OpenMCCellTransform

UserObject that applies either translation or rotation on one or more OpenMC cells. The transform is driven by a transform array of three MOOSE postprocessors/scalar values

Description

This user object can be used to either translate or rotate an openmc.Universe which is the fill of an openmc.Cell.

warning:The specified transformation is only applied to the universe which fills the cell.

This userobject doesn't translate or rotate the surfaces of the specified cell. Instead, the given transform will be used to shift/rotate the universe fill. Note that it is possible to create undesired void regions with a poorly defined cell/universe/transformation combination, which may result in lost particles. If you want to use moving mesh capabilities for general cell surfaces, consider using the MoabSkinner with DAGMC geometries instead.

Example Input Syntax

To translate a universe, the transform array takes ( $var element = document.getElementById("moose-equation-735d7277-1228-4fb5-bb92-3c2236aa29b2");katex.render("\\Delta x", element, {displayMode:false,throwOnError:false});$ , $var element = document.getElementById("moose-equation-46967dd2-8592-4c4b-a5e2-38a0902b34fd");katex.render("\\Delta y", element, {displayMode:false,throwOnError:false});$ , $var element = document.getElementById("moose-equation-633617af-9522-4d7f-b58b-2b1ade75a518");katex.render("\\Delta z", element, {displayMode:false,throwOnError:false});$ ) translations. Below is an example which will translate the universe inside a specified OpenMC cell:

[UserObjects<<<{"href": "../../syntax/UserObjects/index.html"}>>>]
  [translate_cells]
    type = OpenMCCellTransform<<<{"description": "UserObject that applies either translation or rotation on one or more OpenMC cells. The transform is driven by a transform array of three MOOSE postprocessors/scalar values", "href": "OpenMCCellTransform.html"}>>>
    transform_type<<<{"description": "Type of transform to apply: 'translation' (dx,dy,dz) or 'rotation'(\u03c6, \u03b8, \u03c8) in degrees, where the angles are the rotations about the x, y, and z axes, respectively."}>>> = 'translation'
    vector_value<<<{"description": "An array of three values/postprocessors. For translation this array expects (dx, dy, dz) in mesh units. For rotation this array expects '\u03c6, \u03b8, \u03c8' in degrees."}>>> = 'shift_x shift_y 0'
    cell_ids<<<{"description": "List of OpenMC cell IDs whose filled universes will be transformed."}>>> = '2011'
    execute_on<<<{"description": "The list of flag(s) indicating when this object should be executed. For a description of each flag, see https://mooseframework.inl.gov/source/interfaces/SetupInterface.html."}>>> = 'timestep_begin'
  []
[]

To rotate a universe, the transform array takes ( $var element = document.getElementById("moose-equation-d4c132a4-c00c-4c57-92fd-fd4549d02707");katex.render("\\phi", element, {displayMode:false,throwOnError:false});$ , $var element = document.getElementById("moose-equation-3e390f39-5131-41d0-ae9d-6d4fa986d376");katex.render("\\theta", element, {displayMode:false,throwOnError:false});$ , $var element = document.getElementById("moose-equation-bedeb47c-c516-4795-8dc2-204738474dad");katex.render("\\psi", element, {displayMode:false,throwOnError:false});$ ) which are the rotation angles in degrees about x, y, and z axes. Below is an example which will rotate the universe inside a specified OpenMC cell:

