# UPuZr Anisotropic Swelling Eigenstrain

This model accounts for the anisotropic swelling effect in UPuZr metal fuel.

## Description

This model, UPuZrAnisotropicSwellingEigenstrain, computes a anisotropic strain based on the model originally proposed by Ogata and Yokoo (1999). The strain is computed based on an empirically derived anisotropy factor which has been calibrated to a specific set of experimental data. Once that value is determined the radial eigenstrain imposed on the fuel is calculated as (1) where is the initial gap between the clad and fuel and is the as-fabricated cold radius of pellet, both in meters.

## Example Input Syntax


[./fuel_anisotropic_swelling_strain]
type = UPuZrAnisotropicSwellingEigenstrain
block = fuel
fuel_pin_geometry = fuel_pin_geometry
anisotropy_factor = 0.50
eigenstrain_name = fuel_anisotropic_swelling_strain
[../]
(test/tests/anisotropic_swelling/anisotropic_swelling_eigenstrain.i)

The eigenstrain_name parameter value must also be set for the strain calculator, and an example parameter setting is shown below:

[./gps_fuel]
out_of_plane_strain_name = strain_yy
fuel_pin_geometry = fuel_pin_geometry
strain = finite
block = fuel
eigenstrain_names = 'fuel_anisotropic_swelling_strain'
decomposition_method = EigenSolution
use_displaced_mesh = true
[../]
(test/tests/anisotropic_swelling/anisotropic_swelling_eigenstrain.i)

## Input Parameters

• eigenstrain_nameMaterial property name for the eigenstrain tensor computed by this model. IMPORTANT: The name of this property must also be provided to the strain calculator.

C++ Type:std::string

Description:Material property name for the eigenstrain tensor computed by this model. IMPORTANT: The name of this property must also be provided to the strain calculator.

### Required Parameters

• axial_axis1Coordinate axis of the axial direction of the fuel stack (0, 1, or 2 for x, y, or z

Default:1

C++ Type:unsigned int

Description:Coordinate axis of the axial direction of the fuel stack (0, 1, or 2 for x, y, or z

• computeTrueWhen false, MOOSE will not call compute methods on this material. The user must call computeProperties() after retrieving the Material via MaterialPropertyInterface::getMaterial(). Non-computed Materials are not sorted for dependencies.

Default:True

C++ Type:bool

Description:When false, MOOSE will not call compute methods on this material. The user must call computeProperties() after retrieving the Material via MaterialPropertyInterface::getMaterial(). Non-computed Materials are not sorted for dependencies.

• base_nameOptional parameter that allows the user to define multiple mechanics material systems on the same block, i.e. for multiple phases

C++ Type:std::string

Description:Optional parameter that allows the user to define multiple mechanics material systems on the same block, i.e. for multiple phases

• pellet_diameterAs fabricated cold diameter of pellet in meters

C++ Type:double

Description:As fabricated cold diameter of pellet in meters

• fuel_pin_geometryName of the UserObject that reads the pin geometry from the mesh.

C++ Type:UserObjectName

Description:Name of the UserObject that reads the pin geometry from the mesh.

• boundaryThe list of boundary IDs from the mesh where this boundary condition applies

C++ Type:std::vector

Description:The list of boundary IDs from the mesh where this boundary condition applies

• anisotropy_factor0Anisotropy factor as obtained from calibration plot

Default:0

C++ Type:double

Description:Anisotropy factor as obtained from calibration plot

• blockThe list of block ids (SubdomainID) that this object will be applied

C++ Type:std::vector

Description:The list of block ids (SubdomainID) that this object will be applied

### 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.

• 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.

• seed0The seed for the master random number generator

Default:0

C++ Type:unsigned int

Description:The seed for the master random number generator

• implicitTrueDetermines whether this object is calculated using an implicit or explicit form

Default:True

C++ Type:bool

Description:Determines whether this object is calculated using an implicit or explicit form

• constant_onNONEWhen ELEMENT, MOOSE will only call computeQpProperties() for the 0th quadrature point, and then copy that value to the other qps.When SUBDOMAIN, MOOSE will only call computeSubdomainProperties() for the 0th quadrature point, and then copy that value to the other qps. Evaluations on element qps will be skipped

Default:NONE

C++ Type:MooseEnum

Description:When ELEMENT, MOOSE will only call computeQpProperties() for the 0th quadrature point, and then copy that value to the other qps.When SUBDOMAIN, MOOSE will only call computeSubdomainProperties() for the 0th quadrature point, and then copy that value to the other qps. Evaluations on element qps will be skipped

• output_propertiesList of material properties, from this material, to output (outputs must also be defined to an output type)

C++ Type:std::vector

Description:List of material properties, from this material, to output (outputs must also be defined to an output type)

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

Default:none

C++ Type:std::vector

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

## References

1. T. Ogata and T. Yokoo. Devlopment and Validation of ALFUS: An Irradiation Behavior Analysis Code for Metallic Fast Reactor Fuels. Journal of Nuclear Technology, 128(1):113â€“123, 1999.[BibTeX]