Nuclear Engineering Commons^™

The Future Of Nuclear Security: A Medical Physicist’S Perspective, Katharine E. Thomson

International Journal of Nuclear Security

Planning for the future of nuclear security is a vital and complex task, requiring cooperation and contribution from many disciplines and industries. This diversity of expertise should include the medical sector, which faces many of the same challenges as the nuclear industry: controlling access to dangerous material, creating a strong security culture, cooperating with the wider world and engaging the public.

Medical physicists, of which the author is one, oversee all aspects of small-scale radiation use. This paper discusses three key areas increasingly important to both medical and nuclear uses of radioactive materials: public engagement, prevention of nuclear and radiological …

Assessing And Enhancing Nuclear Safety And Security Culture For Small Facilities That Handle Radioactive Material, Solymosi Máté

International Journal of Nuclear Security

The use of radioactive sources is expanding all over the world and abreast the necessity of the enhancement of its safe and secure application is increasing too. In the nuclear industry, the safety and security are top priorities since decades. They share the same goal, to protect humans from the negative affect of the ionizing radiation. The human component of them is a significant factor and technical solutions can protect us so far and thus the culture for safety and security become a major focus. On the other hand, there are still some contradiction between recommendations and international guidance of …

The Future Of Nuclear Security In Moroccan Territory After The Creation Of The New Moroccan Agency Of Nuclear And Radiological Safety And Security: Opportunities And Challenges, Amal Touarsi, Amina Kharchaf

International Journal of Nuclear Security

Nowadays, a security regime for protecting nuclear and radiological material—providing an intelligent national regulatory institution and establishing national security laws—is necessary in order for a state to ensure security of nuclear and radiological materials used within its borders.

This paper focuses on discussing the opportunities and challenges facing the future of nuclear security after the creation of the new Moroccan Agency of Nuclear and Radiological Safety and Security.

Determination Of Critical Experiment Correlations Via The Monte Carlo Sampling Technique, William Jay Marshall

Doctoral Dissertations

Critical benchmark experiments are the foundation of validation of the computational codes used in criticality safety analyses because they provide a basis for comparison between the calculated results and the physical world. These experiments are often performed in series varying a limited number of parameters to isolate the effect of the independent parameter. The use of common materials, geometries, machines, procedures, detectors, or other shared features can create correlations among the resulting experiments. Most validation techniques used in criticality safety practice do not treat these correlations explicitly, and the effect of this is unclear as the correlations themselves are not …

Double Differential Neutron Yields Produced By Proton, Helium, And Iron Interactions In Thick Aluminum Targets, Natalie Ann Mcgirl

Doctoral Dissertations

Recent calculations of galactic cosmic ray (GCR) transport in enclosed, shielded space environments indicate that a minimum dose equivalent is achieved with aluminum shielding thicknesses near 20 g/cm² [grams per centimeter squared]. Increases in the absorbed dose and dose equivalent with shielding thicknesses above 20 g/cm² are believed to be caused by the production of light ions and neutrons in the thick shielding. However, uncertainties surround these calculations due to limited cross section and yield data for high-energy projectiles incident on thick targets. Thick-target neutron yields are particularly valuable measurements since they are produced over a wide range …

Novel Fission Track Detection For Identification And Characterization Of Special Nuclear Materials, Jonathan Allen Gill

Doctoral Dissertations

Fission track detection and analysis is used primarily in nuclear safeguards to identify special nuclear material. Identification of isotopic ratios is a crucial step in understanding the intended use of nuclear material and the nature of the materials production cycle. Unfortunately, this methodology uses etchable track detectors that require significant expertise and intensive labor to process.

This study developed a novel method using lithium fluoride (LiF) as a fluorescing nuclear track detector to conduct fission track analysis for isotopic prediction of uranium enrichment. Individual latent tracks produced by fission products were observed in LiF for the first time. These tracks …

Nestle To Origami Coupling: A Nuclear Non-Proliferation Tool For Lwr Fuel Assembly Isotope Analysis, Margaret Alva Kurtts

