Nuclear Engineering Commons^™

In-Situ Condition Monitoring Of Components In Small Modular Reactors Using Process And Electrical Signature Analysis, Victor Lollar

Pursuit - The Journal of Undergraduate Research at The University of Tennessee

Components in small modular reactors (SMRs) are located in a hazardous environment and must be monitored remotely. Electrical signature analysis (ESA) is a viable option for component monitoring as it can be implemented on-line away from the actual equipment. This research attempts to use both electrical signatures from a pump motor and process variables such as flow and pressure to effectively monitor reactor components. An experimental flow loop with pump health monitoring equipment and a data acquisition system was used for experiments. Process variables analyzed include pressure, flow rate, water level, and motor vibrations. The electrical signatures monitored were the …

Neutron Irradiation Effects On Domain Wall Mobility And Reversibility In Lead Zirconate Titanate Thin Films, Joseph T. Graham, Geoff L. Brennecka, Paulo Ferreira, Leo Small, David Duquette, Christopher Apblett, Sheldon Landsberger, Jon F. Ihlefeld

Nuclear Engineering and Radiation Science Faculty Research & Creative Works

The effects of neutron-induced damage on the ferroelectric properties of thin film lead zirconate titanate (PZT) were investigated. Two sets of PbZr_0.52Ti_0.48O₃ films of varying initial quality were irradiated in a research nuclear reactor up to a maximum 1 MeV equivalent neutron fluence of (5.16± 0.03) x 10¹⁵ cm^-2. Changes in domain wall mobility and reversibility were characterized by polarization-electric field measurements, Rayleigh analysis, and analysis of first order reversal curves (FORC). With increasing fluence, extrinsic contributions to the small-signal permittivity diminished. Additionally, redistribution of irreversible hysterons towards higher coercive fields was …

Self-Healing Of Ionomeric Polymers With Carbon Fibers From Medium-Velocity Impact And Resistive Heating, Vishnu Baba Sundaresan, Andrew Morgan, Matt Castellucci

Mechanical and Nuclear Engineering Publications

Self-healing materials science has seen significant advances in the last decade. Recent efforts have demonstrated healing in polymeric materials through chemical reaction, thermal treatment, and ultraviolet irradiation. The existing technology for healing polymeric materials through the aforementioned mechanisms produces an irreversible change in the material and makes it unsuitable for subsequent healing cycles. To overcome these disadvantages, we demonstrate a new composite self-healing material made from an ionomer (Surlyn) and carbon fiber that can sustain damage from medium-velocity impact and heal from the energy of the impact. Furthermore, the carbon fiber embedded in the polymer matrix results in resistive heating …

On Applications And Limitations Of One-Dimensional Capillarity Formulations For Media With Heterogeneous Wettability, T. M. Bucher, H. Vahedi Tafreshi

Mechanical and Nuclear Engineering Publications

Force-balance-based one-dimensional algebraic formulations that are often used in characterizing the capillarity of a multi-component system (e.g., predicting capillary height rise inporous media) are discussed. It is shown that such formulations fail to provide accurate predictions when the distribution of wetting (or non-wetting) surfaces is not homogeneous. A more general mathematical formulation is suggested and used to demonstrate that for media with heterogeneous wettability, hydrophilic (or hydrophobic) surfaces clustered in groups will have less contribution to the overall capillarity of the system.

Method And System For Scatter Correction In X-Ray Imaging, X. Wu, J. Hsieh, P. Sainath, Xin Liu

Nuclear Engineering and Radiation Science Faculty Research & Creative Works

Approaches for deriving scatter information using inverse tracking of scattered X-rays is disclosed. In certain embodiments scattered rays are tracked from respective locations on a detector to a source of the X-ray radiation, as opposed to tracking schemes that proceed from the source to the detector. In one such approach, the inverse tracking is implemented using a density integrated volume that reduces the integration steps performed.

