In accident analysis regarding nuclear power plants, it is very common to use thermal hydraulic system codes, such as TRACE, developed by U.S. NRC. In the case of licensing a power plant, this is one of the necessities. TRACE is a relatively new thermal hydraulic system code and a lot of knowledge is needed to implement it in a correct way, especially in accident analysis, where it is a requirement that the rules and statements in Appendix-K, dealing with criteria for ECCS-models, are modelled. In this thesis an improved model of a Swedish Boiling Water Reactor within TRACE is realized and tested. Afterwards, once a working and representative model has been obtained, a sensitivity study in conducted in order to investigate the sensitivity of TRACE for a couple of thermal hydraulic parameters. The sensitivity study is focussing on the eect of the peak cladding temperature, as well as the coolability of the nuclear fuel in terms of quenching and quench-front velocities. It is found to be hard to say unilaterally what the eect of changing a certain number of parameters on the reactor behaviour is. As it turns out to be, although strongly related, the peak cladding temperatures and the quench phenomena can behave dierently

The master´s thesis entitled The issue of obstacles on roads deals with the analysis of accidents with a obstacle in a selected area in the Czech Republic. The main purpose of the master´s thesis is to find out the details of the occurrence of traffic accidents with a obstacle and their other properties (type of obstacle, accident time, climatic conditions etc.).

This paper sets out to identify skills required by cyclists to navigate safely through an urban environment in Switzerland. We set out to identify situations that might result in accidents and require specific competences. Three study studies were conducted First, workshops with experts were conducted to identify required cyclists' skills. Second, accident statistics were analysed to determine in which type of situations accidents occur. Finally, a survey was conducted among Swiss cyclists to assess which skills were present and which skills were lacking. The remainder of this extended abstract describes the three studies in some detail and continues with an outlook for the final paper. [from Introduction]

A high percentage of highway crashes in the United States occur at intersections. These crashes result in property damage, lost productivity, injury, and even death. Identifying intersections associated with high crash rate is very important to minimize future crashes. The purpose of this study is to develop efficient means to evaluate intersections, which may require safety improvements. The area covered by the analysis in this thesis includes Orange and Seminole Counties and the City of Orlando. The aforementioned counties and city thus represent Central Florida. Each County/City provided data that consisted of signalized intersection drawings that were either in the form of electronic or hard copies, the county's extensive crash database and a list of intersections that underwent modifications during the study period. A total of 786 intersections were used in the analysis and the crash database was made up of 4271 crashes. From the signalized intersection drawings obtained from the county's traffic engineering department, a geometry database was created to classify all intersections by the number of through lanes, number of left turning lanes, Average Annual Daily Traffic and Posted Speed limits on the Major road of the intersection. In this research, crashes and their type, e.g., rear-end, left-turn and angle as well as total crashes were investigated. Numerous models were developed first using the Poisson regression and then using the Negative Binomial approach as the data showed overdispersion. The modeling process aimed to relate geometric and traffic factors to the frequency of crashes at intersections. Expected value analysis tables were also developed to determine if an intersection had an abnormally high number of crashes. These tables can be used in assisting Traffic Engineers in identifying serious safety problems at intersections. The general models illustrated that rear-end crashes were associated with high natural logarithm of AADT on the major road and the number of lanes (major intersections, e.g. 6x4/6x6), whereas AADT on the major road did not affect left-turn crashes. Intersections with the configuration 4x2/6x2 (2 through lanes at the minor roadway) or T intersections as another category experienced an increase in left-turn crashes. Angle crashes were most frequent at one-way intersections especially in the case of 4x4 intersections. Individual models that included interaction terms with one variable at a time concluded that AADT on the major road positively influenced rear-end crashes more compared to angle and left-turn crashes. As the speed increases on the minor road, the left turn crashes are affected more when compared to angle and rear-end crashes, therefore it can be concluded that left-turn crashes are most influenced by the speed limit on the minor road compared to angle crashes and then followed by rear-end crashes. As the total number of left turn lanes increased at the intersection, thereby increasing the size of the intersection, the number of rear-end crashes increased. An overall model that contained natural logarithm of AADT on major road, total number of left turn lanes at the intersection, number of through lanes on the minor road and configuration of the intersection, as independent variables, along with interaction terms, further concluded and supported the individual models that the number of crashes (rear-end, left-turn and angle) increased as the AADT on the major road increased and the number of crashes decreased as the total number of left turn lanes at the intersection increased. Also, crashes increased as the number of through lanes on the minor road increased. The variables' interaction effects with dummies representing rear-end and left-turn crashes in the final model showed that as the AADT on the major road increased, the number of rear-end crashes increased compared to left-turn and angle crashes and also that as the total number of left turn lanes at the intersection increased, the number of left-turn crashes decreased when compared to rear-end and angle crashes. Also the number of rear-end crashes increased at major four leg intersections e.g. 6x4, 6x6 etc. This thesis demonstrated the superiority of Negative Binomial regression in modeling the frequency of crashes at signalized intersections.

