Submitted by Joana Azevedo (joanad@id.uff.br) on 2017-08-19T18:52:14Z No. of bitstreams: 1 Dissert RICARDO NICOLL JUNIOR.pdf: 3627999 bytes, checksum: 62639dcab37e133915213367543cc1ec (MD5) / Approved for entry into archive by Biblioteca da Escola de Engenharia (bee@ndc.uff.br) on 2017-08-22T16:19:02Z (GMT) No. of bitstreams: 1 Dissert RICARDO NICOLL JUNIOR.pdf: 3627999 bytes, checksum: 62639dcab37e133915213367543cc1ec (MD5) / Made available in DSpace on 2017-08-22T16:19:02Z (GMT). No. of bitstreams: 1 Dissert RICARDO NICOLL JUNIOR.pdf: 3627999 bytes, checksum: 62639dcab37e133915213367543cc1ec (MD5) Previous issue date: 2016-11-25 / Os órgãos reguladores são responsáveis pela regulação em diversos setores da sociedade. No Brasil, atuam em várias áreas para o desenvolvimento do país e têm como objetivo principal o equilíbrio social, econômico e o desenvolvimento nacional. O progresso de novas tecnologias no campo nuclear e sua comercialização acendem a necessidade de uma regulamentação de acordo com padrões de segurança internacionais. A presente pesquisa busca por meio de extensa revisão da literatura, identificar as orientações internacionais para órgãos de regulação e fazer uma análise comparativa entre o Brasil e cinco países que tem organismos regulatórios independentes no setor nuclear. O propósito do trabalho é de contribuir com os setores públicos brasileiros, com uma avaliação da regulação no país na percepção de especialistas e propor diretrizes para a estruturação de um órgão de regulação independente, respeitando acordos internacionais e a legislação vigente no país. / Regulatory bodies are responsible for regulation in various sectors of society. In Brazil, they work in various areas for the development of the country and have as main objective the social, economic and national development. The progress of new technologies in the nuclear field and their commercialization underscores the need for regulation according to international safety standards. The present research searches through an extensive review of the literature identify the international guidelines for regulatory bodies and make a comparative analysis between Brazil and five countries that have independent regulatory bodies in the nuclear sector. The purpose of the work is to contribute to the Brazilian public sectors, with an evaluation of the country's regulation in the perception of specialists and propose guidelines for the structuring of an independent regulatory body, respecting international agreements and the legislation in force in the country.

The Institute of Resource Ecology (IRE) is one of the currently eight institutes of the Helmholtz-Zentrum Dresden-Rossendorf (HZDR). The research activities are fully integrated into the program “Nuclear Safety Research” of the Helmholtz Association and focused on the topics “Safety of Nuclear Waste Disposal” and “Safety Research for Nuclear Reactors”. With the integration of the division of “Reactor Safety” from the former “Institute of Safety Research” nuclear research at HZDR is now mainly concentrated within this institute. In addition, various activities have been started investigating chemical and environmental aspects of processing and recycling of strategic metals, namely rare earth elements. Here, a knowledge transfer from the nuclear to the non-nuclear community, branching thermodynamics and spectroscopy, has been established. This also strengthens links to the recently established “Helmholtz-Institute Freiberg for Resource Technology”.

The Institute of Radiochemistry (IRC) is one of the seven institutes of the Helmholtz-Zentrum Dresden-Rossendorf (HZDR). The research activities are fully integrated into the “Nuclear Safety Research Program” of the Helmholtz Association and focused on the topic “Safety of Nuclear Waste Disposal”. The research objectives are to generate better process understanding and data for the long-term safety analysis of a nuclear waste disposal in the deep geological underground. A better knowledge about the dominating processes essential for radionuclide (actinide) mobilization and immobilization on the molecular level is needed for the assessment of the macroscopic processes which determine the transport and distribution of radioactivity in the environment. Special emphasis is put on the biological mediated transport of long-lived radionuclides in the geosphere and their interaction with different biosystems like biota and human organism for a better calculation of environmental and health risks. Advanced knowledge is needed for description of the processes dominating at the interfaces between geo- and bio-systems related to the distribution of long-lived radionuclides in various bio-systems along the food chain.

The Institute of Safety Research (ISR) is one of the six Research Institutes of Forschungszentrum Dresden-Rossendorf e.V. (FZD), which is a member institution of the Wissenschaftsgemeinschaft Gottfried Wilhelm Leibniz (Leibnizgemeinschaft). Together with the Institutes of Radiochemistry and Radiation Physics, ISR implements the research programme „Nuclear Safety Research“, which is one of the three scientific programmes of FZD. The programme includes two main topics, i. e. “Safety Research for Radioactive Waste Disposal” and “Safety Research for Nuclear Reactors”.

