Nuclear Engineering Commons^™

An Ionization Chamber For High Resolution Fission Product Spectroscopy, James Cole

Nuclear Engineering ETDs

The fission process has played a vital role in the world’s search for effective sources of alternative energy. With almost 80 years of work with fissionable material there is still much that is unknown about the process. Fission fragment mass and atomic number distributions are still lacking in completeness and critical detail. Knowledge of this information is highly sought after in the effort to improve various fields of nuclear physics and engineering such as reactor design, predictive models, waste disposal methods, and an overall understanding of the fission process. In an effort to better understand this process, we have developed …

Characteristics Of Thick Concrete Neutron Reflection, Richard Gordon Taylor

Doctoral Dissertations

Water is considered as a neutron reflector in nuclear criticality safety evaluations because it is readily available and easily forms a close-fitting shape around fissile material. Concrete is commonly encountered industrial environments and can be a more effective reflector than water. Nuclear criticality safety literature reporting experimental and analytical studies involving concrete as a reflector from the 1950’s to the present was reviewed. Nuclear criticality safety community perspective on concrete reflection has evolved from acknowledgement that concrete is a reflector through recognition that concrete can be a more effective reflector than water to current interest in identifying which constituents are …

Deterministic Neutron Transport And Multiphysics Experimental Safety Analyses At The High Flux Isotope Reactor, Christopher James Hurt

Doctoral Dissertations

The computational ability to accurately predict the conditions in an experiment under irradiation is a valuable tool in the operation of a research reactor whose scientific mission includes isotope production, materials irradiation, and neutron activation analysis. Understanding of different governing physics is required to ascertain satisfactory conditions within the experiment: the neutron transport behavior throughout the reactor and the coupled behavior of heat transfer, structural mechanics and fluid flow. Computational methods and tools were developed for robust numerical analysis of experiment behavior at the Oak Ridge National Laboratory (ORNL) High Flux Isotope Reactor (HFIR), including fully-coupled thermo-mechanics in three plutonium-238 …

Development, Synthesis, And Analysis Of Surrogate Post-Detonation Nuclear Melt Glass, Andrew Vincent Giminaro

Doctoral Dissertations

With the threats facing the world today, there is an ever-increasing need for training the the fields of radiochemistry and nuclear forensics. Training and research in these fields requires reference materials that accurately represent materials that could potentially be encountered. Unfortunately, many of the historical samples of debris from nuclear weapons tests remains classified. Because of this, there is a need for realistic surrogates. This research focuses on the development of surrogates for the bulk and particulate nuclear melt glass that is expected to be found in an urban setting after a nuclear event.

A mathematical model for the creation …

Beta-Delayed Neutron Data And Models For Scale, Kemper Dyar Talley

Doctoral Dissertations

Recent advancements in experimental and theoretical nuclear physics have yielded new data and models that more accurately describe the decay of fission products compared to historical data currently used for many applications. This work examines the effect of the adopting the Effective Density Model theory for beta-delayed neutron emission probability on calculations of delayed-neutron production and fission product nuclide concentrations after fission bursts as well as the total delayed neutron fraction in comparison with the Keepin 6-group model. We use ORIGEN within the SCALE code package for these calculations. We show quantitative changes to the isotopic concentrations for fallout nuclides …

Algorithms And Methods For Optimizing The Spent Nuclear Fuel Allocation Strategy, Gordon Matthew Petersen

Doctoral Dissertations

Commercial nuclear power plants produce long-lasting nuclear waste, primarily in the form of spent nuclear fuel (SNF) assemblies. Spent fuel pools (SFP) and canisters or casks that sit at an independent spent fuel storage installation (ISFSI) at the reactor site store the fuel assemblies that are removed from operating reactors. The federal government has developed a plan to move the SNF from reactor sites to a Consolidated Interim Storage Facility (CISF) or a geological repository. In order to develop a predictable pick-up schedule and give utilities notice of an impending pickup from a reactor site, the federal government developed a …

Development Of Instrumentation And Control Systems For An Integral Large Scale Pressurized Water Reactor, Matthew Rowland Morrow Lish

Doctoral Dissertations

Small and large scale integral light water reactors are being developed to supply electrical power and to meet the needs of process heat, primarily for water desalination. This dissertation research focuses on the instrumentation and control of a large integral inherently safe light water reactor (designated as I²S-LWR) which is being designed as part of a grant by the U.S. Department of Energy Integrated Research Project (IRP). This 969 MWe integral pressurized water reactor (PWR) incorporates as many passive safety features as possible while maintaining competitive costs with current light water reactors. In support of this work, the …

Preliminary Investigation For The Development Of Surrogate Debris From Nuclear Detonations In Marine-Urban Environments, Adam G. Seybert

