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2025

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Full-Text Articles in Nuclear Engineering

Atomic Offsets: Nuclear Policy Shifts For Arctic States In The Wake Of Moscow’S Special Military Operation, Molly Wise, Lillian Hussong Aug 2025

Atomic Offsets: Nuclear Policy Shifts For Arctic States In The Wake Of Moscow’S Special Military Operation, Molly Wise, Lillian Hussong

Space and Defense

This article examines how Russia’s 2022 invasion of Ukraine has intensified nuclear reliance among Arctic states. Applying a new framework of “conventional-nuclear vulnerability,” it analyzes the nuclear policy shifts of Sweden, Finland, and Russia. The findings show that Finland and Sweden pursued NATO membership to secure nuclear guarantees, while Russia adopted riskier nuclear signaling and lowered thresholds for nuclear use. These developments highlight the growing centrality of nuclear deterrence in Arctic security, underscoring the challenges for U.S. and NATO policymakers in balancing assurance and deterrence in a volatile regional environment.

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Russian Strategic Culture And Deterrence In The Arctic, Lana Obradovic, Bethany Vailliant Aug 2025

Russian Strategic Culture And Deterrence In The Arctic, Lana Obradovic, Bethany Vailliant

Space and Defense

This study analyzes Russia’s evolving strategic culture to assess its implications for deterrence in the Arctic. It argues that Western deterrence frameworks insufficiently account for Russia’s integration of military, economic, informational, and political tools into a holistic strategy. Rooted in a siege mentality and aspirations for great power status, Russia perceives the Arctic as central to its security, economic modernization, and geopolitical influence. By situating Arctic policy within this cultural framework, the analysis highlights the need for U.S. and NATO practitioners to reassess assumptions and develop more culturally attuned deterrence strategies.

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Table Of Contents Vol. 16 No. 1, Editors Space And Defense Aug 2025

Table Of Contents Vol. 16 No. 1, Editors Space And Defense

Space and Defense

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Front Matter, Editors Space And Defense Aug 2025

Front Matter, Editors Space And Defense

Space and Defense

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Space And Defense Vol. 16 No. 1 Summer 2025 Special Issue On Arctic Security (Whole Issue), Editors Space And Defense Aug 2025

Space And Defense Vol. 16 No. 1 Summer 2025 Special Issue On Arctic Security (Whole Issue), Editors Space And Defense

Space and Defense

Articles that cover issues on Artic Security.

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Ai-Driven Uncertainty Quantification & Multi-Physics Approach To Evaluate Cladding Materials In A Microreactor, Alexander Foutch, Kazuma Kobayashi, Ayodeji Babatunde Alajo, Dinesh Kumar, Syed Bahauddin Alam Aug 2025

Ai-Driven Uncertainty Quantification & Multi-Physics Approach To Evaluate Cladding Materials In A Microreactor, Alexander Foutch, Kazuma Kobayashi, Ayodeji Babatunde Alajo, Dinesh Kumar, Syed Bahauddin Alam

Nuclear Engineering and Radiation Science Faculty Research & Creative Works

The pursuit of enhanced nuclear safety has spurred the development of accident-tolerant cladding (ATC) materials for light water reactors (LWRs). This study investigates the potential of repurposing these ATCs in advanced reactor designs, aiming to expedite material development and reduce costs. The research employs a multi-physics approach, encompassing neutronics, heat transfer, thermodynamics, and structural mechanics, to evaluate four candidate materials (Haynes 230, Zircaloy-4, FeCrAl, and SiC–SiC) within the context of a high-temperature, sodium-cooled microreactor, exemplified by the Kilopower design. While neutronic simulations revealed negligible power profile variations among the materials, finite element analyses highlighted the superior thermal stability of SiC–SiC …


Isotope Production Modeling In Sodium-Cooled Fast Reactors, Aaron W. Burkhardt Jun 2025