In the recent years, pedelecs (pedal electric cycles) have seen a massive growth. in ridership. In 2013, around 1.3 million e-bilces were on German roads, while in 2020, this number was already at 8.5 million (with about 99% of the e-bikes being pedelecs). The rapid spread of pedelecs has given rise to concerns for road safety, especially due to the fact that riders of electric bicycles reach higher speeds. Indeed, some studies have reported that pedelec riders suffer from more severe crashes than users of conventional bikes. However, the highly dynamic development in pedelec ownership and use might cast some doubts on the long term validity of investigations of pedelec accidents and their characteristics that have to rely on data collected over shorter periods of time. Therefore, the aim of this study was to investigate pedelec accidents and their characterutics over several years in a longitudinal fashion. and compare them to accidents involving cyclists, tobe able to identify trends, and to clarify whether such trends are specifiic to pedelecs. [From: Introduction]

Approved for public release, distribution is unlimited / 235 Class A Navy and Marine (Naval) aviation mishaps involving aircrew error between FY 90 and FY 98 are analyzed for the possibility of being weather related. In addition to determining the overall role of weather, weather related mishaps are compared to aircraft category, mishap characteristic, the Naval Safety Center human factors (HFACS) taxonomy, and flight phase. In addition, weather related mishap trends have been analyzed. Results show 19% of mishaps involving aircrew error are weather related with helicopter category and controlled flight into terrain (CFIT) mishap characteristic having the largest percent of weather related mishaps for their respective groupings. Visibility related weather elements account for over half of all weather related mishaps, and nearly two-thirds of all weather related mishaps were judged to be preventable with a perfect weather forecast believed by aircrew. These and other findings are presented to develop intervention strategies for reducing the number of weather related flight mishaps (FMs) per year. / Lieutenant Commander, United States Navy

