This thesis critically evaluates the policies, processes and practices of medical waste management in selected rural hospitals in the Eastern Cape. Medical Waste Management is a growing public health and environmental issue worldwide. Research shows large scale incapacity in dealing with medical waste in an efficient and sustainable fashion globally, which demonstrates that it is not merely a developing world problem alone. This study is conducted against the backdrop of an increasing medical waste crisis in South Africa. Although there are an abundance of studies on solid waste management, there is a lack of data and research particularly on medical waste management in rural hospitals. The crisis of medical waste management in South Africa is closely intertwined with the collapsing health care system and an overburdened natural environment. It is an undisputable fact that South Africa’s generation of medical waste far exceeds its capacity to handle it effectively. This thesis argues that the neglect of medical waste as an environmental-health issue and the absence of an integrated national medical waste management plan aggravate the medical waste problem in the country. In explaining the medical waste crisis, this thesis adopts a Marxist perspective which is based on the premise that industrial capitalist societies place economic growth and production at high priority at the expense of the natural environment; creating a society that is engulfed by high health risk due to the generation of hazardous and toxic waste. Industrial societies view themselves as superior and separate from the natural environment, whereas one cannot separate nature from society as they are interlinked. As society attempts to adopt a sustainable environmental approach towards environmental management, science and technology are enforced as a solution to environmental problems in order to continue developing countries’ economies whilst sustainably managing and protecting the environment, which is contradictory. This thesis emphasises that medical waste management is a socio-political problem as much as it is an environmental problem, hence the need to focus on power relations and issues of environmental and social justice. The results of the study identified gaps in policy framework nationally and institutionally on medical waste management. In addition, there were poor waste management practices due to poor training, inadequate infrastructure and resources as well as poor budget support.

Master of Science

Adsorption of radionuclides in granite pores and micropores ABSTRACT This graduation thesis deals with laboratory determination of adsorption isotherms parameters. Granite from the central moldanubian pluton, site Panské Dubenky, Czech Republic, was chosen to the experiment. The place is one of the candidate sites to build a deep nuclear waste disposal. A batch experiment was performed in two modes, differing in the way of addition of radioactive nuclide 90 Sr. From this experiment, distribution coefficients for a linear isotherm or parameters for Langmuir isotherm were obtained. Beside this, a through-diffusion experiment was performed. The objective of this experiment was to identify whether some of the radionuclides used (137 Cs, 90 Sr, 125 I) is able to penetrate through the pores of a granite slice barrier between two solutions of different concentrations. During the period of the experiment no radionuclide was detected reliably.

Im Mai 2017 wurde das „Gesetz zur Suche und Auswahl eines Standortes für ein Endlager für hochradioaktive Abfälle“ (Standortauswahlgesetz -StandAG) vom Bundestag und Bundesrat neu verabschiedet. In diesem Gesetz sind sämtliche Kriterien (geowissenschaftliche Kriterien, planungswissenschaftliche Kriterien, Kriterien für Sicherheitsuntersuchungen) erstmals gesetzlich festgelegt, die für die zukünftige Auswahl eines Standortes für ein Endlager für hoch radioaktive Wärme entwickelnde Abfälle (ausgediente Brennelemente und Abfälle aus der Wiederaufarbeitung bestrahlter Brennelemente) in Deutschland gelten. Die Kriterien sind vorab durch die „Kommission Lagerung hochradioaktiver Abfallstoffe“ (Endlagerkommission) in zweijähriger Arbeit von 2014 bis 2016 in kontroverser Diskussion festgelegt worden. In diesem Beitrag werden die geowissenschaftlichen Kriterien und die Phasen im Standortauswahlverfahrens kurz vorgestellt. Der Autor war Mitglied der Endlagerkommission. / In May 2017, the 'Act on the Search for and Selection of a Site for a Repository for Highly Radioactive Waste' (Site Selection Act - StandAG) was passed by the German “Bundestag” and “Bundesrat”. This Act for the first time defines by law all the criteria (geoscientific criteria, planning criteria, criteria for safety investigations) that apply to the future selection of a site for a repository for high-level radioactive, heat-generating waste (spent fuel elements and waste from the reprocessing of spent fuel elements) in Germany. The criteria have been defined in advance by the 'Commission on the Storage of Highly Radioactive Waste Materials' (Final Storage Commission; “Endlagerkommission”) in a controversial discussion during two years of work from 2014 to 2016. In this article, the geoscientific criteria and the phases in the site selection process are briefly presented. The author was member of the Repository Commission.

