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Full-Text Articles in Mechanical Engineering

Dose Deposition And Electrostatic Charging Of Kapton Films Irradiated With Electrons, Youssef Abouhussien, Gennady Miloshevsky Jan 2020

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 ...


Spatio-Temporal Evolution Of Warm Dense Plasmas: Molecular Dynamics Modeling, Harrison Wenzel, Gennady Miloshevsky Jan 2020

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 ...


Perfusion Cell Seeding And Expansion In Dual Mechanical Stimulation Bioreactor For In Vitro Tissue Development, Sarah Saunders, Sam Coles, Joao S. Soares Jan 2020

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 ...


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 Jan 2020

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 ...


Investigation Of The Coupled Nuclear, Thermal-Hydraulic, And Thermomechanical Response Of A Natural Circulation Research Reactor Under Severe Reactivity-Initiated Accident Transients, Darren G. Talley Mar 2019

Investigation Of The Coupled Nuclear, Thermal-Hydraulic, And Thermomechanical Response Of A Natural Circulation Research Reactor Under Severe Reactivity-Initiated Accident Transients, Darren G. Talley

Mechanical Engineering ETDs

Research reactors play an important role in higher education, scientific research, and medical radioisotope production around the world. It is thus important to ensure the safety of facility workers and the public. This work presents a new reactor transient analysis code, referred to as Razorback, which computes the coupled reactor kinetics, fuel element heat transfer, fuel element thermal expansion and thermal stress, and thermal-hydraulic response of a natural circulation research reactor. The code was developed for the evaluation of large rapid reactivity addition in research reactors, with an initial focus on the Annular Core Research Reactor (ACRR) at Sandia National ...


Compositional Analysis Of Cerium And Cesium In Rapid Setting Cement As An Immobilization Agent For Nuclear Waste, Riyadh M. Motny Jan 2019

Compositional Analysis Of Cerium And Cesium In Rapid Setting Cement As An Immobilization Agent For Nuclear Waste, Riyadh M. Motny

Theses and Dissertations

A feasibility of rapid setting cement (RSC) as an agent of immobilization for certain elements such as fission products or radioactive materials was explored. Cerium (Ce) and cesium (Cs) have been selected as a surrogate for U and/or Pu and fission products, respectively, in this study in three phases. In Phase I, RSC was evaluated for physical properties (e.g., porosity, density, pH values, etc.) using two groups methods—the cement powder at different concentrations of Ce (2 – 10 wt%) with deionized water (DIW) and artificial seawater (ASW). The results showed that the final setting time and compressive strength ...


Call For Abstracts - Resrb 2019, July 8-9, Wrocław, Poland, Wojciech M. Budzianowski Dec 2018

Call For Abstracts - Resrb 2019, July 8-9, Wrocław, Poland, Wojciech M. Budzianowski

Wojciech Budzianowski

No abstract provided.


Flow And Thermal Effects Of Blockages In A Nano-Fluid Cooled Nuclear Fuel Subassembly, Shubham Mandot, N. Govindha Rasu Dec 2018

Flow And Thermal Effects Of Blockages In A Nano-Fluid Cooled Nuclear Fuel Subassembly, Shubham Mandot, N. Govindha Rasu

Symposium on Advanced Sensors and Modeling Techniques for Nuclear Reactor Safety

Nanofluids have a great impact on heat transfer characteristics due to increased thermal conductivity and heat transfer coefficient. In this study, Titanium nanoparticles mixed in liquid sodium has been chosen for analyzing the effect of Nanofluid coolant for a Nuclear Sub- assembly. This study is conducted to observe the effect of nanoparticles on the flow properties and heat transfer characteristics such as velocity, heat transfer coefficient, clad temperature, coolant temperature etc. These effects have been observed for varying nanoparticle concentration and different flow blockage sizes. For this study, 7-pin fuel bundle with and without blockage has been modeled and analyzed ...


