Academic literature on the topic 'Ballooning accidents'
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Journal articles on the topic "Ballooning accidents"
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Kataria, Sant P., Narender Singh, Sanjay Kumar, Mamta ., and Vijaypal Khanagwal. "Spectrum of morbid anatomy of liver in autopsy cases." International Journal of Research in Medical Sciences 9, no. 7 (June 25, 2021): 2008. http://dx.doi.org/10.18203/2320-6012.ijrms20212524.
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Background: Purpose of autopsy is to learn the truth about the person’s health during and how the person died. Thus, autopsy study provides valuable information about the disease. The main aim of the study was to know the spectrum of morbid anatomical changes in liver autopsy.Methods: A prospective study was carried out on 100 liver specimens of autopsy cases comprising of 37 cases of roadside accidents, 17 of poisoning, 13 of burns, 10 of chronic illness, 7 each of hanging and head injury, 4 of myocardial infarction and 5 of death due to miscellaneous causes. Representative microsections of liver were evaluated for histopathological parameters like congestion, ballooning degeneration, hepatocellular necrosis, sinusoidal dilation, fatty change, bile stasis, fibrosis, lobular inflammation and portal inflammation.Results: Out of total 100 cases, 77 were males and 23 females. Male to female ratio was 3.34:1. Hepatomegaly was seen in 15% of cases. Chronic venous congestion was the main histopathological diagnosis seen in 61% of the cases followed by chronic hepatitis in 12%, normal liver histology in 9%, hepatic steatosis and cirrhosis in 6%, granulomatous hepatitis in 2%, and sinusoidal congestion, portal triaditis and secondary neoplasm in 1% each.Conclusions: Chronic venous congestion, chronic hepatitis, cirrhosis and hepatic steatosis were the common liver diseases identified. Autopsy study is useful to monitor the cause of death and to plan medical strategy. Histopathological examination of the liver is specialized learning tool to study the various diseases of liver which is a great value in improving the diagnosis.
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Lee, K. A. P. "A ballooning accident with multiple fatalities." Pathology 24 (1992): 14. http://dx.doi.org/10.1016/s0031-3025(16)35931-1.
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Schütte, Frank, Martin Ebstein, Markus Rottmann, and Joachim Thale. "Nearly asymptomatic left ventricular apical ballooning after a hit-and-run accident." International Journal of Cardiology 128, no. 3 (August 2008): 439–41. http://dx.doi.org/10.1016/j.ijcard.2007.06.042.
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Serrano, Ryan M., Marcus Schamberger, and John J. Parent. "Takotsubo cardiomyopathy secondary to non-accidental trauma presenting as an “unwitnessed” arrest." Cardiology in the Young 29, no. 3 (February 4, 2019): 442–44. http://dx.doi.org/10.1017/s1047951118002366.
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AbstractTakotsubo cardiomyopathy is characterised by akinesis and ballooning of the left ventricular apex during contraction of the otherwise normal base of the heart. We describe the case of a 7-month-old previously healthy female who presented with an unwitnessed cardiac arrest. Workup raised suspicion for non-accidental trauma. Despite progression to brain death, the severely decreased ventricular function and apical akinesis of the left ventricle improved within 40 hours of admission. This report will familiarise paediatricians with this rare cardiomyopathy and emphasise the importance of considering non-accidental trauma as an inciting event for patients with unwitnessed cardiac arrest found to have decreased ventricular function.
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Kim, Hyoung Tae, Se-Myong Chang, Young Woo Son, and Taegee Min. "Multiphysical Simulations for the IAEA/ISCP Benchmark Model on the Contact of Pressure Tube and Calandria Tube in the Moderator System of CANDU-6 PHWR." Science and Technology of Nuclear Installations 2018 (November 1, 2018): 1–8. http://dx.doi.org/10.1155/2018/3096862.
