Physics Commons^™

Separation Of Technetium From Uranium And Waste Form Synthesis, Kenneth Czerwinski

Waste Forms Campaign (TRP)

In this project, systematic investigations on the Tc-Zr binary metal system will be evaluated for the first time. The synthesis of metallic Tc as well as its alloys with Zr will be evaluated. In order to provide valuable data to AFC R&D, the thermodynamic equilibrium phases, as well as their performance under repository conditions, will be examined.

The research objectives of this project are as follows:

• Evaluate anion exchange methods for achieving the separation of Tc from U.

• Synthesize metallic Tc from the separated product.

• Synthesize and characterize Tc alloys.

• Investigate Tc-corrosion and Tc-leaching of binary …

Dissolution, Reactor, And Environmental Behavior Of Zro2-Mgo Inert Fuel Matrix, Kenneth Czerwinski

Fuels Campaign (TRP)

This project will examine inert fuels containing ZrO₂ and MgO as the inert matrix. Ceramics with this inert matrix, Ce, U and eventually Pu will be synthesized and examined. While the Advanced Fuel Cycle Initiative focus is on inert fuels with Pu as the fissile component, this task will perform initial laboratory experiments with Ce and U. The initial work with Ce will be performed early in the project with results used as a basis for U studies. Reactor physics calculations will be used to examine suitable quantities of burnable poisons from the candidate elements Gd, Er, or Hf. …

Impact Of The Synthesis Process On Structure Properties For Afci Fuel Candidates, Kenneth Czerwinski

Fuels Campaign (TRP)

The research objectives are:

• To explore a low-temperature fluoride route to synthesize actinide nitrides. • To characterize actinide nitrides structurally and thermally.

• To use high resolution TEM techniques to explore the microstructure of the radioactive samples.

Solution-Based Synthesis Of Nitride Fuels, Kenneth Czerwinski, Tyler A. Sullens

Fuels Campaign (TRP)

One of the original synthetic routes devised for the synthesis of U (III)N involved the entire reaction taking place in liquid ammonia. Several experimental reactions were conducted in an attempt to synthesize the UI₃(NH₃)_x and U(NH₂)₃(NH₃)_x precursors of U(III) N. Each attempt involved cleaning of the uranium metal to remove the oxide coating of the metal reagent with 3 washes of concentrated nitric acid, each followed by a rinse with liquid ammonia. Success of this cleaning procedure was varied, with a majority of cleaned metal oxidizing rapidly once …

University Of Nevada, Las Vegas Transmutation Research Program Annual Progress Report Academic Year 2007-2008, Anthony Hechanova, Rebecca Paulson

Transmutation Research Program Reports (TRP)

It is my pleasure to present the UNLV Transmutation Research Program’s seventh annual report that highlights the academic year 2007-2008. Supporting this document are the many technical reports and theses that have been generated over the past seven years.

In the seventh year of our program, we continued to see growth in the Radiochemistry Ph.D. program with a total of 20 students in the fourth year of the program (we anticipated twelve in the program proposal). Since our inception, the program has sponsored to their conclusion 48 M.S. and 6 Ph.D. degrees. The program supported 53 graduate students, 11 undergraduates, …

Photofragmentation Of Sif4 Upon Si 2p And F 1s Core Excitation: Cation And Anion Yield Spectroscopy, Maria Novella Piancastelli, Wayne C. Stolte, Renaud Guillemin, A. Wolska, Dennis W. Lindle

Chemistry and Biochemistry Faculty Research

We have studied the fragmentation dynamics of core-excited SiF₄ by means of soft-x-ray photoexcitation and partial positive and negative ion yield measurements around the Si L_2,3-shell and F K-shell ionization thresholds. All detectable ionic fragments are reported and we observe significant differences between the various partial ion yields near the Si 2p threshold. The differences are similar to our previous results from CH₃Cl showing more extended fragmentation in correspondence to transitions to Rydberg states. At variance with smaller systems, we observe negative ion production in the shape resonance region. This can be related …

Gnep Quarterly Input – Unlv July 1 Through September 30, 2007, Harry Reid Center For Environmental Studies. Nuclear Science And Technology Division

Transmutation Research Program Reports (TRP)

Quarterly report highlighting research projects, activities and objectives of the Transmutation Research Program at the Nuclear Science & Technology Division, Harry Reid Research Center.