Masters Theses

No nuclear weapon has ever been detonated in a United States city. However, this also means the nuclear forensic community has no actual debris from which to develop analytical methods for source attribution, making the development of surrogate nuclear debris a vital undertaking. Moreover, the development of marine-urban debris presents an unusual challenge because unlike soil and urban structures, which remain compositionally consistent, the elemental composition of harbor and port waters fluctuates considerably due to natural phenomenon and human activity. Additionally, marine vessel composition and cargo can vary dramatically. While early US nuclear tests were carried out in shallow-water coastal …

A Bayesian Approach To Aerial Localization Of Radioactive Sources, Robert Blake Wilkerson

Masters Theses

Securing nuclear material has become an important area for the safety of the U.S. and other countries. Within nuclear security, there is a potential to use orphaned or stolen radioactive sources to cause harm. As the amount of radioisotopes used by government and commercial businesses increases, the need to secure these sources becomes exponentially more difficult. It is well known that there have been several cases of lost, orphaned or stolen nuclear sources across the globe. There is a need for state-of-the-art radiation search methods to search for these potentially dangerous radioactive sources that could be misplaced. While there are …

Proton Therapy Facility Shielding, Hadyn M. Daugherty, Isaac C. Waaldschlager, Daniel S. Elkins, Alyxandria Wszolek, Rachel N. Gaudet

Chancellor’s Honors Program Projects

No abstract provided.

Accelerator Shielding For A Bee Hive Irradiator, Robert F. Turner, Matthew O'Neil, Victoria Martin, Saya Rutherford, Danielle Mcfall, Ali Buhamad

Chancellor’s Honors Program Projects

No abstract provided.

Doppler Temperature Coefficient Calculations Using Adjoint-Weighted Tallies And Continuous-Energy Cross Sections In Mcnp6, Matthew A. Gonzales

Nuclear Engineering ETDs

The calculation of the thermal neutron Doppler temperature reactivity feedback co- efficient, a key parameter in the design and safe operation of advanced reactors, using first order perturbation theory in continuous energy Monte Carlo codes is challenging as the continuous energy adjoint flux is not readily available. Traditional approaches of obtaining the adjoint flux attempt to invert the random walk process as well as require data corresponding to all temperatures and their respective tem- perature derivatives within the system in order to accurately calculate the Doppler temperature feedback.

A new method has been developed using adjoint-weighted tallies and On-The-Fly (OTF) …

Measurement And Analysis Of Iii-V & Ii-Vi Infrared Detectors: Radiometric, Noise Spectrum, And Radiation Tolerance Performance, Vincent M. Cowan

Nanoscience and Microsystems ETDs

Infrared (IR) hybrid detector arrays and discrete detectors operated in the space environment may be subjected to a variety of sources of natural radiation while in orbit. This means IR detectors intended for applications such as space-based intelligence, surveillance, and reconnaissance (ISR) or space-situational awareness (SSA) must not only have high performance (high quantum efficiency, h and low dark-current density, J_D, and preferably minimal 1/f noise content), but also their radiation tolerance or ability to withstand the effects of the radiation they would expect to encounter in space must be characterized and well understood. As the effects of …

Fokker-Planck-Based Acceleration For Sn Equations With Highly Forward Peaked Scattering In Slab Geometry, Japan K. Patel

Nuclear Engineering ETDs

Short mean free paths are characteristic of charged particles. High energy charged particles often have highly forward peaked scattering cross sections. Transport problems involving such charged particles are also highly optically thick. When problems simultaneously have forward peaked scattering and high optical thickness, their solution, using standard iterative methods, becomes very inefficient. In this dissertation, we explore Fokker-Planck-based acceleration for solving such problems.

Advanced Stochastic Collocation Methods For Polynomial Chaos In Raven, Paul W. Talbot

Nuclear Engineering ETDs

As experiment complexity in fields such as nuclear engineering continually increases, so does the demand for robust computational methods to simulate them. In many simulations, input design parameters and intrinsic experiment properties are sources of uncertainty. Often small perturbations in uncertain parameters have significant impact on the experiment outcome. For instance, in nuclear fuel performance, small changes in fuel thermal conductivity can greatly affect maximum stress on the surrounding cladding. The difficulty quantifying input uncertainty impact in such systems has grown with the complexity of numerical models. Traditionally, uncertainty quantification has been approached using random sampling methods like Monte Carlo. …

Reduced-Order Monte Carlo Modeling Of Radiation Transport In Random Media, Aaron J. Olson

Nuclear Engineering ETDs

The ability to perform radiation transport computations in stochastic media is essential for predictive capabilities in applications such as weather modeling, radiation shielding involving non-homogeneous materials, atmospheric radiation transport computations, and transport in plasma-air structures. Due to the random nature of such media, it is often not clear how to model or otherwise compute on many forms of stochastic media. Several approaches to evaluation of transport quantities for some stochastic media exist, though such approaches often either yield considerable error or are quite computationally expensive. We model stochastic media using the Karhunen-Loève (KL) expansion, seek to improve efficiency through use …

