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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Annual Report 2015 Institute of Resource Ecology

28 July 2016 (has links) (PDF)
The Institute of REsource Ecology (IRE) is one of the eight institutes of the Helmholtz-Zentrum Dresden-Rossendorf (HZDR). The research activities are mainly integrated into the program “Nuclear Waste Management, Safety and Radiation Research (NUSAFE)” of the Helmholtz Association (HGF) and focused on the topics “Safety of Nuclear Waste Disposal” and “Safety Research for Nuclear Reactors”. Additionally, various activities have been started investigating chemical and environmental aspects of processing and recycling of strategic metals, namely rare earth elements. These activities are located in the HGF program “Energy Efficiency, Materials and Resources (EMR)”. Thus, all scientific work of the IRE belongs to the research field “Energy” of the HGF. The research objective is the protection of humans and the environment from hazards caused by pollutants resulting from technical processes that produce energy and raw materials. Treating technology and ecology as a unity is the major scientific challenge in assuring the safety of technical processes and gaining their public acceptance. We investigate the ecological risks ensued by radioactive and non-radioactive metals in the context of nuclear waste disposal, the production of energy in nuclear power plants and in processes along the value chain of metalliferous raw materials. A common goal is to generate better understanding about the dominating processes essential for metal mobilization and immobilization on the molecular level by using advanced spectroscopic methods. This in turn enables us to assess the macroscopic phenomena, including models, codes and data for predictive calculations, which determine the transport and distribution of contaminants in the environment.
2

Annual Report 2015 Institute of Resource Ecology

Stumpf, Thorsten, Foerstendorf, Harald, Bok, Frank, Richter, Anke 28 July 2016 (has links)
The Institute of REsource Ecology (IRE) is one of the eight institutes of the Helmholtz-Zentrum Dresden-Rossendorf (HZDR). The research activities are mainly integrated into the program “Nuclear Waste Management, Safety and Radiation Research (NUSAFE)” of the Helmholtz Association (HGF) and focused on the topics “Safety of Nuclear Waste Disposal” and “Safety Research for Nuclear Reactors”. Additionally, various activities have been started investigating chemical and environmental aspects of processing and recycling of strategic metals, namely rare earth elements. These activities are located in the HGF program “Energy Efficiency, Materials and Resources (EMR)”. Thus, all scientific work of the IRE belongs to the research field “Energy” of the HGF. The research objective is the protection of humans and the environment from hazards caused by pollutants resulting from technical processes that produce energy and raw materials. Treating technology and ecology as a unity is the major scientific challenge in assuring the safety of technical processes and gaining their public acceptance. We investigate the ecological risks ensued by radioactive and non-radioactive metals in the context of nuclear waste disposal, the production of energy in nuclear power plants and in processes along the value chain of metalliferous raw materials. A common goal is to generate better understanding about the dominating processes essential for metal mobilization and immobilization on the molecular level by using advanced spectroscopic methods. This in turn enables us to assess the macroscopic phenomena, including models, codes and data for predictive calculations, which determine the transport and distribution of contaminants in the environment.
3

Annual Report 2010 - Institute of Radiochemistry

23 August 2011 (has links) (PDF)
At the beginning of 2011, the former Forschungszentrum Dresden-Rossendorf (FZD) was fully integrated into the Helmholtz Association, as Helmholtz-Zentrum Dresden-Rossendorf (HZDR). Therefore, the present Annual Report 2010 of the Institute of Radiochemistry (IRC) is published as the first HZDR-Report. The Institute of Radiochemistry is one of the six Research Institutes of this centre. IRC contributes to the research program “Nuclear Safety Research” in the “Research Field of Energy” and performs basic and applied research in radiochemistry and radioecology. Motivation and background of our research are environmental processes relevant for the installation of nuclear waste repositories, for remediation of uranium mining and milling sites, and for radioactive contaminations caused by nuclear accidents and fallout. Because of their high radiotoxicity and long half-life the actinides are of special interest.
4

