Nuclear Engineering Commons^™

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 …

Radiation Effects In Metal Oxides And Carbides, Benjamin Jackson Cowen

Nuclear Engineering ETDs

MD simulations of SiO₂, TiO₂, Cr₂O₃, Al₂O₃, MgO, and SiC, are performed to: (a) calculate TDE probability distributions and dependence on crystallographic direction, and (b) determine the number and types of defects formed with low- and high-energy PKAs and projectiles. In addition, a qualitative comparison of the MD simulation results of radiation damage in TiO₂, MgO, and crystalline and amorphous SiC thin films are compared with those of in situ TEM ion beam irradiation experiments at the Sandia National Laboratories’ I³TEM facility.

The TDE …

Neutron Spectroscopy Using Rubberized Eu:Licaf Wafers, Michael A. Ford

Theses and Dissertations

With the increasing cost and decreasing availability of ³He, there have been many efforts to find alternative neutron detection materials. Lithium calcium aluminum fluoride (LiCAF) enriched to 95% ⁶Li doped with europium was evaluated here as a replacement material for ³He, based on the absorption of thermalized neutrons by the ⁶Li and subsequent energy release of the ⁶Li(n,t)⁴He reaction. Wafers 0.5 cm thick, consisting of LiCAF crystals in a rubberized matrix, were embedded with wavelength shifting fibers (WSF) and mated to silicon photo-multipliers (SiPMs) to measure the photon response in a flux of …

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. …

Spin Alignment Generated In Inelastic Nuclear Reactions, Daniel Hoff

Arts & Sciences Electronic Theses and Dissertations

The spin alignment of inelastically excited 7Li projectiles, when the target remains in its ground state, was determined through angular-correlation measurements between the breakup fragments of 7Li_ (_ + t). It was found that 7Li_ is largely aligned along the beam axis (longitudinal) in this type of inelastic reaction, regardless of the target. This longitudinal alignment is well described by DWBA calculations, which can be explained by an angular-momentum-excitation-energy mismatch condition. These calculations also explain the longitudinal spin alignment of excited nuclei in several other systems, showing the phenomenon is more general. The experiment involving 7Li was performed at the …

Incorporating Collisions And Resistance Into The Transition From Field Emission To The Space Charge Regime, Samuel D. Dynako, Adam M. Darr, Allen L. Garner

The Summer Undergraduate Research Fellowship (SURF) Symposium

Advancements in microelectromechanical systems (MEMS) and microplasmas, particularly with respect to applications in combustion and biotechnology, motivate studies into microscale gas breakdown to enable safe system design and implementation. Breakdown at microscale deviates from that predicted by Paschen’s law due to field emission—the stripping of electrons from the cathode in the presence of strong surface field—and follows the Fowler-Nordheim (FN) law. As injected current increases at this length scale, electrons accumulate in the gap and FN electron emission becomes space charge limited, leading to the Child-Langmuir (CL) law at vacuum and the Mott-Gurney (MG) law at high pressure. While theoretical …

A Security Approach For The Example Sodium Fast Reactor, Christian X. Young, Robert S. Bean

The Summer Undergraduate Research Fellowship (SURF) Symposium

Increases in the spread of nuclear technology and the rise of non-state terrorism in the modern era has proved the need for effective security approaches to new nuclear facilities. Many documents about security approaches for nuclear plants are non-public material, however, making it difficult to teach others about the basics of security design. To alleviate this issue, we used available texts in the security realm to design a security approach for the Generation IV International Forum’s Example Sodium Fast Reactor. Our approach utilized infrared, microwave, fiber optic, and other advanced technologies to provide security for the special nuclear material present. …

Pnnl Dark Matter Bubble Chamber, Ryan Robinson

STAR Program Research Presentations

The Pacific Northwest National Laboratory (PNNL) prototype bubble chamber is intended to address issues encountered with the current PICO dark matter search detectors and improve the functionality of future experimental designs. The PNNL bubble chamber accomplishes this with a simplified interface between the hydraulic pressure controls and the target vessel and altering the standard chamber design such that it can be easily exchanged and replaced with vessels of various sizes and materials for testing purposes. The chamber itself is a glass vessel which houses perfluorobutane and holds the target fluid above room temperature and atmospheric pressure. The target fluid becomes …

Sonomechanical Enhanced Sparging Techniques For Advanced Reactor Applications, Floren V. Rubio

Nuclear Engineering ETDs

The fluoride salt cooled high temperature reactor (FHR) is a Generation IV advanced reactor design that has potential to produce efficient, low carbon, and safe energy. But, there are significant engineering challenges that need to be addressed before the deployment of this reactor. One of the key challenges is tritium release mitigation and sequestration. Because the FHR utilizes a eutectic LiF-BeF2 (flibe) salt as a coolant, the coolant is a significant source of tritium.

