Nuclear Engineering Commons^™

Space And Defense – Volume Three – Number One – Summer 2009, Space And Defense Journal

Space and Defense

No abstract provided.

Space And Defense – Volume Two – Number Three – Winter 2009, Space And Defense Journal

Space and Defense

No abstract provided.

Space And Defense – Volume Two – Number Two – Winter 2008, Space And Defense Journal

Space and Defense

No abstract provided.

Space And Defense – Volume Two – Number One – Winter 2008, Space And Defense Journal

Space and Defense

No abstract provided.

Space And Defense – Volume One – Number One – Fall 2006, Space And Defense Journal

Space and Defense

No abstract provided.

Measurement Of The 160Gd(P,N)160Tb Excitation Function From 4 18 Mev, Using A Stacked Foil Technique, Ryan K. Chapman

Theses and Dissertations

A stack of thin Gd, Ti, and Cu foils were irradiated with an 18 MeV proton beam at Lawrence-Berkeley National Laboratory's 88-Inch Cyclotron to investigate the ¹⁶⁰Gd(p,n)¹⁶⁰Tb nuclear reaction for nuclear forensics applications. This experiment will improve knowledge of ¹⁶⁰Tb production rates, allowing ¹⁶⁰Tb to be efficiently created in a foil stack consisting of other proton induced isotopes for forensics applications. A set of 15 measured cross sections between 4-18 MeV for ¹⁶⁰Gd(p,n)¹⁶⁰Tb were obtained using a stacked foil technique. The foil stack consisted of one stainless steel, one iron, fifteen gadolinium, …

Analysis Of The Correlation Between Re Filament Surface Features And Tims Performance, Christopher J. Mihal

Theses and Dissertations

Thermal Ionization Mass Spectrometry (TIMS) is an invaluable tool in nuclear forensics as it enables isotopic assays of actinides to be measured, permitting analysis to include special nuclear material isotopic assays, nuclear reactor monitoring, and treaty verification. In one method of measurement for the TIMS system, samples are deposited in solution form on high-purity rhenium filaments. The filaments are heated to evaporate the solvent, and then further heated to cause sample ionization, permitting the sample to be transmitted through a magnetic field which separates ions based on mass to charge ratio into detectors for counting. Heavier ions will be deflected …

The Effect Of Aeration Rate And Free-Floating Carrier Media On The Emission Of Bacillus Globigii In Bioaerosols, Andrew J. Owens

Theses and Dissertations

Aerosols produced by turbulent mechanical mixing and bubble aeration at Waste Water Treatment Plants (WWTPs) become bioaerosols with the entrainment of biological materials. Bioaerosols become a public health risk when human pathogens are present. This study evaluated bioaerosols containing Bacillus globigii (BG) spores, and the effects that aeration rate and the addition of Free-Floating Carrier Media (FFCM) had on the amount of BG spores collected following aerosolization. A series of laboratory-scale experiments investigated two different sizes of floating polystyrene spheres as FFCM and four different aeration rates. When the differences in compared aeration rates were sufficiently large, a positive correlation …

An Assessment Of The Spatial Variation Of Isotopic Ratios In A Candu-6 Reactor For Nuclear Treaty Monitoring, Aaron W. Burkhardt

Theses and Dissertations

The Preparatory Commission for the Comprehensive Nuclear Test Ban Treaty Organization developed the International Monitoring System for monitoring for nuclear explosive testing and compliance with nuclear treaties. Many of the International Monitoring System stations are capable of detecting radionuclides that can be used to determine their origin and creation environment. However, there is not a single unique signature associated with each creation environment. Nuclear reactors, for example, can have a wide range of isotopic concentrations caused by spatial variations in neutron flux intensity and energy. As a single sample only provides a single isotopic measurement, this can make disambiguation difficult …

A Machine Learning Approach To Characterizing Particle Morphology In Nuclear Forensics, Daniel A. Gum

Theses and Dissertations

A machine learning approach is taken to characterizing a group of synthetic uranium bearing particles. SEM images of these lab-created particles were converted into a binary representation that captured morphological features in accordance with a guide established by Los Alamos National Laboratory. Each particle in the dataset contains an association with chemical creation conditions: processing method, precipitation temperature and pH, calcination temperature are most closely tied to particle morphology. Additionally, trained classifiers are able to relate final products between particles, implying that morphological features are shared between particles with similar composition.