Doctoral Dissertations

NESTLE to ORIGAMI coupling is a versatile nuclear modeling tool that allows researchers to directly observe the impact of operator induced changes on LWR assembly isotope production. The paper presents an experimental method by which to test the ability of an operator to manipulate the core neutron spectrum in order to produce higher quality plutonium for weapons use. The paper presents two plutonium production scenarios and evaluates their feasibility based on potential for detection and production capacity. Reactor modeling of a VVER-1000 uses NESTLE core simulation software. NESTLE outputs burnup and relative power information for all nodes in the core. …

Determining 235u Enrichment Using A Dual-Energy Approach For Delayed Neutron Measurements, Angela Lynn Lousteau

Doctoral Dissertations

Bulk uranium items are often measured using active neutron interrogation systems to take advantage of the relatively high penetrability of neutrons, providing the ability to quickly and accurately measure uranium masses in large, dense configurations. Active techniques employ an external neutron source to induce fission in the uranium and subsequently measure emitted prompt fission or delayed neutrons. Unfortunately, the emitted neutrons from ²³⁵U [uranium-235] and ²³⁸U [uranium-238] are, for all practical purposes, indistinguishable; therefore, commonly used systems such as the Active Well Coincidence Counter, the ²⁵²Cf [californium-252] Shuffler, and other systems based on measurement of prompt or …

Methodology For An Advanced Risk Assessment Of Crud Induced Power Shift Using Coupled Multi-Physics Simulations And A Monte Carlo Scenario Analysis Of The Potential Financial Benefits, Travis Louis Lange

Doctoral Dissertations

Beginning in the 1970's, power uprates in nuclear power plants began to cause an operational problem called Crud Induced Power Shift (CIPS). Over decades, a method has been developed and refined that has allowed industry to effectively avoid CIPS. However, increasingly challenging economic environments have caused power plants to utilize more aggressive core designs. The problem of CIPS still looms over many reactors as a potential hazard requiring conservative measures. CIPS is due to complex physical and chemical interactions. Current industry methods use multiple single-physics simulations in their analyses. However, improved 3D multi-physics models of CIPS can provide a better …

Modeling Of Dislocation Channel Formation And Evolution In Irradiated Metals, Peter James Doyle

Masters Theses

Defect-free dislocation channel formation has been reported to promote plastic instability during tensile testing via localized plastic flow, leading to a distinct loss of ductility and strain hardening in many low-temperature irradiated materials. In order to study the underlying mechanisms governing dislocation channel width and formation, the channel formation process is modeled via a simple stochastic dislocation-jog process dependent upon grain size, defect cluster density, and defect size. Dislocations traverse a field of defect clusters and jog stochastically upon defect interaction, forming channels of low defect-density. Based upon prior molecular dynamics (MD) simulations and in-situ experimental transmission electron microscopy (TEM) …

Positron Emission Particle Tracking Software Maturation Project, Eric Michael Moore

Masters Theses

Positron Emission Particle Tracking (PEPT) software at the University of Tennessee (MultiPEPT) has demonstrated promising performance in multiple measurement domains. In order to contribute to its further development, a full codebase audit and three focused performance assessments were undertaken. Several improvements were made to the codebase as a result of the audit. The assessments demonstrated a linear axial detector- MultiPEPT response, the effect of mesh size variation, and the effect of temporal overlap variation. A number of best practices are compiled for effective use of MultiPEPT.

Improvements To Nestle: Cross Section Interpolation And N-Group Extension, William Matthews Kirkland

Masters Theses

The NESTLE program is a few-group neutron diffusion reactor core simulator code utilizing the nodal expansion method (NEM). This thesis presents two improvements made to NESTLE regarding cross-section interpolation and multigroup capability.

To quickly and accurately obtain cross sections from lattice physics input data, a new cross section interpolation routine was developed utilizing multidimensional radial basis function interpolation, also known as thin plate spline interpolation. Testing showed that, for existing NESTLE lattice physics input, accuracy was retained but not improved and processing time was longer. However, the new interpolation routine was shown allow much greater exibility in the case matrix …

The Development Of Cesium Calcium Bromo-Iodide Scintillator For X-Ray And Gamma Ray Detection, Matthew Starr Loyd

Masters Theses

CsCaI₃:Eu [cesium calcium iodide doped with europium] is a promising scintillator material that can be grown from the melt, but undergoes a tetragonal to orthorhombic phase transition upon cooling at 255 °C [degrees Celsius], causing twinning and cloudiness. The purpose of this work is to suppress this solid to solid phase transition in the CsCaI₃:Eu scintillator, which has a light yield of ~40000 ph/Mev and energy resolution at 662keV of ~4%, by halide replacement to form the compound CsCaBr_xI_3-x:Eu [cesium calcium bromo-iodide doped with europium]. Crystals 8 cm³ [cubic centimeters] in …