Introdução - Os acidentes de trabalho na construção civil são considerados como graves problemas de saúde pública devido ao grande número de riscos ocupacionais que seus trabalhadores estão expostos. Esses acidentes implicam em elevados custos, e geralmente são analisados por teorias unicausais, as quais limitam a prevenção de acidentes semelhantes, sendo importante um estudo mais ampliado baseado em teorias organizacionais e sistêmicas. Objetivo - Contribuir para o aprimoramento das metodologias de análise de acidente, integrando abordagem organizacional com a teoria do aprendizado expansivo potencializando o protagonismo interno nas organizações. Método - Coleta de dados etnográficos, como entrevistas, observações em situação e análise de documentos referente à obra de construção do aeroporto. Foram entrevistados trabalhadores de diferentes funções e departamentos da empresa, como também duas sessões de Análise Coletiva do Trabalho. Aplicação do Modelo de Análise e Prevenção de Acidentes de Trabalho (MAPA) juntamente com o Modelo de Análise Organizacional do Evento (AOE), que propõem uma abordagem sistêmica do caso foram utilizados, juntamente com os outros dados, como suporte para as sessões do Laboratório de Mudanças (LM). Estas sessões foram planejadas com base na teoria do aprendizado expansivo e no conceito da dupla estimulação. Resultados - A análise do trabalho habitual, da análise de mudanças e de barreiras e da dimensão histórica, vertical e transversal permitiram compreender as causas latentes do acidente, que teve origem em rede de múltiplas falhas em interação (gestão de projeto e de mudanças; gestão de materiais e logística; gestão de terceiras; gestão de emergências; gestão de segurança). A análise histórica mostrou que estes fatores emergiram ao longo do tempo na organização como fruto de decisões gerenciais em diferentes níveis. O aeroporto foi planejado para ser construído em tempo determinado politicamente, e insuficiente e incompatível com a sua complexidade. A escolha da modalidade de contrato em que o consórcio era responsável por todas as fases da obra, foi outro evento histórico crítico, pois permitiu que a obra iniciasse sem o projeto executivo definitivo. Além disso, havia diferentes culturas de empresas trabalhando juntas pela primeira vez em contexto de pressão temporal, com a utilização de terceirização de atividades sem a coordenação necessária. Estas mudanças levaram a manifestações de contradições secundárias, que acabaram levando ao surgimento de anomalias, tais como, retrabalho, acidentes, atrasos, desperdício de recursos. Muitos problemas relativos à construção do aeroporto apareceram nas sessões do LM. O método da dupla estimulação propiciou o engajamento dos atores com a criação de artefatos e modelos, tais como, linha do tempo da obra, círculo vicioso, sistema de atividade que contribuíram para uma visão mais expansiva das contradições que estavam levando a anomalias na obra e criação de possíveis soluções. Conclusão - A metodologia do LM e o uso dos conceitos de aprendizagem expansiva, associados aos conceitos usados no MAPA e na AOE possibilitaram a compreensão das manifestações de contradições e origens sistêmicas do acidente e de outras anomalias na obra, a criação de agência (protagonismo) e o engajamento dos atores bem como, a visualização de soluções preventivas em obras futuras. / Introduction - Work accidents in construction are serious problems at public health due to the large number of occupational risks that their workers are exposed. These accidents involve high costs, and are generally analyzed by unicausal theories, which limit the prevention of similar accidents. It is important a broader study based on organizational and systemic theories. Aim - Contribute at improving the accident analysis methodologies, integrating organizational approach to the theory of expansive learning enhancing the agency inside the organizations. Method Ethnographic data collection such as interviews, observations and analysis of documents related to the airport construction. Workers of different functions and departments of the company were interviewed, as well two sessions of Collective Worker Analysis was applied. Application of Model of Analysis and Prevention of Work Accident (MAPA) along with the Model of Event Organizational Analysis (AOE), which propose a systemic approach to the case. These analysis were used to support the sessions of the Changes Laboratory (CL) which were based on theory of expansive learning and the concept of double stimulation. Results - The analysis of habitual work, the analysis of changes and barriers and analysis of historical, vertical and transverse dimension allowed to understand the accident underlying causes, which was originated in the network of multiple failures in interaction (management of projects and changes; management of materials and logistics; management of outsourcing companies; management of emergencies; safety management). The historical analysis showed that these factors had emerged over time at organization as a result of management decisions at different levels. The airport was planned to be built in time determined politically, and insufficient and inconsistent with its complexity. The choice of the type of contract, which the consortium was responsible for all phases of the construction site, was another critical historical event because it allowed the airport construction initiated without the definitive executive project. Moreover, there were different cultures of companies working for the first time together in time pressure context, with the outsourcing strategy without the necessary coordination. These changes have led to manifestations of secondary contradictions, which eventually led to the emergence of anomalies, such as rework, accidents, delays, waste of resources. Many problems concerning the construction of the airport appeared during CL sessions. The method of double stimulation led to the engagement of actors with the creation of artifacts and models, such as timeline of the construction site, vicious circle and activity system, which contributed to an expansive view of contradictions that were leading to anomalies in this site and creation of possible solutions. Conclusion - The CL and concepts of expansive learning associated with the concepts used at MAPA and AOE provided an understanding of the manifestations of contradictions and systemic origins of the accident and other anomalies at airport construction site; criation of agency and engagement of actors; and also at visualizing preventive solutions in future construction sites.