Rapid Analysis Of Plutonium Surrogate Material Via Hand-Held Laser-Induced Breakdown Spectroscopy, Ashwin P. Rao

Theses and Dissertations

This work investigated the capability of a portable LIBS device to detect and quantify dopants in plutonium surrogate alloys, specifically gallium, which is a common stabilizer used in plutonium alloys. The SciAps Z500-ER was utilized to collect spectral data from cerium-gallium alloys of varying gallium concentrations. Calibration models were built to process spectra from the Ce-Ga alloys and calculate gallium concentration from spectral emission intensities. Univariate and multivariate analysis techniques were used to determine limits of detection of different emission line ratios. Spatial mapping measurements were conducted to determine the device's ability to detect variations in gallium concentration on the …

Determination Of Lithium Isotope Concentration By Laser Induced Breakdown Spectroscopy Using Chemometrics, Jason C. Wood

Theses and Dissertations

The role of enriched 6Li in nuclear applications makes the ability to detect and monitor lithium enrichment activity imperative. Detecting levels of enrichment of this isotope currently requires sensitive, complex equipment operated by highly-trained technicians, which is prohibitive to rapid detection of enrichment activity. While commercial companies market portable laser induced breakdown spectroscopy (LIBS) with the ability to detect elements on the order or parts per million concentrations, they have not yet been demonstrated to possess the ability to quantitatively determine isotopic concentrations of lithium. This research performs single-pulse LIBS experiments under laboratory conditions to determine concentrations of 7Li and …

Determination And Simulation Of The Neutron Spectrum Of Nuclear Detonations And Surrogate Sources, Taylor M. Nichols

Theses and Dissertations

This research determined a methodology for characterizing the Fast Beam Facility (FBF) at The Ohio State University Nuclear Reactor Laboratory to test the response of photovoltaic arrays to nuclear weapon radiation. Additionally, this research developed neutron and gamma nuclear weapon output spectra of two environments for comparison to the FBF spectrum. A Bonner sphere spectrometer (BSS), coupled with the unfolding program Maximum Entropy Deconvolution (MAXED), was employed as a means of determining the energy spectrum of neutrons. Using the ISO 8529 americium beryllium (AmBe) source as the a priori default spectrum, MAXED was used to unfold the spectrum of neutrons …

Neutron Energy Effects On Asteroid Deflection, Lansing S. Horan Iv

Theses and Dissertations

In the future, a hazardous asteroid will find itself on a collision course with Earth. It is an inevitability; the question is not if, but when. For asteroids of moderate size or larger, a nuclear device is one of humanity's only technologies capable of mitigating this threat via deflection on a timescale of less than a decade. This work examined how changing the output neutron energy from a nuclear device detonation affects asteroid deflection. The notional asteroid target was 300 meters in diameter and composed of silicon dioxide at a bulk density of 1.855 g/cm³. To calculate the …

Neutron Displacement Damage In Germanium Tin Photodiodes, Nathan J. Gale

Theses and Dissertations

GeSn is a promising material for photodiodes in the near-to-mid infrared (IR) spectrum because of new growth methods that enable integration with complementary metal oxide semiconductor (CMOS) technology. While natural germanium has a threshold wavelength of 1800 nm, 6.9 Sn content extends the threshold wavelength to 2700 nm based on a Sn content dependent bandgap. Also, unlike other semiconductors that require liquid nitrogen cooling to act as an IR sensor, GeSn can be operated at room temperature, enabling a wide variety of applications. In this study, photodiodes ranging from 0 to 6.9 tin content were subjected to 1 MeV (Si) …

