Nuclear Engineering Commons^™

Pin-Wise Loading Optimization And Lattice–To-Core Coupling For Isotopic Management In Light Water Reactors, Hermilo Hernandez Noyola

Doctoral Dissertations

A generalized software capability has been developed for the pin-wise loading optimization of light water reactor (LWR) fuel lattices with the enhanced flexibility of control variables that characterize heterogeneous or blended target pins loaded with non-standard compositions, such as minor actinides (MAs). Furthermore, this study has developed the software coupling to evaluate the performance of optimized lattices outside their reflective boundary conditions and within the realistic three-dimensional core-wide environment of a LWR.

The illustration of the methodologies and software tools developed helps provide a deeper understanding of the behavior of optimized lattices within a full core environment. The practical applications …

Multivariate Optimization Of Neutron Detectors Through Modeling, Martin Rodney Williamson

Doctoral Dissertations

Due to the eminent shortage of 3He, there exists a significant need to develop a new (or optimize an existing) neutron detection system which would reduce the dependency on the current 3He-based detectors for Domestic Nuclear Detection Office (DNDO) applications. The purpose of this research is to develop a novel methodology for optimizing candidate neutron detector designs using multivariate statistical analysis of Monte Carlo radiation transport code (MCNPX) models. The developed methodology allows the simultaneous optimization of multiple detector parameters with respect to multiple response parameters which measure the overall performance of a candidate neutron detector. This is achieved by …

Multi-Modular Integral Pressurized Water Reactor Control And Operational Reconfiguration For A Flow Control Loop, Sergio Ricardo Pereira Perillo

Doctoral Dissertations

This dissertation focused on the IRIS design since this will likely be one of the designs of choice for future deployment in the U.S and developing countries. With a net 335 MWe output IRIS novel design falls in the “medium” size category and it is a potential candidate for the so called modular reactors, which may be appropriate for base load electricity generation, especially in regions with smaller electricity grids, but especially well suited for more specialized non-electrical energy applications such as district heating and process steam for desalination. The first objective of this dissertation is to evaluate and quantify …

Management Tool For Assessment Of Alternative Fuel Cycles, Jeffrey R. Preston

Doctoral Dissertations

A new approach to fuel cycle uncertainty analysis and optimization is presented that combines reactor physics information, spent fuel management, and economic forecasting, which may be used to investigate effects of decisions in the design of advanced nuclear fuel cycles. The Matlab-based simulation includes isotopic mass and integral decay heat data produced by reactor physics codes in the SCALE package (SAS2, ORIGEN-ARP, and ORIGEN-S). Reactor physics data for Light Water Reactor (LWR), and metal- and oxide-fueled Liquid Metal-cooled Fast Burner Reactor (LMFBR) designs are stored in databases that the code uses as needed. Detailed models of the once through and …

Boiling Water Reactor Core Simulation With Generalized Isotopic Inventory Tracking For Actinide Management, Jack Douglas Galloway

Doctoral Dissertations

The computational ability to accurately simulate boiling water reactor operation under the full range of standard steady-state operation, along with the capability to fully track the isotopic distribution of any fueled region in any location in the core has been developed. This new three-dimensional node-by-node capability can help designers track, for example, a full suite of minor and major actinides, fission products, and even light elements that result from depletion, decay, or transmutations. This isotopic tracking capability is not restricted to BWRs and can be employed in the modeling of PWRs, CANDUs, and other reactor types that can be modeled …

The Development Of A Parameterized Scatter Removal Algorithm For Nuclear Materials Identification System Imaging, Brandon Robert Grogan

Doctoral Dissertations

This dissertation presents a novel method for removing scattering effects from Nuclear Materials Identification System (NMIS) imaging. The NMIS uses fast neutron radiography to generate images of the internal structure of objects non-intrusively. If the correct attenuation through the object is measured, the positions and macroscopic cross-sections of features inside the object can be determined. The cross sections can then be used to identify the materials and a 3D map of the interior of the object can be reconstructed. Unfortunately, the measured attenuation values are always too low because scattered neutrons contribute to the unattenuated neutron signal. Previous efforts to …

Merging Data Sources To Predict Remaining Useful Life – An Automated Method To Identify Prognostic Parameters, Jamie Baalis Coble

Doctoral Dissertations

The ultimate goal of most prognostic systems is accurate prediction of the remaining useful life (RUL) of individual systems or components based on their use and performance. This class of prognostic algorithms is termed Degradation-Based, or Type III Prognostics. As equipment degrades, measured parameters of the system tend to change; these sensed measurements, or appropriate transformations thereof, may be used to characterize degradation. Traditionally, individual-based prognostic methods use a measure of degradation to make RUL estimates. Degradation measures may include sensed measurements, such as temperature or vibration level, or inferred measurements, such as model residuals or physics-based model predictions. Often, …

An Adaptive Nonparametric Modeling Technique For Expanded Condition Monitoring Of Processes, Matthew John Humberstone

Doctoral Dissertations

New reactor designs and the license extensions of the current reactors has created new condition monitoring challenges. A major challenge is the creation of a data-based model for a reactor that has never been built or operated and has no historical data. This is the motivation behind the creation of a hybrid modeling technique based on first principle models that adapts to include operating reactor data as it becomes available.

An Adaptive Non-Parametric Model (ANPM) was developed for adaptive monitoring of small to medium size reactors (SMR) but would be applicable to all designs. Ideally, an adaptive model should have …

Dead Time And Count Loss Determination For Radiation Detection Systems In High Count Rate Applications, Amol Patil

Doctoral Dissertations

"This research is focused on dead time and the subsequent count loss estimation in radiation detection systems. The dead time is the minimum amount of time required between two events to permit detection of those events individually by a radiation detection system. If events occur during the system dead time, they are lost. Such lost information can be important in many applications including high-precision spectroscopy, positron emission tomography (PET), and the scanning of spent nuclear fuel. Understanding of the behavior of radiation detection systems is important; thus this work included a comprehensive review of dead time and pulse pile-up models …