[UserObjects<<<{"href": "../../syntax/UserObjects/index.html"}>>>]
  [rotate_cells]
    type = OpenMCCellTransform<<<{"description": "UserObject that applies either translation or rotation on one or more OpenMC cells. The transform is driven by a transform array of three MOOSE postprocessors/scalar values", "href": "OpenMCCellTransform.html"}>>>
    transform_type<<<{"description": "Type of transform to apply: 'translation' (dx,dy,dz) or 'rotation'(\u03c6, \u03b8, \u03c8) in degrees, where the angles are the rotations about the x, y, and z axes, respectively."}>>> = 'rotation'
    vector_value<<<{"description": "An array of three values/postprocessors. For translation this array expects (dx, dy, dz) in mesh units. For rotation this array expects '\u03c6, \u03b8, \u03c8' in degrees."}>>> = '0 0 psi'
    cell_ids<<<{"description": "List of OpenMC cell IDs whose filled universes will be transformed."}>>> = '2011'
    execute_on<<<{"description": "The list of flag(s) indicating when this object should be executed. For a description of each flag, see https://mooseframework.inl.gov/source/interfaces/SetupInterface.html."}>>> = 'timestep_begin'
  []
[]

Input Parameters

cell_idsList of OpenMC cell IDs whose filled universes will be transformed.
C++ Type:std::vector<int>
Controllable:No
Description:List of OpenMC cell IDs whose filled universes will be transformed.
vector_valueAn array of three values/postprocessors. For translation this array expects (dx, dy, dz) in mesh units. For rotation this array expects 'φ, θ, ψ' in degrees.
C++ Type:std::vector<PostprocessorName>
Unit:(no unit assumed)
Controllable:No
Description:An array of three values/postprocessors. For translation this array expects (dx, dy, dz) in mesh units. For rotation this array expects 'φ, θ, ψ' in degrees.

Required Parameters

transform_typetranslationType of transform to apply: 'translation' (dx,dy,dz) or 'rotation'(φ, θ, ψ) in degrees, where the angles are the rotations about the x, y, and z axes, respectively.
Default:translation
C++ Type:MooseEnum
Options:translation, rotation
Controllable:No
Description:Type of transform to apply: 'translation' (dx,dy,dz) or 'rotation'(φ, θ, ψ) in degrees, where the angles are the rotations about the x, y, and z axes, respectively.

Optional Parameters

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
Controllable:No
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).
execute_onTIMESTEP_ENDThe list of flag(s) indicating when this object should be executed. For a description of each flag, see https://mooseframework.inl.gov/source/interfaces/SetupInterface.html.
Default:TIMESTEP_END
C++ Type:ExecFlagEnum
Options:XFEM_MARK, NONE, INITIAL, LINEAR, LINEAR_CONVERGENCE, NONLINEAR, NONLINEAR_CONVERGENCE, POSTCHECK, TIMESTEP_END, TIMESTEP_BEGIN, MULTIAPP_FIXED_POINT_END, MULTIAPP_FIXED_POINT_BEGIN, MULTIAPP_FIXED_POINT_CONVERGENCE, FINAL, CUSTOM, TRANSFER
Controllable:No
Description:The list of flag(s) indicating when this object should be executed. For a description of each flag, see https://mooseframework.inl.gov/source/interfaces/SetupInterface.html.
execution_order_group0Execution order groups are executed in increasing order (e.g., the lowest number is executed first). Note that negative group numbers may be used to execute groups before the default (0) group. Please refer to the user object documentation for ordering of user object execution within a group.
Default:0
C++ Type:int
Controllable:No
Description:Execution order groups are executed in increasing order (e.g., the lowest number is executed first). Note that negative group numbers may be used to execute groups before the default (0) group. Please refer to the user object documentation for ordering of user object execution within a group.
force_postauxFalseForces the UserObject to be executed in POSTAUX
Default:False
C++ Type:bool
Controllable:No
Description:Forces the UserObject to be executed in POSTAUX
force_preauxFalseForces the UserObject to be executed in PREAUX
Default:False
C++ Type:bool
Controllable:No
Description:Forces the UserObject to be executed in PREAUX
force_preicFalseForces the UserObject to be executed in PREIC during initial setup
Default:False
C++ Type:bool
Controllable:No
Description:Forces the UserObject to be executed in PREIC during initial setup

Execution Scheduling Parameters

control_tagsAdds user-defined labels for accessing object parameters via control logic.
C++ Type:std::vector<std::string>
Controllable:No
Description:Adds user-defined labels for accessing object parameters via control logic.
enableTrueSet the enabled status of the MooseObject.
Default:True
C++ Type:bool
Controllable:Yes
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
Controllable:No
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.