Analysis Of An Energy Tuning Assembly For Simulating Nuclear Weapon Environments At The National Ignition Facility, Nicholas J. Quartemont, James E. Bevins, Rachel N. Slaybaugh, Lee A. Bernstein

Faculty Publications

An energy tuning assembly ETA was developed to spectrally shape the National Ignition Facility NIF deuterium-tritium D-T fusion neutron source to a notional thermonuclear and prompt fission neutron spectrum TNPFNS to approximate a boosted nuclear device. The spectrally shaped neutron environment can be used to create realistic synthetic post-detonation weapon debris that contain spectrally accurate fission products across all mass chains to enhance U.S. technical nuclear forensics capabilities for nuclear weapon attribution and device reconstruction. This research performed nuclear data covariance analysis through stochastic sampling techniques to predict the performance of an ETA to create the objective TNPFNS, assess anticipated …

Nuclear Data Covariance Analysis In Radiation-Transport Simulations Utilizing Scale Sampler And The Irdff Nuclear Data Library, Nicholas J. Quartemont, Abigail A. Bickley, James E. Bevins

Faculty Publications

This article describes the nuclear data covariance analysis of an experimental design for a neutron energy-tuning assembly (ETA) created to shape a 14-MeV neutron point source to an objective spectrum. Underlying nuclear data uncertainties play a large role in the radiation transport and reaction rates for the range of responses to be expected from an experiment. The methodology leveraged the Standardized Computer Analysis for Licensing Evaluation (SCALE) Sampler module to determine the uncertainty in the neutron transport. The reaction uncertainty was perturbed with the International Reactor Dosimetry and Fusion File v.1.05 uncertainty, correlation matrix, and reaction cross section through multivariate …

Elastic Foundations As Heterogeneous Adventitial Boundary Condition For The Assessment Of Aortic Wall And Peri-Aortic Stiffness From Dense-Mri Data Using Inverse Fem Approach, Johane H. Bracamonte, John S. Wilson, Joao S. Soares

Graduate Research Posters

Background: The establishment of in vivo, patient-specific, and regionally resolved techniques to quantify aortic properties is key for improving risk assessment in clinical practice and scientific understanding of cardiovascular growth and remodeling. Many in vivo studies quantify vascular stiffness using Pulse Wave Velocity. This method provides an averaged measure of stiffness for the entire aorta, ignoring variations in wall stiffness and boundary conditions. Previous studies using Displacement Encoding with Stimulated Echoes Magnetic Resonance Imaging (DENSE-MRI) suggested that the infrarenal abdominal aorta (IAA) deforms heterogeneously throughout the cardiac cycle.

Method: Herein, we hypothesize that the aortic wall strain heterogeneity is driven …

Evaluating The Effectiveness Of Aerospace Materials, Vehicle Shape And Astronaut Position At Lowering The Whole Body Effective Dose Equivalent In Deep Space, Daniel K. Bond

Theses and Dissertations

As future crewed, deep space missions are being planned, it is important to assess how spacecraft design can be used to minimize radiation exposure. Collectively with shielding material, vehicle shape and astronaut position must be used to protect astronauts from the two primary sources of space radiation: Galactic Cosmic Rays (GCR) and Solar Particle Events (SPE). GCRs, which are composed of low intensity, highly energetic, and fully ionized stable and meta-stable isotopes, are considered a chronic source of radiation risk to the astronauts. SPEs, which originate from solar coronal mass ejections, are composed mostly of high intensity protons that can …

Perfusion Cell Seeding And Expansion In Dual Mechanical Stimulation Bioreactor For In Vitro Tissue Development, Sarah Saunders, Sam Coles, Joao S. Soares

Graduate Research Posters

BACKGROUND: Engineered tissues are an exciting potential source of small diameter vascular grafts due to limited supply and patency of available alternatives. Engineered tissue vascular grafts (ETVGs) will provide physiological function that resembles native arteries and maintain the required mechanical properties as they integrate with host tissue. Mechanical stimulation during incubation encourages proper cell alignment and increases extracellular matrix deposition. The enhanced organization of the engineered tissue leads to improved compliance over synthetic alternatives without sacrificing strength and may lead to better integration in vivo.

