1. NAME AND TITLE

ASOP: Multigroup One-Dimensional Discrete Ordinates Transport Code System for Shield Optimization.

AUXILIARY ROUTINE

ANISN: The CCC-254A/ANISN-ORNL source file is included in this package.

2. CONTRIBUTOR

Oak Ridge National Laboratory, Oak Ridge, Tennessee.

3. CODING LANGUAGE AND COMPUTER

FORTRAN 77; IBM RS/6000 and IBM PC running Linux. (C00126IRISC00).

4. NATURE OF PROBLEM SOLVED

ASOP is a shield optimization calculational system based on the one-dimensional discrete ordinates transport code system ANISN (CCC-254). It has been used to design optimum shields for space applications of SNAP zirconium-hydride-uranium-fueled reactors and uranium-oxide fueled thermionic reactors and to design beam stops for the ORELA facility.

5. METHOD OF SOLUTION

ASOP generates coefficients of linear equations describing the logarithm of the dose and dose-weight derivatives as functions of position from data obtained in an automated sequence of ANISN calculations. With the dose constrained to a design value and all dose-weight derivatives required to be equal, the linear equations may be solved for a new set of shield dimensions. Since changes in the shield dimensions may cause the linear functions to change, the entire procedure is repeated until convergence is obtained.

The detailed calculations of the radiation transport through shield configurations for every step in the procedure distinguish ASOP from other shield optimization computer code systems which rely on multiple component sources and attenuation coefficients to describe the transport.

6. RESTRICTIONS OR LIMITATIONS

Problem size is limited only by machine size.

7. TYPICAL RUNNING TIME

The sample case executed in about 1 minute on IBM RS/6000 model 590.

8. COMPUTER HARDWARE REQUIREMENTS

The code runs on the IBM RS/6000 or on IBM compatible personal computers running Linux.

9. COMPUTER SOFTWARE REQUIREMENTS

RSICC tested ASOP on the IBM RS/6000 with xlf 3.2.5.4 compiler under AIX and on a Pentium running RedHat Linux with g77 (egcs-1.0.3).

10. REFERENCES

a. Included in documentation:

ASOP README (August 20, 1998).

Ward W. Engle, Jr., "A Users Manual for ASOP, ANISN Shield Optimization Program," CTC-INF-941 (September 1969).

b. Background information included in CCC-254/ANISN-ORNL document:

W. W. Engle, Jr., "ANISN, A One-Dimensional Discrete Ordinates Transport Code with Anisotropic Scattering," K-1693 (March 1967).

W. W. Engle, M. A. Boling, and B. W. Colston, "DTF-II, A One-Dimensional, Multigroup Neutron Transport Program," NAA-SR-10951 (March 1966).

11. CONTENTS OF CODE PACKAGE

Included are the referenced document and one DS/HD (1.44MB) Unix-formatted diskette which contains a GNU compressed tar file with the source codes, sample problem input and output, and makefiles for both AIX and Linux.

12. DATE OF ABSTRACT

August 1971; December 1984; July 1988, August 1998.