Explaining incidents as systems is a fast growing area of safety scientific research. The misleading conception of naturalistic human communication in terms of 'objective information' remains a pervasive influence on systemic explanation of incidents, despite over a decade of methodological developments in the area. Currently, interested stakeholders are offered with few alternatives for analysing how information systems emerge naturally, and contribute towards the structuring of incident situations. Extant methods are also yet to be widely adopted by the practitioner community, and a research-practice gap has formed. In this PhD research, a new method of systemic incident analysis is developed, to counterbalance against the extant methods being developed in the area. The new method draws on insights from both Distributed Cognition, and linguistics research, in order to present a distributed means of doing systemic incident analysis. The new method de-objectifies the notion of information, to support analysis of how information 'flow' is constitutive of the formation of distributed cognitive systems. In embedding an intersubjective component into the core method design, we aim to increase the likelihood of systematic learning from incident situations. The incident analyst is required to explicitly relate past explanations of incident situations, in detail, to data and hypotheses from new incident situations. To increase the potential for theorists in the area to better account for the demands of incident analysis as practiced, data, insights, and method are contributed towards the bridges been built between research and practice. We first develop additional understanding of the practice of incident analysts from the patient safety background. Next, we provide a second new method of analysis, to allow research scrutiny of the empirical phenomena of using systemic incident analysis methods. This second method considers the detailed relationship: from the theory of the systemic incident analysis method into its practice as part of real incident investigation. This provides a new research instrument, for systematically examining how systemic incident analysis methods may afford or constrain elements of their practice.

Objetivos. Analisar investigações de acidentes e materiais didáticos e educativos, explorando aspectos da construção das análises e de atribuição de culpa. Métodos. Registros de investigações e materiais didáticos de empresas de Botucatu-SP, em 1997, obtidos de instituições e empresas, foram analisados, identificando-se fatores causais, recomendações e referências a comportamentos faltosos ou características da vítima. Árvores de causas foram checadas quanto a cuidados de linguagem, desenhos, interrupções da investigação, tipos de relações entre fatos e exploração para prevenção. Materiais educativos foram analisados, identificando-se concepções de acidente, orientações para investigações e recomendações. Bancos de dados foram formados e gerenciados com EPIinfo. Resultados. Foram analisadas 203 investigações. A média de “causas" por AT foi 1,68 e a de recomendações foi 1,4 por AT, com predomínio de referências a comportamentos ou características da vítima. A maioria das análises baseava-se em formulário obrigatório. Todas as árvores analisadas mostravam desrespeito flagrante a regras e princípios do método. Materiais didáticos veiculavam mesma concepção de acidente das investigações, método de análise centrado em comportamentos faltosos do operador, estímulo ao medo de lesões e recomendações para obediência a regras e uso de equipamentos de proteção. Conclusão. As investigações adotam concepção de acidente baseada na identificação de situações de desrespeito a regras idealizadas, atribuem culpa ao acidentado e não subsidiam a gestão de riscos nas empresas. A atribuição de culpa ocorre independentemente da natureza e/ou tipo de perigo presente nos acidentes. Tentativas de uso do método de árvore de causas mostraram distorções, revelando insuficiência no seu domínio. A construção da culpa foi reforçada por materiais didáticos e educativos. Descritores: Acidentes do trabalho, investigações de acidentes, vigilância de acidentes. / Objectives: To analyze accident investigations and teaching and educational materials exploring aspects of analysis construction and blame attribution. Methods: Investigation reports and educational materials of companies in Botucatu, SP, in 1997, obtained from institutions and companies were analyzed and causal factors, recommendations and references to faulty behavior or victim characteristics were identified. Causal tree were checked in regard to language, design, investigation interruptions, types of relations between facts and exploration for prevention. Educational materials were analyzed identifying the conception of accident, orientation for investigations and recommendation. Data banks were formed and managed by EPIinfo. Results: 203 investigations with an average of 1,68 causes and 1,4 recommendations were analyzed and revealed that references to victim’s behavior or characteristics prevailed. Most analyses were based on an obligatory form. All analyzed trees showed evident disrespect to rules and methodological principles. The educational and teaching materials convey the same accident concept as the investigations, the analyses method centered in the faulty behavior of the operator, stimulus of fear to injury and recommendation for obedience to rules and use of protection equipment. Conclusion: The investigations studied use an accident concept based on the identification of situations of disrespect to idealized rules, blame the injured subjects, and do not support the risk management in the companies. The blame bias occurs independently of the nature or kind of danger involved in the accidents. The attempts to use the causal tree method revealed distortions due to insufficient command. Educational materials strengthened the construction of blame.

