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Riskkommunikation genom flera kommunikationsvägar : En studie baserad på haveriutredningarNordblom, Gustav, Laiberg, Louise January 2017 (has links)
Risk communication in a modern maritime environment is unmistakably important but how does it fare against today’s science? This study focuses on a small part of risk communication, namely the differences in using one mean of communication as opposed to multiple means of communication. What positive and negative sides are involved in exchanging information through only one mean of communication as opposed to giving and receiving the information through many? The method is a literature study and the material ten accident reports made by administrative authorities. The reports have been analyzed and compared to modern subject science literature. The result of the study favor multiple means of communication such as public address systems, signs, general alarm and through the crew. The different ways create a redundancy and succeeds better at reaching a diversity of people. The negative sides, including confusion caused by too much or deviating information, appears to historically have been exaggerated. This is probably due to a false belief that man behaves irrationally in a state of crisis. The risk communication of the future is as such thick in information and comes through multiple means of communication.
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Odpovědnost za škodu při pracovních úrazech a nemocech z povolání / Liability for damage regarding occupational accidents and illnessLachnit, Ondřej January 2011 (has links)
Ondřej Lachnit Liability for Damage Regarding Occupational Accidents and Illness The following thesis deals with the issue of liability for damage regarding occupational accidents and illness in the Czech Republic. At the present time, employer's liability conforms to the Labour Code from 2006, which builds on the preceding Labour Code from the year 1965. A rich judicature concerning occupational accidents and illness has been formed since the 1960s. In this thesis, I often quote from this judicature. The current Labour Code, however, only provisionally deals with this issue; an ensuing change is about to take place due to the passing of a new law concerning the workers' compensation insurance. This law is already valid, but has yet to become operative. The law will come into effect on January 1st, 2013. Whether the law will become operative is questionable as its legal effect depends on the political situation in the Czech Republic. Currently, the right-wing government does not favour the new law, since it would burden the state budget more than the current system. In the Czech Republic, the employer's liability for damage regarding occupational accidents is defined very broadly:...
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Vývoj pojištění majetku obyvatelstva na českém pojistném trhu / Development of property insurance for citizens in the Czech RepublicKopecká, Kamila January 2017 (has links)
The master thesis analyzes the property insurance for citizens in the Czech Republic with main focus on buildings insurance, household insurance, and accident insurance for non-rail vehicles. The goal of this thesis is to analyze the development of insurance market indicators of the products stated above and to predict their future behavior. To help with the understanding of the practical part, basic terminology and trends in the general insurance market are included in this work. The main indexes to be analyzed are: premium written, claims paid, loss ratio, number of contracts made, average written premium per contract, number of claims settled, average written premium per insured event, and the number of commercial insurance companies. The main data sources for time series analysis for the period between the years 1997 and 2015 are the annual reports of the Czech Insurance Association. The time series analysis showed that building insurance and household insurance are strongly affected by natural disasters - in the Czech Republic the main impact have floods. Since the main purpose of the accident insurance is to cover accidents, it is only partially impacted by natural disasters. The popularity of property insurance has an increasing tendency, which is shown by the insurance market indicators. Box-Jenkins methodology was used to forecast the future development of the insurance market. Similarly to other insurance products, the property insurance undergoes certain changes, to which the insurance companies must respond. These trends are mainly connected to the higher usage of modern technologies - for instance Internet of Things, introduction of Smart Homes or the ,,Pay How-You-Drive'' insurance.
