Nuclear Engineering Commons^™

Development Of Complex Lattice Cell In Benchmark Model Of Particle Bed Critical System, Elijah Chamberlain Lutz

Masters Theses

“Criticality safety benchmark evaluations require the creation of models that most accurately represent the experiment being evaluated. In some cases this can be relatively trivial with experiments containing rather simple or standard geometry. In others, such as packed bed systems, this becomes unique and a more difficult process. The importance of accurate modeling of packed bed systems for the use of criticality safety benchmark evaluations was looked at. Four models were created of various complexities and accuracy. First the multi-particle bed, consisting of a fuel particle (UC_1.7 kernel with C shell) and two filler particles (Zircaloy-4 and C + …

Effect Of Radiation Damage On Organic Phase Change Materials Thermal Storage Properties, Ryan Phillip Steere

Doctoral Dissertations

"This work discusses the effects of radiation damage on organic phase change materials for use in nuclear reactor containments and space craft. The effects of radiation on the latent heat of polyethylene wax (PEW) and a eutectic of methyl palmitate and lauric acid (EMPaLA) are evaluated. These PCMs were irradiated in three locations: the Missouri University of Science and Technology research reactor (MSTR), the University of Missouri research reactor (MURR) and cyclotron (MUC) up to a total dose of 2826, 2895 and 662 Gy, respectively. The samples irradiated at the MSTR showed latent heat changes up to 15.5% lower than …

Scaling, Experiments, And Simulations Of Condensation Heat Transfer For Advanced Nuclear Reactors Safety, Palash Kumar Bhowmik

Doctoral Dissertations

“The purpose of this research was to perform scaled experiments and simulations to validate computational fluid dynamics (CFD) and empirical models of condensation heat transfer (CHT) for the passive containment cooling system (PCCS) of Small Modular Reactors (SMRs). SMRs are the futuristic candidates for clean, economic, and safe energy generation; however, reactor licensing requires safety system evaluations, such as PCCS. The knowledge in the reviewed relevant literature showed a gap in experimental data for scaling SMR’s safety systems and validating computational models. The previously available test data were inconsistent due to unscaled geometric and varying physics conditions. These inconsistencies lead …

Experimental Evaluation Of The Deadtime Phenomenon For Gm Detector: Deadtime Dependence On Operating Voltages, Bader Almutairi, Syed B. Alam, Tayfun Akyurek, Cameron S. Goodwin, Shoaib Usman

Nuclear Engineering and Radiation Science Faculty Research & Creative Works

A detailed analysis of Geiger Mueller counter deadtime dependence on operating voltage is presented in the manuscript using four pairs of radiation sources. Based on two-source method, detector deadtime is calculated for a wide range of operating voltages which revealed a peculiar relationship between the operating voltage and the detector deadtime. In the low voltage range, a distinct drop in deadtime was observed where deadtime reached a value as low as a few microseconds (22 µs for ²⁰⁴Tl, 26 µs for ¹³⁷Cs, 9 µs for ²²Na). This sharp drop in the deadtime is possibly due to reduced …

Corrigendum: “A Correlation For Interfacial Area Concentration In High Void Fraction Flows In Large Diameter Channels” ([Chem. Eng. Sci.131 (2015) 172–186] (2015) 131 (172–186), (S0009250915002547), (10.1016/J.Ces.2015.04.004)), Joshua P. Schlegel, T. Hibiki

Nuclear Engineering and Radiation Science Faculty Research & Creative Works

There is a Typographical Mistake in Eq. (21), Used in the Derivation of the Final Model, Which Should Read [Fourmula Presented] This Typographical Mistake is Also Present in Eq. (22b), Which is Necessary for Implementation of the Final Model, Which Should Read

Modification Of The Optical Response Of Alpha Quartz Via The Deposition Of Gold Nanoparticles In Etched Ion Tracks, Maria C. Garcia Toro

Doctoral Dissertations

”This study addresses the experimental methods used to develop and characterize plasmonic devices capable of modifying the optical response of alpha quartz via the deposition of gold nanoparticles in etched ion tracks. In the first part of the research, the microstructural characterization of latent and etched ion tracks produced in alpha quartz (α-SiO₂) is presented. Single crystals of α-SiO₂ were irradiated with two highly energetic ions to different nominal fluences. As expected, the morphology of the resulting ion tracks depends on the energy of the incident ion and their stopping powers within the target material. Subsequent chemical …