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The LOCA (loss of coolant accident) is a kind of severe accident in the operation of PHWR (pressurized heavy water reactor) as well as other nuclear facilities, and possible cause of LOCA can be counted on the ballooning of pressure tube (PT) contacted to the outer calandria tube (CT) in the moderator system of CANDU-6 reactors. In the paper, we simulated the 150-kW experimental facility proposed by IAEA/ISCP, modeling the transient creeping behavior of pressurized tube heated with thermal radiation between the gaps of two concentric pipes. The outer boundary is simplified with a switched model that depends on the local temperature. With a multiphysical model supported by a commercial code, COMSOL multiphysics, the unsteady phenomena are simulated with models concerning various kinds of mechanics such as thermodynamics, nonlinear structural dynamics, and two-phase boiling heat transfer models.
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Lewis, John M., and Charles B. Moore. "LeRoy Meisinger, Part II: Analysis of the Scientific Ballooning Accident of 2 June 1924." Bulletin of the American Meteorological Society 76, no. 2 (February 1995): 213–26. http://dx.doi.org/10.1175/1520-0477(1995)076<0213:lmpiao>2.0.co;2.
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Kim, Jinsu, Jeong Whan Yoon, Hyochan Kim, and Sung-Uk Lee. "Prediction of ballooning and burst for nuclear fuel cladding with anisotropic creep modeling during Loss of Coolant Accident (LOCA)." Nuclear Engineering and Technology 53, no. 10 (October 2021): 3379–97. http://dx.doi.org/10.1016/j.net.2021.04.020.
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Kim, Kihwan, Byung-Jae Kim, Young-Jung Youn, Hae-Seob Choi, Sang-Ki Moon, and Chul-Hwa Song. "Effect of Flow Blockage on the Coolability during Reflood in a 2×2 Rod Bundle." Science and Technology of Nuclear Installations 2014 (2014): 1–9. http://dx.doi.org/10.1155/2014/247862.
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During the reflood phase of a large-break loss-of-coolant accident (LBLOCA) in a pressurized-water reactor (PWR), the fuel rods can be ballooned or rearranged owing to an increase in the temperature and internal pressure of the fuel rods. In this study, an experimental study was performed to understand the thermal behavior and effect of the ballooned region on the coolability using a 2 × 2 rod bundle test facility. The electrically heated rod bundle was used and the ballooning shape of the rods was simulated by superimposing hollow sleeves, which have a 90% blockage ratio. Forced reflood tests were performed to examine the transient two-phase heat transfer behavior for different reflood rates and rod powers. The droplet behaviors were also investigated by measuring the velocity and size of droplets near the blockage region. The results showed that the heat transfer was enhanced in the downstream of the blockage region, owing to the reduced flow area of the subchannel, intensification of turbulence, and deposition of the droplet.
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Sheppard, Mary N. "Takotsubo Syndrome — Stress-induced Heart Failure Syndrome." European Cardiology Review 10, no. 2 (2015): 83. http://dx.doi.org/10.15420/ecr.2015.10.2.83.
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Takotsubo syndrome has been established as an entity in the past 30 years, particularly with the introduction of interventional angiography for investigation of chest pain. Typically, it occurs in middle-aged females as a response to a stressful event, such as bad news, death, accident, natural disaster, etc. but there is not always a specific trigger. Takotsubo mimics acute myocardial infarction with electrocardiogram changes and elevated troponins. On interventional angiography the coronary arteries are normal with typical apical ballooning of the left ventricle. This feature led to its descriptive name, given by Japanese cardiologists, as the left ventricle resembles a lobster trap with a narrow neck extending into a round ventricle. This leads to a reduction in cardiac function. Takotsubo is believed to be a response to catecholamine release following a stressful event resulting in temporary myocardial damage. It usually has a benign course with spontaneous return of cardiac function. However it may recur and in a small percentage of patients can result in sudden cardiac death with arrhythmia, acute myocardial infarction and cardiac rupture. It is usually treated symptomatically depending on the severity of presentation.
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Krishnamoorthy, Parasuram, Jalaj Garg, Abhishek Sharma, Chandrasekar Palaniswamy, Neeraj Shah, Gregg Lanier, Nainesh C. Patel, Carl J. Lavie, and Hasan Ahmad. "Gender Differences and Predictors of Mortality in Takotsubo Cardiomyopathy: Analysis from the National Inpatient Sample 2009-2010 Database." Cardiology 132, no. 2 (2015): 131–36. http://dx.doi.org/10.1159/000430782.