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Etude des effets dominos sur une zone industrielle / Study of domino effect in an industrial areaAlileche, Nassim 14 December 2015 (has links)
Les effets dominos ou cascade d’événements dans les industries et particulièrement dans les industries chimiques et de transformation, sont reconnus comme des scénarios d’accidents possibles depuis environ trois décennies. Ils représentent une préoccupation croissante, car ils ont le potentiel de provoquer des conséquences dévastatrices. L’effet domino, comme phénomène, est un sujet controversé lorsque son évaluation est nécessaire. L’examen de la bibliographie a démontré l’absence d’une définition commune et d’une procédure simple d’utilisation et précise pour son appréciation. C’est pourquoi l’un des objectifs de cette recherche est de formaliser les connaissances relatives aux effets dominos afin de comprendre les mécanismes de leurs occurrences. Pour ce faire nous avons étudié les paramètres à examiner pour déterminer la possibilité de cascade et être en mesure d’identifier les scénarios dominos. L’enjeu étant de permettre l’amélioration de la prévention du risque d’effet domino. L’autre objectif est donc de produire une méthode pour l’identification et l’analyse des effets dominos. Nous avons développé une méthodologie globale pour l’étude des effets dominos en chaîne initiés par des pertes de confinement. Elle permet l’identification et la hiérarchisation des chemins de propagation des accidents. Cette méthode facilite la prise de décision pour la prévention des effets dominos, tout en proposant un outil efficace et simple d’utilisation. Les résultats de l’étude sont fournis sous forme d’une hiérarchisation quantitative des équipements impliqués dans les scénarios dominos, en tenant compte des effets des conditions météorologiques et des mesures de maîtrise des risques existantes ou proposées.Cette hiérarchisation donne une idée claire des dangers que représentent les équipements par rapport aux accidents en cascade, en précisant si la dangerosité de l’équipement provient de sa capacité à initier ou à propager un effet de cascade.La méthode est basée sur une description topographique de la zone étudiée, incluant les caractéristiques de chaque équipement, et prend en compte les mesures de maîtrise des risques mises en œuvre par l’industriel. Elle repose sur deux phases principales : La première, est l’identification des chemins de propagation des accidents. Pour ce faire, la méthode d’analyse par arbre d’événements est utilisée. Les cibles potentielles sont déterminées en combinant les valeurs seuils d’escalade et les modèles de vulnérabilité (pour l’estimation de la probabilité d’endommagement). Cette première phase est implémentée sous MATLAB® et Visual Basic for Applications (VBA) afin de faciliter l’entrée des données, et l’analyse des résultats dans Microsoft Excel®. La deuxième phase est l’identification des équipements les plus dangereux vis-à-vis des effets dominos. Elle consiste à hiérarchiser les équipements impliqués dans les chemins de propagation, en fonction de leur vraisemblance à causer ou à propager un effet domino. L’algorithme qui effectue cette phase est codé sous VBA. La méthode a été conçue de façon à ce qu’elle puisse être utilisée sans qu’il soit nécessaire de s’appuyer sur les résultats des études de dangers. Néanmoins, si ces résultats sont disponibles, il est alors possible d’alléger certaines étapes de la méthode. Elle s’est révélée facile à utiliser, cela a été constaté lors de son application dans le cadre de projets et stages d’étudiants. / Domino effects or cascading events in the chemical and process industries are recognized as credible accident scenarios since three decades. They are raising a growing concern, as they have the potential to cause catastrophic consequences. Domino effect, as phenomenon, is still a controversial topic when coming to its assessment. There is still a poor agreement on the definition of domino effect and its assessment procedures. A number of different definitions and approaches are proposed in technical standards and in the scientific literature. Therefore, one of this research objectives is to formalize domino effects knowledges in order to comprehend their occurrence mechanisms. Thus, the parameters that should be looked at so as to understand the escalation possibility and in order to identify domino scenarios, were analyzed. The aim is to improve domino effect hazards prevention, through the development of a methodology for the identification and the analysis of domino effects.We developed a method for the analysis of domino accident chain caused by loss of containments. It allow the identification and prioritization of accident propagation