Isotope Production Modeling In Sodium-Cooled Fast Reactors, Aaron W. Burkhardt

Theses and Dissertations

The accurate prediction of isotopic compositions in Sodium-Cooled Fast Reactors (SFRs) is essential for nuclear forensic analyses and international nuclear treaty monitoring, particularly with the increased global deployment of Generation-IV reactors. This research developed and validated a detailed computational model tailored specifically to the Prototype Fast Breeder Reactor (PFBR), employing advanced Monte Carlo neutron transport methods, sophisticated burnup modeling, and variance reduction techniques. Validation against empirical data from the Experimental Breeder Reactor-II confirmed the model’s accuracy, producing a comprehensive database of isotopic compositions across 301 assembly locations and 580 isotopes through the reactor’s initial operation and equilibrium cycle. The model …


Constraining Nuclear Data Uncertainty Requirements For The 19F(A, N)22Na Reaction For Non-Proliferation Applications, Tyler R. M. Smith Jun 2025

Constraining Nuclear Data Uncertainty Requirements For The 19F(A, N)22Na Reaction For Non-Proliferation Applications, Tyler R. M. Smith

Theses and Dissertations

This thesis explores the requirements on nuclear data uncertainties needed for the use of the 19F(α, n)22Na reaction for nuclear non-proliferation applications. An overview of how neutrons are produced from alpha decays in a UF6 medium is discussed. Calculation demonstrate the role nuclear data uncertainties effect the neutron yield and energy spectra as a function of enrichment.


Nuclear Energy: The Key To Sustainable Power For Ai And Emerging Technologies, Joshua Luke Ponsell, James Zurawski, Eli Musgrave, Johnny Demont, Eduardo B. Farfan Apr 2025

Nuclear Energy: The Key To Sustainable Power For Ai And Emerging Technologies, Joshua Luke Ponsell, James Zurawski, Eli Musgrave, Johnny Demont, Eduardo B. Farfan

Symposium of Student Scholars

Skeptics question whether Artificial Intelligence (AI) can be powered sustainably. Nuclear may just be the best option. AI is transforming various spaces, from cybersecurity to accessibility, by enhancing the detection and prevention of fraud and phishing attacks to improving real-time services like subtitle generation, and supporting language translation. AI's impact also extends to applications like handwriting and speech recognition, streamlining processes and increasing accessibility for individuals with disabilities. As AI becomes more integrated into everyday life, the increasing demand for its computational power raises concerns about energy consumption. By researching datacenter power demands empirically and comparing nuclear options as opposed …


Developing Modular Radiological Containment For The Naval Nuclear Lab, Markus Baur, Eric Franklin, Cameron Ashley, Joshua P. Schlegel Apr 2025

Developing Modular Radiological Containment For The Naval Nuclear Lab, Markus Baur, Eric Franklin, Cameron Ashley, Joshua P. Schlegel

Miners Solving for Tomorrow Research Conference

No abstract provided.


Design And Characterization Of Radiation-Hardened Gaas Hbt-Based Optical Transceivers, Collin Burt Apr 2025

Design And Characterization Of Radiation-Hardened Gaas Hbt-Based Optical Transceivers, Collin Burt

Electrical and Computer Engineering ETDs

Optical transceivers are desirable for their galvanic isolation and natural immunity to electromagnetic interference compared with direct electrical connections. This is true in normal operating environments as well as radiation environments. This work realizes and characterizes GaAs HBT-based optical transceivers across temperature and a range of radiation environments including high dose rate, total ionizing dose, neutron, and heavy ion. The transceiver designs are discussed and specific environmental design considerations are highlighted. Final results for each environment are provided and compared with existing transceivers.


