Nuclear Engineering Commons^™

Characterization Of Bending Fatigue Mini-Specimens For Nuclear Materials, Ahmed Suliman R. Haidyrah

Doctoral Dissertations

"New materials with superior radiation and corrosion resistance are needed to improve the economy and performance of current nuclear reactors as well as future nuclear reactors. Measurement of mechanical properties of the material of equipment is required to estimate its safe operating life. Studying fatigue of irradiated specimens is challenging due to space limitation in research reactors (e.g. ATR). The mini-specimen bending fatigue (Krouse-type) of nuclear materials was used to study fatigue properties and compare the obtained results with that of reference data of full size specimen. These Krouse-type were made of austenitic SS304, SS316, HT9 ferritic martensitic steel, and …

Iterative Ct Reconstruction From Few Projections For The Nondestructive Post Irradiation Examination Of Nuclear Fuel Assemblies, Muhammad Imran Khan Abir

Doctoral Dissertations

The core components (e.g. fuel assemblies, spacer grids, control rods) of the nuclear reactors encounter harsh environment due to high temperature, physical stress, and a tremendous level of radiation. The integrity of these elements is crucial for safe operation of the nuclear power plants. The Post Irradiation Examination (PIE) can reveal information about the integrity of the elements during normal operations and off‐normal events. Computed tomography (CT) is a tool for evaluating the structural integrity of elements non-destructively. CT requires many projections to be acquired from different view angles after which a mathematical algorithm is adopted for reconstruction. Obtaining many …

การดัดแปรพื้นผิวของผ้าไหมไทยด้วยพลาสมาคลื่นความถี่วิทยุร่วมกับไคโตซานสำหรับการต้านแบคทีเรีย, ศรายุทธ เข็มเงิน

Chulalongkorn University Theses and Dissertations (Chula ETD)

ไคโตซานถูกดัดแปรขนาดโมเลกุลโดยการนำไปฉายรังสีแกมมาที่ปริมาณรังสีต่าง ๆ หลังจากนั้นจึงนำไปทำเป็นสารละลาย แล้วนำไปกราฟท์ (graft) ลงบนผ้าไหมไทยที่ผ่านการดัดแปรผิวด้วยกระบวนการพลาสมาคลื่นความถี่วิทยุในสภาวะที่เหมาะสมมาแล้ว จากการศึกษาพบว่าอัตราการยึดเกาะของไคโตซานบนผ้าไหม (degree of grafting) จะแปรผันตรงกับมวลโมเลกุลของไคโตซาน ซึ่งกำลังพลาสมาที่เหมาะสมจะอยู่ที่ 120 วัตต์ , ระยะเวลาในการดัดแปรผิวผ้าไหมด้วยพลาสมาที่เหมาะสมอยู่ที่ 4 นาที และจากการทดลองพบว่า ผ้าไหมที่ไม่ผ่านการดัดแปรผิวด้วยเทคนิคพลาสมาจะมีการกราฟต์ติดของไคโตซานบนผ้าโดยเฉลี่ยอยู่ที่ 18.78 % ซึ่งต่ำกว่าผ้าไหมที่ผ่านการดัดแปรผิวด้วยเทคนิคพลาสมาที่มีการกราฟต์ติดของไคโตซานบนผ้าโดยเฉลี่ยอยู่ที่ 19.18 % ทั้งนี้ยังพบว่าผ้าระบบที่ผ่านการดัดแปรผิวด้วยพลาสมาจะมีค่าร้อยละแห่งการหลุดออกของไคโตซานจากเส้นใยต่ำกว่าผ้าอีกระบบที่ไม่ผ่านการดัดแปรผิวด้วยพลาสมา และที่มากกว่านั้นคือ เราสามารถมั่นใจได้เกินกว่า 90% ว่าผ้าระบบที่ใช้พลาสมาในการดัดแปรผิวจะสามารถผ่านการซักไปได้ถึง 155 ครั้ง และ 93 ครั้ง สำหรับเชื้อ E.coli และ S.aureus ตามลำดับ จึงจะหมดประสิทธิภาพในการต้านแบคทีเรีย ในทำนองกลับกัน ผ้าระบบที่ไม่ได้ใช้พลาสมาในการดัดแปรผิว แค่ผ่านการซักไปเพียง 67 ครั้ง และ 48 ครั้ง สำหรับเชื้อ E.coli และ S.aureus ตามลำดับ ก็ทำให้หมดประสิทธิภาพในการต้านแบคทีเรียแล้ว จึงกล่าวได้ว่า การใช้กระบวนการทาง RF-Plasma ด้วยเงื่อนไขของสภาวะดังตามที่ทดลอง จะสามารถทำให้ไคโตซานกราฟท์ติดกับเส้นใยได้ดีขึ้นและยังทำให้ไคโตซานดำรงอยู่บนเส้นใยได้ยาวนานขึ้น ผ้าไหมจึงต้านแบคทีเรียได้ยาวนานกว่าเดิม นั่นคือสามารถใช้งานได้ในระยะยาว