Advanced Parameters

prop_getter_suffixAn optional suffix parameter that can be appended to any attempt to retrieve/get material properties. The suffix will be prepended with a '_' character.
C++ Type:MaterialPropertyName
Unit:(no unit assumed)
Controllable:No
Description:An optional suffix parameter that can be appended to any attempt to retrieve/get material properties. The suffix will be prepended with a '_' character.
use_interpolated_stateFalseFor the old and older state use projected material properties interpolated at the quadrature points. To set up projection use the ProjectedStatefulMaterialStorageAction.
Default:False
C++ Type:bool
Controllable:No
Description:For the old and older state use projected material properties interpolated at the quadrature points. To set up projection use the ProjectedStatefulMaterialStorageAction.

Material Property Retrieval Parameters

Input Files

(test/tests/userobjects/openmc_cell_transform/multiple_cells/translate_cells.i)
(test/tests/userobjects/openmc_cell_transform/scaled.i)
(test/tests/userobjects/openmc_cell_transform/cells_shadow.i)
(test/tests/userobjects/openmc_cell_transform/translate_cells.i)
(test/tests/userobjects/openmc_cell_transform/rotate_cells.i)
(test/tests/userobjects/openmc_cell_transform/empty_cell_ids.i)

(test/tests/userobjects/openmc_cell_transform/translate_cells.i)

[Mesh]
  [pin]
    type = ConcentricCircleMeshGenerator
    num_sectors = 6
    radii = '1.0'
    rings = '3 3'
    has_outer_square = on
    pitch = 4.0
    preserve_volumes = yes
    smoothing_max_it = 3
  []
  [assembly]
    type = CartesianIDPatternedMeshGenerator
    inputs = 'pin'
    pattern = '0 0;
               0 0'
    assign_type = 'cell'
    id_name = 'pin_id'
  []
  [delete]
    # Only keeping block 1 (fuel pins) for this test
    type = BlockDeletionGenerator
    input = assembly
    block = 2
  []
  [extrude]
    type = AdvancedExtruderGenerator
    input = delete
    direction = '0 0 1'
    heights = '30'
    num_layers = 1
  []
  [translate]
    type = TransformGenerator
    input = extrude
    transform = TRANSLATE_CENTER_ORIGIN
    vector_value = '-12 12 0'
  []
[]


[GlobalParams]
  displacements = 'disp_x disp_y disp_z'
  use_displaced_mesh = true
[]

[Problem]
  type = OpenMCCellAverageProblem
  cell_level = 2
  verbose = true
  power = 100

  [Tallies]
    [heat]
      type = CellTally
      score = 'kappa_fission'
      block = '1'
    []
  []
[]

[AuxVariables]
  [disp_x]
    [AuxKernel]
        type = FunctionAux
        variable = disp_x
        function = disp_x_fn
        execute_on = 'timestep_begin'
    []
  []
  [disp_y]
    [AuxKernel]
        type = FunctionAux
        variable = disp_y
        function = disp_y_fn
        execute_on = 'timestep_begin'
    []
  []
  [disp_z]
  []
[]

[Functions]
  [disp_x_fn]
    type = ParsedFunction
    expression = '2*t'
  []
  [disp_y_fn]
    type = ParsedFunction
    expression = '2*t'
  []
[]

[Postprocessors]
  [shift_x]
    type = FunctionValuePostprocessor
    function = disp_x_fn
    execute_on = 'timestep_begin'
  []
  [shift_y]
    type = FunctionValuePostprocessor
    function = disp_y_fn
    execute_on = 'timestep_begin'
  []
  [k]
    type = KEigenvalue
  []
  [power]
    type = ElementIntegralVariablePostprocessor
    variable = kappa_fission
    block = '1'
  []
[]

