Thesis (M. Phil.)--University of Hong Kong, 2006. / Title proper from title frame. Also available in printed format.

published_or_final_version / abstract / Physics / Master / Master of Philosophy

This paper examines the history of nuclear energy, safety developments of reactors and nuclear energy policy from the 1950s on. I investigate the effects of nuclear accidents on energy policy with the help of a panel dataset of 31 countries from 1965-2009, using annual data about the capacity of reactors under construction, primary energy consumption, as well as three nuclear accidents scaled INES five or higher by the International Atomic Energy Agency. After determining the extent of the accident impact in the different countries, I find that neither Three Mile Island nor Lucens had a worldwide negative effect on construction starts, while Chernobyl did. The effect of Chernobyl is however shown to wear-off in certain geographical clusters, after ten to thirty years. I find that nuclear capacity enlargement shows a significant persistence, but it was also driven by primary energy consumption in the past five decades. The effects of real interest rates, inflation, or gross domestic product on reactor construction were not found significant. Thus, an accident is likely to have a negative and long lasting impact in the country where it happened, and possibly in countries affected by the direct consequences, or where governments are subject to severe public pressure.It is difficult to estimate the consequences Fukushima is going to have on worldwide power plant constructions, but areas closer to the accident might be affected more negatively and for a longer time. Growing concerns of energy supply security and greenhouse gas emissions may counteract this impact at the legislative level. (author's abstract) / Series: Department of Economics Working Paper Series

Thesis (M. S.)--Mechanical Engineering, Georgia Institute of Technology, 2008. / Committee Chair: Willem F.G. Van Rooijen; Committee Member: Ghiaasiaan, Seyed M; Committee Member: Weston M. Stacey

Cette thèse étudie le rôle des coûts de construction et de réglementation de la sécurité sur la compétitivité de l'énergie nucléaire. L'analyse des coûts de construction est basée sur l'utilisation de données réelles provenant des parcs nucléaires français et américains. En particulier, nous étudions différents canaux à partir de laquelle des réductions de coûts pourraient survenir. Nous montrons que la normalisation est un critère crucial pour la compétitivité économique de l'énergie nucléaire, d'abord parce que les effets d'apprentissage positifs sont conditionnels à la technologie, ce qui signifie que les réductions de coûts ne peuvent venir que si le même type de réacteur est construit à plusieurs reprises, mais aussi parce qu'elle permet de réduire le coût indirectement par l'intermédiaire de courts délais de construction. Dans l'analyse du rôle de réglementation de la sécurité, nous évaluons d'abord l'effet du dernier accident nucléaire majeur (c.-à Fukushima Dai-ichi) de la probabilité de survenance d'un tel événement, puis les effets de l'incertitude concernant la façon dont les soins de la sécurité à réduire la probabilité d'un accident nucléaire dans l'établissement de normes de sécurité en vertu de l'aléa moral et responsabilité limitée. Nous constatons que la norme sera la moins stricte lorsque le régulateur adopte une approche pire des cas, et plus stricte lorsque le régulateur adopte l'approche de la robustesse de regret et il est optimiste quant à l'efficacité des soins de la sécurité pour réduire le risque d'accident. Toutefois, cette norme pourrait induire le non-respect par les opérateurs les moins efficaces. / This thesis studies the role of construction costs and safety regulation on nuclear power competitiveness. The analysis of the construction costs is based on the use of the actual data coming from the american and french nuclear fleet. In particular, we study different channels from which cost reductions might arise. We show that standardization is a key criterion for the economic competitiveness of nuclear power, first because the positive learning effects are conditional to the technology, this means that cost reductions will arise only if the same type of reactor is built several times, but also because it allows to reduce the cost indirectly through shorter construction lead-times. In the analysis of the role of safety regulation, we first asses the effect of the latest major nuclear accident (i.e Fukushima Dai-ichi) in the probability of occurrence of such an event and then the effects of the uncertainty regarding how safety care reduce the probability of a nuclear accident in setting safety standards under moral hazard and limited liability. We find that the standard will be stricter when the regulator is optimistic in the safety care effectiveness to reduce the risk of an accident, but simultaneously this policy might induce no compliance of the most inefficient operators.