The University of Nevada, Las Vegas supports the Global Nuclear Energy Partnership (GNEP) through research and development of technologies for economic and environmentally sound refinement of spent nuclear fuel. The UNLV program has four components: infrastructure, international collaboration, student-based research, and management and program support.

Afci Quarterly Input – Unlv April 1 Through June 30, 2007, Harry Reid Center For Environmental Studies. Nuclear Science And Technology Division

Transmutation Research Program Reports (TRP)

Quarterly report highlighting research projects, activities and objectives of the Transmutation Research Program at the Nuclear Science & Technology Division, Harry Reid Research Center.

The University of Nevada, Las Vegas supports the AFCI through research and development of technologies for economic and environmentally sound refinement of spent nuclear fuel. The UNLV program has four components: infrastructure, international collaboration, student-based research, and management and program support.

Afci Quarterly Input – Unlv January 1 Through March 31, 2007, Harry Reid Center For Environmental Studies. Nuclear Science And Technology Division

Transmutation Research Program Reports (TRP)

Quarterly report highlighting research projects, activities and objectives of the Transmutation Research Program at the Nuclear Science & Technology Division, Harry Reid Research Center.

The University of Nevada, Las Vegas supports the AFCI through research and development of technologies for economic and environmentally sound refinement of spent nuclear fuel. The UNLV program has four components: infrastructure, international collaboration, student-based research, and management and program support.

Fragmentation Of Methyl Chloride Studied By Partial Positive And Negative Ion Yield Spectroscopy, D. Ceolin, Maria Novella Piancastelli, Renaud Guillemin, Wayne C. Stolte, S-W Yu, Oliver Hemmers, Dennis W. Lindle

Environmental Studies Faculty Publications

The authors present partial-ion-yield experiments on the methyl chloride molecule excited in the vicinity of the Cl2p and C1s inner shells. A large number of fragments, cations produced by dissociation or recombination processes, as well as anionic species, have been detected. Although the spectra exhibit different intensity distributions depending on the core-excited atom, general observations include strong site-selective fragmentation along the C–Cl bond axis and a strong intensity dependence of transitions involving Rydberg series on fragment size.

Evaluation Of Cs/Sr Waste Form For Long Term Storage And Disposal, Gary Cerefice, Longzhou Ma

Waste Forms Campaign (TRP)

The goal of this project is to examine two potential concerns regarding the long-term performance of a proposed cesium/ strontium waste form. To facilitate long-term storage, up to 300 years, the disposal containers will need to be able to survive for the entire storage interval. The first aspect of the project will explore the potential interaction of the aluminosilicate waste form with the storage canister materials to determine if there is any corrosion or chemical interaction concerns for the storage of the materials.

At the end of the storage interval, most of the 137Cs in the waste form will have …

Investigation Of Optical Spectroscopy Techniques For On-Line Materials Accountability In The Solvent Extraction Process, Gary Cerefice, Kenneth Czerwinski

Safeguards Campaign (TRP)

The goal of this project is to evaluate the application of these analytical techniques to the on-line, real-time measurement of the actinide elements in the process streams of a solvent extraction process, with particular attention to the UREX+ and PUREX processes. Based on the experience gained through this effort, engineers will have the information necessary to decide if these technologies should be advanced to the prototype stage and tested at the pilot plant level. Through the experimental work planned as part of this effort, researchers will also develop a better understanding of the chemical interactions of the actinide elements, providing …

Dissolution, Reactor, And Environmental Behavior Of Zro2-Mgo Inert Fuel Matrix, Kenneth Czerwinski

Fuels Campaign (TRP)

This project will examine inert fuels containing ZrO₂ and MgO as the inert matrix. Ceramics with this inert matrix, Ce, U and eventually Pu will be synthesized and examined. While the Advanced Fuel Cycle Initiative focus is on inert fuels with Pu as the fissile component, this task will perform initial laboratory experiments with Ce and U. The initial work with Ce will be performed early in the project with results used as a basis for U studies. Reactor physics calculations will be used to examine suitable quantities of burnable poisons from the candidate elements Gd, Er, or Hf. …

University Of Nevada, Las Vegas Transmutation Research Program Annual Report Academic Year 2006-2007, Anthony Hechanova, Rebecca Arbour

Transmutation Research Program Reports (TRP)

It is my pleasure to present the UNLV Transmutation Research Program’s sixth annual report that highlights the academic year 2006-2007. Supporting this document are the many technical reports and theses that have been generated over the past five years.