Solar System Battery Backups For Reactor Coolant Pumps During Electricity Outages Resulting From Natural Disasters, Md. Shamsul Huda Sohel

International Journal of Nuclear Security

In a nuclear power plant, its coolant system is major safety equipment. Coolant system failure causes several accidents in nuclear history. There are so many causes for coolant system failure. One of them is lack of electric power for coolant pumps. In typically NPP there is backup system for power redundancy. In this article, focus on reactor coolant system and its backup power when main grid lines failure. Here discuss about solar backup power for batteries and increases a safety lines for reactor coolant pumps. So, our main goal is providing a battery backup from reliable natural source and ensuring …

The Inverse Kinetics Method And Its Application To The Annular Core Research Reactor, Thomas A. Ball

Nuclear Engineering ETDs

The inverse kinetics method, is a method to calculate a reactor’s reactivity profile from its power profile. In this thesis, the reactivity profile corresponding to pulse operations of the Annular Core Research Reactor (ACRR) was sought. Of specific interest was the shutdown reactivity of the reactor following the pulse. This required accounting for delayed beryllium photoneutrons that are present in the ACRR in addition to U-235 delayed neutron precursors. The power profiles of the pulses were experimentally measured using a diamond photoconductive detector (PCD). Using the inverse kinetics equation, a computer code was written to numerically calculate the reactivity corresponding …

Evaluation Of Energy Released From Nuclear Criticality Excursions In Process Solutions, Corey Michael Skinner

Nuclear Engineering ETDs

Typically, the staff of a nonreactor nuclear facility or a processing facility involving nuclear material are not expected to have a strong technical background in nuclear criticality physics, as that is not the purpose of these sites, yet handle material with the potential to undergo a criticality excursion. Such excursions have occurred 22 times in the past, 21 of which involved an aqueous solution material. Therefore, it would be useful to have a general model capable of providing a quick estimation of the consequences of a criticality excursion in a processing plant. To this end, correlations developed utilizing experimental data …

Gamma-Radiation Induced Corrosion Of Alloy 800, Mojtaba Momeni

Electronic Thesis and Dissertation Repository

This thesis presents a newly developed mechanism and predictive model for the corrosion of Alloy 800. The Fe-Cr-Ni Alloy (Incoloy 800) is mainly used for steam generator (SG) tubing in CANDU and PWR reactors and is a candidate material for the proposed Canadian Supercritical Water Reactor (SCWR) in which it will be exposed to extreme conditions of high radiation flux and large temperature gradients. The influence of gamma radiation and water chemistry conditions on the corrosion behaviour of Alloy 800 are studied in this work. Ionizing radiation creates reducing (•e_aq^–, •H, •O₂^-) and oxidizing …

Time-Of-Flight And Energy Loss Analysis On The Unm Fission Fragment Spectrometer, Shelby Fellows

Nuclear Engineering ETDs

The University of New Mexico spectrometer experimental work has been used to provide an event-by-event fission product measurement to aid in filling in the gaps in existing fission product yield data, as part of the Los Alamos National Lab Spectrometer for Ion Detection in Fission Research project (SPIDER) collaboration. This thesis examines the time-of-flight (TOF) component of the spectrometer towards improving the resolution of the system. Different thicknesses of TOF conversion foils were examined with alpha particles and fission fragments: 20, 55, and 100 µg/cm² carbon foils. For the thinnest carbon foil studied, a timing resolution of 160 ps …

Asymptotic Neutronic Solutions For Fast Burst Reactor Design, Edward L. Hobbs

Nuclear Engineering ETDs

Deterministic numerical methodologies for solving time-eigenvalue problems are valuable in characterizing the inherent rapid transient neutron behavior of a Fast Burst Reactor (FBR). New nonlinear solution techniques used to solve eigenvalue problems show great promise in modeling the neutronics of reactors. This research utilizes nonlinear solution techniques to solve for the dominant time-eigenvalue associated with the asymptotic (exponential) solution to the neutron diffusion and even-parity form of the neutron transport equation, and lays the foundation for coupling with other physics phenomena associated with FBRs.