Design Of X-Ray Source For Real-Time Computed Tomography, Wesley William Tucker

Doctoral Dissertations

"The reduction of motion blur in computed tomography (CT) drives the current research for multisource CT. Due to their compact nature, the current multisource systems utilize stationary angled anodes. Unfortunately, these configurations neither simplify the imaging geometry, nor satisfy the need for managing the high thermal loads demanded by real-time CT (30 acquisition frames per second). To add to the current field of knowledge, two x-ray tube concepts are presented in this dissertation. First, a simulation of transient thermal analysis was performed on a compact transmission-type x-ray tube anode operating in pulse-mode. A correlation was found between deposited beam power …

Characterization Of Neutron Irradiated Accident Tolerant Nuclear Fuel Cladding Silicon Carbide & Radiation Detector Deadtime, Bader Almutairi

Doctoral Dissertations

“In part I, the pulse shape characteristics generated by a Geiger Muller (GM) detector and recorded by an oscilloscope manually, were investigated. The objective of part I was (1) to find a correlation between pulse shape and the operating voltage; and (2) to assess if pulse shape properties followed distinct patterns comparable to detector deadtime findings reported by a previous study. It was observed that (1) there is a strong correlation between pulse shape and operating voltage, and (2) pulse shape falls in three distinct regions similar to detector deadtime. Furthermore, parts II and III are companions and share the …

Modeling A Nuclear Research Reactor And Radiation Dose Estimation In An Accident Scenario, Abdulaleem Abdulmajeed Bugis

Doctoral Dissertations

“A detailed, flexible three-dimensional (3D) model of the Missouri S&T Reactor (MSTR) with a heterogeneous core geometry was developed using the Standardized Computer Analyses for Licensing Evaluation (SCALE). A Graphical User Interface (GUI) was developed for SCALE, which allows the user to generate an input file automatically. The SCALE model was validated with a Monte Carlo N-Particle Transport (MCNP) model of the MSTR. The validation process was based on the criticality calculations using the Criticality Safety Analysis Sequence (CSAS6). Three geometrical models were examined. The SCALE model that has the full detailed geometry showed a good agreement with the MCNP …

Development Of Radiation Transport Techniques For Modelling A High-Resolution Multi-Energy Photon Emission Tomography System, Seth Kilby

Doctoral Dissertations

”Nondestructive characterization techniques such as gamma tomography represent powerful tools for the analysis and quantification of physical defects and radionuclide concentrations within nuclear fuel forms. Gamma emission tomography, in particular, has the ability to utilize the inherent radiation within spent nuclear fuel to provide users with information about the migration and concentration of fission and activation products within the fuel form. Idaho National Laboratory is interested in using this technology to analyze new nuclear fuel forms for potential use in next generation nuclear reactors. In this work, two aspect of the system are analyzed. The first is a semi-analytic radiation …

Analysis Of Energy Economy In Muon Catalyzed Fusion Considering External X-Ray Reactivation, Nishant Raghav Pillai

Masters Theses

"An analysis of the energy economy of a theoretical muon-catalyzed nuclear fusion system has been made by invoking the use of point kinetic equations, Monte Carlo radiation transport simulations, and from a review of existing literature on muon-catalyzed fusion. An external X-ray reactivation source is proposed as a novel way to increase the number of fusions per muon and thereby overcome the so-called alpha sticking problem that has long been considered the primary impediment to breakeven muon-catalyzed fusion power. Free electron lasers, synchrotrons and Wakefield accelerators are discussed as possible bright X-ray photon sources. The addition of an intense external …

Neutronic Investigation Of Alternative & Composite Burnable Poisons For The Soluble-Boron-Free And Long Life Civil Marine Small Modular Reactor Cores, Syed B. Alam, Bader Almutairi, Tuhfatur Ridwan, Dinesh Kumar, Cameron S. Goodwin, For Full List Of Authors, See Publisher's Website.

Nuclear Engineering and Radiation Science Faculty Research & Creative Works

Concerns about the effects of global warming provide a strong case to consider how best nuclear power could be applied to marine propulsion. Currently, there are persistent efforts worldwide to combat global warming, and that also includes the commercial freight shipping sector. In an effort to decarbonize the marine sector, there are growing interests in replacing the contemporary, traditional propulsion systems with nuclear propulsion systems. The latter system allows freight ships to have longer intervals before refueling; subsequently, lower fuel costs, and minimal carbon emissions. Nonetheless, nuclear propulsion systems have remained largely confined to military vessels. It is highly desirable …

Methods Of Use And Manufacture Of Silver-Doped, Nano-Porous Hydroxyapatite, Cheol-Woon Kim, Richard K. Brow

Nuclear Engineering and Radiation Science Faculty Research & Creative Works

A silver-doped, nano-porous hydroxyapatite material is provided that can be utilized to capture radioactive iodine, ¹²⁹I. Methods of using the silver-doped, nano-porous hydroxyapatite material to remove radioactive iodine, and methods of manufacturing the material are also provided.