paths. The method is user-friendly and help decision making regarding the prevention of cascading events. The final outcomes of the model are given in form of quantitative rankings of equipment involved in domino scenarios, taking into account the effect of meteorological conditions and safety barriers. The rankings give a clear idea of equipment hazard for initiating or continuing cascading events.The methodology is based on a topography of the industrial area of concern, including the characteristics of each unit and accounting for protection and mitigation barriers. It is based on two main stages. The first is the identification of accident propagation paths. For this, the event tree method is used. The possible targets are identified combining the escalation thresholds and vulnerability models (to estimate damage probability). This first stage was implemented using the MATLAB® software and Visual Basic for Applications (VBA) to enable an easy input procedure and output analysis in Microsoft Excel®.The second stage is the identification of the most dangerous equipment. It consists in prioritizing equipment involved in the propagation paths according to their likelihood to cause/propagate domino effect. The algorithm that performs this phase was coded in VBA.The method was designed so as it can be used without the need to rely on the results of safety reports. However, if such results are available, it is possible to lighten some steps of the method. It revealed easy to apply, this was confirmed through projects and student internships. / Gli effetti domino, in cui un primo incidente causa in cascata altri scenari incidentali, sono tragli scenari incidentali più severi che avvengono nell’industria chimica. Nonostante l’attenzioneche anche la normativa dedica a tali scenari, la valutazione dell’effetto domino è un soggettocontroverso. L’analisi della letteratura tecnica e scientifica ha mostrato l’assenza di unadefinizione comune di « effetto domino » e di una semplice procedura per l’identificazione ditali scenari. È per tale motivo che uno degli obiettivi di questo lavoro di ricerca è diformalizzare le conoscenze relative agli effetti domino al fine di meglio comprendere imeccanismi che possono provocarli. A tal proposito sono stati studiati i parametri necessariper determinare la possibilità dell’insorgere di cascate di eventi e per essere in grado diidentificare i possibili scenari incidentali dovuti ad effetto domino. L’obiettivo finale del lavoroè stato di sviluppare un metodo per l’identificazione e l’analisi quantitativa della propagazionedi incidenti primari nell’ambito di scenari dovuti ad effetto domino.E’ stata sviluppata una metodologia generale per l’analisi degli effetti domino causati daperdite di confinamento. Tale metodologia permette l’identificazione e la classificazione deipercorsi di propagazione degli incidenti. Tale metodo facilita inoltre la prevenzione deglieffetti domino, proponendo uno strumento efficace e semplice da utilizzare.I risultati di questo studio sono forniti in forma di una classificazione delle apparecchiaturecoinvolte in scenari dovuti ad effetto domino, tenendo conto degli effetti delle condizionimeteorologiche e delle misure esistenti per la gestione del rischio. Tale classificazione fornisceanche un chiara idea dei pericoli rappresentati dalle singole apparecchiature nel caso diincidenti in cascata, in quanto precisando se la pericolosità delle attrezzature proviene dallaloro capacità di innescare o propagare un reazione a catena.Il metodo è basato su una descrizione topografica del sito studiato, che comprende anche lecaratteristiche di ogni attrezzatura, che tiene conto delle misure di gestione dei rischi e dellebarriere di sicurezza presenti, basato su due fasi principali. La prima è l’identificazione deipercorsi di propagazione degli incidenti. A tale scopo è stato utilizzato un metodo basatoVIsull’albero degli eventi. I potenziali bersagli vengono determinati combinando i valori di sogliaper la propagazione degli eventi ed i modelli di vulnerabilità delle apparecchiature. Questaprima fase è implementata in MATLAB® e Visual Basic for Applications (VBA) in modo dafacilitare la gestione dei dati e l’analisi dei risultati in Microsoft Excel®.La seconda fase è l’identificazione delle apparecchiature più pericolose per gli effetti domino.Tale fase consiste nel classificare le apparecchiature coinvolte nei percorsi di propagazione infunzione della loro capacità di causare o propagare un effetto domino. L’algoritmo dedicato inquesta fase è eseguito su VBA.I risultati ottenuti anche nell’applicazione ad un caso di studio hanno evidenziato le potenzialitàdel metodo, che rappresenta un significativo progresso nell’analisi quantitativa dell’effetto domino.
