputs in the operational assessment, and it is used to estimate the degradation during service via ECT of the SG tube. In this study, the POD functions of the inspection technique and analyst were obtained to quantitatively analyze the ECT bobbin probe for axial outside diameter stress corrosion cracks in SG tubes. This should serve to evaluate the integrity of the SG tubes. The depth and amplitude of defects were used as parameters of the POD model. Hit (detection) and miss (no detection) binary data obtained from destructive and nondestructive inspection of cracked tubes were also used. 相似文献
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As a remedy to the practical problem of defects in fuel alignment pins made of Inconel X750, an inspection technique has been developed which fully meets the requirements of detecting defects. The newly used fuel alignment pins made of austenite are easy to test and therefore satisfy the necessity of further inspections.For the fuel alignment pins of the upper core structure a safe and fast inspection technique was made available. The inspection sensitivity is high and it is possible to give quantitative directions concerning defect orientation and depth. After the required inspections had been concluded in 1989, a total of 18 inspections were carried out in various national and international nuclear power plants in the following years. During this time more than 6000 fuel alignment pines were examined.For the fuel alignment pins the inspection technique provided could increase the understanding of the defect process. This technique contributed to the development of an adaptive and economical repair strategy. 相似文献
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A case study on detection and sizing of defects in steam generator tubes using eddy current testing 总被引:1,自引:0,他引:1
Eddy current testing (ECT) method is widely used to detect various types of defects occurring in nuclear steam generator tubes. Therefore, the reliability of its detection and sizing accuracy for defects should be validated. For this purpose, two tubes with defect signals were pulled from an operating steam generator and destructively examined. The defect type was a circumferential crack for one tube and an intergranular attack (IGA) for the other tube. The plus point coil probe showed a better capability to detect and size both a circumferential crack and a volumetric IGA than pancake and bobbin coil probe. The destructive results are correlated with the ECT results obtained during the in-service inspection. 相似文献
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Bengt Malmberg 《Nuclear Engineering and Design》1991,131(3)
It is essential to know why an inspection is required and what type and size of flaw is expected to be detected. A very basic knowledge it seems. However, many national codes and standards are not fully adequate in this respect. The selection of inspection items as well as the acceptance criteria of detected defects are often defined in very general terms. Degradation processes are very little reflected in the standard ISI selection scope which creates demands on additional inspection programs. The swedish authority, the Swedish Nuclear Power Inspectorate (SKI) have issued a new code for in-service inspections which deals with this issues. This paper describes the basics of the new code, the implementation and the experience gained from in plant inspections at Barsebäck Nuclear Power plant. 相似文献
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The in-service inspection of nuclear facilities should make it possible to detect all flaws capable of deterioration. The size of a flaw is not normally characteristic of its seriousness: a large, stable defect which is not developing is of no importance for the safety of the facility whereas a small but developing defect may be dangerous and hence of importance for safety. It is essential to detect all defects, so that any development they may be undergoing can be assessed, and to use, for that purpose, a technique with a maximum detection probability; but the main thing is to characterize all developing defects. For the in-service inspection of pressurized-water reactor vessels the “Commissariat à l'Energie Atomique” has conducted studies on inspection methods with a view to ensuring first the best possible detection and secondly the best possible characterization of flaws. Since 1973 many publications have appeared on the subject and this paper will only recall the essentials giving particular attention however to the characterization of defects, which is the principal purpose of the studies currently being conducted. 相似文献
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Jarmo Raussi 《Nuclear Engineering and Design》1980,60(3):395-399
The weld defects appearing in the pipes of the main steam system in a BWR power plant were studied. The effect of inspection rejection and repair on the imperfection size distribution was analysed. The size distributions before and after the inspection rejection as well as after the repair procedure were of the form a + b/x2, where x is the imperfection size and a and b are coefficients. The portion of the rejected defects had the size dependence near to the form of the cumulative Gaussian function. The effect of repair on the initial size distribution had the form of the cumulative Poisson distribution. 相似文献
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Shigeru Miyoshi Yoshinori Tanimoto Kiichiro Uyama Yuji Sano 《Nuclear Engineering and Design》1987,102(3)
The X-ray computed CT scanner, capable of producing sharp tomograms, was expected to become a practical and revolutional means in nondestructive inspection in the industrial field.In Japan, the development of the Linac X-ray CT scanner is under way for the inspection of SCC in welds of a nuclear power plant. For development of the Linac-CT, the preliminary experiments for the inspection of SCC artificial defects were performed using a 420 kVp industrial X-ray CT scanner (TOSCANER 4200) which had been developed by Toshiba Corporation. This paper includes the background of this program and the summary of preliminary experiments for X-ray CT. 相似文献