Nuclear Commons^™

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 …

Lunar Occultation Observer: A Nuclear Astrophysics All-Sky Survey Mission Concept, Riley Freelove

Von Braun Symposium Student Posters

No abstract provided.

Source Normalization Constants For Ground Distributed Fallout Fields, Justin M. Smith

Theses and Dissertations

Five assumptions regarding a first order model developed to calculate dose rate at a detector above a fallout field are analyzed. The omission of scattering is relaxed by the method of successive scatters resulting in a build up factor of 1.1. The use of a single average photon energy to represent a fallout distribution is analyzed using the Oak Ridge National Laboratory Isotope Generator (ORIGEN) Fallout Analysis Tool. An average photon energy of 0.81MeV is calculated and shown to be an accurate approximation of the fallout field energy distribution. A Gaussian distribution is used to calculate the minimal impact of …

Development Of Dose Conversion Coefficients For Radionuclides Produced In Spallation Neutron Sources, Phillip W. Patton

Transmutation Sciences Physics (TRP)

A research consortium comprised of representatives from several universities and national laboratories will be established as part of this project to generate internal and external dose conversion coefficients for radionuclides produced in spallation neutron sources. Information obtained from this multi-year study will be used to support the siting and licensing of future accelerator-driven nuclear initiatives within the U.S. Department of Energy complex, including the Spallation Neutron Source (SNS) and Accelerator Production of Tritium (APT) projects. Determination of these coefficients will also fill data gaps for several hundred radionuclides that exist in Federal Guidance Report (FGR) No. 11 and in Publications …

Symposium Participants' Bios, Bern Porter

Bern Porter Occasional Symposium Series

Biographical information about presenters and participants of the Bern Porter Occasional Symposium Series: The Bomb, the National Security State and the Advanced Thinking of Bern Porter.

Symposium Program, Bern Porter

Bern Porter Occasional Symposium Series

Printed program of the Bern Porter Occasional Symposium Series: The Bomb, the National Security State and the Advanced Thinking of Bern Porter.

Symposium Flyer, Bern Porter

Bern Porter Occasional Symposium Series

Flyer advertising the Bern Porter Occasional Symposium Series: The Bomb, the National Security State and the Advanced Thinking of Bern Porter.

The Role Of Llnl's Fast Calibration Facility In Diagnosing Nif Fusion Plasmas, Joshua G. Thompson, Carey Scott, Greg V. Brown

STAR Program Research Presentations

The Fusion and Astrophysics (FAST) Calibration and Diagnostic Facility uses the original Electron Beam Ion Trap (EBIT-I) to profile x-ray filters that are used in the Dante Soft X-Ray Diagnostic at the National Ignition Facility (NIF). FAST has an advantage over any other facility not only for its high accuracy, but also for its proximity to NIF in the Lawrence Livermore National Laboratory (LLNL). This makes for highly accurate and near-instantaneous filter calibration turnover.

EBIT-I was first constructed to create, trap, and observe static highly charged ions (HCIs) and conduct experimental astrophysics (creating an x-ray spectroscopy catalogue of ions). To …

Laboratory Astrophysics: Using Ebit Measurements To Interpret High Resolution Spectra From Celestial Sources, Carey Scott, Joshua Thompson, N. Hell, Greg V. Brown

STAR Program Research Presentations

Astrophysicists use radiation to investigate the physics controlling a variety of celestial sources, including stellar atmospheres, black holes, and binary systems. By measuring the spectrum of the emitted radiation, astrophysicists can determine a source’s temperature and composition. Accurate atomic data are needed for reliably interpreting these spectra. Here we present an overview of how LLNL’s EBIT facility is used to put the atomic data on sound footing for use by the high energy astrophysics community.

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 …

Surrogate Measurement Of The 238Pu(N,F) Cross Section, J. J. Ressler, J. T. Burke, J. Escher, C. Angell, M. S. Basunia, C. W. Beausang, L. A. Bernstein, D. L. Bleuel, R. J. Casperson, B. L. Goldblum, J. Gostic, R. Hatarik, R. Henderson, R. O. Hughes, J. Munson, L. Phair, T. J. Ross, N. D. Scielzo, E. Swanberg, I. Thompson, M. Wiedeking

Physics Faculty Publications

The neutron-induced fission cross section of ²³⁸Pu was determined using the surrogate ratio method. The (n,f) cross section over an equivalent neutron energy range 5–20 MeV was deduced from inelastic α-induced fission reactions on ²³⁹Pu, with ²³⁵U(α,α′f) and ²³⁶U(α,α′f) used as references. These reference reactions reflect ²³⁴U(n,f) and ²³⁵U(n,f) yields, respectively. The deduced ²³⁸Pu(n,f) cross section agrees well with standard data libraries up to …

Extraction Chromatographic Studies Of Rutherfordium And Dubnium Homologs, Megan E. Bennett

UNLV Theses, Dissertations, Professional Papers, and Capstones

Studying the chemistry of transactinide elements does not only allow for these elements to be properly placed in the Periodic Table, but it also permits for the extrapolation of the electronic structure based upon the position of the element in the Periodic Table. In addition it enable for the assessment of the role that relativistic effects play in the chemical behavior of the heaviest elements. An improved understanding of the role of relativistic effects in chemistry of the heaviest elements allows for a better understanding of the fundamentals principles that govern the Periodic Table. In order to investigate the chemistry …

The Economics Of The Atomic Bomb: Cost And Utilization, Jonathan M. Davis Mr.

