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2007

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Full-Text Articles in Nuclear Engineering

A Generic Prognostic Framework For Remaining Useful Life Prediction Of Complex Engineering Systems, Alexander V. Usynin Dec 2007

A Generic Prognostic Framework For Remaining Useful Life Prediction Of Complex Engineering Systems, Alexander V. Usynin

Doctoral Dissertations

Prognostics and Health Management (PHM) is a general term that encompasses methods used to evaluate system health, predict the onset of failure, and mitigate the risks associated with the degraded behavior. Multitudes of health monitoring techniques facilitating the detection and classification of the onset of failure have been developed for commercial and military applications. PHM system designers are currently focused on developing prognostic techniques and integrating diagnostic/prognostic approaches at the system level. This dissertation introduces a prognostic framework, which integrates several methodologies that are necessary for the general application of PHM to a variety of systems. A method is ...


Uncertainty Analysis Of Advanced Fuel Cycles To Control Plutonium Inventories, Thomas Christopher Anderson Dec 2007

Uncertainty Analysis Of Advanced Fuel Cycles To Control Plutonium Inventories, Thomas Christopher Anderson

Masters Theses

This paper assesses the uncertainty associated with the utilization and implementation of advanced fuel cycles to control plutonium inventories. The specific fuel cycles investigated are a partially closed cycle utilizing MOX reactors and completely closed one-tier fuel cycles utilizing fast reactors. Multiple methods for assessing these uncertainties were utilized. A scenario approach that varied the time and number of the implementation of the advanced reactors was used. It was found that the implementation of 3 FR/yr with a CR of 0.5 could reduce the amount of Pu by over 36% in reference to building 3 LWR/yr. In ...


Cavitation Of Mercury In A Centrifugal Pump, David Alan Hooper Dec 2007

Cavitation Of Mercury In A Centrifugal Pump, David Alan Hooper

Masters Theses

Cavitation is a significant concern for the reliable operation of a centrifugal pump. Liquid metal flow loops are used in nuclear, chemical, metal forming, and liquid metal dynamo applications. Understanding of the cavitation characteristics of liquid metals is increasingly important to the design and operation of these facilities. One recent field of cavitation research has developed for mercury flow in spallation targets used in neutron sources. To further the understanding of mercury cavitation, a review of the existing literature on water cavitation, liquid metal cavitation, and mercury cavitation is performed. The mechanics of cavitation and the analytical methods applied to ...


Investigations On Hydrocyclones For The Spallation Neutron Source, Lee Henry Hosack Dec 2007

Investigations On Hydrocyclones For The Spallation Neutron Source, Lee Henry Hosack

Masters Theses

The hydrocyclone is commonly used to separate oil from water, and particulates from fluid streams in various process industries. Two-fluid hydrodynamic theory is used here to develop a model for hydrocyclone performance in the application of separation of helium bubbles larger than 30 micron in diameter from liquid mercury at system pressure near 1 bar. The application is related to high power liquid metal target development for proton beams used in spallation neutron sources.


Artificial Neural Network For Spectrum Unfolding Bonner Sphere Data, Jia Hou Dec 2007

Artificial Neural Network For Spectrum Unfolding Bonner Sphere Data, Jia Hou

Masters Theses

The use of Bonner Sphere Spectrometer (BSS) is a well-established method of measuring the energy distribution of neutron emission sources. The purpose of this research is to apply the Generalized Regression Neural Network (GRNN), a kind of Artificial Neural Network (ANN), to predict the neutron spectrum using the count rate data from a BSS. The BSS system was simulated with the MCNP5 Monte-Carlo code to calculate the response to neutrons of different energies for each combination of thermal neutron detector and polyethylene sphere. One hundred and sixty-three different types of neutron spectra were then investigated. GRNN Training and testing was ...


Nevada Risk Assessment/Management Program – Phase 2 (Nramp2): Quarterly Progress Report July 1, 2007 Through September 30, 2007, Klaus J. Stetzenbach Nov 2007

Nevada Risk Assessment/Management Program – Phase 2 (Nramp2): Quarterly Progress Report July 1, 2007 Through September 30, 2007, Klaus J. Stetzenbach

Nevada Risk Assessment/Management Program

Work conducted in this 4th quarter consisted of 3 major activities:

• Continue the receipt and reconciliation of Area 5 Radioactive Waste Management Site (RWMS) inventory data.