Transient Simulation Of Lbe Cooled Chtr Under Natural Circulation With 3d Multi-Physics Code Arch-Th, D. K. Dwivedi, Anurag Gupta, Umasankari Kannan Dec 2018

Transient Simulation Of Lbe Cooled Chtr Under Natural Circulation With 3d Multi-Physics Code Arch-Th, D. K. Dwivedi, Anurag Gupta, Umasankari Kannan

Symposium on Advanced Sensors and Modeling Techniques for Nuclear Reactor Safety

India is developing a 100kWth Compact High Temperature Reactor (CHTR) to facilitate demonstration of technologies for high temperature process heat applications. CHTR is being designed as thorium based TRISO fueled and beryllium oxide moderated prismatic block type vertical core cooled with lead-bismuth eutectic (LBE) under natural circulation for 1000°C outlet. The new concept of high temperature core requires multi-physics multi-scale modeling based tools for investigating the normal operational behavior as well as anticipated transients of CHTR. In view of that, 3D multi-physics code ARCH-TH is being indigenously developed and validated for coupled neutronics-thermal hydraulic benchmarks. The multi-group diffusion based ...


Xenon Dynamics Of Ahwr, Arindam Chakraborty, Baltej Singh Dec 2018

Xenon Dynamics Of Ahwr, Arindam Chakraborty, Baltej Singh

Symposium on Advanced Sensors and Modeling Techniques for Nuclear Reactor Safety

Large core reactors where the core dimension is significantly large compared to the migration length of neutron are more susceptible to xenon instability due to local perturbations. Advanced Heavy Water Reactor (AHWR) is being designed for on-power refueling. Therefore, refueling or movement of control devices in AHWR causes local perturbation. Preliminary modal analysis of AHWR equilibrium core also showed that the eigenvalue separation between fundamental mode and 1st azimuthal mode is small indicating its susceptibility to xenon oscillation in azimuthal plane. Therefore, xenon dynamic studies for AHWR with explicit xenon calculations were carried out using diffusion theory based computer code ...


Heavy Water Concentration Measurement In Air, A. Gupta, D. V. Uduapa, A. Topkar, A. K. Mohanty Dec 2018

Heavy Water Concentration Measurement In Air, A. Gupta, D. V. Uduapa, A. Topkar, A. K. Mohanty

Symposium on Advanced Sensors and Modeling Techniques for Nuclear Reactor Safety

The heavy water in PHWRs flows at high temperature and pressure, hence leaks in the heat transport system are not uncommon. The loss of heavy water due to such leaks can lead to spreading of radioactivity and it also contributes to operating cost of the nuclear reactor. It is advantageous to detect small leaks, because if remains undetected, they may develop into a severe leak, which may lead to reactor shutdown. None of the sensors which are currently in use can meet all the requirement of high sensitivity, and real time measurement which is free from interference from other gamma ...


Transient Analysis Of Primary Feed Pump Trip For 700 Mwe Iphwr, S. Phani Krishna, S. Pahari, S. Hajela, M. Singhal Dec 2018

Transient Analysis Of Primary Feed Pump Trip For 700 Mwe Iphwr, S. Phani Krishna, S. Pahari, S. Hajela, M. Singhal

Symposium on Advanced Sensors and Modeling Techniques for Nuclear Reactor Safety

700 MWe Indian Pressurized Heavy Water Reactor (IPHWR) is a horizontal channel type reactor with two loops of Primary Heat Transport (PHTS) system. Three (two operating and one stand by) main boiler feed water pumps (BFP) supply feed water to Steam Generators (SGs). In the event of one of the running BFP trip, standby comes on line on auto. Transient analysis for this event is performed using in- house computer code ATMIKA.T .The transient has been initiated by tripping one of the pumps.

Two cases are postulated:

1: BFP Trip and Standby BFP available on auto
2: BFP Trip ...


Multi-Grid Acceleration Scheme For Neutron Transport Calculations Using Optimally Diffusive Cmfd Method, Lakshay Jain, Ramamoorthy Karthikeyan, Umasankari Kannan Dec 2018

Multi-Grid Acceleration Scheme For Neutron Transport Calculations Using Optimally Diffusive Cmfd Method, Lakshay Jain, Ramamoorthy Karthikeyan, Umasankari Kannan

Symposium on Advanced Sensors and Modeling Techniques for Nuclear Reactor Safety

Method of characteristics (MOC) is one of the most efficient deterministic techniques for high fidelity neutronic analysis of complex and heterogeneous reactor problems. However, the conventional MOC inner-outer iteration scheme suffers from poor convergence speeds for problems with large scattering to transport cross-section ratio and/or large dominance ratio. This creates a serious hindrance for its effective application to realistic reactor problems. A High Order – Low Order (HO-LO) multi-grid scheme using optimally diffusive coarse mesh finite difference (odCMFD) method has been introduced for improving the performance of code DIAMOND, an assembly level neutronic analysis code based on MOC and unstructured ...


