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in subjects: "Mathematical models."

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Examination of the SCEPTRE and CSMP Programs for Solving the Point-Kinetics Equations with Feedback

Two modeling programs, SCEPTRE and CSMP, are used to solve the point-kinetics equations - - seven coupled nonlinear differential equations - - with a linear-feedback function. The constants used are appropriate for EBR-II; therefore the computational accuracy may be tested against the experimental rod drops. Run-time, versatility, programming ease, and accuracy are criteria used to evaluate the two programs. SCEPTRE is found to be more efficient in run time and CSMP more versatile. The ease of … more

Date: September 1976

Creator: Walkowski, P. D. & Peterson, B. R. (Bruce R.)

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Study on Flow Instabilities in Two-Phase Mixtures

Various mechanisms that can induce flow instabilities in two-phase flow systems are reviewed and their relative importance discussed. In view of their practical importance, the density-wave instabilities have been analyzed in detail based on the one-dimensional two-phase flow formulation. The dynamic response of the system to the inlet flow perturbations has been derived from the model; thus the characteristic equation that predicts the onset of instabilities has been obtained. The effects of v… more

Date: March 1976

Creator: Ishii, M.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

One-Dimensional Cladding-Relocation Model for Fast-Reactor Loss-of-Flow Accidents

The motion and location of the molten-cladding during an unprotected loss-of-flow accident in liquid metal fast breeder reactors are important because of the effects on the reactivity and the subsequent fuel motion. The present study analyzes the cladding-relocation problem based on a single-channel film-flow model and a simple thermal transient model for fuel pins. The motion of molten cladding induced by sodium-vapor streaming undergoes initial rapid upward acceleration, slowing down, flow re… more

Date: March 1976

Creator: Ishii, M.; Chen, W. L. & Grolmes, M. A.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Simple Conduction Model with Phase Change for Fuel Pin

A simple conduction model with phase change has been developed for the transient analysis of a fuel pin based on average properties and lumped-parameter techniques. The transient behavior of fuel and cladding can be accurately described by simple analytical expressions that agree with conventional numerical approaches for under-cooling transient analysis. If it be assumed that the heat-transfer resistance between the fuel and cladding remains the same for both steady-state and transient periods… more

Date: April 1976

Creator: Chen, W. L.; Ishii, M. & Grolmes, M. A.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Application of Frequency-Modified Life Approach to the Low-Cycle Fatigue Behavior of Type 304 Stainless Steel

The application of the frequency-modified life equation to fatigue life prediction has been critically examined using the extensive fatigue data generated for Type 304 stainless steel at 1100 degrees F under a variety of cyclic-loading conditions. The parameters that enter into the frequency-modified life equation vary with strain rate and show a transition coinciding with the frequency of cycling at which a change in the fracture appearance from predominantly transgranular to predominantly int… more

Date: May 1976

Creator: Maiya, P. S. & Majumdar, S.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Experimental and Analytical Study of the Sputtering Phenomena

An experimental apparatus was constructed to examine the heat-transfer characteristics of a sputtering front. In the present study, a heat source of sufficient intensity was located immediately below the sputtering front, which prevented its downward progress, thus permitting detailed measurements of steady-state surface temperatures throughout a sputtering front. A two-dimensional analytical model was developed to describe a stationary sputtering front where the wet-dry interface corresponds t… more

Date: March 1976

Creator: Howard, Paul A.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Analysis of a Cylindrical Shell Vibrating in a Cylindrical Fluid Region

Analytical and experimental methods are presented for evaluating the vibration characteristics of cylindrical shells such as the thermal liner of the Fast Flux Test Facility (FFTF) reactor vessel. The NASTRAN computer program is used to calculate the natural frequencies, mode shapes, and response to a harmonic loading of a thin, circular cylindrical shell situated inside a fluid-filled rigid circular cylinder. Solutions in a vacuum are verified with an exact solution method and the SAP IV compu… more

Date: August 1976

Creator: Chung, Ho; Mulcahy, T. M.; Turula, P. & Jendrzejczyk, J. A.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Studies of Unprotected Loss-of-Flow Accidents for the Clinch River Breeder Reactor