[UserObjects]
  [translate_cells]
    type = OpenMCCellTransform
    transform_type = 'translation'
    vector_value = 'shift_x shift_y 0'
    cell_ids = '2011'
    execute_on = 'timestep_begin'
  []
[]

[Executioner]
  type = Transient
  num_steps = 2
[]

[Outputs]
  exodus = true
[]

(test/tests/userobjects/openmc_cell_transform/rotate_cells.i)

[Mesh]
  [pin]
    type = ConcentricCircleMeshGenerator
    num_sectors = 6
    radii = '1.0'
    rings = '3 3'
    has_outer_square = on
    pitch = 4.0
    preserve_volumes = yes
    smoothing_max_it = 3
  []
  [assembly]
    type = CartesianIDPatternedMeshGenerator
    inputs = 'pin'
    pattern = '0 0;
               0 0'
    assign_type = 'cell'
    id_name = 'pin_id'
  []
  [delete]
    # Only keeping block 1 (fuel pins) for this test
    type = BlockDeletionGenerator
    input = assembly
    block = 2
  []
  [extrude]
    type = AdvancedExtruderGenerator
    input = delete
    direction = '0 0 1'
    heights = '30'
    num_layers = 1
  []
  [translate]
    type = TransformGenerator
    input = extrude
    transform = TRANSLATE_CENTER_ORIGIN
    vector_value = '-12 12 0'
  []
[]


[GlobalParams]
  displacements = 'disp_x disp_y disp_z'
  use_displaced_mesh = true
[]

[Problem]
  type = OpenMCCellAverageProblem
  cell_level = 2
  verbose = true
  power = 100

  [Tallies]
    [heat]
      type = CellTally
      score = 'kappa_fission'
      block = '1'
    []
  []
[]

[AuxVariables]
  [disp_x]
    [AuxKernel]
        type = FunctionAux
        variable = disp_x
        function = disp_x_fn
        execute_on = 'timestep_begin'
        use_displaced_mesh = false
    []
  []
  [disp_y]
    [AuxKernel]
        type = FunctionAux
        variable = disp_y
        function = disp_y_fn
        execute_on = 'timestep_begin'
        use_displaced_mesh = false
    []
  []
  [disp_z]
  []
[]

[Functions]
  [psi_fn]
    type = ParsedFunction
    expression = '5*t'
  []
  [disp_x_fn]
    type = ParsedFunction
    expression = (cos(5*t*3.14159265359/180)-1)*x-sin(5*t*3.14159265359/180)*y
  []
  [disp_y_fn]
    type = ParsedFunction
    expression = sin(5*t*3.14159265359/180)*x+(cos(5*t*3.14159265359/180)-1)*y
  []
[]

[Postprocessors]
  [psi]
    type = FunctionValuePostprocessor
    function = psi_fn
    execute_on = 'timestep_begin'
  []
  [k]
    type = KEigenvalue
  []
  [power]
    type = ElementIntegralVariablePostprocessor
    variable = kappa_fission
    block = '1'
  []
[]

[UserObjects]
  [rotate_cells]
    type = OpenMCCellTransform
    transform_type = 'rotation'
    vector_value = '0 0 psi'
    cell_ids = '2011'
    execute_on = 'timestep_begin'
  []
[]

[Executioner]
  type = Transient
  num_steps = 2
[]

[Outputs]
  exodus = true
[]

(test/tests/userobjects/openmc_cell_transform/multiple_cells/translate_cells.i)