Annual Report 2012 - Institute of Resource Ecology

08 May 2013 (has links) (PDF)
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”.
5

Annual Report 2011 - Institute of Radiochemistry

14 March 2012 (has links) (PDF)
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.
6

Annual Report 2010 - Institute of Radiochemistry

Bernhard, Gert, Foerstendorf, Harald, Richter, Anke, Viehweger, Katrin January 2011 (has links)
At the beginning of 2011, the former Forschungszentrum Dresden-Rossendorf (FZD) was fully integrated into the Helmholtz Association, as Helmholtz-Zentrum Dresden-Rossendorf (HZDR). Therefore, the present Annual Report 2010 of the Institute of Radiochemistry (IRC) is published as the first HZDR-Report. The Institute of Radiochemistry is one of the six Research Institutes of this centre. IRC contributes to the research program “Nuclear Safety Research” in the “Research Field of Energy” and performs basic and applied research in radiochemistry and radioecology. Motivation and background of our research are environmental processes relevant for the installation of nuclear waste repositories, for remediation of uranium mining and milling sites, and for radioactive contaminations caused by nuclear accidents and fallout. Because of their high radiotoxicity and long half-life the actinides are of special interest.
7

Russlands Politik zur nuklearen Abschreckung im Diskurs 2020

31 August 2020 (has links)
Thema: Russlands Politik zur nuklearen Abschreckung im Diskurs 2020 • Zwei Meinungsbeiträge (Übers. dt.) zur Abschreckungsdoktrin; • Kommentar (dt.) zu den Meinungsbeiträgen; • Im Anhang: Text (Übers. dt.) Grundlagendokument der Russischen Föderation zur nuklearen Abschreckung (2020).:Inhalt: • Vorwort (dt.) des Herausgebers, Anmerkungen zur Übersetzung. • Übersetzung (dt.) aus dem Russischen von Rainer Böhme: - Andrej Sterlin / Alexander Chrjapin: 'Zu den Grundlagen der staatlichen Politik der RF auf dem Gebiet der nuklearen Abschreckung'. (Aus: Krasnaja Swesda, Moskau, 7. August 2020). - Alexander Timochin: 'Russland ändert sein Herangehen an die nukleare Abschreckung'. (Aus: Militärrundschau, Moskau, 13. Juni 2020). - ANHANG: Offizielles Dokument vom 2. Juni 2020: 'Grundlagen der staatlichen Politik der Russischen Föderation auf dem Gebiet der nuklearen Abschreckung (2020)'.
8

Russlands Politik zur nuklearen Abschreckung am Beginn der 2020er Jahre

22 June 2020 (has links)
Thema: Russlands Politik zur nuklearen Abschreckung am Beginn der 2020er Jahre. • Kommentar (dt.), Stellungnahme (Übers. a.d. Eng.) und • Originaltextdokumente zu Russlands Nuklearabschreckung: - Präsidenten-Erlass 2020 (dt./russ.) und - Grundlagendokument 2020 (dt.):Inhalt: 1 • Vorwort des Herausgebers, Anmerkungen zur Übersetzung. 2 • Wilfried Schreiber: Kommentar - Hat Russland eine neue Nukleardoktrin? Übersetzung a. d. Engl. von Rainer Böhme: 3 • Dmitri Trenin: Stellungnahme zum Grundlagenpapier 2020. Übersetzung a. d. Russ. von Rainer Böhme: 4 • Erlass des Präsidenten der Russischen Föderation (dt./ru.) Übersetzung a. d. Russ. von Rainer Böhme: 5 • Dokument - GRUNDLAGEN der staatlichen Politik der Russischen Föderation auf dem Gebiet der nuklearen Abschreckung (2020)
9

Validation and Application of the System Code TRACE for Safety Related Investigations of Innovative Nuclear Energy Systems

