Nuclear Engineering Commons^™

Calibration Of Ysz Sensors For The Measurement Of Oxygen Concentration In Liquid Pb-Bi Eutectic, Xiaolong Wu, Ramkumar Sivaraman, Ning Li, Wei Hang, T. W. Darling, Yingtao Jiang, Woosoon Yim, Bingmei Fu

Transmutation Sciences Materials (TRP)

Although liquid lead-bismuth eutectic (LBE) is a good candidate for coolant in the subcritical transmutation blanket, it is known to be corrosive to stainless steel, the material of the carrying tubes and containers. Such longterm corrosion problem can be prevented by producing and maintaining a protective oxide layer on the exposed surface of stainless steel. For this purpose, it is required to accurately control the concentration of oxygen dissolved in LBE. Currently, YSZ (Yttria Stabilized Zirconia) oxygen sensors, based on an existing automotive oxygen sensor, with molten bismuth saturated with oxygen as the reference, have been selected for oxygen-concentration measurement. …

Radiation Transport Modeling Using Parallel Computational Techniques, William Culbreth

Reactor Campaign (TRP)

The Advanced Fuel Cycle Initiative (AFCI) program will rely on the use of accurate calculations and simulations of criticality and shielding for the separation process of the longlived isotopes that present a significant safety hazard in commercial spent fuel. To help design and verify the safety of the separation process, the neutronics code MCNPX will be used to model the distribution of neutron flux within the fuel blanket and to determine the neutron multiplication, k_eff. However, the cross section libraries and computational methods used by MCNPX at these neutron energies still have some uncertainty and will require validation. …

University Of Nevada, Las Vegas Transmutation Research Program Annual Report 2002, Anthony Hechanova, Elizabeth Johnson, Gary Cerefice

Transmutation Research Program Reports (TRP)

The UNLV Transmutation Research Program consists of four components: Program Support, Research Infrastructure Augmentation, International Collaboration, and Student Research.

In the first year of the program, the student research component was supported by the infrastructure augmentation and the program support components. In the second year of the program, the fourth leg of the support system, international collaborations, was added to the research support system.

Modeling, Fabrication, And Optimization Of Niobium Cavities: Final Phase, Robert A. Schill Jr., Mohamed Trabia

Transmutation Sciences Materials (TRP)

Niobium cavities are important parts of the integrated NC/SC high-power linacs. Over the years, researchers in several countries have tested various cavity shapes. They concluded that elliptically shaped cells are the most appropriate shape for superconducting cavities. The need for very clean surfaces lead to the use of a buffered chemical polishing produce for surface cleaning to get good performance of the cavities. This is the third and final phase of the study.

The first phase has resulted in improving the basic understanding of multipacting and the process of chemical etching. The second phase has resulted in an experimental setup …

Modeling, Fabrication, And Optimization Of Niobium Cavities, Robert A. Schill Jr., Mohamed Trabia, William Culbreth

Transmutation Sciences Materials (TRP)

One of the key technologies for the deployment of accelerator driven transmutation systems is the accelerator itself. To increase the efficiency of the high-power accelerators needed to support the transmutation mission, the national and international accelerator teams have proposed using elliptical superconducting niobium cavities. This project is tasked with examining the impacts of the design and fabrication technologies for these elliptical niobium cavities on their performance. Niobium was selected primarily due to its behavior at low temperatures.

One of the major sources of energy loss from a superconducting accelerator cavity is a process known as multiple impacting (or “multipacting”) of …

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

Transmutation Sciences Materials (TRP)

Materials for transmuter systems must be able to tolerate high neutron fluxes, great temperatures, and chemical corrosion. For lead bismuth eutectic (LBE) systems, there is an additional challenge in that 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 that the presence of small amounts of oxygen (on the order of parts per million) in the LBE significantly reduced corrosion. However, a fundamental understanding and verification of its …

Surface Studies Of Corrosion Of Stainless Steel By Lead Bismuth Eutectic, Daniel Koury, Brian D. Hosterman, John Farley, Dale L. Perry, D. Parsons, J. Manzerova, Allen L. Johnson

Transmutation Sciences Materials (TRP)

Why is Lead Bismuth Eutectic Important?