[Mesh]
  [pin]
    type = ConcentricCircleMeshGenerator
    num_sectors = 6
    radii = '1.0'
    rings = '3 3'
    has_outer_square = on
    pitch = 4.0
    preserve_volumes = yes
    smoothing_max_it = 3
  []
  [assembly]
    type = CartesianIDPatternedMeshGenerator
    inputs = 'pin'
    pattern = '0 0;
               0 0'
    assign_type = 'cell'
    id_name = 'pin_id'
  []
  [delete]
    # Only keeping block 1 (fuel pins) for this test
    type = BlockDeletionGenerator
    input = assembly
    block = 2
  []
  [extrude]
    type = AdvancedExtruderGenerator
    direction = '0 0 1'
    input = delete
    heights = '30'
    num_layers = '5'
  []
  [translate]
    type = TransformGenerator
    input = extrude
    transform = TRANSLATE_CENTER_ORIGIN
    vector_value = '-12 12 0'
  []
[]


[GlobalParams]
  displacements = 'disp_x disp_y disp_z'
  use_displaced_mesh = true
[]

[Problem]
  type = OpenMCCellAverageProblem
  cell_level = 2
  verbose = true
  power = 100

  [Tallies]
    [heat]
      type = CellTally
      score = 'kappa_fission'
      block = '1'
    []
  []
[]

[AuxVariables]
  [disp_x]
    [AuxKernel]
        type = FunctionAux
        variable = disp_x
        function = disp_right_fn
    []
  []
  [disp_y]
    [AuxKernel]
        type = FunctionAux
        variable = disp_y
        function = disp_top_fn
    []
  []
  [disp_z]
  []
[]

[Functions]
  [disp_top_fn]
    type = ParsedFunction
    expression = 'if(t>1,if(y>0,2*t,0),0)'
  []
  [disp_right_fn]
    type = ParsedFunction
    expression = 'if(t>1,if(x>0,t,0),0)'
  []
[]

[Postprocessors]
  [shift_top_row]
    type = FunctionValuePostprocessor
    function = disp_top_fn
  []
  [shift_right_column]
    type = FunctionValuePostprocessor
    function = disp_right_fn
  []
  [k]
    type = KEigenvalue
  []
  [power]
    type = ElementIntegralVariablePostprocessor
    variable = kappa_fission
    block = '1'
  []
[]

[UserObjects]
  [translate_top]
    type = OpenMCCellTransform
    transform_type = 'translation'
    vector_value = '0 shift_top_row 0'
    cell_ids = '2013 2014'
  []
  [translate_right]
    type = OpenMCCellTransform
    transform_type = 'translation'
    vector_value = 'shift_right_column 0 0'
    cell_ids = '2012 2014'
  []
[]

[Executioner]
  type = Transient
  num_steps = 2
[]

[Outputs]
  exodus = true
[]

(test/tests/userobjects/openmc_cell_transform/scaled.i)

[Mesh]
  [pin]
    type = ConcentricCircleMeshGenerator
    num_sectors = 6
    radii = '1.0'
    rings = '3 3'
    has_outer_square = on
    pitch = 4.0
    preserve_volumes = yes
    smoothing_max_it = 3
  []
  [assembly]
    type = CartesianIDPatternedMeshGenerator
    inputs = 'pin'
    pattern = '0 0;
               0 0'
    assign_type = 'cell'
    id_name = 'pin_id'
  []
  [delete]
    # Only keeping block 1 (fuel pins) for this test
    type = BlockDeletionGenerator
    input = assembly
    block = 2
  []
  [extrude]
    type = AdvancedExtruderGenerator
    input = delete
    direction = '0 0 1'
    heights = '30'
    num_layers = 1
  []
  [translate]
    type = TransformGenerator
    input = extrude
    transform = TRANSLATE_CENTER_ORIGIN
    vector_value = '-12 12 0'
  []
  [scale_to_m]
    type = TransformGenerator
    input = translate
    transform = SCALE
    vector_value = '0.01 0.01 0.01'
  []
[]


[GlobalParams]
  displacements = 'disp_x disp_y disp_z'
  use_displaced_mesh = true
[]

[Problem]
  type = OpenMCCellAverageProblem
  cell_level = 2
  verbose = true
  power = 100
  scaling = 100.0