• Receive, review, install, calibrate, and run the Goldsim Area 5 Performance Assessment (PA) Model, and review the supporting parameters and assumptions in the 93-document reference set as a tool for regulatory compliance and closure assessment.

• Identify, review, and compare the interpretation of pertinent regulatory guidelines and orders by DOE sites in compliance for PA, Compliance Assessment (CA), and closure activities - as they may relate to the Nevada Test Site (NTS) Area 5 PA and ...


High Temperature Heat Exchanger Project: Quarterly Progress Report July 1, 2007 Through September 30, 2007, Anthony Hechanova Oct 2007

High Temperature Heat Exchanger Project: Quarterly Progress Report July 1, 2007 Through September 30, 2007, Anthony Hechanova

Publications (NSTD)

• Ceramatec Sulfuric Acid Decomposer. The numerical model of a SiC ceramic coupon with two layers of microchannels was developed. Calculations of the factor of safety and probability of failure for the case of a straight channel were performed. Results for a pressure of 7.5 MPa were performed. The thermal and mechanical stress analyses of the Ceramatec HTHX and decomposer were completed.

• Bayonet Heat Exchanger. The thermal and mechanical stress analyses of the bayonet type HTHX and decomposer (Sandia design) were completed. Temperature profiles obtained from thermocouples measured from the Sandia experiments have been applied to the whole packed bed ...


Time Dependent Discrete Ordinates Neutron Transport Using Distribution Iteration In Xyz Geometry, James R. Dishaw Oct 2007

Time Dependent Discrete Ordinates Neutron Transport Using Distribution Iteration In Xyz Geometry, James R. Dishaw

Theses and Dissertations

The DI algorithm is an alternative to source iteration that, in our testing, does not require an accelerator. I developed a formal verification plan and executed it to verify the results produced by my code that implemented DI with the above features. A new, matrix albedo, boundary condition treatment was developed and implemented so that infinite-medium benchmarks could be included in the verification test suite. The DI algorithm was modified for parallel efficiency and the prior instability of the refinement sweep was corrected. The testing revealed that DI performed as well or faster than source iteration with DSA and that ...


Monaco/Mavric Evaluation For Facility Shielding And Dose Rate Analysis: To Support The Global Nuclear Energy Partnership, Charlotta Sanders, Denis Beller Oct 2007

Monaco/Mavric Evaluation For Facility Shielding And Dose Rate Analysis: To Support The Global Nuclear Energy Partnership, Charlotta Sanders, Denis Beller

Reactor Campaign (TRP)

Monte Carlo methods are used to compute fluxes or dose rates over large areas using mesh tallies. For problems that demand that the uncertainty in each mesh cell be less than some set maximum, computation time is controlled by the cell with the largest uncertainty. This issue becomes quite troublesome in deep-penetration problems, and advanced variance reduction techniques are required to obtain reasonable uncertainties over large areas.

In this project the MAVRIC sequence will be evaluated along with the Monte Carlo engine Monaco to investigate its effectiveness and usefulness in facility shielding and dose rate analyses. A previously MCNP-evaluated cask ...


Implementation Of Uncertainty Propagation In Triton/Keno: To Support The Global Nuclear Energy Partnership, Charlotta Sanders, Denis Beller Oct 2007

Implementation Of Uncertainty Propagation In Triton/Keno: To Support The Global Nuclear Energy Partnership, Charlotta Sanders, Denis Beller

Reactor Campaign (TRP)

Monte Carlo methods are beginning to be used for three-dimensional fuel depletion analyses to compute various quantities of interest, including isotopic compositions of used fuel.1 The TRITON control module, available in the SCALE 5.1 code system, can perform three dimensional (3-D) depletion calculations using either the KENO V.a or KENO-VI Monte Carlo transport codes, as well as the two-dimensional (2- D) NEWT discrete ordinates code. For typical reactor systems, the neutron flux is not spatially uniform. For Monte Carlo simulations, this results in non-uniform statistical uncertainties in the computed reaction rates. For spatial regions where the flux ...


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

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.


Unlv Research Foundation High Temperature Heat Exchanger Development: 9/08, Anthony Hechanova Sep 2007

Unlv Research Foundation High Temperature Heat Exchanger Development: 9/08, Anthony Hechanova

Publications (NSTD)

Barriers addressed:

Nuclear Hydrogen Initiative R&D Plan – Material performance and component design and testing for the intermediate heat exchanger and high-temperature thermochemical water splitting (H2SO4 decomposition and HI decomposition). Improved materials for High Temperature Electrolysis.


