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Full-Text Articles in Nuclear Engineering

Calculation And Tabulation Of Efficiencies For Tungsten Foil Positron Moderators, R. Alsulami, M. Albarqi, S. Jaradat, Shoaib Usman, Joseph T. Graham May 2019

Calculation And Tabulation Of Efficiencies For Tungsten Foil Positron Moderators, R. Alsulami, M. Albarqi, S. Jaradat, Shoaib Usman, Joseph T. Graham

Mining and Nuclear Engineering Faculty Research & Creative Works

Monte Carlo radiation transport simulations were used to calculate the positron stopping profiles in tungsten positron moderator foils. Stopping profiles were numerically integrated with efficiency kernels derived from Green's function solutions of the 3D diffusion equation to determine the moderation efficiency in both the backscattering and transmission geometries. Stopping profiles and efficiencies were calculated for positron energies from 10 keV to 10 MeV and incident angles from 0° to 75°. The resulting efficiencies agreed with other calculated and measured values in the literature, especially when similar values of the positron diffusion length and surface emission branching ratio were used ...


Experimental Investigation Of Liquid Contact In The Developing Post-Dryout Chf Flow Boiling Regime Using Surface Mounted Thermistors, Hiralkumar Harshadbhai Patel Jan 2019

Experimental Investigation Of Liquid Contact In The Developing Post-Dryout Chf Flow Boiling Regime Using Surface Mounted Thermistors, Hiralkumar Harshadbhai Patel

Doctoral Dissertations

"Understanding heat transfer in the post-critical heat flux (CHF) flow boiling regime is important for determining the performance of the heat transfer equipment for various industrial applications requiring high heat transfer rates, e.g., heat exchangers, boilers, chemical and nuclear reactors. Liquid can be present in the core of the flow channel in the form of entrained liquid droplets, especially immediately downstream of film dryout. These droplets are suspected to provide an important heat transfer mechanism as they impinge on the heated wall. The objective of the current study is to investigate liquid contact with the heated wall in this ...


Radiation Detector Deadtime And Pile Up: A Review Of The Status Of Science, Shoaib Usman, Amol Patil Oct 2018

Radiation Detector Deadtime And Pile Up: A Review Of The Status Of Science, Shoaib Usman, Amol Patil

Mining and Nuclear Engineering 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 ...


Direct Synthesis Of Radioactive Nanoparticles Involving Neutrons, Carlos Henry Castano Giraldo, Maria Camila Garcia Toro, Brian Michael Mills Aug 2018

Direct Synthesis Of Radioactive Nanoparticles Involving Neutrons, Carlos Henry Castano Giraldo, Maria Camila Garcia Toro, Brian Michael Mills

Mining and Nuclear Engineering 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 ...


Advancement In Thermal Energy Storage Using Phase Change Materials, Rami Mohammad Reda Saeed Jan 2018

Advancement In Thermal Energy Storage Using Phase Change Materials, Rami Mohammad Reda Saeed

Doctoral Dissertations

"The dissertation is intended to study the fundamental physical behavior of phase change materials (PCMs) and provide a comprehensive overview of the state of the art in their design and applications for thermal energy storage. Standard, predictive and thermodynamic models were presented to develop new PCM eutectic mixtures in a more scientific design approach. As new eutectic PCMs were developed, further research efforts were initiated to develop functionalized PCMs with enhanced thermal and physical properties to create the next generation of PCMs. Further efforts have been expanded to review several high-temperature PCM candidates with phase transition temperatures in the range ...


Computational Design And Numerical Analyses Of Thermal-Hydraulics In A Pwr-Type Small Modular Nuclear Reactor, Vivek Murlidhar Rao Jan 2018

Computational Design And Numerical Analyses Of Thermal-Hydraulics In A Pwr-Type Small Modular Nuclear Reactor, Vivek Murlidhar Rao

Doctoral Dissertations

"This dissertation focuses on computational design of a PWR-type small modular nuclear reactor (SMR), and analysis of coolant thermal-hydraulics during steady-state operation. Physical design of the SMR is based on the existing AP-1000 and Small Modular Reactor designs by Westinghouse Nuclear.