Out From Darkness And Into The Light: The Role Of Transparency And Social Media In Government, Frances Nichols Bachstein

Doctoral Dissertations

Government agencies that protect secrecy often have a difficult time connecting to the public. Secretive, or perceived secretive government organizations often fall into the nebulous realm of uncertainty for the information consumer. This results in a great deal of misinformation and disinformation being thought of as correct. Since 2008, the US government is moving toward a more transparent, open, and easily accessed information base through social media. Agencies across the government are adopting types of social media communication. However, bureaus that primarily focus on security and safeguarding secrets struggle with how much disclose, which platforms of social media are the …

A Generalized Method For Fissile Material Characterization Using Short-Lived Fission Product Gamma Spectroscopy, Justin Richard Knowles

Doctoral Dissertations

Characterizing the fissile content of nuclear materials is of particular interest to the safeguards and nuclear forensics communities. Short-lived fission product gamma spectroscopy offers a significant reduction in analysis time and detection limits when compared to traditional non-destructive assay measurements. Through this work, a fully generalizable method that can be applied to variations in fissile compositions and neutron spectra was developed for the modeling and measurement of short-lived fission product gamma-rays. This method uses a 238-group neutron flux that was characterized for two pneumatic tube positions in the High Flux Isotope Reactor using flux monitor irradiations. This flux spectrum was …

Characterizing Local Order And Physical Properties Of Rare Earth Complex Oxides, Thomas Jacob Shamblin

Doctoral Dissertations

With more than 500 compositions, materials possessing the pyrochlore structure have a myriad of technological applications and physical phenomena. Three of the most noteworthy properties are the structure’s ability to resist amorphization making it a possible host matrix for spent nuclear fuel, its exotic magnetic properties arising from geometric frustration, and fast ionic conductivity for solid-oxide fuel cell applications. This work focuses on these three aspects of the pyrochlore’s many potential uses. Structural characterization revealed that pyrochlore-type oxides have a tendency to disorder from a high symmetry cubic structure to a lower symmetry orthorhombic arrangement in response to a variety …

Actinium-225 Production Via Proton Irradiation Of Thorium-232, Justin Reed Griswold

Doctoral Dissertations

High energy proton spallation reactions on natural thorium metal targets have been utilized to produce multi mCi [milliCurie] quantities of Actinium-225. Theoretical cross sections for actinium and thorium isotopes as well as for a select number of the fission products produced in these reactions were generated by the Monte Carlo radiation transport code PHITS to simulate the experimental data obtained from sixteen irradiations of thorium metal targets with 25-210 µA [microampere] proton beams ranging in energies from 77 to 192 MeV. Irradiations were conducted at Brookhaven National Laboratory (BNL) and Los Alamos National Laboratory (LANL), while target dissolution and processing …

X-Ray Fluorescence For Quantification Of Lead And Strontium In Vivo, Aaron James Specht

Open Access Dissertations

Lead (Pb) is a toxicant well known for its effects on almost every organ system in the body. Pb use in industry has declined since removal of Pb from gasoline, but many developing countries still have significant use of Pb. Exposure to Pb has been linked with diseases causing neurodegeneration and thus have lasting effects long after the initial exposure. Another metal, strontium (Sr), has been linked with bone disease in particular situations and shown to have uses in treating osteoporosis as a supplement. However, there are no studies of the effects of Sr using a meaningful biomarker. The most …

Bayesian Framework For High Confidence Signal Validation For Online Monitoring Systems In Nuclear Power Plants, Anjali Muraleedharan Nair

Masters Theses

Online Monitoring systems may offer an effective alternative to the current intrusive calibration assessment procedure used in the nuclear industry. Apart from optimizing the economic and human resource aspects of the currently utilized technique, OLM increases the opportunities for performance assessment and fault detection for nuclear instrumentation. This can lead to possibly extend or ultimately remove the current time based assessment process. Irrespective of its plausible benefits, OLM sees limited applicability in today’s US fleet. Regulatory constraints that limits the large scale implementation of OLM can be addressed by developing highly sensitive signal validation technique and thereby structurally quantify its …

Development Of A National Human Reliability Program (Hrp) Model For An Emerging Nuclear Country: Nigerian Case Study, Stephen Olumuyiwa Ariyo Dahunsi

Masters Theses

The current demand for electricity and concern of the climate change in emerging countries has led to the rise in the number of nations adopting nuclear technology options. Besides this, the global rise in terrorism and the existence of credible threats in Nigeria and other emerging countries embarking on nuclear program for peaceful application may pose a critical challenge in implementation of this technology. Furthermore, the dual threat issue of providing electricity, while inadvertently producing weapon and radiological material that could similarly undermine international security must be mitigated. In order to achieve the mitigation target, it is highly important to …

