Nuclear Engineering Commons^™

Computer Aided Detection Of Oral Lesions On Ct Images, Shaikat Mahmood Galib

Masters Theses

"Oral lesions are important findings on computed tomography images. They are difficult to detect on CT images because of low contrast, arbitrary orientation of objects, complicated topology and lack of clear lines indicating lesions. In this thesis, a fully automatic method to detect oral lesions from dental CT images is proposed to identify (1) Closed boundary lesions and (2) Bone deformation lesions. Two algorithms were developed to recognize these two types of lesions, which cover most of the lesion types that can be found on CT images. The results were validated using a dataset of 52 patients. Using non training …

Initial Fuel Possibilities For The Thorium Molten Salt Reactor, Dustin Gage Green

Masters Theses

"The Generation IV International Forum placed six reactors as priority for research and development to compensate for the world's increasing energy demands. Among the six were Molten Salt Reactors (MSRs). These reactors utilize the Th/²³³U fuel cycle using molten fluoride or chloride salts as coolants. MSRs also have the possibility to use other fissile fuels especially with the first fleet of reactors given the low amount of Uranium-233 available commercially.

With the possibility of diverting from using ²³³U initially, the research presented here will benchmark ²³³U as a main fuel for MSRs using the Thorium Molten …

Determination Of Minor And Trace Elements Concentration In Kidney Stones Using Elemental Analysis Techniques, Anjali Srivastava

Masters Theses

"The determination of accurate material composition of a kidney stone is crucial for understanding the formation of the kidney stone as well as for preventive therapeutic strategies. Radiations probing instrumental activation analysis techniques are excellent tools for identification of involved materials present in the kidney stone. The X-ray fluorescence (XRF) and neutron activation analysis (NAA) experiments were performed and different kidney stones were analyzed. The interactions of X-ray photons and neutrons with matter are complementary in nature, resulting in distinctly different materials detection. This is the first approach to utilize combined X-ray fluorescence and neutron activation analysis for a comprehensive …

Feasibility Study Of A Two-Fluid Small Modular Molten Salt Reactor With In Core Heat Removal Capability, Brandon James Lahmann

Masters Theses

"A feasibility study of a two-fluid small modular molten salt reactor (MSR) with in core heat removal was performed. The initial fuel block dimension for the configuration was based on the Fuji MSR. The fuel was a mixed fluoride salt of density 3.25 g/cc, composed of 71 LiF - 16 BeF₂ - 12 ThF₄- 1 ²³³UF₄ molar percentages. The coolant salt was Li₄(FLiBe) of density 1.94 g/cc. The work set out to establish whether or not such a reactor is thermodynamically feasible when optimized for various neutronics parameters. A Java based API was …

Experimental Investigation Of The Pebble Bed Structure By Using Gamma Ray Tomography, Fadha Shakir Ahmed

Masters Theses

"Pebble Bed Reactors offer a future for new nuclear energy plants. They are small, inherently safe, and can be competitive with fossil fuels. The fuel forms a randomly stacked pebble with non-uniform fuel densities. The thermal-mechanical behavior of pebble bed reactor core is depends strongly on the spatial variation of packing fraction in the bed and in particular on the number of contacts between pebbles, and between the pebbles and the blanket walls. To investigate these effects, experimental data to characterize bed structure are needed along with other numerical simulation and computational tools for validation.

In this study, a powerful …

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. …

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 …

Hot Channel Determination And Burnup Analysis Of Missouri University Of Science And Technology Research Nuclear Reactor, Kelly Christopher Rogers O'Bryant

Masters Theses

"A burnup analysis has been performed on the Missouri University of Science and Technology (Missouri S&T) Research Nuclear Reactor (MSTR). With use of the Monte Carlo neutronics depletion code MCNPX, burned material was input into a neutronics model (burned model) in order better simulate MSTR core characteristics. Simulated burnup values of ²³⁵U for the past twenty years of MSTR operations totaled 14.266 grams, slightly less than the 14.527 grams reported by the reactor staff. A distribution of ²³⁵U was simulated and a burnup map was developed.