METHODS: We have developed a bioreactor that mechanically trains grafts during incubation. To test the …

Development Of Near-Real Time Material Detection And Analysis By Coupling Electrochemical & Optical Spectroscopy Methods For Molten Salt Systems, Hunter Andrews

Theses and Dissertations

For both pyroprocessing and molten salt reactors (MSRs), it is desirable from a process control and nuclear safeguards perspective to monitor the species in the molten salts for material accountancy. Many traditional monitoring techniques, even simple salt sample retrieval, are time exhaustive or rendered useless for these systems due to the high thermal loads, high radiation zones, and corrosive nature of molten salts. Therefore, the main motivation for this work is the need for an online monitoring system for a molten salt system that is robust enough to handle the extreme environment yet deliver quantifiable salt concentrations. The intent of …

การพัฒนาผลึกซีเซียมแคลเซียมไอโอไดด์เพื่อใช้ในการตรวจวัดรังสี, ประวิทย์ บัวบาน

Chulalongkorn University Theses and Dissertations (Chula ETD)

งานวิจัยนี้เป็นการพัฒนาผลึกซีเซียมแคลเซียมไอโอไดด์ (CsCaI3) เพื่อใช้ในการตรวจวัดรังสี ผลึกซีเซียมแคลเซียมไอโอไดด์มีสัดส่วนของสารประกอบตั้งต้น คือ ซีเซียมไอโอไดด์และแคลเซียมไอโอไดด์ (CsI:CaI2) ในสัดส่วนโดยน้ำหนักที่แตกต่างกัน คือ 80:20 และ 97:3 ด้วยเทคนิคการเลี้ยวเบนรังสีเอกซ์พบว่า ผลึกทั้งหมดมีโครงสร้างผลึกของรูปแบบผลึก CsI ที่มีระนาบที่โดดเด่นคือ (110) และ (211) มีค่าคงที่แลตทิซ คือ 4.5721±0.0091 และ 4.5512±0.0107 Å เกิดสภาวะความเครียดในผลึกเมื่อเปรียบเทียบกับผลึก CsI อ้างอิง ผลึก CsCaI3 สัดส่วน 80:20 ที่ระนาบ (110) และ (211) มีขนาดผลึก คือ 25.30 และ 25.32 nm ผลึก CsCaI3 สัดส่วน 97:3 ที่ระนาบ (110) และ (211) มีขนาดผลึก คือ 25.10 และ 26.12 nm เห็นได้ว่า การเพิ่มปริมาณแคลเซียมไอโอไดด์ที่สูงขึ้นส่งผลทำให้การจัดเรียงระนาบของโครงสร้างผลึกมีการเปลี่ยนแปลงบ้างเพียงเล็กน้อย สำหรับการวิเคราะห์คุณสมบัติทางแสงผลึก CsCaI3 สัดส่วน 80:20 มีจุดเริ่มโปร่งแสงที่ความยาวคลื่น 439 nm เกิดโปร่งแสงเต็มที่ร้อยละ 65 และมีค่าช่องว่างแถบพลังงาน 2.82, 3.63 และ 3.87 eV ผลึก CsCaI3 สัดส่วน 97:3 จุดเริ่มโปร่งแสงที่ความยาว 426 nm เกิดโปร่งแสงเต็มที่ร้อยละ 49 และมีค่าช่องว่างแถบพลังงาน 2.91 และ 3.45 eV ในส่วนผลตรวจสอบการเปล่งแสงของผลึกด้วยเทคนิคโฟโตลูมิเนสเซนซ์ ผลึก CsCaI3 สัดส่วน 80:20 และ 97:3 ความยาวคลื่นแสงที่เปล่งออกมา 458 nm โดยเปรียบเทียบผลึก CsI(Tl) มีความยาวคลื่นแสงที่เปล่งออกมา …