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Objectives: Takotsubo cardiomyopathy (TC) is characterized by left-ventricle apical ballooning with elevated cardiac biomarkers and electrocardiographic changes similar to an acute coronary syndrome. We studied the prevalence, in-hospital mortality, and predictors of mortality in TC. Methods: All patients ≥18 years of age diagnosed with TC were identified in the Nationwide Inpatient Sample (NIS) 2009-2010 database using the 9th revision of the International Classification of Diseases (ICD) 429.83. Demographics, conventional risk factors (diabetes, hypertension, hyperlipidemia, and tobacco abuse), acute critical illnesses like sepsis, acute cerebrovascular disease (cerebrovascular accident; CVA), acute respiratory insufficiency, and acute renal failure, and chronic conditions (anxiety, depression, and malignancy) were studied. Results: The prevalence of TC was 0.02% (n = 7,510). The total in-hospital mortality rate was 2.4%, with a higher mortality in men (4.8%) than in women (2.1%). Sepsis (9 vs. 4.2%; p < 0.01) was more prevalent in men with an increased prevalence of other critical illness, although this was not statistically significant. Age (OR 1.05; 95% CI 1.01-1.09), malignancy (OR 3.38; 95% CI 1.35-8.41), acute renal failure (OR 5.4; 95% CI 2.2-13.7), acute CVA (OR 9.4; 95% CI 2.96-29.8), and acute respiratory failure (OR 11.1; 95% CI 3.9-31.1) predicted mortality in fully adjusted models. Conclusion: A higher mortality was seen in men, likely related to the increased prevalence of acute critical illnesses, ventricular arrhythmia, and sudden cardiac arrest. Acute CVA and respiratory failure were the strongest predictors of mortality.
Books on the topic "Ballooning accidents"
Book chapters on the topic "Ballooning accidents"
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Jensen, William B. "Richard Abegg and the Periodic Table." In Mendeleev to Oganesson. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780190668532.003.0016.
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The German chemist Richard Wilhelm Heinrich Abegg (Fig. 13.1), was born on 9 January 1869 in Danzig (now Gdansk, Poland) (1). He received his PhD in 1891 from the University of Berlin for work in the field of organic chemistry done under the direction of August Hofmann. He switched to the new and rising field of physical chemistry immediately upon graduation, doing postdoctoral work in the laboratories of Wilhelm Ostwald at Leipzig and Svante Arrhenius at Stockholm, as well as serving as personal assistant to Walther Nernst at Göttingen. In 1897 Abegg was appointed professor of chemistry at the University of Breslau (now Wroclaw, Poland). In 1909 he moved to the local Technischen Hochschule, where he remained until his untimely death on 3 April 1910 at age 41 in a ballooning accident near Koszalin in what is now modern-day Poland. As might be inferred from his association with Ostwald, Arrhenius, and Nernst, Abegg’s research interests quickly focused on the newly formulated theories of ionic dissociation and chemical equilibrium, where he is credited with contributing to an understanding of the theory of freezing point depression and with writing two popular introductory textbooks on the use of the ionic theory and equilibrium in reinterpreting various traditional areas of chemical synthesis and analysis (2, 3). With the discovery of the electron in 1897 Abegg soon became interested in its use to rationalize various electrochemical phenomena and in its possible implications for both the periodic table and chemical bonding. That year he published, in collaboration with Guido Bodländer, his theory of electroaffinity in which he postulated that electrochemical half-cell oxidation potentials could be used as a measure of an atom’s attraction for electrons and that this, in turn, could be qualitatively correlated with periodic trends (Fig. 13.2) in such properties as molecular polarity, solubility, and the tendency to form complex ions (4, 5).
Conference papers on the topic "Ballooning accidents"
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Yoon, Kyungmin, Chansu Jang, and Jooil Yoon. "A Study on Doppler Weighting Factor for Control Element Assembly Ejection Accident by Using Newly Developed Nuclear Design Code and Non-LOCA Methodology." In ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-65996.