The first paper discusses a two-stage simulation of turbulent flow in the lower plenum of the RPV. In the first stage, four time-dependent Reynolds-Averaged Navier-Stokes (RANS) based turbulence models were used to simulate turbulent flow, compare predictions and identify an appropriate turbulence model. In the second stage, the selected turbulence model was once again used to simulate flow on ...


Design And Development Of A Compact X-Ray Tube For Stationary Ct Architecture, Ashish Vighnahar Avachat Jan 2018

Design And Development Of A Compact X-Ray Tube For Stationary Ct Architecture, Ashish Vighnahar Avachat

Doctoral Dissertations

"Multisource architectures enable sweeping one or more x-ray beams across the imaging field-of-view faster than physically moving a single x-ray source and/or a detector. Hence, these architectures are attractive for the applications in which temporal resolution plays an important role, for example, cardiac computed tomography (CT) or real-time CT. One of the recent developments in multisource architectures for CT imaging is stationary CT architecture, whereby two separate stationary arrays -- one for x-ray sources and one for detectors -- are utilized to sweep one or more x-ray beams along the gantry and acquire 360 degree projections. To have a stationary CT ...


Investigation Of The Hydrodynamics And Scale-Up Of Advanced Triso Nuclear Fuel Manufacturing Using Sophisticated Measurement Techniques, Thaar M. Aljuwaya Jan 2018

Investigation Of The Hydrodynamics And Scale-Up Of Advanced Triso Nuclear Fuel Manufacturing Using Sophisticated Measurement Techniques, Thaar M. Aljuwaya

Doctoral Dissertations

"The successful performance and safety of the Very-High-Temperature Nuclear Reactors (VHTR) extremely depend on the quality of the TRISO nuclear fuel coated particles. However, the coating of the TRISO particles is delicate process and impacted by the hydrodynamics of spouted beds. Therefore, in this work, we applied advanced non-invasive measurement techniques which are gamma-ray computed tomography (CT) and radioactive particle tracking (RPT), to investigate foremost the local parameters to advance the fundamental understanding of the hydrodynamics and scale-up of gas-solid spouted beds. The CT technique has been applied to study the effects of particle density, particle size, bed size, and ...


Customized Multi-Group Cross Section Generation With Njoy For Discrete Ordinates Computed Tomography And Radiography Simulation, Steven Michael Wagstaff Jan 2018

Customized Multi-Group Cross Section Generation With Njoy For Discrete Ordinates Computed Tomography And Radiography Simulation, Steven Michael Wagstaff

Masters Theses

"The purpose of this work was to explore the creation of photoatomic multi-group cross section libraries to be used with a software package DOCTORS (Discrete Ordinates Computed TOmography and Radiography Simulator). This software solves the linear Boltzmann equation using the discrete ordinates method [1]. To create these libraries, NJOY2016 was used, creating both fine and broad energy multi-group cross section files. The cross section's accuracy was tested against an equivalent Monte Carlo simulation using MCNP6.

Two simulation geometries were used. The first, a cylindrical water phantom with a single source projection placed in front, simulating an X-ray radiography. The ...


Fuel Burnup Simulation And Analysis Of The Missouri S&T Reactor, Joshua Hinkle Rhodes Jan 2018

Fuel Burnup Simulation And Analysis Of The Missouri S&T Reactor, Joshua Hinkle Rhodes

Masters Theses

"The purpose of this work is to simulate the fuel burnup of the Missouri S&T Reactor. This work was accomplished using the Monte Carlo software MCNP. The primary core configurations of MSTR were modeled and the power history was used to determine the input parameters for the burnup simulation. These simulations were run to determine the burnup for each fuel element used in the core of MSTR.

With these simulations, the new predicted isotopic compositions were added into the model. New core configurations were determined, and the burnup corrected model was used to predict the excess reactivity and control ...