• Changing national security stances have led to reexamination of nuclear waste reprocessing

• Dangerous actinides can be separated and

• Transmuted into safer products, creating a waste form dangerous for only hundreds of years, in addition to the production (up to 1/3 of the original fission energy) of useful energy

• Non-moderating coolants or spallation targets for production of fast neutrons is required for transmutation

• Russian experience with LBE coolants in their nuclear submarine fleet makes LBE an attractive possible transmutation coolant technology

• Corrosion of steel by LBE is an important …

Environment-Induced Degradation And Crack-Growth Studies Of Candidate Target Materials, Ajit K. Roy, Brendan O'Toole, Zhiyong Wang, David W. Hatchett

Transmutation Sciences Materials (TRP)

The primary objective of this task is to evaluate the potential for the environmentally-assisted cracking of candidate target materials for applications in spallation-neutron-target systems, such as accelerator-driven system for the transmutation of waste. The materials selected for evaluation and characterization are martensitic stainless steels (SS) including Alloys HT- 9, EP 823 and Type 422 stainless steel.

More recently, this experimental program has been expanded to evaluate the effect of molten lead-bismuth eutectic (LBE) on the corrosion behavior of target materials in the presence of oxygen. Since the materials performance laboratory (MPL) at UNLV currently cannot accommodate this type of testing, …

Modeling Corrosion In Oxygen Controlled Lbe Systems With Coupling Of Chemical Kinetics And Hydrodynamics, Samir Moujaes, Yitung Chen

Transmutation Sciences Materials (TRP)

The corrosion of structural materials is a major concern for the use of lead-bismuth eutectic (LBE) systems for nuclear applications such as in transmuter targets or fast reactors. Corrosion in liquid metal systems can occur through various processes, including, for example, dissolution, formation of inter-metallic compounds at the interface, and penetration of liquid metal along grain boundaries. Predicting the rate of these processes depends on numerous system operational factors: temperature, system geometry, thermal gradients, solid and liquid compositions, and velocity of the liquid metal, to name a few. Corrosion, along with mechanical and/or hydraulic factors, often contributes to component failure. …

Modeling Of Corrosion In Oxygen Controlled Lead Bismuth Eutectic Systems With The Coupling Of Chemical Kinetics And Hydrodynamics, Samir Moujaes, Yitung Chen, Kanthi Kiran Dasika, Chao Wu

Transmutation Sciences Materials (TRP)

Objectives:

• To simulate a 2-D model of the Materials Test Loop by approximating it to be a toroid with a pie cross section for the purpose of comparing the simulated results with the analytical results.
• The temperature and concentration profiles on the wall boundaries imposed are similar to the actual test model.
• Geometry effects have great influence on local corrosion rate.
• A 2-D benchmark problem and a sudden expansion case are studied which show good consistency to analytical solution.
• Results from 2-D sudden expansion problem are similar to experimental data obtained by other researchers.

Development Of A Mechanistic Understanding Of High-Temperature Deformation Of Alloy Ep-823, Ajit K. Roy, Brendan O'Toole

Transmutation Sciences Materials (TRP)

The purpose of this task is to evaluate the mechanical properties of Alloy EP-823 at temperatures relevant to the transmutation processes. Testing has been initiated to evaluate the tensile properties of martensitic Alloy EP-823 stainless steel at temperatures ranging from ambient (25 °C) to 600°C. The test materials were thermally treated prior to the evaluation of their tensile properties. The deformation characteristics of these tensile specimens, upon completion of testing, will be evaluated by surface analytical techniques such as scanning electron microscopy (SEM) and transmission electron microscopy (TEM).

