<p> The relative cumulative yields of krypton and xenon isotopes from the thermal neutron fission of 237Np and Np238 and from the fast neutron fission of Np237 have been measured by means of a mass spectrometer. These are the first fission yield results for 238Np, and the first for 237Np at thermal neutron energies. The results are compared with those from other fissioning nuclides.</p> <p> Independent yields of the shielded nuclides 80Br, 82Br, 128I, and 130I from the thermal neutron fission of 235U, 233U, 239Pu, and 238Np have been determined by mass spectrometric analyses of the krypton and xenon β-decay products. The results are discussed in terms of conventional charge distribution theories, and also in terms of neutron emission effects.</p> / Thesis / Doctor of Philosophy (PhD)

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付記する学位プログラム名: 霊長類学・ワイルドライフサイエンス・リーディング大学院 / 京都大学 / 新制・課程博士 / 博士(理学) / 甲第24466号 / 理博第4965号 / 新制||理||1709(附属図書館) / 京都大学大学院理学研究科生物科学専攻 / (主査)教授 古市 剛史, 准教授 Huffman Michael Alan, 教授 今井 啓雄 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM

The absolute abundances of fission-product xenon and krypton isotopes in six uranium minerals were determined mass spectrometrically using the isotope dilution technique. The fission products were resolved into a U spontaneous fission component, a U 235 neutron-induced fission component, and a U 238 neutron-induced fission component. The presence of U 238 of neutron-induced fission indicated that t he neutron energies in uranium minerals were higher than had been suspected. Internal consistency in the analysis was achieved only when the I 29 yield in u235 thermal neutron fission reported by Purkayastha and Martin was lowered by 20%. The number of U 238 spontaneous fissions was calculated from the lead age, U 238 content, and the U 238 pontaneous fission half life. A comparison of the number of fission products from U 238 spontaneous fission and the number of spontaneous fissions in each of the six minerals showed that five of the six minerals had lost large portions of their noble gases. A fractionation of krypton relative to xenon accompanied this loss. The results obtained for the sixth mineral indicated little or no loss of xenon and krypton. Absolute yields for U 238 spontaneous fission were therefore determined from an analysis of this mineral. / Thesis / Doctor of Philosophy (PhD)

Isotopic abundances of the elements barium, cerium, neodymium, samarium and europium formed in the thermal neutron fission of have been studied with a mass spectrometer. Suitable analyses of very young and old fission products have made possible the normaliza­tion of the isotopic abundances of each of these elements through iso­baric nuclides. In this manner the relative cumulative fission yield of every fission chain from mass 137 to 154 has been obtained. These yields, together with previously reported relative yields of masses 131 to 137 when normalized to total 100%, give the absolute cumulative yield of all the significant heavy fragment chains. The origin of the fine structure found in this mass yield distribution is discussed. It has been found that all fine structure can be explained in terms of a smooth primary mass-yield curve and a simple neutron distribution both of which are compared with experimental data from other laboratories. / Thesis / Doctor of Philosophy (PhD)

The purpose of this thesis is to examine the accuracy of the RAPID (Real-Time Analysis for Particle Transport and In-situ Detection) eigenvalue algorithm based on a few problems from the ICSBEP (International Criticality Safety Benchmark Evaluation Project) Handbook. RAPID is developed based on the MRT (Multi-Stage Response-Function Transport) methodology and it uses the fission matrix (FM) method for performing eigenvalue calculations. RAPID has already been benchmarked based on several real-world problems including spent fuel pools and casks, and reactor cores. This thesis examines the accuracy of the RAPID eigenvalue algorithm for modeling the physics of problems with unique geometric configurations. Four problems were selected from the ICSBEP Handbook; these problems differ by their unique configurations which can effectively examine the capability of the RAPID code system. For each problem, a reference Serpent Monte Carlo calculation has been performed. Using the same Serpent model in the pRAPID (pre- and post-processing for RAPID) utility code, a series of fixed-source Serpent calculations are performed to determine spatially-dependent FM coefficients. RAPID calculations are performed using these FM coefficients to obtain the axially-dependent, pin-wise fission density distribution and system eigenvalue for each problem. It is demonstrated that the eigenvalues calculated by RAPID and Serpent agree with the experimental data within the given experimental uncertainty. Further, the detailed 3-D pin-wise fission density distribution obtained by RAPID agrees with the reference prediction by Serpent which itself has converged to less than 1% weighted uncertainty. While achieving accurate results, RAPID calculations are significantly faster than the reference Serpent calculations, with a calculation time speed-up of between 4x and 34x demonstrated in this thesis. In addition to examining the accuracy of the RAPID algorithm, this thesis provides useful information on the use of the FM method for simulation of nuclear systems. / Master of Science / In the modeling and simulation of nuclear systems, two parameters are of key importance: the system eigenvalue and the fission distribution. The system eigenvalue, known as kef f , is the ratio of neutron production from fission in the current neutron generation compared with the absorption and leakage of neutrons from the system in the previous neutron generation. When this ratio is equal to one, the system is critical and is a self-sustaining chain reaction. Knowledge of the fission distribution is important in the nuclear power industry, as it enables engineers to determine the best reactor core assembly configuration to maintain an even power distribution. Several methods have been developed over the years to effectively solve for a nuclear systems fission distribution and system eigenvalue. Aspects of both Monte Carlo and deterministic transport methods have been combined into RAPID’s MRT methodology. It is capable of accurately determining the system eigenvalue and fission distribution in real time. This thesis examines the accuracy of the RAPID algorithm using four unique problems from the ICSBEP handbook. These problems help us to test the limits of the FM method in RAPID through the modeling of small, unique geometric configurations not seen in large, uniformly configured power reactor cores and spent fuel pools. For comparison, each problem is modeled using the Serpent Monte Carlo code, an accurate code meant to serve as the industry standard for determination of the fission distribution of each problem. This model is then used to generate a set of FM coefficients for use in RAPID calculations. It is demonstrated that the eigenvalues calculated by RAPID and Serpent agree with the experimental data within the given experimental uncertainty. The fission distribution obtained by RAPID is also in agreement with the Serpent reference model. Finally, the RAPID eigenvalue calculation is significantly faster than the corresponding Serpent reference model, with speed-ups ranging from 4x to 34x demonstrated.

