scholarly journals Fundamental Study on Underwater Cutting of 50 mm-Thick Stainless Steel Plates Using a Fiber Laser for Nuclear Decommissioning

2022 ◽  
Vol 12 (1) ◽  
pp. 495
Author(s):  
Kwan Kim ◽  
Moo-Keun Song ◽  
Su-Jin Lee ◽  
Dongsig Shin ◽  
Jeong Suh ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Laser Power ◽  
Laser Cutting ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Cutting Speed ◽  
Cutting Surface ◽  
Focal Position ◽  
Underwater Laser

With nuclear power plants worldwide approaching their design lifespans, plans for decommissioning nuclear power plants are increasing, and interest in decommissioning technology is growing. Laser cutting, which is suitable for high-speed cutting in underwater environments and is amenable to remote control and automation, has attracted considerable interest. In this study, the effects of laser cutting were analyzed with respect to relevant parameters to achieve high-quality underwater laser cutting for the decommissioning of nuclear power plants. The kerf width, drag line, and roughness of the specimens during the high-power laser cutting of 50 mm-thick stainless steel in an underwater environment were analyzed based on key parameters (focal position, laser power, and cutting speed) to determine the conditions for satisfactory cutting surface quality. The results indicated that underwater laser cutting with a speed of up to 130 mm/min was possible at a focal position of 30 mm and a laser power of 9 kW; however, the best-quality cutting surface was obtained at a cutting speed of 30 mm/min.

Underwater laser cutting of stainless steel up to 100 mm thick for dismantling application in nuclear power plants

2020 ◽  
Vol 147 ◽  
pp. 107655 ◽  
Author(s):  
Jae Sung Shin ◽  
Seong Yong Oh ◽  
Seungkyu Park ◽  
Hyunmin Park ◽  
Taek-Soo Kim ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Laser Cutting ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Underwater Laser

Investigation on Acoustic Emission Characteristics from Corrosion of Conventional Materials of Primary Pipe in Nuclear Power Plants

2014 ◽  
Vol 487 ◽  
pp. 54-57 ◽  
Author(s):  
Meng Yu Chai ◽  
Li Chan Li ◽  
Wen Jie Bai ◽  
Quan Duan
Keyword(s):  
Stainless Steel ◽  
Acoustic Emission ◽  
Pitting Corrosion ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
316L Stainless Steel ◽  
304 Stainless Steel ◽  
Emission Characteristics ◽  
Research Topics

304 stainless steel and 316L stainless steel are conventional materials of primary pipeline in nuclear power plants. The present work is to summarize the acoustic emission (AE) characteristics in the process of pitting corrosion of 304 stainless steel, intergranular corrosion of 316L stainless steel and weldments of 316L stainless steel. The work also discussed the current shortcomings and problems of research. At last we proposed the coming possible research topics and directions.

Effect of focal position on cut surface quality in laser cutting of 50-mm thick stainless steel

2021 ◽  
pp. 2140018
Author(s):  
Moo-Keun Song ◽  
Jong-Do Kim ◽  
Dong-Sig Shin ◽  
Su-Jin Lee ◽  
Dae-Won Cho
Keyword(s):  
Stainless Steel ◽  
Laser Beam ◽  
Laser Cutting ◽  
Nuclear Power ◽  
Surface Characteristics ◽  
Kerf Width ◽  
Power Structures ◽  
Thick Sample ◽  
Focal Position ◽  
Cut Surface

In this study, the parameters for underwater laser cutting of 50-mm thick stainless steel, which is typically used in nuclear power structures, are investigated. The focal position of laser beam significantly affects the cutting quality. In particular, in the cutting of the thick sample, change in the focal position determines the kerf width and the roughness of the cut surface. Moreover, the effects of the variation of kerf width and the cut surface characteristics on the focal position of the laser beam are investigated. As the focal position moved to the inside of the material, the upper kerf width increased, but the quality of the cut surface was improved.

scholarly journals Cutting Properties of Austenitic Stainless Steel by Using Laser Cutting Process without Assist Gas

2012 ◽  
Vol 2012 ◽  
pp. 1-8
Author(s):  
Hitoshi Ozaki ◽  
Yosuke Koike ◽  
Hiroshi Kawakami ◽  
Jippei Suzuki
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Molten Metal ◽  
Laser Power ◽  
Laser Cutting ◽  
Cutting Speed ◽  
Cutting Process ◽  
Metallic Materials ◽  
Bottom Side ◽  
Gas Nozzle

Recently, laser cutting is used in many industries. Generally, in laser cutting of metallic materials, suitable assist gas and its nozzle are needed to remove the molten metal. However, because of the gas nozzle should be set closer to the surface of a workpiece, existence of the nozzle seems to prevent laser cutting from being used flexible. Therefore, the new cutting process, Assist Gas Free laser cutting or AGF laser cutting, has been developed. In this process, the pressure at the bottom side of a workpiece is reduced by a vacuum pump, and the molten metal can be removed by the air flow caused by the pressure difference between both sides of the specimen. In this study, cutting properties of austenitic stainless steel by using AGF laser cutting with 2 kW CO2 laser were investigated. Laser power and cutting speed were varied in order to study the effect of these parameters on cutting properties. As a result, austenitic stainless steel could be cut with dross-free by AGF laser cutting. When laser power was 2.0 kW, cutting speed could be increased up to 100 mm/s, and kerf width at specimen surface was 0.28 mm.

