The need for electric power across the globe is ever increasing, as is the need to produce electricity in a sustainable method that does not emit CO2 into the atmosphere. A proposed technology for efficiently capturing CO2 while producing electricity is pressurized oxy-combustion (POC). The objective of this work is to design, build, and demonstrate a burner for a 20 atmosphere oxy-coal combustor. Additionally, working engineering drawings for the main pressure vessel and floor plan drawings for the main pressure vessel, exhaust, and fuel feed systems were produced. The POC reactor enables the development of three key POC technologies: a coal dry-feed system, a high pressure burner, and an ash management system. This work focuses on the design of a traditional diffusion flame burner and the design of the main reactor. The burner was designed with the intent to elongate the flame and spread heat flux from the reacting fuel over a longer distance to enable low CO2 recycle rates. This was done by matching the velocities of the fuel and oxidizer in the burner to minimize shear between incoming jets in order to delay the mixing of the coal and oxygen for as long as possible. A spreadsheet model was used to calculate the jet velocities and sizes of holes needed in the burner, comprehensive combustion modeling was outsourced to Reaction Engineering International (REI) to predict the performance of burner designs. Using the guidance of the modeling results, a burner design was selected and assembled. The burner consists of a center tube where the primary fuel will flow, two concentric secondary tubes making an inner and an outer annulus, and eight tertiary lances. The burner and reactor are ready to be tested once issues involving the control system are resolved. Measurements that will be taken once testing begins include: axial gas and wall temperature, radiative heat flux, outlet gas temperature, and ash composition.

One of the challenges facing engineers is to provide clean, sustainable, affordable and reliable electricity. One of the major pollutants associated with coal combustion is CO2. A proposed technology for efficiently capturing CO2 while producing electricity is pressurized oxy-combustion (POC). The first objective of this work is to design, build and demonstrate an exhaust system for a 20 atmosphere oxy-coal combustor. The second objective of this work is to design and build mounts for a two-color laser extinction method in the POC. The POC reactor enables the development of three key technologies: a coal dry-feed system, a high pressure burner, and an ash management system. This work focuses on cooling the flue gas by means of a spray quench and heat exchanger; controlling the reactor pressure and removing ash from the flue gas. Designs and models of each component in the exhaust systems are presented. Methods to test and assemble each system are also discussed. The spray quench flow rate was measured as a function of pump pressure. Theoretical models for the required amount of water in the spray quench, the flue gas composition, the length and number of tubes in the heat exchanger, and the cyclone collection efficiency are presented. The combined exhaust system is assembled and ready to be tested once issues involving the control system and burner are resolved.

Nanoelectromechanical systems (NEMS) play an important role in advancing high-precision sensing and high-speed computational applications due to their exceptional sensitivity and reduced size. This thesis explores the dynamic behaviors and vibrational properties of NEMS, focusing on coupled systems of molybdenum disulfide (MoS2) membrane and silicon nitride (SiNx) drumhead, and the effects of gas pressure on an MoS2 membrane resonator. Employing finite element simulations alongside theoretical modeling, the study thoroughly analyzes the coupling dynamics between MoS2 and SiNx resonators and investigates the vibrational responses of MoS2 membranes under pressure. Key achievements include the identification of vibrational modes, calculation of coupling constants, and comprehensive understanding of pressurized MoS2 membrane resonator behavior. These insights pave the way for enhancing NEMS applications in sensitive detection and resonant frequency modulation, significantly contributing to the field of nanotechnology and the development of advanced NEMS devices.

