Academic literature on the topic 'Failed cladding'
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Journal articles on the topic "Failed cladding"
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Liu, Jinxia, Chao Ma, Luda Yu, Yu Wang, and Zhiyuan Jiao. "Remanufacturing of nodular cast iron crankshaft with plasma cladding." Advances in Mechanical Engineering 10, no. 6 (2018): 168781401877985. http://dx.doi.org/10.1177/1687814018779852.
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Remanufacturing technology has a wide range of applications in the repair of scrapped parts with a certain remaining service life. In this work, a scrapped crankshaft fabricated from nodular cast iron that had failed from working surface wear was remanufactured via a plasma cladding process. Taking into account the wear amount on the working surface and the characteristics of nodular cast iron, in this article, cladding layer parameters were designed and two types cladding powders, Fe-based and Ni-based, were prepared, respectively, to perform the cladding experiment. After examining different process parameters, relatively smooth cladding layers were obtained using four powders. The cladding experiment results showed that the powder No. 3 exhibited superior qualities when combined with proper processing parameters. When applying powder No. 3 to the main journal of crankshaft, a higher quality of cladding layer was achieved.
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Zu, Haiying, Yongpeng Liu, Sihui Chen, et al. "Forming Process Prediction Model and Application of Laser Cladding for Remanufactured Screw Pump Rotors." Materials 18, no. 7 (2025): 1673. https://doi.org/10.3390/ma18071673.
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In order to achieve high-quality repair of complex curved parts, a remanufacturing process method utilizing laser cladding and reverse engineering technology is proposed to be implemented by robots. This study focuses on the oscillating helical surface of a screw pump rotor. A single-pass laser cladding test is conducted using Response Surface Methodology (RSM) to construct a predictive model and identify optimal process parameters. The model’s accuracy is validated through analysis of variance (ANOVA) and index verification, while the optimal lap rate is determined through multi-pass laser cladding testing. Using reverse engineering technology, the generation of laser cladding paths for complex surfaces is explored, and the trajectory planning for the laser cladding robot is carried out. Simulations and experiments of robotic laser cladding on complex surfaces are performed, with the optimal process parameters guiding both the experiment and simulation. The optimum single-pass cladding layer, with a lap rate of 25.6%, is achieved when the laser power is 2217 W, the powder feed rate is 2.86 r/min, and the scanning speed is 400 mm/min. The study successfully plans the path for laser cladding on complex curved parts, verifying its feasibility and effectiveness, verifying that there is good metallurgical bonding between the cladding layer and the substrate, and helping to select the appropriate process parameters that are consistent with the requirements of a particular application, thus providing valuable guidance for the remanufacture of failed metal parts.
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Tong, Xin, Ming Jiang Dai, and Min Liu. "Laser Cladding of Iron-Based Self-Fluxing Alloy and its Application in Remanufacturing of Die-Casting Plunger." Advanced Materials Research 538-541 (June 2012): 1843–46. http://dx.doi.org/10.4028/www.scientific.net/amr.538-541.1843.
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Die-casting plunger often fails due to serious wear on its cylindrical surface. The scrap of plunger used in large die-casting machine results in waste of materials and energy sources, and it is also against environmental protection. Therefore, the laser remanufacturing of die-casting plunger was studied in this paper. Both of the size and the performance of plungers were repaired by laser cladding surface modification using an iron-based self-fluxing alloy. The interface between original failed plunger and laser cladding layer showed a good metallurgical bond. The average thickness of laser cladding layer was 0.845 mm, and the average micro-hardness reached to 750 HV upwards. Microstructure in laser cladding layer was composed by the dendrite primary phase and the ledeburite organization. Iron (Fe), Chromium (Cr) and Molybdenum (Mo) elements were the main chemical compositions measured in laser cladding layer. The service life of laser remanufacturing plunger was nearly the same as the life of new plunger. However, its remanufacturing cost was only 50% of the new plunger’s. The laser remanufacturing technique is worth for extending and applying due to high cost performance.