The Blue Emission At 2.8 Ev In Strontium Titanate: Evidence For A Radiative Transition Of Self-Trapped Excitons From Unbound States, Miguel L. Crespillo, Joseph T. Graham, Fernando Agullo-Lopez, Y. Zhang, William J. Weber

Nuclear Engineering and Radiation Science Faculty Research & Creative Works

The origin of the blue emission in SrTiO₃ has been investigated as a function of irradiation fluence, electronic excitation density, and temperature using a range of ion energies and masses. The emission clearly does not show correlation with the concentration of vacancies generated by irradiation but is greatly enhanced under heavy-ion irradiation. The intensity ratio of the 2.8 and 2.5 eV bands is independent of fluence at all temperatures, but it increases with excitation rate. The 2.8 eV emission is proposed to correspond to a transition from conduction band states to the ground state level of the self-trapped exciton …

Achieving High-Power Configuration In Missouri S&T Reactor (Mstr) For Potential Uprate, Thaqal Alhuzaymi, Ayodeji Babatunde Alajo

Nuclear Engineering and Radiation Science Faculty Research & Creative Works

Research reactor is a powerful tool because of its wide contribution, almost to each field of science. It’s considered to be an essential element for advancing research, development and improvement in nuclear industry. The main goal of research reactor is to produce neutrons which are beneficially used for a wide range of applications such as industrial, agricultural, medical, etc. Neutron spectrum impact it uses. Commonly, neutrons with low energy level, up to 0.5 eV, called thermal neutrons where neutrons with intermediate energy level, ranging from 0.5 eV to 0.10 MeV, called epithermal "resonance" neutrons and neutron with high energy level, …

Low-Power Core Reconfiguration For Missouri S&T Reactor (Mstr), Thaqal Alhuzaymi, Ayodeji Babatunde Alajo

Nuclear Engineering and Radiation Science Faculty Research & Creative Works

The Missouri University of Sciences and Technology Reactor (MSTR) is pool-type research reactor which operates up to 200 kilowatt (kW). MSTR used for training and educating nuclear engineering students at Missouri S&T. A several of nuclear researches and irradiation experiments have been conducted in MSTR for example, neutron activation analysis (NAA), neutron radiography, radiolysis, image processing, etc. MSTR initial criticality took place on December 9, 1961. The first power level that MSTR operates at, was 10 kW. The power level alongside the core configuration was upgraded to the current ones, see Fig. 1. MSTR used light-water for moderation and natural …

Calculation And Tabulation Of Efficiencies For Tungsten Foil Positron Moderators, R. Alsulami, M. Albarqi, S. Jaradat, Shoaib Usman, Joseph T. Graham

Nuclear Engineering and Radiation Science Faculty Research & Creative Works

Monte Carlo radiation transport simulations were used to calculate the positron stopping profiles in tungsten positron moderator foils. Stopping profiles were numerically integrated with efficiency kernels derived from Green's function solutions of the 3D diffusion equation to determine the moderation efficiency in both the backscattering and transmission geometries. Stopping profiles and efficiencies were calculated for positron energies from 10 keV to 10 MeV and incident angles from 0° to 75°. The resulting efficiencies agreed with other calculated and measured values in the literature, especially when similar values of the positron diffusion length and surface emission branching ratio were used. Large …

Recent Advances On Carrier And Exciton Self-Trapping In Strontium Titanate: Understanding The Luminescence Emissions, Miguel L. Crespillo, Joseph T. Graham, Fernando Agullo-Lopez, Yanwen Zhang, William J. Weber

Nuclear Engineering and Radiation Science Faculty Research & Creative Works

An up-to-date review on recent results for self-trapping of free electrons and holes, as well as excitons, in strontium titanate (STO), which gives rise to small polarons and self-trapped excitons (STEs) is presented. Special attention is paid to the role of carrier and exciton self-trapping on the luminescence emissions under a variety of excitation sources with special emphasis on experiments with laser pulses and energetic ion-beams. In spite of the extensive research effort, a definitive identification of such localized states, as well as a suitable understanding of their operative light emission mechanisms, has remained lacking or controversial. However, promising advances …