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Influence de la fermentation intestinale sur le risque d'accident de désaturation / Influence of gut fermentation on the risk of decompression sicknessMaistre, Sébastien de 14 December 2016 (has links)
L’accident de désaturation (ADD) est un accident de plongée lié à la charge en gaz diluants pendant la plongée, et à la formation de bulles dans l’organisme au cours de la décompression. Il est susceptible d’engendrer des séquelles neurologiques. Au cours de plongées utilisant l’hydrogène comme gaz diluant, la diminution de la charge tissulaire en hydrogène par l’inoculation au niveau de l’intestin de bactéries métabolisant ce gaz réduit le risque d’ADD.L’objectif de ce travail était d’évaluer si inversement : 1) la fermentation intestinale lors de la plongée peut favoriser la survenue d’un ADD, par l’intermédiaire de la production d’hydrogène endogène ; 2) la stimulation chronique de la fermentation avant plongée majore le risque d’ADD.Nos résultats sont en faveur d’un effet dual de la fermentation intestinale sur la décompression. Délétère à court terme lors de la plongée, la fermentation intestinale prolongée pourrait être favorable en dehors de la plongée en prévenant la survenue et la sévérité d’un ADD. L’hydrogène, molécule aux propriétés antioxydantes, et le butyrate, un acide gras à chaîne courte, sont en effet deux produits de la fermentation des hydrates de carbone qui ont des vertus neuroprotectrices.La prévention des accidents de désaturation pourrait passer par une exclusion des plongeurs présentant une fermentation importante le jour de la plongée, une élimination des gaz produits au niveau de l’intestin ou une modification de l’alimentation dans les 24 heures précédant une plongée. En revanche, tous les facteurs susceptibles de modifier le microbiote intestinal et d’augmenter la fermentation, en dehors de la plongée, pourraient être testés en prévention de l’ADD. En outre, l’hydrogène et le butyrate pourraient jouer un rôle bénéfique dans le cadre du traitement de l’ADD / Decompression sickness (DCS) is a diving accident related to the dissolution of diluent gas in blood and tissues during a dive, followed by bubble formation in the body during decompression. It can lead to neurological damage. In dives using hydrogen as the diluent gas, the concentration of hydrogen in the tissues can be reduced by the presence in the gut of bacteria capable of metabolising this gas and this reduces the risk of DCS.The aim of this work was conversely to check if: 1) fermentation in the gut at the time of diving could exacerbate DCS as a result of endogenous hydrogen generation; 2) long-term stimulation of fermentation before diving raises the risk of DCS.Our findings point to a two-edged effect of intestinal fermentation on decompression: although deleterious in the short term, i.e. at the time of diving, longer-term intestinal fermentation between dives might have a positive effect by preventing the occurrence of DCS and limiting its severity. Indeed, hydrogen which has antioxidant properties and butyrate, a short-chain fatty acid, are both by-products of the fermentation of carbohydrate and both have neuroprotective activity.DCS prevention could be promoted by excluding divers exhibiting strong fermentation on the day of a dive, by the elimination of gases being produced in gut or by modification of diet in the 24 hours before a dive. On the other hand, any factor that might affect the gut microbiota and stimulate fermentation between dives could be tested to investigate its potential in protecting against DCS. Furthermore, hydrogen and butyrate could play a positive role when it comes to treating DCS
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The perceptions of accident and emergency nurses regarding a structured debriefing programme in a private hospital in GautengVan Heerden, Marius 15 October 2007 (has links)
The aim of this study was to determine Accident and Emergency (A&E) nurses’ perceptions of a structured debriefing programme based on the model of SP Hattingh. Objectives of the research were to train A&E nurses as peer debriefers to be able to implement a structured debriefing programme, to then implement it and finally to determine the debriefed A&E nurses and debriefers’ perceptions of the structured debriefing programme. A contextual, explorative, descriptive research design, using qualitative methodology, was adopted. The population for this study was all registered nurses working in an A&E unit in a private hospital in Gauteng. Three main themes were identified, namely: positive aspects, negative aspects and recommendations for implementation. Recommendations were made to optimise the use of this programme in the future. / Dissertation (MCur (Clinical))--University of Pretoria, 2007. / Nursing Science / MCur / unrestricted
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Srovnání Fraud Managemet Systémů z pohledu společnosti/zákazníka (na co si dát pozor a na co se zaměřit při výběru vhodného řešení) / Comparison of Fraud management systems from customers point of view: What to be avare of and where to focus, while selecting proper solution.Augusta, Jindřich January 2009 (has links)
Diploma thesis deals with fighting insurance fraud from the very beginning to the end, seen from insurance company's perspective. It also tries to see insurance frauds and dealing with them not only from IT point of view, but also accompany other department's views and needs. It's starting with organizational overview and its readiness to fight fraud and trying to show, how to improve. Furthermore it introduces reader with basic terms and phrases of insurance fraud and continues with general description of this encounter. It continues with indicators of insurance fraud and its examples and strategies, how to find them in data. Next part of my thesis is focusing on available external sources and possible insurance companies' cooperation, for maximized ability to detect suspicious cases. This is continued by selection of proper system, requirements definition and its goals. Last part shows one of FMS solutions and its description, from requirements up to complete solutions architecture and screenshots of given system.