Using the updated fuel material, the hot channel of the current configuration of the …

Verification Of A Monte Carlo Model Of The Missouri S&T Reactor, Brad Paul Richardson

Masters Theses

The purpose of this research is to ensure that an MCNP model of the Missouri S&T reactor produces accurate results so that it may be used to predict the effects of some desired upgrades to the reactor. The desired upgrades are an increase in licensed power from 200 kW to 400kW, and the installation of a secondary cooling system to prevent heating of the pool. This was performed by comparing simulations performed using the model with experiments performed using the reactor. The experiments performed were, the approach to criticality method of predicting the critical control rod height, measurement of the …

Wavelet Based Contrast Limited Histogram Equalization For Contrast Enhancement Of Digital Mammography, Ashish Vighnahar Avachat

Masters Theses

"Mammography has been the most efficient tool for screening of microcalcification and cancer tissues; however, the raw images produced by mammography systems are usually of poor contrast. In order to use these raw images for early diagnosis; their contrast, sharpness and noise need to be enhanced. Among these important enhancement parameters contrast enhancement is critical. A novel algorithm is introduced which blends wavelet transforms with Contrast Limited Adaptive Histogram Equalization (CLAHE) for contrast enhancement. In this algorithm, the input image is decomposed to its low frequency and high frequency components in wavelet domain. Decomposed coefficients from different bands are then …

Determination Of Linear Attenuation Coefficients Of Chemically Bonded Phosphate Ceramics, Jason Joseph Pleitt

Masters Theses

"Chemically Bonded Phosphate Ceramics (CBPCs) is a composite based material formed in a manner similar to cements. CBPCs have shown to be a good structural material with excellent thermal resistance properties. They have also been shown to have potential as a radiation shield. By incorporating various powders into the ceramic the improvement in its radiation shielding properties are examined. The method for obtaining the linear attenuation coefficients for CBPCs as well as MCNP simulated results for gamma and neutrons are presented"--Abstract, page iv.

Production And Characterization Of Supported Palladium Nanoparticles On Multiwalled Carbon Nanotubes By Gamma Irradiation, Jessika Viviana Rojas Marin

Masters Theses

"Carbon nanotubes are being studied for a variety of applications due to their outstanding mechanical, chemical, electrical, and optical properties that make them interesting in different areas. Nowadays, different methods to modify the structure of the nanotubes are being developed in order to expand the application fields of such materials. In this work, palladium nanoparticles were directly produced and supported on multi-walled carbon nanotubes (MWCNT) by gamma irradiation. A solution with a 2:1 water-isopropanol ratio was prepared and mixed with palladium chloride as precursor of palladium ions. Radiolysis of water produces certain species that reduce the ions down to a …

Simulation Of The Field Electron Emission Characteristics Of A Flat Panel X-Ray Source, Chrystian Mauricio Posada ArbeláEz

Masters Theses

"A distributed flat panel x-ray source is designed as an alternative for medical and industrial imaging fields. The distributed x-ray source corresponds to a two dimensional array of micro (~100μm) x-ray cells similar in format to a field emission display. In this paper the electron field emission characteristics of a single of the proposed micro-sized x-ray cells are simulated. The field electron emission from the CNTs-based cathode is simulated using the Particle-In-Cell code OOPIC Pro. The electron source is simulated as a triode structure, composed of an emitting cathode, extracting grid and anode. The possibility of using focusing lenses to …

Density Determination Of Tristructural-Isotropic Nuclear Fuel Using Multiple Projection X-Ray Radiography, Frank Angelo Strantz

Masters Theses

"Effective methods of enhancing the safety and efficiency of the nuclear power industry embolden its perception and economic viability. Fuel reliability is an essential component of the prosperity of next generation high temperature reactors; as such, an equally dependable quality control method is mandatory. Tristructural-isotropic (TRISO) fuel, the fuel developed for use in these reactors, utilizes density measurement of coating layers as a standard for quality control. Common methods of measuring density, such as sink-float and ceramography are destructive, and as such generate radioactive waste, take a relatively long time to prepare samples, rely on a low sampling rate to …

Upgrade And Simulation Of The Subcritical Assembly At Missouri University Of Science And Technology, Lucas Powelson Tucker

Masters Theses

"The Missouri University of Science and Technology Subcritical Assembly (S&TSub) was brought back into service and upgraded with a new neutron detection system and internet access. Before the upgrade neutron counting was only possible in one location. Using a movable detection system housed in acrylic tubes measurements can now be taken in any empty fuel location and at any height within the tube, making three dimensional flux mapping a possibility. By connecting the new detection system to a Canberra Lynx Digital Signal Analyzer, remote users can have limited data collecting capabilities. To further enhance the potential of the facility, an …

Contrast Enhancement Of Digital Mammography Based On Multi-Scale Analysis, Muhammad Imran Khan Abir