Studies of unprotected loss-of-flow accidents in the CRBR for various rates of flow coast-down and with various options in the SAS 3A code did not lead to conditions for a violent disassembly. Maximum fuel temperatures using the SLUMPY module for disassembly were in the range 4000-4500 deg C. An approximate treatment of the LOF-driven TOP accident, not properly modeled by SAS 3A, indicates the possibility of some increase in accident severity. The effect of fission gas in dispersing fuel was no… more

Date: April 1976

Creator: Hummel, Harry H.; Pizzica, P. A. & Kalimullah

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Reactivity and Power Shape Control : Theory and Numerical Applications

An optimization method, based on linear programming, has been developed which determines the enrichment distribution in a multizone reactor such that the desired power distribution is achieved at BOL, as well as the poison distribution during reactor operation such that the reactor is kept critical and the desired power distribution is retained. For the numerical implementation of the method, the CYPRUS code has been written. Results of the application of the method are presented and input spec… more

Date: June 1976

Creator: Tzanos, Constantine P.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Accuracy of the Finite Analytic Method for Scalar Transport Calculations

The accuracy of the finite analytic method of discretizing fluid flow equations is assessed through calculations of multidimensional scalar transport. The transport of a scalar function in a uniform velocity flow field inclined with the finite-difference grid lines is calculated for a range of grid Peclet numbers and flow skewness. The finite analytic method is observed to be superior to the approach of constructing finite-difference analogs from locally one-dimensional resolution of the flow v… more

Date: September 1984

Creator: Vanka, S. P.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Leakage Flow-Induced Vibrations for Variations of a Tube-in-Tube Slip Joint

Variations in the design of a specific slip joint separating two cantilevered, telescoping tubes conveying water were studied to determine their effect upon the leakage flow-induced vibration self-excitation mechanism known to exist for the original slip joint geometry. The important parameters controlling the self-excitation mechanism were identified, which, along with previous results, allowed the determination of a comprehensive set of design rules to avoid unstable vibrations. This was poss… more

Date: January 1986

Creator: Mulcahy, T. M.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Flow-Induced Vibration of Circular Cylindrical Structures

This report summarizes the flow-induced vibration of circular cylinders in quiescent fluid, axial flow, and crossflow, and applications of the analytical methods and experimental data in design evaluation of various system components consisting of circular cylinders.

Date: June 1985

Creator: Chen, Shoei-Sheng

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Three-Dimensional Thermal Modeling of Electric Vehicle Batteries

A generic three-dimensional thermal model was developed for analyzing the thermal behavior of electric-vehicle batteries. The model calculates temperature distribution and excursion of a battery during discharge, change, and open circuit. The model takes into account the effects of heat generation, internal conduction and convection, and external heat dissipation on the temperature distribution in a battery. The three-dimensional feature of the model permits incorporation of various asymmetric … more

Date: October 1985

Creator: Lee, Johnsee; Choi, K. W.; Yao, N. P. & Christianson, C. C.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

On the Experimental Operation of a Sodium Heat Pipe

This report documents the operation of a 28 in. long sodium heat pipe in the Heat Pipe Test Facility (HPTF) installed at Argonne National Laboratory. Experimental data were collected to simulate conditions prototypic of both a fluidized bed coal combustor application and a space environment application. Both sets of experiment data show good agreement with the heat pipe analytical model. The heat transfer performance of the heat pipe proved reliable over a substantial period of operation and ov… more

Date: May 1985

Creator: Holtz, Robert E.; McLennan, G. A. & Koehl, E. R.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Mathematical Modeling and Evaluation of Radionuclide Transport Parameters from the ANL Laboratory Analog Program

Computer model simulation is required to evaluate the performance of proposed or future high-level radioactive waste geological repositories. However, the accuracy of a model in predicting the real situation depends on how well the values of the transport properties are prescribed as input parameters. Knowledge of transport parameters is therefore essential. We have modeled ANL's Experiment Analog Program which was designed to simulate long-term radwaste migration process by groundwater flowing… more

Date: July 1984

Creator: Chen, B. C-J.; Hull, J. R.; Seitz, M. G.; Sha, William T.; Shah, V. L. & Soo, S. L.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Thermodynamic Analysis of Multicomponent Working Fluids for Rankine Bottoming Cycle Applications

The basic equations underlying a computer code are developed to describe the thermodynamic behavior of multi-component working fluids in Rankine cycles. The code is to be employed in the performance analysis of Rankine bottoming cycle systems. The performance of such systems depends strongly on the working fluid characteristics. The introduction of multi-component mixtures makes available a broad spectrum of fluid properties achievable by varying the mixture composition. The code provides a too… more

