Nuclear Commons^™

The Utility Of Table-Top Exercises In Teaching Nuclear Security, Christopher Hobbs, Luca Lentini, Matthew Moran

International Journal of Nuclear Security

In the emerging field of nuclear security, those responsible for education and training are constantly seeking to identify and engage with tools and approaches that provide for a constructive learning environment. In this context, this paper explores the nature and value of Tabletop exercises (TTX) and how they can be applied in the nuclear security context. On the one hand, the paper dissects the key components of the TTX and considers the broader pedagogical benefits of this teaching method. On the other hand, the paper draws lessons from the authors’ experience of running TTXs as part of nuclear security professional …

Verifying The Implementation Of An Anisotropic Grain Boundary Energy Model In Idaho National Lab’S Marmot, John-Michael H. Bradley, Evan D. Hansen, Jarin C. French, Yongfeng Zhang (Mentor)

Idaho Conference on Undergraduate Research

This work aims to verify the correct implementation of an anisotropic grain boundary (GB) energy model for face-centered cubic (FCC) and fluorite materials in Idaho National Laboratory’s phase field fuel performance code MARMOT. The model was recently implemented in MARMOT with the purpose of enabling higher fidelity simulations of UO₂ nuclear fuels. As part of verification, tests were performed to measure the energy dependence on misorientation of high symmetry GBs in an FCC metal (Cu). The energies of the [100], [110], and [111] twist boundaries result as predicted, as do the energies of the [111] symmetric tilt boundaries. However, …

Neutron-Gamma Discrimination In Elpasolite Scintillator Detector, Brittany Morgan

UNLV Theses, Dissertations, Professional Papers, and Capstones

Existing nuclear stockpiles and weapons-making capabilities imperil the global community. Current nonproliferation efforts involve the research and development of newer, more efficient detection systems that can be deployed for the interdiction and monitoring of special nuclear materials (SNM). Spontaneous and induced fission events in SNM produce neutrons and gamma rays, which can be detected and analyzed, in particular, using scintillator detectors. Various electronic data acquisition systems and data analysis methods have been employed to record and characterize neutron and photon signatures. The goal of this thesis is to develop a new method of discrimination between neutrons and photons in the …

Mcnp6 Computational-Based Sensitivity Propagation Analysis Of Continuous Neutron Cross-Sections Using The Godiva (Hmf-001) And The Godiver (Hmf-004) Benchmark Criticality Study Cases, Lawrence James Lakeotes

UNLV Theses, Dissertations, Professional Papers, and Capstones

There has been a reduction in funding for theoretical and applied research for improving the nation's database of continuous neutron cross-sections at BNL-NNDC. From 1940 through the late 1980s, research and applied development produced volumes of reliable neutron continuous cross-sections for many isotopes. Currently, the cross-section work has been mainly computational. The focus of this research is mainly centered on the requirements for improving thermal cross-sections to support reactor operations and fuel storage. The research efforts will also helpfully aid in the fast fission spectrum in order to support fast reactor designs for improving safety analysis and feedback coefficients.

This …

Increasing 18f-Fdg Pet/Ct Capabilities In Radiotherapy For Lung And Esophageal Cancer Via Image Feature Analysis, Jasmine Alexandria Oliver

USF Tampa Graduate Theses and Dissertations

Positron Emission Tomography (PET) is an imaging modality that has become increasingly beneficial in Radiotherapy by improving treatment planning (1). PET reveals tumor volumes that are not well visualized on computed tomography CT or MRI, recognizes metastatic disease, and assesses radiotherapy treatment (1). It also reveals areas of the tumor that are more radiosensitive allowing for dose painting - a non-homogenous dose treatment across the tumor (1). However, PET is not without limitations. The quantitative unit of PET images, the Standardized Uptake Value (SUV), is affected by many factors such as reconstruction algorithm, patient weight, and tracer uptake time (2). …

Attenuation Properties Of Cement Composites: Experimental Measurements And Monte Carlo Calculations, Raul Florez

Masters Theses

"Developing new cement based materials with excellent mechanical and attenuation properties is critically important for both medical and nuclear power industries. Concrete continues to be the primary choice material for the shielding of gamma and neutron radiation in facilities such as nuclear reactors, nuclear waste repositories, spent nuclear fuel pools, heavy particle radiotherapy rooms, particles accelerators, among others. The purpose of this research was to manufacture cement pastes modified with magnetite and samarium oxide and evaluate the feasibility of utilizing them for shielding of gamma and neutron radiation. Two different experiments were conducted to accomplish these goals. In the first …