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Wang, Jong Rong, Hao Tzu Lin, Wan Yun Li, Shao Wen Chen, and Chun Kuan Shih. "Application of TRACE and FRAPTRAN in the Spent Fuel Pool of Chinshan Nuclear Power Plant." Applied Mechanics and Materials 479-480 (December 2013): 543–47. http://dx.doi.org/10.4028/www.scientific.net/amm.479-480.543.
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In the nuclear power plant (NPP) safety, the safety analysis of the NPP is very important work. In Fukushima NPP event, due to the earthquake and tsunami, the cooling system of the spent fuel pool failed and the safety issue of the spent fuel pool generated. In this study, the safety analysis of the Chinshan NPP spent fuel pool was performed by using TRACE and FRAPTRAN, which also assumed the cooling system of the spent fuel pool failed. There are two cases considered in this study. Case 1 is the no fire water injection in the spent fuel pool. Case 2 is the fire water injection while the water level of the spent fuel pool uncover the length of fuel rods over 1/3 full length. The analysis results of the case 1 show that the failure of cladding occurs in about 3.6 day. However, the results of case 2 indicate that the integrity of cladding is kept after the fire water injection.
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Lin, Jia Yi, Wei Hua Cui, Bin Han, Hui Wang, and Xi Hao Liu. "Research on Additive Manufacturing Technology in the Field of Mold Repair." Materials Science Forum 990 (May 2020): 61–66. http://dx.doi.org/10.4028/www.scientific.net/msf.990.61.
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With the rapid development of modern industry, mold as a basic hardware facility has become one of the important factors affecting the development of modern industry. The surface quality and working reliability of the mold have a direct impact on the quality of the part. Faced with a large number of failed molds in industrial production, fast and reliable mold repair technology can realize mold reuse under the premise of ensuring mold performance. It effectively shortens the construction period, saves costs and reduces mold waste. The article outlines the characteristics of wire and arc additive manufacturing technology, selective electron beam melting technology and laser cladding technology in additive manufacturing technology. The application characteristics of three additive manufacturing technologies in mold repair are analyzed. The application prospect of laser cladding technology in mold repair is pointed out. In view of the improved work reliability, the direction of laser cladding technology in the field of mold repair can be prospected.
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Dragunova, Anastasiya V., Mikhail S. Morkin, and Vladimir V. Perevezentsev. "Features of methods for monitoring the fuel cladding tightness in lead-cooled fast breeder reactors." Nuclear Energy and Technology 7, no. (4) (2021): 319–25. https://doi.org/10.3897/nucet.7.78372.
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To timely detect failed fuel elements, a reactor plant should be equipped with a fuel cladding tightness monitoring system (FCTMS). In reactors using a heavy liquid-metal coolant (HLMC), the most efficient way to monitor the fuel cladding tightness is by detecting gaseous fission products (GFP). The article describes the basic principles of constructing a FCTMS in liquid-metal-cooled reactors based on the detection of fission products and delayed neutrons. It is noted that in a reactor plant using a HLMC the fuel cladding tightness is the most efficiently monitored by detecting GFPs. The authors analyze various aspects of the behavior of fission products in a liquid-metal-cooled reactor, such as the movement of GFPs in dissolved and bubble form along the circuit, the sorption of volatile FPs in the lead coolant (LC) and on the surfaces of structural elements, degassing of the GFPs dissolved in the LC, and filtration of cover gas from aerosol particles of different nature. In addition, a general description is given of the conditions for the transfer of GFPs in a LC environment of the reactor being developed. Finally, a mathematical model is presented that makes it possible to determine the calculated activity of reference radionuclides in each reactor unit at any time after the fuel element tightness failure. Based on this model, methods for monitoring the fuel cladding tightness by the gas activity in the gas volumes of the reactor plant will be proposed.