Nevada Risk Assessment/Management Program (Nramp) – Phase 2: Quarterly Progress Report April 1, 2007 Through June 30, 2007, Klaus J. Stetzenbach Jul 2007

Nevada Risk Assessment/Management Program (Nramp) – Phase 2: Quarterly Progress Report April 1, 2007 Through June 30, 2007, Klaus J. Stetzenbach

Nevada Risk Assessment/Management Program

Work conducted this quarter consisted of continuing the detailed data and information acquisition; review of the received document contents, and interpretation of significance in light of previous DOE documents. Much of the effort was devoted to reconciling inconsistencies and contradictions in both the primary data bases and in and among the DOE published documents. These review and reconciliation efforts included regular telephone and e-mail correspondence, as well as in-person discussions with DOE NVO personnel at the April DOE Generator Conference in Las Vegas. Reconciliation efforts continued with frequent (daily) exchanges on the inventory data sets, and the engineering descriptions of ...


High Temperature Heat Exchanger Project: Quarterly Progress Report April 1, 2007 Through June 30, 2007, Anthony Hechanova Jul 2007

High Temperature Heat Exchanger Project: Quarterly Progress Report April 1, 2007 Through June 30, 2007, Anthony Hechanova

Publications (NSTD)

• Ceramatec Sulfuric Acid Decomposer. Modeling with different reacting flow channel configurations (ribbed-surface channels, hexagonal channels, and diamond-shaped channels) was performed. The probability of failure for the one channel geometry with different reacting flow channel configurations was calculated to be zero in the three principal directions for all of the cases.

• Bayonet Heat Exchanger. The Matlab code for calculating the probability of failure using a two-dimensional axisymmetric model of the bayonet decomposer was developed. The probability of failure was calculated for the inner and outer SiC walls, and the intermediate quartz wall of the decomposer and found to be zero for ...


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

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.


An Integrated Fuzzy Inference Based Monitoring, Diagnostic, And Prognostic System, Dustin R. Garvey May 2007

An Integrated Fuzzy Inference Based Monitoring, Diagnostic, And Prognostic System, Dustin R. Garvey

Doctoral Dissertations

To date the majority of the research related to the development and application of monitoring, diagnostic, and prognostic systems has been exclusive in the sense that only one of the three areas is the focus of the work. While previous research progresses each of the respective fields, the end result is a variable "grab bag" of techniques that address each problem independently. Also, the new field of prognostics is lacking in the sense that few methods have been proposed that produce estimates of the remaining useful life (RUL) of a device or can be realistically applied to real-world systems. This ...


Nevada Risk Assessment/Management Program (Nramp) – Phase 2: Quarterly Progress Report January 1, 2007 Through March 31, 2007, Klaus J. Stetzenbach Apr 2007

Nevada Risk Assessment/Management Program (Nramp) – Phase 2: Quarterly Progress Report January 1, 2007 Through March 31, 2007, Klaus J. Stetzenbach

Nevada Risk Assessment/Management Program

Work conducted in this second quarter consisted of continuing the detailed data and information acquisition; review of the received document contents, and interpretation of significance in light of previous DOE documents. This included telephone and in-person discussions with DOE NVO personnel at the March Waste Management Symposia in Tucson. As a result of these discussions and review of the supporting data and methodologies, a more specific listing of activities was developed, and DOE provided a confirmatory note to HRC in March.

Much of the review of the received information does indicate significant changes in data, methodologies, and baseline assumptions over ...


High Temperature Heat Exchanger Project: Quarterly Progress Report January 1, 2007 Through March 31, 2007, Anthony Hechanova Apr 2007

High Temperature Heat Exchanger Project: Quarterly Progress Report January 1, 2007 Through March 31, 2007, Anthony Hechanova

Publications (NSTD)

• The variation of sulfur dioxide production (throughput) of the baseline design of the Ceramatec sulfuric acid decomposer with total mass flow rate of reacting flow has been calculated. According to the calculations, the sulfur dioxide production increases as the total mass flow rate of reacting flow increases regardless of the fact that decomposition percentage of sulfuric trioxide decreases. A parametric study of the baseline design of the Ceramatec sulfuric acid decomposer was performed.

