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Nuclear Engineering Commons

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Full-Text Articles in Nuclear Engineering

An Ionization Chamber For High Resolution Fission Product Spectroscopy, James Cole Dec 2016

An Ionization Chamber For High Resolution Fission Product Spectroscopy, James Cole

Nuclear Engineering ETDs

The fission process has played a vital role in the world’s search for effective sources of alternative energy. With almost 80 years of work with fissionable material there is still much that is unknown about the process. Fission fragment mass and atomic number distributions are still lacking in completeness and critical detail. Knowledge of this information is highly sought after in the effort to improve various fields of nuclear physics and engineering such as reactor design, predictive models, waste disposal methods, and an overall understanding of the fission process. In an effort to better understand this process, we have ...


Doppler Temperature Coefficient Calculations Using Adjoint-Weighted Tallies And Continuous-Energy Cross Sections In Mcnp6, Matthew A. Gonzales Dec 2016

Doppler Temperature Coefficient Calculations Using Adjoint-Weighted Tallies And Continuous-Energy Cross Sections In Mcnp6, Matthew A. Gonzales

Nuclear Engineering ETDs

The calculation of the thermal neutron Doppler temperature reactivity feedback co- efficient, a key parameter in the design and safe operation of advanced reactors, using first order perturbation theory in continuous energy Monte Carlo codes is challenging as the continuous energy adjoint flux is not readily available. Traditional approaches of obtaining the adjoint flux attempt to invert the random walk process as well as require data corresponding to all temperatures and their respective tem- perature derivatives within the system in order to accurately calculate the Doppler temperature feedback.

A new method has been developed using adjoint-weighted tallies and On-The-Fly (OTF ...


Advanced Stochastic Collocation Methods For Polynomial Chaos In Raven, Paul W. Talbot Nov 2016

Advanced Stochastic Collocation Methods For Polynomial Chaos In Raven, Paul W. Talbot

Nuclear Engineering ETDs

As experiment complexity in fields such as nuclear engineering continually increases, so does the demand for robust computational methods to simulate them. In many simulations, input design parameters and intrinsic experiment properties are sources of uncertainty. Often small perturbations in uncertain parameters have significant impact on the experiment outcome. For instance, in nuclear fuel performance, small changes in fuel thermal conductivity can greatly affect maximum stress on the surrounding cladding. The difficulty quantifying input uncertainty impact in such systems has grown with the complexity of numerical models. Traditionally, uncertainty quantification has been approached using random sampling methods like Monte Carlo ...


Fokker-Planck-Based Acceleration For Sn Equations With Highly Forward Peaked Scattering In Slab Geometry, Japan K. Patel Nov 2016

Fokker-Planck-Based Acceleration For Sn Equations With Highly Forward Peaked Scattering In Slab Geometry, Japan K. Patel

Nuclear Engineering ETDs

Short mean free paths are characteristic of charged particles. High energy charged particles often have highly forward peaked scattering cross sections. Transport problems involving such charged particles are also highly optically thick. When problems simultaneously have forward peaked scattering and high optical thickness, their solution, using standard iterative methods, becomes very inefficient. In this dissertation, we explore Fokker-Planck-based acceleration for solving such problems.


Reduced-Order Monte Carlo Modeling Of Radiation Transport In Random Media, Aaron J. Olson Nov 2016

Reduced-Order Monte Carlo Modeling Of Radiation Transport In Random Media, Aaron J. Olson

Nuclear Engineering ETDs

The ability to perform radiation transport computations in stochastic media is essential for predictive capabilities in applications such as weather modeling, radiation shielding involving non-homogeneous materials, atmospheric radiation transport computations, and transport in plasma-air structures. Due to the random nature of such media, it is often not clear how to model or otherwise compute on many forms of stochastic media. Several approaches to evaluation of transport quantities for some stochastic media exist, though such approaches often either yield considerable error or are quite computationally expensive. We model stochastic media using the Karhunen-Loève (KL) expansion, seek to improve efficiency through use ...


Thin Film Alsb Carrier Transport Properties And Room Temperature Radiation Response, Erin Vaughan Jul 2016

Thin Film Alsb Carrier Transport Properties And Room Temperature Radiation Response, Erin Vaughan

Nuclear Engineering ETDs

Theoretical predictions for AlSb material properties have not been realized using bulk growth methods. This research was motivated by advances in molecular beam epitaxial (MBE) growth technology to produce high-quality thin-film AlSb for the purpose of evaluating transport properties and suitability for radiation detection. Simulations using MCNP5 were performed to benchmark an existing silicon surface barrier detector and to predict ideal AlSb detector behavior, with the finding that AlSb should have improved detection efficiency due to the larger atomic number of Sb compared with Si. GaSb diodes were fabricated by both homoepitaxial MBE and ion implantation methods in order to ...