京都大学 / 新制・課程博士 / 博士(エネルギー科学) / 甲第23290号 / エネ博第415号 / 新制||エネ||80(附属図書館) / 京都大学大学院エネルギー科学研究科エネルギー社会・環境科学専攻 / (主査)教授 石原 慶一, 教授 手塚 哲央, 教授 大垣 英明 / 学位規則第4条第1項該当 / Doctor of Energy Science / Kyoto University / DFAM

Thesis: M.S., Massachusetts Institute of Technology, Department of Nuclear Engineering, 1977 / Includes bibliographical references. / M.S. / M.S. Massachusetts Institute of Technology, Department of Nuclear Engineering

This study includes a systematic investigation of the bond strength of cementitious borehole plugs in welded tuff. Analytical and numerical analysis of borehole plug-rock stress transfer mechanics is performed. The interface strength and deformation are studied as a function of Young's modulus ratio of plug and rock, plug length and rock cylinder outside-to-inside radius ratio. The tensile stresses in and near an axially loaded plug are analyzed. The frictional interface strength of an axially loaded borehole plug, the effect of axial stress and lateral external stress, and thermal effects are also analyzed. Implications for plug design are discussed. Push-out tests are used to determine the bond strength by applying an axial load to the cement plugs. A total of 130 push-out tests are performed as a function of borehole size, plug length, temperature, and degree of saturation of the tuff cylinder. The use of four different borehole radii enables evaluation of size effects. A well-defined exponential strength decrease with increasing plug diameter results.

Todo e qualquer tipo de rejeito deve ser tratado e armazenado adequadamente. Portanto os rejeitos radioativos requerem gerenciamento apropriado e seguro, desde sua geração até seu armazenamento em repositório. O principal propósito da gerência de rejeitos radioativos é preservar a vida humana e o meio ambiente. O objetivo da pesquisa foi caracterizar algumas argilas brasileiras de modo a avaliar a viabilidade de seu uso na camada de recheio, uma das barreiras de um repositório de rejeitos radioativos. A principal função desta barreira é contribuir para retardar o movimento de radionuclídeos e previnir sua liberação para o ambiente. Quatro argilas de fornecedores nacionais foram selecionadas para a pesquisa: montmorilonita cálcica (Dol 01), montmorilonita sódica (Dol 02), caulinita (Ind 01) e vermiculita (Ubm 04). Foram determinadas suas caracteristicas físicas, químicas e mineralógicas e também seu potencial de sorção dos cátions césio e o estrôncio. Foi confirmada por meio destes resultados relação direta entre a superfície específica (SE), a capacidade de troca catiônica (CTC) e o pH destas argilas, na seguinte ordem crescente: Ind 01, Dol 01 e Dol 02. De acordo com os modelos de Freundlicdh (Kf) e Langmuir (M), as argilas Dol 01 e Dol 02 foram melhores sorvedoras de Sr2+. A variação de energia livre de Gibbs também foi calculada para as reações de sorção entre as argilas e os cátions e para todas as argilas, esta variação for negativa, confirmando a espontaneidade das reações de sorção. / Wastes in general should be properly treated and stored. Then the radioactive wastes also rquire suitable and safe management beginning in their generation until the storage in repository. The main purpose of the radioactive waste management is to preserve the human beings and the environment. The objective of this research ws to characterize some brasilian clays in order to evaluate of their use in the backfill layer, one of the radioactive waste repository barriers. The main function of this barrier to contribute in the delay of the radionuclides movement, and to prevent their release into the environment. Four clays provided by national suppliers were selected for the research: Ca-Montmorillonite (Dol 01), Na-Montmorillonite (Dol 02), Kaolinite (Ind 01) and Vermiculite (Ubm 04). Their physical, chemical and mineralogical characteristics were determined, and also their sorption potential of Cesium and Strontium cations. It was confirmed through these results a direct relationship among their specific surface (SS), the capacity of cationic exchange (CCE) and pH. The CCE results followed this increasing order: Ind 01, Dol 01, and Dol 02. In accordance with the models of Freundlich (Kf) and Langmuir (M), the clays Dol 01 and Dol 02 were the best sobers of Sr2+. The Ind 01 and Ubm 04 were the best ones in the case of Cs+. The Gibbs free energy change was calculated for the sorption reactions between the clays and the cations, and it was negative for all clays, confirming the sorption spontaneity.