High-power ultrasonics have been used in many industrial process streams such as food processing, metal production, chemical production, and pharmaceutical manufacturing. Techniques and concepts from these …

Recommended Corrective Security Measures To Address The Weaknesses Identified Within The Shapash Nuclear Research Institute, Khadija Moussaid, Oum Keltoum Hakam

International Journal of Nuclear Security

The Shapash Nuclear Research Institute (SNRI) data book was issued by the International Atomic Energy Agency (IAEA) in 2013. The hypothetical facility data book describes the hypothetical site, which is divided into two areas: the low-security area, known as the administrative area, and the very high-security area, known as the protected area. The book contains detailed descriptions of each area’s safety and security measures, along with figures of multiple buildings in both areas, and also includes information about the site’s computer networks.

This paper aims to identify security weaknesses related to the institute’s location, the Administrative Area (AA), the Protected …

Radiation Effects In Apatite And High Entropy Alloy Under Energetic Ions And Electrons, Jianren Zhou

LSU Doctoral Dissertations

Radiation effects in apatite and high entropy alloy under energetic ions and electrons are studied in this doctoral dissertation to develop advanced crystalline ceramic waste forms and nuclear structural materials. Apatite is proposed as a ceramic waste form for the immobilization of radionuclides, but its performance is strongly affected by the irradiation of the incorporated radionuclides. It is thus important to understand the radiation effects in apatite structure and the underlying physics. Effects of chemical composition, grain size, interfacial structure, as well as radiation conditions on the microstructural evolution, phase transformation and damage mechanisms of apatite under alpha-decay and beta-decay …

The Continuing Quest For Missile Defense: When Lofty Goals Confront Reality, Peter J. Pella

Gettysburg College Faculty Books

For almost three quarters of a century, the United States has spent billions of dollars and countless person-hours in the pursuit of a national missile defense system that would protect the country from intercontinental ballistic missiles (ICBM) carrying nuclear warheads. The system currently in place consists of 44 long-range antiballistic missiles stationed in Alaska and California to protect the United States from a possible nuclear weapon carrying ICBM attack from North Korea. After all this effort, this system is still imperfect, being successful only 10 out of 18 tests.

This book will provide an historical description of past efforts in …

Actinium-225 Production Via Different Irradiation Beams Of Thorium-232, Naser Burahmah

Nuclear Engineering Reports

No abstract provided.

Molecular Dynamics Simulations Of Hydrogen Diffusion And Retention Behavior Near Sub-Surface Defects In Tungsten: Towards Predicting Tritium Retention In The Iter Divertor, Emily Nicole Hutchins

EURēCA: Exhibition of Undergraduate Research and Creative Achievement

Molecular Dynamics Simulations of hydrogen diffusion and retention behavior near subsurface defects in tungsten: Towards predicting tritium retention in the ITER divertor

Plasma-facing components within fusion reactors will be exposed to massive particle and thermal loads, which will pose serious material challenges. The plasma-facing component of interest in this project is the divertor, a device that allows for the online removal of the helium reaction product from the deuterium – tritium plasma. The ITER divertor will be constructed from tungsten, which is also a prime candidate for use in future demonstration fusion reactors, because of its superior mechanical properties and …

X-Means Clustering Implementing The Gap Statistic For Multiple Positron Emission Particle Tracking, Matthew Herald

EURēCA: Exhibition of Undergraduate Research and Creative Achievement

The most efficient and accurate method for clustering Coincidence Lines (CL) for Positron Emission Particle Tracking (PEPT) is undetermined. A number of methods have been created to perform this task. A novel clustering method featuring x-means is presented using an automated k-value estimator for k-means clustering. Gap statistic is used to select the best k-value. Geant4 Application for Tomographic Emission is used to simulate particles of 50 µCi and the detection and electronic chain associated with the Siemens Inveon Pre-Clinical Scanner. The simulation produces an array of coincident lines (CL) in a format consistent with scanner output. The CL are …

Detector Arrays For Nuclear Security And Safeguards Applications, Jessica Hartman

UNLV Theses, Dissertations, Professional Papers, and Capstones

Over the last two decades it has become increasingly apparent that there is a need for new technologies capable of reliable and efficient fast neutron detection. As national and international stockpiles of 3He continue to dwindle, the need to find a new gold standard of neutron detection becomes more critical. Moreover, neutrons are generated typically in the MeV energy range. The use of 3He detectors for fast neutron measurements requires the use of moderators. Detector arrays capable of fast neutron detection are one solution to this problem. To this end, the focus of this work was the study of detector …