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Zhao, Changlong, Chen Ma, Junbao Yang, et al. "Numerical Simulation Study of Multi-Field Coupling for Laser Cladding of Shaft Parts." Micromachines 14, no. 2 (2023): 493. http://dx.doi.org/10.3390/mi14020493.
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Since shaft parts operate under harsh environments for a long time, many critical parts suffer from corrosion, wear and other problems, leading to part failure and inability to continue in service. It is imperative to repair failed parts and increase their service life. An orthogonal experimental scheme is designed to numerically simulate the process of laser cladding of Inconel 718 alloy powder on 4140 alloy structural steel based on the ANSYS simulation platform, derive the relationship equation of cladding layer thickness according to the heat balance principle, establish a finite element model, couple three modules of temperature field, stress field and fluid field, and analyze different modules to realize the monitoring of different processes of laser cladding. The optimal cladding parameters were laser power 1000 W, scanning speed 15 rad/s, spot radius 1.5 mm, thermal stress maximum value of 696 Mpa, residual stress minimum value of 281 Mpa, and the degree of influence of three factors on thermal stress maximum value: laser power > spot radius > scanning speed. The pool in the melting process appears to melt the “sharp corner” phenomenon, the internal shows a double vortex effect, with a maximum flow rate of 0.02 m/s. The solidification process shows a different shape at each stage due to the different driving forces. In this paper, multi-field-coupled numerical simulations of the laser cladding process were performed to obtain optimal cladding parameters with low residual stresses in the clad layer. The melt pool grows and expands gradually during melting, but the laser loading time is limited, and the size and shape of the melt pool are eventually fixed, and there is a vortex flowing from the center to both sides of the cross-section inside the melt pool, forming a double vortex effect. The solidification is divided into four stages to complete the transformation of the liquid phase of the melt pool to the solid phase, and the cladding layer is formed. The multi-field-coupled numerical simulation technique is used to analyze the temperature, stress and fluid fields to provide a theoretical basis for the residual stress and surface quality of the clad layer for subsequent laser cladding experiments.
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Dragunova, Anastasiya V., Mikhail S. Morkin, and Vladimir V. Perevezentsev. "Features of methods for monitoring the fuel cladding tightness in lead-cooled fast breeder reactors." Nuclear Energy and Technology 7, no. 4 (2021): 319–25. http://dx.doi.org/10.3897/nucet.7.78372.
Full textAbstract:
To timely detect failed fuel elements, a reactor plant should be equipped with a fuel cladding tightness monitoring system (FCTMS). In reactors using a heavy liquid-metal coolant (HLMC), the most efficient way to monitor the fuel cladding tightness is by detecting gaseous fission products (GFP). The article describes the basic principles of constructing a FCTMS in liquid-metal-cooled reactors based on the detection of fission products and delayed neutrons. It is noted that in a reactor plant using a HLMC the fuel cladding tightness is the most efficiently monitored by detecting GFPs. The authors analyze various aspects of the behavior of fission products in a liquid-metal-cooled reactor, such as the movement of GFPs in dissolved and bubble form along the circuit, the sorption of volatile FPs in the lead coolant (LC) and on the surfaces of structural elements, degassing of the GFPs dissolved in the LC, and filtration of cover gas from aerosol particles of different nature. In addition, a general description is given of the conditions for the transfer of GFPs in a LC environment of the reactor being developed. Finally, a mathematical model is presented that makes it possible to determine the calculated activity of reference radionuclides in each reactor unit at any time after the fuel element tightness failure. Based on this model, methods for monitoring the fuel cladding tightness by the gas activity in the gas volumes of the reactor plant will be proposed.
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YANAGISAWA, Kazuaki, and Tore JOHNSEN. "In-Pile Eddy Current Test on PWR Fuel Rod Failed by Pellet-Cladding Interaction." Journal of Nuclear Science and Technology 23, no. 8 (1986): 752–55. http://dx.doi.org/10.1080/18811248.1986.9735049.