Progress In Micro-Layered Fast Neutron Detectors, Priyarshini Ghosh, W. Fu, Mark J. Harrison, Patrick K. Doyle, Jeremy A. Roberts, D. S. Mcgregor Dec 2018

Progress In Micro-Layered Fast Neutron Detectors, Priyarshini Ghosh, W. Fu, Mark J. Harrison, Patrick K. Doyle, Jeremy A. Roberts, D. S. Mcgregor

Symposium on Advanced Sensors and Modeling Techniques for Nuclear Reactor Safety

The study of accident tolerant fuels is ongoing at the Transient Reactor Test Facility (TREAT) at Idaho National Laboratory. The TREAT Facility provides quick, high-energy neutron pulses that simulate various accident conditions. These neutron pulses are presently detected using an array of fast-neutron detectors called Hornyak buttons. Hornyak buttons suffer from poor detection efficiency and significant Ĉerenkov radiation contamination in the signal. A new enabling technology, the micro-layered fast-neutron detector (MLFD), is presented to monitor neutron flux changes during mild-to-severe reactor accidents. The MLFD was designed to overcome the shortcomings of the Hornyak buttons and to improve detection efficiency. The ...


Matryoshka Inspired Statistical Surrogate For Turbulent Mixing, Abhinav Gairola, Hitesh Bindra Dec 2018

Matryoshka Inspired Statistical Surrogate For Turbulent Mixing, Abhinav Gairola, Hitesh Bindra

Symposium on Advanced Sensors and Modeling Techniques for Nuclear Reactor Safety

Thermalhydraulics of reactor plena is often the most challenging problem due to turbulent mixing, role of jets and stratified flows. Due to which, the safety analysis of the overall reactor vessel or reactor system become complex. Inability of the system level analysis codes to accurately model the role of tur- bulent mixing in scalar transport leads to a major source of uncertainties. The computational cost of accurate CFD models renders the sensitivity studies using those for reactor safety ineffective. Reduced order models are needed which can effectively capture the effects of turbulent mixing and can be used for parametric studies ...


Cfd Simulation Of Hydrodynamics And Scrubbing Behaviour Of Iodine Vapors In A Self-Priming Venturi Scrubber, Paridhi Goel, A. K. Nayak Dec 2018

Cfd Simulation Of Hydrodynamics And Scrubbing Behaviour Of Iodine Vapors In A Self-Priming Venturi Scrubber, Paridhi Goel, A. K. Nayak

Symposium on Advanced Sensors and Modeling Techniques for Nuclear Reactor Safety

In a severe accident scenario, the inadequate heat removal in a nuclear reactor can lead to over pressurization of the containment thus challenging its integrity. If not controlled, this can lead to release of radionuclides and high pressure steam in the environment. To ensure that the containment building remains intact and the reactor depressurizes, the vent line from the reactor is directed to a scrubber tank consisting of multiple venturi scrubbers, metal fiber filter and demister pad (known as Filtered Containment Venting System (FCVS)). This is a passive safety measure suggested for installation in advanced and existing nuclear reactors post ...


Experimental Evaluation Of Critical Heat Flux In Downward-Facing Boiling On Flat Plate Relevant To In-Vessel Retention In Indian Phwrs, Sumit V. Prasad, A. K. Nayak Dec 2018

Experimental Evaluation Of Critical Heat Flux In Downward-Facing Boiling On Flat Plate Relevant To In-Vessel Retention In Indian Phwrs, Sumit V. Prasad, A. K. Nayak

Symposium on Advanced Sensors and Modeling Techniques for Nuclear Reactor Safety

Retention of corium inside the CV and cool it by calandria vault water is essential to mitigate severe accidents in PHWRs. The thermal failure of CV can be prevented by effective decay heat removal on the outer surface of CV using vault water, which depends on the heat transfer behaviour from the outer surface of CV to the vault water. Determination of limiting heat removal capability of vault water through outer surface of calandria vessel is very important. Since, the calandria vessel has a very large diameter and length, the bottom most part of the calandria vessel almost behaves as ...