Masters Theses

"A contrast enhancement algorithm is developed for digital mammograms aiming to assist radiologists in discerning early breast cancer easily. The algorithm is based on a Laplacian pyramid framework image processing technique. The mammogram is decomposed into three frequency sub-bands, low, mid, and high frequency sub-band images. The lower sub-band image contains very fine details and higher level contains coarser features. In this method contrast enhancement is achieved from high and mid sub-bands by decomposing the image based on multi-scale Laplacian pyramid and enhance contrast by image processing. Several mapping functions are applied on sub-band images based on experimental analysis. After …

Characterization Of The Neutron Flux Spectrum At The Missouri University Of Science And Technology Research Reactor, Zachary Andrew Kulage

Masters Theses

"A new remotely accessible shielded cell is being constructed at the Missouri University of Science and Technology Research Reactor (MSTR). The heavily shielded cell will be able to receive highly irradiated specimens directly from the reactor and will be equipped with radiation-hardened cameras, remote manipulators and gamma spectroscopy. The cell will allow the manipulation and monitoring of highly activated specimens from both a workstation at the MSTR and at remote locations using a Webbased internet interface. The ability to access and control the shielded cell via a remote internet connection will make it useful to a wide variety of users. …

Internet-Accessible Hot Cell With Gamma Spectroscopy At The Missouri University Of Science And Technology Research Nuclear Reactor, Edwin Grant

Masters Theses

A dual-chambered internet-accessible heavily shielded facility with pneumatic access to the University of Missouri Science and Technology (Missouri S&T) 200 kW Research Nuclear Reactor (MSTR) core has been built and is currently under low level irradiation testing. The facility allows distance users doing collaborative work with Missouri S&T researchers to manipulate and analyze neutron irradiated samples remotely. The system consists of two shielded compartments, one for multiple sample storage (up to 11 samples), and the other for isolated radiation measurements and spectroscopy. The second chamber has multiple detector ports, graded shielding, and has the capability to support gamma spectroscopy using …

Analogy Based Modeling Of Natural Convection, Vaibhav Khane

Masters Theses

"This research is an extension of previous work on the development of an integrator or resistance-capacitance circuit analogy for natural convection. As a part of a larger project to enhance transport phenomenon on a micro-scale using radiation, this work studied the phenomenon of natural convection. Using experimental techniques and numerical simulations (FLUENT code), it investigated the transient response of a natural convection system. It proposes an integrator circuit analogy for a natural convection system. Experimental investigation with three different fluids indicated that the characteristic time constant of the system is related to the Prandtl number of the fluid. The project …

Equivalent Circuit For Transient Conduction And Convection Systems, Bassam Sabry Mohammad Abdelnabi

Masters Theses

"Transient response of a natural convection system is investigated by numerical simulation using FLUENT code. An Integrator Circuit analogy was recently proposed for natural convection system. The proposed analogy was further confirmed by these recent simulations. New simulation results also suggest that a natural convection system acts as a "Low Pass" filter for transients. Transient transmission/attenuation factor was found to be a function of both fluid properties and the flow characteristics. Transmission/attenuation factor was also found to be a strong function of fluctuation frequency"--Abstract, page iv.

Effects Of Specimen Size Reduction On The Transition Curve Of The Charpy V-Notch Impact Test, Lonnie Eugene Schubert

Masters Theses

"This study was undertaken to correlate the impact properties of ASTM standard full size Charpy V-notch impact specimens to the impact properties of subsize specimens. An ASTM A533-B quenched and tempered plate steel was examined. The fine grained martensitic material had a coarse prior austenite grain size, which resulted in a low upper shelf energy for this material. Three sizes of specimens were included. Specimens were irradiated in the TRIGA Reactor Facility operated by the U. S. Geological Survey in Denver, Colorado, to 1 x 10¹⁹ n/cm² (E > 1 MeV) at 150°C (302°F). Unirradiated and irradiated specimens were …

Dose Rate Determination Of The Highly-Enriched Uranium Fuel At The University Of Missouri-Rolla Reactor In Preparation For Transportation, Alice Ann Netzer

Masters Theses

"An analytical model was developed in order to accurately estimate the dose rates in air of the highly-enriched uranium (HEU) fuel at the University of Missouri - Rolla Reactor. Based upon these results, a method is proposed to remove the fuel from the reactor.