Les mitochondries sont des organelles de quelques micromètres qui proviendraient de l'incorporation d'une alpha-protéobactérie dans le cytoplasme des cellules eucaryotes par endosymbiose. Dans les cellules eucaryotes, la mitochondrie joue un rôle central dans la production d'ATP, mais aussi dans la mort cellulaire programmée par apoptose ainsi que dans la biosynthèse de nombreuses molécules. Les mitochondries sont très polymorphes, leurs taille, forme et organisation varient considérablement selon le type cellulaire ou l'état physiologique ou pathologique de la cellule. Depuis une vingtaine d'année, l'étude des mécanismes qui contrôlent la morphogenèse, la dynamique de fission et de fusion mitochondriale et leurs rôles physiologiques est devenue un domaine majeur dans la recherche sur la mitochondrie. De plus, avec les progrès de la vidéo-microscopie, il est devenu possible de filmer des mitochondries dans le cytoplasme de cellules vivantes. Durant ma thèse, j'ai participé à la caractérisation de la fonction du gène Pantagruelian Mitochondria I (PMI), un nouveau déterminant de la morphologie des mitochondries que nous avons découvert chez la drosophile. PMI est une protéine de la membrane interne qui, en intervenant dans l'organisation de cette membrane, est indispensable à la formation de mitochondries de forme tubulaire. J'ai également contribué au développement d'outils et de méthodologies permettant la visualisation et l'étude de la dynamique mitochondriale dans des embryons de drosophiles vivants. / Mitochondria are organelles which are a few micrometers long and are originated from the incorporation of an alpha-proteobacteria in the cytoplasm of eukaryotic cells through endosymbiosis. In eukaryotic cells, mitochondria play a central role in ATP production as well as in programmed cell death and in the biosynthesis of many molecules. Mitochondria are highly polymorphic in size and form. Their organization also varies considerably according to the cell type or physiological or pathological state of the cell. In the last two decades, the study of the mechanisms controlling morphogenesis, dynamic of mitochondrial fission and fusion and their physiological roles has become a major research field of mitochondria. In addition, the progress in video-microscopy enable to record mitochondrial dynamics in the cytoplasm of living cells. I participated in the research on the characterization of gene function called Pantagruelian Mitochondria I (PMI), a novel determinant of the mitochondrial morphology that we discovered in Drosophila. PMI, a protein of the inner membrane, is involved in its membrane organization and essential to form tubular mitochondria. I also contributed to the development of experimental tools and protocols to visualize and study the mitochondrial dynamics in living Drosophila embryos. Interestingly, a stereotyped process of mitochondrial remodeling during Drosophila embryogenesis has been found and it raised a question about its role in developmental processes through my work.

Le sujet de cette thèse de doctorat consiste à proposer une architecture ambiante d’interaction homme-robot-environnement. Dans le cadre de la robotique d’aide à la personne dépendante. Cette architecture va permettre aux robots « Ubiquitous Networked Robots » de prendre en compte le contexte évolutif pour fournir continuellement du service à l'utilisateur. L'architecture proposée utilise le concept d'Ontologie du domaine pour la description de l'environnement. Nous avons choisi d'utiliser l'outil open source PROTEGE qui va nous permettre de définir l'ontologie ainsi que les moteurs de fusion et de fission. Les entrées multimodales seront fusionnées puis subdivisées en tâches élémentaires et envoyées comme commandes au fauteuil roulant muni d'un bras manipulateur. Cette architecture sera validée par des spécifications et des simulations via des réseaux de Pétri temporels et stochastiques. / The subject of this thesis is to provide an ambient architecture for the human-robotenvironment interaction, as part of thedependent person robotics help. This architecture will enable the robot to take into account the changing context and continually provide a service to the user. The architecture uses the concept of ontology for the descriptionof the environment. We have chosen to use the open source PROTEGE because it allows the definition of the ontology and the fusion and fission engines. Indeed, multimodal inputs will be merged and subdivided into elementary tasks and sent tocontrol the wheelchair with the manipulated arm. This architecture will be validated by specifications and simulations via temporal and stochastic Petri nets.