การพัฒนาผลึกซีเซียมสตรอนเชียมไอโอไดด์เพื่อใช้ในการตรวจวัดรังสี, วศิน ชีวจรัสสกุล

Chulalongkorn University Theses and Dissertations (Chula ETD)

การตรวจวัดรังสีนั้นจำเป็นต้องมีอุปกรณ์ในการตรวจวัดรังสี และอุปกรณ์วัดรังสีมีส่วนประกอบที่สำคัญคือหัววัดรังสี และหัววัดรังสีชนิดผลึกเรืองแสงเป็นที่นิยมใช้งานเนื่องด้วยมีประสิทธิภาพการวัดรังสีที่ดีแต่ว่ามีราคาที่ค่อนข้างแพง ดังนั้นจึงมีความจำเป็นในการพัฒนาผลึกเพื่อใช้การตรวจวัดรังสี ด้วยวิธีการปลูกแบบบริดจ์แมน-สต็อกบาร์เกอร์ที่ปรับปรุงขึ้นเอง โดยศึกษาการเพิ่มปริมาณสัดส่วนของสตรอนเชียมไอโอไดด์ร้อยละ 1, 3 และ 5 จะส่งผลต่อการเปลี่ยนแปลงคุณภาพผลึกและคุณสมบัติทางแสงของผลึกอย่างไร โดยทำการวิเคราะห์โครงสร้างผลึก คุณภาพผลึก และคุณสมบัติทางแสง พบว่าเมื่อปริมาณสัดส่วนสตรอนเชียมไอโอไดด์เพิ่มขึ้นในปริมาณเล็กน้อยนี้ โครงสร้างผลึกและคุณภาพความเป็นผลึกมีการเปลี่ยนแปลงน้อยมาก คือเกิดสภาวะความเครียดแบบบีบอัดในผลึกเพิ่มขึ้นเพียงเล็กน้อย โดยมีค่าคงที่แลตทิชเฉลี่ยเท่ากับ 4.4647 ± 0.0707, 4.5156 ± 0.0370 และ 4.4574 ± 0.0958 Å ทำให้เกิดสภาวะความเครียดแบบบีบอัดในผลึกเป็น -2.23%, -1.12% และ -2.39% และขนาดผลึกมีขนาดใหญ่ขึ้นเล็กน้อยคือ 16.47 ± 0.89, 16.62 ± 0.93 และ 16.72 ± 1.15 nm ตามลำดับ โดยรวมถือว่าไม่ส่งผลเสียต่อโครงสร้างผลึกและคุณภาพความเป็นผลึกเมื่อผสมสตรอนเชียมปริมาณเล็กน้อย แต่ว่าสตรอนเชียมที่ผสมเข้าไปช่วยทำให้แสงที่เปล่งออกมาจากผลึกมีความเข้มของการเปล่งแสงสูงมากขึ้น และแสงมีความยาวคลื่นที่เพิ่มมากขึ้นเป็นประมาณ 595-600 nm สำหรับการทดสอบประสิทธิภาพการตรวจวัดรังสีแกมมาของผลึกขนาด f 1 cm. x 1 cm. พบว่า ผลึกที่มีอัตราส่วนร้อยละ 1, 3 และ 5(หนา 0.5 cm.) มีประสิทธิภาพการวัดรังสีร้อยละ 78.92, 80.54 และ 61.19 และมีความสามารถในการแยกพลังงานรังสี 76.72, 70.62 และ 47.62 ตามลำดับ ของการตรวจวัดรังสีพลังงาน 122 keV และประสิทธิภาพการวัดรังสีลดลงในกรณีการวัดรังสีแกมมาพลังงาน 662 keV เท่ากับ 22.78, 26.10 และ 14.50 ตามลำดับ