Multiphase Hydrodynamics In Steady And Pulse Jet Mixing Systems, Ibraheem R. Muhammad

Dissertations

The goal of the present study is to evaluate the mixing performance of jet mixers in both liquid and solid-liquid mixing processes. Jet mixers have been studied for decades for its uses in liquid blending and solid-liquid mixing applications. In solid suspension processes, jet mixers can be just as useful if not more useful than conventional impeller mixers. However, there is a lack of phenomenological models that exist. The erosion and subsequent suspension of solids beds, as well as the suspension of a low concentration of solid particles must be better understood. The specific objectives were to develop analytical, experimental …

Predicting The Crack Response For A Pipe With A Complex Crack, Robert George Lukess

Theses and Dissertations

Traditional flaw evaluation in the nuclear field uses conservative methods to predict maximum load carrying capacity for flaws in a given pipe. There is a need in the nuclear industry for more accurate estimates of the load carrying capacity of nuclear piping such that probabilistic tools can be used to predict the time to failure for various types of cracks. These more accurate estimates will allow the nuclear industry to repair flaws at a more appropriate time considering external factors such as costs and man-rem planning along with the flaw repair. Analysis of the maximum load carrying capacity of a …

Evolution Of Microstructure Of Haynes 230 And Inconel 617 Under Mechanical Testing At High Temperatures, Kyle Hrutkay

Theses and Dissertations

Haynes 230 and Inconel 617 are austenitic nickel based superalloys, which are candidate structural materials for next generation high temperature nuclear reactors. High temperature deformation behavior of Haynes 230 and Inconel 617 have been investigated at the microstructural level in order to gain a better understanding of mechanical properties. Tensile tests were performed at strain rates ranging from 10-3-10-5 s-1 at room temperature, 600 °C, 800 °C and 950 °C. Subsequent microstructural analysis, including Scanning Electron Microscopy, Transmission Electron Microscopy, Energy-Dispersive X-ray Spectroscopy, and X-Ray Diffraction were used to relate the microstructural evolution at high temperatures to that of room …

The Study Of Alternate, Solid-Phase Fluorinating Agents For Use In Reactive Gas Recycle Of Used Nuclear Fuel, Dillon Inabinett

Theses and Dissertations

Surrogate oxides of the Used Nuclear Fuel (UNF) matrix were fluorinated using alternate, solid-phase fluorinating agents XeF2 and NH4HF2 to form volatile and non-volatile compounds and demonstrate the possibility of a chemical and thermal separations. A matrix of experiments was conducted at the milligram quantity scale using a Shimadzu DTG-60 TG/DTA installed at SRNL (Savannah River National Laboratory) for testing of all non-radioactive samples and a Netzsch STA 409 TGA installed in the laboratory at USC (University of South Carolina) for testing of all radioactive samples. The fluorination and subsequent volatilization potentials were analyzed by mixing excess fluorinating agent with …

Application Of Computational Fluid Dynamics Methods To Improve Thermal Hydraulic Code Analysis, Dennis Shannon Sentell, Jr.

Theses and Dissertations

A computational fluid dynamics code is used to model the primary natural circulation loop of a proposed small modular reactor for comparison to experimental data and best-estimate thermal-hydraulic code results. Recent advances in computational fluid dynamics code modeling capabilities make them attractive alternatives to the current conservative approach of coupled best-estimate thermal hydraulic codes and uncertainty evaluations. The results from a computational fluid dynamics analysis are benchmarked against the experimental test results of a 1:3 length, 1:254 volume, full pressure and full temperature scale small modular reactor during steady-state power operations and during a depressurization transient. A comparative evaluation of …

Advanced Fuels Modeling: Evaluating The Steady-State Performance Of Carbide Fuel In Helium-Cooled Reactors Using Frapcon 3.4, Luke H. Hallman

Theses and Dissertations

Uranium carbide (UC) has long been considered a potential alternative to uranium dioxide (UO2) fuel, especially in the context of Gen IV gas-cooled reactors. It has shown promise because of its high uranium density, good irradiation stability, and especially high thermal conductivity. Despite its many benefits, UC is known to swell at a rate twice that of UO2. However, the swelling phenomenon is not well understood, and we are limited to a weak empirical understanding of the swelling mechanism.

