This master thesis deals with the use of microfluidics for the purpose of microfluidic enzymatic reactor for drug screening. At first it considers the issue from a theoretical point of view – describes microfluidics as a newly developing and promising field of production of microfluidic devices, materials, biomedical applications and advantages and disadvantages of microfluidics overall. Furthermore, it focuses on an area of analytical utilization of enzymes within enzyme reactors. In the first part of the experimental section, conditions for the testing of enzymes of xenobiotics metabolism in the liver were optimized, namely the model of coumarin metabolism via the spectrofluorimetry method. The second part of the experimental work dealt with optimization of the fabrication conditions of microfluidic chips from OSTE (off-stoichiometry Thiol Ene) via the soft lithography method. Subsequently, the functionality of the produced chips was tested. Based on the results of both parts of the experimental work, an evaluation was carried out to assess the suitability of their interconnection for future research – screening of microsomal enzyme activity and model biotransformation of drugs within the channels of the fabricated devices.

Simple low-cost temperature feedback control loop was created, using personal computer as control and data acquisition element. It controlled the temperature inside mircowave pressure reactor. Medium in reactor tank (volume about 600 ml) was calorified by 1,8 kW magnetron, which power was driven by PSD controller. The PC- process interface was made by USB data acquisition modul UD128A8D. The utility program was written. It implemented PSD controller and data acquisition function. Furhtermore it implemented interface which enabled user to set the technological curve (time-temperature relation). The protocol of experiment was automatically stored to Micosoft Excel file before the program’s termination.

The thesis describes effect of long-time ageing on the microstructure and properties of the Eurofer´97 steel. The ferritic-martensitic reduced activation steel Eurofer´97 is candidate structural material for in-core components of proposed fusion reactors. Thesis is focused on examination and description of brittle-fracture behaviour of the steel. Properties of the steel were investigated in as-received state and state after long-time ageing. Detailed microstructure studies were carried out by means of optical and electron microscopy and also by means of quantitative electron microscopy. Mechanical properties were evaluated also in both states by means of hardness tetsing, tensile testing and Charpy impact testing. Fractography analysis of fracture surfaces was carried out on samples after Charpy impact testing.

The thesis deals with a project of a steam generator heated with liquid sodium. The first section describes some types of steam generators at nuclear power plants which have been projected or put into use. The next part presents a draft concept of the steam generator, solved by this work. The implementation of the steam generator module has been selected from several options, based on the thermal, hydraulic and stress calculations and on the chosen criteria. The conclusion of this thesis deals with the evaluation of the final solution in terms of nuclear safety and technical solutions, and compares this solution to similar projects following various criteria.

This master’s thesis deals with a design of Na-CO2 heat exchanger. There is a comparison of shell and tube heat exchanger with PCHE in the first part. Further the shell and tube heat exchanger with internally finned tubes was chosen as the basic conception. There was performed an optimization of construct and operations parameters for this concept. The optimization was performed on the basis of thermal and hydraulic calculations. Further there were performed calculations for ensuring of safe operation of the heat exchanger. The conclusion of the diploma thesis deals with comparison of the designed heat exchanger with similar projects.

The objective of this diploma thesis is to assess the suitability of a small nuclear reactor for the purpose of heat supply in small towns and cities. First, all the heat demands of these towns and cities are analysed. Then, a small nuclear reactor to serve these needs is designed and a computational model for burn-up fuel is created. The thesis aims to propose a design of a new heat exchanger. Economic and environmental criteria are taken into account as well and including safety measures. The outcome of this thesis is an evaluation of the whole concept with respect to potential future implementation.