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Etude des atteintes de la substance blanche liées aux performances motrices et de langage des patients après un accident vasculaire cérébral / Study of white matter damage related to motor and speech performance of stroke patientsVargas, Patricia 19 February 2014 (has links)
L'imagerie par tenseur de diffusion (DTI) est une technique qui permet d'étudier l'organisation et l'état structurel des faisceaux de substance blanche. L'étude de l'intégrité des faisceaux peut aider à comprendre et à déterminer la sévérité du pronostic des patients après un accident ischémique cérébral (AIC). Dans cette thèse, je présente deux études ; dans la première nous avons comparé les résultats obtenus à partir d'un template du faisceau Corticospinal (FCS) à ceux obtenus par la tractographie chez des sujets sains et des patients post-AIC. Dans les deux groupes, les valeurs de la fraction d'anisotropie (FA) obtenues avec la tractographie étaient plus élevées que celles du template. Cependant, chez les patients, les deux méthodes ont détecté une diminution des valeurs de FA du FCS ipsilésionnel, qui était corrélée aux scores moteurs, mais les valeurs de FA obtenues avec le template étaient mieux corrélées avec le signal BOLD généré par la main parétique. La deuxième étude cherchait à savoir si la sévérité de l'aphasie post-AIC pouvait être corrélée à l'atteinte de certaines régions de la substance blanche. L'analyse voxel à voxel a permis d'identifier une zone située à l'intersection des voies dorsale et ventrale du langage, au-dessous de la jonction temporo-pariétale (JTP) gauche. La gravité des dommages dans cette région, évaluée par les valeurs de la FA, était mieux corrélée aux déficits phasiques que le volume de l'infarctus. Dans cette thèse, nous avons trouvé que, après un AIC, l'atteinte du FCS est un bon prédicteur de la sévérité du déficit moteur et celle d'une région localisée au-dessous de la JTP gauche, est un bon prédicteur de la sévérité de l'aphasie. / The diffusion tensor imaging (DTI) is a technique used to study the organization and the structural state of white matter tracts. The study of the tracts integrity may help to understand and determine the severity of the patients? prognosis after an ischemic stroke. In this thesis, I present two studies: in the first we compared the results obtained from a template of the Corticospinal tract (CST) to those obtained by a tractography in healthy subjects and stroke patients. In both groups, the fractional anisotropy (FA) values obtained with the tractography were higher than those obtained by the template. However, in patients, both methods detected a decrease in FA values of the ipsilesional CST, which was correlated with motor scores, but the FA values obtained with the template were better correlated with the BOLD signal generated by the paretic hand. The second study investigated whether the severity of aphasia could be correlated to the damage of certain areas of the white matter. The voxel-based analysis identified an area at the intersection of the dorsal and ventral pathways of language, below the left temporo-parietal junction (JTP). The severity of the damage in this area, assessed by the FA values, was better correlated with the phasic deficits than the infarct volume. In this thesis, we found that after a stroke, the damage of the CST is a good predictor of the motor deficit severity and that of the region located below the left JTP is a good predictor of the aphasia severity.