Objetivos. Analisar investigações de acidentes e materiais didáticos e educativos, explorando aspectos da construção das análises e de atribuição de culpa. Métodos. Registros de investigações e materiais didáticos de empresas de Botucatu-SP, em 1997, obtidos de instituições e empresas, foram analisados, identificando-se fatores causais, recomendações e referências a comportamentos faltosos ou características da vítima. Árvores de causas foram checadas quanto a cuidados de linguagem, desenhos, interrupções da investigação, tipos de relações entre fatos e exploração para prevenção. Materiais educativos foram analisados, identificando-se concepções de acidente, orientações para investigações e recomendações. Bancos de dados foram formados e gerenciados com EPIinfo. Resultados. Foram analisadas 203 investigações. A média de “causas” por AT foi 1,68 e a de recomendações foi 1,4 por AT, com predomínio de referências a comportamentos ou características da vítima. A maioria das análises baseava-se em formulário obrigatório. Todas as árvores analisadas mostravam desrespeito flagrante a regras e princípios do método. Materiais didáticos veiculavam mesma concepção de acidente das investigações, método de análise centrado em comportamentos faltosos do operador, estímulo ao medo de lesões e recomendações para obediência a regras e uso de equipamentos de proteção. Conclusão. As investigações adotam concepção de acidente baseada na identificação de situações de desrespeito a regras idealizadas, atribuem culpa ao acidentado e não subsidiam a gestão de riscos nas empresas. A atribuição de culpa ocorre independentemente da natureza e/ou tipo de perigo presente nos acidentes. Tentativas de uso do método de árvore de causas mostraram distorções, revelando insuficiência no seu domínio. A construção da culpa foi reforçada por materiais didáticos e educativos. Descritores: Acidentes do trabalho, investigações de acidentes, vigilância de acidentes. / Objectives: To analyze accident investigations and teaching and educational materials exploring aspects of analysis construction and blame attribution. Methods: Investigation reports and educational materials of companies in Botucatu, SP, in 1997, obtained from institutions and companies were analyzed and causal factors, recommendations and references to faulty behavior or victim characteristics were identified. Causal tree were checked in regard to language, design, investigation interruptions, types of relations between facts and exploration for prevention. Educational materials were analyzed identifying the conception of accident, orientation for investigations and recommendation. Data banks were formed and managed by EPIinfo. Results: 203 investigations with an average of 1,68 causes and 1,4 recommendations were analyzed and revealed that references to victim’s behavior or characteristics prevailed. Most analyses were based on an obligatory form. All analyzed trees showed evident disrespect to rules and methodological principles. The educational and teaching materials convey the same accident concept as the investigations, the analyses method centered in the faulty behavior of the operator, stimulus of fear to injury and recommendation for obedience to rules and use of protection equipment. Conclusion: The investigations studied use an accident concept based on the identification of situations of disrespect to idealized rules, blame the injured subjects, and do not support the risk management in the companies. The blame bias occurs independently of the nature or kind of danger involved in the accidents. The attempts to use the causal tree method revealed distortions due to insufficient command. Educational materials strengthened the construction of blame.