History of peaceful use of nuclear energy, despite of all necessary emphasis on operation safety, is accompanied by a series of accidents, some of which left indelible trace in minds of wide public and so led to changes in the comprehension of nuclear safety and in the access to its preservation. Because the consequences of possible nuclear power plant accident have always serious social impacts, it is most desirable to define all possibly risks, to quantify probability of their formation and in this way to gain the possibility to prevent them effectively and efficiently. This work is dedicated to approve or to disapprove that the KARS method is practically applicable for evaluation of nuclear power station operation safety. The work objective is to evaluate events and risks associated with the operation of a particular nuclear facility by the KARS method and critically evaluate obtained results and the used method as such. The work is divided into theoretical and practical part. Theoretical part includes basic information necessary for correct understanding of the chosen data processing procedure and subsequent interpretation of the gained results. A brief overview of basic concepts relating to the nuclear safety, the safety culture and the emergency preparedness, including their definitions is given in this section of the work. For the evaluation of obtained results it is useful to make familiar with basic concepts of the NPP safety evaluation, PSA and the stress tests. Obviously, it is necessary to describe the KARS method and to define the concept of quality of human performance with regard to the obtained results. The risk analysis by the KARS method was carried out in the four consecutive steps: 1. Data collection for the risk analysis. 2. Data processing by the use of the KARS method. 3. Interpretation of the obtained results. 4. Comparison of the obtained results with the available data. The particular risks for the construction of the risk correlation table were based on the analysis of activities of individual members of the emergency and technical support center on the basis of managing documentation for each function. In the emergency instructions these risks are either named or the action to manage them are determined. Subsequently these risks are further more specify according to the operational documentation used for solving abnormal and emergency conditions or solving of severe accidents. Determination of the risk correlation seems to be subjective and requires a considerable degree of professional insight into the analyzed issues. The risk analysis was processed according to the procedure that was laid down by Ing. Stefan Pacinda, Ph.D. Each risk taken into consideration in this analysis is briefly described within the interpretation of obtained results. The coefficients of activity with the biggest value were found for these risks: human error, earthquake, plane crash, terrorist threat, errors in operating and managing documentation and fire. The coefficients of passivity with the biggest value were found for these risks: human failure, serious damage to health, ecological disaster, components malfunctions, radiation accident, nuclear material integrity damage and control system malfunctions. Comparison of the risks that were postulated in the stress tests and the risks that were considered in this analysis indicate that the ETE NPP emergency response was prepared to be able to cope these risks. Results of this analysis showed that the essential element for the safe operation of nuclear power plants is qualified, well selected and systematically trained staff. In light of the experience acquired during elaboration of this work I have concluded that the KARS method can be used for nuclear safety evaluation only in a limited way.

European and Czech Atomic Law in the Context of Energetic Law and Enviornmental Law (Rennaissance or Declaine) Abstract This dissertation thesis deals with recent developments in atomic law in the Czech Republic, the European Union and in international field. In the Czech Republic, the new Act No. 263/2016 Coll., The Atomic Act, which became a public codex of atomic law, is a legislation that encompasses nuclear safety, radiation protection, radioactive waste management, shipments of nuclear materials and other radioactive sources, security of nuclear materials and nuclear facilities, radiation emergency management, radiation monitoring and non- proliferation of nuclear weapons. Atomic Act replaced the old Act No. 18/1997 Coll. in which only civil liability for nuclear damage remained in force. At European Union level, a serious development can be observed lately, when new directives have been adopted to regulate radioactive waste management, nuclear safety and radiation protection. Recently, the Convention on Supplementary Compensation for Nuclear Damage and the Annex to the Convention on the Physical Protection of Nuclear Material has entered into force internationally. The new Atomic Act attempted to respond to these European and international documents and to implement and transpose their demands into...