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Xiao, Xiang, Guo Zheng Zhou, Ke Qing Wang, Feng Xi, and Kun Zeng. "Study on In-Service Inspection of Nuclear Fuel Assembly Failure Using Ultrasonic Plate Wave." Sensors 22, no. 19 (2022): 7606. http://dx.doi.org/10.3390/s22197606.
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As protection for nuclear power plants is quite necessary, the nuclear fuel is sealed in zirconium alloy thin wall cladding. During service, fuel rods might be damaged caused by wall-thickness thinning, cladding corrosion and cracking, etc. This will cause the coolant to enter into the fuel rod, which may lead to the failure of the fuel assembly. However, current diagnostic methods have limitations due to the special structure of the fuel assembly and the underwater and radioactive environment. In this paper, a novel inspection method is proposed to recognize the failure of a fuel rod. The fuel rod failure can be detected based on the presence or absence of coolant inside the fuel rod by using an ultrasonic plate wave. The inspection model and process algorithm are proposed for in-service inspection. The relationship between signal and scanning position is established and analyzed. Both ultrasound field simulation and experiment have been carried out for validation. The corresponding results illustrate that the failed nuclear fuel rod of the whole fuel assembly (including the internal rods) can be effectively detected without the influence of the near-field region by using the proposed method.
Dissertations / Theses on the topic "Failed cladding"
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Faugeron, Mickael. "Diode laser 1.5 micron de puissance et faible bruit pour l’optique hyperfréquence." Thesis, Supélec, 2012. http://www.theses.fr/2012SUPL0018/document.
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Cette thèse porte sur la conception, la réalisation et la caractérisation de diodes lasers de puissance, faible bruit à 1.5 µm sur InP pour des applications d’optique hyperfréquence, notamment pour des liaisons optiques analogiques de grande dynamique pour les systèmes radar. La première partie du travail a consisté à modéliser et concevoir des structures laser DFB ayant de faibles pertes internes. Ces structures, appelées lasers à semelle, incorporent une couche épaisse de matériaux entre la zone active et le substrat pour agrandir et délocaliser le mode propre optique des zones dopées p. La complexité de la conception résidait dans le bon compromis à trouver entre les performances statiques et dynamiques. Nous avons réalisé des diodes-lasers DFB avec une puissance > 150 mW, un rendement de 0.4 W/A, un niveau de bruit de 160 dB/Hz et une bande passante de modulation à 3 dB de 7.5 GHz. Les composants ont ensuite été caractérisés puis évalués dans des liaisons analogiques. Nous avons démontré des performances de gain de liaison, de dynamique et de point de compression à l’état de l’art mondial. En bande L (1-2 GHz) par exemple, nous avons montré des liaisons avec 0.5 dB de gain, un point de compression de 21 dBm et une dynamique (SFDR) de 122 dB.Hz2/3.En utilisant la même méthodologie de conception, la dernière partie du travail de thèse a été consacrée à la réalisation et à la caractérisation de lasers de puissance à verrouillage de modes pour la génération de train d’impulsions ultra-courts et la génération de peignes de fréquences. Ces structures présentent de très faibles largeurs de raie RF (550 Hz) et de très fortes puissances optiques (> 18 W en puissance crête)<br>This work focuses on the design, realization and characterization of high power, low noise 1.5 µm diode lasers for microwave applications and more particularly for high dynamic optical analog link for radar systems. The first part of this study deals with modeling and design of low internal losses DFB laser structures. These specific structures are called slab-coupled optical waveguide lasers, and are composed of a thick layer between the active layer and the substrate. The aim of this waveguide is to enlarge the optical eigenmode and to move the optical mode away from p-doped layers. The main difficulty was to find the good trade-off between laser static performances (optical power, efficiency) and dynamic performances (RIN and modulation bandwidth). We have succeeded in developing high efficiency (0.4 W/A), low noise (RIN ≈ 160 dB/Hz) DFB lasers with more than 150 mW and a 3 dB modulation bandwidth up to 7.5 GHz. We have then characterized our components on wide band and narrow band analog links. We have demonstrated state of the art gain links, dynamic and 1 dB compression power. In the L band (1-2 GHz) for example, we have obtained an optical link with a gain of 0.5 dB, a compression power of 21 dBm and a dynamic (SFDR) of 122 dB.Hz2/3.Finally we have applied the methodology and the design of slab-coupled optical waveguide structures to develop high power mode-locked lasers for ultra-short pulses generation and for optical and electrical comb generation. We have demonstrated narrow RF linewidth (550 Hz) lasers with very high power (continuous power > 400 mW and peak power > 18 W)
Book chapters on the topic "Failed cladding"
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Onder, E. Nihan. "Fuel Failure Mechanisms and Fuel Failures." In Fundamentals of Nuclear Fuel. ASME, 2023. http://dx.doi.org/10.1115/1.887158_ch8.