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Simulação computacional de eventos termo-hidraulicos transitorios em multicircuitos com multibombasVeloso, Marcelo Antonio 02 October 2003 (has links)
Orientadores: Roger Josef Zemp, Paulo de Carvalho Tofani / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Made available in DSpace on 2018-08-03T15:26:11Z (GMT). No. of bitstreams: 1
Veloso_MarceloAntonio_D.pdf: 10344720 bytes, checksum: e173f03cd07f8090cdc60aacf528de23 (MD5)
Previous issue date: 2003 / Resumo: O programa computacional P ANTERA-2 (Programa para Análise Termo-hidráulica de Reatores a Água, Versão 2), cujos fundamentos são descritos neste trabalho, efetua a análise por subcanais de feixes de varetas em conjunção com a simulação de múltiplos circuitos. O programa resolve simultaneamente as equações de conservação da massa, dos momentos axial e lateral e da energia para a geometria de subcanais acopladas com as equações de balanço que descrevem o escoamento de um fluido em um número arbitrário de circuitos de remgeração conectados a um vaso de pressão que contém o feixe. Atendo-se à formulação de subcanais, a estratégia computacional básica de P ANTERA-2 provém dos códigos COBRA, mas um método implícito alternativo de solução orientado para o campo de pressões é usado para resolver as aproximações de diferenças finitas das leis de balanço. Os resultados previstos pelo modelo de subcanais compreendem as distribuições de densidades, entalpias, vazões de massa e pressões nos subcanais. O modelo de circuitos prevê as vazões nos circuitos individuais, a vazão total através do vaso de pressão e as velocidades de rotação das bombas em função do tempo subseqüente à falha de qualquer número das bombas de circulação. Os transitórios de vazão nos circuitos podem ser ocasionados pelas perdas de potência elétrica, ruptura de eixos e travamento de rotores das bombas. As variações nas velocidades de rotação das bombas em função do tempo são determinadas através de um balanço de torques. A altura de recalque e o torque hidráulico das bombas são calculadas em função da velocidade e da vazão com duas curvas homólogas polares fornecidas ao programa na forma tabular. Para ilustrar a capacidade analítica de P ANTERA-2, três problemas-exemplo são apresentados e discutidos. Comparações entre resultados calculados e medidos indicam que o programa reproduz com boa precisão dados experimentais de temperaturas de saída de subcanais e de fluxos de calor críticos em feixes de 5x5 varetas. Observa-se támbém uma boa concordância entre as curvas teóricas previstas por P ANTERA-2 e valores medidos para as velocidades de rotação das bombas e vazões de massa nos circuitos primários da central nuclear Angra-2, quando suas quatro bombas principais são simultaneamente desligadas para simular o evento de declínio de vazão. Palavras-chave: análise por subcanais, código de subcanais, códigos cobra, análise de circuitos de escoamento, acidente de falha de bombas / Abstract: PANTERA-2 (from Programa para Análise Termo-hidráulica de Reatores a ÁguaProgram for Thermal-hydraulic Analysis of Water Reactors, Version 2), whose fundamentals are described in this work, is intended to carry out rod bundle subchannel analysis in conjunction with multiloop simulation. It solves simultaneously the conservation equations of mass, axial and lateral momentum, and energy for subchannel geometry coupled with the balance equations that describe the fluid flows in any number of coolant loops connected to A pressure vessel containing the rod bundle. As far as subchannel analysis is concemed, the basic computational strategy of P ANTERA-2 comes from COBRA codes, but an altemative implicit solution method oriented to the pressure field has been used to solve the finitedifference approximations for the balance laws. The results provided by the subchannel mode1 comprise the fluid density, enthalpy, flow rate, and pressure fields in the subchannels. The loop model predicts the individualloop flows, total flow through the pressure vessel, and pump rotational speeds as a function of time subsequent to the failure of any number of the coolant pumps. The flow transients in the loops may initiated by partial, total or sequentialloss of electric power to the operating pumps. Transient events caused by either shaft break or rotor locking may also be simulated. The changes in rotational speed of the pumps as a function of time are determined from a torque balance. Pump dynamic head and hydraulic torque are calculated as a function of rotational speed and volumetric flow from two polar homologous curves supplied to the code in the tabular form In order to illustrate the analytical capability of P ANTERA-2, three sample problems are presented and discussed. Comparisons between calculated and measured results indicate that the program reproduces with a good accuracy experimental data for subchannel exit temperatures and critical heat fluxes in 5x5 rod bundles. It is also observed a good correspondence between the theoretical curves predicted by P ANTERA-2 and measured values for pump rotational speeds and mass flow rates in the primary loops of Angra-2 nuclear power plant, when the four main coolant pumps are simultaneously switched off to simulate the flow decline evento / Doutorado / Sistemas de Processos Quimicos e Informatica / Doutor em Engenharia Química