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Among Reactivity Initiated Accidents (RIAs) for Pressurized Water Reactor (PWR), Control Element Assembly Ejection (CEAE) accident causes the rapid positive reactivity insertion to the core. It causes an asymmetric power distortion which results in the rising of local fuel temperature, fuel pellet thermal expansion and cladding ballooning or rupture. In the CEAE accident, Doppler feedback has a profound effect because the negative reactivity insertion due to the rise of fuel temperature reduces the core power after rapid power excursion. But the Doppler reactivity can’t be calculated properly in the safety analysis code, using point kinetics model, because the point kinetics model is not able to consider spatial-time effect of the sudden rise in local fuel temperature on Doppler feedback calculation during CEAE accident. And then the excessively high core power which results from the underestimated Doppler feedback would make more severe results such as PCMI fuel failure, fuel cladding rupture and serious DNB fuel failure. Therefore, Doppler Weighting Factor (DWF) is needed for the safety analysis of CEAE accident to compensate a missing spatial-time effect on Doppler feedback calculation. In this study, the adequacy of the application of DWF for APR1400 was evaluated by using nuclear design code called ASTRA (Advanced Static and Transient Reactor Analyzer)[1] and a methodology called ISAM (Integrated Safety Analysis Methodology)[2]. ASTRA is the 3D nuclear design code newly developed by KNF and has various functions such as the static core design, the transient core analysis and the operational support. ISAM is the methodology which is newly developed by KNF to perform the Non-LOCA safety analysis by using RETRAN[3] code which is widely used in the transient analysis and based on the point kinetics model.
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Kumar, Ravi, Gopal Nandan, P. K. Sahoo, B. Chatterjee, D. Mukhopadhyay, and H. G. Lele. "Ballooning of Pressure Tube Under LOCA in an Indian Pressurised Heavy Water Reactor." In 2010 14th International Heat Transfer Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/ihtc14-23011.
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A study has been carried out by experimental simulation of the loss of coolant accident (LOCA) in an Indian pressurized heavy water reactor (IPHWR). The experiment has been carried out taking a completely voided fuel channel of Indian PHWR at 40 bar inside pressure as test-section. In order to simulate the rate of heat generation during LOCA, the pressure tube (PT) was electrically heated with a 12VDC/3500A rectifier. Initially the set-up was maintained at 300 °C temperature by resistance heating of PT. After attaining nearly steady state a step input of 21 kW electrical heating was given to the test-section which resulted in the temperature rise of PT with a gross rate of 2.8 °C/s. The ballooning deformation of test-section tube i.e. PT initiated at 575 °C temperature. With the progress of ballooning the rate of temperature rise was reduced due to high heat transmission to CT and subsequently to water in the tank surrounding CT. The pressure tube (PT) and calendria tube (CT) contact established at the average PT temperature of 680 °C. The contact was also confirmed from the average temperature profile of CT.
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Ho, Ai-Ling, Jong-Rong Wang, Hao-Tzu Lin, and Chunkuan Shih. "Analysis of the Control Rod Drop Accident (CRDA) for Lungmen ABWR." In 2014 22nd International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/icone22-30838.
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The object of this paper is to understand the realistic behavior in Lungmen ABWR (Advanced Boiling Water Reactor) during a control rod drop accident (CRDA) transient. The CRDA transient would lead the reactor through an extremely fast and localized power excursion, requiring an accurate core modeling. The CRDA analysis for Lungmen ABWR was performed by coupling the 3D neutron kinetic code, PARCS, and two-phase thermal-hydraulic (T-H) code, TRACE. After TRACE/PARCS coupling calculation, the output data from TRACE/PARCS would be inputted into FRAPTRAN code as a function of time-dependent fuel rod power and coolant boundary conditions to calculate the fuel damage. The CRDA analysis for Lungmen ABWR was performed for two conditions: a) case1: hot-full-power (HFP) at beginning of cycle (BOC); b) case2: hot-zero-power (HZP) at BOC. Under these conditions, the damage mechanisms of fuel rod are: 1) cladding ballooning and burst; 2) embrittlement and failure by high-temperature oxidation; 3) melting of cladding and/or fuel pellets. And the relevant quantities for fuel performance are the maximum fuel enthalpy and the melting temperatures of cladding and fuel pellet. The results of CRDA analysis show that a) case1: no fuel failure occurs under HFP condition at BOC; b) case2: the fuel rod nearby the dropped control rod failed under HZP condition at BOC, and the FRAPPTRAN data exposes that the main reason of rod failure is the cladding high temperature.