La fission nucléaire, bien que connue depuis 80 ans, reste un défi théorique. La complexité et la multiplicité des interactions au sein d’un noyau fissionnant rend la modélisation du phénomène de fission délicate. Les modèles de fission nucléaire peinent à reproduire les observables. Parmi ces observables, les rendements de fissions sont pourtant des ingrédients clés pour la physique des réacteurs. S’ils ne peuvent être prédis efficacement, il est nécessaire de les mesurer.Les bibliothèques de données nucléaires évaluées, qui condensent la connaissance actuelle de ces rendements de fission, présentent pourtant des incertitudes importantes, ainsi que des divergences.Depuis quelques années, une collaboration entre le CEA, le CNRS et l’Institut Laue Langevin (ILL) vise à mesurer avec précision les rendements de la fission induite par neutron thermique pour des actinides d’importance pour les cycles Uranium-Plutonium et Thorium-Uranium, afin de compléter les connaissances actuelles et également fournir des données de référence pour le test de modèles.En particulier, au cours de cette thèse, des données expérimentales, acquises sur le spectromètre de masse LOHENGRIN à l’ILL de Grenoble (France), ont été analysées pour le 239Pu(nth,f) et le 241Pu(nth,f). Deux types de rendements ont été déterminées : des rendements en masse, à l’aide d’une chambre d’ionisation, et des rendements isotopiques, par spectrométrie γ avec des détecteurs Ge.Grâce à un protocole expérimental rigoureux testant la reproductibilité des observables et une méthode d’analyse innovante, adaptée en particulier à l’estimation des covariances et à leurs propagations, les rendements en masse obtenus présentent des incertitudes réduites et une matrice de covariance expérimentale complète. Celle-ci est essentielle pour la compréhension et l’utilisation des données mesurées.Les rendements isotopiques obtenus sont fortement dépendants des données de structure nucléaire, et présentent de facto des incertitudes importantes. L’amélioration future des données de structure permettra, grâce aux outils d’analyse développés, de réduire l’incertitude des rendements isotopiques mesurés.D’autres observables d’intérêts ont pu être extraites des mesures, en particulier la distribution de l’énergie cinétique moyenne des produits de fission en fonction de leur masse, ainsi que la polarisation de charge pour une partie du pic lourd. Ces données sont complémentaires aux rendements et présentent un intérêt pour les modèles et les futures évaluations. / Nuclear fission, although known for 80 years, remains a theoretical challenge. The complexity and multiplicity of interactions within a splitting nucleus make the modelling of the fission phenomenon delicate. Nuclear fission models struggle to replicate observables. Among these observables, however, fission yields are key ingredients for reactor physics. If they cannot be predicted effectively, it is necessary to measure them.The evaluated nuclear data libraries, which condense the current knowledge of these fission yields, nevertheless present significant uncertainties, as well as discrepancies.For several years, a collaboration between the CEA, the CNRS and the Laue Langevin Institute (ILL) has aimed at accurately measuring the yields of thermal neutron induced fission for actinides of importance for the Uranium-Plutonium and Thorium-Uranium cycles, in order to complete current knowledge and also provide reference data for model testing.In particular, during this thesis, experimental data acquired on the LOHENGRIN mass spectrometer at the ILL in Grenoble (France) were analysed for 239Pu(nth,f) and 241Pu(nth,f). Two types of yields were determined: mass yields, using an ionization chamber, and isotopic yields, by spectrometry γ with Ge.Thanks to a rigorous experimental protocol testing the reproducibility of the observables and an innovative analytical method, adapted in particular to the estimation of covariances and their propagation, the mass yields obtained present reduced uncertainties and a complete experimental covariance matrix. This is essential for understanding and using the measured data.The isotopic yields obtained are highly dependent on the nuclear structure data, and de facto present significant uncertainties. The future improvement of the nuclear structure data will allow, thanks to the analysis tools developed, to reduce the uncertainty of the isotopic yields measured.Other observables of interest have been extracted from the measurements, in particular the average kinetic energy distribution of the fission products as a function of their mass, as well as the charge polarization for part of the heavy peak. These data are complementary to fission yields and are of interest for models and future evaluations.