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Experimentos de perda de refrigerante total e parcial no reator IEA-R1 / Total and partial loss of coolant experiments in the IEA-R1 reactorEduardo Maprelian 05 June 2018 (has links)
A segurança de instalações nucleares é uma preocupação mundial que tem crescido, sobretudo, após o acidente nuclear de Fukushima. O estudo de acidentes em reatores nucleares de pesquisa tal como o Acidente de Perda de Refrigerante (APR), considerado por muitas vezes um acidente base de projeto, é importante para garantir a integridade da instalação. O APR pode levar ao descobrimento parcial ou total do núcleo do reator e, como condição de segurança, deve-se garantir que haja a remoção do calor de decaimento dos elementos combustíveis. Esse trabalho teve o objetivo de realizar experimentos de descobrimento parcial e total no Elemento Combustível Instrumentado (ECI), construído no Instituto de Pesquisas Energética e Nucleares (IPEN), a fim de estudar os possíveis APRs em reatores de pesquisa. Uma seção de testes, denominada STAR, foi projetada e construída para simular os APRs. O ECI foi irradiado no núcleo do reator IEA-R1 (IPEN) e inserido na STAR, que ficou totalmente imersa na piscina do reator. No ECI, foram instalados termopares para medição das temperaturas do revestimento e do fluido em várias posições axiais e radiais. Foram realizados experimentos para cinco níveis de descobrimento do ECI, um total e quatro parciais, em duas condições distintas de calor de decaimento. Na análise dos resultados, verificou-se que os casos de descobrimento total foram os mais críticos, ou seja, as temperaturas do revestimento foram as maiores quando comparadas com os casos de descobrimentos parciais. Adicionalmente, foi realizada a simulação numérica de dois experimentos com o código RELAP5, cujos resultados demonstraram ótima concordância com os dos níveis experimentais, e temperaturas maiores que as experimentais. As máximas temperaturas do revestimento alcançadas em todos os experimentos ficaram bem abaixo da temperatura de empolamento do combustível, que é de 500°C. Assim, a STAR provou ser um aparato experimental seguro e confiável para a realização de experimentos de perda de refrigerante. / The safety of nuclear facilities has been a growing global concern mainly after the Fukushima nuclear accident. Studies on nuclear research reactor accidents such as the Loss of Coolant Accident (LOCA), considered many times a design basis accident, are important for guaranteeing the integrity of the plant. A LOCA may lead to the partial or complete uncovering of the fuel assemblies and assured decay heat removal is a safety condition. This work aimed to perform partial and complete uncovering experiments in the Instrumented Fuel Assembly (IFA) designed at the Instituto de Pesquisas Energéticas e Nucleares (IPEN) in order to study possible LOCAs in research reactors. A test section for experimental simulation of Loss of Coolant Accident named STAR was designed and built. The IFA was irradiated in the IEA-R1 and installed in the STAR, which was totally immersed in the reactor pool. Thermocouples were installed in the IFA to measure the clad and fluid temperatures in several axial and radial positions. The experiments were carried out for five levels of uncovering of IFA, being one complete uncovering and four partial uncovering, in two different conditions of decay heat. In the results analysis was observed that the cases of complete uncovering of the IFA were the most critical ones, that is, those cases presented higher clad temperatures when compared with partial uncovering cases. Additionally, a numerical simulation of two experiments was carried out by using the RELAP 5 code. The numerical results showed an optimum agreement with the experimental levels results and greater than the experimental temperatures. The maximum clad temperatures reached in all experiments were quite below the fuel blister temperature, which is 500 °C. Therefore, the STAR has proven to be a safe and reliable experimental apparatus for conducting loss of coolant experiments.
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