High security costs and proliferation risks associated with Highly Enriched Uranium (HEU) fueled FBRs are the …

Nuclear Fusion As A Primary Energy Production Method, Joshua Eiswirth

Missouri S&T’s Peer to Peer

In this paper, the possibility of using nuclear fusion as a primary energy producer will be analyzed. A brief overview of nuclear fusion is given as well as the drawbacks of nuclear fusion today. The human species, need to find a more abundant and renewable means to produce energy, because the non-renewable resources relied on today will be completely used up in as little a 100 years. Nuclear fusion, if perfected, offers a reliable and extremely abundant energy source. With commercial nuclear fusion plants more energy would be available than ever before. While no efficient fusion reactor design exists today, …

Sensitivity Analysis For Best-Estimate Thermal Models Of Vertical Dry Cask Storage Systems, Remy R. Devoe, Kevin R. Robb, Steven Skutnik

Faculty Publications and Other Works -- Nuclear Engineering

Loading requirements for dry cask storage of spent nuclear fuel are driven primarily by decay heat capacity limitations, which themselves are determined through recommended limits on peak cladding temperature within the cask. This study examines the relative sensitivity of peak material temperatures within the cask to parameters that influence both the stored fuel residual decay heat as well as heat removal mechanisms. These parameters include the detailed reactor operating history parameters (e.g., soluble boron concentrations and the presence of burnable poisons) as well as factors that influence heat removal, including non-dominant processes (such as conduction from the fuel basket to …

Temporal Resolution Of Cell Death Signaling Events Induced By Cold Atmospheric Plasma And Electroporation In Human Cancer Cells, Danielle M. Krug, Prasoon K. Diwakar, Ahmed Hassanein

The Summer Undergraduate Research Fellowship (SURF) Symposium

Cancer treatment resistance and their invasive and expensive nature is propelling research towards developing alternate approaches to eradicate cancer in patients. Non-thermal, i.e., cold atmospheric plasma (CAP) and electroporation (EP) applied to the surface of cancerous tissue are new methods that are minimally invasive, safe, and selective. These approaches, both independently and synergistically, have been shown to deplete cancer cell populations, but the signaling mechanisms of death and their timelines of action are still widely unknown. To better understand the timeframe of signaling events occurring upon treatment, human cancer cell lines were treated with CAP, EP, and combined CAP with …

Comparison Of Pm-Hip To Cast Alloy 625 For Nuclear Applications, Alexander L. Bullens, Keyou Mao, Janelle P. Wharry, Esteban Bautista

The Summer Undergraduate Research Fellowship (SURF) Symposium

PM-HIP, or Powder Metallurgy and Hot Isostatic Pressing, metals have been a low cost alternative to forged and cast structural metals within various industries. The nuclear industry has recently developed interest in PM-HIP alloys, but further research needs to be done to quantify their mechanical properties and characterize the microstructure. Specifically, we must understand the mechanical and microstructural evolution of PM-HIP materials after long-term operation at the elevated temperatures that PM-HIP components will experience in service. We focus on Ni-base alloy Inconel 625, and compare the PM-HIP version to the cast version. Our methodology consists of annealing samples to various …

Irradiation-Induced Nanocluster Evolution, Didier Ishimwe, Matthew J. Swenson, Janelle P. Wharry

The Summer Undergraduate Research Fellowship (SURF) Symposium

Oxide dispersion strengthened steel (ODS) and commercial ferritic-martensitic (F-M) alloys are widely accepted candidate structural materials for designing advanced nuclear reactors. Nanoclusters embedded in the steel matrix are key microstructural features of both alloy types. Irradiation from nuclear fusion and fission affects the morphology of these nanoparticles, altering the performance of the alloys and potentially decreasing their usable lifetime. Thus, it is important to understand the effect of irradiation on these nanoparticles in order to predict long-term nuclear reactor performance. It was found that the evolution of nanoclusters in each material is different depending on the experimental irradiation parameters. The …

Numerical Simulations Of Transcritical Natural Convection, Ruiwen Wei, Carlo Scalo, Mario Tindaro Migliorino, Kukjin Kim, Jean-Pierre Hickey