Developing A Sensing System For The Measurement Of Oxygen Concentration In Liquid Pb-Bi Eutectic, Yingtao Jiang, Bingmei Fu, Woosoon Yim

Transmutation Sciences Materials (TRP)

Lead-bismuth eutectic (LBE) is a candidate as a spallation target in sub-critical transmutation systems and as a coolant in nuclear programs. One of the primary concerns with LBE systems is the corrosion of stainless steel, the primary structural material used in nuclear systems. To mitigate this problem, trace levels of oxygen can be introduced into the system, causing the formation of a protective oxide layer at the interface between the LBE and steel. To protect the steel components, this oxide layer must be properly maintained. However, too much oxygen will produce unwanted oxide precipitation within the coolant and elsewhere in …

Use Of Positron Annihilation Spectroscopy For Stress-Strain Measurements, Ajit K. Roy

Transmutation Sciences Materials (TRP)

One of the greatest challenges in evaluating the performance of materials in the real world is the determination of residual stresses, or the stresses induced in a material. Plastic deformation of metals and alloys produces an increase in the number of lattice imperfections known as dislocations, which by virtue of their interaction results in higher state of internal stress and reduces ductility. These stresses, if not properly annealed (released) can significantly degrade the long-term performance of the materials.

Due to the high temperatures and radiation fields typically encountered in most nuclear systems, such as accelerator-driven transmutation systems (ADS) and nuclear …

Fundamental And Applied Experimental Investigations Of Corrosion Of Steel By Lbe Under Controlled Conditions: Kinetics, Chemistry, Morphology, And Surface Preparation, Allen L. Johnson, John Farley, Dale L. Perry

Transmutation Sciences Materials (TRP)

An innovative research program is proposed to investigate the corrosion of steel by lead alloys, and in particular lead-bismuth eutectic (LBE). In our previous work, some steels were found to be far more resistant to corrosion by LBE than others depending on surface preparation (cold working). This program would allow testing of crucial hypotheses about the causes of the observed increased corrosion resistance. We propose to build a new test facility at UNLV to expose steel samples to LBE as well as facilities to prepare steel samples as indicated by our work.

The unique capabilities of the test system will …

Neutron Multiplicity Measurements Of Target/Blanket Materials, Carter D. Hull, Denis Beller

Transmutation Sciences Physics (TRP)

To optimize the performance of accelerator driven transmutation systems (ADS), engineers will need to design the system to operate with a neutron multiplication factor just below that of a critical, or self-sustaining, system. This design criteria requires particle transport codes that instill the highest level of confidence with minimal uncertainty, because the larger the uncertainties in the codes, the larger the safety margin required in the design and the lower the efficiency of the ADS transmuter. For current design efforts, the MCNPX code is used to determine neutron production and transport for spallation neutron systems.

While providing a very useful …

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 …

Design And Analysis Of A Process For Melt Casting Metallic Fuel Pins Incorporating Volatile Actinides, Yitung Chen, Darrell Pepper, Randy Clarksean

Fuels Campaign (TRP)

The goal of this project is to investigate the casting processes for metallic fuels to help design a process that minimizes the loss of the volatile actinide elements from the fuel.

The research effort centers on the development of advanced numerical models to assess conditions that significantly impact the transport of volatile actinides during the melt casting process and represents a joint effort between researchers at the University of Nevada, Las Vegas (UNLV) and Argonne National Laboratory (ANL).

Design And Evaluation Of Processes For Fuel Fabrication, Georg F. Mauer

Fuels Campaign (TRP)

The goal of this research project is to provide technical support to process designers working on the development of the fuel cycles for transmutation applications. Detailed process models are developed to better define the impact of fuel choice on the transmuter fuel cycle, including relative process losses, waste generation, and plant capital cost. These process models provide insight regarding required plant size and number of plants needed to mesh with the fuel recycling line. They also determine requirements for automation.

Manufacturing models for large-scale production in a hot cell environment are also developed. Combined, these two models allow the assessment …

Design And Evaluation Of Processes For Transmuter Fuel Fabrication, Georg F. Mauer

Fuels Campaign (TRP)

• Project Objective: examine autonomous robotic fuel fabrication processes with regard to hot cell and equipment design, operations, and costs.

• Fabrication processes for different fuel types differ in terms of equipment types, throughput, and cost.

• Design options are restricted by the requirement to employ only radiation-hardened machinery and components

• Benefit to Department of Energy: decision support for the selection of the most suitable manufacturing process.