  [Tallies]
    [heat]
      type = CellTally
      score = 'kappa_fission'
      block = '1'
    []
  []
[]

[AuxVariables]
  [disp_x]
    [AuxKernel]
        type = FunctionAux
        variable = disp_x
        function = disp_x_fn
        execute_on = 'timestep_begin'
    []
  []
  [disp_y]
    [AuxKernel]
        type = FunctionAux
        variable = disp_y
        function = disp_y_fn
        execute_on = 'timestep_begin'
    []
  []
  [disp_z]
  []
[]

[Functions]
  [disp_x_fn]
    type = ParsedFunction
    expression = '1e-2*2*t'
  []
  [disp_y_fn]
    type = ParsedFunction
    expression = '1e-2*2*t'
  []
[]

[Postprocessors]
  [shift_x]
    type = FunctionValuePostprocessor
    function = disp_x_fn
    execute_on = 'timestep_begin'
  []
  [shift_y]
    type = FunctionValuePostprocessor
    function = disp_y_fn
    execute_on = 'timestep_begin'
  []
  [k]
    type = KEigenvalue
  []
  [power]
    type = ElementIntegralVariablePostprocessor
    variable = kappa_fission
    block = '1'
  []
[]

[UserObjects]
  [translate_cells]
    type = OpenMCCellTransform
    transform_type = 'translation'
    vector_value = 'shift_x shift_y 0'
    cell_ids = '2011'
    execute_on = 'timestep_begin'
  []
[]

[Executioner]
  type = Transient
  num_steps = 2
[]

[Outputs]
  exodus = true
[]

(test/tests/userobjects/openmc_cell_transform/cells_shadow.i)

[Mesh]
  [block]
    type = GeneratedMeshGenerator
    dim = 3
    nx = 20
    ny = 20
    nz = 1
    xmin = -12
    xmax =  12
    ymin = -12
    ymax =   4
    zmin =   0
    zmax =  30
  []
[]

[Problem]
  type = OpenMCCellAverageProblem
  verbose = true
  power = 100.0
  cell_level = 1
  reset_seed = true
  xml_directory=./cells_shadow

  [Tallies]
    [heat]
      type = CellTally
      score = 'kappa_fission'
    []
  []
[]

[Functions]
  [shift_y_fn]
    type = ParsedFunction
    expression = '-t'
  []
[]

[Postprocessors]
  [shift_y]
    type = FunctionValuePostprocessor
    function = shift_y_fn
    execute_on = 'timestep_begin'
  []
  [k]
    type = KEigenvalue
  []
  [power]
    type = ElementIntegralVariablePostprocessor
    variable = kappa_fission
  []
[]

[UserObjects]
  [move_bundle]
    type = OpenMCCellTransform
    transform_type = 'translation'
    vector_value = '0 shift_y 0'
    cell_ids = '2011'
    execute_on = 'timestep_begin'
  []
[]

[Executioner]
  type = Transient
  num_steps = 4
[]

[Outputs]
  exodus = true
[]

(test/tests/userobjects/openmc_cell_transform/translate_cells.i)

[Mesh]
  [pin]
    type = ConcentricCircleMeshGenerator
    num_sectors = 6
    radii = '1.0'
    rings = '3 3'
    has_outer_square = on
    pitch = 4.0
    preserve_volumes = yes
    smoothing_max_it = 3
  []
  [assembly]
    type = CartesianIDPatternedMeshGenerator
    inputs = 'pin'
    pattern = '0 0;
               0 0'
    assign_type = 'cell'
    id_name = 'pin_id'
  []
  [delete]
    # Only keeping block 1 (fuel pins) for this test
    type = BlockDeletionGenerator
    input = assembly
    block = 2
  []
  [extrude]
    type = AdvancedExtruderGenerator
    input = delete
    direction = '0 0 1'
    heights = '30'
    num_layers = 1
  []
  [translate]
    type = TransformGenerator
    input = extrude
    transform = TRANSLATE_CENTER_ORIGIN
    vector_value = '-12 12 0'
  []
[]