Impact Of Configuration Variations On Small Modular Reactor Core Performance, William Kirby Compton

Masters Theses

"One of the most promising new reactor designs is the Small Modular Reactor (SMR). These reactors, which operate under 300 MWe, will help bring cheap and safe nuclear energy to remote and centralized locations alike. Their ease of construction, advanced passive safety features, and cost effectiveness make these reactors an intriguing option for the near future.

In the work presented here, a neutronics analysis of the Westinghouse SMR was performed. Westinghouse's SMR design is a scaled down version of their AP1000 plant and will produce about 225 MWe of power. Though the parameters of the reactor core will be modeled …

Computer Aided Detection Of Oral Lesions On Ct Images, Shaikat Mahmood Galib

Masters Theses

"Oral lesions are important findings on computed tomography images. They are difficult to detect on CT images because of low contrast, arbitrary orientation of objects, complicated topology and lack of clear lines indicating lesions. In this thesis, a fully automatic method to detect oral lesions from dental CT images is proposed to identify (1) Closed boundary lesions and (2) Bone deformation lesions. Two algorithms were developed to recognize these two types of lesions, which cover most of the lesion types that can be found on CT images. The results were validated using a dataset of 52 patients. Using non training …

Neutronic Analysis Of Light Water Small Modular Reactor With Flexible Fuel Configurations, Brendan Dsouza

Masters Theses

"The study was focused on the analysis of light water Small Modular Reactor (SMR) with flexible fuel configurations. The core design, based on the Westinghouse UO₂ SMR with less than 5% enrichment was developed using the Monte Carlo N-Particle (MCNP) code. Neutronics analyses of a reference core with UO₂ fuel was performed to characterize parameters such as the radial neutron flux profile, the maximum to average flux ratio, the reactivity coefficient and critical boron concentration at beginning of life; which confirmed good performance in comparison to a standard UO₂ based pressurized water reactor.

Using this uranium oxide …

Initial Fuel Possibilities For The Thorium Molten Salt Reactor, Dustin Gage Green

Masters Theses

"The Generation IV International Forum placed six reactors as priority for research and development to compensate for the world's increasing energy demands. Among the six were Molten Salt Reactors (MSRs). These reactors utilize the Th/²³³U fuel cycle using molten fluoride or chloride salts as coolants. MSRs also have the possibility to use other fissile fuels especially with the first fleet of reactors given the low amount of Uranium-233 available commercially.

With the possibility of diverting from using ²³³U initially, the research presented here will benchmark ²³³U as a main fuel for MSRs using the Thorium Molten …

Safety Culture Monitoring: A Management Approach For Assessing Nuclear Safety Culture Health Performance Utilizing Multiple-Criteria Decision Analysis, James Harold Warren Jr.

Engineering Management & Systems Engineering Theses & Dissertations

Nuclear power plants are among the most technologically complex of all energy facilities. This complexity reflects the precision needed in design, maintenance and operations to harness the energy of the atom safely, reliably and economically. Nuclear energy thus requires consistent, high levels of organizational performance by the highly skilled professionals who operate and maintain nuclear power plants (Nuclear Energy Institute [NEI], 2014, p. 1).