Investigation Of The Corrosion Of Steel By Lead-Bismuth Eutectic (Lbe) Using Scanning Electron Microscopy And X-Ray Photoelectron Spectroscopy, Daniel Koury

UNLV Theses, Dissertations, Professional Papers, and Capstones

Lead Bismuth Eutectic (LBE) has been proposed for use in programs for accelerator transmutation of waste. LBE is the leading candidate material as a spallation target and an option for the sub-critical blanket coolant. The corrosion of 316 and 316L stainless steels by LBE has been studied using UNLV's facilities for Scanning Electron Microscopy (SEM) and X-ray Photoelectron Spectroscopy (XPS). We have compared exposed and unexposed samples and studied the differences. Some amount of surface contamination is present on the samples and has been removed by ionbeam etching. The unexposed samples reveal typical stainless steel characteristics: a chromium oxide passivation …

Design And Evaluation Of Processes For Fuel Fabrication: Quarterly Progress Report #5, Georg F. Mauer

Fuels Campaign (TRP)

The fifth quarter of the project covered the following:

· Literature Search: The process of evaluating the pertinent literature continued.

· Mr. Richard Silva continued the development of a simulation model with a Waelischmiller hot cell robot. Rich will continue to develop detailed 3-D process simulation models as his M.Sc. thesis project.

· Dr. Mauer presented a paper at the ANS Winter annual meeting in Washington, D.C. titled: “Design and Evaluation of Processes for Transmuter Fuel Fabrication.”

· Concepts and Methods for Vision-Based Hot Cell Supervision and control (Ph.D. Student Jae-Kyu Lee )

· Dr. Mauer presented a paper at …

Development Of A Systems Engineering Model Of The Chemical Separations Process: Quarterly Progress Report 8/16/02- 11/15/02, Yitung Chen, Randy Clarksean, Darrell Pepper

Separations Campaign (TRP)

Two activities are proposed in this Phase I task: the development of a systems engineering model and the refinement of the Argonne code AMUSE (Argonne Model for Universal Solvent Extraction). The detailed systems engineering model is the start of an integrated approach to the analysis of the materials separations associated with the AAA Program. A second portion of the project is to streamline and improve an integral part of the overall systems model, which is the software package AMUSE. AMUSE analyzes the UREX process and other related solvent extraction processes and defines many of the process streams that are integral …

Corrosion Of Steel By Lead Bismuth Eutectic: Quarterly Report August September October 2002, John Farley

Transmutation Sciences Materials (TRP)

We continued with sputter depth profiling of 316 and 316L steel samples that have been exposed to LBE. We also calibrated the sputter depth profiling using a sample of SiO₂ on Si, and the SEM. This is a valuable independent determination of the thickness of oxide layers.

In the laboratory, progress continues using the XPS machine. Experiments have been performed on steel samples using Argon ions to mill away the surface of the sample, thereby making measurements as a function of depth. This "ion beam milling" proceeds slowly through the oxide layer that covers the steel sample. We are …

Developing A Sensing System For The Measurement Of Oxygen Concentration In Liquid Pb-Bi Eutectic: Quarterly Progress Report (Aug. 01 – Oct. 31, 2002), Yingtao Jiang, Bingmei Fu, Woosoon Yim

Transmutation Sciences Materials (TRP)

After two month intensive work in LANL, some preliminary sensor calibration curves have been obtained. Further data analysis shall be performed to assess the theoretical and measured data. Also, a new experimental apparatus shall be designed and located in UNLV to continue the left work.

Technical Progress:

• A set of calibration curves of voltage vs. temperature ranging from 300⁰C to 500⁰C under various oxygen concentrations in liquid LBE for the YSZ oxygen sensor has been obtained and has been reported in one paper.

• A meeting with LBE committee and other faculty members in AAA …

University Of Nevada, Las Vegas Advanced Accelerator Applications University Participation Program: Quarterly Report, First Quarter Year 2 (March 2002 To May 2002), Anthony Hechanova

Transmutation Research Program Reports (TRP)

This Quarterly Report is a primary deliverable from the University of Nevada, Las Vegas (UNLV) Advanced Accelerator Applications (AAA) University Participation Program (UPP) Director to the U.S. Department of Energy (DOE) as described in the UNLV AAA proposal, and Statement of Work for the First Quarter Year 2 and AAA FY02 Work Package.