Enhancements To The Discrete Generalized Multigroup Method, R. L. Reed, J. A. Roberts Dec 2018

Enhancements To The Discrete Generalized Multigroup Method, R. L. Reed, J. A. Roberts

Symposium on Advanced Sensors and Modeling Techniques for Nuclear Reactor Safety

This work seeks to improve the practicality of the discrete generalized multigroup (DGM) method. The DGM method divides a fine-group energy domain into a set of coarse groups. Fine-group fluxes within each coarse group are expanded in an orthogonal basis, and cross section moments are defined to preserve the reaction rates of the fine-group solution. Previous implementations of DGM suffered from large memory requirements, so this work work explores options to reduce the memory footprint by (a) homogenizing cross-section moments over coarse regions and (b) representing discrete-angle dependence through truncated Legendre expansions. Tests were performed using a 1-D, discrete ordinates ...


A Review Of Core Catchers For Advanced Reactors, Samyak Munot, A. K. Nayak Dec 2018

A Review Of Core Catchers For Advanced Reactors, Samyak Munot, A. K. Nayak

Symposium on Advanced Sensors and Modeling Techniques for Nuclear Reactor Safety

In order to address the challenges of severe accident and to ensure safety of people and environment, a core retention device called as “core catcher” has been incorporated in the present and future reactor designs. The concept of core catcher came into existence as early as in early nineties. It is the system which is placed inside the reactor in such a manner that even in the severe accidental scenario, it will retain the corium, quench it and then sustain the coolability of the debris formed due to corium water interactions. From then various approaches to development of core catchers ...


Critical Heat Flux And Power Transients At Low-Pressure Low-Flow Conditions In Vertical Flow Boiling, S. R.G. Vadlamudi, A. K. Nayak Dec 2018

Critical Heat Flux And Power Transients At Low-Pressure Low-Flow Conditions In Vertical Flow Boiling, S. R.G. Vadlamudi, A. K. Nayak

Symposium on Advanced Sensors and Modeling Techniques for Nuclear Reactor Safety

In the advanced boiling water reactor concepts such as AHWR and ESBWR, the recirculation pumps are eliminated in order to simplify the design. During the start-up of such reactors, to establish the natural circulation, the primary coolant has to be heated up slowly in steady steps; it is quite important to determine the characteristics of boiling and critical heat flux (CHF) values in order to establish operational limits. Flow boiling experiments were conducted in an annular channel at very low flow rates and atmospheric pressure varying the inlet subcooling from 20 to 400 C. CHF occurred during the oscillatory flow ...


Non-Optical Imaging Of Flow, Boiling, And Salt Deposition In A Simulated Debris Bed, Molly Ross, Alan Cebula, Steven Eckels, D. S. Mcgregor, Hitesh Bindra Dec 2018

Non-Optical Imaging Of Flow, Boiling, And Salt Deposition In A Simulated Debris Bed, Molly Ross, Alan Cebula, Steven Eckels, D. S. Mcgregor, Hitesh Bindra

Symposium on Advanced Sensors and Modeling Techniques for Nuclear Reactor Safety

Determining flow and heat transfer characteristics in a debris bed or a packed bed is difficult due to the lack of optical access. Non-optical imaging methods, such as x-ray or neutron imaging, can be used to observe flow characteristics and particle deposition, as well as boiling in a packed bed. An amorphous Silicon detector based digital radiography camera can be used to image with either x-rays or neutrons at up to 100 frames per second. The digital radiography camera, coupled with digital image analysis techniques was used to characterize fluid fraction and flow rates in a simulated debris bed. A ...