In the sixth year of our program, we continued to see growth in the Radiochemistry Ph.D. program with a total of 13 students in the third year of the program (we anticipated eight in the program proposal). Since our inception, the program has sponsored to their conclusion 42 M.S. and 4 Ph.D. degrees. The program supported 39 graduate students, 17 undergraduates, …

Design And Performance Of A Curved-Crystal X-Ray Emission Spectrometer, A. C. Hudson, Wayne C. Stolte, Dennis W. Lindle, Renaud Guillemin

Chemistry and Biochemistry Faculty Research

A curved-crystal x-ray emission spectrometer has been designed and built to measure 2–5 keV x-ray fluorescence resulting from a core-level excitation of gas phase species. The spectrometer can rotate 180°, allowing detection of emitted x rays with variable polarization angles, and is capable of collecting spectra over a wide energy range (20 eV wide with 0.5 eV resolution at the Cl K edge) simultaneously. In addition, the entire experimental chamber can be rotated about the incident-radiation axis by nearly 360° while maintaining vacuum, permitting measurements of angular distributions of emitted x rays.

Afci Quarterly Input – Unlv July 1 Through September 30, 2006, Harry Reid Center For Environmental Studies. Nuclear Science And Technology Division

Transmutation Research Program Reports (TRP)

Quarterly report highlighting research projects, activities and objectives of the Transmutation Research Program at the Nuclear Science & Technology Division, Harry Reid Research Center.

The University of Nevada, Las Vegas supports the AFCI through research and development of technologies for economic and environmentally sound refinement of spent nuclear fuel. The UNLV program has four components: infrastructure, international collaboration, student-based research, and management and program support.

Low-Energy Nondipole Effects In Molecular Nitrogen Valence-Shell Photoionization, Oliver Hemmers, Renaud Guillemin, D. Rolles, A. Wolska, Dennis W. Lindle, E. P. Kanter, B. Krassig, S. H. Southworth, R. Wehlitz, B. Zimmermann, V. Mckoy, P. W. Langhoff

Environmental Studies Faculty Publications

Observations are reported for the first time of significant nondipole effects in the photoionization of the outer-valence orbitals of diatomic molecules. Measured nondipole angular-distribution parameters for the 3σ_g, 1π_u, and 2σ_u shells of N₂ exhibit spectral variations with incident photon energies from thresholds to ∼200  eV which are attributed via concomitant calculations to particular final-state symmetry waves arising from (E1)⊗(M1,E2) radiation-matter interactions first-order in photon momentum. Comparisons with previously reported K-edge studies in N₂ verify linear scaling with photon momentum, accounting in part for the significantly enhanced nondipole behavior observed in inner-shell ionization …

Femtosecond Nuclear Motion Of Hcl Probed By Resonant X-Ray Raman Scattering In The Cl 1s Region, Marc Simon, Loic Journel, Stephane Carniato, Richard Taieb, I. Minkov, Faris Gel'mukhanov, P. Salek, H. Agren, Renaud Guillemin, Wayne C. Stolte, A. C. Hudson, Dennis W. Lindle

Chemistry and Biochemistry Faculty Research

Femtosecond dynamics are observed by resonant x-ray Raman scattering (RXS) after excitation along the dissociative Cl 1s→6ơ* resonance of gas-phase HCl. The short core-hole lifetime results in a complete breakdown of the common nondispersive behavior of soft-x-ray transitions between parallel potentials. We evidence a general phenomenon of RXS in the hard-x-ray region: a complete quenching of vibrational broadening. This opens up a unique opportunity for superhigh resolution x-ray spectroscopy beyond vibrational and lifetime limitations.