• The thermal performance using various channel geometries for the decomposer was studied. The baseline design (straight channels) has 89.5% thermal efficiency while the thermal efficiency of ...


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

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.


A Multireference Density Functional Approach To The Calculation Of The Excited States Of Uranium Ions, Eric V. Beck Mar 2007

A Multireference Density Functional Approach To The Calculation Of The Excited States Of Uranium Ions, Eric V. Beck

Theses and Dissertations

An accurate and efficient hybrid Density Functional Theory (DFT)/Multireference Configuration Interaction (MRCI) model for computing electronic excitation energies in heavy element atoms and molecules was developed. This model incorporated relativistic effects essential for accurate qualitative and quantitative spectroscopic predictions on heavy elements, while simultaneously removing spin-multiplicity limitations inherent in the original model on which it is based. This model was used to successfully compute ground and low-lying electronic states for atoms in the first two rows of the period table, which were used for calibration. Once calibrated, calculations on carbon monoxide, bromine fluoride, the bromine atom, uranium +4 and ...


Precise Calculation Of Complex Radioactive Decay Chains, Logan J. Harr Mar 2007

Precise Calculation Of Complex Radioactive Decay Chains, Logan J. Harr

Theses and Dissertations

This thesis documents a new approach to investigate the gamma radiation activity of the fission products of three different fuels (U-235, U-238, and U-239) exposed to three different incident neutron energy spectra (thermal, fast spectrum, and high energies). An application of the exponential moments function is used with a transmutation matrix in the calculation of complex radioactive decay chains to achieve greater precision than can be attained through current methods. The result of this research is a code which can calculate the decay products from complex radioactive decay chains with a high degree of precision while quantifying the uncertainty in ...


High Resolution Mesoscale Weather Data Improvement To Spatial Effects For Doserate Contour Plot Predictions, Christopher P. Jones Mar 2007

High Resolution Mesoscale Weather Data Improvement To Spatial Effects For Doserate Contour Plot Predictions, Christopher P. Jones

Theses and Dissertations

Reanalysis weather data is obtained for dates surrounding historical nuclear tests and processed through Regional Atmospheric Modeling System (RAMS) software to produce a high-resolution weather forecast. Output from RAMS is visualized to check for validity and input into Hazard Prediction and Assessment Capability (HPAC) software and modeled predictions are compared to historical observation data. Simulations are conducted using constant high resolution weather and varying terrain resolution. The HPAC prediction is numerically compared to historical observation data. The result of this research culminated in the knowledge that early-time, low-altitude wind data was neglected by HPAC's incorporation of the Defense Land ...


Condition Reporting And Resolution, J. M. Pesek, S. A. Wade Mar 2007

Condition Reporting And Resolution, J. M. Pesek, S. A. Wade

Publications (YM)

This procedure facilitates a safety conscious work environment by providing a mechanism for employees to make management aware of existing and potential conditions. This procedure establishes the responsibilities and process to be used to ensure that conditions related to, but not limited to, the environment, safety, health, waste isolation, operations, security, or quality of items and services associated with Office of Civilian Radioactive Waste Management (OCRWM) work activities are promptly identified, controlled, evaluated, and corrected as soon as practical. This procedure describes the process flow, controls, interfaces, and requirements for condition identification and resolution. This includes adverse conditions as well ...


A New Stochastic Model For Systems Under General Repairs, Huairui R. Guo, Haitao Liao, Wenbiao Zhao Mar 2007

A New Stochastic Model For Systems Under General Repairs, Huairui R. Guo, Haitao Liao, Wenbiao Zhao

Haitao Liao

Numerous stochastic models for repairable systems have been developed by assuming different time trends, and re- pair effects. In this paper, a new general repair model based on the repair history is presented. Unlike the existing models, the closed- form solutions of the reliability metrics can be derived analytically by solving a set of differential equations. Consequently, the con- fidence bounds of these metrics can be easily estimated. The pro- posed model, as well as the estimation approach, overcomes the drawbacks of the existing models. The practical use of the proposed model is demonstrated by a much-discussed set of data ...