A key element for achieving consistent, high levels of performance in a nuclear organization is its safety culture. Nuclear safety culture is for an organization what character and personality is for an individual: a feature that …

Incorporating Public Perceptions Into The Selection Of A Nuclear Fuel Cycle, John M. Swanson

Theses and Dissertations

The final disposal location for used nuclear fuel in the U.S. remains unresolved. A major complication in resolving this issue has historically been the lack of public acceptance. This motivates the creation of a decision making model for selecting a nuclear fuel cycle in the U.S. that incorporates the preferences of the public. A model based on the Analytic Hierarchy Process (AHP) was created, tested, and shown to be problematic in incorporating public opinion into decision objectives. A new model based on Multi-Attribute Utility Theory (MAUT) has been created. This model contains the fundamental objectives for both technical and non-technical …

Observability-In-Depth: An Essential Complement To The Defense-In-Depth Safety Strategy In The Nuclear Industry, Francesca Favaro, Joseph Saleh

Faculty Publications

Defense-in-depth is a fundamental safety principle for the design and operation of nuclear power plants. Despite its general appeal, defense-in-depth is not without its drawbacks, which include its potential for concealing the occurrence of hazardous states in a system, and more generally rendering the latter more opaque for its operators and managers, thus resulting in safety blind spots. This in turn translates into a shrinking of the time window available for operators to identify an unfolding hazardous condition or situation and intervene to abate it. To prevent this drawback from materializing, we propose in this work a novel safety principle …

Novel Deployment Of Elpasolites As A Dual Neutron / Gamma-Ray Directional Detector, Amber Lynn Guckes

UNLV Theses, Dissertations, Professional Papers, and Capstones

At a time when upholding national security has never been more important, there exists a need for the advancement of radiation detection technologies. Neutron and photon detectors are essential to fulfilling mission areas including detection and localization of missing, stolen or smuggled radiological or nuclear materials, quantification of the effects of a radiological or nuclear event, and supporting nonproliferation efforts. The aim of this study was to evaluate a new radiation detector based on the scintillation elpasolite compound Cs2LiYCl6:Ce (CLYC) for simultaneous measurements of neutron and photon flux and the localization of radiation sources. Previous studies performed on the CLYC …

Fast Fission Neutron Detection Using The Cherenkov Effect, Matthew Millard

All Theses

The Cherenkov effect in optically clear media of varying indices of refraction and composition was investigated for quantification of fast neutrons. The ultimate application of the proposed detection system is criticality monitoring. The optically clear medium, composed of select target nuclei, was coupled to a photomultiplier tube. Neutron reaction products of the target nuclei contained within the optical medium emit beta particles and gamma rays that produce Cherenkov photons within the medium which can be detected. Assessed media include quartz (SiO2), sapphire (Al2O3), spinel (MgAl2O4), and zinc sulfide (ZnS), which were irradiated with un-moderated 252Cf. Monte Carlo N-Particle (MCNP) code …

Transformation Of Uranium In A Geological Environment, Derrell Hood

All Theses

Incorporation of uranium into iron oxide minerals is a promising mechanism for the environmental immobilization of U(VI). In this study, synthesized hematite was doped with uranium and analyzed with SEM-EDS, TEM, XRD, and ICP-MS. The results of this analysis strongly indicate uranium incorporation into the mineral, as well as the possible presence of a co-precipitated uranium mineral clarkeite. Preliminary results also shows an increase in the amount of uranium associated with the hematite particles as a function of mineral aging. Cyclic Voltammetry (CV) was used to induce and characterize electrochemical changes of uranium in the doped hematite system; these changes …

Crystallographic Changes In Lead Zirconate Titanate Due To Neutron Irradiation, Alexandra Henriques, Joseph T. Graham, Sheldon Landsberger, Jon F. Ihlefeld, Geoff L. Brennecka, Donald W. Brown, Jennifer S. Forrester, Jacob L. Jones