Voxel-Level Absorbed Dose Calculations With A Deterministic Grid-Based Boltzmann Solver For Nuclear Medicine And The Clinical Value Of Voxel-Level Calculations, Justin Mikell

Dissertations and Theses (Open Access)

Voxel-level absorbed dose (VLAD) is rarely calculated for nuclear medicine (NM) procedures involving unsealed sources or 90Y microspheres (YM). The current standard of practice for absorbed dose calculations in NM utilizes MIRD S-values, which 1) assume a uniform distribution in organs, 2) do not use patient specific geometry, and 3) lack a tumor model. VLADs overcome these limitations. One reason VLADs are not routinely performed is the difficulty in obtaining accurate absorbed doses in a clinically acceptable time. The deterministic grid-based Boltzmann solver (GBBS) was recently applied to radiation oncology where it was reported as fast and accurate for both …

Effect Of Helium Ions Energy On Molybdenum Surfaces Under Extreme Conditions, Joseph Fiala, Jitendra K. Tripathi, Sean Gonderman, Ahmed Hassanein

The Summer Undergraduate Research Fellowship (SURF) Symposium

Plasma facing components (PFCs) in fusion devices must be able to withstand high temperatures and erosion due to incident energetic ion radiations. Tungsten has become the material of choice for PFCs due to its high strength, thermal conductivity, and low erosion rate. However, its surface deteriorates significantly under helium ion irradiation in fusion-like conditions and forms nanoscopic fiber-like structures, or fuzz. Fuzz is brittle in nature and has relatively lower thermal conductivity than that of the bulk material. Small amounts of fuzz may lead to excessive contamination of the plasma, preventing the fusion reaction from taking place. Despite recent efforts, …

Design And Fabrication Of Liquid Scintillator Counter, Andrea Calderon Saucedo, John L. Orrell

STAR Program Research Presentations

Pacific Northwest National Laboratory (PNNL) is currently developing an ultra-low background liquid scintillator counter (ULB LSC) in the shallow underground laboratory. At a depth of 35-meters water-equivalent, the underground laboratory has a multi-layered shielding to keep out cosmic-ray induced background. The ULB LSC, which is located in a clean room facility, is a multi-layered design made up of various materials, including plastic scintillator veto panels, borated polyethylene, lead and copper. These layers help lower the contributions of the terrestrial background and intrinsic background, resulting from the impurities present in the materials, to the overall background count rate observed by the …

Student Writing Competition

International Journal of Nuclear Security

No abstract provided.

Cover

International Journal of Nuclear Security

No abstract provided.

Masthead

International Journal of Nuclear Security

No abstract provided.

From The Editor

International Journal of Nuclear Security

No abstract provided.

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 …

Doube-Pulse Laser-Induced Breakdown Spectroscopy Of Multi-Element Sample Containing Low- And High-Z Analytes, Patrick J. Skrodzki, Jason R. Becker, Prasoon K. Diwakar Ph. D., Sivanandan S. Harilal Ph. D., Ahmed Hassanein Ph. D.

The Summer Undergraduate Research Fellowship (SURF) Symposium

Laser-induced breakdown spectroscopy (LIBS) is a portable, remote, non-invasive analytical technique which effectively distinguishes neutral and ionic species for a range of low- to high-Z elements in a multi-element target. Subsequently, LIBS holds potential in special nuclear material (SNM) sensing and nuclear forensics requiring minimal sample preparation and detecting isotopic shifts which allows for differentiation in SNM (namely U) enrichment levels. Feasible applications include not only nonproliferation and homeland security but also nuclear fuel prospecting and industrial safeguard endorsement. Elements of higher mass with complex atomic structures, such as U, however, result in crowded emission spectra with LIBS, and characteristic …

Double-Pulse Nd:Yag-Co2 Libs Excitation For Bulk And Trace Analytes, Jason R. Becker, Patrick Skrodzki, Prasoon Diwakar, Sivanandan Harilal, Ahmed Hassanein

The Summer Undergraduate Research Fellowship (SURF) Symposium

Laser-induced breakdown spectroscopy [LIBS] is a commonly used technique for multi-element analyses for various applications such as space exploration, nuclear forensics, environmental analysis, process monitoring. The advantages of the LIBS technique include robustness, ease of use, field portability, and real-time, non-invasive multi-element analyses. However, in comparison to other lab based analytical techniques, it suffers from low precision and low sensitivity. In order to overcome these drawbacks, various approaches have been used, including double-pulse LIBS [DPLIBS]. Typically, various wavelength combinations of two Nd: yttrium aluminum garnet [YAG] lasers have been used for DPLIBS. However, the use of long wavelength (CO_{2 …}

Time Correlated Measurements Using Plastic Scintillators With Neutron-Photon Pulse Shape Discrimination, Norman Edison Richardson