One suggested cladding for UC is silicon carbide (SiC), a ceramic that demonstrates a number of desirable properties. Among them are …

Characterization Of Two Ods Alloys: 18cr Ods And 9cr Ods, Julianne Kay Goddard

Theses and Dissertations

ODS alloys, or oxide dispersion strengthened alloys, are made from elemental or pre-alloyed metal powders mechanically alloyed with oxide powders in a high-energy attributor mill, and then consolidated by either hot isostatic pressing or hot extrusion causing the production of nanometer scale oxide and carbide particles within the alloy matrix; crystalline properties such as creep strength, ductility, corrosion resistance, tensile strength, swelling resistance, and resistance to embrittlement are all observed to be improved by the presence of nanoparticles in the matrix. The presented research uses various methods to observe and characterize the microstructural and microchemical properties of two experimental ODS …

Fabrication And Characterization Of Surrogate Fuel Particles Using The Spark Erosion Method, Kathryn Elizabeth Metzger

Theses and Dissertations

In light of the disaster at the Fukushima Daiichi Nuclear Plant, the Department of Energy's Advanced Fuels Program has shifted its interest from enhanced performance fuels to enhanced accident tolerance fuels. Dispersion fuels possess higher thermal conductivities than traditional light water reactor fuel and as a result, offer improved safety margins. The benefits of a dispersion fuel are due to the presence of the secondary non-fissile phase (matrix), which serves as a barrier to fission products and improves the overall thermal performance of the fuel. However, the presence of a matrix material reduces the fuel volume, which lowers the fissile …

Pellet Cladding Mechanical Interactions Of Ceramic Claddings Fuels Under Light Water Reactor Conditions, Bo-Shiuan Li

Theses and Dissertations

Ceramic materials such as silicon carbide (SiC) are promising candidate materials for nuclear fuel cladding and are of interest as part of a potential accident tolerant fuel design due to its high temperature strength, dimensional stability under irradiation, corrosion resistance, and lower neutron absorption cross-section. It also offers drastically lower hydrogen generation in loss of coolant accidents such as that experienced at Fukushima. With the implementation of SiC material properties to the fuel performance code, FRAPCON, performances of the SiC-clad fuel are compared with the conventional Zircaloy-clad fuel. Due to negligible creep and high stiffness, SiC-clad fuel allows gap closure …

A New Approach To Nuclear Safeguard Enhancement Through Radionuclide Profiling, Aaron Dawon Peterson

Masters Theses

"The United States has led the effort to promote peaceful use of nuclear power amongst states actively utilizing it as well as those looking to deploy the technology in the near future. With the attraction being demonstrated by various countries towards nuclear power comes the concern that a nation may have military aspirations for the use of nuclear energy. The International Atomic Energy Agency (IAEA) has established nuclear safeguard protocols and procedures to mitigate nuclear proliferation. The work herein proposed a strategy to further enhance existing safeguard protocols by considering safeguard in nuclear fuel design. The strategy involved the use …

Insufficient Ct Data Reconstruction Based On Directional Total Variation (Dtv) Regularized Maximum Likelihood Expectation Maximization (Mlem) Method, Fahima Fahmida Islam

Masters Theses

"Sparse tomography is an efficient technique which saves time as well as minimizes cost. However, due to few angular data it implies the image reconstruction problem as ill-posed. In the ill posed problem, even with exact data constraints, the inversion cannot be uniquely performed. Therefore, selection of suitable method to optimize the reconstruction problems plays an important role in sparse data CT. Use of regularization function is a well-known method to control the artifacts in limited angle data acquisition. In this work, we propose directional total variation regularized ordered subset (OS) type image reconstruction method for neutron limited data CT. …

Design, Development And Characterization Of A Novel Neutron And X-Ray Combined Computed Tomography System, Vaibhav Sinha

Doctoral Dissertations

"Visualizing the three dimensional structure of objects (e.g. nuclear fuel, nuclear materials, explosives and bio materials) and phenomena (e.g. particle tracking) can be very important in nondestructive testing applications. Computed tomography systems are indispensable tools for these types of applications because they provide a versatile non-destructive technique for analysis. A novel neutron and X-ray combined computed tomography (NXCT) system has been designed and developed at the Missouri University of Science & Technology. The neutron and X-ray combined computed tomography system holds much promise for non-destructive material detection and analysis where multiple materials having similar atomic number and differing thermal cross …

