1. NAME AND TITLE
TDA: A Time-Dependent, Multigroup, One-Dimensional, Discrete Ordinates Transport Code System.
TDA (Time Dependent ANISN) is a version of the one-dimensional discrete ordinates code, CCC-254/ANISN, with the time-dependent behavior of the particles of interest included in the difference equations. Delayed neutron and other time-dependent effects (such as changes in temperature, composition, etc.) are not accounted for in this version. The time dependence included in the code is due entirely to what might be termed "time streaming" or the velocity of the particles.
Los Alamos Scientific Laboratory, Los Alamos, New Mexico.
Oak Ridge National Laboratory, Oak Ridge, Tennessee.
Sandia National Laboratory, Albuquerque, New Mexico.
The three referenced document numbers (for the same report) indicate the "joint effort"in creating this code. The code was originally written at ORNL for the IBM computers and was subsequently partially rewritten and adapted to the CDC 6600 computer at Sandia Laboratories. The mainframe veresions of TDA were tested extensively at Sandia Laboratories and at Los Alamos National Laboratory (LANL), as well as at the Naval Weapons Evaluation Facility (NWEF) in Albuquerque.
3. CODING LANGUAGE AND COMPUTER
Fortran; CDC, IBM 360/370, Sun, IBM RS/6000 (C00180/MNYWS/01).
4. NATURE OF PROBLEM SOLVED
TDA is a time-dependent discrete ordinates radiation transport computer code. The results of application of the code can be applied to several nonphysical problems having approximate analytical solutions and to the real problem of a neutron-pulsed subcritical 239Pu sphere. In the latter problem, neutron and photon leakage rates are presented as functions of energy and time. The neutronic response time of this pure metal system is 10 to 20 nsec. The TDA code performs well, with the discrete limitation, provided that care is taken to assure proper convergence of the Sn iteration scheme.
5. METHOD OF SOLUTION
The code handles time-dependent coupled neutron-gamma-ray transport problems. It can also evaluate flux and neutron induced gamma-rays with subsequent transport of gamma-rays in air from a nuclear explosion. Here the source can have a neutron as well as a gamma-ray component. One possibility is 42-group (30-neutron, 12-gamma) cross section sets. These cross section sets were generated by H. A. Sandmeier at LANL and are available for most elements. The processing of the dependent data is very involved and time-consuming without automated output processing codes and plotting routines.
6. RESTRICTIONS OR LIMITATIONS
7. TYPICAL RUNNING TIME
The sample problem took 4 1/2 minutes on the IBM 360/75.
8. COMPUTER HARDWARE REQUIREMENTS
TDA was developed on an IBM 360/91 computer and was ported to CDC in the early 1970's. These mainframe versions were last updated in 1981. At Sandia National Laboratory, the IBM 360 version was converted to run on Sun workstations. At ORNL, the IBM 360 version was converted run on IBM RS/6000 workstations. These new workstation releases were added to the RSICC package in the April 2003 update. No changes were made to the mainframe versions, but they are still included in the distribution.
9. COMPUTER SOFTWARE REQUIREMENTS
TDA was developed on an IBM 360/91 operating system with the FORTRAN H compiler. At RSICC, the work station versions were tested on:
Sun UltraSparc under SunOS 5.6 with Sun Workshop Fortran 77 5.0
IBM RS/6000 under AIX 4.3.3 with XL Fortran Ver 7.1
S. A. Dupree, H. A. Sandmeier, G. E. Hansen, W. W. Engle, Jr., F. R. Mynatt, "Time-Dependent Neutron and Photon Transport Calculations using the Method of Discrete Ordinates," LA-4557 (ORNL-4662) (SAI 70-125) (May 1971).
N. M. Greene, J. L. Lucius, J. E. White, R. Q. Wright, C. W. Craven, Jr., and M. L. Tobias, "Appendix ADescription of FIDO Input Format, excerpted from ORNL-TM-3646 (April 1972).
11. CONTENTS OF CODE PACKAGE
The package is transmitted on a CD which contains the referenced documents in a PDF file and an information file, source codes and sample problem input and output written in a Unix tar file.
12. DATE OF ABSTRACT
June 1972; updated May 1975, January 1978, April 2003.
KEYWORDS: NEUTRON; GAMMA-RAY; DISCRETE ORDINATES; MULTIGROUP; TIME-DEPENDENT; SLAB; ONE-DIMENSION