When a pressurized water reactor is operated for a sufficiently long period of time, a small number of fuel rods will develop ruptures in their claddings. These defects will leak volatile fission products into the primary coolant, including radioactive iodine. During steady-state operation of the reactor a low level iodine activity is thus present in the coolant. Initiation of a down-power or up-power transient will result in a rapid climb in the activity of the iodine which peaks at a level much higher than the initial activity. After this time the activity levels out and then slowly begins to decay back to a new steady-state level. This phenomenon is termed "iodine spiking.” A physical model of this process is sought for explanatory and predictive purposes. A FORTRAN code is developed that solves a system of differential equations which describe the production and removal of iodine in the fuel, gap region, and primary coolant. As much physics as possible is employed but some complicated diffusion processes have led to the utilization of certain parametric results obtained from empirical data. Actual PWR spiking data is also employed for comparison and adjustment of the model. It is the goal of this project to be able to utilize the model for predictive analysis· during actual PWR operation so that a better understanding of iodine spiking behavior can be obtained. / Master of Science

Increased conversion ratios and burnup can be achieved by mechanically changing the fuel-to-water volume ratio of a reactor over the core lifetime. As the fuel-to-water ratio decreases, the neutron spectrum softens, thereby increasing core reactivity. Proposed mechanical spectral shift reactors utilize this concept. RFD-1, a 1-dimensional, 4-group code was developed to compute fuel burnup cycles for spectral shift reactors. The code calculates burnup for a triangular core lattice having a beginning fuel to water ratio as high as 1.30. Core shutdown occurs at a fuel to water ratio of 0.50. The microscopic cross sections were obtained through use of the VIM code and tabulated for use in RFD-1 as a function of fuel to water ratio and burnup time. The fission product group cross sections were developed using the VIM and TOAFEW codes. The flexibility of RFD-1 allows the user to study a wide variety of possible core configurations. Results of RFD-1 show that increased conversion and burnup, using lower initial enrichments than that of standard Pressurized Water Reactors, result for mechanical spectral shift designs. The next step is to study specific spectral shift designs in greater detail. The RFD-1 code could be improved primarily through refinements in its cross section data tables. / Master of Science

A structure comprised of two arches that lean against each other at the apex is considered. The arches are thin shells with internal pressure. This type of structure with solid arches has been used in bridges, such as the Gateway Arch Bridge in Columbus, Indiana, U.S.A., the Monongahela River Bridge in Pittsburgh, Pennsylvania, U.S.A., and a pedestrian bridge at the Pacific Tower in Paris, France. A series of leaning arches was incorporated in the frame of the Museum of the Moving Image, a temporary structure in London, England, during 1992-1994. Pressurized arch-shells made of a flexible material have been utilized as part of the framework for some transportable tent-like structures. The behavior of a pair of pressurized leaning arch-shells with various tilt angles, boundary conditions, and loads is investigated numerically. Several types of loads are considered, including uniformly-distributed vertical loads applied over all or half of the structure (representing snow), and wind loads on the structure. The arches are pinned or fixed to the ground. Deflections, vibrations, and stability of the structures are investigated using the finite element method. The effect of the tilt angle on the response is examined, and buckling may occur for some tilt angles under vertical loading. This type of structure has not been used widely, but may be effective for various applications. / Master of Science

No / Determining bioequivalence for solution pressurized metered dose inhalers (pMDI) is difficult because the critical characteristics of such products are poorly defined. The aim of this study was to elucidate the non-aerodynamic properties of the emitted aerosol particles from two solution pMDI products that determine their biopharmaceutical differences after deposition. Novel particle capture and analysis techniques were employed to characterize the physicochemical and biopharmaceutical properties of two beclomethasone dipropionate (BDP) products: QVAR and Sanasthmax. The BDP particles emitted from the Sanasthmax inhaler were discernibly different those emitted from QVAR in terms of size (50% larger, less porous), solid state (less crystalline) and dissolution (20-fold slower). When deposited onto the surface of respiratory epithelial cell layers, QVAR delivered ∼50% more BDP across the cell layer in 60 min than Sanasthmax. Biopharmaceutical performance was not attributable to individual particle properties as these were manifold with summative and/or competing effects. The cell culture dissolution− absorption model revealed the net effect of the particle formed on drug disposition and was predictive of human systemic absorption of BDP delivered by the test inhalers. This illustrates the potential of the technique to detect the effect of formulation on the performance of aerosolized particles and contribute to assessment of bioequivalence. / This work was in part funded by a grant from the Safety and Environmental Assurance Centre, Unilever Colworth, U.K. Particle sizing was performed by Steve Ingham, Institute of Pharmaceutical Science, King’s College London.