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Soloviev, Sergei L., Boris A. Gabaraev, Leonid M. Parafilo, Dmitry V. Kruchkov, Oleg Yu Novoselsky, Vladimir N. Filinov, and Oleg I. Melikhov. "Integrated Analysis of Mechanical and Thermal Hydraulic Behavior of Graphite Stack in Channel-Type Reactors in Case of a Fuel Channel Rupture Accident." In 10th International Conference on Nuclear Engineering. ASMEDC, 2002. http://dx.doi.org/10.1115/icone10-22338.
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The paper discusses the methodology and a computational exercise analyzing the processes taking place in the graphite stack of an RBMK reactor in case of a pressure tube rupture caused by overheating. The methodology of the computational analysis is implemented in integrated code U_STACK which models thermal-hydraulic and mechanical processes in the stack with a varying geometry, coupled with the processes going on in the circulation loop and accident localization (confinement) system. Coolant parameters, cladding and pressure tube temperatures, pressure tube ballooning and rupture, coolant outflow are calculated for a given accident scenario. Fluid parameters, movement of graphite blocks and adjacent pressure tubes bending after the tube rupture are calculated for the whole volume of the core. Calculations also cover additional loads on adjacent fuel channels in the rupture zone, reactor shell, upper and lower plates. Impossibility of an induced pressure tube rupture is confirmed.
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Villanueva, Walter, Chi-Thanh Tran, and Pavel Kudinov. "Effect of CRGT Cooling on Modes of Global Vessel Failure of a BWR Lower Head." In 2012 20th International Conference on Nuclear Engineering and the ASME 2012 Power Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/icone20-power2012-54955.
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An in-vessel stage of a severe core melt accident in a Nordic type Boiling Water Reactor (BWR) is considered wherein a decay-heated pool of corium melt inflicts thermal and mechanical loads on the lower-head vessel wall. This process induces creep leading to a mechanical failure of the reactor vessel wall. The focus of this study is to investigate the effect of Control Rod Guide Tube (CRGT) and top cooling on the modes of global vessel failure of the lower head. A coupled thermo-mechanical creep analysis of the lower head is performed and cases with and without CRGT and top cooling are compared. The debris bed heat-up, re-melting, melt pool formation, and heat transfer are calculated using the Phase-change Effective Convectivity Model and transient heat transfer characteristics are provided for thermo-mechanical strength calculations. The creep analysis is performed with the modified time hardening creep model and both thermal and integral mechanical loads on the reactor vessel wall are taken into account. Known material properties of the reactor vessel as a function of temperature, including the creep curves, are used as an input data for the creep analysis. It is found that a global vessel failure is imminent regardless of activation of CRGT and top cooling. However, if CRGT and top cooling is activated, the mode and timing of failure is different compared to the case with no CRGT and top cooling. More specifically, with CRGT and top cooling, there are two modes of global vessel failure depending on the size of the melt pool: (a) ‘ballooning’ of the vessel bottom for smaller pools, and (b) ‘localized creep’ concentrated within the vicinity of the top surface of the melt pool for larger pools. Without CRGT and top cooling, only a ballooning mode of global vessel failure is observed. Furthermore, a considerable delay (about 1.4 h) on the global vessel failure is observed for the roughly 30-ton debris case if CRGT and top cooling is implemented. For a much larger pool (roughly 200-ton debris), no significant delay on the global vessel failure is observed when CRGT and top cooling is implemented, however, the liquid melt fraction and melt superheat are considerably higher in non-cooling case.
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Ma, Zehua, Koroush Shirvan, Wei Li, and Yingwei Wu. "Modeling Axial Relocation of Fragmented Fuel During Loss of Coolant Conditions by Using ABAQUS." 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/icone2020-16291.