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The term “fuel element failure” is used to indicate that the cladding is breached and the activity in the coolant can be detectable. The most important indicators to be measured for failed fuel elements include: i) iodine-131 in the primary coolant, ii) the sum of the activity of iodine isotopes, iii) radioactive noble gases, iv) uranium concentration in the primary coolant.
Conference papers on the topic "Failed cladding"
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Behnamian, Yashar, Duane Serate, Simon Yuen, et al. "A Case Study of External Cracking in Steam Piping under Mineral Wool Insulation." In CONFERENCE 2025. AMPP, 2025. https://doi.org/10.5006/c2025-00311.
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In recent years, cracking has been observed in carbon steel piping systems operating at temperatures above 70°C. These systems, equipped with mineral wool insulation and aluminum cladding, experienced cracking and failures under normal operating pressures and temperatures. Leachates from wet mineral wool insulation are suspected of causing external stress corrosion cracking (SCC) in these scenarios. A failure in a carbon steel steam condensate return pipe occurred at 50 PSI(g) and 330°F. Gaps in the insulation cladding allowed moisture to accumulate, which led to external stress corrosion cracking, particularly at the underside of the pipe where moisture collects. Material samples taken from the failed pipe showed intergranular cracking and grain elongation at the base of the cracks. This paper summarizes the findings of the investigation into the steam condensate piping failure, aiming to raise industry awareness and promote the safe operation of similar systems.
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Tinnea, Ryan, and Bruce Ostbo. "Evaluating the Corrosion Protection of a Nuclear Submarine Drydock." In CORROSION 2008. NACE International, 2008. https://doi.org/10.5006/c2008-08224.
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Abstract The Delta Pier, located at Naval Submarine Base Bangor at Bangor, Washington, has served as the West Coast dry dock for the US Navy’s Trident submarines since its completion in 1979. A flame-sprayed thermoplastic coating was applied to the sheet piles of the pier in 2000 and that coating system quickly failed. In January of 2007, the sheet piles of Delta Pier were inspected for corrosion damage. In concert with the inspection, the Navy requested that a replacement coating system be recommended. Many of the sheet piles on Delta Pier are located behind a section of closely spaced concrete piles that support concrete piers. The proximity of the concrete piles so severely limits construction access that traditional coating systems, such as high performance organic coating systems or thermal spray aluminum with a sealer may be economically infeasible. This paper discusses several rehabilitation strategies, the construction restraints, and how these divergent factors were resolved to allow clear recommendations to be made. Additional strategies include covering the sheet pile tidal and splash zone areas with cast-in-place concrete or cladding with a copper nickel alloy.
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Yin, Shengjun (Sean), B. Richard Bass, Wallace J. McAfee, and Paul T. Williams. "Experimental Program for Investigating the Influence of Cladding Defects on Burst Pressure." In ASME 2006 Pressure Vessels and Piping/ICPVT-11 Conference. ASMEDC, 2006. http://dx.doi.org/10.1115/pvp2006-icpvt-11-93272.