Thermal Stratification In Liquid Metal Pools Under Cold Transients, Brendan Ward, Hitesh Bindra Dec 2018

Thermal Stratification In Liquid Metal Pools Under Cold Transients, Brendan Ward, Hitesh Bindra

Symposium on Advanced Sensors and Modeling Techniques for Nuclear Reactor Safety

Experimental results are presented for understanding the thermal stratification or mixing in a low Prandtl number, Pr, pool due to the injection of a colder (higher density) jet at the bottom of the pool. In liquid metals (Pr<<1), the higher volumetric thermal expansion enhances buoyant forces, aiding in thermal stratification while the low Pr extends the thermal boundary layer. Rayleigh backscattering with swept wavelength interferometry is used to generate the high fidelity distributed temperature data. The high spatial and temporal resolution of the sensors are required to capture the temperature gradient and fluctuations of temperature allowing more complete understanding of ...


Preliminary Assessment Of Steady-State And Transient Reaction-Rate Measurements At The University Of Wisconsin Nuclear Reactor, J. A. Roberts, T. R. Ochs, D. M. Nichols, W. Fu, Y. Cheng, J. C. Boyington, D. S. Mcgregor, P. P.H. Wilson, R. J. Agasie, C. S. Edwards, Y-H. Park Dec 2018

Preliminary Assessment Of Steady-State And Transient Reaction-Rate Measurements At The University Of Wisconsin Nuclear Reactor, J. A. Roberts, T. R. Ochs, D. M. Nichols, W. Fu, Y. Cheng, J. C. Boyington, D. S. Mcgregor, P. P.H. Wilson, R. J. Agasie, C. S. Edwards, Y-H. Park

Symposium on Advanced Sensors and Modeling Techniques for Nuclear Reactor Safety

Recently, a number of reactor-physics experiments were conducted at the University of Wisconsin Nuclear Reactor (UWNR) using a set of 7 micro-pocket fission detector (MPFD) probes and 3 resistance temperature detector (RTD) probes. The UWNR core is a TRIGA-fueled, MTR conversion using 2x2 fuel bundles separated by coolant channels. Each MPFD probe contained 4 detectors, and each RTD probe contained 6 detectors, all arranged uniformly along the active fuel height. These probes were placed in four different configurations to measure fluxes and temperatures in every accessible coolant channel for a variety of steady-state and transient operations. Relative fluxes can be ...


Micro Structured Sensors For Neutron Detection, D. S. Mcgregor, S. L. Bellinger, J. C. Boyington, Y. Cheng, R. G. Fronk, W. Fu, L. C. Henson, J. D. Hewitt, C. W. Hilger, R. M. Hutchins, K. E. Kellogg, J. A. Medina, D. M. Nichols, T. R. Ochs, M. A. Reichenberger, J. A. Roberts, S. R. Stevenson, T. M. Swope, T. C. Unruh Dec 2018

Micro Structured Sensors For Neutron Detection, D. S. Mcgregor, S. L. Bellinger, J. C. Boyington, Y. Cheng, R. G. Fronk, W. Fu, L. C. Henson, J. D. Hewitt, C. W. Hilger, R. M. Hutchins, K. E. Kellogg, J. A. Medina, D. M. Nichols, T. R. Ochs, M. A. Reichenberger, J. A. Roberts, S. R. Stevenson, T. M. Swope, T. C. Unruh

Symposium on Advanced Sensors and Modeling Techniques for Nuclear Reactor Safety

The shortage of 3He gas, identified as a problem several years ago, initiated research into alternative neutron detectors for various applications. One such technology is the microstructured semiconductor neutron detector (MSND). These compact detectors have microstructures etched deeply into the substrates that are subsequently backfilled with neutron reactive material. Single sided devices typically have thermal neutron detection efficiencies exceeding 30%, while double sided microstructured semiconductor neutron detectors (DS-MSND) have yielded >69% thermal neutron detection efficiency. Both MSNDs and DS-MSNDs have been integrated into compact low-noise and low-power electronics modules. Dosimetry calculations indicate that these detectors can be used as ...