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Abstract In a light-water reactor, during normal operating condition, the UO2 nuclear fuel pellets undergo fragmentation primarily due to presence of thermal stresses, fission gas development and pellet-clad mechanical interaction. Under Loss of Coolant Accident (LOCA) conditions, a portion of fuel fragments can freely move downwards to the ballooning region due to the significant cladding deformation. The fuel relocation can localize the heat load and in turn accelerate the cladding balloon and burst process. Cladding burst is of great concern because of the potential for fuel dispersal into coolant and clad structural stability. In our work, we built up a finite element model considering cladding balloon, fuel relocation and its resultant thermal feedback during LOCA condition with ABAQUS. The clad balloon model includes phase transformation, swelling, thermal and irradiation creep, irradiation hardening and annealing and other important thermal-mechanical properties. The mass of relocation model was verified against the analytical cases of single balloon and twin balloons. The cladding balloon model combined with fuel thermal conductivity degradation was verified against fuel performance code, FRAPTRAN. Finally, with the evolution of pellet-cladding gap, the fuel mass relocation was calculated and compared against the IFA-650.4 transient test from the Halden reactor.
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Luxat, J. C. "Dynamic Sensitivity Analysis of Thermal-Mechanical Deformation of a CANDU Fuel Channel." In 16th International Conference on Nuclear Engineering. ASMEDC, 2008. http://dx.doi.org/10.1115/icone16-48656.
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In a limiting critical break loss of coolant accident in a CANDU reactor significant degradation of heat transfer from the fuel can occur. As a result of the subsequent increase in fuel temperature it is possible that the pressure tube undergoes heat up at intermediate pressure during blowdown. This can result in ballooning deformation of the pressure tube into contact with its calandria tube. It is required that fuel channels not fail as a consequence of the thermal mechanical deformation of the pressure tube and calandria tube in such events. Dynamic sensitivity functions are derived as analytical partial differential equations derived from the equations used to model the time-dependent behavior of physical systems. The dynamic sensitivity functions can be used to propagate uncertainties using a time-dependent perturbation approach in which the variations in a set of output variables, with respect to perturbations of the input parameters, are evaluated about reference response trajectories of the input parameters and associated output variables. The dynamic sensitivity method is described in this paper and results are presented for the pressure tube heatup phase of a LOCA. These results show the importance of all key parameters with respect to specified safety evaluation criteria. The dynamic sensitivity method is applied in a probabilistic uncertainty analysis to evaluate the probability of a pressure tube experiencing creep strain deformation to contact its calandria tube during the early stages of a LOCA.
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Yadav, Ashwini K., Ravi Kumar, Akhilesh Gupta, P. Majumdhar, B. Chatterjee, and H. G. Lele. "An Experimental Investigation on the Behaviour of Pressure Tube Under Symmetrical and Asymmetrical Heating Conditions in an Indian PHWR." In ASME 2011 Small Modular Reactors Symposium. ASMEDC, 2011. http://dx.doi.org/10.1115/smr2011-6533.
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Thermal behavior of fuel channel under loss of coolant accident (LOCA) is a major concern for nuclear reactor safety. LOCA along with failure of emergency cooling water system (ECC) may leads to mechanical deformations like sagging, ballooning or even release of containment in open atmosphere due to breaching of pressure tube (PT) under certain depressurization and voiding rates. In order to understand the phenomenon an experiment has been carried out using 19 pin fuel element simulator. Main purpose of the experiment was to trace temperature profiles over the pressure tube, calandria tube and clad tubes of Indian Pressurized Heavy Water Reactor (IPHWR) under symmetrical and asymmetrical heat-up conditions. For simulating the fully voided scenario, symmetrical heating of pressure was carried out by injecting 13.2 KW (2% of nominal power) to all the 19 pins and the temperatures of pressure tube, calandria tube and clad tubes were measured. During symmetrical heating the sagging of fuel channel was initiated at 460 °C and the highest temperature attained by PT was 650 °C. The decay heat from clad tubes was dissipated to moderator mainly by radiation and natural convection. The highest temperature of 680 °C was observed over the outer ring of clad tubes of fuel simulator. Again, to simulate partially voided condition, asymmetrical heating of pressure was carried out by supplying 8.0 kW power to upper 8 pins of fuel simulator and temperature profiles were measured. Along the circumference of pressure tube (PT) the highest temperature difference of 320 °C was observed, which highlights the magnitude of thermal stresses and their role in breaching of pressure tube under partially voided conditions. However, the integrity of pressure tube was intact during both symmetrical and asymmetrical heat-up conditions.
