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Nuclear Engineering - Bachelor's degree

Mostrando recursos 1 - 20 de 132

  1. Telluridm-induced corrosion of structural alloys for nuclear applications in molten salts

    Skowronski, Natasha (Natasha C.)
    The mechanism by which tellurium causes intergranular corrosion (IGC) of structural alloys in molten salt reactors is currently poorly understood. Limited corrosion testing has been performed on a few select alloys in simulated reactor conditions. In this thesis, the results of performing 50 h, 100 h, and 150 h corrosion tests on alloys Hastelloy N, Nickel-201, Incoloy 8ooH, and 316L Stainless Steel are presented. Upon inspection of the corroded surfaces of each alloy after its immersion in molten LiF-NaF-KF (FLiNaK) salt at 700 °C using scanning electron microscopy (SEM) and energy-dispersive x-ray spectroscopy (EDS), a consistent corrosion rate could not...

  2. Irradiated recycled plastic as a concrete additive for improved chemo-mechanical properties in hardened cement pastes

    Schaefer, Carolyn (Carolyn E.)
    Portland cement based concrete production contributes heavily to greenhouse gas emissions. Thus a need exists for the development of durable and sustainable concrete with a lower carbon footprint. This can be achieved when Portland cement is partially replaced with another material without compromising the concrete's strength. The use of waste plastics in concrete has been explored as a means of improving concrete's mechanical properties while also providing an efficient way to both re-purpose waste plastic and partially displace cement for the purpose of reducing carbon emissions. This replacement, however, typically comes with a sacrifice of compressive strength. This work discusses...

  3. Radiation damage quantification in elemental copper using Wigner energy storage

    Carter, Ki-Jana
    Radiation damage in materials can cause critical components in fission and fusion reactors to fail with potentially catastrophic consequences. Radiation damage quantification is essential for understanding, predicting, and preventing such failures. The current unit of radiation damage, displacements per atom (DPA), is not a measurable quantity, and it is known to be an inaccurate measure of radiation damage. This project aims to quantify radiation damage accurately and measurably by characterizing the storage of energy in radiation-induced material defects, known as Wigner energy storage. In order to gain an atomistic understanding of radiation damage, the irradiation and calorimetry of elemental copper...

  4. A combined radiographic and time-of-flight method for zero-knowledge warhead verification

    Hecla, Jake J
    A novel means of combined spectroscopic and radiographic zero-knowledge warhead verification has been developed and investigated using Monte Carlo simulations. This verification approach, henceforth called "epi-ZK," uses time-structured beams of epithermal neutrons to verify weapon isotopics and geometry without creating or transmitting meaningful information about the device design. This method seeks to remedy information security and hoax resistance issues inherent in previously proposed zero-knowledge verification methods such as fast neutron radiography with preloaded detector arrays and NRF based methods. By using a combination of epithermal neutron radiography and time-of-flight analysis, the epi-ZK method achieves sensitivity to subtle isotopic and geometric...

  5. High-fidelity simulations of transverse electric waves propagating through Alcator C-Mod

    Major, Maximillian R
    This project represents an attempt to model the propagation of microwaves into Alcator C-Mod's plasma in high fidelity and with a reduced number of degrees of freedom. The success of this endeavor would accelerate progress within the field of fusion energy, as simulations of C-Mod's plasmas, or other plasmas in general, can be run more quickly while still maintaining their accuracy. The main procedure involves producing simulations within COMSOL that use mode numbers based on a power spectrum of waves at 4.6 GHz. These simulations are then overlaid to model how the waves will propagate as a function of position,...

  6. Diverting steam created in a nuclear reactor to produce electricity more economically

    Shifflet, Natalie J
    Nuclear power is not as economically competitive as other electricity generation methods. To increase the use of nuclear power, nuclear power must become more profitable. A way to accomplish this is by storing superfluous energy during times of low energy prices to be used when the electricity price is greater. This could be done by varying the load to the turbine by diverting steam from before the turbine while the nuclear reactor runs at full power. In order to understand this project idea of diverting steam to a thermal storage to increase profit, literature on nuclear systems, steam turbines, and...

  7. Quantifying the fouling resistance of Accident-Tolerant Fuel (ATF) cladding coatings with force spectroscopy

    Auguste, Rasheed
    CRUD (Chalk River Unidentified Deposits) is buildup of metal oxides on the interior of nuclear reactors. This is caused by corrosion in reactor internals, leading to problems such as coolant contamination in porous deposits left by CRUD. CRUD has forced many nuclear reactors into temporary shutdown or production downgrades, costing millions of dollars US per reactor. If the CRUD growth factors could be fully understood, they could be controlled, and the CRUD problem could be eliminated altogether. Atomic force microscopy can be used to measure the force, or the strength of the CRUD-clad bond with different materials. This research focuses...