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An experimental program was conducted by the Heavy-Section Steel Technology Program at the Oak Ridge National Laboratory (ORNL) to evaluate the structural significance of defects found in the unbacked cladding of the Davis-Besse vessel head. ORNL conducted total 13 clad burst tests with unflawed/flawed specimens. Failure pressure data from those tests indicated a high degree of repeatability for the tests performed in the clad burst program. Unflawed clad burst specimens failed around the full perimeter of the disk from plastic instability; an analytical model for plastic collapse was shown to adequately predict those results. The flawed specimens tested in the program failed by ductile tearing of the notch defect through the clad layer. Analytical interpretations that utilized 3-D finite element models of the clad burst specimens were performed for all tests. Fractographic studies were performed on failed defects in the flawed burst specimens to verify the ductile mode of failure. Comparisons of computed results from 3-D finite element models with measured gage displacement data (i.e., center-point deflection and CMOD) indicated reasonably good agreement up to the region of instability. For tests instrumented with the CMOD gage, good agreement between calculated and measured CMOD data up to the onset of instability implies that ductile tearing initiated near the maximum load and (with a small increase in load) rapidly progressed through the clad layer to produce failure of the specimen.
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Ozaltun, Hakan. "Evaluation of Interface Stresses and Cladding-Cladding Delamination Failures In U-Mo Fuel Plates." In 2021 28th International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/icone28-65840.
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Abstract Monolithic fuel is a candidate fuel form for the conversion of high-performance research reactors. This plate-type fuel consists of a high-density, U-Mo alloy-based fuel in a monolithic form that is sandwiched between zirconium diffusion barriers and encapsulated in an aluminum cladding. To qualify this fuel system, the program must demonstrate that the fuel meets the safety standards, has a predictable behavior, and performs well in a reactor. Although many plates have shown satisfactory thermo-mechanical performance in reactor, a small number of experimental plates exhibited failures, rendering performance of these plates unacceptable. Post-irradiation examinations of failed plates have revealed that various failures modes are present, including pillowing, blistering, buckling, warping, delamination, fracture, rupture, oxide spallation, etc. Previous studies have implied that such various operational and loading conditions could generate a complex stress-strain state, facilitating distinct failure modes that could impact the structural integrity. To understand such various failure modes, a comprehensive set of studies focusing on failure modes is being performed. As a part of these studies, this work studies the cladding-cladding separation failures that were observed in some of previous irradiation tests. To understand the root cause of cladding separation failures, selected plates from previous irradiation experiments were simulated under comparable operational conditions. Stress-strain state of the plates at the interface were examined. The results were comparatively evaluated to understand possible effects of stress state of the bond-line on delamination failures. This paper presents these findings, discusses such failure modes, and examines the influence of various factors on previously observed cladding delamination failures.
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Lyu, Weifeng, Runchun Guo, Wenwang Ran, Yaoyi Gao, and Jun Xiong. "Improvements on Fuel Failures Diagnosis Method for Pressurized Water Reactor Nuclear Power Plant Based on Radioactive Activities Inside the Waste Gas Treatment System." In 2022 29th International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/icone29-92996.
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Abstract The cladding of fuel elements in the core of a pressurized water reactor nuclear power plant (PWR) is the first barrier to the radioactive material in the reactor. Once the fuel cladding fails, the radioactive fission products or even fissile material in the fuel elements will be released into the primary coolant, thereby challenging the safe operation of the plant. Fuel cladding failures diagnosis is indispensable for PWR as fuel failure is not inevitable and the impact on nuclear safety is significant. Based on the continuous research on fission product generation and release mechanisms for decades, several fuel failure diagnosis methods for PWR have been established and specific nuclides have been selected as indicators of fuel failures. Recent research shows Kr-85 is a good indicator for the diagnosis of the number of failed fuel rods for its insensitivity to the fuel rod defect size and failed fuel burn-up, but it is hard to measure the activity of Kr-85 in the primary coolant due to the interference of other nuclides. However, the activity of Kr-85 inside the waste gas treatment system can be measured where the activity of other nuclides has been significantly reduced by decay. Hence, the fuel failure diagnosis method is improved based on Kr-85 activities inside the waste gas treatment system. The operating data of Chinese in-service nuclear power plants are used to validate the improved fuel failure diagnosis method, and the validation results show that the improved diagnosis method of fuel failures can accurately diagnose the fuel failure and has wider applicability.