Hybrid Machine Learning And Comparison Error Minimization For Frequency Domain-Based Rapid State Estimation In Structures Subjected To High-Rate Boundary Change, James Scheppegrell Apr 2025

Hybrid Machine Learning And Comparison Error Minimization For Frequency Domain-Based Rapid State Estimation In Structures Subjected To High-Rate Boundary Change, James Scheppegrell

Theses and Dissertations

Dynamic forces and evolving structural boundary conditions pose challenges for various structural systems such as aircraft, orbital infrastructure, and energy harvesting devices. The design, evaluation, and functionality, of such systems can be aided through the collection and analysis of data. However, real-time decision-making for systems experiencing high-rate changes can pose unique challenges, if assessments are to be made accurately and rapidly enough to be relevant. In cases where the systems are well-defined and thoroughly understood, monitoring the frequency response can be instrumental in determining the state of structures subjected to high-rate structural boundary condition changes. This study focuses on investigating …


Assessing The Feasibility Of Transportable Nuclear Reactors: A Radiological Risk Case Study, Robert John Demuth Apr 2025

Assessing The Feasibility Of Transportable Nuclear Reactors: A Radiological Risk Case Study, Robert John Demuth

Theses and Dissertations

The feasibility of a truly transportable nuclear reactor presents significant radiological challenges that must be addressed to ensure compliance with regulatory limits and operational safety. This study evaluates the radiological constraints associated with the transportability of the Transportable Helium-cooled One-megawatt Reactor (THOR), focusing on neutron activation, shielding performance, and external radiation exposure. Using advanced radiation transport and activation modeling within the SCALE framework, a comprehensive analysis was conducted to quantify dose rates during operation, post-shutdown, and transport. A key aspect of this work involved assessing activation products in core materials, auxiliary components, and surrounding environments to determine their contribution to …


The Effects Of Snow Cover On The Dynamic Pressure Of Nuclear Detonation Blast Waves, Adam Card, Andrew W. Decker Apr 2025

The Effects Of Snow Cover On The Dynamic Pressure Of Nuclear Detonation Blast Waves, Adam Card, Andrew W. Decker

Faculty Publications

Blast pressure is the primary military targeting metric for nuclear weapons. Any local conditions that affect blast pressure have the potential for altering nuclear plans, both from defensive and offensive standpoints. Understanding the impact of snow to the blast wave, therefore, provides a benefit both to military planners and to warfighters on the ground, for any operation occurring in arctic environments. No existing data provides a quantitative description of how snow on the ground affects a nuclear detonation blast wave passing over it. Similar blast waves passing over dust have experimentally proven to enhance blast pressure in a localized region.1 …


Machine Learning For Reactor Power Monitoring With Limited Labeled Data, C. L. Stewart, B. L. Goldblum, R. G. Abbott, L. Appleby, Brett J. Borghetti, V. Hollingshead, J. H. Whetzel Apr 2025

Machine Learning For Reactor Power Monitoring With Limited Labeled Data, C. L. Stewart, B. L. Goldblum, R. G. Abbott, L. Appleby, Brett J. Borghetti, V. Hollingshead, J. H. Whetzel

Faculty Publications

Real-time reactor power monitoring is critical for a variety of nuclear applications, spanning safety, security, operations, and maintenance. While machine learning methods have shown promise in monitoring reactor power levels, there is limited research on their efficacy in label-starved environments. The goal of this work is to assess the feasibility of classifying nuclear reactor power level using multisource data in scenarios with limited labels. Data were collected using low-resolution multisensors at four nuclear reactor facilities: two large research reactors and two TRIGA reactors. Within each pair, one reactor dataset served as the source and the other as the target in …


Saudi Arabian Universities' Need For A Nuclear Security Educational Textbook: A Systematic Review, Faisal Bin Nasser Sarbaland, Takaaki Sakai Mar 2025

Saudi Arabian Universities' Need For A Nuclear Security Educational Textbook: A Systematic Review, Faisal Bin Nasser Sarbaland, Takaaki Sakai

International Journal of Nuclear Security

Nuclear security education is a critical element in ensuring the safe and responsible use of nuclear energy, particularly in countries like Saudi Arabia, where the demand for energy is increasing. This systematic review explores the current needs for nuclear security educational materials in Saudi Arabian universities, focusing on the development of a specialized textbook for this purpose. The review addresses the increasing global demand for nuclear security professionals and highlights the gaps in educational resources available in the Middle East, particularly in Saudi Arabia. Using a thematic analysis of existing educational programs and curricula from various international institutions, the paper …


Analysis Of Nuclear Security And Safety Integration Using Survey Responses And Pairwise Comparison Methods, Sheila V. Gbormittah, Theodore A. Thomas, Jason Timothy Harris Mar 2025