  8. Assessing the applicability of the ASME V&V20 standard for uncertainty quantification of CFD in nuclear systems fluid modeling

    Alvarez, Andres Felipe, S.B. Massachusetts Institute of Technology
    Advanced modelIng and sImulatIon (M&S) of nuclear systems could offer a key contrIbutIon In enhancIng the competItIveness and safety performance of nuclear power plants. Large multI-organIzatIonal InItIatIves such as the ConsortIum for Advanced SImulatIon of LIght Water Reactors (CASL) and the Nuclear Energy Advanced ModelIng and SImulatIon (NEAMS) emphasIzes the Importance of M&S research to the U.S. nuclear Industry. UncertaInty QuantIfIcatIon (UQ) represents a fundamental area of research necessary to expand the applIcatIon of M&S Into nuclear Industry, but the fIeld Is stIll not mature, and no general consensus exIsts on current UQ methods. In thIs study, the ASME V&V20...

  9. Construction of a model for the improved planning of MCO-informed VMAT in RayStation using a knowledge base of clinical IMRT-MCO treatment plans

    Colbert, Caroline M
    Intensity Modulated Radiation Therapy (IMRT) is a type of external beam radiation therapy that has proven effective at treating many cancers. A related therapy type, Volumetric Modulated Arc Therapy (VMAT), has the potential to provide comparable dose coverage to tumor sites while better sparing nearby organs at risk (OARs). Multi-criteria Optimization (MCO) is an algorithm that is used to optimize a patient's personalized IMRT treatment plan. VMAT treatment plans cannot be optimized using early versions of the MCO algorithm. The purpose of this study was to construct a model for the automated generation of VMAT treatment plans for prostate cancers...

  10. The economic and political significance of Russia's RBMK reactors

    Corney, Daniel E
    The safety of continued operations of Russian Raktor Bolshoy Moshchnosti Kanalnyy (RBMK) reactors is often questioned. The original RBMK design was riddled with deficiencies in its shutdown procedures resulting in unsafe operation under certain conditions, most notably resulting in the April 26th Chernobyl disaster. Despite implementing modifications to correct these problems, almost all countries permanently cancelled existing RBMK reactor operations. The sole exception to the European decommissioning effort was Russia. In Russia, RBMKs make up approximately 35% of the country's nuclear power, and are a significant source of heat energy and electricity for specific high priority and remote regions. As...

  11. Designing an experiment to study absorption vs. dose for feedback enabled radiation therapy

    Green, Hadrick Alexis
    In the field of radiation oncology, while there are simulations and devices that allow users to be relatively confident that radiation to the tumor and sparing of healthy tissue is being maximized, the inability to reliably measure and control the dose during radiation treatment is a major source of uncertainty. This uncertainty is due to issues such as organ movement, a lack of precise and constant knowledge of beam current at the target site, and the inability to correctly register dose during hardware or software failures; all of which result in radiation treatments being measured after the procedure or in...

  12. Investigation of velocity gradient as driving force of flow pulsation in fuel assemblies

    Everett, Patrick F
    The presence of quasi-periodic flow pulsations in fuel assemblies has been observed since the 1960's but is still not fully understood. Current design and licensing practices for nuclear reactor fuel mostly rely on 1-dimensional subchannel simulation tools, which might not accurately predict the increased subchannel mixing caused by flow pulsations. The present work develops a quantitative relationship between subchannel mixing and the inter-subchannel velocity gradient, shown to be the driving force of flow pulsation. A sensitivity study on rod-bundle geometry, based on an experiment by Bardet and Balaras at George Washington University, was conducted with a URANS method in transient...

  13. North Korea's nuclear weapons : interpreting weapon design progress based on nuclear test data

    Kenausis, Luisa R
    The proliferation of nuclear weapons is a significant global security issue, and it is important to carefully study the nuclear weapons programs of states that are actively engaging in nuclear proliferation. In this thesis, I interpret the seismic and radionuclide data from North Korea's first two nuclear tests in 2006 and 2009, emphasizing the limitations of that data in reaching deterministic conclusions about the precise devices tested by North Korea. I also review the seismological and radiological literatures surrounding a proposed North Korean nuclear test in May 2010, and summarize the process by which that proposal was investigated and rejected....

