Possible fuel cycle scenarios for a helium-cooled, sub-critical, fast reactor with a fusion neutron source for the transmutation of spent nuclear fuel have been analyzed. The transmutation rate was set by the 3000MWth fission power output. The primary objective was to achieve greater than 90% burn of the transuranic (TRU) fuel obtained from spent nuclear fuel. A secondary objective was to examine the possibility of achieving this deep burn without reprocessing after initial fabrication of the TRU into coated particle TRISO fuel. Four sets of 5-batch fuel cycle scenarios, differing in the constraints imposed on the beginning of cycle (BOC) k-eff and the end of cycle (EOC) neutron source strength (characterized by the fusion neutron source power level), were evaluated. In scenario A, BOC k-eff was required to be 0.95 and EOC Pfus less than 200 MWth was required. In scenario B, the restriction was removed to allow less reactive BOC fuel loadings, while the 200 MW upper limit on EOC Pfus was retained. It was found that the primary objective of greater than 90% TRU burn-up could be achieved by repeatedly reprocessing the TRISO TRU fuel particles to remove fission products and add fresh TRU makeup at the end of each 5-batch burn cycle, without needing to increase the fusion neutron source power above 100 MWth when the BOC k-eff is restricted to 0.95. The secondary objective of obviating processing could only be accomplished when the restriction was removed and recycling was employed or when both EOC Pfus and BOC k-eff restrictions were removed in a single-pass deep burn fuel cycle. In scenario C, with both the BOC k-eff limit and the fusion power limit unrestricted, greater than 90% TRU burn-up was achieved without reprocessing the TRISO TRU fuel particles, which could then be buried intact in a high-level waste repository, but a neutron source rate of 3370 MWth was required. In scenario D, with only the BOC k-eff limit unrestricted, greater than 90% TRU burn-up was achieved without reprocessing by the continuous recycle of TRISO particles through the reactor.

Experiments were conducted in a free-surface, re-circulating water channel to determine the dependence of spanwise flow uniformity in the near wake of a circular cylinder on the end conditions using Particle Image Velocimetry. The Reynolds number was 10,000. The end conditions consisted of plates with different leading edge geometries and configurations. A cylinder bounded by two endplates with sharp leading edge geometry generated the most uniform near wake. The horseshoe vortex dynamics in the cylinder/ wall and cylinder/endplate junctions were also studied. Upstream flow separation significantly altered the behavior of the horse shoe vortices. Periodic horse shoe vortex oscillation was found for experiments with the upstream flow attached; this periodic oscillation was disrupted with the presence of upstream flow separation. The endplate leading edge distance was also investigated. The oscillation frequency of the horse shoe vortex system was found to decrease with increasing leading edge distance.

Experiments were conducted in a free-surface, re-circulating water channel to determine the dependence of spanwise flow uniformity in the near wake of a circular cylinder on the end conditions using Particle Image Velocimetry. The Reynolds number was 10,000. The end conditions consisted of plates with different leading edge geometries and configurations. A cylinder bounded by two endplates with sharp leading edge geometry generated the most uniform near wake. The horseshoe vortex dynamics in the cylinder/ wall and cylinder/endplate junctions were also studied. Upstream flow separation significantly altered the behavior of the horse shoe vortices. Periodic horse shoe vortex oscillation was found for experiments with the upstream flow attached; this periodic oscillation was disrupted with the presence of upstream flow separation. The endplate leading edge distance was also investigated. The oscillation frequency of the horse shoe vortex system was found to decrease with increasing leading edge distance.