Analysis Of Double-Wall And Twisted-Tube Heat Exchanger Concepts For Use In Fluoride Salt-Cooled High-Temperature Reactors, Bryan M. Wallace

Nuclear Engineering ETDs

Fluoride Salt-cooled High-temperature Reactors (FHRs) are an attractive fourth generation reactor concept. Like other fourth generation concept designs, FHRs offer characteristics such as a high-temperature low-pressure molten salt coolant allowing the reactor to be combined with a high-temperature high-efficiency power generation cycle such as an air-Brayton or supercritical carbon dioxide (SCO2). \par

Like most Gen IV reactor concepts, there are a few problems which need to be addressed with the design before it can be licensed. One particular design is the Mark 1 pebble bed FHR, a design put out by the University of California Berkeley. Two problems that need …

Irradiation Experiment For Living Insect-Based Radiological Dispersal Device, Braden Goddard, Walid Metwally, Ahmad Ababneh

International Journal of Nuclear Security

People generally associate fear with “nuclear”, “radioactive” and “insects”. It is speculated that a release of radioactive living insects would instill more fear into the general public than a “traditional” style radiological dispersion device (RDD). This paper evaluates the potential threat of an insect-based RDD using experimental data. The results of this project found that insect-based RDDs are an insignificant threat due to the challenges in making insects radioactive enough to pose any danger to humans without killing the insects.

Scintillator-Based Uav, Austin Mullen, Chris Haseler, Sarah Davis, Brooke Mcmurrer, Tanner Jefferies, Peyton Lara

Chancellor’s Honors Program Projects

No abstract provided.

Design And Characterization Of Systems For Direct Spatial Imaging Of Low-Energy Gamma-Radiation Sources, Phoenix Baldez

Nuclear Engineering ETDs

This work describes the development of radiation detection systems to identify and image special nuclear material (SNM) using low energy gamma rays. The imaging of these materials is crucial for timely, in the field responses to potential threats to national security. Using a spectroscopy system, the sources can be identified while images can be produced concurrently for the sources which are present. Two systems were designed and characterized in this study, a collimated imager which used collimation in front of a small CdTe detector, and a pixelated pinhole imager, using a pinhole mask in front of a pixelated CZT detector. …

Developing Kenya’S Educational Capacity In Nuclear Security Through Nuclear Forensics Research, Hudson Kalambuka Angeyo

International Journal of Nuclear Security

Nuclear energy’s distinctive characteristics give rise to special educational requirements. These requirements are necessary to not only address the danger of nuclear proliferation, but also to build capacity for a secure nuclear fuel circle. In this paper, I assess the status of educational capacity in nuclear security both in response to, and in support of, Kenya’s nuclear power program. I highlight the nuclear security educational infrastructure’s key features in the context of nuclear power, noting the low capacity at Kenyan universities. I identify the steps required to ensure that the country’s dynamic nuclear regulatory infrastructural framework is used effectively to …

An Exploration Of The Optical Detection Of Ionizing Radiation Utilizing Modern Optics Technology, Sean D. Fournier, Adam Hecht, Cassiano De Oliveira, Jeffrey B. Martin, Richard K. Harrison, Charles Potter

Nuclear Engineering ETDs

Modern ultraviolet (UV) cameras, when combined with UV-transmitting lenses/filter arrangements, can be used to detect radiation dose in air. Ionizing radiation excites nitrogen molecules in ambient air, the resulting decay includes weak emission of ultraviolet photons. Previous work has proven this phenomenon is detectable using highly-sensitive electronically cooled cameras traditionally used in astronomy for low-background imaging. While the ability to detect the presence of radiation (i.e. qualitative measurement) has been demonstrated at Sandia National Laboratories, there are several challenges in correlating images to known dose-fields (quantitative measurement). These challenges include: a low signal to background ratio, interferences due to electronic …

Patient Specific Radiation Doses From Projection Radiography Images: Improving The Accuracy Of Low Dose Radiation Calculations, Daniel J. Sandoval

Nuclear Engineering ETDs

Due to an increase in regulatory scrutiny and medical facility accreditation requirements to monitor patient radiation dose from diagnostic imaging procedures, there is a growing necessity to determine and record accurate patient radiation dose from diagnostic medical imaging procedures. Current methods of patient dosimetry in diagnostic imaging are both extremely difficult and time consuming, require large computing resources (such as Monte Carlo computations), or lack accuracy due to using data based on homogeneous materials and “standard-man sized” anthropomorphic models.