Severe accidents arising from the fusion of a nuclear reactor core must be anticipated to enhance the efficiency of their mitigation. Such accidents have occurred at TMI-2 (1979) and Fukushima (2011). Following a loss of coolant accident, core heating and oxidation of the fuel cladding followed by reflooding (injection of water) may lead to the collapse of fuel rods and formation of porous debris bed in the core. Steam produced upon reflooding may activate the exothermic oxidation of Zircaloy leading to partial melting of materials. Such evolution generates zones with reduced porosity limiting coolant penetration and/or impermeable blocked zones. In this situation, the efficiency of injecting water into the core to stop the progress of degradation and prevent the reactor core melting may be significantly reduced. In this scope, IRSN launched PEARL program to investigate the thermal hydraulics of reflooding of hot debris beds surrounded by a more permeable zone simulating the presence of intact or less damaged zones in the core. The PEARL experiments were modeled and simulated using ICARE/CATHARE code to assess the evolution of a bottom reflooding of a superheated debris bed surrounded by a bypass of larger permeability. The thermal hydraulics of the quenching process has been analyzed and the effect of each of the initial conditions on the reflooding behavior was assessed. The effect of pressure was investigated and related to the entrainment of injected water at quench front level into the bypass. An analytical model was then developed to investigate thoroughly the reflooding of a superheated heterogeneous porous medium, composed of two layers of contrasting permeability and porosity, and to describe the water entrainment in the bypass. This model computes the main variables characterizing the reflooding process such as quench front velocity, water-to-steam conversion ratio, and the flow rate of water entrained in the bypass. It provides good qualitative and quantitative results for the two-phase flow redistribution as compared to experimental results. This model has several advantages. It is written in a rather general form including the Forchheimer correction terms and non-zero cross-terms in the generalized Darcy-Forchheimer momentum equation. Variations of proposed momentum equations including changes in correlations andinterfacial friction laws can be tested easily and efficiently. Comparison of the calculations against experimental results indicated that it is necessary to include an interfacial friction law to obtain good predictions. This model allows performing fast evaluations of the efficiency of cooling bycomputing the fraction of the injected flow rate that participates in cooling. Upscaling to the reactor scale is straightforward and calculations were performed to assess the impact of geometric parameters of the debris bed (particle size, porosity, dimensions) as well as thermal hydraulic conditions (temperature, pressure, injection flow rate) on the reflooding process. Thus the model is very useful to estimate the total quenching time and the maximum temperature that could be reached by the hot debris bed at large scales. This allows assessing the probability of a successful quenching of a hot debris bed formed during a hypothetical accidental scenario.

Swedish nuclear power plant control room crews have training sessions in full scope simulators every year. These sessions are designed to prepare operators to cope with incidents and accidents. The aim is to develop operators’ knowledge, skills and abilities necessary to operate the nuclear power plant in a safe manner. Training sessions is an opportunity to practice and develop the crews’ teamwork, decision processes and working strategies. The purpose of this study was to explore if and how the instrument Shared Priorities can support training of nuclear power plant control room crews. Shared Priorities is an instrument to measure teams’ shared awareness of a situation and has in earlier studies been used in military and student teams. During the simulator re-training period of control room crews, 14 crews used the instrument Shared Priorities in one or two of their training scenarios. The instrument consists of two steps. Firstly, crew members generate and prioritise a list of five items they think are most important for the crew to cope with in the scenarios current situation. They also rank another crew member’s list. Secondly, the crews and instructors perform a focus group discussion based on the generated lists. Results from questionnaires, focus group discussions and an interview with instructors showed that operators and instructors believe that Shared Priorities can support their training in several ways. Crews see meetings and other disseminations of information as an essential part of maintaining shared understanding of different situations. They believe the instrument may help crews reflect upon and develop their meeting procedures. Operators and instructors also believe that by using the instrument it can help crews to increase their understanding of having a shared situation understanding and shared vision. However the procedure when using Shared Priorities has to be modified in order to be able to support crews’ training in an optimal way.

The topic of this thesis is Czech nuclear law. The purpose of the nuclear law is to regulate the conditions of use of nuclear energy and ionizing radiation in order to ensure protection of people and environment from the adverse effects of ionizing radiation. Because of highly technical nature of nuclear law, the first chapter is devoted to possibilities of use of ionizing radiation, and to outline few of relevant technical terms. The second chapter of this thesis deals with international cooperation in the area of use of nuclear energy and ionizing radiation. The third and fourth chapters are devoted to Czech nuclear law with main focus on environmental aspects. While the third chapter defines the principles and tools of environmental protection in the field of nuclear law and introduces the structure of legal norms in this area, the fourth chapter analyzes the regulation of specific activities related to the use of ionizing radiation. Included are chapters concerning construction of nuclear facilities, transport of radioactive substances, decommissioning of nuclear facilities and radioactive waste management. Disregarded is neither regulation of liability for nuclear damage. In conclusion, the thesis highlights weak points of the legislation and delineates possible solutions de lege ferenda,...

