CCC-0543 TORT-DORT.

1. NAME OR DESIGNATION OF PROGRAM:  TORT-DORT.

3. DESCRIPTION OF PROGRAM OR FUNCTION

TORT calculates the flux or fluence of particles due to particles incident upon the system from  extraneous sources or generated internally as a result of interaction with the system. TORT is used in two- or three- dimensional geometric systems, and DORT is used in one- or two- dimensional geometric systems. The principle application is to the deep-penetration transport of neutrons and photons. Certain reactor  eigenvalue problems can also be solved. Numerous printed edits of the results are available, and results can be transferred to output  files for subsequent analysis. Note that the PC release is 2.7.3.

4. METHOD OF SOLUTION

The Boltzmann transport equation is solved using the method of discrete ordinates to treat the directional variable and finite-difference methods to treat spatial variables. Energy dependence is treated using a multigroup formulation. Time dependence is not treated. Starting in one corner of a mesh, at the  highest energy, and with starting guesses for implicit sources, boundary conditions and recursion relationships are used to sweep into the mesh for each discrete direction independently. Integral quantities such as scalar flux are obtained from weighted sums over the directional results. The calculation then proceeds to  lower energy groups, one at a time.
Iterations are used to resolve implicitness caused by scattering between directions within a single energy group, by scattering from  an energy group to another group previously calculated, by fission,  and by certain boundary conditions. Methods are available to accelerate convergence. Anisotropic scattering is represented by a Legendre expansion of arbitrary order, and methods are available to  mitigate the effect of negative scattering estimates resulting from  finite truncation of the expansion. Direction sets can be biased, concentrating work into directions of particular interest.
Fixed sources can be specified at either external or internal mesh boundaries, or distributed within mesh cells.

5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

External forces and  nonlinear physical effects cannot be treated. Penetration through large, non-scattering regions may become inaccurate due to ray effects. Problems with scattering ratios near unity or eigenvalue calculations with closely spaced eigenvalues may be quite time- consuming. Flexible dimensioning is used throughout so that fixed limits on group, problem size, etc., are applicable.

6. TYPICAL RUNNING TIME

Central processor unit (CPU) time used by the flux sweep is roughly proportional to the number of flux calculations:
space = mesh cells * directions * energy groups * iterations/group

NEA-DB implemented the package on an IBM/compatible 33-Mhz PC. The 21 test cases included in the package executed in 6.5 hours.

8. RELATED AND AUXILIARY PROGRAMS

DORT: Two-dimensional discrete ordinates transport.
DOS DRIVER: Coordinates execution of problems.
GIP: Prepares cross-section input files.
RTFLUM:Edits flux files and converts between various flux file formats.
BNDRYS:Selects boundary fluxes for subsequent use as internal boundary sources.
GRTUNCL:Prepares first-collision source due to a point source in R-Z geometry.
ALC: Provides updating and editing of libraries.
TORSED: Constructs TORT boundary soures from external DORT flux files
TORSET:Constructs TORT boundary sources from external TORT lux files
VISA:Processes DORT directional fluxes for selected space cells into format suitable for TORSED.

10. REFERENCES

- Alice F. Rice and Robert W. Roussin (Editors)
  Deterministic Methods in Radiation Transport
  A Compilation of Papers Presented February 4-5, 1992
  ORNL/RSIC-54

- W.A. Rhoades: Improved Mesh Checking Memo (January 11, 1993)
- W.A. Rhoades: TORT Version 2.5 Memo (October 29 1992)
- W.A. Rhoades: TORT and DORT Abstracts
- W.A. Rhoades: README Informal Notes (1991)
- W.A. Rhoades: Documentation Extracted from Sources Files (January 1992)
- W.A. Rhoades: Alert Regarding Value of NTDSI
- W.A. Rhoades: The TORT Three-Dimensional Discrete Ordinates Neutron/Photon
Transport Code ORNL-6268 (November 1987)
- W.A. Rhoades and R.L. Childs: An Updated Version of the DOT 4 One- and
Two-Dimensional Neutron/Photon Transport Code ORNL-5851 (April 1982)
- W.A. Rhoades and M.B. Emmett: DOS - The Discrete Ordinates System
ORNL/TM-8362 (September 1982)
- R.L. Childs: GRTUNCL - First Collision Source Program ORNL Informal Notes
(1982)
- R.L. Childs and W.A. Rhoades: Theoretical Basis of the Linear Nodal and
Linear Characteristic Methods in the TORT Computer Code ORNL-TM-12246 (January
1993)

11. MACHINE REQUIREMENTS

TORT runs on Cray computer, IBM RISC 6000, SUN, DEC Alpha and Hewlett-Packard workstation. The PC release runs  on both 80386 and 80486 personal computers equipped with a math coprocessor and 8 Mbytes of fast memory. All sample problems were also run with only 4 Mbytes of memory with 4 Mbytes set aside for a
ramdisk. Nominal hard disk requirements are around 25 Mbytes with another 25-5- Mbytes needed to run TORT sample problem number 6.

The package was implemented at NEA-DB on a DELL 486P/33MHz PC with 8 Mbytes of RAM.

13. OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED

TORT can operate  in a 100% FORTRAN configuration. On Cray, two optional assembler routines provide added speed. On IBM, two optional C routines provide time, data and location information. The Cray version runs under UNICOS version 5 or 6 using the CFT77 compiler version 4 or 5. Library calls are made to the standard UNICOS library to provide time, date, etc. On IBM, AIX version 3 was used with the XLF version 2 release 3 compiler and no library calls were made. The Sun F77 version 1.4 compiler was used under Sun Solaris 2.3. Codes were  also tested on the DEC Alpha 3000 model 300 running OSF/1 (Rev. 250). Script files are included for installing on HP, in addition to the previously listed computers. The Fortran77 language standard is  followed closely. An exception is the use of the traditional Hollerith data type as described in the CFT77 document. The PC executables were created using the Lahey F77L-EM/32 Fortran compiler, version 5.01, and the Phar Lap Dos Extender and virtual memory manager under DOS.

To implement the program and run the test cases, the PC ran under MS-DOS Version 5.0. The source code was compiled with the  Lahey F77L-EM/32 Fortran-77 Version 5.11 compiler and linked with the 386LINK protected-mode linker version 5.1.

15. NAME AND ESTABLISHMENT OF AUTHORS

Contributed by: Radiation Safety Information Computational Center
                Oak Ridge National Laboratory
                Oak Ridge, Tennessee, U. S. A.

developed by:   Oak Ridge National Laboratory
                Oak Ridge, Tennessee, U. S. A.
                under:
                Defense Nuclear Agency Sponsorship

Makefile file
Fortran Source files
Input files for TORT
Input files for DORT
Executable file
Batch files
Compiler configuration for implementation
Output files
documentation
Differences file