Plenum-To-Plenum Heat Transfer Characteristics Under Natural Circulation In A Scaled-Down Prismatic Modular Reactor, Salman Mohammed Alshehri

Doctoral Dissertations

“Gas-cooled reactor (GCR) is being developed under the Next Generation Nuclear Plant Program (NGNP) in nuclear engineering studies. As the world searches for an energy source with high energy density, clean, abundant, and storable nature to avoid global warming issues, GCR seems to be a promising solution, particularly the possibility of producing hydrogen. Studying and developing the safety analysis and GCR technologies are required for the optimum design and safety of GCR system. Multiphase Reactors Engineering and Applications Laboratory (mReal) at Missouri University of Science and Technology (S&T) has developed a natural convection heat transfer test facility with one riser …

Development Of A Switchable Radioisotope Generator, Kyle Mitchell Paaren

Doctoral Dissertations

The Switchable Radioisotope Generator utilizes alpha-induced reactions to produce a combination of photons, neutrons, and protons with varying fluxes dependent on target materials and source geometry. The activity/strength of the secondary radiation is further controlled by manipulating the number of alpha particles that can interact with the target material(s). Analytical equations were solved to confirm secondary radiation production from target materials using average cross sections from TENDL data. TENDL and JENDL data was confirmed by analytically solving for the total alpha-induced cross sections. This information was used to produce the provisional and utility Patent No: US20190013109A1. TENDL data was then …

Computational Fluid Dynamics Modeling And Comparison Of Advanced Techniques For Heat Transfer Augmentation For Nuclear Applications, Salman Mohammed Alzahrani

Doctoral Dissertations

“Passive safety is the most important feature of NuScale’s reactor designs. Twist tape is one passive heat enhance heat technique. The present research investigated thermo-hydraulic characteristics of natural and forced convection of water under different configurations of twisted tape inserted in tube as well as NuScale rod bundles for uniform wall heat flux using computational fluid dynamics (CFD) using ANSYS Fluent 18.1. Results for twist tape inserted in tube under natural circulation showed that heat transfer enhanced and pressure drop increased to 28% and 102.8% over the plain tube respectively. Regularly spaced tapes, and different widths of the twisted tapes …

Numerical Modeling Study Of A Neutron Depth Profiling (Ndp) System For The Missouri S&T Reactor, Mubarak Mohammed Albarqi

Doctoral Dissertations

”For decades, Neutron Depth Profiling has been used for the non-destructive analysis and quantification of boron in electronic materials and lithium in lithium ion batteries. NDP is one of the few non-destructive analytical techniques capable of measuring the depth profiles of light elements to depths of several microns with nanometer spatial resolution. The technique, however, is applicable only to a handful of light elements with large neutron absorption cross sections. This work discusses the possibility of coupling Particle Induced X-ray Emission spectroscopy with Neutron Depth Profiling to yield additional information about the depth profiles of other elements within a material. …

Design And Characterization Of A Strong Positron Source At The Mstr Beam Port, Raed Atiah Alsulami

Doctoral Dissertations

“For many years, slow positron sources have found uses in diverse fields including medical physics, nuclear physics, biology, surface science, exotic atom research and space science. The purpose of this work is to design and optimize a reactor-based positron source at the Missouri University of Science and Technology Reactor (MSTR) beam port and quantify its intensity. Monte Carlo simulations using the MCNP6 code were used to model the positron production and moderation processes at the MSTR beam port. The thermal neutron flux at the beam port was determined experimentally and used in the source definition of the radiation transport simulations. …

Reactor Configurations To Support Advanced Material Research, Thaqal Mazyad Alhuzaymi

Doctoral Dissertations

"The research goal is to configure a research reactor with multi-spectral capability for advance material research. This required the consideration of high and low-power levels alongside advanced fuel with high physical density and low enriched ²³⁵U. Selected fuel was U-10Mo with 19.75% ²³⁵U enrichment. The fuel and control rods system geometries were adopted from Missouri S&T Reactor (MSTR).