Modulated Photothermal Radiometry: Detector Sensitivity Study And Experimental Setup, Jessica Nicole Seals Jan 2018

Modulated Photothermal Radiometry: Detector Sensitivity Study And Experimental Setup, Jessica Nicole Seals

Masters Theses

"This thesis outlines the development of a system used for determining the surface thermal diffusivity of both non-irradiated and irradiated materials. The motivation for this work is to establish a modulated photothermal radiometry (PTR) system on the campus of Missouri University of Science and Technology. One of the main efforts described in this thesis is the design and construction of the physical apparatus. Along the way, it was necessary to perform a detailed sensitivity analysis of the system to determine whether the expected signal emitted from the sample falls within the bounds of detectivity for the HgCdTe (MCT) detector used ...


Correlation Between Delay Time And Measured Concentration And Concentration Uncertainty By Neutron Activation Analysis, James Thomas Seman Jan 2018

Correlation Between Delay Time And Measured Concentration And Concentration Uncertainty By Neutron Activation Analysis, James Thomas Seman

Doctoral Dissertations

"For the last several decades, it has been apparent that new methods of identifying explosives can help investigators trace their origins. One way to identify an explosive is through the use of taggants: materials added to a product that encodes information about the product such as when it was manufactured.

This research investigates the survivability of a new identification taggant called the Nuclear Barcode that overcomes some of the downfalls that have been identified in prior taggants. The Nuclear Barcode encodes information as a unique combination of concentrations of rare earths (Ho, Eu, Sm, Lu, and Dy) and precious metals ...


The Significance Of Grouping And Missed Bubbles On Interfacial Area Concentration And Void Fraction, Chandller Stephen-Leslie Mills Jan 2018

The Significance Of Grouping And Missed Bubbles On Interfacial Area Concentration And Void Fraction, Chandller Stephen-Leslie Mills

Doctoral Dissertations

"The two-fluid model is used in nuclear reactor safety codes. Two of the important constitutive relations will be discussed in this study, the interfacial area concentration and void fraction. The Interfacial area concentration is directly affected by the number of bubbles and how these bubbles are categorized into groups. In this study, a new algorithm was implemented to account for trailing bubbles, bubbles with short response times, and the categorization of bubbles based upon diameter for all group 1 bubbles. The optical and conductivity probes were used to determine the void fraction and interfacial area concentration in a bubble column ...


Development And Monte Carlo Validation Of A Finite Element Reactor Analysis Framework, Wayne J. Brewster Jan 2018

Development And Monte Carlo Validation Of A Finite Element Reactor Analysis Framework, Wayne J. Brewster

Masters Theses

"This study presents the development and Monte Carlo validation of a continuous Galerkin finite element reactor analysis framework. In its current state, the framework acts as an interface between the mesh preparation software GMSH and the sparse linear solvers in MATLAB, for the discretization and approximation of 1-D, 2-D, and 3-D linear partial differential equations. Validity of the framework is assessed from the following two benchmarking activities: the 2-D IAEA PWR benchmark; and the 2-D Missouri Science and Technology Reactor benchmark proposed within this study. The 2-D IAEA PWR multi-group diffusion benchmark is conducted with the following discretization schemes: linear ...


An Investigation Into The Effects Of Ion Tracks On Α-Quartz, Bryant Alan Kanies Jan 2018

An Investigation Into The Effects Of Ion Tracks On Α-Quartz, Bryant Alan Kanies

Masters Theses

"The passage of a swift heavy ion through a material can cause columnar, amorphous nano-structures known as ion tracks. Swift heavy ions are present in a number of applications ranging from nuclear reactors to nuclear waste storage and onboard spacecraft. The study of ion tracks has been ongoing since the late 1950s and has led to several technological advancements. In fact, ion beams have been used to enhance material properties and aid in the production of electrical components. Ion beams, and their resultant ion tracks, can therefore be seen as a method to purposefully alter material properties such as thermal ...