The Summer Undergraduate Research Fellowship (SURF) Symposium

In modern engineering applications, system overheating is a key issue that needs to be solved with efficient and reliable cooling technologies. Among the possible mechanisms that these are based on, natural convection cooling is one of the most frequently employed, with applications ranging from cooling of computer micro-components to large nuclear reactors. While many studies have been performed on natural convection employing supercritical or subcritical fluids, little attention has been given to fluids in their transcritical regime. The latter has the potential to yield high performances while avoiding detrimental effects of two-phase systems (e.g. cavitation). In the present study, 2D …

Verification Of Tfit Code Numerical Method For Flow Excursion Simulation, Patrick S. Foster, Subash Sharma, Martin L. Bertodano

The Summer Undergraduate Research Fellowship (SURF) Symposium

This research is aimed towards accurately modeling and predicting the onset of the two-phase flow excursion instability using the code TFIT (Two Fluid Interfacial Temperature). In order to do this we first had to show that the numerical diffusion of the code’s finite difference equations could be reduced to an insignificant level by decreasing the mesh size.

Understanding and being able to accurately model flow excursion can help us understand how to prevent the potential negative effects of this instability. We are using a two-fluid model with physics-based closure relations. The results will be validated against the experimental data available …

Investigating Tantalum As A Plasma-Facing Component For Nuclear Fusion Reactors, Arvind Sundaram, Jitendra K. Tripathi, Theodore J. Novakowski, Ahmed Hassanein Ph. D.

The Summer Undergraduate Research Fellowship (SURF) Symposium

Nuclear fusion is a potential source for producing unlimited environment-friendly energy. Tungsten (W) is selected as the primary candidate material for plasma facing component in nuclear fusion reactors due to its high melting temperature (3695 K), low sputtering erosion yield and strong mechanical properties. However, recent investigations on W have confirmed that it undergoes severe surface morphology changes during low energy He plasma and/or ion irradiation similar to a harsh fusion environment. Additionally, our previous studies indicate that tantalum (Ta) may show better resistance to the harsh radiation environment and is therefore worthy of investigation. Hydrogen retention properties, specifically deuterium …

Development Of An Unmanned Aerial System For Radiation Mapping In Nuclear Facilities, Jackson Ball, Guangying Jiang, Robert Bean

The Summer Undergraduate Research Fellowship (SURF) Symposium

Efficiently planning a decontamination and decommissioning (D&D) operation at a nuclear facility requires detailed information on the conditions present. In the wake of a disaster, or just years of abandonment, a facility’s layout may have dramatically changed, making previous facility drawings unreliable, and radioactive particles may have been spread over the site, contaminating equipment and structures. Rather than tasking workers with mapping and characterizing the contamination, which can take days or weeks and poses a health and safety risk to the workers, mapping the site and locating contamination can be done remotely by an unmanned aerial vehicle (UAV), which would …

Improvements To The Predictive Capability Of Fcm Fuel Performance Modeling, Daniel Philip Schappel

Doctoral Dissertations

A proposed fuel type for improved accident performance in LWRs (Light Water Reactors) involves TRISO (Tristructural-Isotropic) particles embedded in a NITE (Nano Infiltrated Eutectic) silicon carbide matrix. TRISO fuel particles contain a spherical fuel kernel of about 500 to in excess of 800 microns in diameter. The kernel and buffer layer are then coated with three isotropic layers consisting of a dense inner pyrolytic carbon (IPyC), a silicon carbide (SiC) layer, and an outer pyrolytic carbon (OPyC) layer. These layers are about 40 microns thick. The TRISO particle packing fraction in the NITE-SiC matrix is expected to be about 40 …

Intrusion Detection Of A Simulated Scada System Using A Data-Driven Modeling Approach, Brien Alen Jeffries

Doctoral Dissertations

Supervisory Control and Data Acquisition (SCADA) are large, geographically distributed systems that regulate help processes in industries such as nuclear power, transportation or manufacturing. SCADA is a combination of physical, sensing, and communications equipment that is used for monitoring, control and telemetry acquisition actions. Because SCADA often control the distribution of vital resources such as electricity and water, there is a need to protect these cyber-physical systems from those with possible malicious intent. To this end, an Intrusion Detection System (IDS) is utilized to monitor telemetry sources in order to detect unwanted activities and maintain overall system integrity.

This dissertation …