Physical Sciences and Mathematics Commons^™

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 …

Stress Corrosion Cracking Of Type 422 Stainless Steel, Ramprashad Prabhakaran

Transmutation Sciences Materials (TRP)

This paper presents the results of SCC tests of quenched and tempered martensitic Type 422 SS in neutral and acidic aqueous environments at ambient temperature and 90^oC.The susceptibility of smooth and notched tensile specimens to SCC was evaluated by using constant load (CL) and slow strain rate (SSR) test methods. During CL testing, a calibrated proof ring was used to apply a constant load to the test specimen. The magnitude of the applied stress was based on ambient temperature yield strength of the material. On the contrary, the test specimen during SSR testing was continuously strained in tension …

Effects Of Environmental Variables And Stress Concentration On Cracking Of Spallation Target Materials, Ajit K. Roy, Ramprashad Prabhakaran, Mohammad K. Hossain

Transmutation Sciences Materials (TRP)

This paper presents the results of stress corrosion cracking (SCC) studies of two martensitic target materials, namely Alloy EP-823 and Type 422 stainless steel. The susceptibility to SCC was evaluated by using constantload and slow-strain-rate (SSR) test techniques in neutral (pH: 6-7) and acidic (pH: 2-3) aqueous solutions at ambient temperature and 90^oC. A proof ring was used to apply tensile load to the smooth cylindrical specimen for 30 days in constant-load testing. For SSR testing, the specimen was strained in tension until fracture at a strain rate of 3.3 x 10^-6 sec^-1.

Effects Of Environmental Variables And Stress Concentration On Target Materials, Sudheer Sama

Transmutation Sciences Materials (TRP)

This paper presents a brief summary on stress corrosion cracking (SCC) behavior of alloy HT 9. The susceptibility of this alloy to SCC was evaluated by using constant load and slow strain rate test techniques in neutral and acidic solutions at ambient temperature and 90°C. A proof ring was used to apply tensile load to the smooth specimen for 30 days in constant load testing. In slow strain rate testing, the specimen was continuously strained in tension at a rate of 3.3 × 10^-6 sec^-1 until fracture.

Radiation Transport Modeling Using Parallel Computational Techniques, William Culbreth, Denis Beller

Reactor Campaign (TRP)

The second year of this project involved modeling several aspects of the LANCSE beam experiments:

• Modeling targets of varying diameter in air, in a vacuum, and in the presence of humid air;
• Modeling various proton beam profiles;
• Modeling the effects of off-axis proton beam impingement on the target;
• Modeling the asymmetry introduced by the steel table below the target;
• Modeling the effect of varying ratios of Pb to Bi and the effect of impurities; and
• Modeling the system, including other structures within the test room.

With the experience gained through modeling these systems, the UNLV researchers plan, with the assistance …

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. …

Monte Carlo Verification And Modeling Of Lead-Bismuth Spallation Targets, Daniel R. Lowe

Reactor Campaign (TRP)

No abstract provided.

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.

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.

Quantifying Ecosystem Geomorphology Of The Southern Appalachian Mountains, Scott R. Abella

Public Policy and Leadership Faculty Publications

Geomorphology is a dominant factor influencing vegetation distribution in the southern Appalachians, and quantifying landform characteristics is increasingly important for forest ecosystem classification. This study used slope gradient and two previously published geomorphic indices, terrain shape index and landform index that quantify landform shape and protection, to develop a field-based landform quantification system at four study areas in the southern Appalachians. Six major landform types (ridgetops, nose slopes, linear hillslopes, coves, stream ravines, and stream bottoms) exhibited quantitatively different characteristics, and these differences among landforms were not evident when using only categorical landform descriptions (e.g., convex, concave) that have been …

Perspectives On Economic Analyses For High Level Waste Disposal, Helen R. Neill, Robert H. Neill

Public Policy and Leadership Faculty Publications

There are both internal and external pressures on the U.S. Department of Energy (DOE) to reduce costs of disposal and still maintain radiation protection to both present and future generations. The question arises whether both of these goals are attainable.

Task 1: Geodetic Monitoring Of The Yucca Mountain Region Using Continuous Global Positioning System Measurements, Jonathan Price

Publications (YM)

The principal purpose of the cooperative agreement is to develop and continue providing the public and the Yucca Mountain Site Characterization Office (YMSCO) with an independently derived, unbiased body of scientific and engineering data concerning the study of Yucca Mountain as a potential high level waste repository. Under this agreement, the University and Community College System of Nevada (UCCSN) will perform scientific or engineering research, and develop and foster collaborative working relationships between the Government and academic researchers. The following describes the objectives of Task 1 “Geodetic Monitoring of the Yucca Mountain Region Using Continuous Global Positioning System Measurements” under …

Scientific And Engineering Studies Of Systems, Structures, And Components Important To Safety For A Potential Repository At Yucca Mountain, Nevada, Ian Buckle, E. Manos Maragakis

Publications (YM)

TASK 26: Upgrade of Earthquake Simulation Facilities in the Large-Scale Structures Laboratory at University of Nevada Reno

The objective of this Task was to purchase, install and commission the equipment necessary to upgrade two existing shake tables in the Structures Laboratory at UNR, from uniaxial to biaxial motion.

It was recognized that a parallel effort, funded by NSF and HUD, to add a third biaxial table with identical properties to the upgraded existing tables, would be undertaken at the same time.