Nuclear Engineering and Radiation Science Faculty Research & Creative Works

Piezoelectric and ferroelectric materials are useful as the active element in non-destructive monitoring devices for high-radiation areas. Here, crystallographic structural refinement (i.e., the Rietveld method) is used to quantify the type and extent of structural changes in PbZr_0.5Ti_0.5O₃ after exposure to a 1 MeV equivalent neutron fluence of 1.7x10¹⁵ neutrons/cm². The results showa measurable decrease in the occupancy of Pb and O due to irradiation, with O vacancies in the tetragonal phase being created preferentially on one of the two O sites. The results demonstrate a method by which the …

Nuclear Thermal Propulsion, Adam Dziubanek

Von Braun Symposium Student Posters

No abstract provided.

Investigation And Modeling Of Uranium Polarization For The Electrorefining Of Scrap U-Mo Foils, Melissa Rose

Open Access Dissertations

A uranium molybdenum alloy fuel has been proposed to convert research and test reactors from highly enriched uranium to low enriched uranium to increase the proliferation resistance at such reactors. Pyroprocessing has been selected to recover uranium from the scrap produced in the manufacture of this novel fuel type. Electrorefining, the main separation process of pyroprocessing, is modeled through a novel approach using corrosion theory. To use corrosion theory, knowledge of uranium polarization and kinetic parameters such as Tafel constant, transfer coefficient and exchange current density are required. Uranium polarization was investigated at five temperatures and three scan rates in …

Experimental Study Of Droplet Capable Conductivity Probe, Yikuan Yan

Open Access Theses

This research focus on experimentally studying the performance of the newly designed Droplet Capable Conductivity Probe (DCCP). ^ A literature review is performed to illustrate the development of current two-fluid model and interfacial area transport equation. Previous conductivity probe instrumentation is also reviewed. The limitations of current conductivity probe design are described and the necessity of developing DCCP is illustrated. ^ The concept of DCCP-2 and DCCP-4 are introduced and experiments are performed to benchmark the capability of DCCP-4.

Hydrogen Loading System Development And Evaluation Of Tritiated Substrates To Optimize Performance In Tritium Based Betavoltaics, Thomas E. Adams

Open Access Dissertations

State-of-the-art hydrogen loading system onto thin metallic films based on differential pressure in calibrated chambers has been developed for conditions pressures and temperatures up to 69 bar and 500°C, respectively. Experiments on hydrogen loading on to palladium films of thickness 50 and 250 nm were conducted at pressure ranging from 0.2 bar to 10 bar at temperature 310°C. For first time film hydrogen loading was carried out at 1 bar and at room temperature which temperature. Beta flux exiting surface of metal tritide films has been modeled with MC-SET (Monte Carlo Simulation of Electron Trajectories in solids). Surface beta flux …

Developing Professional Skills In Stem Students: Data Information Literacy, Lisa Zilinski, Megan R. Sapp Nelson, Amy S. Van Epps

Libraries Faculty and Staff Scholarship and Research

Undergraduate STEM students are increasingly expected to have some data use skills upon graduation, whether they pursue post-graduate education or move into industry. This project was an initial foray into the application of data information literacy competencies to training undergraduate students to identify markers of data and information quality. The data consumer training appeared within two courses to help students evaluate data objects, including databases and datasets available on the Internet. The application of the Data Credibility Checklist provides a foundation for developing data reuse competencies. Based upon the initial presentation of the content, it became obvious that students need …

Investigation Of The Performance Of Different Types Of Zirconium Microstructures Under Extreme Irradiation Conditions, Eric M. Acosta, Osman J. El-Atwani

The Summer Undergraduate Research Fellowship (SURF) Symposium

The safe and continued operation of the US nuclear power plants requires improvement of the radiation resistant properties of materials used in nuclear reactors. Zirconium is a material of particular interest due to its use in fuel cladding. Studies performed on other materials have shown that grain boundaries can play a significant role on the radiation resistant properties of a material. Thus, the focus of our research is to investigate the performance of different zirconium microstructures under irradiation conditions similar to those in commercial nuclear reactors. Analysis of the surface morphology of zirconium both pre- and post-irradiation was conducted with …