Thermoelectric Half-Heuslers: Synthesis, Processing, And Performance, Joseph Robert Croteau

Boise State University Theses and Dissertations

Thermoelectric half-Heusler compounds have potential to convert the heat wasted from industrial and transportation processes to useful electricity. Among the highest performing half-Heusler compounds are nano-structured bulk materials which have been arc-melted, pulverized into a nano-powder, and sintered by DC-hot press. High performing n- and p-type half-Heusler compounds with nominal composition of Hf_0.25Zr_0.75NiSn_0.99Sb_0.01 and Nb_0.75Ti_0.25FeSb, respectively, have been provided to us in both dense and powder form by our collaborators at the University of Houston. We consolidate these powders by SPS, refine these powders to improve both particle size …

Thin Film Alsb Carrier Transport Properties And Room Temperature Radiation Response, Erin Vaughan

Nuclear Engineering ETDs

Theoretical predictions for AlSb material properties have not been realized using bulk growth methods. This research was motivated by advances in molecular beam epitaxial (MBE) growth technology to produce high-quality thin-film AlSb for the purpose of evaluating transport properties and suitability for radiation detection. Simulations using MCNP5 were performed to benchmark an existing silicon surface barrier detector and to predict ideal AlSb detector behavior, with the finding that AlSb should have improved detection efficiency due to the larger atomic number of Sb compared with Si. GaSb diodes were fabricated by both homoepitaxial MBE and ion implantation methods in order to …

Particle Entrainment Studies From Dry And Wet Bed, Saber Ayatollahi

Electronic Thesis and Dissertation Repository

During the Fluid Coking Process™ bitumen is sprayed into a fluidized bed of hot coke particles. The bitumen undergoes thermal cracking and is converted into gasses, condensable vapors, and solid coke, which deposits on the coke particles. These vapors rise through the vessel and result in entrainment of coke particles. Wet fine coke particles from the freeboard region enter the cyclone and contribute to the fouling of the Coker cyclones which can lead to the premature shut-down of Fluid Cokers.

The primary objective of this research is to determine how bed wetness affects entrainment.

First, a new fluidized bed was …

Cyclotron Production And Biomedical Imaging Applications Of The Pet Isotope Manganese-52, Andrew Lake Wooten

McKelvey School of Engineering Theses & Dissertations

Manganese is an important element for biomedical research because of its roles as an essential micronutrient and as a neurotoxin from chronic elevated exposure, as well as the role of manganese(II) as a paramagnetic core for contrast agents in T1-weighted magnetic resonance imaging (MRI). Using a radiotracer of manganese provides excellent sensitivity for studying these phenomena, but only 52Mn met the criteria for our experiments: (1) a half-life (t1/2=5.6 days) that was long enough to examine timepoints over several days, (2) a half-life that was short enough to emit sufficient counts for a realistic scan time, and (3) emitted radiation …

Control System Requirements For A Nuclear Thermal Propulsion System, Adam Hasse, Michael Smith, Bradley Pershke, Andrew Adams, Stephen GilliAm

Chancellor’s Honors Program Projects

No abstract provided.

The Design Of A Fast Neutron Radiography System For Non-Destructive Analysis Of Thick, Dense Objects, Alicia Lauren Swift

Doctoral Dissertations

This dissertation describes the development of a novel time-of-flight (TOF) fast neutron radiography system, TiGReSSE ("Time Gating to Reject Scatter and Select Energy"), for non-destructive analysis of thick, dense objects, such as a spent nuclear fuel cask. Such objects create large scatter fields that mask interior flaws in an image, and are impenetrable with traditional x-ray or low-energy neutron radiography. By using a fast pulsed, high-energy monoenergetic neutron source with TiGReSSE, TOF methods may be employed to completely reject this problematic scatter. If using TOF methods with a fast pulsed, high-energy polyenergetic neutron source instead, partial scatter rejection is possible, …

Adopting 3d Time-Of-Flight Sensing Technology For Design Information Verification In International Safeguards, Matthew Stephen Duchene

Doctoral Dissertations

International safeguards inspectors periodically perform examinations at sensitive nuclear facilities to verify that the facilities’ designs, layouts, and functions are identical to information declared to the International Atomic Energy Agency (IAEA). Such design information verification (DIV) relies on tools and techniques—such as 3D laser range-finding (3DLR) with light detection and ranging (LIDAR) instruments—that are resource intensive. This research explores 3D Time-of-Flight (TOF) sensors as a possible alternative technology to LIDAR systems for performing spatial change-detection to enhance the DIV process.

This research uses the Microsoft Kinect Version 2 (Kinect v2) camera system, one of several commercial depth-sensing instruments that is …