Energy saving in coal power plants is a popular topic in present days with the global energy crisis. Internal electricity demand or auxiliary power consumption is an energy portion related with equipment supportive to the main equipment, which is unavoidable but with a proper investigation, some amount of this energy can be saved either by introducing thermally efficient auxiliary equipment or improving efficiencies of available equipment. Out of the various auxiliary equipment, the driving motor of boiler feed pump is the largest power consumer of internal electricity demand in 3x300 MW sub-critical Lakvijaya Power Station in Sri Lanka. So it is obvious that prime movers of feed pumps could be contributed for a large percentage of the losses. So it was decided to find out how to minimize the losses related to Boiler Feed Pump (BFP) system using small steam turbine to drive the BFP. The widely used alternatives for the BFP drivers are condensing type and back pressure type steam turbines. Eleven (11) different configurations of Condensing type, back pressure type and also extraction back pressure type turbines were considered and software programs for each configuration were implemented using Engineering Equation Solver (EES) software. The considered configurations are different to each other by inlet steam thermodynamic parameters, steam flow rate, exhaust thermodynamic steam parameters and intermediate extraction parameters etc. Thermodynamic analysis ended up with interesting solutions while all the configurations are giving improved efficiencies than existing electrical motor driven mode. But some of them had not improved their net output and hence there were no gain in net generator power output although the efficiencies are higher. Out of other configurations with improved net output and efficiency, the case with back pressure turbine arranged parallel to the HP turbine had the highest net output gain with better improvement in efficiency without changing the input power to the boiler. Considering the CO2 , SOx and NOx emissions, it was cleared that power plant with suggested BFP modes will give more clean energy than existing power plant. Considering the partial loads behavior it was observed that power plant with Back pressure turbine, steam extracted from HP turbines inlet for prime movers of boiler feed pumps is more thermodynamically economical than existing power plant. Annual financial saving with BFP configurations with positive net output gain and zero boiler input gain were calculated and it will be in between 0.46 and 2.72 UDS million / Year.

La lignine est une macromolécule, constituant de la biomasse lignocellulosique, qui est composée d’unités propylphénoliques. Cette matière est produite par l’industrie papetière en tant que coproduit de la cellulose. Actuellement, sa valorisation se limite en grande partie à des applications énergétiques. Or, la lignine peut être une source alternative de phénols si elle est dépolymérisée efficacement. Ce travail porte sur la transformation de la lignine en synthons aromatiques dans l’eau et en mélange eau-alcools en conditions sous-critique (225°C et 40-80 bar). Dans un premier temps, des études de conversion sont réalisées en réacteur fermé en utilisant l’eau comme solvant sur une lignine Kraft en présence de catalyseurs (Pt, Pd, Ru sur Al2O3,TiO2, ZrO2), le catalyseur Pd/ZrO2 nous a permis d’obtenir un rendement en phénols identifiés de 2%en 3 heures. Afin d’améliorer la conversion de la lignine en minimisant les réactions de condensations entre unités phénoliques, l’eau est remplacée par un mélange eau/alcool (éthanol, méthanol, isopropanol). La combinaison eau/isopropanol sans catalyseur nous permet d’augmenter le rendement en phénols identifiés de 5%. Nous avons ensuite essayé d’appliquer notre approche en réacteur continu. Même si le mélange eau/isopropanol était le meilleur solvant en réacteur fermé, le passage en réacteur continu s’est avéré complexe par la formation de produits solides. L’utilisation d’un mélange eau/éthanol a permis d’éviter ce problème et un rendement en gaiacol jusqu’à 1% est obtenu. L’éthanol permet de stabiliser des synthons instables dans le milieu par alkylation et estérification / Lignin is a macromolecule comprising lignocellulosic biomass, and is composed of propylphenyl units. Lignin is produced in large amounts by the paper industry when cellulose is isolated from biomass. Currently, its value is largely limited to source of energy and heat in recovery boilers. Nonetheless lignin can be an alternative source of aromatics if depolymerized effectively. The present work focuses on the transformation of lignin into aromatic building blocks using sub-critical water and mixtures of water/alcohols (225°C and 40-80 bar). Preliminary studies were carried out in a batch reactor; water was used as a solvent for the conversion of a Kraft lignin in the presence of catalysts (Pt, Pd, Ru on Al2O3, TiO2, ZrO2). The Pd/ZrO2 catalyst gave the highest yield of identified phenols with 2% in 3 hours. To improve the conversion of the lignin by minimizing condensation reactions between phenolic units, the water was replaced with a mixture water/alcohol (ethanol, methanol, isopropanol). The combination water/isopropanol without catalyst allowed us to increase the yield of identified phenols to 5%. The results obtained in batch reactor were extrapolated to a trickle-bed reactor. Even though the water/isopropanol mixture gave the best results in batch reactor, the implementation on a continuous reactor proved to be complex (formation of solids clogging the reactor). The use of a water/ethanol mixture prevented this problem and a yield in guaiacol of up to 1 % was obtained. Ethanol helps stabilize unstable building blocks by alkylation and esterification. This is evidenced by the NMR and chromatographic analysis