Frågor kring kärnkraftverk har alltid varit ett omdiskuterat ämne. Kärnkraftens betydelse varierar stort mellan olika länder. Av 441 reaktorer i världen tillhör 10 av dem till Sverige. Kärnkraftverk i Oskarshamn är en av dem. Företaget OKG har beslutat att genomföra en övergripande utredning kring olika konstruktionstyper av reaktorinneslutningar med detta examensarbete. Arbetet begränsas till att göra en litteraturundersökning. En viss genomgång av både nationella och internationella rapporter har gjorts. Det primära syftet med detta examensarbete är uppdelat i två huvuddelar. Den första delen av utredningen visar olika konstruktionstyper av reaktorinneslutning i hela världen. Den andra delen visar de reaktorinneslutningarna som har en liknande konstruktion som på OKG d.v.s. betong som är förspänd med cementinjekterade spännkablar. En liknande konstruktion finns bl.a. i Finland och Frankrike. Vi har också diskuterat kontroller för andra konstruktionstyper där spännkablarna är omgivna av luft eller fettinjekterade. I utredningen redovisas en del inträffade skador och incidenter i Svenska och utländska kärnkraftverk reaktorer. Företaget har två övriga frågeställningar som undersöktes i senare skedet av arbetsgång. Spännkrafter minskar med tiden på grund av krympning och krypning i spännarmerade konstruktioner vilket påverkar säkerheten av konstruktionen negativt. Som en del av detta arbete utfördes undersökningar om det finns metoder att bestämma spännkrafter där spännkablarna inte är åtkomliga. I det slutliga skedet av utredningen undersöktes metoder som Trafikverket följer för att kontrollera sina broar d.v.s. utföra huvudinspektioner/ besiktningar. Huvudsyftet av examensarbetet har uppfyllts men vissa delar är begränsade på grund av mesta informationer av olika kärnkraftverk är konfidentiella och inte tillgängliga på nätet. Och alla våra undersökningar var webbaserade som innebär att vi hade inte möjlighet att hitta rätt informationer direkt från webben. Samtidigt kontakta de olika utländska kärnkraftverken var inte så lätt på kort varsel. Strålsäkerhetsmyndighet (SSM) hjälpte oss att få kontaktinformation av 3 olika länder. I slutet av rapporten ges analys och diskussion kring utredningen. / Questions regarding Nuclear Power Plants have always been a controversial subject. Nuclear power's importance varies between countries. Of the 441 reactors in the world 10 of them belongs to Sweden. Oskarshamn Nuclear Power Plant is one of them. OKG has decided to conduct a comprehensive investigation of this thesis work around some issues. The main purpose of this thesis work is to make a literature investigation about bracing cables in reactor containment. A specific review of national and international reports has been made and formed a collective basis with the company issues. The introductory part of this thesis is divided into two main parts. The first review of this report considers different structural types of reactor containment in the world. Most nuclear reactors are enclosed by a pre-stressed concrete containment and some have steel reactor containment. In both Sweden and Finland, the enclosure is designed as a concrete cylinder, which is pre-stressed both vertically and horizontally. The second review describes about those reactor containments, which has a similar construction to the OKG (the tendons are placed in the casing that after chucking was injected with cement mortar). A similar construction can be found in Finland and France. The investigation also reveals the damage and accidents in Swedish and foreign nuclear power reactors in recent years. Furthermore, company has two other issues, which were implemented in the later stages of the work. Due to shrinkage and creep in the concrete and relaxation in the tendons, the prestressed capacity decreases with time which affects the structure negatively. The objective of this thesis is to investigate if there are methods for determining tensile forces where the tendons are not accessible. Methods are divided into two different types: one is cement grouting method, same as OKG and another one is oil-injection method. The final review of report is to investigate about TRAFIKVERKET methods to check/inspection the bridges. It can be concluded that the main expectations of this thesis has been fulfilled but some parts are still missing due to limitation of proper information. To contact with the various foreign nuclear power plants was not so easy within this short time. All our experiments were web-based and there were many confidential matters which is unreachable. Swedish Radiation Safety authority (SSM) helped us to get contact details of 3 different countries. The discussions about the reviews are summarized at the end of the report.