Dissolution, Reactor, And Environmental Behavior Of Zro2-Mgo Inert Fuel Matrix, Kenneth Czerwinski

Fuels Campaign (TRP)

This project examines inert fuels containing ZrO₂ and MgO as the inert matrix, with the relative amount of MgO varied from 30% to 70% in ZrO₂. Reactor physics calculations are used to examine suitable quantities of burnable poisons from the candidate elements Gd, Er, or Hf with reactor grade Pu providing the fissile component, with up to 10% of ²³⁹Pu. Ceramics are synthesized and characterized based on the reactor physics results. The solubility of the fuel ceramics, in reactor conditions, reprocessing conditions, and repository conditions, are investigated in a manner to provide thermodynamic data necessary for …

Solution-Based Synthesis Of Nitride Fuels, Kenneth Czerwinski, Thomas Hartmann

Fuels Campaign (TRP)

A wide variety of fuel concepts are considered for advanced reactor technology including metals, metal oxides or metal nitrides as solid solutions or composite materials. Nitride fuels have appropriate properties for advanced fuels including high thermal conductivity, thermal stability, solid-state solubility of actinides, fissile metal density, and suitable neutronic properties. A drawback of nitride fuels involves their synthesis. A key parameter for preparing oxide fuels is the precipitation step in the sol-gel process. For nitride fuels, the current synthetic route is carbothermic reduction from the oxide to the nitride. This process step is based on solid phase reactions and for …

University Of Nevada, Las Vegas Transmutation Research Program Annual Report Academic Year 2005-2006, Anthony Hechanova, Rebecca Arbour

Transmutation Research Program Reports (TRP)

It is my pleasure to present the UNLV Transmutation Research Program’s fifth annual report that highlights the academic year 2005 – 2006. Supporting this document are the many technical reports and scientific papers that have been generated over the past five years.

In the fifth year of our program, we saw amazing growth in the Radiochemistry Ph.D. program with a total of 12 students in the second year of the program (twice the number we anticipated in the program proposal). In the back of this issue, under Infrastructure Augmentation, you will find some news about the new academic programs sponsored …

Afci Quarterly Input – Unlv July 1 Through September 30, 2005, Harry Reid Center For Environmental Studies. Nuclear Science And Technology Division

Transmutation Research Program Reports (TRP)

Quarterly report highlighting research projects, activities and objectives of the Transmutation Research Program at the Nuclear Science & Technology Division, Harry Reid Research Center.The University of Nevada, Las Vegas supports the AFCI through research and development of technologies for economic and environmentally sound refinement of spent nuclear fuel. The UNLV program has four components: infrastructure, international collaboration, student-based research, and management and program support.

Dissolution, Reactor, And Environmental Behavior Of Zro2-Mgo Inert Fuel Matrix: Neutronic Evaluation Of Zro2-Mgo Inert Fuels, E. Shwageraus, A. Galperin, E. Fridman, S. Kolesnikov

Fuels Campaign (TRP)

This report presents results of the analysis performed within the framework of “Dissolution, Reactor, and Environmental Behavior of ZrO₂-MgO Inert Fuel Matrix” project managed by University of Nevada at Las Vegas, Harry Reid Center for Environmental Studies. The main objective of the study was to explore the basic neutronic feasibility of using MgO-ZrO₂ as inert fuel matrix for Pu recycling in conventional Light Water Reactors (LWR).

Afci Quarterly Input – Unlv April Through June, 2005, Harry Reid Center For Environmental Studies. Nuclear Science And Technology Division

Transmutation Research Program Reports (TRP)

Quarterly report highlighting research projects, activities and objectives of the Transmutation Research Program at the Nuclear Science & Technology Division, Harry Reid Research Center.

The University of Nevada, Las Vegas supports the AFCI through research and development of technologies for economic and environmentally sound refinement of spent nuclear fuel. The UNLV program has four components: infrastructure, international collaboration, student-based research, and management and program support.

Dissolution, Reactor, And Environmental Behavior Of Zro2-Mgo Inert Fuel Matrix: Neutronic Evaluation Of Zro2-Mgo Inert Fuels, E. Fridman, S. Kolesnikov, E. Shwageraus, A. Galperin

Fuels Campaign (TRP)

This report presents the results of the Task 4, defined in working program as: evaluation of reactivity feedback coefficients. Three main parameters of the Fertile-Free Fuel (FFF) lattices were evaluated: Moderator Temperature Coefficient (MTC), Fuel Temperature Coefficient due to Doppler Effect (DC), and soluble Boron reactivity worth (BW).