The Multi-Application Small Light Water Reactor (MASLWR) is a small natural circulation pressurized light water reactor design that was developed by Oregon State University (OSU) and Idaho National Engineering and Environmental Laboratory (INEEL) under the Nuclear Energy Research Initiative (NERI) program to address the growing demand for energy and electricity. The MASLWR design is geared toward providing electricity to small communities in remote locations in developing countries where constructions of large nuclear power plants are not economical. The MASLWR reactor is designed to operate for five years without refueling and with fuel enrichment up to 8 %. In 2003, an experimental thermal hydraulic research facility also known as the OSU MASLWR Test Facility was constructed at Oregon State University to examined the performance of new reactor design and natural circulation reactor design concepts. This thesis is focused on the thermal hydraulics analysis and fuel performance analysis of the MASLWR prototypical cores with fuel enrichment of 4.25 % and 8 %. The goals of the thermal hydraulic analyses were to calculate the departure nucleate boiling ratio (DNBR) values, coolant temperature, cladding temperature and fuel temperature profiles in the hot channel of the reactor cores. The thermal hydraulic analysis was performed for steady state operation of the MASLWR prototypical cores. VIPRE Version 01 is the code used for all the computational modeling of the prototypical cores during thermal hydraulic analysis. The hot channel and hot rod results are compared with thermal design limits to determine the feasibility of the prototypical cores. The second level of analysis was performed with a fuel performance code FRAPCON for the limiting MASLWR fuel rods identified by the neutronic and thermal hydraulic analyses. The goals of the fuel performance analyses were to calculate the oxide thickness on the cladding and fission gas release (FGR). The oxide thickness results are compared with the acceptable design limits for standard fuel rods. The results in this research can be helpful for future core designs of small light water reactors with natural circulation. / Graduation date: 2012

Thesis (Nucl.E.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1981. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE. / Includes bibliographical references. / by James North Loomis. / Nucl.E.

Innerhalb des Vorhabens wurde ein ATHLET-CD-Eingabedatensatz für einen generischen deutschen DWR vom Typ KONVOI entwickelt. Das ATHLET-CD-Modell wurde für die Simulation schwerer Störfälle aus den Störfallkategorien Station Blackout (SBO) und Kühlmittelverluststörfällen mit kleinen Lecks (SBLOCA) eingesetzt. Dabei ist die vollständige Störfalltransiente für den Zeitbereich zwischen dem einleitenden Ereignis bis zum Versagen des Reaktordruckbehälters (RDB) abgedeckt und alle wesentli-chen Phänomene schwerer Störfällen werden abgebildet: Beginn der Kernaufheizung, Spaltproduktfrei-setzung, Aufschmelzen von Brennstoff- und Absorbermaterialien, Oxidationsprozesse mit Freisetzung von Wasserstoff, Verlagerung von geschmolzenem Material, Verlagerung in das untere Plenum, Schä-digung und Versagen des RDB. Das Modell wurde für die Analyse möglicher präventiver und mitigativer Notfallmaßnahmen für SBO und SBLOCA angewandt. Dafür wurden die Notfallmaßnahmen primärseitige Druckentlastung (PDE), primärseitiges Einspeisen mit mobilen Pumpensystemen sowie für SBLOCA das verzögerte Einspeisen der kaltseitigen Druckspeicher untersucht und die Eigenschaften und Einleitekriterien der Maßnahmen variiert. Es wurden die Zeitverläufe der Unfallszenarien analysiert und die verbleibenden Zeitspannen für die Einleitung zusätzlicher Maßnahmen ermittelt. Für ein SBO-Szenario mit PDE wurde für die Frühphase der Transiente (bis zum Beginn der Kernschmelze) eine Unsicherheits- und Sensititvitätsanalyse durchgeführt. Zusätzlich wurde für ein SBLOCA-Szenario ein Code-zu-Code-Vergleich zwischen ATHLET-CD und dem Störfallcode MELCOR erarbeitet.