Senior Honors Theses

Few moments in human history can be compared to the culmination of events that brought the atomic bomb into creation.  It is incredible to contemplate that while a nation was fighting a two front war that spanned from Europe into the Pacific, that the United States was able to utilize the time, energy, brains, materials, manpower, and capital to complete a project in four years. That under any other circumstances would have taken greater than half a century to complete.

First, this thesis will discuss breakthroughs in research that led scientists to believe that the atomic weapons could be built, …

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 …

Oral Presentation: Next Generation Nuclear Fuels, Douglas Hanks

Festival of Communities: UG Symposium (Posters)

Zirconium carbide has been proposed as a coating layer for next generation (“TRISO”) nuclear fuel, and is intended as a diffusion barrier to contain fission products (e.g., Pd). To study the chemical interaction between Pd and ZrC, their interface was investigated using X-ray Photoelectron Spectroscopy (XPS). Pd was step-wise deposited onto ZrC in ultra-high vacuum, and the chemical interaction at the interface was monitored, also as a function of temperature (up to 1000 C). In the presentation, details of the chemical interaction and changes in the chemical environment of Pd and their relevance for TRISO fuel will be discussed.

The Atomic Testing Museum, Las Vegas, Nevada, Angela Moor

Psi Sigma Siren

The Atomic Testing Museum attempts to interpret history that has barely ended. The controversy and emotion that surround nuclear weapons remain fresh in many Americans‘ minds. The museum must walk a careful line when interpreting such recent history. Few other American history museums offer interpretation of the Cold War, and certainly, the Atomic Testing Museum stands as the sole museum dedicated to atomic testing. As years go by, and the memory of the mushroom cloud floating on the Nevada desert fades, the museum may feel more comfortable in providing a balanced narrative on atomic testing. For now, as retired "Cold …

Triple Coincidence Beam Spin Asymmetry Measurements In Deeply Virtual Compton Scattering, Mustafa Canan

Physics Theses & Dissertations

The Generalized Parton Distributions (GPDs) provides hitherto the most complete information about the quark structure of hadron. GPDs are accessible through hard-exclusive reactions, among which Deeply Virtual Compton Scattering (DVCS) is the cleanest reaction. A dedicated DVCS experiment on Hydrogen (E00-110) ran in the Hall A at Jefferson Laboratory in Fall 2004. I present here Beam Spin Asymmetry (BSA) results for the ep → epγ reaction studied in the E00-110 experiment with fully exclusive triple coincidence H(e, e'γp ) detection. I present a re-calibration of the electromagnetic calorimeter used to detect the high energy photon. This calibration …

Background And Source Term Identification In Active Neutron Interrogation Methods, David A. Anthony

Theses and Dissertations

The detection and tracking of special nuclear material (SNM) is vitally important in order to know where these materials are and prevent them from being used in a harmful manner. Active neutron interrogation is a sought after method for this since the resulting high energy gamma rays produced by inelastic scattering and neutron capture reactions can pass through denser shielding than natural decay gammas, and their energy spectra are unique to each isotope. Using Monte Carlo N Particle (MCNP) simulations, this research investigated the characterization of gamma ray sources created by active neutron interrogation. Ring detector and mesh tallies within …

Characterization Of A Boron Carbide Heterojunction Neutron Detector, James E. Bevins

Theses and Dissertations

New methods for neutron detection have become an important area of research in support of national security objectives. In support of this effort, p-type B₅C on n-type Si heterojunction diodes have been built and tested. This research sought to optimize the boron carbide (BC) diode by coupling the nuclear physics modeling capability of GEANT4 and TRIM with the semiconductor device simulation tools. Through an iterative modeling process of controllable parameters, optimal device construction was determined such detection efficiency and charge collection were optimized. This allows an estimation of expected charge collection and efficiency given a set of operating …

Combined Effects Of Radio Frequency And Electron Radiation On Cmos Inverters, Kristofer R. Dahl

Theses and Dissertations

This research examines the measurement methodology, and the results of, the combined effects of electron and radio frequency irradiation (500kHz) on a CMOS Hex Inverter, CD4069UB. There have been many studies in recent years on the effects of electron radiation and electromagnetic interference on integrated circuits, however the combined effects have not been measured. A major obstacle for in-situ electron irradiation experiments is the over current hazard that exists to measurement equipment that comes from taking real-time, in-situ measurements. To overcome this, a test circuit was designed and built to allow for real-time in-situ measurement of the output voltage, current …