A high-power configuration (HPC) at 2 megawatts and low-power configuration (LPC) at 200 kilowatts were considered. Neutronic performances of the configurations were modeled using Monte Carlo N-particle (MCNP) transport code, version 6. Thermal-hydraulic analysis was performed with ANSYS Fluent. The …

Development And Characterization Of Nanostructured Steels And High Entropy Alloys For Nuclear Applications, Andrew Kalevi Hoffman

Doctoral Dissertations

"Nuclear reactor materials are subjected to a harsh environment including high temperatures and radiation fluences. In order to extend the lifetime of current light water reactors (LWRs) and realize the development of advanced Gen IV nuclear reactors new materials must be developed which can withstand such an environment. This thesis involves two approaches to solving this materials problem: advanced manufacturing of current commercial alloys using severe plastic deformation (SPD) and the development of new advanced high entropy alloys (HEAs).

Because SPD is effective at achieving grain refinement, this technique was used to obtain material having a high volume fraction of …

Experimental Investigation Of Liquid Contact In The Developing Post-Dryout Chf Flow Boiling Regime Using Surface Mounted Thermistors, Hiralkumar Harshadbhai Patel

Doctoral Dissertations

"Understanding heat transfer in the post-critical heat flux (CHF) flow boiling regime is important for determining the performance of the heat transfer equipment for various industrial applications requiring high heat transfer rates, e.g., heat exchangers, boilers, chemical and nuclear reactors. Liquid can be present in the core of the flow channel in the form of entrained liquid droplets, especially immediately downstream of film dryout. These droplets are suspected to provide an important heat transfer mechanism as they impinge on the heated wall. The objective of the current study is to investigate liquid contact with the heated wall in this flow …

Microstructural Evolution Of Zirconium Carbide (Zrcₓ) Ceramics Under Irradiation Conditions, Raul Florez

Doctoral Dissertations

A comprehensive understanding of the microstructural evolution of Zirconium Carbide (ZrC₂) ceramics under irradiation conditions is required for their successful implementation in advanced Gen-IV gas-cooled nuclear reactors. The research presented in this dissertation focusses on elucidating the ion and electron irradiation response of ZrC₂ ceramics. In the first part of the research, the microstructural evolution was characterized for ZrC₂ ceramics irradiated with 10 MeV Au³⁺ ions up to doses of 30 displacement per atom (dpa) at 800 ºC. Coarsening of the defective microstructure, as a function of dose, was revealed by transmission electron microscopy analysis. …

Experimental Investigation On Heat Transfer In A Prismatic Modular Reactor Under Cosine Heat Flux, S. M. Alshehri, I. A. Said, Muthanna H. Al-Dahhan, Shoaib Usman

Chemical and Biochemical Engineering Faculty Research & Creative Works

The current study has investigated natural convection heat during pressurized conduction cooldown (PCC) accident scenario to understand the passive safety features of prismatic modular reactors (PMR) under different intensities of nonuniform center peaking step heat flux distributions (approximating cosine shape) using an advanced fast-response heat transfer technique. A scaled-down PMR module was designed and developed at Missouri S&T by the research team of the Multiphase Reactors Engineering and Applications Laboratory (mReal). The module consists of upper and lower plena connected by heated and cooled channels. Nonuniform heat flux distribution was applied to the heated channel under nonuniform heating center peaking …

Radiation Detector Deadtime And Pile Up: A Review Of The Status Of Science, Shoaib Usman, Amol Patil

Nuclear Engineering and Radiation Science Faculty Research & Creative Works

Since the early forties, researchers from around the world have been studying the phenomenon of deadtime in radiation detectors. Many have attempted to develop models to represent this phenomenon. Two highly idealized models; paralyzable and non-paralyzable are commonly used by most individuals involved in radiation measurements. Most put little thought about the operating conditions and applicability of these ideal models for their experimental conditions. So far, there is no general agreement on the applicability of any given model for a specific detector under specific operating conditions, let alone a universal model for all detectors and all operating conditions. Further the …

Direct Synthesis Of Radioactive Nanoparticles Involving Neutrons, Carlos Henry Castano Giraldo, Maria Camila Garcia Toro, Brian Michael Mills

Nuclear Engineering and Radiation Science Faculty Research & Creative Works

A method to synthesize radioactive nanoparticles includes the production of metallic and multimetallic nanoparticles in a single step by providing an aqueous solution of the metal precursor, and irradiating the aqueous solution thereby producing nanoparticles. The obtained nanoparticles include one or more radioactive isotopes of gold, such as 198Au and 199Au as well as radioisotopes of silver when the obtained nanoparticles are bimetallic. The aqueous solution is irradiated in a radiation field that includes neutrons and gamma rays. The radiation field may be provided by a nuclear reactor. The aqueous solution may include silver, and bimetallic nanoparticles may be produced. …