Analysis Of Nuclear Security And Safety Integration Using Survey Responses And Pairwise Comparison Methods, Sheila V. Gbormittah, Theodore A. Thomas, Jason Timothy Harris

International Journal of Nuclear Security

Integrating nuclear security and safety is important for implementing and sustaining nuclear technology because it promises improved and effective management. This integration is an ongoing effort to ensure that both work together with minimal conflicts. This research aimed to determine the preferred level at which nuclear security and nuclear safety integrate by using the pairwise comparison methods of decision-making. This methodology used survey responses from women nuclear professionals to identify the most-desired criteria at three levels: strategic, operational, and cultural. The strategic level includes actions that government officials and regulators can take. The operational level encompasses actions that deliver the …


Radiation Assessment And Distribution In Changing Atmospheric Structures And Turbulence (Radcast), Steven B. Hernandez Mar 2025

Radiation Assessment And Distribution In Changing Atmospheric Structures And Turbulence (Radcast), Steven B. Hernandez

Theses and Dissertations

The accessibility of materials and online information has made radiological dispersal devices (RDDs) a more probable threat than conventional nuclear weapons. This study analyzed five datasets from three test periods, using a correlation analysis between optical turbulence, aerosol concentration, and environmental parameters, and geometric mean diameter (GMD) calculations. The correlation analysis failed to yield meaningful insights, prompted a transition to the GMD analysis, which produced clearer results. Findings show GMD ranged from 38–41 nm, increasing at night and during neutral events as reduced vertical motion and boundary layer contraction correlated with optical turbulence. An alternative GMD dataset, calculated by the …


Measurements Of The Radioisotope Production Cross Section Of 193Ir(N,N')193mIr Between 0.5–9 Mev, Ronnie P. Rera Mar 2025

Measurements Of The Radioisotope Production Cross Section Of 193Ir(N,N')193mIr Between 0.5–9 Mev, Ronnie P. Rera

Theses and Dissertations

This thesis covers a measurements of the radioisotope production cross section of 193Ir(n,n′) 193mIr between 0.5–9 MeV is discussed. The experiment was performed at the University of Notre Dame St.ANA 5U accelerator laboratory. Experimental planning, data collection, analysis, results, and impacts are discussed.


Characterization Of The Neutron Spectrum Produced By A Pulsed Power Generator, Daniel S. Godlasky Mar 2025

Characterization Of The Neutron Spectrum Produced By A Pulsed Power Generator, Daniel S. Godlasky

Theses and Dissertations

Neutron time-of-flight, activation foils, and spectral unfolding software were used to characterize the energy and fluence of the neutron spectrum created by the Gamble II pulsed power generator. Gamble II is a pulsed power generator that delivers a 1 MV to 2.2 MV and 800 kA electrical pulse peaking at 50 ns. This electrical release creates deuterium ions in the diode that are accelerated to a neutron converter covered with a novel lithium fluoride or deuterated polyethylene to create primarily 7Li(d,n) or D(d,n) and 12C(d,n) nuclear reactions. In October 2024, two D(d,n) shots occurred, and in November 2024, …


Design, Simulation, And Characterization Of A Deuterated Plastic Scintillator For A Portable Neutron Spectrometer, Anders M. Kinney Ii Mar 2025

Design, Simulation, And Characterization Of A Deuterated Plastic Scintillator For A Portable Neutron Spectrometer, Anders M. Kinney Ii

Theses and Dissertations

This thesis examines the design, simulation, and experimental characterization of a novel deuterated plastic scintillator for portable neutron spectroscopy applications related to homeland security and nuclear non-proliferation. Using Monte Carlo N-Particle (MCNP) simulations and experimental tests with gamma-ray (137Cs) and neutron sources (AmBe, 252Cf), this research shows that deuterium substitution in scintillators significantly enhances pulse shape discrimination (PSD) and neutron energy spectrum unfolding capabilities. Although deuterated scintillators demonstrate reduced overall light output, their higher stopping power and increased ionization quenching lead to superior neutron event differentiation, particularly between (α, n) and spontaneous fission neutrons critical for detecting …


