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Fuel Analysis under Steady-state and Transients (FAST) a Fortran-based computer code that calculates the steady-state and transient response of light-water reactor fuel rods during long-term in-reactor burnup, up to and including dry storage conditions. The code calculates the temperature, pressure, and deformation of a fuel rod as functions of time-dependent fuel rod power and coolant boundary conditions.

The FRAPCON code calculates the steady-state response of light water reactor fuel rods during long-term burnup. The code calculates the temperature, pressure, and deformation of a fuel rod as functions of time-dependent fuel rod power and coolant boundary conditions. FRAPCON is designed to generate initial conditions for transient fuel rod analysis by the FRAPTRAN computer code

The FRAP installation package for SNAP includes both the FAST and FRAPTRAN plug-ins. The legacy FRAPCON plug-in has been superceded by the FAST plug-in. The FAST plug-in will open legacy FRAPCON models and can be used to run FRAPCON.

Change Log

Version 3.0.0 - Released 11/21/2017:

  • The new FAST plug-in provides support for the FAST and FRAPCON analysis codes. Some of the new features provided by the plug-in are:
    • FAST input specification IO & editing support - Import and export routines were added for handling the new FAST input specification. Intuitive editors were added to facilitate the specification of FAST input values.
    • Validation Window Implementation - This new display helps identify ASCII values written to the ASCII viewer and Validation Window. Selecting values in these views provides detailed descriptions and provides an option for a quick edit of selected data.
    • Power History and Boundary Cases - New cases behavior was added for supporting the generation of sets of power history and boundary data. Job stream numeric parametric combinations/tabular parametrics can be used to quickly guide which of the set cases to submit.
    • FAST and FRAPCON job streams - Job stream job steps are provided for both FAST and FRAPCON. These steps can be used in combination with the selected model input version.
    • FRAPCON and FAST input versions - Code version support has been added for both FRAPCON and FAST input formats. The input version can be selected from either the ASCII import selector or Model Options Flavor/Version editors.
    • Direct loading of FRAPCON plug-in MED model files - The FAST model load logic will handle either FRAPCON or FAST med files. Legacy med files will open set to the appropriate FRAPCON code version the file was saved with.
  • The following updates were made to the FRAPTRAN plug-in:
    • The ‘!’ comment character will now be properly handled by the ASCII import routines.
    • Added support for the FRAPTRAN developmental refabrication input for restart calculations. A new bottom/top axial node data pair is provided in Model Options for defining the range of nodes which corresponds to the incoming FRAPCON nodes. A model check was added to ensure the number of nodes defined matches the FRAPTRAN naxn value.