Argonne National Laboratory

Nuclear Science and Engineering

REBUS

A fuel cycle analysis code based upon the DIF3D solver

Standard Code Description

  1. Coding Language and Computing Platforms
    Fortran source code for Linux and Macintosh
  2. Description of Purpose
    REBUS has been maintained by Argonne since the early 1960s to support its reactor design mission. That software transitioned from the original REBUS to REBUS-2 in the mid 1970s and to REBUS-3 in the mid 1980s. Since then REBUS has gone through many revisions to the current release version. The present release version is consistent with the progression of DIF3D, the base flux solver that REBUS is built upon. The name REBUS refers to a pictorial based puzzle as the original developers were inspired by having to track thousands of unique fuel assemblies as they are inserted into the reactor, depleted, shuffled, discharged, and reprocessed.

    REBUS was designed around the DIF3D code and thus is primarily based upon a semi-structured grid geometry using the exact same binary interface files and variable naming scheme as in DIF3D. Over its extensive history, REBUS has been applied to numerous fast and thermal spectrum reactor analysis projects. The present REBUS capability can perform fuel cycle analysis on all of the DIF3D geometries: slab and cylindrical 1D domains, Cartesian, hexagonal, and R-Z two-dimensional domains, and Cartesian, hexagonal, triangular-Z, and R-Z-θ three-dimensional domains.

    By design, REBUS was intended to allow the user to simply and rapidly compute the equilibrium state of a repetitive fuel management scheme. This capability allows the user to search for the required fissile fuel enrichment, using a given repetitive fuel management scheme, such that the desired core criticality is met at a user specified time point. To accomplish this, the software has fuel fabrication and reprocessing plant modeling capabilities that allow multiple sources of feed materials. REBUS can also search for the cycle length and adjust the enrichment to meet the specified criticality constraints. In addition to the equilibrium option, REBUS also has a conventional non-equilibrium option which allows the same type of searches as in the equilibrium option but actually models the discrete fuel management/cycle operations in the reactor.

    The total reactor burn cycle time is divided into one or more subintervals, the number of which is specified by the user. An explicit nuclide depletion computation 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 DIF3D computed at both the beginning and end of the subinterval. The nuclide 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.
  3. Typical Running Time
    The run time strongly depends on the time spent in DIF3D. The depletion calculations internal to REBUS take less than a few minutes of total computational time while DIF3D can drive the total computation time from minutes to days depending upon the size of the problem.
  4. References
    1. B. J. Toppel, ​“The Fuel Cycle Analysis Capability REBUS-3,” ANL-83-2, Argonne National Laboratory (March 1983).
    2. R. P. Hosteny, ​“The ARC System Fuel Cycle Analysis Capability, REBUS-2,” ANL-7721, Argonne National Laboratory (October 1978).
    3. R. Douglas O’Dell, ​“Standard Interface Files and Procedures for Reactor Physics Codes, Version IV,” UC-32, Los Alamos Scientific Laboratory (September 1977).
    4. K. L. Derstine, ​“DIF3D: A Code to Solve One-, Two-, and Three-Dimensional Finite-Difference Diffusion Theory Problems,” ANL-82-64, Argonne National Laboratory (April 1984).
    5. R. D. Lawrence, ​“The DIF3D Nodal Neutronics Option for Two- and Three-Dimensional Diffusion Theory Calculations in Hexagonal Geometry,” ANL-83-1, Argonne National Laboratory (March 1983).
    6. W. S. Yang, M. A. Smith, ​“Theory Manual for the Fuel Cycle Analysis Code REBUS,” ANL/NE-19/21, Argonne National Laboratory (2020).
  5. Primary Authors
    1. B. J. Toppel, Argonne National Laboratory
    2. W. S. Yang, University of Michigan
  6. Materials Available
    The source code and compilation instructions are provided. Precompiled executables for Linux and Macintosh are also included. The source code and executables for all utility programs associated with the Argonne Reactor Code system are also included. Documentation on all solvers in DIF3D and REBUS is provided along with all of the verification test cases for DIF3D and REBUS. Contact nera-​software@​anl.​gov for licensing and distribution information.
  7. Sponsor
    U.S. Department of Energy, Office of Nuclear Energy