L’évaluation des risques, en situation d’urgence nucléaire, est entachée d’incertitudes sur le transfert de substances radioactives dans les écosystèmes terrestres et vers l’homme à travers la chaîne alimentaire pouvant altérer les décisions. L’ampleur des répercutions des accidents de Tchernobyl et de Fukushima a mis en évidence la difficulté de gérer les conséquences post-accidentelles de tels événements et d’appréhender les incertitudes dans les prises de décision. L’objectif de cette thèse est de développer une méthodologie pour la prise en compte des incertitudes dans les modèles d’évaluation de risque environnemental et alimentaire afin d’améliorer les outils d’aide à la décision en situation accidentelle. Différents modèles bayésiens hiérarchiques visant à saisir, dans un cadre unique de modélisation, l’incertitude et la variabilité sur des paramètres radioécologiques d’intérêt en situation post-accidentelle ont été développés. Les paramètres de ces modèles ont été estimés par inférence bayésienne sur des données collectées à partir d’une revue étendue de la littérature. L’influence sur les modèles d’évaluation de risque, des incertitudes autour de ces paramètres radioécologiques, a été évaluée par simulations probabilistes et analyses de sensibilité, appliquées à deux cas d’études : un accident hypothétique et l’accident de Fukushima. Les travaux réalisés dans cette thèse contribuent à améliorer la connaissance autour des processus clés de transfert de radionucléides dans l’environnement et la paramétrisation des modèles radioécologiques d’évaluation de risque en ligne avec les axes de recherche prioritaires définis par la communauté scientifique en radioécologie. / Risk assessment, in case of nuclear emergency, is confronted to uncertainties on the transfer of radioactive substances in terrestrial ecosystems and to human population through the food chain, which could affect the reliability of decisions. The extent of the repercussions of Chernobyl and Fukushima accidents highlighted the difficulty of managing the consequences of such disasters and specifically to accommodate the different sources of uncertainty within decision-making processes. The objective of this research is to develop a methodology to account for uncertainties within environmental and food risk assessment models to improve decision support tools used for accidental situations. Different hierarchical Bayesian models aiming at capturing, within a unique modelling framework, uncertainty and variability about radioecological parameters of great importance for accidental situation were developed. Models parameters were estimated by Bayesian inference applied on databases obtained by an extended literature review. The impact on the risk assessment models of uncertainties about these radioecological parameters was then assessed by stochastic simulations and sensitivity analyses applied on two case-studies: a hypothetical accident simulating a standardized deposition of radionuclides and the accident of Fukushima nuclear power plant. The works developed in this project contribute to enhance knowledge on key processes governing environmental transfer of radionuclides and to improve the parameterization of the radioecological risk assessment models with respect to the research lines outlined by the scientific community in radioecology.

L’étude de l’évolution du droit international face aux risques posés par les accidents nucléaires soulève une série de questionnements. Le premier est relatif aux moyens juridiques par lesquels le droit entend faire face aux risques et à leur matérialisation. Le second va s’attacher à apprécier l’efficacité et l’effectivité du droit adopté. Enfin, en postulant d’un relatif échec du droit suite à la survenance des accidents nucléaires, il faut encore s’interroger sur les possibilités d’amélioration du droit. Ces différentes interrogations peuvent être rassemblées sous la question plus générale de la pertinence de l’adaptation du droit international face au risque nucléaire. Plus largement, la thèse qui émane de ces travaux est celle d’une adaptation continue du droit, issue de la dynamique dialogique existant entre la science juridique et le progrès scientifique, comme un gage d’une amélioration de son efficacité et de son effectivité. Cette adaptation est toutefois dépendante de l’évolution technique de l’énergie nucléaire. En effet, l’atome va à la fois limiter et étendre la portée même de ce droit. Cette caractéristique originale, laisse entrevoir la présence de difficultés au sein de l’ambitieuse mission consistant à appréhender le fait scientifique dans toute sa complexité. L’enjeu est de taille pour le droit nucléaire international : il s’agit de pallier les effets d’un risque technologique majeur afin de préserver les conditions de vie de l’humanité / Reviewing the complex relation between international law and nuclear risks posed by major accidents raises a set of questions. It first addresses the nature of the legal response made in this regard. It also appreciates whether the framework is sufficiently efficient and effective. At last, assuming that nuclear accidents turn international law into a relative failure, it is worth exploring different means to enhance the said law. Simply put, this brings us to the question of whether the adaptation of international law to nuclear risk is relevant. More broadly, our thesis consists in defending that continuous adaptation of law, resulting from the dynamic dialogue between legal science and scientific progress, improves its efficiency and effectiveness. However, the adaptation widely depends on the technological development of nuclear energy, as the atom both limits and extends the scope of international law. This original feature reveals that many difficulties arise when it comes to grasp the complexity of scientific facts. The stakes are high as international nuclear aims at mitigating the effects of a major technological risk in order to preserve the living conditions of mankind