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Trancossi, Michele, Antonio Dumas, and Mauro Madonia. "Energy and Mission Optimization of an Airship by Constructal Design for Efficiency Method." In ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-63448.
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It is possible to define a novel design method, which aims overcoming both traditional, the traditional Multidisciplinary Design Optimization, and to solve a fundamental issue relating to the actual formalization of the Constructal optimization method. It aims only to enhance and integrate the constructal design method and aims to produce designs, which could be, optimized both at system level and subsystem definition. This novel method is based on the second principle of thermodynamics and the constructal law. It aims to produce a design process based on two steps. The first step aims producing a theoretical design of a system to reach energetic and operative optimization. The second aims to optimize the subcomponents of the system according the bottom up approach defined by constructal design optimization. A third step relating to the readiness against technology analysis is necessary to develop an effective industrial design. This method has named Constructal Design for Efficiency. In this paper the authors, starting from the experience produced by the MAAT EU FP7, about the design of a cruiser-feeder and energy self sufficient airship for transport has produced the optimization of a medium altitude airship for transport, focused on the optimization of flying vehicle architecture to minimize by design the energy consumption during flight. The produced results allow defining a novel airship concept, which optimizes the airship shape to reach three fundamental energetic goals: energy consumption minimization; photovoltaic energy production maximization; definition of the conditions for energetically self-sufficient flight. The defined architecture can maximize the operative possibilities realizing an airship, which can ensure a point-to-point ground, based logistic models without any airport infrastructure with potential breakthrough impacts because of a better integration with any other terrestrial, maritime and aerial transport mode. Notwithstanding the use of hydrogen, it ensures an increased perception of safety by potential customers. It presents a safer ballooning architecture, without internal air ballonets, a cabin not directly attached to the bottom part of the balloon, which can be detached and piloted safely on the ground in case of serious accident during flight.
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Rhee, Bo W., H. T. Kim, and Y. M. Song. "Reconsideration of a Scaling Study of CANDU-6 Moderator Tank Scaled-Down Test Facility." In 2014 22nd International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/icone22-30315.
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According to the literature survey, several scaling studies have been performed to derive a set of scaling criteria which were thought to be suitable for reproducing the major thermal-hydraulic phenomena in a scaled-down CANDU moderator tank similar to that in a prototype power plant during a full power steady state condition [1,2,3]. The objective of building this scaled-down moderator tank is to generate the experimental data necessary to validate the computer codes which are used to analyze the accident analysis of CANDU-6 plants. The major variables of interests in this paper are moderator flow velocity and temperature of the moderator which is D2O inside the moderator tank during a steady state and transient conditions. The reason is that the local subcooling of the moderator is found to be a critical parameter determining whether the stable film boiling can sustain on the outer surface of the calandria tube if the contact of overheated pressure tube and cold calandria tube should occur due to pressure tube ballooning during LBLOCA with ECC injection failure[4]. The key phenomena involved include the inlet jet development and impingement, buoyancy force driven by the moderator temperature gradient caused by non-uniform direct heating of the moderator, and the pressure drop due to viscous friction of the flow across the calandria tube array. In this paper, the previous researches are reviewed, some concerns or potential problems associated with them implied by comparing CFD analyses results between the CANDU-6 moderator tank and 1/4 scaled-down test facility are described, and as a way to examine the assumption of the scaling analysis is true an order-of-magnitude analyses are performed. Based on the results of these analyses the assumption of neglecting (∇*)2V* .and (∇*)2T* terms cannot be justified for the power of 0.5 MW and 1.566 MW for the 1/4 scaled-down facility. Further investigation is thought to be necessary to confirm this result, i.e. if the scaling of the previous work1 is justifiable by some other independent analyses.