Virtual Patient-Specific Vmat Quality Assurance Using Machine Learning In Radiotherapy, Sangutid Thongsawad

Chulalongkorn University Theses and Dissertations (Chula ETD)

The purpose of this study was to develop the virtual patient-specific VMAT QA based on the extracted features from the multileaf collimator (MLC) patterns and fluence map. The machine learning (ML) approach was used to develop the prediction (or regression model) and classification models. The input of models applied Multileaf collimator (MLC) patterns and fluence map as the key features, whereas gamma passing rates (GPR) results from patient-specific VMAT QA of electronic portal imaging devices (EPID) as the label or the response class for testing these models. Sensitivity and specificity scores were calculated for models' accuracy. The highest sensitivity score …

Reducing Material Attractiveness Utilizing Pu-238 And U-232, Cody Lloyd

Theses and Dissertations

Decreasing the material attractiveness of uranium and plutonium materials is crucial to nuclear nonproliferation. The International Atomic Energy Agency (IAEA) implements safeguards across the world on a limited budget. Not only does decreasing material attractiveness reduce the possibility of proliferation, but also may lighten the financial burden on the IAEA if safeguards can be reduced. Two particular isotopes that have negative material attractiveness traits are ²³⁸Pu and ²³²U. Without isotopic separation technology, these isotopes cannot be removed from plutonium and uranium materials respectively. Both ²³⁸Pu and ²³²U produce large quantities of heat by alpha decay. High …

Dose Deposition And Electrostatic Charging Of Kapton Films Irradiated With Electrons, Youssef Abouhussien, Gennady Miloshevsky

Graduate Research Posters

Kapton films are widely utilized in harsh radiation environments where radiation resistant insulating materials are required. For space applications, Kapton polymers are used on satellites as substrates for solar arrays and outer layers of thermal systems. Kapton is also used in nuclear power plants as wire insulation. Kapton materials can be exposed in nuclear reactors to a reactive chemical environment in addition to severe radiation. It is of utmost important to understand how Kapton materials behave under high irradiation conditions and mitigate radiation damage effects. High-energy electrons can deposit ionizing dose and electric charge deeply inside Kapton materials. The charge …

Jxb Force Effects On Beryllium Melt Splashing In Fusion Devices, Cheng Zhang, Gennady Miloshevsky

Graduate Research Posters

Instability and disruption of high-temperature plasma in fusion devices may result in the edge-localized modes (ELMs) and lead to melting of plasma facing components (PFCs) causing their damage. Beryllium (Be) is used as a first wall for PFCs due to its low density, high strength, and high thermal conductivity. However, melting of Be on the surface of first wall is of a great concern as splashing of a molten Be layer will result in the plasma contamination and termination of fusion reaction. Therefore, it is important to understand the physics mechanisms characterizing the splashing of Be from a pool under …

Spatio-Temporal Evolution Of Warm Dense Plasmas: Molecular Dynamics Modeling, Harrison Wenzel, Gennady Miloshevsky

Graduate Research Posters

SPATIO-TEMPORAL EVOLUTION OF WARM DENSE PLASMAS: MOLECULAR

DYNAMICS MODELING Cole Wenzel and Gennady Miloshevsky

Virginia Commonwealth University, Department of Mechanical and Nuclear Engineering, 401

West Main St, Richmond, VA 23284-3015

The exo-atmospheric detonation of nuclear device would be of great impact on the material integrity of orbiting satellites. The spectral energy distribution of high intensity X-ray flux, ~10 28 -10 35 photons/(cm 2 ∙s), originating from a nuclear blast is described by the Planck's blackbody function with the temperature from 0.1 keV to 10 keV. Particular damage would occur to the multi-layered, solar cell panels of satellites. However, the X-ray …

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

Doctoral Dissertations

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

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

Doctoral Dissertations

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