Energy production systems are essential for human progress. They fuel the technologies that underpin economic growth and are prerequisite for efficient food production, education and healthcare. On the flip side, they also incur substantial eco-social costs. Hence, finding and promoting sustainable means of energy production is a key topic within the Environmental Sciences. This thesis examines the sustainability of nuclear power, by comparing its social, economic and ecological impacts to those of wind and solar power. The assessment is performed using Multi-Criteria Analysis (MCA), with a Weighted Sum scoring system and a Distance-To-Target weighting scheme. The selection and the weighting of the indicators are grounded in the Planetary Boundaries framework, the Oxfam Doughnut Economics model and the UN’s Sustainable Development Goals, and the technologies are compared on 9 axes of evaluation; greenhouse gas emissions, land-take requirements, material throughput, non-recyclable wastes, toxic and radioactive wastes, negative health impacts, economic costs, intermittency and energy return on energy invested. The thesis finds nuclear power to be the most sustainable option according to all but three indicators, and in the unified analysis, it outcompetes wind and solar by a factor of 2 and 3 respectively. Also notable is that solar power does not excel in a single impact category; it has the highest greenhouse gas emissions, the largest land-take, and it is costly, intermittent and energy-inefficient. It is also a source of toxic pollution, the effects of which cannot yet be determined. Although wind is more competitive, it consumes vast amounts of physical resources, generates a lot of waste, and its land-take is at least 10 times higher than that of nuclear power. In addition to the MCA, the thesis investigates three perceived threats that are often raised in criticisms of nuclear power; the risk of nuclear fuel depletion, the risk of nuclear weapons proliferation and the risk of catastrophic nuclear accidents. The results show that many popular arguments against the technology are loosely aligned with reality, and the thesis as a whole presents a challenge to the notion that nuclear power is a dangerous and unsustainable energy source.

As the United States expands its quantity of nuclear reactors in the near future, the amount of spent nuclear fuel (SNF) will also increase. Closing the nuclear fuel cycle has become the next major technical challenge for the nuclear energy industry. By separating the transuranics (TRU) from the SNF discharged by Light Water Reactors, it is possible to fuel Advanced Burner Reactors to minimize the amount of SNF that must be stored in High Level Waste Repositories. One such ABR concept is the Subcritical Advanced Burner Reactor (SABR) being developed at the Georgia Institute of Technology. SABR is a subcritical, sodium-cooled fast reactor with a fusion neutron source capable of burning up to 25% of the TRU fuel over an 8.2 year residence time. In the SABR concept an annular core with a thickness of 0.6 m and an active height of 3.2 m surrounds the toroidal fusion neutron source. Neutron multiplication varies during the lifetime of the reactor from keff = 0.95 at the beginning of reactor life to 0.83 at the end of an equilibrium fuel cycle. Sixteen control rods worth 9$ are symmetrically positioned around the reactor. This thesis describes the dynamic safety analysis of the coupled neutron source, reactor core and reactor heat removal systems. A special purpose simulation model was written to predict steady-state conditions and accident scenarios in SABR by calculating the coupled evolution of the power output from the fusion and fission cores and the axial and radial temperature distributions of a fuel pin in the reactor. Reactivity Feedback was modeled for Doppler and sodium coolant voiding. SABR has a positive temperature reactivity feedback coefficient. A series of accident scenarios were simulated to determine how much time exists to implement corrective measures during an accident before damage to the reactor occurs.

This diploma thesis on the application of logical, empirical and statistical methods defined the role of the complementarity principle in the preparation of experts in the field of the protection of population in the framework of a quantitative research. The complementarity principle is characterized in the thesis in general (working with two expressions, both of them are necessary to explain the nature of the problem but cannot be used simultaneously, e.g. expressions "analysis" and "synthesis"). The diploma thesis then defined the physical aspect of the complementarity principle the wave-corpuscular dualism, the position and the momentum, the energy and the time. The comparison of the basics of the protection of population with the structure of the physical aspect of the complementarity principle followed. The performed comparison was adjusted to the needs and possibilities of future experts in the field of the protection of population on the basis of the theory of the curriculum process. The steps are clear from the set of objectives which were fulfilled gradually in the thesis: 1) To systematically describe the general form of the complementarity principle and its physical application from the point of view of the theory of the curriculum process. 2) To create a structure of the system of emergencies from the point of view of a scientific field of the protection of population and to focus on its educational aspect for the preparation of experts. 3) To perform the comparison of the physical aspect and emergencies with the general form of the complementarity principle. To transfer the findings, a theory of curriculum process was used. The link between a more generally approached complementarity principle and the protection of population was explained in the framework of a conceptual curriculum. The theory connecting these two different fields is the more generally approached complementarity principle and especially Bohr's complementarity principle linking not only the wave-corpuscular dualism but also Heisenberg's uncertainty principle. The physical aspect of emergencies was adjusted to the possibilities and needs of students (the intended curriculum) and written down in an educational text which was provided to students (the project curriculum). The practicality of the educational test was verified by an educational test the results of which were statistically processed (implemented curriculum). The statistical analysis of the test results confirmed the second hypothesis of this work. "The knowledge of future experts in the field of the protection of population will have, from the point of view of the role of the complementarity principle in their preparation, a theoretical division which will be close to the normal division." By confirming this hypothesis, the correctness and applicability of the curriculum process were confirmed as it was assumed by the first hypothesis: "Using the stages of a curriculum process, an educational basis of the role of the complementarity principle can be created within a quantitative research." The contributions of this work can be summarized by following points: 1) The use of an educational text in the preparation of experts in the field of the protection of population (a practical contribution of this diploma thesis). 2) The improvement of the applicability of the theory of the curriculum process in the field of the protection of population which has not been researched so far (the improvement of the theory of the curriculum process). 3) The definition of the link of the physical aspect of the complementarity principle to the general form of this principle (the theoretical contribution of this diploma thesis).