Cfd Simulation Of Void Flow In Eccs, Lifeng Wang

Masters Theses

"Emergency core cooling system (ECCS) has been studied extensively for reactor safety. Emergency core cooling system (ECCS) is designed to make sure the reactor core it is protected by providing sufficient heat removal during accident conditions. In a loss-of-coolant-accident (LOCA) scenario, the ECCS is designed to take over the reactor core cooling by drawing water from a reservoir or tank. Voids may be introduced into the ECCS through a variety of means leading to total or partial loss of suction supply, or through gas depressurization resulting from difference in gas saturation pressure and ambient pressure. The transportation of voids through …

Method And Apparatus For Adaptive Scatter Correction, Xin Liu, J. Hsieh, X. Wu

Nuclear Engineering and Radiation Science Faculty Research & Creative Works

A CT system includes a rotatable gantry having an opening to receive an object to be scanned, an x-ray source configured to project an x-ray beam toward the object having a primary intensity, a detector configured to detect high frequency electromagnetic energy passing through the object and output imaging data, and a data acquisition system (DAS) connected to the detector and configured to receive the imaging data. The system also includes a computer programmed to obtain image projection data of the object from the DAS, correct the projection data using a scatter function that is based at least on a …

The Effect Of Gamma Radiation On Fibre Bragg Grating Sensors When Used As Radiation Dosimeters, Des Baccini

Theses : Honours

The effects of Gamma Radiation on Fibre Bragg Gratings (FBGs), when used as a radiation dosimeter, was proposed. The focus of this study centred on the FBG performance, and in particular the Bragg Wavelength Shift (BWS) whilst being exposed to ionizing radiation. Current research suggests that certain types of fibres manufactured by varying methods produce different results. The different responses to exposure from gamma irradiation between Germanium (Ge) doped optical fibres, with and without Hydrogen loading, along with the standard SMF-28 fibre with Hydrogen, were used and results noted and compared to previous work. The FBG’s in each fibre were …

Novel Production Techniques Of Radioisotopes Using Electron Accelerators, Daniel Robert Lowe

UNLV Theses, Dissertations, Professional Papers, and Capstones

Non-traditional radioisotope production techniques using a compact, high power linear electron accelerator have been demonstrated and characterized for the production of 18F, 47Sc, 147Pm, and 99mTc from a variety of target candidates. These isotopes are used extensively in the medical field as diagnostic and therapy radioisotopes, as well as the space industry as RTG's. Primary focus was placed on 99mTc as it constitutes approximately 80% of all diagnostic procedures in the medical community that use radioactive tracers. It was also the prime focus due to recent events at the Chalk River nuclear reactor, which caused global shortages of this isotope …

The Challenges And Implications For Energy Education, Patrick A. Tebbe

Mechanical and Civil Engineering Department Publications

In March 2011, the Fukushima Daiichi Nuclear Power Station in Japan was hit by twin natural disasters of a 9.0 earthquake and a tsunami more than 10 meters high. The combination forced a shut down of the reactor and severed externally provided power. Backup generators and batteries, which at first functioned normally, were swamped and disabled by the tsunami waters. The subsequent loss of reactor core cooling led to rising temperatures that ultimately resulted in a partial melting of the fuel rods and several hydrogen explosions (produced by a steam-zirconium reaction). Eventually, the situation was brought under control, but not …

The Leading Contributor Of The Fukushima Daiichi Nuclear Power Plant Accident, Christopher Torres

Liberal Arts and Engineering Studies

No abstract provided.

Cellular Automaton For Simulation Of Oxide Layer Growth Influenced By Chromium Concentration Of Structure Material, Kuan-Che Lan, Yitung Chen, Ge-Ping Yu, Tzu-Chen Hung

College of Engineering: Graduate Celebration Programs

Chromium, an important alloying element, has been added in ferrous and nickel based alloy such as stainless steels and Inconel alloy to improve the corrosion resistance. High corrosion resistance of structural materials in extremely high working temperature is one crucial R&D objective of Gen IV nuclear power plants which propose to raise the thermal efficiency via high working temperature. A cellular automaton (CA) model based on the stochastic approach was proposed to simulate the process of oxidation and corrosion of structural material in flowing fluid. The relation of chromium concentration against oxide layer thickness during a specific period was found. …

Theoretical Study Of The Effects Of Di-Muonic Molecules On Muon-Catalyzed Fusion, Eugene V. Sheely

