1. NAME AND TITLE
REBUS-3/VARIANT8.0: Code System for Analysis of Fast Reactor Fuel Cycles.
Auxiliary Codes: DIF3D 8.0: Solves 1-D, 2-D, and 3-D finite-difference diffusion theory problems.
VARIANT 8.0: Solves VARIational Anisotropic Nodal Transport problems.
2. CONTRIBUTOR
Argonne National Laboratory, Argonne, Illinois.
3. CODING LANGUAGE AND COMPUTER
Fortran 77 and C; Sun SparcStation, IBM RS/6000 (C00653/MNYWS/01). The CCC-708/REBUS-PC 1.4 code system runs under both Windows and Linux operating systems on Intel personal computers.
4. NATURE OF PROBLEM SOLVED
REBUS-3 is a system of codes designed for the analysis of fast reactor fuel cycles. Two basic types of analysis problems are solved: 1) the infinite-time, or equilibrium, conditions of a reactor operating under a fixed fuel management scheme, or 2) the explicit cycle-by-cycle, or nonequilibrium operation of a reactor under a specified periodic or non-periodic fuel management program. For the equilibrium type problems, the code uses specified external fuel supplies to load the reactor. Optionally, reprocessing may be included in the specification of the external fuel cycle and discharged fuel may be recycled back into the reactor. For non-equilibrium cases, the initial composition of the reactor core may be explicitly specified or the core may be loaded from external feeds and discharged fuel may be recycled back into the reactor as in equilibrium problems.
Four types of search procedures may be carried out in order to satisfy user-supplied constraints: 1) adjustment of the reactor burn cycle time to achieve a specified discharge burnup, 2) adjustment of the fresh fuel enrichment to achieve a specified multiplication constant at a specified point during the burn cycle, 3) adjustment of the control poison density to maintain a specified value of the multiplication constant throughout the reactor burn cycle, and 4) adjustment of the reactor burn cycle time to achieve a specified value of the multiplication constant at the end of the burn step.
REBUS will handle both equilibrium and non-equilibrium problems using a number of different core geometries including triangular and hexagonal mesh. The neutronics solution may be obtained using finite difference, nodal diffusion-theory and variational nodal transport methods. Fixed source depletion may be done with the three solution methods. Other features include: fully automatic restart capability, no restrictions on number of neutron energy groups, and general external cycle with no restrictions on number of external feeds, reprocessing plants, etc. Fuel management is completely general for nonequilibrium problems. Microscopic cross sections are permitted to vary as a function of the atom density of various reference isotopes in the problem as appropriate for soft spectrum systems. The user may specify control rod positions at each time node in the problem. A number of relational database datasets containing various types of summary results are available for use in tailoring reports.
This is a standalone and expanded version of the modular REBUS-3 code system described in Ref. 1 and 2. REBUS-3 is fully compatible with the CCCC coding standards and interface data sets. It utilizes the DIF3D nodal option of DIF3D and VARIANT 8.0 (CCC-649) codes to obtain the neutronics solution. However, this CCC-653 distribution does not include the DIF3D main program which is in the CCC-649 DIF3D package.
5. METHOD OF SOLUTION
The total reactor burn cycle time is divided into one or more subintervals, the number of which is specified by the user. An explicit burnup is performed in each region of the reactor over each of these subintervals using the average reaction rates over the subinterval. These average reaction rates are based on fluxes obtained from an explicit 1-, 2-, or 3-dimensional diffusion theory neutronics solution computed at both the beginning and end of the subinterval. The transmutation equations are solved by the matrix-exponential technique. The isotopes to be considered in the burnup equations, as well as their transmutation reactions, are specified by the user.
6. RESTRICTIONS OR LIMITATIONS
None noted.
7. TYPICAL RUNNING TIME
Three to thirty minutes or longer depending on size and complexity of problem and machine utilized.
8. COMPUTER HARDWARE REQUIREMENTS
The modular version of the code is in production use at Argonne National Laboratory on Unix Workstations Sun SPARCStation. External data storage must be available for approximately 40 scratch and interface files. Fourteen of these files are random access scratch files (grouped into 6 file groups), and the remainder are sequential access files with formatted or unformatted record types.
9. COMPUTER SOFTWARE REQUIREMENTS
No special requirements are made on the operating system (SOLARIS 2.6 and 2.7 for SPARCStations and AIX 4.3.3 on the IBM). The included installation procedure requires Fortran 77 and C compilers. With modifications the program can be executed entirely in FORTRAN. Optional dynamic memory allocation and timing routines supplied from host machine libraries or code in "C" may be used on Unix workstations. Although developed on the Cray and IBM 30xx, the current version is tailored to Sun SparcStations and IBM AIX RS/6000.
10. REFERENCES
a) included in the documentation on CD in file DOC/C653.PDF:
B. J. Toppel, "The Fuel Cycle Analysis Capability REBUS-3," ANL-83-2 (March 1983 revised October 26, 1990) also included in PDF/REBUS-3_document.pdf.
R. P. Hosteny, "The ARC System Fuel Cycle Analysis Capability, REBUS-2," ANL-7721 (October 1978).
b) other useful documentation distributed in subdirectory rebus3/PDF:
G. Palmiotti, E. E. Lewis, and C. B. Carrico, "VARIANT: VARIational Anisotropic Nodal Transport for Multidimensional Cartesian and Hexagonal Geometry Calculation," ANL-95/40, (October 1995) in file PDF/Var.manual.pdf.
K. L. Derstine, "DIF3D: A Code to Solve One-, Two-, and Three-Dimensional Finite-Difference Diffusion Theory Problems," ANL-82-64 (April 1984) in directory PDF/D3D.
R. D. Lawrence, "The DIF3D Nodal Neutronics Option for Two-and Three-Dimensional Diffusion Theory Calculations in Hexagonal Geometry," ANL-83-1 (March 1983) in directory PDF/D3DN.
C. H. Adams, et.al., "The Utility Subroutine Package Used by Applied Physics Division Export Codes," ANL-83-3 (May 1992) in file PDF/anl833.pdf.
c) background information not included in the package
R. D. O'Dell, "Standard Interface Files and Procedures for Reactor Physics Codes, Version IV," UC-32 (September 1977).
11. CONTENTS OF CODE PACKAGE
Included are referenced documents in (10.a & b) on one CD which contains a UNIX tar file including scripts, source code, sample problem data, sample problem output, code dependent BCD and binary card-image file descriptions, and Readme.txt.
12. DATE OF ABSTRACT
May 1997, revised April 2001, June 2002.
KEYWORDS: DEPLETION; FUEL MANAGEMENT; BURNUP; CCCC INTERFACE FORMAT; DIFFUSION THEORY; CRITICALITY CALCULATIONS; REACTOR PHYSICS; COMPLEX GEOMETRY; WORKSTATION