A New Stochastic Model For Systems Under General Repairs, Haitao Liao Mar 2007

A New Stochastic Model For Systems Under General Repairs, Haitao Liao

Faculty Publications and Other Works -- Industrial & Information Engineering

Numerous stochastic models for repairable systems have been developed by assuming different time trends, and re- pair effects. In this paper, a new general repair model based on the repair history is presented. Unlike the existing models, the closed- form solutions of the reliability metrics can be derived analytically by solving a set of differential equations. Consequently, the con- fidence bounds of these metrics can be easily estimated. The pro- posed model, as well as the estimation approach, overcomes the drawbacks of the existing models. The practical use of the proposed model is demonstrated by a much-discussed set of data ...


Nevada Risk Assessment/Management Program (Nramp) – Phase 2: Quarterly Progress Report, Oct. 1, 2006- Dec. 31, 2006, Klaus J. Stetzenbach Jan 2007

Nevada Risk Assessment/Management Program (Nramp) – Phase 2: Quarterly Progress Report, Oct. 1, 2006- Dec. 31, 2006, Klaus J. Stetzenbach

Nevada Risk Assessment/Management Program

Work conducted in this initial period consisted of work start-up (technical, administrative, contractual), and interviewing/site visits with DOE NVO staff (and support contractors) and HRC staff to quickly ascertain current technical activities and priorities as related to the scope of this task.

Since much of the technical work scope builds on previous technical work, it was considered critical to determine the changes (programmatic, technical, and regulatory) that have occurred over the past several years that directly relate to the scope. It was also equally important to determine the technical and programmatic priorities that have been established in the interim.


High Temperature Heat Exchanger Project: Quarterly Progress Report October 1, 2006 Through December 31, 2006, Anthony Hechanova Jan 2007

High Temperature Heat Exchanger Project: Quarterly Progress Report October 1, 2006 Through December 31, 2006, Anthony Hechanova

Publications (NSTD)

Modifications to the single-channel models of the Ceramatec heat exchanger and decomposer concept for hexagonal flow channels under two values of layer-overlapping (50% and 100%) and for diamond-shaped flow channels were completed.

The finite element calculations of the “Ball on Three Ball Test” for ceramic material for the purpose of selecting the appropriate specimen thickness for future experimental testing was performed for plate thicknesses ranging from 2 to 8 mm.

A finite element model of the “Ball on Three Ball Test” was also studied for discs having micro-channels.


Environmental Effects On Corrosion Properties Of Alloy 22, Mano Misra, L. G. Mcmillion Jan 2007

Environmental Effects On Corrosion Properties Of Alloy 22, Mano Misra, L. G. Mcmillion

Publications (YM)

Subtask 1: Experimental Determination of Parameters for the General Corrosion Model Subtask 2: Corrosion Under Dust Deposits Containing Hygroscopic Salts Subtask 3: Heated Electrode Approach for the Study of Corrosion Under Aggressive Conditions Subtask 4: Effect of Hydrogen Permeation on the Stability of the Passive Film of Alloy 22


Phase Stability And Segregation In Alloy 22 Base Metal And Weldments, Jeffrey Lacombe, G. L. Mcmillon Jan 2007

Phase Stability And Segregation In Alloy 22 Base Metal And Weldments, Jeffrey Lacombe, G. L. Mcmillon

Publications (YM)

Subtask 1: Microstructural Characterization of Phase Stability and Variability in Alloy 22. Develop an improved understanding of Alloy 22 and the extent to which compositional and microstructural variations are present in otherwise “nominal” as-procured material.

Subtask 2: Electrochemical Methods to Detect Susceptibility of Alloy 22 to Localized Corrosion. Study the influence that compositional and microstructural variations have on the corrosion performance of Alloy 22.


Geometrical Modeling Of Fibrous Materials Under Compression, Benoit Maze, Hooman Vahedi Tafreshi, Behnam Pourdeyhimi Jan 2007

Geometrical Modeling Of Fibrous Materials Under Compression, Benoit Maze, Hooman Vahedi Tafreshi, Behnam Pourdeyhimi

Mechanical and Nuclear Engineering Publications

Many fibrous materials such as nonwovens are consolidated via compaction rolls in a so-called calendering process. Hot rolls compress the fiber assembly and cause fiber-to-fiber bonding resulting in a strong yet porous structure. In this paper, we describe an algorithm for generating three dimensional virtual fiberwebs and simulating the geometrical changes that happen to the structure during the calendering process. Fibers are assumed to be continuous filaments with square cross sections lying randomly in the x or y direction. The fibers are assumed to be flexible to allow bending over one another during the compression process. Lateral displacement is not ...