[GlobalParams]
  displacements = 'disp_x disp_y disp_z'
  use_displaced_mesh = true
[]

[Problem]
  type = OpenMCCellAverageProblem
  cell_level = 2
  verbose = true
  power = 100

  [Tallies]
    [heat]
      type = CellTally
      score = 'kappa_fission'
      block = '1'
    []
  []
[]

[AuxVariables]
  [disp_x]
    [AuxKernel]
        type = FunctionAux
        variable = disp_x
        function = disp_x_fn
        execute_on = 'timestep_begin'
    []
  []
  [disp_y]
    [AuxKernel]
        type = FunctionAux
        variable = disp_y
        function = disp_y_fn
        execute_on = 'timestep_begin'
    []
  []
  [disp_z]
  []
[]

[Functions]
  [disp_x_fn]
    type = ParsedFunction
    expression = '2*t'
  []
  [disp_y_fn]
    type = ParsedFunction
    expression = '2*t'
  []
[]

[Postprocessors]
  [shift_x]
    type = FunctionValuePostprocessor
    function = disp_x_fn
    execute_on = 'timestep_begin'
  []
  [shift_y]
    type = FunctionValuePostprocessor
    function = disp_y_fn
    execute_on = 'timestep_begin'
  []
  [k]
    type = KEigenvalue
  []
  [power]
    type = ElementIntegralVariablePostprocessor
    variable = kappa_fission
    block = '1'
  []
[]

[UserObjects]
  [translate_cells]
    type = OpenMCCellTransform
    transform_type = 'translation'
    vector_value = 'shift_x shift_y 0'
    cell_ids = '2011'
    execute_on = 'timestep_begin'
  []
[]

[Executioner]
  type = Transient
  num_steps = 2
[]

[Outputs]
  exodus = true
[]

(test/tests/userobjects/openmc_cell_transform/rotate_cells.i)

[Mesh]
  [pin]
    type = ConcentricCircleMeshGenerator
    num_sectors = 6
    radii = '1.0'
    rings = '3 3'
    has_outer_square = on
    pitch = 4.0
    preserve_volumes = yes
    smoothing_max_it = 3
  []
  [assembly]
    type = CartesianIDPatternedMeshGenerator
    inputs = 'pin'
    pattern = '0 0;
               0 0'
    assign_type = 'cell'
    id_name = 'pin_id'
  []
  [delete]
    # Only keeping block 1 (fuel pins) for this test
    type = BlockDeletionGenerator
    input = assembly
    block = 2
  []
  [extrude]
    type = AdvancedExtruderGenerator
    input = delete
    direction = '0 0 1'
    heights = '30'
    num_layers = 1
  []
  [translate]
    type = TransformGenerator
    input = extrude
    transform = TRANSLATE_CENTER_ORIGIN
    vector_value = '-12 12 0'
  []
[]


[GlobalParams]
  displacements = 'disp_x disp_y disp_z'
  use_displaced_mesh = true
[]

[Problem]
  type = OpenMCCellAverageProblem
  cell_level = 2
  verbose = true
  power = 100

  [Tallies]
    [heat]
      type = CellTally
      score = 'kappa_fission'
      block = '1'
    []
  []
[]

[AuxVariables]
  [disp_x]
    [AuxKernel]
        type = FunctionAux
        variable = disp_x
        function = disp_x_fn
        execute_on = 'timestep_begin'
        use_displaced_mesh = false
    []
  []
  [disp_y]
    [AuxKernel]
        type = FunctionAux
        variable = disp_y
        function = disp_y_fn
        execute_on = 'timestep_begin'
        use_displaced_mesh = false
    []
  []
  [disp_z]
  []
[]