The research work described in this thesis, the environmentally friendly novel "Microwave Assisted Sub-Critical water (MASCW)" technology for particle engineering of active pharmaceutical ingredients and excipients was developed. The present novel technology MASCW process is described as green technology as water is used as the solvent medium and microwave energy as external source of heat energy for generation of a particle with different morphological and chemical properties. In MASCW process supersaturated solution of APIs is prepared by dissolving solute in water at high temperature and pressure conditions. Upon rapid and controlled cooling, based on the aqueous solubility of solute, solute/solvent concentration and dielectric constant of water rapid precipitation of API with narrow particle size distribution occurs. Using paracetamol (pca) as API moiety understanding of the mechanism of MASCW crystallisation process was investigated. The effect of different process and experimental parameters on crystallisation pathway and end product attributes were analysed. Correlation between the degree of supersaturation concentration of pca solution against temperature and pressure parameters was explained by generating binary phase diagram. Determination of polymorphic transformation pathway of pca from form I (stable) to form II metastable polymorphs in solution was analysed using Raman spectroscopy. The difference between conventional heating and subcritical treatment was explored by determining the change in the solvent dielectric constant and solubility of hydrophobic API molecule. Based on the process understanding results, this technology was further implemented to explore its application in generating phase pure stable and metastable cocrystal phase. Based on the solubility of API and cocrystal former congruent (CBZ/SAC, SMT/SAC, SMZ/SAC) and incongruent (CAF/4HBA) cocrystal pairs were selected. For the first time generation of anhydrous phase of CAF: 4HBA cocrystal in 1:1 stoichiometric ration was reported and generation of metastable cocrystal phase of CA CBZ: SAC form II was reported. The application of this technology was explored in generating phase pure metastable polymorph of paracetamol which retain higher compressibility and dissolution rate. The potential of MASCW micronisation process, theophylline is used as the model component to produce micro sized particles for pulmonary drug delivery system via dry powder inhaler (Foradil inhaler). The results demonstrate that the THF particles generated using MASCW process displayed greater aerodynamic performance compared to conventional spray-dried THF sample. In the final chapter, synthesis of inorganic biomaterial (nano crystalline hydroxyapatite) was reported for the first time and the prospects of combining API like ibuprofen (IBU) with a biologically active component like nano-crystalline hydroxyapatite (HA) through hydrogen bonding was mechanistically explained using X-ray diffractometer and spectroscopic techniques.

Steel Catenary Riser (SCR) is a popular solution for a floating production facility in the deep and ultra-deep ocean. In the analysis of SCR, the behavioral characteristics are investigated to check the failure modes by assessing the magnitude and the frequency of the stress and strain which SCR goes through in time series. SCR is affected by the motions of connected floating production facility and exciting environmental loads. The driven force and motion of SCR has an interaction with seabed soil which represents the stiffness and friction force where SCR touches the seabed. Dynamic response of SCR is primarily caused by the coupled motion of floating structure. The displacement of floating structure is often large and fast enough to cause short cycles of negative and positive tension on SCR. The interaction between SCR and seabed is concentrated at the touchdown zone resulting into the compression and corresponding deformation of pipeline at the position. This paper presents models of floating production facilities and connected mooring lines and SCRs in 100-year hurricane environmental loads and seabed, focusing on the motional characteristics of SCR at the touchdown zone. In time series simulation, the model of SCR is first analyzed as a pipeline with indefinite elasticity so that the SCR does not fail even if the exciting loads exceed the property limit of SCR. Then the SCR design is manually checked using criteria for each failure mode to estimate the integrity.

Accurate determination of the pressure losses at the bit is very important for drilling practices in petroleum industry. In the literature, there are several studies on determination of the pressure losses. Major focus is concentrated on single phase drilling fluids, which is far from accurate estimation of pressure losses for multiphase fluids, i.e., fluids including a liquid and a gas phase, at the bit. Some of these models are valid for multiphase fluids, however, they are either valid for very high gas flow rates, or developed using very strong assumptions. This study presents a mathematical model for calculating bit hydraulics for gasified drilling fluids. The theory, which is valid for both sonic (critical) and subsonic (sub-critical) regimes, is based on the solution of the general energy equation for compressible fluid flow. The model is sensitive to changes in internal energy, temperature and compressibility. In addition, the model uses &ldquo / mixture sound velocity&rdquo / approach. A computer program is developed based on the proposed mathematical model. The program calculates pressure drop through a nozzle in subsonic flow region, and suggest flow rate if the calculated pressure drop values is in the sonic flow pressure ranges. The program has been run at reasonable field data. The results of the models have been compared with the results of existing models in the literature. The results show that the pressure losses through the bit can be estimated with a variation less than 9%. Also, it has been observed that bottom hole pressure, velocity of the liquid phase and nozzle size have a strong influence on bit pressure drop.