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Fu, Pengtao, and Zhijun Li. "A Method to Evaluate Defect Size of Failed Fuel Rods in CGN 1000MWe PWRs." In 2022 29th International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/icone29-92788.
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Abstract Fuel cladding is the first barrier to confine the release of fission products to the environment during normal operation. Once the fuel rods defect, the fission product accumulated in the pellet-cladding gap of failed fuel rods will release into the primary loop and lead to high activity levels in a pressurized water reactor. It is necessary to determine the status of fuel failure to avoid its degradation in the operation. This paper introduces the mechanism of the generation and release of fission products in fuel rods and the primary loops in a pressurized water reactor, and provides the theoretical method of the regression between release-to-birth R/B and decay constant λ of radio-iodine. It has been verified by one typical case of fuel failure in CGN 1000 MWe PWR, but the post-irradiation examinations in hot cell reveal that six defects exist in one failed rod and the actinides have an obvious release from the failed rods due to secondary hydriding. The actual status of defect size of failed rods is much more complicated than expected in most analysis codes and modelings and it is suggested to introduce some parameters, e.g. the equivalent defect size, to describe the status of fuel failure in future research. The related operation experience in CGN has also been presented to help to better understand the status of fuel failure in PWR units.
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Raju, Vijayashree, Rajan Babu Vinayagamoorthy, Parthasarathy Uppala, Sureshkumar Ramachandran, Raghupathy Sundararajan, and Chellapandi Perumal. "Design and Development of Failed Fuel Location Module for Prototype Fast Breeder Reactor." In 2014 22nd International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/icone22-30913.
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Prototype Fast Breeder Reactor (PFBR), India’s first commercial fast breeder reactor employing fast fission is a challenging project from technological point of view to meet the energy security of the country. PFBR is a sodium cooled fast reactor. There are 198 fuel sub assemblies with mixed oxide fuel in the reactor. The fuel is provided with a leak tight metal cladding for containment of the fission products. There are risks of sodium circuit contamination and the fission products blocking the coolant flow to the fuel sub assemblies in case of clad rupture and release of solid fission products into the coolant. Hence PFBR is equipped with an elaborate failed fuel detection and location system. Failed Fuel Location Module is one of the subsystems used to identify the sub-assembly having fuel pins with clad failure. This paper discusses about the conceptual design, design specifications, detailed design, manufacture, assembly and some of the results of functional testing of failed fuel location module of PFBR.
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Stuckert, J., M. Große, C. Rössger, M. Steinbrück, and M. Walter. "Influence of the Temperature History on Secondary Hydriding and Mechanical Properties of Zircaloy-4 Claddings: An Analysis of the QUENCH-LOCA Bundle Tests." In 2014 22nd International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/icone22-30792.