Nuclear Fusion As A Primary Energy Production Method, Joshua Eiswirth Aug 2017

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 ...


Discrete Ordinates Ct Organ Dose Simulator (Doctors), Edward T. Norris Jan 2017

Discrete Ordinates Ct Organ Dose Simulator (Doctors), Edward T. Norris

Doctoral Dissertations

"Computed tomography (CT) has become pervasive in medical diagnostics as improved imaging techniques and processing algorithms provide higher quality information to doctors. However, the exponentially increasing usage of CT has raised concerns regarding long term low-dose radiological risks.

Currently, the dose to patients is computed using Monte Carlo methods and experimental tests. In other areas of radiation transport, deterministic codes have been shown to be much faster than Monte Carlo codes.

Currently, no deterministic methodology exists to automatically generate a spatially distributed dose profile from a CT voxel phantom. This work proposes a new code, Discrete Ordinate CT Organ Dose ...


Gamma Spectroscopy By Artificial Neural Network Coupled With Mcnp, Huseyin Sahiner Jan 2017

Gamma Spectroscopy By Artificial Neural Network Coupled With Mcnp, Huseyin Sahiner

Doctoral Dissertations

"While neutron activation analysis is widely used in many areas, sensitivity of the analysis depends on how the analysis is conducted. Even though the sensitivity of the techniques carries error, compared to chemical analysis, its range is in parts per million or sometimes billion. Due to this sensitivity, the use of neutron activation analysis becomes important when analyzing bio-samples. Artificial neural network is an attractive technique for complex systems. Although there are neural network applications on spectral analysis, training by simulated data to analyze experimental data has not been made. This study offers an improvement on spectral analysis and optimization ...


Design And Analysis Of A Passive Heat Removal System For A Small Modular Reactor Using Star Ccm+, Raymond Michael Fanning Jan 2017

Design And Analysis Of A Passive Heat Removal System For A Small Modular Reactor Using Star Ccm+, Raymond Michael Fanning

Masters Theses

"Next generation nuclear power plants, specifically small modular reactor designs, are the best alternative to fossil fuels for power generation due to their power density and low carbon emissions and constant awareness of safety concerns. A promising safety feature of new designs is the removal of heat by passive systems in accident scenarios. The passive systems require no moving parts and no intervention by personnel. These systems must be accurately simulated for better understanding of the heat transport phenomena: natural convection cooling. Due to the fact that most work developing these passive heat removal systems are proprietary information, a passive ...


Cfd Validation And Scaling Of Condensation Heat Transfer, Varun Kalra Jan 2017

Cfd Validation And Scaling Of Condensation Heat Transfer, Varun Kalra

Masters Theses

"A CFD study was performed using STAR-CCM+ to validate the software for its competence in the prediction and scaling of condensation heat transfer in the presence of air acting as a non-condensable gas. Three vertical concentric tube heat exchanger geometries with different diameters were studied in the CFD analysis. It was seen that the steam bulk temperatures predicted by STAR-CCM+ closely matched the experimental data. However, the temperatures of outer wall of the steel condenser tubes showed a deviation of 2% to 11% from the experimental values. The error in adiabatic water wall temperatures were found to range from 18 ...


Analysis And Implementation Of Accident Tolerant Nuclear Fuels, Benjamin Joseph Prewitt Jan 2017

Analysis And Implementation Of Accident Tolerant Nuclear Fuels, Benjamin Joseph Prewitt

Masters Theses

"To improve the reliability and robustness of LWR, accident tolerant nuclear fuels and cladding materials are being developed to possibly replace the current UO2/zirconium system. This research highlights UN and U3Si2, two of the most favorable accident tolerant fuels being developed. To evaluate the commercial feasiblilty of these fuels, two areas of research were conducted. Chemical fabrication routes for both fuels were investigated in detail, considering UO2 and UF6 as potential starting materials. Potential pathways for industrial scale fabrication using these methods were discussed.