Effective Management Of Disused Sealed Radioactive Sources In Uganda, Susan Nalumansi Jan 2025

Effective Management Of Disused Sealed Radioactive Sources In Uganda, Susan Nalumansi

International Journal of Nuclear Security

Sealed radioactive sources are used in a wide range of applications in Uganda, such as medicine, agriculture, geology, industry, and other fields. After a given useful period, the sealed sources can no longer perform their intended purpose and are thus regarded as disused. However, depending on the activity of the source, the disused sources are highly active and can cause significant damage to human health and the environment when mismanaged. A regulatory body was established with the mandate to regulate peaceful applications of ionizing radiation in Uganda. Given the vulnerability of sealed sources at the end of their life cycle …


Development Of P-Type Cesium Iodide Thin Film For Radiation Detection By Rf-Magnetron Sputtering, Rhett Simon Tabbada Jan 2025

Development Of P-Type Cesium Iodide Thin Film For Radiation Detection By Rf-Magnetron Sputtering, Rhett Simon Tabbada

Chulalongkorn University Theses and Dissertations (Chula ETD)

Cesium iodide (CsI) is a wide-bandgap alkali halide semiconductor with strong potential for radiation detection and optoelectronic integration, though its intrinsic insulating nature limits charge transport. In this study, the effects of silicon (Si) doping on the structural, optical, electrical, and radiation-response capabilities as a semiconductor of CsI thin films were determined. The CsI thin films were deposited on n-Silicon (n-Si) (100) substrates using magnetron sputtering. In the optimization of sputtering conditions, three films with a thickness of 250 nm were fabricated with varying sputtering power for Si: 0W, 5W, and 10W, while keeping the sputtering power for CsI constant …


การพัฒนาฟิล์มบางซีเซียมไอโอไดด์ชนิดเอ็นเพื่อการวัดรังสีด้วยเทคนิคสปัตเตอริง, กฤตยชญ์ คูณคณะ Jan 2025

การพัฒนาฟิล์มบางซีเซียมไอโอไดด์ชนิดเอ็นเพื่อการวัดรังสีด้วยเทคนิคสปัตเตอริง, กฤตยชญ์ คูณคณะ

Chulalongkorn University Theses and Dissertations (Chula ETD)

