In-situ Generation and Grain Growth of Ceo2 Nanocrystals in AC/DC Electrical Fields

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High temperature measurements and condensed matter analysis of the thermo-physical properties of ThO2

Values are presented for thermal conductivity, specific heat, spectral and total hemispherical emissivity of ThO2 (a potential nuclear fuel material) in a temperature range representative of a nuclear accident - 2000 K to 3050 K. For the first time direct measurements of thermal conductivity have been carried out on ThO2 at such high temperatures, clearly showing the property does not decrease above 2000 K. This could be understood in terms of an electronic contribution (arising from defect induced donor/acceptor states) compensating the degradation of lattice thermal conductivity. The increase in total hemispherical emissivity and visible/near-infrared spectral emissivity is consistent with the formation of donor/acceptor states in the band gap of ThO2. The electronic population of these defect states increases with temperature and hence more incoming photons (in the visible and near-infrared wavelength range) can be absorbed. A solid state physics model is used to interpret the experimental results. Specific heat and thermal expansion coefficient increase at high temperatures due to the formation of defects, in particular oxygen Frenkel pairs. Prior to melting a gradual increase to a maximum value is predicted in both properties. These maxima mark the onset of saturation of oxygen interstitial sites

Innovative preparation route for uranium carbide using citric acid as a carbon source

The preparation of uranium carbide (UC) by carbothermal reduction and its sintering into dense pellets by conventional means require high temperatures for long periods. We have developed a preparation route yielding fine UC powder with significantly increased sinterability. At first, a mixture of nanocrystalline UO2 embedded in amorphous carbon (nano-UO2/C) was obtained by thermal decomposition of a gel containing solubilised uranyl nitrate and citric acid. Later, the nano-UO2/C powder was treated in a conventional furnace or in a modified spark plasma sintering facility at elevated temperatures (≥1200°C) in order to obtain uranium carbide powder. The effects of initial composition, temperature, gas/vacuum atmosphere and the overall reaction kinetics are reported

Battery Management System Design (BMS)

Diplomová práce je zaměřena na návrh systému pro řízení akumulátorů. Práce se v první části zabývá druhy akumulátorů, a výběrem vhodného typu. V druhé části je práce zaměřena na bateriový management. V této kapitole je popis bateriového management systému, jeho rozdělení a funkce. Další kapitola je zaměřena na návrh systému pro řízení akumulátorů. Návrh obsahuje aktivní i pasivní vyvažování akumulátorů. Je rozdělen na tři desky plošných spojů, které jsou vzájemně propojeny. Poslední kapitola diplomové práce je věnovaná testování systému. Kde jsou rozebrány chyby návrhu, jeho vylepšení a testování balancérů.ObhájenoThe thesis is focused on the design of a battery control system. The first part of the work deals with the types of batteries, and the choice of the appropriate type. The second part is focused on battery management. This chapter describes the battery management system, its division and functions. Next chapter is focused on the design of the battery control system. The design includes both active and passive battery balancing. It is divided into three printed circuit boards that are interconnected. Last chapter of the thesis is devoted to system testing where design errors, design improvements and balancer testing are discussed

Identification of Benefits and Costs of Mandatory Project

Import 02/11/2016Předmětem bakalářské práce „Identifikace přínosů a nákladů mandatorního projektu“ je příprava podkladů pro komplexní posouzení investičního projektu realizovaného v Elektrárně Počerady, a. s. za účelem snížení emisí oxidů dusíku pod hodnotu 200 mg/Nm3. V teoretické části jsou popisovány metody hodnocení investičních projektů, technologie výroby elektrické energie, vzniku NOx a metody jejich snižování. Praktická část se zabývá popisem vlastního projektu a klade si za cíl shromáždit podklady pro možnost kvantifikace a posouzení dopadů realizace nejen na podnik samotný, ale i na jeho okolí za pomocí vhodných metod.The aim of this bachelor thesis „Identification of costs and benefits of mandatory project“ is preparation of a basis for complex consideration of an investment project realised in Pocerady power station in order to reduction nitrogen oxides emissions under the value 200 mg/Nm3. The theoretical part of the work presents methods of appreciation of investment projects, technologies of electrical energy production, formation of NOx and methods of their reduction. The practical part deals with the description of the project itself and aims to collect a basis for the possibility of quantification as well as considers the impact of the project’s realisation not only on the company itself but on its environment with help of the appropriate methodsPrezenční545 - Institut ekonomiky a systémů řízenívýborn

Material effect in nuclear Fuel - Coolant interaction: Structural characterization of the steam explosion debris and solidification mechanism

Thesis Abstract This thesis has been performed under co-tutelle supervision between Charles University in Prague (Czech Republic) and Strasbourg University (France). It also profited from the background and cooperation of Institute of Inorganic Chemistry Academy of Science of the Czech Republic and French Commission for Atomic and Alternative energies (CEA Cadarache, France). Results of the work contribute to the OECD/NEA project Serena 2 (Program on Steam Explosion Resolution for Nuclear Applications). Presented thesis can be classed in the scientific field of nuclear safety and material science. It is aimed on the so-called "molten nuclear Fuel - Coolant Interaction" (FCI) that belongs among the recent issues of the nuclear reactor severe accident R&D. During the nuclear reactor melt down accident the melted reactor load can interact with the coolant (light water). This interaction can be located inside the vessel or outside in the case of vessel break-up. These two scenarios are commonly called in- and ex-vessel FCI and they differ in the conditions such as initial pressure of the system, water sub-cooling etc. The Molten fuel - coolant interaction can progress into thermal detonation called also "steam explosion" that can challenge the reactor or containment integrity. Recent experiments have shown that..

Selected nanoparticles systems and their physical and chemical properties

Department of Inorganic ChemistryKatedra anorganické chemiePřírodovědecká fakultaFaculty of Scienc