Cette étude s'inscrit dans le cadre du développement d'outils de simulation de latélémétrie qui est une technique possible pour la surveillance et le contrôle périodique desréacteurs nucléaires à neutrons rapides refroidis par du sodium liquide (RNR-Na).De manière générale, la télémétrie consiste à positionner au sein du réacteur untransducteur qui génère un faisceau ultrasonore. Ce faisceau se propage à travers un milieuinhomogène et aléatoire car le sodium liquide est le siège de fluctuations de température quiimpliquent une variation de la célérité des ondes ultrasonores, ce qui modifie la propagationdu faisceau. Ce dernier interagit ensuite avec une structure immergée dans le réacteur. Lamesure du temps de vol de l’écho reçu par le même transducteur permet de déterminer laposition précise de la structure. La simulation complète de la télémétrie nécessite donc lamodélisation à la fois de la propagation d’une onde acoustique en milieu inhomogènealéatoire et de l’interaction de cette onde avec des cibles de formes variées ; c'est l'objectif dece travail.Un modèle stochastique basé sur un algorithme de type Monte-Carlo est tout d'aborddéveloppé afin de simuler les perturbations aléatoires du champ de propagation. Le champacoustique en milieu inhomogène est finalement modélisé à partir du champ calculé dans unmilieu homogène moyen en modifiant les temps de parcours des rayons homogènes parincorporation d’une correction fournie par le modèle stochastique. Le modèle stochastiquede propagation ainsi développé a été validé par comparaison avec un modèle déterministe ets’avère nettement plus simple à mettre en oeuvre au sein de la plateforme logicielle desimulation en contrôle non destructif CIVA et moins couteux en temps de calcul que lemodèle déterministe.En vue de modéliser l’interaction onde acoustique/cible, des modèles classiques dediffraction ont été évalués dans le cadre de structures rigides, parmi lesquels la théoriegéométrique de la diffraction (GTD) et l’approximation de Kirchhoff (KA), ces deuxapproches apparaissant comme complémentaires. En les combinant de sorte à ne conserverque leurs avantages, nous avons développé un modèle hybride (KA raffiné) en utilisant uneprocédure similaire à la théorie physique de la diffraction (PTD). Le modèle KA raffinéfournit une amélioration de la prédiction en champ proche d’une cible rigide. Le modèle dediffraction KA initial (non raffiné) a été ensuite étendu pour traiter une cible réalisted’impédance finie. Le modèle KA « général » ainsi obtenu se révèle être une solutionsatisfaisante pour l’application à la télémétrie. Finalement, le couplage du modèlestochastique de propagation et du modèle de diffraction KA général nous a permis deconstruire un outil de simulation complète de la télémétrie en milieu inhomogène. / This study takes place in the framework of tools development for thetelemetry simulation. Telemetry is a possible technology applied to monitoring the sodiumcooledfast reactors (SFR) and consists in positioning in the reactor core a transducer togenerate an ultrasonic beam. This beam propagates through an inhomogeneous randommedium since temperature fluctuations occur in the liquid sodium and consequently thesound velocity fluctuates as well, which modifies the bream propagation. Then the beaminteracts with a reactor structure immersed in sodium. By measuring the time of flight of thebackscattered echo received by the same transducer, one can determine the preciselocation of the structure. The telemetry simulation therefore requires modeling of both theacoustic wave propagation in an inhomogeneous random medium and the interaction of thiswave with structures of various shapes; this is the objective of this work.A stochastic model based on a Monte Carlo algorithm is developed in order to take intoaccount the random fluctuations of the acoustic field. The acoustic field through aninhomogeneous random medium is finally modeled from the field calculated in a meanhomogeneous medium by modifying the travel times of rays in the homogeneous medium,using a correction provided by the stochastic model. This stochastic propagation model hasbeen validated by comparison with a deterministic model and is much simpler to integrate inthe CIVA software platform for non destructive evaluation simulation and less timeconsuming than the deterministic model.In order to model the interaction between the acoustic wave and the immersedstructures, classical diffraction models have been evaluated for rigid structures, including thegeometrical theory of diffraction (GTD) and the Kirchhoff approximation (KA). These twoapproaches appear to be complementary. Combining them so as to retain only theiradvantages, we have developed a hybrid model (the so-called refined KA) using a proceduresimilar to the physical theory of diffraction (PTD). The refined KA provides an improvementof the prediction in the near field of a rigid scatterer. The initial (non refined) KA model isthen extended to deal with the scattering from a finite impedance target. The obtainedmodel, the so-called “general” KA model, is a satisfactory solution for the application totelemetry. Finally, the coupling of the stochastic propagation model and the general KAdiffraction model has allowed us to build a complete simulation tool for the telemetry in aninhomogeneous medium.