ผลึกซีเซียมไอโอไดด์เป็นหนึ่งในวัสดุอัลคาไลฮาไลด์ที่มีประสิทธิภาพมากในการตรวจจับรังสี แม้ว่าคุณสมบัติความเป็นฉนวนโดยธรรมชาติของมันจะจำกัดการถ่ายเทประจุ ในการศึกษานี้ ฟิล์มบางซีเซียมไอโดไดด์ถูกเจือด้วยทองแดงบนฐานรองซิลิกอนโดยใช้เทคนิคสปัตเตอริงซีเซียมไอโอไดด์สำหรับกำลังการปลูกที่ 30 วัตต์ ทองแดงสำหรับกำลังการปลูกที่ 50 และ 80 วัตต์ สมบัติเชิงโครงสร้าง คุณสมบัติทางแสง คุณสมบัติทางไฟฟ้า และการตอบสนองต่อรังสีของฟิล์มบางเหล่านี้ได้รับการตรวจสอบอย่างครอบคลุม ผลการวิเคราะห์สมบัติทางโครงสร้างผลึกโดยเทคนิค GIXRD พบว่า ฟิล์มบางที่สัเคราะห์ได้นี้เป็นโครงสร้างผลึกของซีเซียมไอโอไดด์ที่เจือด้วยทองแดง ซึ่งฟิล์มซีเซียมไอโอไดด์นี้มีค่าแลตทิซของหน่วยผลึกแบบบีบอัดขนาด 4.4102 Å (80 วัตต์) และขนาด 4.4516 Å (50 วัตต์) และค่าความเครียดลดลงจาก 3.29% เป็น 2.38% การวิเคราะห์เชิงแสงโดยใช้วิธี Tauc–Kubelka–Munk ระบุช่องแถบพลังานของซีเซียมไอโอไดด์พลังงานที่ 3.25 อิเล็กตรอนโวลต์ การศึกษาลักษณะทางไฟฟ้า ได้ผลว่า ฟิล์มซีเซียมไอโอไดด์ที่เจือด้วยทองแดง มีความหนาแน่นของพาหะคือ -1.822×1012 cm-3 ความคล่องตัวคือ 2.436×107 cm² V-1s-1 และสภาพต้านทานไฟฟ้าคือ 0.1407 Ω·cm และเมื่อนำฟิล์มซีเซียมไอโอไดด์นี้พัฒนาต่อให้เป็นอุปกรณ์ไดโอดรอยต่อพีเอ็นที่มีชั้นเคลือบทองคำชั้นบนสุดของชิ้นงาน Au/p-CsI/n-CsI:Cu/n-Si มาทดสอบการตอบสนองทางรังสีต่าง ๆ คือ แสงสว่าง รังสีแกมมา และอนุภาคแอลฟา ที่สภาวะแวดล้อมแสงต่างกัน ซึ่งผลการตอบสนองรังสีเหล่านี้เบื้องต้นได้ผลสัญญาณวัดในฟังก์ชันเวลาที่แสดงความแตกต่างกันได้ค่อนข้างชัดเจน และผลการทดลองนี้สามารถเป็นแนวทางในการพัฒนาโครงสร้างวัสดุซีเซียมไอโอไดด์ที่เจือทองแดงนี้ต่อไปเป็นหัววัดรังสีแอลฟาและรังสีชนิดอื่น ๆ ให้มีประสิทธิภาพดีขึ้นได้ในอนาคตต่อไป


การผลิตละอองลอยที่มีลูกหลานเรดอนเกาะติดสำหรับการประเมินปริมาณรังสียังผลที่ปอด, รุ่งโรจน์ สกุลเนรมิตร์ Jan 2025

การผลิตละอองลอยที่มีลูกหลานเรดอนเกาะติดสำหรับการประเมินปริมาณรังสียังผลที่ปอด, รุ่งโรจน์ สกุลเนรมิตร์

Chulalongkorn University Theses and Dissertations (Chula ETD)

งานวิจัยนี้มีวัตถุประสงค์เพื่อพัฒนาระบบและกระบวนการผลิตละอองลอยกัมมันตรังสีที่มีนิวไคลด์ลูกหลานเรดอนเกาะติดภายใต้สภาวะควบคุม เพื่อจำลองลักษณะทางกายภาพของอนุภาคในสิ่งแวดล้อมจริง และประเมินปริมาณรังสียังผลที่ปอดได้รับ โดยมุ่งเน้นการศึกษาในช่วงขนาดอนุภาค 10 ถึง 150 นาโนเมตร ซึ่งเป็นช่วงขนาดวิกฤตที่มีโอกาสตกสะสมในถุงลมปอดและส่งผลกระทบทางชีวภาพสูงสุด การศึกษาดำเนินการโดยใช้สารละลายตั้งต้น 3 ชนิด ได้แก่ โซเดียมคลอไรด์, กลูโคส และโพแทสเซียมเปอร์แมงกาเนต ที่ระดับ ความเข้มข้นแปรผันตั้งแต่ 1,000 ถึง 10,000 ppm ร่วมกับการศึกษาอิทธิพลของปัจจัยสิ่งแวดล้อม ได้แก่ อุณหภูมิ (25 และ 35 องศาเซลเซียส) และความชื้นสัมพัทธ์...