First thermoluminescent dosimeters (TLDs) were exposed under water to each of the fuel elements in the reactor pool, except for the four control rodded elements. A model was developed to use the in-water TLD readings to calculate the dose rate of the fuel elements in air at 1 foot and 3 feet. The fuel was modeled …

Mechanical And Neutronic Properties Of Neutron Absorbing Materials, Donald James Buth

Masters Theses

“The primary neutron absorbing material examined in this project was Boraflex™, which consists of a silicone polymer with boron carbide acting as the neutron absorber. Two aluminum based neutron absorbers, Boral™ and Al-B-Ten, were also examined. Both X-ray and neutron radiography were used to examine the Boraflex™. The neutron radiography gave better resolution in detecting fluctuations in the boron carbide distribution; however, X-ray radiography did perform better in detecting flaws in the base material. Tensile tests were performed to determine the uniformity of Boraflex™'s tensile properties. The average tensile strength was calculated to be 303 ± 15 psi. A small …

Dimensional Change Correlations For 20% Cold Worked Aisi 316 Stainless Steel For Fusion Applications, Robert Wayne Clark

Masters Theses

"Dimensional instability of structural components in a fusion reactor Is expected to occur during Its operation. This expectation is based upon experience with fast reactors In the United States, France and United Kingdom. Correlations for void swelling and Irradiation creep are developed in this thesis for 20% cold worked AISI 316 Stainless Steel for fusion applications.

The sensitivities of swelling to variations in composition, fabrication and the Irradiation environment I le al roost exclusively in the duration of the transient regime of swelling. Irradiation creep rates at high exposures are also expected to exhibit a similar parametric insensitivity, largely because …

Fuel Loading For A Low-Leakage Core In A Pressurized Water Reactor, Omar Ivan Aguilar

Masters Theses

"A study of low-leakage core fuel loading as a means to reduce fast neutron flux incident upon the pressure vessel is presented. The specific case under study is Cycle 5 of Arkansas Nuclear One - Unit Two (ANO-2), a Combustion Engineering Pressurized Water Reactor. Neutron transport calculations were performed using the DOT two-dimensional transport code. The results from DOT provide the angular distribution of the fast neutron flux at the surface of the pressure vessel.

Seven different fuel loading schemes were studied and compared to the Reference Case. The angular distribution of the fast neutron flux for all cases studied …

Evaluation Of A Near-Surface Low-Level Radioactive Waste Disposal Facility For The State Of Missouri, Christine Lang Nelson

Masters Theses

"A low-level radioactive waste disposal facility for the state of Missouri Is designed. The proposed facility Is to be placed in a mined opening within a Precambrian granite outcrop in southeastern Missouri.

A safety assessment of the proposed facility was performed. The method used was fault tree analysis.

The threat of seismic activity within the region ls seen to be the main determent to the proposed design. Groundwater modelling was not possible due to a lack of data.

The facility design Includes a provision for the retrieval of the low-level waste once the waste has decayed to acceptable levels"-- Abstract, …

The Compositional And Temperature Dependence Of Radiation-Induced Void Nucleation And Swelling In Austenitic Alloys, Bahram Esmailzadeh

Masters Theses

"The objective of this study is to introduce a model which can demonstrate the major features of the compositional and temperature dependence of radiation-induced swelling of austenitic alloys. The effective vacancy diffusion coefficient, D_V^eff, is the prime variable explored in this study. Variations in D_V^eff with composition and/or irradiation temperature are used along with the KWR nucleation theory to determine the subsequent effects of these variables on the void nucleation rate and the duration of the transient regime. The materials chosen for this study are nickel (Ni) and the Ni-Si, Fe-Ni-Cr and Fe-Ni-Cr-Si alloy systems. …

A Theoretical And Experimental Investigation Of Single Phase Flow Through A Small Centrifugal Pump In Three Quadrants Of Operation, Lee Charles Cadwallader

Masters Theses

"The operating characteristics of a conventional centrifugal pump have been investigated, both theoretically and experimentally, in three modes of operation with single phase liquid water at atmospheric pressure and room temperature.

Simple one-dimensional theory has been used to evaluate the theoretical pump performance, and these evaluations are compared to actual experimental data. The actual data shows the degradation effects of flow friction and shock losses that the theory does not take into account. The comparison of the curves illustrates these differences.

The data obtained compares well to and reinforces data from experiments found in the literature review.

Based on the …

Analyzing And Predicting Natural Circulation In A Snupps's Pwr Using "Retran-01", Roger Lee Boyer

Masters Theses

"The purpose of this project is to predict the natural circulation start-up test for the Standardized Nuclear Unit Power Plant System (SNUPPS). In order to make this prediction, a best-estimate, thermal-hydraulic computer code called RETRAN-01 is used.

The start-up test procedures require the simultaneous tripping of all four reactor coolant pumps (RCPs). Natural circulation is confirmed when the three test acceptance criteria have been met. Since this transient is symmetrical, a one-loop approximation of the Nuclear Steam Supply System (NSSS) is normally considered adequate in the nuclear industry. However, there is a concern over how to model the four actual …