The UNLV AAA UPP Director implements the program’s administration using staff from the Harry Reid Center for Environmental Studies (HRC) to ensure that work conducted under the UNLV AAA UPP meets program objectives. The UNLV AAA program consists of four components: Program Support, Research Infrastructure Augmentation, International …

University Of Nevada, Las Vegas Advanced Accelerator Applications University Participation Program: Quarterly Report, Third Quarter Year 2 (Sept. 2002 To Nov. 2002), Anthony Hechanova

Transmutation Research Program Reports (TRP)

This Quarterly Report is a primary deliverable from the University of Nevada, Las Vegas (UNLV) Advanced Accelerator Applications (AAA) University Participation Program (UPP) Director to the U.S. Department of Energy (DOE) as described in the UNLV AAA proposal and Statement of Work for the Fourth Quarter.

The UNLV AAA UPP Director implements the program’s administration using staff from the Harry Reid Center for Environmental Studies (HRC) to ensure that work conducted under the UNLV AAA UPP meets program objectives. The UNLV AAA program consists of three components: Program Support, Research Infrastructure Augmentation, and Student Research.

Development Of A Mechanistic Understanding Of High-Temperature Deformation Of Alloy Ep-823 For Transmutation Applications: Annual Progress Report (September 2001 – August 2002), Ajit K. Roy, Brendan O'Toole

Transmutation Sciences Materials (TRP)

The purpose of this project is to evaluate the elevated temperature tensile properties of Alloy EP-823, a leading target material for accelerator-driven waste transmutation applications. This alloy has been proven to be an excellent structural material to contain the lead-bismuth-eutectic (LBE) nuclear coolant needed for fast spectrum operations. Very little data exist in the open literature on the tensile properties of this alloy. The test material will be thermally treated prior to the evaluation of its tensile properties at temperatures relevant to the transmutation applications. The deformation characteristics of tensile specimens, upon completion of testing, will be evaluated by surface …

Development Of A Systems Engineering Model Of The Chemical Separations Process, Yitung Chen, Randy Clarksean, Darrell Pepper

Separations Campaign (TRP)

The AAA program is developing technology for the transmutation of nuclear waste to address many of the long-term disposal issues. An integral part of this program is the proposed chemical separations scheme. This process, as envisioned by Argonne National Laboratory (ANL) researchers, will be outlined later in this report.

Nearly all issues related to risks to future generations arising from long-term disposal of such spent nuclear fuel is attributable to ~1% of its content. This 1% is made up primarily of plutonium, neptunium, americium, and curium (the transuranic elements) and long-lived isotopes of iodine and technetium created as products from …

Modeling, Fabrication, And Optimization Of Niobium Cavities: Phase Ii Quarterly Report, Robert A. Schill Jr., Mohamed Trabia

Transmutation Sciences Materials (TRP)

Multipacting is one of the major loss mechanisms in rf superconductivity cavities for accelerators. This loss mechanism limits the maximum amount of energy/power supported by the cavities. Optimal designs have been identified in others’ studies. In practice, these designs are not easily manufactured. Chemical etching processes used to polish the cavity walls result in a nonuniform surface etch. A nonuniform surface etch will leave some unclean areas with contaminants and micron size particles. These significantly affect mutipacting. Further, a nonuniform etch will leave areas with damaged grain structure, which is not good for superconducting properties. Typically, the depth of chemical …

Hydrogen-Induced Embrittlement Of Candidate Target Materials For Applications In Spallation-Neutron-Target Systems: Quarterly Progress Report (June 01 – August 31, 2002), Ajit K. Roy, Brendan O'Toole

Transmutation Sciences Materials (TRP)

The primary objective of this task is to evaluate the effect of hydrogen on environment-assisted cracking of candidate target materials for applications in spallation-neutron-target (SNT) systems such as accelerator production of tritium (APT) and accelerator transmutation of waste (ATW). The materials selected for evaluation and characterization are martensitic stainless steels including Alloy HT-9, Alloy EP 823 and Type 422 stainless steel. The susceptibility to stress corrosion cracking (SCC) and hydrogen embrittlement (HE) of these materials are being evaluated in environments of interest using tensile specimens under constant load and slow-strain-rate (SSR) conditions. Further, the localized corrosion behavior of these alloys …