Neutronic performance of 70%UN-30%U3Si2 ...


The Viability Of Advantg Deterministic Method For Synthetic Radiography Generation, Andrew Albert Bingham Jan 2017

The Viability Of Advantg Deterministic Method For Synthetic Radiography Generation, Andrew Albert Bingham

Masters Theses

"Time sensitive and high resolution image simulations are needed for synthetic radiography generation. The standard stochastic approach requires lengthy run times with poor statistics at higher resolutions. The investigation of the viability of a deterministic approach to synthetic radiography image generation was explored. The aim was to analyze a computational time decrease over the stochastic method. ADVANTG was compared to MCNP in multiple scenarios including a Benchtop CT prototype, to simulate high resolution radiography images. By using ADVANTG deterministic code to simulate radiography images the computational time was found to decrease over 10 times compared to the MCNP stochastic approach ...


Comparison Of ²⁵²Cf Time Correlated Induced Fission With Amli Induced Fission On Fresh Mtr Research Reactor Fuel, Jay Prakash Joshi Jan 2017

Comparison Of ²⁵²Cf Time Correlated Induced Fission With Amli Induced Fission On Fresh Mtr Research Reactor Fuel, Jay Prakash Joshi

Masters Theses

"The effective application of international safeguards to research reactors requires verification of spent fuel as well as fresh fuel. To accomplish this goal various nondestructive and destructive assay techniques have been developed in the US and around the world. The Advanced Experimental Fuel Counter (AEFC) is a nondestructive assay (NDA) system developed at Los Alamos National Laboratory (LANL) combining both neutron and gamma measurement capabilities. Since spent fuel assemblies are stored in water, the system was designed to be watertight to facilitate underwater measurements by inspectors. The AEFC is comprised of six 3He detectors as well as a shielded ...


Studies On Neutron Diffraction And X-Ray Radiography For Material Inspection, Fahima Fahmida Islam Jan 2017

Studies On Neutron Diffraction And X-Ray Radiography For Material Inspection, Fahima Fahmida Islam

Doctoral Dissertations

"Among the different probes to study the structures of the bio and structural materials, X-ray and neutron are widely used because of their distinctive usefulness in investigating different structures. X-ray radiography and neutron diffraction are two widely known non-destructive techniques for material inspection. Here we demonstrate the design of neutron diffractometer with low power source and analyze the digital image produced by the X-ray radiography instead of neutron diffraction because of the availability of the data. Neutron diffraction is a powerful tool for understanding the behavior of crystal structures and phase behaviors of materials. While neutron diffraction capabilities continue to ...


Integrated Microsphere Whispering Gallery Mode Probe For Highly Sensitive Refractive Index Measurement, Hanzheng Wang, Lei Yuan, Cheol-Woon Kim, Jie Huang, Xinwei Lan, Hai Xiao Jun 2016

Integrated Microsphere Whispering Gallery Mode Probe For Highly Sensitive Refractive Index Measurement, Hanzheng Wang, Lei Yuan, Cheol-Woon Kim, Jie Huang, Xinwei Lan, Hai Xiao

Mining and Nuclear Engineering Faculty Research & Creative Works

We report an integrated whispering gallery mode microresonator-based sensor probe for refractive index sensing. The probe was made by sealing a borosilicate glass microsphere into a thin-wall glass capillary pigtailed with a multimode optical fiber. The intensities of the resonant peaks were found decreasing exponentially (linearly in a log scale) with the increasing refractive index of the medium surrounding the capillary. The sensing capability of the integrated probe was tested using sucrose solutions of different concentrations and the resolution was estimated to be about 2.5 x 10-5 in the index range of 1.3458 to 1.3847. The ...