UNLV Theses, Dissertations, Professional Papers, and Capstones

Since the beginning of the nuclear age, there has been a strong demand for the development of efficient technologies for the detection of ionizing radiation. According to the United States' Department of Energy, the accurate assessment of fissile materials is essential in achieving the nonproliferation goals of enhancing safety and security of nuclear fuel cycle and nuclear energy facilities [1]. Nuclear materials can be characterized by the measurement of prompt and delayed neutrons and gamma rays emitted in spontaneous or induced fission reactions [2] and neutrons emitted in fission reactions are the distinctive signatures of nuclear materials. Today, the most …

Criticality And Characteristic Neutronic Analysis Of A Transient-State Shockwave In A Pulsed Spherical Gaseous Uranium-Hexafluoride Reactor, Jeremiah Boles

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of this study is to analyze the theoretical criticality of a spherical uranium-hexafluoride reactor with a transient, pulsed shockwave emanating from the center of the sphere in an outward-radial direction. This novel nuclear reactor design, based upon pulsed fission in a spherical enclosure is proposed for possible use in direct energy conversion, where the energy from fission products is captured through the use of electrostatic fields or through induction. An analysis of the dynamic behavior of the shockwave in this reactor is the subject of this thesis. As a shockwave travels through a fluid medium, the characteristics of …

Novel Production Techniques Of Radioisotopes Using Electron Accelerators, Daniel Robert Lowe

UNLV Theses, Dissertations, Professional Papers, and Capstones

Non-traditional radioisotope production techniques using a compact, high power linear electron accelerator have been demonstrated and characterized for the production of 18F, 47Sc, 147Pm, and 99mTc from a variety of target candidates. These isotopes are used extensively in the medical field as diagnostic and therapy radioisotopes, as well as the space industry as RTG's. Primary focus was placed on 99mTc as it constitutes approximately 80% of all diagnostic procedures in the medical community that use radioactive tracers. It was also the prime focus due to recent events at the Chalk River nuclear reactor, which caused global shortages of this isotope …

Development Of Tungsten Based Ceramic-Metallic Nuclear Fuel Containing Uranium Oxide For Nuclear Cryogenic Propulsion Stage Project, Jaewon Choi

Von Braun Symposium Student Posters

No abstract provided.

Analysis Of Stacked Linear Transformer Drivers For Application In Nuclear Fusion Propulsion, Patrick Giddens

Von Braun Symposium Student Posters

No abstract provided.

An Extension To Particle Polarizability To Predict Coupling Behavior In Periodic Nanoplasmonic Arrays, Drew Dejarnette

Graduate Theses and Dissertations

Plasmonic nanoparticles organized in arrays interact to create spectral patterns which are amplified by individual particle polarizability. It was hypothesized that particle polarizability could be used as a predictor of spectral behavior from far-field interactions within the array. Inter-particle coupling produced an extraordinary peak in extinction efficiency at wavelengths equal to or larger than the single particle plasmon resonance peak. Interactions that produced constructive coupling were found to mimic changes in the particle polarizability model. Testing of the hypothesis was performed using the coupled dipole approximation with parametric characterization of array geometries, giving specific particle size and lattice constant combinations …

Spectroscopic Methods Of Process Monitoring For Safeguards Of Used Nuclear Fuel Separations, Jamie Lee Warburton

UNLV Theses, Dissertations, Professional Papers, and Capstones

To support the demonstration of a more proliferation-resistant nuclear fuel processing plant, techniques and instrumentation to allow the real-time, online determination of special nuclear material concentrations in-process must be developed. An ideal materials accountability technique for proliferation resistance should provide nondestructive, realtime, on-line information of metal and ligand concentrations in separations streams without perturbing the process. UV-Visible spectroscopy can be adapted for this precise purpose in solvent extraction-based separations.

The primary goal of this project is to understand fundamental URanium EXtraction (UREX) and Plutonium-URanium EXtraction (PUREX) reprocessing chemistry and corresponding UV-Visible spectroscopy for application in process monitoring for safeguards. By …

A Modular Design For Nuclear Battery Technology, Randy Lao

Physics

This paper is an exploration of the physics and technology behind the development and on-going research of nuclear batteries. This includes the topics of isotope radiation suitable for such a device as well as the components necessary to utilize the energy of natural decay, such as solid and liquid semiconductors. Most importantly for public use, the battery requires a safe containment system while allowing convenient modularity. An efficiency and total output comparison will be made with standard button cell and dry cell batteries. Also, a proposal is made for the design of an enclosure to contain radioactive materials. The safe …