Dans le but de vérifier l'efficacité des dispositifs de scellement ou des barrières ouvragées dans le stockage géologique des déchets radioactifs, l'Institut de Radioprotection et de Sûreté Nucléaire (IRSN) a mis en œuvre le projet expérimental SEALEX (SEALing performance EXperiments) auquel ce travail est étroitement lié. Dans le cadre de ce projet, des essais in-situ sont effectués à l'échelle représentative et dans des conditions naturelles sur un mélange compacté de bentonite et de sable. Ce matériau de mélange a été choisi pour sa faible perméabilité et surtout pour sa capacité de gonflement qui permet de colmater les vides existant dans le système, notamment le vide technologique correspondant au vide radial entre le noyau de scellement et la roche hôte et qui est inévitable au cours de l'installation du noyau dans le forage. Une fois les vides scellés, le gonflement à volume constant engendre une pression de gonflement aussi bien sur la roche hôte (radiale) que sur les structures de confinement en béton (axiale). Le comportement de ce matériau dans ces conditions de couplages hydromécaniques est alors étudié dans ce travail. La microstructure du matériau à son état initial a été premièrement examinée par micro-tomographie rayons-X. Ceci a permis de voir la distribution des grains de bentonite et de sable ainsi que le réseau de pores dans l'échantillon. Des macro-pores se sont retrouvés concentrés à la périphérie de l'échantillon ainsi qu'entre les grains de sable, ce qui pourra affecter à court terme la perméabilité. L'hydratation du même matériau en condition de gonflement limité a été ensuite observée par une photographie 2D et par la micro-tomographie aux rayons-X. Le mécanisme de gonflement par production de gel de bentonite, la cinétique de gonflement, la diminution de densité et l'homogénéisation du matériau final on été analysés. L'hydratation en conditions de gonflement empêché a été aussi étudiée par des essais où la pression de gonflement a été mesurée dans deux directions : radialement et axialement. La différence retrouvée entre les pressions de gonflement axiales et radiales a évoqué la présence d'une anisotropie de microstructure qui a été analysée en fonction de la masse volumique sèche de bentonite dans le mélange. Des essais en modèle réduit reproduisant à une échelle 1/10ème les essais in situ (SEALEX) ont été également effectués afin d'étudier le comportement du noyau compacté après la reprise des vides au cas d'un accident détruisant les éléments de confinement. Des mesures locales de pression de gonflement le long des échantillons ont permis de mettre en évidence l'évolution du gradient de densité durant le gonflement axial. Finalement une comparaison entre les résultats obtenus dans ce travail et ceux d'un essai in situ (SEALEX) a été faite. Une bonne correspondance entre les valeurs d'humidités relatives a été retrouvée pour les mêmes longueurs d'hydratation tout en prenant en compte la saturation par le vide technologique radial. Par contre, la comparaison des évolutions et des valeurs de pressions de gonflement était plus compliquée vu les différences de configurations des essais / In order to verify the effectiveness of the geological high-level radioactive waste disposal, the French Institution of Radiation protection and Nuclear Safety (IRSN) has implemented the SEALEX project to control the long-term performance of swelling clay-based sealing systems, and to which this work is closely related. Within this project, In-situ tests are carried out on compacted bentonite-sand mixture in natural conditions and in a representative scale. This material is one of the most appropriate sealing materials because of its low permeability and good swelling capacity. Once installed, this material will be hydrated by water from the host-rock and start swelling to close all gaps in the system, in particular the internal pores, rock fractures and technological voids. Afterwards, swelling pressure will develop. In the present work, laboratory experiments were performed to investigate the sealing properties under this complex hydro-mechanical conditions taking into consideration the effect of technological voids. The microstructure of the material in its initial state was first examined by microfocus X-ray computed tomography (µCT). This allowed identification of the distribution of grains of sand and bentonite as well as the pores in the sample. Macro-pores are found concentrated at the periphery of the sample and between the grains of sand, which could affect in the short term the permeability. The hydration of the same material in limited swelling conditions was then observed by 2D photography and 3D µCT. The swelling mechanism with bentonite gel production, the swelling kinetics, the density decrease and the homogenisation of the material were analyzed. The hydration in the conditions of prevented swelling was also studied by swelling pressure tests with radial and axial measurements of swelling pressure. The difference found between the axial and radial swelling pressures suggested the presence of an anisotropic microstructure. Mock-up tests at a 1/10 scale of the in situ SEALEX tests were carried out for the study of the recovery capacity of the mixture in case of an accident causing the failure of the confining structures. Local measurements of swelling pressures along the sample allowed analysis of the density gradient evolution during axial swelling. Finally, a comparison between the laboratory results and those from an in-situ test was done, showing a good fitting in the relative humidity curves for the same infiltration length while considering the saturation effect from the technological void. The swelling pressure comparison was more complex because of the different configurations of the tests (existence of technological void in-situ that could affect the kinetics)

Recent nuclear proliferation concerns and disarmament agreements have encouraged the U.S. to decrease the excess amount of weapons-grade and reactor-grade plutonium. Continued use of nuclear power without a permanent solution for waste disposition has also led to the need for a reliable method by which the waste products, specifically plutonium, can be utilized or destroyed. One possible solution to plutonium destruction is achieved by manufacturing it into small microspheres and embedding it within an inert metal matrix, then placing it inside a conventional nuclear reactor. This process would burn some of the plutonium while producing electricity. PuO2Zr dispersion fuel has been proposed for such a purpose. Prior to its use, however, this non-fertile metal matrix dispersion fuel must be shown to be mechanically stable in the reactor environment. The internal mechanical interactions of dispersion fuel were modeled using finite element analysis. The results were used to assess the stability of PuO2Zr dispersion fuel inside a reactor. Several parameters, including fuel particle size, volumetric loading, temperature, and burnup, were varied to determine the maximum amount of plutonium that can be burned while maintaining fuel integrity. Earlier experiments using UO2 stainless steel dispersion fuels were used to validate the model and establish a failure criterion. The validated model was then used to determine the parameter space over which PuO2Zr dispersion fuel can be successfully used. These results show that PuO2Zr dispersion fuel is robust and may offer a reliable method for plutonium disposal in current reactors.