Theses and Dissertations

This document presents a theoretical study di-muonic hydrogen and helium molecules that have the potential of enhancing the muon-catalyzed fusion reaction rate. In order to study these di-muonic molecules a method of non-adiabatic quantum mechanics referred to as a General Particle Orbital (GPO) method was developed. Three mechanisms that have the possibility of enhancing the muon-catalyzed fusion rate were discovered. Two involve the formation of di-muonic hydrogen molecules, and the other uses di-muonic molecules to liberate muons stuck to ³He nuclei. The effects of muon spin on dimuonic hydrogen molecules was studied. The nuclear separation in di-muonic hydrogen molecules …

A Programmable Liquid Collimator For Both Coded Aperture Adaptive Imaging And Multiplexed Compton Scatter Tomography, Jack G. M. Fitzgerald

Theses and Dissertations

A novel, fully reconfigurable collimator device for gamma-ray and X-ray imaging was built and tested as a coded aperture. The device consisted of 10x10, 5x5x5 mm³ chambers. Each chamber either was filled with an attenuating liquid, stopping photons, or evacuated of the attenuating liquid, allowing the photons to pass through. As the pattern of on and off chambers was manipulated, different, semi-independent views of the gamma-ray source were found. Noise in reconstructed images decreased in all tests. Image reconstruction was performed with correlation methods and Maximum Likelihood Expectation Maximization (ML-EM). Using 10 mask patterns, the signal-to-noise ratio (SNR) in …

Managing The Future Energy Policy For Ireland: Examining The Role Of Nuclear Power, Declan Lynch, Angela Wright

Dept. of Organisation & Professional Development Publications

This study assesses the attitudes and opinions of Irish people towards the use of nuclear power, and specifically examines the concept that Ireland should use nuclear power to generate electricity in the future. Currently, Ireland has a prohibition on nuclear power, with little debate or discussion on same, and with scant amounts of information published on the subject as it relates to Ireland. Conversely, from an international perspective, there is a significant volume of literature available covering all aspects of nuclear power, generated from over 50 years of nuclear power operations. Nuclear power technology is perceived as being a relatively …

Evolutionary Optimization Of Electronic Circuitry Cooling Using Nanofluid, Manu Mital

Mechanical and Nuclear Engineering Publications

Liquid cooling electronics using microchannels integrated in the chips is an attractive alternative to bulky aluminum heat sinks. Cooling can be further enhanced using nanofluids. The goals of this study are to evaluate heat transfer in a nanofluid heat sink with developing laminar flow forced convection, taking into account the pumping power penalty. The proposed model uses semi-empirical correlations to calculate effective nanofluid thermophysical properties, which are then incorporated into heat transfer and friction factor correlations in literature for single-phase flows. The model predicts the thermal resistance and pumping power as a function of four design variables that include the …

Optimizing Fiber Cross-Sectional Shape For Improving Stability Of Air–Water Interface Over Superhydrophobic Fibrous Coatings, B. Emami, Hooman Vahedi Tafreshi

Mechanical and Nuclear Engineering Publications

In this letter, a mathematical force-balance formulation is developed that can be used to predict the critical pressure, the hydrostaticpressure above which the surface starts to depart from the non-wetting state, for superhydrophobicsurfaces comprised of highly aligned fibers (e.g., biased AC-electrospun coatings) with arbitrary cross-sectional shapes. We have also developed a methodology for optimizing the fiber cross-sections to maximize the critical pressure of the surface, using the Euler–Lagrange equation. A case study is presented to better demonstrate the application of our method.

Effect Of Fiber Orientation On Shape And Stability Of Air-Water Interface On Submerged Superhydrophobic Electrospun Thin Coatings, B. Emami, H. Vahedi Tafreshi, M. Gad-El-Hak, G. C. Tepper

Mechanical and Nuclear Engineering Publications

To better understand the role of fiber orientation on the stability of superhydrophobicelectrospun coatings under hydrostaticpressures, an integro-differential equation is developed from the balance of forces across the air–water interface between the fibers. This equation is solved numerically for a series of superhydrophobicelectrospun coatings comprised of random and orthogonal fiber orientations to obtain the exact 3D shape of the air–water interface as a function of hydrostaticpressure. More important, this information is used to predict the pressure at which the coatings start to transition from the Cassie state to the Wenzel state, i.e., the so-called critical transition pressure. Our results indicate …