Målen med denna uppsats var att studera två aspekter av temperatur inducerade spänningar med referens till kärnkraftsanläggningen Forsmark F1. Ena aspekten inkluderade den termiska kyleffekten av de ventilerade spännkabelrören i cylinderväggen. Det var av intresse att studera om den termiska kyleffekten av de ventilerade spännkabelrören hade en positiv global effekt som var relevant att beakta i globala tredimensionella modeller. Den andra aspekten inkluderade inverkan av ingjutet stål i den övreringplattan. Med syftet att studera om ingjutet stål var en aspekt som ansågs nödvändigt att beakta i transienta analyser.   Huvudanalyseringsverktyg var finita element metoden (FEM), genom användning av det kommersiellt tillgängliga finita element programmet SOLVIA.   Inverkan av den termiska kyleffekten av de ventilerade spännkabelrören indikerade en spännings reducerande effekt, med reducerade zoner av sprucken betong i cylinderväggen vid förhöjda temperaturer. Inverkan av ingjutet stål indikerade ökade temperaturskillnader mellan det ingjutna stålet och den omgivande betongen, med sprucken betong lokalt mellan stålet och betongen vid förhöjda temperaturer. Den termiska kyleffekten av de ventilerade spännkabelrören ansågs relevant att beakta i globala tredimensionella modeller. Ingjutet stål ansågs vara nödvändigt att inkludera i transienta analyser. / The aims of this thesis were to study two aspects of temperature induced stresses with reference to the nuclear power plant Forsmark F1. One aspect included the thermal cooling effect of the ventilated tendon ducts in the cylinder wall. It was of interest to study if the thermal cooling effect of the ventilated tendon ducts had a positive global effect which was relevant to consider in global three-dimensional models. The other aspect included the influence of embedded steel in the upper ring slab. With the purpose to study if embedded steel was an aspect that was considered necessary to include in transient analyses.   The used main analysis tool was the finite element method (FEM), through the use of the commercially available finite element program SOLVIA.   The influence of the thermal cooling effect of the ventilated tendon ducts indicated a stress reducing effect, with reduced cracked concrete in the cylinder wall at elevated temperatures. The influence of embedded steel indicated increased temperature differences between the embedded steel and the surrounding concrete, with cracked concrete locally between the steel and the concrete at elevated temperatures. The thermal cooling effect of the ventilated tendon ducts was considered relevant to consider in global three-dimensional models. Embedded steel was considered necessary to include in transient analyses.

Cílem práce bylo vytvořit základní koncept integrovaného výměníku tepla pro solí chlazený reaktor vyvíjený společností Terrestrial Energy s využitím programu Promex. První kapitola se zabývá historií a současnou situací v oblasti výzkumu malých modulárních reaktorů chlazených fluoridovými solemi. Ve druhé kapitole jsou popsány vlastnosti fluoridových solí a konstrukčních materiálů. Poslední kapitola se zabývá simulací tepelného výměníku pomocí programu Promex, validací modelu, transformací protiproudého výměníku na výměník s U trubkami a vizualizací výměníku s použitím CAD Invetoru.