Laser Cutting Quality of the Ceramic Slabs

2006 ◽  
Vol 505-507 ◽  
pp. 847-852 ◽  
Author(s):  
Xu Yue Wang ◽  
Wen Ji Xu ◽  
Ren Ke Kang ◽  
Yi De Liang
Keyword(s):  
Laser Power ◽  
Laser Cutting ◽  
Cutting Speed ◽  
Cutting Parameters ◽  
Incident Laser Power ◽  
Focal Position ◽  
Geometrical Features ◽  
The Relationship ◽  
Cutting System

An experimental analysis is presented which investigates the relationship between cutting parameters and the volume of material removal as well as its cutting quality on a Nd:YAG laser cutting system. The parameters that varied on two testing thickness during cutting include cutting speed, incident laser power and focal position in a continuous through cut. Various trends of the kerf geometrical features in terms of the varying process parameters are analyzed and shown to be reasonable. Discussions are also given on kerf geometry control in situations with cutting parameters. It shows that the effects of varying parameters such as cutting speed, laser power and focal position on cutting kerf width, surface roughness, and striation that have provided a deeper understanding of the laser machining.

High Quality Fiber Laser Cutting of Electronic Alumina Ceramics

2010 ◽  
Vol 154-155 ◽  
pp. 917-922 ◽  
Author(s):  
Xiao Chuan Chen ◽  
Ling Fei Ji ◽  
Yong Bao ◽  
Yi Jian Jiang
Keyword(s):  
Fiber Laser ◽  
Laser Power ◽  
Laser Cutting ◽  
Cutting Speed ◽  
Alumina Ceramics ◽  
High Quality ◽  
Spot Diameter ◽  
Cutting Surface ◽  
Power Threshold

In this paper, high quality cutting of 1 mm dense Al2O3 electronic ceramic processed by a fiber laser with spot diameter of 15 μm was reported. The narrow kerf with 30μm width was obtained with laser power of 100 W. 300 W is the laser power threshold of the kerf enlargement. Under higher laser power, the ceramics can be damage-free cut with higher cutting speed. Striation-free cutting could be achieved at 1000 W laser power with a cutting speed of 350 mm/s. The ratio of cutting speed to laser power for striation-free cutting was determined as 0.35. The black cutting surface was due to the mass tetragonal alumina induced by N2 as assist gas.

Current in-service inspections of austenitic stainless steel and dissimilar metal welds in light water nuclear power plants

1994 ◽  
Vol 151 (2-3) ◽  
pp. 539-550 ◽  
Author(s):  
Ludwig von Bernus ◽  
Werner Rathgeb ◽  
Rudi Schmid ◽  
Friedrich Mohr ◽  
Michael Kröning
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Light Water ◽  
Dissimilar Metal

scholarly journals Friction Stir Welding and Preliminary Characterization of Irradiated 304 Stainless Steel

2019 ◽  
Author(s):  
Wei Tang ◽  
Maxim Gussev ◽  
Zhili Feng ◽  
Brian Gibson ◽  
Roger Miller ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Friction Stir Welding ◽  
Base Metal ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Weld Zone ◽  
Fusion Welding ◽  
Friction Stir

Abstract The mitigation of helium induced cracking in the heat affected zone (HAZ), a transition metallurgical zone between the weld zone and base metal, during repair welding is a great challenge in nuclear industry. Successful traditional fusion welding repairs are limited to metals with a maximum of a couple of atomic parts per million (appm) helium, and structural materials helium levels in operating nuclear power plants are generally exceed a couple of appm after years of operations. Therefore, fusion welding is very limited in nuclear power plants structural materials repairing. Friction stir welding (FSW) is a solid-state joining technology that reduces the drivers (temperature and tensile residual stress) for helium-induced cracking. This paper will detail initial procedural development of FSW weld trials on irradiated 304L stainless steel (304L SS) coupons utilizing a unique welding facility located at one of Oak Ridge National Laboratory’s hot cell facilities. The successful early results of FSW of an irradiated 304L SS coupon containing high helium are discussed. Helium induced cracking was not observed by scanning electron microscopy in the friction stir weld zone and the metallurgical zones between the weld zone and base metal, i.e. thermal mechanical affected zone (TMAZ) and HAZ. Characterization of the weld, TMAZ and HAZ regions are detailed in this paper.

scholarly journals Parameters influencing the low-cycle fatigue life of materials in pressure water reactor nuclear power plants / Parametry ovlivòující únavové chování materiálù pro tlakovodní jaderné reaktory v režimu nízkocyklové únavy

2015 ◽  
Vol 59 (3) ◽  
pp. 91-98
Author(s):  
V. Šefl
Keyword(s):  
Stainless Steel ◽  
Fatigue Life ◽  
Carbon Steel ◽  
Austenitic Stainless Steel ◽  
Literature Review ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Low Cycle Fatigue ◽  
Cycle Fatigue

Abstract In this literature review we identify and quantify the parameters influencing the low-cycle fatigue life of materials commonly used in nuclear power plants. The parameters are divided into several groups and individually described. The main groups are material properties, mode of cycling and environment parameters. The groups are further divided by the material type - some parameters influence only certain kind of material, e.g. sulfur content may decreases fatigue life of carbon steel, but is not relevant for austenitic stainless steel; austenitic stainless steel is more sensitive to concentration of dissolved oxygen in the environment compared to the carbon steel. The combination of parameters i.e. conjoint action of several detrimental parameters is discussed. It is also noted that for certain parameters to decrease fatigue life, it is necessary for other parameter to reach certain threshold value. Two different approaches have been suggested in literature to describe this complex problem - the Fen factor and development of new design fatigue curves. The threshold values and examples of commonly used relationships for calculation of fatigue lives are included. This work is valuable because it provides the reader with long-term literature review with focus on real effect of environmental parameters on fatigue life of nuclear power plant materials.

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