**1. NAME AND TITLE**

AUS98: The 1998 Version of the AUS Modular Neutronics Code System.

**AUXILIARY PROGRMS**

BCDBINXS: Changer of cross section library from ASCII to binary.

BCDBINFP: Changer of fission product decay library from ASCII to binary.

**RELATED DATA LIBRARIES**

AUS98 includes a cross-section library with 200 neutron and 37 photon groups and a fission product decay library with 869 fission products. Both libraries are based on ENDF/B-VI.

**2. CONTRIBUTOR**

Australian Nuclear Science and Technology Organisation, Lucas Heights, Australia.

**3. CODING LANGUAGE AND COMPUTER**

Fortran 77 and C; SGI and Sun UNIX workstations. (C00519MNYWS01)

**4. NATURE OF PROBLEM SOLVED**

AUS is a neutronics code system which may be used for calculations of a wide range of fission reactors, fusion blankets and other neutron applications. The present version, AUS98, has a nuclear cross section library based on ENDF/B-VI and includes modules which provide for reactor lattice calculations, one-dimensional transport calculations, multi-dimensional diffusion calculations, cell and whole reactor burnup calculations, and flexible editing of results. Calculations of multi-region resonance shielding, coupled neutron and photon transport, energy deposition, fission product inventory and neutron diffusion are combined within the one code system.

The major changes from the previous release, AUS87, are the inclusion of a cross-section library based on ENDF/B-VI, the addition of the POW3D multi-dimensional diffusion module, the addition of the MICBURN module for controlling whole reactor burnup calculations, and changes to the system as a consequence of moving from IBM mainframe computers to UNIX workstations.

**5. METHOD OF SOLUTION**

AUS98 is a modular system in which the modules are complete programs linked by a path given in the input stream. A simple path is simply a sequence of modules, but the path is actually preprocessed and compiled using the Fortran 77 compiler. This provides for complex module linking if required. Some of the modules included in AUS98 are:

MIRANDA Cross-section generation in a multi-region resonance subgroup calculation and preliminary group condensation.

ANAUSN One-dimensional discrete ordinates calculation.

ICPP Isotropic collision probability calculation in one dimension and for rod clusters.

POW3D Multi-dimensional neutron diffusion calculation including feedback-free kinetics.

AUSIDD One-dimensional diffusion calculation.

EDITAR Reaction-rate editing and group collapsing following a transport calculation.

CHAR Lattice and global burnup calculation.

MICBURN Control of global burnup calculation and fuel management using microscopic nuclide cross sections.

BURNMAC Global burnup calculation and fuel management using macroscopic material cross sections.

AUSED Cross-section editing and maintenance.

ORNL Forming cross sections for standard transport codes such as DORT and KENO.

MERGEL Merging of cross sections files.

PLOTXS Interactive plotting of cross section files.

AUSPLOT Interactive plotting of fluxes and reaction rates following a transport calculation.

**6. RESTRICTIONS OR LIMITATIONS**

None noted.

**7. TYPICAL RUNNING TIME**

Running times on a Silicon Graphics Power Challenge vary from one second for a simple cell calculation to one or two minutes for a three dimensional diffusion equation. The longest running test case which includes six three dimensional diffusion calculation took 2.2 minute.

**8. COMPUTER HARDWARE REQUIREMENTS**

AUS98 is operable on SGI workstations under IRIX 6.4, Sun workstations under SunOS5.6, and should be operable on any UNIX workstation.

**9. COMPUTER SOFTWARE REQUIREMENTS**

Compilation of AUS98 requires a Fortran 77 compiler and an ANSI C standard compiler. Execution also requires a Fortran 77 compiler. The AUSPLOT module, which is a useful but not essential part of AUS98, requires a Tcl interpreter with Tk such as WISHX and the GNUPLOT interactive plotting program.

**10. REFERENCES**

G. S. Robinson and B. V. Harrington, "AUS98 - The 1998 Version of the AUS Modular Neutronics Code System," ANSTO/E734 (July 1998).

B. V. Harrington, J. P. Pollard, and J. M. Barry, "POW3D - Neutron Diffusion Module of the AUS System, A User's Manual,"ANSTO/E726 (November 1996).

G. S. Robinson, "Generation and Validation of a Cross Section Library Based on ENDF/B-VI for the AUS Neutronics Code System," ANSTO/E712 (December 1993).

G. S. Robinson, "AUS Module MIRANDA - A Data Preparation Code Based on Multiregion Resonance Theory," ANSTO/E410 (July 1977).

**11. CONTENTS OF CODE PACKAGE**

Included are the referenced documents and a CD-Rom with a Unix tar file which contains source code for AUS98 and auxiliary programs, the two data libraries, sample problem input and output, and an installation script.

**12. DATE OF ABSTRACT**

December 1987, revised July 1999.

**KEYWORDS: ** CELL CALCULATIONS; COLLISION PROBABILITY; CTR; DIFFUSION
THEORY; DISCRETE ORDINATES; GAMMA-RAY; MODULAR SYSTEM;
MULTIGROUP; NEUTRON; REACTOR PHYSICS