This dissertation provides an algorithm that calculates a more accurate dose using patient-specific projection radiographic images. The algorithm includes measurements acquired …

Case Study On The Development Of Engineering Design Modification Projects For U.S. Nuclear Power Plants: A Knowledge Retention Tool In Support Of The Longevity And Resilience Of The Nuclear Power Industry, Pamela M. Torres-Jiménez

Engineering Management & Systems Engineering Theses & Dissertations

The nuclear power industry in the United States (U.S.) has gone through various changes throughout its history. Most recently, plans to grow the industry through the construction of new power plants have ceased. Because of this, the industry is at a period where the longevity and resilience of existing nuclear power plants are vital to its subsistence.

One of the ways existing nuclear power plants can assure longevity and resilience is by performing engineering design modifications efficiently and at a lower cost. Strategic plans, such as the Delivering the Nuclear Promise, can support nuclear utilities to achieve this. Another strategy …

Development Of A Novel Framework For The Application Of Signature Based Safeguards (Sbs) To Pyroprocessing, Philip Leo Lafreniere

Nuclear Engineering ETDs

Traditional nuclear material accountancy (NMA) faces several challenges when applied to pyroprocessing facilities. To address these challenges, alternative methods of safeguarding nuclear material are being developed. One method is process monitoring (PM). PM involves taking operational process data and applying it to safeguards using an advanced framework. Signature Based Safeguards (SBS), a proposed PM framework, involves the identification of anomalous scenarios and the subsequent identification and detection of their respective PM signatures from a system of measurements. SBS has previously focused on failure modes that result in transfer of mass to unexpected places in the mass flowsheet. This work developed …

The "Double Standard" Of Nonproliferation: Regime Type And The U.S. Response To Nuclear Weapons Program, Alina Shymanska

International Journal of Nuclear Security

There is no doubt that the NPT regime is far from being equal for all states involved. As the predominant hegemonic power since WWII, the United States plays a major role in deciding the fates of non-great power proliferators. This article tries to find the logical explanation of the phenomenon whereby some nuclear proliferators are absolved regardless of their active accumulation of nuclear arsenals while others are labeled as “rogue states” and ordered to disarm. The article suggests that a particular proliferator’s political regime could affect the way in which its state is approached by the U.S., known for its …

A Cfd Assisted Closed-Loop Control System Design For The 37-Element Canadian Scwr Under Full Load Condition, Huirui Han

Electronic Thesis and Dissertation Repository

A method to design the closed-loop control system for the 37-element vertical Canadian supercritical water-cooled reactor (SCWR) fuel bundle has been proposed in this study. The dynamic models used in the controller design are obtained based on the computational fluid dynamics (CFD) simulations of the fluid flow and heat transfer of the supercritical water in the SCWR fuel bundle. The Reynolds Stress Model is used in the CFD simulations. Comparisons of the supercritical water flow behaviors and heat transfer phenomenon in the single- rod channel and multi-rod channel are also carried out. The results show that there are secondary flows …

Neutronics Studies On The Nist Reactor Using The Ga Leu Fuel, Kyle A. Britton

Theses and Dissertations

The National Bureau of Standards Reactor (NBSR) located on the National Institute of Standards and Technology (NIST) Gaithersburg campus, is currently underway of fuel conversion from high enriched uranium (HEU) fuel to low enriched uranium (LEU) fuel. One particular challenging part of the conversion of the NBSR is the high average flux level (2.5×10¹⁴ n/cm²-s) required to maintain experimental testing capabilities of the reactor, without significant changes to the external structures of the reactor. Recently the General Atomics (GA) Training Research Isotopes General Atomics (TRIGA) fuel has shown some promising features as a LEU candidate for the …

Lanthanide-Based Core-Shell Nanoparticles As Multifunctional Platforms For Targeted Radionuclide Therapy And Multimodal Molecular Imaging, Miguel Toro-Gonzalez

Theses and Dissertations

Lanthanide phosphate (LnPO₄) and lanthanide vanadate (LnVO₄) nanoparticles (NPs) are promising platforms for theranostic applications because of their chemical stability, low solubility, low toxicity, and unique luminescence and magnetic properties. Motivated by the high radiation resistance and ability to host actinides of naturally occurring lanthanide-based compounds, LnPO₄ and LnVO₄ NPs were studied as radionuclide carriers for targeted radionuclide therapy using in vivoα-generators, ²²³Ra, ²²⁵Ac, and ²²⁷Th. The implementation of these radionuclides has shown potential for the treatment of micrometastases and solid tumors as well as challenges in the retention of …