Jäger, Wadim 04 September 2012 (has links) (PDF)
The system code TRACE is the latest development of the U.S. Nuclear Regulatory Commission (US NRC). TRACE, developed for the analysis of operational conditions, transients and accidents of light water reactors (LWR), is a best-estimate code with two fluid, six equation models for mass, energy, and momentum conservation, and related closure models. Since TRACE is mainly applied to LWR specific issues, the validation process related to innovative nuclear systems (liquid metal cooled systems, systems operated with supercritical water, etc.) is very limited, almost not existing. In this work, essential contribution to the validation of TRACE related to lead and lead alloy cooled systems as well as systems operated with supercritical water is provided in a consistent and corporate way. In a first step, model discrepancies of the TRACE source code were removed. This inconsistencies caused the wrong prediction of the thermo physical properties of supercritical water and lead bismuth eutectic, and hence the incorrect prediction of heat transfer relevant characteristic numbers like Reynolds or Prandtl number. In addition to the correction of the models to predict these quantities, models describing the thermo physical properties of lead and Diphyl THT (synthetic heat transfer medium) were implemented. Several experiments and numerical benchmarks were used to validate the modified TRACE version. These experiments, mainly focused on wall-to-fluid heat transfer, revealed that not only the thermo physical properties are afflicted with inconsistencies but also the heat transfer models. The models for the heat transfer to liquid metals were enhanced in a way that the code can now distinguish between pipe and bundle flow by using the right correlation. The heat transfer to supercritical water was not existing in TRACE up to now. Completely new routines were implemented to overcome that issue. The comparison of the calculations to the experiments showed, on one hand, the necessity of these changes and, on the other hand, the success of the new implemented routines and functions. The predictions using the modified TRACE version were close to the experimental data. After validating the modified TRACE version, two design studies related to the Generation IV International Forum (GIF) were investigated. In the first one, a core of a lead-cooled fast reactor (LFR) was analyzed. To include the interaction between the thermal hydraulic and the neutron kinetic due to temperature and density changes, the TRACE code was coupled to the program system ERANOS2.1. The results gained with that coupled system are in accordance with theory and helped to identify sub-assemblies with the highest loads concerning fuel and cladding temperature. The second design which was investigated was the High Performance Light Water Reactor (HPLWR). Since the design of the HPLWR is not finalized, optimization of vital parameters (power, mass flow rate, etc.) are still ongoing. Since most of the parameters are affecting each other, an uncertainty and sensitivity analysis was performed. The uncertainty analysis showed the upper and lower boundaries of selected parameters, which are of importance from the safety point of view (e.g., fuel and cladding temperature, moderator temperature). The sensitivity study identified the most relevant parameters and their influence on the whole system.
10

Untersuchungen zur Hochrateabscheidung harter DLC-Schichten

Graupner, Karola 11 January 2005 (has links) (PDF)
Amorphous, hydrogenated carbon films (a-C:H) have been prepared in a PECVD device from methane and ethine as the source gases.The aim was to deposit films at high growth rates while keeping high hardness (25 ± 3 GPa). Hardness, hydrogen content and surface roughness were investigated dependent on the process conditions. Further investigation showed, that the mechanical properties of the a-C:H films are determined by the energy of the ions and the ratio between the film forming ion and the film forming neutral fluxes. On the basis of the collected data the optimal deposition conditions were determined and suggestions for further improvement of the deposition were made. / Amorphe, wasserstoffhaltige Kohlenstoffschichten (a-C:H) wurden mittels PECVD-Verfahren abgeschieden, wobei Methan und Ethin als Quellgase verwendet wurde. Ziel war dabei die Abscheidung der Schichten mit hohen Aufwachsraten unter Beibehaltung hoher Härten (25 ± 3 GPa). Härte, Wasserstoffgehalt und Oberflächenrauhigkeit der Schichten wurden in Abhängigkeit von den Prozeßbedingungen untersucht. Weitere Untersuchungen zeigten, daß die mechanischen Eigenschaften der a-C:H Schichten von der Energie der Ionen und dem Verhältnis der schichtbildenden Ionen- und Neutralteilchenflüsse bestimmt werden. Auf der Grundlage der gewonnenen Daten können die optimalen Abscheidebedingungen festgelegt, und Vorschläge zur weiteren Verbesserung der Schichtabscheidung gemacht werden.

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