In this thesis, ammonia (NH3) decomposition was assessed as a fuel processing technology for producing on-demand hydrogen (H2) for portable and distributed fuel cell applications. This study was motivated by the present lack of infrastructure to generate H2 for proton exchange membrane (PEM) fuel cells. An overview of past and recent worldwide research activities in the development of reactor technologies for portable and distributed hydrogen generation via NH3 decomposition was presented in Chapter 2. The objective was to uncover the principal challenges relating to the state-of-the-art in reactor technology and obtain a basis for future improvements. Several important aspects such as reactor design, operability, power generation capacity and efficiency (conversion and energy) were appraised for innovative reactor technologies vis-à-vis microreactors, monolithic reactors, membrane reactors, and electrochemical reactors (electrolyzers). It was observed that substantial research effort is required to progress the innovative reactors to commercialization on a wide basis. The use of integrated experimental-mathematical modelling approach (useful in attaining accurately optimized designs) was notably non-existent for all reactors throughout the surveyed openliterature. Microchannel reactors were however identified as a transformative reactor technology for producing on-demand H2 for PEM cell applications. Against this background, miniaturized H2 production in a stand-alone ammonia-fuelled microchannel reactor (reformer) washcoated with a commercial Ni-Pt/Al2O3 catalyst (ActiSorb® O6) was demonstrated successfully in Chapter 3. The reformer performance was evaluated by investigating the effect of reaction temperature (450–700 °C) and gas-hourly-space-velocity (6 520–32 600 Nml gcat -1 h-1) on key performance parameters including NH3 conversion, residual NH3 concentration, H2 production rate, and pressure drop. Particular attention was devoted to defining operating conditions that minimised residual NH3 in reformate gas, while producing H2 at a satisfactory rate. The reformer operated in a daily start-up and shut-down (DSS)-like mode for a total 750 h comprising of 125 cycles, all to mimic frequent intermittent operation envisaged for fuel cell systems. The reformer exhibited remarkable operation demonstrating 98.7% NH3 conversion at 32 600 Nml gcat -1 h-1 and 700 °C to generate an estimated fuel cell power output of 5.7 We and power density of 16 kWe L-1 (based on effective reactor volume). At the same time, reformer operation yielded low pressure drop (<10 Pa mm-1) for all conditions considered. Overall, the microchannel reformer performed sufficiently exceptional to warrant serious consideration in supplying H2 to low-power fuel cell systems. In Chapter 4, hydrogen production from the Ni-Pt-washcoated ammonia-fuelled microchannel reactor was mathematically simulated in a three-dimensional (3D) CFD model implemented via Comsol Multiphysics™. The objective was to obtain an understanding of reaction-coupled transport phenomena as well as a fundamental explanation of the observed microchannel reactor performance. The transport processes and reactor performance were elucidated in terms of velocity, temperature, and species concentration distributions, as well as local reaction rate and NH3 conversion profiles. The baseline case was first investigated to comprehend the behavior of the microchannel reactor, then microstructural design and operating parameters were methodically altered around the baseline conditions to explore the optimum values (case-study optimization). The modelling results revealed that an optimum NH3 space velocity (GHSV) of 65.2 Nl gcat -1 h-1 yields 99.1% NH3 conversion and a power density of 32 kWe L-1 at the highest operating temperature of 973 K. It was also shown that a 40-μm-thick porous washcoat was most desirable at these conditions. Finally, a low channel hydraulic diameter (225 μm) was observed to contribute to high NH3 conversion. Most importantly, mass transport limitations in the porouswashcoat and gas-phase were found to be negligible as depicted by the Damköhler and Fourier numbers, respectively. The experimental microchannel reactor produced 98.2% NH3 conversion and a power density of 30.8 kWe L-1 when tested at the optimum operating conditions established by the model. Good agreement with experimental data was observed, so the integrated experimental-modeling approach used here may well provide an incisive step toward the efficient design of ammonia-fuelled microchannel reformers. In Chapter 5, the prospect of producing H2 via ammonia (NH3) decomposition was evaluated in an experimental stand-alone microchannel reactor wash-coated with a commercial Cs-promoted Ru/Al2O3 catalyst (ACTA Hypermec 10010). The reactor performance was investigated under atmospheric pressure as a function of reaction temperature (723–873 K) and gas-hourly-space-velocity (65.2–326.1 Nl gcat -1 h-1). Ammonia conversion of 99.8% was demonstrated at 326.1 Nl gcat -1 h-1 and 873 K. The H2 produced at this operating condition was sufficient to yield an estimated fuel cell power output of 60 We and power density of 164 kWe L-1. Overall, the Ru-based microchannel reactor outperformed other NH3 microstructured reformers reported in literature including the Ni-based system used in Chapter 3. Furthermore, the microchannel reactor showed a superior performance against a fixed-bed tubular microreactor with the same Ru-based catalyst. Overall, the high H2 throughput exhibited may promote widespread use of the Ru-based micro-reaction system in high-power applications. Four peer-reviewed journal publications and six conference publications resulted from this work. / PhD (Chemical Engineering), North-West University, Potchefstroom Campus, 2015