Stratification And Mixing In The Hot Plena Of Liquid Metal-Cooled Reactors, Hitesh Bindra, Brendan Ward, Graham Wilson, Abhinav Gairola Dec 2018

Stratification And Mixing In The Hot Plena Of Liquid Metal-Cooled Reactors, Hitesh Bindra, Brendan Ward, Graham Wilson, Abhinav Gairola

Symposium on Advanced Sensors and Modeling Techniques for Nuclear Reactor Safety

Understanding or modeling the role of stratification and mixing in the plena or containments of nuclear reactors is of prime significance to their safety analysis. Particularly, in case of liquid metal-cooled reactors, thermal stratification in the hot pools under off-normal transients is one of the least understood problems that have multi-physics effects on thermo- mechanics and reactor physics. This is primarily due to lack of high fidelity experimental data for validating CFD or system scale models, which are essential for improved understanding. A scaled liquid metal thermal-hydraulic facility with a scaled hot plenum has been developed at Kansas State University ...


Mcnp Modeling Of A Molten Salt Reactor, David Wall Nov 2018

Mcnp Modeling Of A Molten Salt Reactor, David Wall

Georgia Undergraduate Research Conference (GURC)

GURC Conference – Deadline: 9/21/2018

MCNP Modeling of a Molten Salt Reactor

David Wall and Chris Berry

Mentors:

Dr. Andrew Hummel

Dr. Tien Mun Yee

Dr. Jungkyu Park

Dr. Eduardo B. Farfán

Draft: 9/21/2018

A variety of national and international companies are looking into innovative and nontraditional nuclear reactor systems, known as Generation IV reactors. Recently, there has been an increased interest in a reactor type that uses molten salts of various compositions as nuclear fuel because of its economic and technological advantages. This research study is an exploratory exercise of the nuclear attributes of molten salt ...


Thermal Transport Study On Actinide Oxides Using Phonon Density Of States Calculation, Alex Resnick, Katherine Mitchell Nov 2018

Thermal Transport Study On Actinide Oxides Using Phonon Density Of States Calculation, Alex Resnick, Katherine Mitchell

Georgia Undergraduate Research Conference (GURC)

The thermophysical properties of nuclear fuels being developed in generation IV nuclear reactors are still being widely examined since the reactor’s operating performance is strongly correlated to the thermal transport properties of the fuel source. In this research, phonon density of states (DOS) are estimated for uranium dioxide (UO2), thorium dioxide (ThO2), and plutonium dioxide (PuO2) as these are all significant representations of the actinide oxide family. The crystalline structures of these fuels are altered to contain point defects in the form of primary atom vacancies, oxygen vacancies, and uranium substitution. Primary atom and oxygen vacancies ...


Detector Arrays For Nuclear Security And Safeguards Applications, Jessica Hartman May 2018

Detector Arrays For Nuclear Security And Safeguards Applications, Jessica Hartman

UNLV Theses, Dissertations, Professional Papers, and Capstones

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


Analysis Of High Temperature Effects On Piezoelectric Based Ultrasonic Transducers, Prathamesh Bilgunde Jan 2018

Analysis Of High Temperature Effects On Piezoelectric Based Ultrasonic Transducers, Prathamesh Bilgunde

Graduate Theses and Dissertations

Under sodium viewing (USV) using ultrasonic pulse-echo techniques offers the potential for the inspection of generation IV, liquid sodium-cooled fast reactors (SFRs) at the hot stand-by temperature (260C). However, the harsh environment effects on the transducer reduce the ultrasonic signal strength which also limits the probability of detection (POD) of the defects.

Current work presents a unified modeling and measurement-based methodology to analyze the high temperature effects on the transducer components. Resonance analysis-based characterization has shown that the conventional d33 piezoelectric parameter is not a sufficient condition to estimate resonance characteristics of high temperature ultrasonic transducers. A full piezoelectric material ...


Experimental Evaluation Of Uranyl Transport Into Mesoporous Silica Gel Using Fluorescence, Brandon M. Dodd Jan 2018

Experimental Evaluation Of Uranyl Transport Into Mesoporous Silica Gel Using Fluorescence, Brandon M. Dodd

Theses and Dissertations

This research investigated parameters that can affect the use of nanoporous silica gel as a media for accumulating a detectable amount of uranium. The unique fluorescence of the Uranyl (UO22+) ion was used to evaluate the transport kinetics and accumulation within silica gel in a static fluid and under pressure driven flow. The addition of fluid flow decreased the time constant from on the order of an hour to approximately 2s with a very low fluid velocity of 0.36cm/s. The 0.36cm/s fluid velocity was found to be the critical velocity above which there was ...