COUPLING THE CORE ANALYSIS PROGRAM DeCART TO THE FUEL PERFORMANCE APPLICATION BISON

The 3D neutron transport and core analysis program DeCART was coupled to the fuels performance application BISON to provide a higher fidelity tool for fuel performance simulation. This project is motivated by the desire to couple a high fidelity core analysis program (based on the method of characteristics) to a high fidelity fuel performance program, both of which can simulate 3D problems. DeCART provides sub-pin level resolution of the multigroup neutron flux, with resonance treatment, during burnup or a fast transient. BISON implicitly solves coupled thermomechanical equations for the fuel on a sub-millimeter level finite element mesh. A method was developed for mapping the fission rate density and fast neutron flux from DeCART to BISON. Multiple depletion cases were run with one-way data transfer from DeCART to BISON. The one-way data transfer of fission rate density is shown to agree with the fission rate density obtained from an internal Lassman-style model in BISON. One-way data transfer was also demonstrated in a 3D case in which azimuthal asymmetry was induced in the fission rate density profile of a fuel rod modeled in DeCART. Two-way data transfer was established by mapping the temperature distribution from BISON to DeCART. A Picard iterative algorithmmore » was developed for the loose coupling with two-way data transfer. (authors)« less