Investigation Of Radiation Absorption Behavior Of Banana Leaves And Onion: A Cost-Effective Way Of Radiation Protection, Arpita Datta, Alpana Goel, Shreya Singh Jan 2025

Investigation Of Radiation Absorption Behavior Of Banana Leaves And Onion: A Cost-Effective Way Of Radiation Protection, Arpita Datta, Alpana Goel, Shreya Singh

International Journal of Nuclear Security

Shielding of nuclear radiation is an important component of radiation safety aiming to reduce the exposure of ionizing radiation to radiation workers. In the present work, beta and gamma radiation absorption properties of various environmentally friendly natural materials such as onion, banana leaf, and banana stem were investigated with a view to understand their radiation shielding capability. Pure beta source 90Sr–90Y and gamma sources such as 241Am, 137Cs and 60Co were used to study the attenuation of beta and gamma radiation using these natural materials. Intensity of the emitted radiation was measured by placing …


Design And Development Of A System That Characterizes Highintensity Gamma Fields From Rinsc Nuclear Fuel, Michael Peters Jan 2025

Design And Development Of A System That Characterizes Highintensity Gamma Fields From Rinsc Nuclear Fuel, Michael Peters

Open Access Master's Theses

Nuclear energy is a form of energy that utilizes the fissile nature of uranium, or other fissionable elements, to produce heat. In a uranium core, this reaction consists of a thermalized neutron being absorbed by the uranium nucleus, splitting the atom, and thus creating two subsequent fission products, along with the release of three neutrons, heat, and gamma radiation. These fission products are randomly generated elements, commonly in the form of isotopes of iodine, cesium, strontium, xenon, and barium. Although the type of fission products is known, much is still unknown about the nature of these isotopes, such as their …


Input Independent Observers For Bilinear Systems Using Convex Optimization, M. Aminul Haq, W. Steven Gray Jan 2025

Input Independent Observers For Bilinear Systems Using Convex Optimization, M. Aminul Haq, W. Steven Gray

Electrical & Computer Engineering Faculty Publications

An asymptotic state variable observer is proposed for a continuous-time bilinear dynamical system with the distinguishing feature that the error dynamics are globally asymptotically stable and independent of the applied input. Only the speed of convergence of the error dynamics may be input dependent. The approach is to apply classical Lyapunov stability theory using a convex optimization algorithm and linear matrix inequality (LMI) tools to in effect isolate the stability property of the error dynamics from the input. The LMIs are used to turn the nonconvex problem into a convex problem. The method is demonstrated on an induction motor drive.


Multiphysics Modeling Of Material Response To High-Intensity X-Ray And Laser Pulses: Heating, Ablation, And Plasma Expansion, Youssef Abouhussien Jan 2025

Multiphysics Modeling Of Material Response To High-Intensity X-Ray And Laser Pulses: Heating, Ablation, And Plasma Expansion, Youssef Abouhussien

Theses and Dissertations

This dissertation presents a computational framework to investigate material response under high-intensity X-ray fluxes produced by an exo-atmospheric nuclear detonation and laser-material irradiations, with a focus on heating, ablation, and plasma expansion phenomena relevant to satellite vulnerability and high-energy-density environments. A hybrid Monte Carlo and Two-Temperature Model (MC-TTM) was developed to simulate X-ray and laser energy deposition and thermal relaxation in metals and semiconductors across a range of X-ray and laser pulse durations from femtoseconds to nanoseconds. Results demonstrate distinct thermal behavior between materials, with ablation thresholds and phase transitions captured in good agreement with experimental data.

In parallel, a …


Cfd Modeling And Simulation Of Natural Circulation In Helium- Cooled Very High Temperature Reactors, Mohammad Sakib U. Abrar Jan 2025

Cfd Modeling And Simulation Of Natural Circulation In Helium- Cooled Very High Temperature Reactors, Mohammad Sakib U. Abrar

Dissertations and Theses

This thesis investigates the thermal-hydraulic behavior of natural circulation in helium-cooled Very High Temperature Reactor (VHTR) systems, focusing on the performance and validation of passive safety features under Pressurized or Depressurized Loss of Forced Cooling (P-LOFC or D-LOFC) events. An experimental facility inspired by the General Atomics 350 MWt Modular High Temperature Gas-Cooled Reactor (MHTGR) was developed at The City College of New York. The setup consists of a plenum-to-plenum flow loop with four riser and four downcomer tubes, each equipped with heating coils, thermocouples, and pressure sensors. Natural circulation is driven by density gradients induced by asymmetric heating of …