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Two out-of-pile bundle tests, QUENCH-L0 and QUENCH-L1, were performed recently at Karlsruhe Institute of Technology (KIT) in the framework of the QUENCH-LOCA program devoted to the investigation of the so-called secondary hydriding of the cladding. The overall objective of this bundle test series is the investigation of ballooning, burst and secondary hydrogen uptake of the cladding under representative design basis accident conditions as well as detailed post-test investigation of cladding mechanical properties to analyze the material behavior with respect to embrittlement. The program was started in 2010 with the QUENCH-L0 commissioning test using 21 electrically heated rods with as-received Zircaloy-4 claddings followed in 2012 by the QUENCH-L1 reference test using the same material. These two tests differ in 1) heat-up rate during the first transient and 2) presence of a cool-down phase before quenching. The maximum heating rate reached during QUENCH-L0 was only 2.5 K/s, whereas the transient phase of QUENCH-L1 was performed with the maximum rate of 7 K/s. The state of the QUENCH-L0 bundle was practically “frozen” immediately after the transient phase by fast injection of two-phase fluid. The reference test QUENCH-L1, was performed with a typical cooling phase after the transient phase. It provides data on Zircaloy-4 cladding embrittlement based on more prototypical temperature history. Post-test neutron radiography and tomography revealed formation of hydrogen bands around the oxidized inner cladding surface in vicinity of the burst openings for both tests. However, the concentration of hydrogen absorbed inside these bands was different for both tests: whereas the maximum hydrogen concentration for QUENCH-L0 reached 2560 wppm, the corresponding value for QUENCH-L1 was only 1690 wppm. Complementary model calculations confirm that the differences in hydrogen concentrations are mainly related to the differences in temperature sequences. Subsequent tensile tests with tube segments at room temperature revealed the dependence of the mechanical behaviour on hydrogen concentration: tubes with hydrogen contents above 1500 wppm were simultaneously double ruptured along the hydrogen bands, whereas tubes with hydrogen concentrations below 1500 wppm failed at the middle of burst openings.
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Kvaale, Per Egil, Tore Ha˚brekke, and Gisle Ro̸rvik. "Experience With Qualification and Use of Stainless Steels in Subsea Pipelines." In ASME 2004 23rd International Conference on Offshore Mechanics and Arctic Engineering. ASMEDC, 2004. http://dx.doi.org/10.1115/omae2004-51536.
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Use of stainless steels in subsea oil and gas production systems have been common through the development of remote controlled subsea oil and gas production systems. Stainless steels are mainly selected to minimize the corrosion due to unprocessed oil and gas and thereby simplifying the internal corrosion protection challenges. Different materials and principles have been implemented from cladding of Carbon Manganese steels to the use of solid stainless steels. For cladding Incoloy 825 or Inconel 625 is common, while the solid stainless steels have been duplex, superduplex or 13%Cr steels in pipes and pipe fittings. Experience from service has shown that these materials have limits in their use, and it is reported various cases where the stainless steels have failed. The present paper will deal with a few examples of failures and possible reasons for these failures.
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Carrilho, Leo A. "Stress Analysis of the Pressurized-Water Reactor Control Rod Under Operating Conditions." In 2020 International Conference on Nuclear Engineering collocated with the ASME 2020 Power Conference. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/icone2020-16872.
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Abstract This work aims to develop a finite element model of a PWR control rod at operating conditions for stress analysis of the rod cladding. The finite element model simulates a control rod exposed to high operating temperatures and pressure while portions of the rod are irradiated, resulting in accumulated fluence of neutrons by the rod materials. These high temperature and accumulated fluence induce thermal expansion and swelling of the rod materials, especially of the absorber, which may eventually interact with the rod cladding, generating stresses and strains in the wall of the cladding tube. Moreover, if the maximum stress or strain in the tube wall exceeds the design allowable limit, the absorber rod is considered failed. The author creates the control rod finite element model and apply the operating loads on two-dimensional axisymmetric elements to obtain displacements, temperatures, stresses, and strains. The model also includes contact surface elements to evaluate eventual mechanical interactions between absorber and cladding due to thermal expansion and swelling effects. This is a coupled nonlinear static analysis solution that includes thermal expansion effects to calculate temperature distribution and subsequent thermal strains in the absorber rod due to the heat generation rates and coolant temperature; swelling analysis to calculate absorber growth induced by irradiation; and creep analysis to calculate absorber stress relaxation under coolant pressure and temperature. The finite element model is capable of determining whether or not absorber-to-cladding gap closure will occur and if so, calculate maximum stress and strain in the rod cladding associated with mechanical interaction between the two components induced by the operating temperature and thermal fluence loads.