En vue de permettre l'incinération des déchets nucléaires à vie longue, les réacteurs sous-critiques pilotés par accélérateur, plus communément dénommés ADS (Accelerator Driven System), sont l'une des solutions envisagées. Afin de permettre le monitorage de la puissance et donc le pilotage de tels systèmes, de multiples méthodes d'extraction de la réactivité ont été développées pendant les soixante dernières années. La méthode « kprompt », dernière en date, a démontré de multiples avantages et avait donné d'excellents résultats lors de l'expérience MUSE-4 dans le début des années 2000. Cette méthode, reposant sur la détermination de la distribution du temps de vie de fission intergénération, ne nécessite pas l'accès à la configuration critique pour la calibration (comme dans la méthode MSM) mais également l'investigation des taux de comptage sur de longs temps (comme dans la méthode des Aires). Sa robustesse, vis-à-vis de plusieurs facteurs physico-chimico-géométriques, a été éprouvée et confirmée pour le cas de l'expérience GUINEVERE. Par comparaison des résultats obtenus avec les méthodes usuelles de détermination de la réactivité, nous avons réussi à appliquer la méthode « kprompt » de façon satisfaisante aux différentes expériences dynamiques que sont les PNS et les Beam Trips. Finalement, suite à cette transposition de la méthode « kprompt » avec succès à l'expérience GUINEVERE, l'étape suivante consistera en son application au démonstrateur de puissance que sera le projet MYRRHA. / In order to allow the incineration of the long-lived nuclear wastes, the sub-critical reactors, more commonly named ADS (Accelerator Driven System), is one of the proposed solutions. To allow the monitoring of the power and therefore the control of such systems, several methods, developed during the last sixty years, give the reactivity. The last in date method, called « kprompt » method, has demonstrated many advantages and gave excellent results during the MUSE-4 experiment in the early 2000s. This method, based on the determination of the intergeneration fission lifetime distribution, does not require the access to the critical configuration for calibration (as for the MSM method) and the investigation of the counting rate on long times (as for the Area method). Its robustness, regarding several physical-chemical-geometrical factors, was tested and confirmed in the case of the GUINEVERE experience. By comparing the results obtained with the usual methods of reactivity determination, we applied adequately the « kprompt » method to the different dynamical experiments, the so-called PNS and Beam Trips. Finally, following the successfully transposition of the « kprompt » method to the GUINEVERE experience, the next step, in its application, will be to the power demonstrator MYRRHA.

It is important for practical and legal reasons that water and sediments in disturbed areas around the mining operation should be controlled. The construction of a well-designed drainage system that controls erosion and thus restores the proper hydraulic function of the surface is one of the most important post-disturbance features which should be done as part of the mining activities. However, even with the best planning and design, unless proper construction practices are adapted; both the disturbed and reclaimed areas are very much likely to be susceptible to erosion, sedimentation and stability problems. In order to tackle the problem, guidelines on how to design and construct the drainage system should be well prepared. The main objective of this study was to prepare guidelines for the proper design, construction and monitoring of the water drainage management system in the study areas (Kankberg, Maurliden and Renström-Petiknäs). This report has analysed the results from the outcome of HEC-RAS software for the case study of the new ditch around the Maurliden mine site and integrated with different guidelines. Based on the results of the HEC-RAS, the most common problems in the drainage system have been identified. Moreover the thesis project identified important physical parameters such as cross-sections and slopes of the representative ditch which affect the function of the ditch in the study areas. Hydraulic parameters such as velocity which is very important for designing the type of lining and also Froude number which is very important in identifying the type of flow whether it is super-critical, critical or sub-critical were identified. The latter helps to select the type of guideline to be used between steep slope and mild slope.