Temperature Measurements During High Flux Ion Beam Irradiations, M. L. Crespillo, Joseph T. Graham, Y. Zhang, W. J. Weber Feb 2016

Temperature Measurements During High Flux Ion Beam Irradiations, M. L. Crespillo, Joseph T. Graham, Y. Zhang, W. J. Weber

Mining and Nuclear Engineering Faculty Research & Creative Works

A systematic study of the ion beam heating effect was performed in a temperature range of -170 to 900 °C using a 10 MeV Au3+ ion beam and a Yttria stabilized Zirconia (YSZ) sample at a flux of 5.5 x 1012 cm-2 s-1. Different geometric configurations of beam, sample, thermocouple positioning, and sample holder were compared to understand the heat/charge transport mechanisms responsible for the observed temperature increase. The beam heating exhibited a strong dependence on the background (initial) sample temperature with the largest temperature increases occurring at cryogenic temperatures and decreasing with increasing ...


Proactive Strategies In Personal Dose Monitoring, Prevention And Mitigation, Manish Kumar Sharma Jan 2016

Proactive Strategies In Personal Dose Monitoring, Prevention And Mitigation, Manish Kumar Sharma

Doctoral Dissertations

"At certain threshold, nuclear radiation (like x-rays and gamma-rays) may adversely impact the health of living tissues. The exposure to these radiations in nuclear facilities is measured by devices called dosimeters. The devices are generally worn on the torso and are monitored by health physics division to report the radiation dose received by the personnel. However, this approach is not proactive--since the dosimeters reflect the dose that has already been absorbed in the body of the wearer.

This work presents a scheme to proactively avoid large dose acquisition at radiation-prone facilities. The work was divided into three major segments: (i ...


Synthesis Of Radioactive Nanostructures In A Research Nuclear Reactor, Maria Camila Garcia Toro Jan 2016

Synthesis Of Radioactive Nanostructures In A Research Nuclear Reactor, Maria Camila Garcia Toro

Masters Theses

In this work, the synthesis of radioactive nanostructures by water radiolysis was studied. The irradiation processes were done in the Missouri University of Science and Technology research nuclear reactor (MSTR).

Radioactive gold nanoparticles (AuNPs) were synthesized from aqueous solutions containing the metal salt precursors by radiolysis of water. Seven different samples were irradiated at 200kW of thermal power for 0.5, 1, 3, 5, 10, 30, and 60 minutes. The average sizes of the obtained nanoparticles ranged from 3 nm to 400 nm, it was found that the particle size decreased with the irradiation time. Some agglomerations of particles were ...


Thermal Characterization Of Phase Change Materials For Thermal Energy Storage, Rami Mohammad Reda Saeed Jan 2016

Thermal Characterization Of Phase Change Materials For Thermal Energy Storage, Rami Mohammad Reda Saeed

Masters Theses

"The study provides a valuable and useful database for Phase Change Materials (PCMs) for Thermal Energy Storage (TES) applications. Only a few existing studies have provided an overall investigation of thermophysical properties of PCMs in this detailed manner. Several organic PCMs, namely Myristic acid, Capric Acid, Lauryl Alcohol, Palmitic acid and Lauric acid, have been characterized after being carefully selected to cover wide range of TES applications. Insights and information gained from this work will be applied toward the design and modelling of many low temperature thermal energy storage applications. The study experimentally investigated uncertainty of thermal characterization of PCMs ...


Deterministic Simulation Of Thermal Neutron Radiography And Tomography, Rajarshi Pal Chowdhury Jan 2016

Deterministic Simulation Of Thermal Neutron Radiography And Tomography, Rajarshi Pal Chowdhury

Masters Theses

"In recent years, thermal neutron radiography and tomography have gained much attention as one of the nondestructive testing methods. However, the application of thermal neutron radiography and tomography hindered by their technical complexity, radiation shielding, and time-consuming data collection processes. Monte Carlo simulations have been developed in the past to improve the neutron imaging facility's ability. In this present work, a new deterministic simulation approach has been proposed and demonstrated to simulate neutron radiographs numerically using a ray tracing algorithm. This approach has made the simulation of neutron radiographs much faster than by previously used stochastic methods (i.e ...