Radial Average Enthalpy

Uses radial temperature output from a LineValueSampler postprocessor to calculate radial average fuel enthalpy at given axial position for UO2 above 300 K

Description

RadialAverageEnthalpy calculates the radial average fuel enthalpy (J/kg) at a specified axial position in a radially symmetric fuel element.

Radial average fuel enthalpy is useful in assessing fuel performance and failure states for reactivity insertion accident (RIA) cases and may only be used with the RZ coordinate type. The Kerrisk's method to calculate enthalpy is only applicable for temperatures above 300 K, and currently only supports uranium oxide fuel types (fuel_type = UO2) Kerrisk and Clifton (1972).

A LineValueSampler VectorPostprocessor is set up to sample temperature at various radial positions (almost exclusively sort_by = x in radially symmetric 2D meshes) by specifying the start_point and end_point with string lists in the form 'x y z' executed at the end of a timestep.T

The user may specify the number of points to sample and LineValueSampler will interpolate between temperatures distributed on the mesh. The name of the LineValueSampler block must be used as the argument for the vectorpostprocessor parameter as shown in the input file example below. The argument for the r_dim parameter should correspond to the radial direction of the mesh geometry (this should be the same axis specified in sort_by).

warning:Corresponding Parameters

The LineValueSampler is necessary to pull in the temperature data required to calculate the radial average fuel enthalpy at a particular axial position. The r_dim and sort_by parameters in RadialAverageEnthalpy and LineValueSampler input blocks, respectively, must both be the same axis (almost always x).

To suppress CSV output of the LineValueSampler, add a separate output of type CSV and set enable = 0.

Example Input Syntax


[Postprocessors]
  [./radial_average_enthalpy]
    type = RadialAverageEnthalpy
    vectorpostprocessor = rad_temp
    r_dim = x
    fuel_type = UO2
  [../]
[]
(test/tests/radial_avg_fuel_enthalpy/radial_avg_enthalpy.i)

A LineValueSampler vector postprocessor is required to use the RadialAverageEnthalpy postprocessor. Example syntax for the LineValueSampler associated with the previous RadialAverageEnthalpy syntax example follows.


[VectorPostprocessors]
  [./rad_temp]
    type = LineValueSampler
    end_point = '0.005 0.000 0.0'
    start_point = '0.0 0.000 0.0'
    sort_by = x
    variable = temp
    execute_on = timestep_end
    num_points = 31
    outputs = dummy #this will prevent the VectorPostprocessor from outputing CSV files every timestep
  [../]
[]
(test/tests/radial_avg_fuel_enthalpy/radial_avg_enthalpy.i)

Input Parameters

  • fuel_typeType of fuel BISON is modeling

    C++ Type:std::string

    Description:Type of fuel BISON is modeling

  • r_dimThe name of the radial position variable

    C++ Type:std::string

    Description:The name of the radial position variable

  • vectorpostprocessorThe vectorpostprocessor whose values we use to calculate radial average fuel enthalpy

    C++ Type:VectorPostprocessorName

    Description:The vectorpostprocessor whose values we use to calculate radial average fuel enthalpy

Required Parameters

  • execute_onTIMESTEP_ENDThe list of flag(s) indicating when this object should be executed, the available options include NONE, INITIAL, LINEAR, NONLINEAR, TIMESTEP_END, TIMESTEP_BEGIN, FINAL, CUSTOM.

    Default:TIMESTEP_END

    C++ Type:ExecFlagEnum

    Description:The list of flag(s) indicating when this object should be executed, the available options include NONE, INITIAL, LINEAR, NONLINEAR, TIMESTEP_END, TIMESTEP_BEGIN, FINAL, CUSTOM.

  • oxy_to_metal_ratio2The ratio of oxygen to uranium in the fuel

    Default:2

    C++ Type:double

    Description:The ratio of oxygen to uranium in the fuel

  • temp_nametempThe name of the temperature variable

    Default:temp

    C++ Type:std::string

    Description:The name of the temperature variable

Optional Parameters

  • enableTrueSet the enabled status of the MooseObject.

    Default:True

    C++ Type:bool

    Description:Set the enabled status of the MooseObject.

  • use_displaced_meshFalseWhether or not this object should use the displaced mesh for computation. Note that in the case this is true but no displacements are provided in the Mesh block the undisplaced mesh will still be used.

    Default:False

    C++ Type:bool

    Description:Whether or not this object should use the displaced mesh for computation. Note that in the case this is true but no displacements are provided in the Mesh block the undisplaced mesh will still be used.

  • outputsVector of output names were you would like to restrict the output of variables(s) associated with this object

    C++ Type:std::vector

    Description:Vector of output names were you would like to restrict the output of variables(s) associated with this object

  • control_tagsAdds user-defined labels for accessing object parameters via control logic.

    C++ Type:std::vector

    Description:Adds user-defined labels for accessing object parameters via control logic.

  • allow_duplicate_execution_on_initialFalseIn the case where this UserObject is depended upon by an initial condition, allow it to be executed twice during the initial setup (once before the IC and again after mesh adaptivity (if applicable).

    Default:False

    C++ Type:bool

    Description:In the case where this UserObject is depended upon by an initial condition, allow it to be executed twice during the initial setup (once before the IC and again after mesh adaptivity (if applicable).

  • force_preauxFalseForces the GeneralUserObject to be executed in PREAUX

    Default:False

    C++ Type:bool

    Description:Forces the GeneralUserObject to be executed in PREAUX

Advanced Parameters

Input Files

References

  1. J. F. Kerrisk and D. G. Clifton. Smoothed values of the enthalpy and heat capacity of uo2. Nuclear Technology, 16(3):531–535, 1972.[BibTeX]