[Functions]
  [psi_fn]
    type = ParsedFunction
    expression = '5*t'
  []
  [disp_x_fn]
    type = ParsedFunction
    expression = (cos(5*t*3.14159265359/180)-1)*x-sin(5*t*3.14159265359/180)*y
  []
  [disp_y_fn]
    type = ParsedFunction
    expression = sin(5*t*3.14159265359/180)*x+(cos(5*t*3.14159265359/180)-1)*y
  []
[]

[Postprocessors]
  [psi]
    type = FunctionValuePostprocessor
    function = psi_fn
    execute_on = 'timestep_begin'
  []
  [k]
    type = KEigenvalue
  []
  [power]
    type = ElementIntegralVariablePostprocessor
    variable = kappa_fission
    block = '1'
  []
[]

[UserObjects]
  [rotate_cells]
    type = OpenMCCellTransform
    transform_type = 'rotation'
    vector_value = '0 0 psi'
    cell_ids = '2011'
    execute_on = 'timestep_begin'
  []
[]

[Executioner]
  type = Transient
  num_steps = 2
[]

[Outputs]
  exodus = true
[]

(test/tests/userobjects/openmc_cell_transform/empty_cell_ids.i)

[Mesh]
  [pin]
    type = ConcentricCircleMeshGenerator
    num_sectors = 6
    radii = '1.0'
    rings = '3 3'
    has_outer_square = on
    pitch = 4.0
    preserve_volumes = yes
    smoothing_max_it = 3
  []
  [assembly]
    type = CartesianIDPatternedMeshGenerator
    inputs = 'pin'
    pattern = '0 0;
               0 0'
    assign_type = 'cell'
    id_name = 'pin_id'
  []
  [delete]
    # Only keeping block 1 (fuel pins) for this test
    type = BlockDeletionGenerator
    input = assembly
    block = 2
  []
  [extrude]
    type = MeshExtruderGenerator
    input = delete
    extrusion_vector = '0 0 30'
  []
  [translate]
    type = TransformGenerator
    input = extrude
    transform = TRANSLATE_CENTER_ORIGIN
    vector_value = '-12 12 0'
  []
[]


[GlobalParams]
  displacements = 'disp_x disp_y disp_z'
  use_displaced_mesh = true
[]

[Problem]
  type = OpenMCCellAverageProblem
  # Updating cell_level to 2 to account for the nested
  # universes. Refer to OpenMCCellAverageProblem docs for more details.
  cell_level = 2
  verbose = true
  power = 100

  [Tallies]
    [heat]
      type = CellTally
      score = 'kappa_fission'
      block = '1'
    []
  []
[]

[AuxVariables]
  [disp_x]
    [AuxKernel]
        type = FunctionAux
        variable = disp_x
        function = disp_x_fn
        execute_on = 'timestep_begin'
    []
  []
  [disp_y]
    [AuxKernel]
        type = FunctionAux
        variable = disp_y
        function = disp_y_fn
        execute_on = 'timestep_begin'
    []
  []
  [disp_z]
  []
[]

[Functions]
  [disp_x_fn]
    type = ParsedFunction
    expression = '2*t'
  []
  [disp_y_fn]
    type = ParsedFunction
    expression = '2*t'
  []
[]

[Postprocessors]
  [shift_x]
    type = FunctionValuePostprocessor
    function = disp_x_fn
    execute_on = 'timestep_begin'
  []
  [shift_y]
    type = FunctionValuePostprocessor
    function = disp_y_fn
    execute_on = 'timestep_begin'
  []
  [k]
    type = KEigenvalue
  []
  [power]
    type = ElementIntegralVariablePostprocessor
    variable = kappa_fission
    block = '1'
  []
[]

[UserObjects]
  [translate_cells]
    type = OpenMCCellTransform
    transform_type = 'translation'
    vector_value = 'shift_x shift_y 0'
    cell_ids = ''
    execute_on = 'timestep_begin'
  []
[]

[Executioner]
  type = Transient
  num_steps = 2
[]

[Outputs]
  exodus = true
[]

Description
Example Input Syntax
Input Parameters
Input Files