FINIX - Fuel behavior model and interface for multiphysics applications: Code documentation for version 0.17.12

Henri Loukusa, Ville Valtavirta

    Research output: Book/ReportReport

    272 Downloads (Pure)


    The FINIX fuel behavior code has been updated to version 0.17.12. In the new version several steady-state models have been implemented, and a new steady-state temperature solver has been developed. The new steady state models are a fission gas release model, fuel grain growth model, fuel swelling and densification models, a cladding creep model, a cladding failure model and a radial power distribution model.

    The FINIX code has been designed to provide a fuel behavior module for other calculation codes in multiphysics simulations. The intended use is the improvement of fuel behavior description in neutronics, thermal hydraulics and reactor dynamics codes, without having to employ full-scale fuel performance codes. FINIX couples with the host code on a source code level, and provides an interface of functions that can be used to access the fuel behavior model from the host code. At VTT, FINIX has been integrated into the Monte Carlo reactor physics code Serpent 2, and reactor dynamics codes TRAB-1D, TRAB3D and HEXTRAN.

    FINIX consists of several interconnected models that describe the thermo-mechanical behavior of the fuel rod. FINIX solves the transient or steady-state heat equation, with couplings to the cladding and pellet mechanical behavior through the gap conductance and pressure. Publicly available experimental correlations are used for the material properties, and simple models for the heat transfer from the cladding to the coolant have been included.

    FINIX has been verified against the FRAPTRAN and FRAPCON fuel performance codes in RIA and steady-state scenarios, and compared against experimental Halden reactor data. Results indicate good agreement with the FRAPTRAN and FRAPCON codes and experimental measurements. Limitations of the present version in the simulated scenarios have also been identified.
    Original languageEnglish
    PublisherVTT Technical Research Centre of Finland
    Number of pages82
    Publication statusPublished - 2017
    MoE publication typeD4 Published development or research report or study

    Publication series

    SeriesVTT Research Report


    • fuel behaviour modelling
    • FINIX


    Dive into the research topics of 'FINIX - Fuel behavior model and interface for multiphysics applications: Code documentation for version 0.17.12'. Together they form a unique fingerprint.

    Cite this