  14. Using molecular dynamics simulations to quantify the energy stored in irradiation defects in tungsten and aluminum

    Lowder, Sean
    Radiation damage in materials can create potentially catastrophic effects by causing failure in critical reactor components. In order to prevent such failures, it is imperative that this damage is understood and quantified. Currently, displacements-per-atom (DPA) is the most common form of expressing the amount of radiation a material has received. With its limitations on accurately expressing how much damage remains in a material post-irradiation, the DPA does not provide enough information about an exposed material to fully understand how it is has been compromised. One suggested replacement for the DPA is the Wigner stored energy, which is a measurement of...

  15. Experimental evaluation of polychromatic neutron diffraction

    Morrell, Jonathan T
    Neutron diffraction is a technique that allows scientists to measure the arrangement and motions of atoms in a crystalline lattice by observing neutrons scattering at angles that are characteristic of the interatomic distances of the crystal. This is useful for studying the response of crystals to stress, irradiation, or for observing their phases. This thesis implements and analyzes a technique known as polychromatic neutron powder diffraction, which has the potential to be used by an instrument to make many simultaneous neutron diffraction measurements. In this experiment, powder diffraction patterns were measured with a diffractometer in polychromatic mode, using both angle-dispersive...

  16. Impact of x-ray dose on the response of CR-39 nuclear track detector to 1-5.5 MeV alphas and 0.5-9.1 MeV protons for spectroscopy at the OMEGA Laser Facility and the National Ignition Facility

    Rojas, Jimmy A. (Rojas Herrera)
    The CR-39 nuclear track detector is used in many nuclear diagnostics fielded at inertial confinement fusion (ICF) facilities. Large x-ray fluences generated by ICF experiments may impact the CR-39 response to incident charged particles. To determine the impact of x-ray exposure on the CR-39 response to protons and alpha particles, a thick-target bremsstrahlung x-ray generator was used to expose CR-39 to various doses of 30 and 8keV Cu-K[alpha] and K[beta] x-rays. The CR-39 detectors were then exposed to 1-5.5 MeV alphas or 0.5- 9.1 MeV protons. The regions of the CR-39 exposed to x-rays showed a smaller track diameter than...

  17. Measurement of optical properties of molten salts and metallic compounds for advanced solar and nuclear systems

    Berdibek, Shapagat
    Renewable energies can reduce the dependence on fossil fuels. Solar thermal systems designed to use molten salts to directly absorb the solar heat are promising due to (1) potentially higher efficiency in capture of sunlight and (2) use of the salt to simultaneously capture sunlight and store heat in the salt. The optical properties of the molten salts are crucial for the design of such thermal systems because they determine the depth of the salt required to absorb sunlight and allow modeling of the performance of such systems. Molten salts are also being developed as coolants for high temperature reactors....

  18. Meta-analysis of Tokamak reactor designs

    Hernández, Manuel S. (Manuel Segundo)
    The long-term interest in nuclear fusion using tokamaks has yielded many published reactor designs. This study performs the first meta-analysis of tokamak reactor designs in an attempt to unveil new understanding not available in the traditional bottom-up method of looking at each design individually. Forty tokamak designs intended to produce significant fusion power at gains above one were identified in the published literature. Thirty-three important parameters describing a tokamak design were compiled by examining the set. The parameters from each design were extracted and placed into a database and plotted against each other to identify trends and outliers. Major outliers...

  19. Negotiation strategies in American-North Korean nuclear talks, 1992-2013

    Brandt-Erichsen, Haley
    North Korea's relationship with nuclear technology has concerned the world for decades. A wide array of negotiation methods from punitive sanctions to energy assistance have been attempted to dissuade the nation from developing its weapons program -- but every resolution has been temporary at best. We focus on the United States' negotiation strategy and attempt to uncover inconsistencies between it and the material facts of the North Korean situation. The historical record of past negotiations and rhetoric used by each party during previous attempts are considered in our analysis, in order to construct a picture of diplomatic evolution over time....

  20. Data processing and inference methods for zero knowledge nuclear disarmament

    DeMaio, William (William Aloysius)
    It is hoped that future nuclear arms control treaties will call for the dismantlement of stored nuclear warheads. To make the authenticated decommissioning of nuclear weapons agreeable, methods must be developed to validate the structure and composition of nuclear warheads without it being possible to gain knowledge about these attributes. Nuclear resonance fluorescence (NRF) imaging potentially enables the physically-encrypted verification of nuclear weapons in a manner that would meet treaty requirements. This thesis examines the physics behind NRF, develops tools for processing resonance data, establishes methodologies for simulating information gain during warhead verification, and tests potential inference processes. The influence...

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