# Uvar element = document.getElementById("moose-equation-7958823d-5f8c-4e54-b541-ccd9d4917ff5");katex.render("_3", element, {displayMode:false,throwOnError:false});Sivar element = document.getElementById("moose-equation-085463d1-4b5b-4656-b38b-45afa23bfd9c");katex.render("_2", element, {displayMode:false,throwOnError:false}); Tricubic Interpolation User Object

Performs tricubic interpolation in temperature, temperature gradient, and burnup (fission density) to determine the degradation to the thermal conductivity and gaseous swelling of U3Si2 fuel.

## Description

The U3Si2TricubicInterpolationUserObject performs tricubic interpolation using the data contained in the input comma separated value (.csv) files for calculations utilized by ThermalSilicideFuel and U3Si2VolumetricSwellingEigenstrain.

### Required CSV Files

The user must specify six input csv files for the algorithm.

The first three represent the grid points of the tricubic calculation for which values are known. These grid points are for temperature, temperature gradient, and fission density. These files must be in ROW format consisting of a single row of data with each column delimited. The units of the values in the files should be K for temperature, K/mm for temperature gradient and fissions/cm with the power of 10 removed (i.e., a fission density of 2.010 would be input as 2.0).

The last three files represent the values of grain boundary coverage (FCOV), gaseous swelling strain due to intragranular bubbles (GSWb), and total gaseous swelling (GSW) for a given combination of temperature, temperature gradient and fission density. These files must have as many rows as the product of the number of columns in the temperature_grid_points file and number of columns in the temperature_gradient_grid_points file. The number of columns in these three files should equal the number of columns in the fission_density_grid_points file.

## Example Input Syntax


[UserObjects]
type = U3Si2TricubicInterpolationUserObject
execute_on = 'initial nonlinear'
temperature_grid_points_file = temperature.csv
fission_density_grid_points_file = fission_density.csv
grain_boundary_coverage_file = fcov.csv
intragranular_gaseous_swelling_file = gswb.csv
total_gaseous_swelling_file = gsw.csv
[../]
[]
(test/tests/thermalSilicideFuel/thermalU3Si2_argonne.i)

## Input Parameters

• fission_density_grid_points_fileFile holding data for the fission density (burnup) grid points to be used with the tricubic interpolation. Units are fissions/cm^3 with the trailing 10^21 removed (i.e., 2.5e20^21 would be 2.5).

C++ Type:FileName

Description:File holding data for the fission density (burnup) grid points to be used with the tricubic interpolation. Units are fissions/cm^3 with the trailing 10^21 removed (i.e., 2.5e20^21 would be 2.5).

• intragranular_gaseous_swelling_fileFile holding data for the gaseous swelling strain due to intragranular bubbles (GSWb) to be used with the tricubic interpolation calculation.

C++ Type:FileName

Description:File holding data for the gaseous swelling strain due to intragranular bubbles (GSWb) to be used with the tricubic interpolation calculation.

• total_gaseous_swelling_fileFile holding data for the total gaseous swelling strain (GSW) to be used with the tricubic interpolation calculation.

C++ Type:FileName

Description:File holding data for the total gaseous swelling strain (GSW) to be used with the tricubic interpolation calculation.

• temperature_gradient_grid_points_fileFile holding data for the temperature gradient grid points to be used with the tricubic interpolation.

C++ Type:FileName

Description:File holding data for the temperature gradient grid points to be used with the tricubic interpolation.

• grain_boundary_coverage_fileFile holding data for the grain boundary converage (FCOV) to be used with the tricubic interpolation calculation.

C++ Type:FileName

Description:File holding data for the grain boundary converage (FCOV) to be used with the tricubic interpolation calculation.

• temperature_grid_points_fileFile holding data for temperature grid points to be used with the tricubic interpolation.

C++ Type:FileName

Description:File holding data for temperature grid points to be used with the tricubic interpolation.

### 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.

### Optional Parameters

• 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.

• enableTrueSet the enabled status of the MooseObject.

Default:True

C++ Type:bool

Description:Set the enabled status of the MooseObject.

• 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).

• 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.

• force_preauxFalseForces the GeneralUserObject to be executed in PREAUX

Default:False

C++ Type:bool

Description:Forces the GeneralUserObject to be executed in PREAUX