Structure Studies On Lanthanide Technetium Pyrochlores As Prospective Host Phases To Immobilize 99- Technetium And Fission Lanthanides From Effluents Of Reprocessed Used Nuclear Fuels, Thomas Hartmann, Ariana Alaniz

Festival of Communities: UG Symposium (Posters)

We performed a systematic investigation of the incorporation of 99Tc into pyrochlore oxide structures, Ln2Tc2O7, where Ln represents trivalent lanthanide Ln3+ cations, while 99Tc is atetravalent, Tc4+, metal cation. Pyrochlore compounds are high-melting temperature oxides and are recognized for their durability. Our goal in this preliminary study is to characterize and quantify the range of stability of the lanthanum technetium pyrochlore oxide phase. Hereby, powder X-ray diffraction (XRD) and Rietveld analysis were used to determine and characterize the crystalline phase content with high accuracy, and scanning electron microscopy (SEM) was used to characterize the microstructure and homogeneity of the synthesized …

Scaling Properties At Freeze-Out In Relativistic Heavy-Ion Collisions, M. M. Aggarwal, Z. Ahammed, A. V. Alakhverdyants, I. Alekseev, J. Alford, B. D. Anderson, S. Bueltmann, I. Koralt, D. Plyku, Star Collaboration

Physics Faculty Publications

Identified charged pion, kaon, and proton spectra are used to explore the system size dependence of bulk freeze-out properties in Cu+Cu collisions at √sNN=200 and 62.4 GeV. The data are studied with hydrodynamically motivated blast-wave and statistical model frameworks in order to characterize the freeze-out properties of the system. The dependence of freeze-out parameters on beam energy and collision centrality is discussed. Using the existing results from Au + Au and pp collisions, the dependence of freeze-out parameters on the system size is also explored. This multidimensional systematic study furthers our understanding of the QCD phase diagram revealing the importance …

Nuclear Electromagnetic Currents In Chiral Effective Field Theory, Saori Pastore

Physics Theses & Dissertations

A nucleon-nucleon potential and consistent nuclear electromagnetic currents are derived in chiral effective field theory retaining pions and nucleons as explicit degrees of freedom. The calculation of the potential is carried out up to next-to-next-to leading order (N²LO), while the currents include up to N³LO corrections. The potential at N² LO and currents at N³LO consist of two-pion-exchange and contact contributions. The currents are then utilized to study a number of low-energy electromagnetic observables induced by magnetic dipole transitions, such as the deuteron and trinucleon magnetic moments and the np, nd and n …

Uncertainty Quantification Of Multi-Component Isotope-Separation Cascade Model, Khoi D. Tran

Theses and Dissertations

Monte Carlo uncertainty quantification (UQ) capability has been added to a code for modeling multi-component steady-state isotope-separation enrichment cascades to characterize the propagation of uncertainties in input data that define the cascade and the feed. Random samples of error for every computational input are drawn from its individual uncertainty distribution and added to the inputs, creating a set of enrichment cascade problems with perturbed inputs. The set of problems is solved using the verified code. The cascade outputs are then characterized using the empirical cumulative distribution. The uncertainty output data are analyzed to gain new insights into the behaviors of …

Evaluation Of Low-Temperature Fluoride Routes To Synthesize Actinide Nitrides And Oxide Solid Solutions, Gunanda Waduge Chinthaka Silva

UNLV Theses, Dissertations, Professional Papers, and Capstones

Actinide mononitrides have been considered as a possible nuclear fuel for the Generation-IV nuclear reactor systems. In the process of evaluating these actinide mononitrides as nuclear fuel, it is important to study different chemical and physical characteristics of these compounds. Synthesis of the materials is thus important. Carbothermic reduction is one of the techniques that have been used to synthesize actinide mononitrides. In this method, a mixture of actinide oxide such as UO ₂ and excess carbon is heat treated at temperatures greater than 1700 °C under a nitrogen atmosphere. The technique is however not promising in synthesizing the actinide …

The Potential Contribution Of Organic Salts To New Particle Growth, Kelley Barsanti, Peter H. Mcmurry, J. N. Smith

Civil and Environmental Engineering Faculty Publications and Presentations

Field and lab measurements suggest that low-molecular weight (MW) organic acids and bases exist in accumulation and nucleation mode particles, despite their relatively high pure-liquid vapor pressures. The mechanism(s) by which such compounds contribute to the mass growth of existing aerosol particles and newly formed particles has not been thoroughly explored. One mechanism by which low- MW compounds may contribute to new particle growth is through the formation of organic salts. In this paper we use thermodynamic modeling to explore the potential for organic salt formation by atmospherically relevant organic acids and bases for two system types: one in which …