1. NAME AND TITLE

AXMIX-PC: ANISN Cross Section Mixing Code System.

2. CONTRIBUTOR

Technical University of Prague, Prague, Czechoslovakia.

3. CODING LANGUAGE AND COMPUTER

Fortran 77 and Assembler Language; IBM PC, IBM PC/XT, IBM PC/AT, PC 386.

4. NATURE OF PROBLEM SOLVED

AXMIX provides a fast, simple, and economical tool for creating cross-section data sets for ANISN and DOT from cross-section sets already available on cards, nuclide-organized libraries, and group-independent data sets. Numerous options including adjointing, P_n adjustments, changing table length, mixing, transport corrections of ANISN-type cross sections, and management of cross-section data sets and libraries are available.

5. METHOD OF SOLUTION

The number of energy groups which will fit into the core allocated is determined first. If all groups will fit, the solution is straightforward; if not, then the maximum number of groups which will fit is processed repeatedly using direct access I/O routines written in Assembler language.

6. RESTRICTIONS OR LIMITATIONS

AXMIX is limited in its ability to process cross-sections with upscatter and extra caution must be used with them. This is due to the difference in the location of the total upscatter coefficient in ANISN and DOT cross sections. A special section on upscatter is therefore included in the document.

7. TYPICAL RUNNING TIME

On an IBM PC/XT, 4.77 MHz, sample problem 1 took about 8 minutes; sample problem 2 took only a few seconds. The IBM PC/XT had an 8087 math co-processor.

8. COMPUTER HARDWARE REQUIREMENTS

AXMIX-PC runs on the IBM PC, IBM PC/XT, IBM PC/AT and PC 386. At least 256 K bytes of memory are required.

9. COMPUTER SOFTWARE REQUIREMENTS

Fortran 77 and Assembler compilers are required. The code was compiled with Microsoft Fortran Version 5.0 and MASM Version 5.10 under the DOS 3.3 operating system.

10. REFERENCES

Z. Novotny, "README," Informal Notes, Technical University of Prague, Prague, Czechoslovakia (November 13, 1990).

G. D. Haynes, "The AXMIX Program for Cross Section Mixing and Library Arrangement," ORNL/TM-5295 (December 2, 1974).

W. W. Engle, Jr., "AMP (Activity Manipulation Program)," Originally ORNL/TM-5296 (June 16, 1975).

W. A. Rhoades, "The GIP Program for Preparation of Group-Organized Cross Section Libraries," Informal Notes (November 1975).

11. CONTENTS OF CODE PACKAGE

Included are the referenced documents and one DS/DD 5.25-inch diskette (360 K) which contains the source code plus sample problem input and output.

12. DATE OF ABSTRACT

January 1991.