Date: January 1984

Creator: Ash, J. E.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Proceedings of the Workshop on Electronic and Ionic Collision Cross Sections Needed in the Modeling of Radiation Interactions with Matter, Held at Argonne National Laboratory December 6-8, 1983

The term modeling in the Workship title refers to the mathematical analysis of the consequences of many collision processes for characterizing the physical stage of radiation actions. It requires as input some knowledge of collision cross sections. Traditionally, work on cross sections and work on the modeling are conducted by separate groups of scientists. It was the purpose of the Workshop to bring these two groups together in a forum that would promote effective communication. Cross-section … more

Date: May 1984

Creator: Argonne National Laboratory

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Statistical Identification of Effective Input Variables

This report provides background and procedural information for the use of a general-purpose Stirling-engine analysis code developed at Argonne National Laboratory and available through the National Energy Software Center. Different engine configurations are easily specified, or the user may make use of provided data for existing engines, both kinematic and free piston. The code models heat transfer and fluid mechanics throughout the engine and accounts for system energy flows and losses. Good a… more

Date: September 1982

Creator: Vaurio, J. K.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

DIF3D: A Code to Solve One-, Two-, and Three-Dimensional Finite-Difference Diffusion Theory Problems

The mathematical development and numerical solution of the finite-difference equations are summarized. The report provides a guide for user application and details the programming structure of DIF3D. Guidelines are included for implementing the DIF3D export package on several large scale computers. Optimized iteration methods for the solution of large-scale fast-reactor finite-difference diffusion theory calculations are presented, along with their theoretical basis. The computational and data … more

Date: April 1984

Creator: Derstine, K. L.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Stability of Tube Rows in Crossflow

A mathematical model for the instability of tube rows subjected to crossflow is examined. The theoretical model, based on the fluid-force data for a pitch-to-diameter ratio of 1.33, provides additional insight into the instability phenomenon. Tests are also conducted for three sets of tube rows. The effects of mass ratio, tube pitch, damping, detuning and finned tubes are investigated. Theoretical results and experimental data are in good agreement.

Date: October 1982

Creator: Chen, S. S. & Jendrzejczyk, J. A.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Elastic-Plastic Constitutive Modeling of Concrete

The need to understand concrete behavior under high temperatures in the nuclear industry has become rather acute. For this purpose, a constitutive model of concrete especially developed for this severe environment is indispensable. This report reviews the presently available constitutive models of concrete at standard-temperature conditions and considers their advantages and drawbacks. A rather simple but effective approach is selected to treat concrete behavior at high temperatures. Special em… more

Date: March 1983

Creator: Takahashi, Yukio

Item Type: Report

Partner: UNT Libraries Government Documents Department

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The Optical Properties and Complex Dielectric Function of Metallic Aluminum from 0. 04 to 10⁴ eV

Measurements of the optical properties of metallic aluminum are reviewed and available data are analyzed to obtain the bulk values of the optical constants and the complex dielectric function from 0.04 eV to 10 keV. The intra- and interband contributions to the dielectric function are discussed briefly, and recently proposed values for the Drude parameters describing the intraband absorption are critically considered. Factors influencing experimental measurements are discussed with emphasis on … more

Date: March 1983

Creator: Smith, D. Y.; Shiles, E. & Inokuti, Mitio

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Natural Thermal Stratification in Tanks : Phase 1 Final Report

This report describes how solar system tanks fail to stratify, a new solar system control strategy that allows stratification, a one-dimensional analytical model of thermally stratified tanks, experimental measurement of thermal stratification in tanks, correlation of experimental measurements with empirical constants in the analytical model, and a procedure for designing thermally stratified tanks. Failure to stratify is explained in terms of the critical Richardson number. The key to the new … more

Date: February 1982

Creator: Cole, Roger Lynn & Bellinger, F. O.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Effects of Curvature on Asymmetric Steady States in Catalyst Particles

The effects of curvature on steady states of chemical catalytic reactions are investigated by studying the cases of the catalytic particle being a spherical or cylindrical shell. Existence and stability of solutions are studied. It is shown that the solutions converge to the solutions for the catalytic slab when the curvature goes to 0 in each case.

Date: February 1981

Creator: Lucier, Bradley J.

Item Type: Report

Partner: UNT Libraries Government Documents Department