One of the major design challenges associated with utilization of FFF is deterioration of the temperature coefficients and control materials reactivity worth caused by high thermal cross-section of Pu and consequent hardening of the neutron spectrum. The purpose of the investigation reported in this section is to estimate the potential of addition …

Dissolution, Reactor, And Environmental Behavior Of Zro2-Mgo Inert Fuel Matrix: Quarterly Report, January 2005 To March 2005, Earl Wolfram, Thomas Hartmann, Kenneth Czerwinski

Fuels Campaign (TRP)

This project will examine inert matrix fuels containing ZrO₂ and MgO as the inert matrix, with the relative amount of MgO varied from 30% to 70% in ZrO₂. Reactor physics calculations will be used to examine suitable quantities of burnable poisons from the candidate elements Gd, Er, or Hf with reactor grade Pu providing the fissile component, with up to 10% of ²³⁹Pu. Ceramics will be synthesized and characterized based on the reactor physics results. The solubility the fuel ceramics, in reactor conditions, reprocessing conditions, and repository conditions, will be investigated in a manner to provide …

Dissolution, Reactor, And Environmental Behavior Of Zro2-Mgo Inert Fuel Matrix: Neutronic Evaluation Of Zro2-Mgo Inert Fuels, E. Fridman, S. Kolesnikov, E. Shwageraus, A. Galperin

Fuels Campaign (TRP)

This report presents the results of the Task 3, defined in working program as: evaluation of burnable poison designs. Adopting the basic design of a standard PWR and Pu loadings required for 18-month cycle (results of Task 2), this part of the program is aimed to estimate performance of each BP design and BP material to address challenges of Fertile-Free Fuel (FFF) Concept. Finally, an optimal BP design will be developed and an overall feasibility of FFF concept will be determined. Basically, the main challenge encountered in neutronic design for a FFF core is to develop reactivity control system which …

Nuclear Criticality, Shielding, And Thermal Analyses Of Separations Processes For The Transmutation Fuel Cycle, William Culbreth, Denis Beller

Separations Campaign (TRP)

The first step in any transmutation strategy is the separation of radionuclides in used nuclear fuel. The current separation strategy supporting the Advanced Fuel Cycle Initiative (AFCI) program is based on the use of a solvent extraction separation process to separate the actinides, fission products, and uranium from used commercial nuclear fuel, and on the use of pyrochemical separation technologies to process used transmuter fuels. To separate the fission products and transuranic elements from the uranium in used fuel, the national program is developing a new solvent extraction process, the Uranium Extraction Plus, or UREX+, process based on the traditional …

Corrosion Of Steel By Lead Bismuth Eutectic, John Farley, Allen L. Johnson, Dale L. Perry

Transmutation Sciences Materials (TRP)

There is an active international interest in lead-bismuth eutectic and similar liquid lead systems because of the relevance to the transmutation of nuclear waste, fast reactors, and spallation neutron sources.

Materials in these systems must be able to tolerate high neutron fluxes, high temperatures, and chemical corrosion. For lead bismuth eutectic (LBE) systems, there is an additional challenge because the corrosive behaviors of materials in LBE are not well understood. Most of the available information on LBE systems has come from the Russians, who have over 80 reactor-years experience with LBE coolant in their Alpha-class submarine reactors. The Russians found …

Interaction Between Metal Fission Products And Triso Coating Materials: A Study Of Chemical Bonding And Interdiffusion: 1st Quarter Report, 2005, Clemens Heske

Fuels Campaign (TRP)

In this project we utilize a combination of state-of-the-art soft X-ray spectroscopies to understand the chemical bonding between metal fission products (Pd and Ag) with coating layers in TRISO fuel particles (SiC and pyrocarbon). We are primarily focusing on an analysis of intermediate chemical phases at the interface, the intermixing/diffusion behavior, and the electronic interface structure as a function of material choice (metal and coating materials), temperature, and external stress. In the current first project year, we are beginning these investigations with the Pd/SiC interface, as discussed in the previous two quarterly reports. Our first experiments (both using our lab …