VacuumConcBC

Overview

This object adds the vacuum boundary condition of the multigroup neutron diffusion equations. The weak form after applying integration by parts to the neutron diffusion term (GroupDiffusion) is:

The value of varies depending on the BC type selected using the vacuum_bc_type parameter. The available options are:

  1. Marshak:

  2. Mark:

  3. Milne:

The Marshak and Mark BCs are derived from vacuum boundary condition approximations using and transport methods, respectively. The Milne BC is derived from the exact analytical solution of the Milne problem (Placzek and Seidel, 1947) and has been proven to be accurate for a wide range of diffusive problems (Rulko et al., 1995).

Example Input File Syntax

Input Parameters

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

    C++ Type:std::vector<BoundaryName>

    Controllable:No

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

  • variableThe name of the variable that this residual object operates on

    C++ Type:NonlinearVariableName

    Controllable:No

    Description:The name of the variable that this residual object operates on

Required Parameters

  • displacementsThe displacements

    C++ Type:std::vector<VariableName>

    Controllable:No

    Description:The displacements

  • 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

    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_exp_formTrueWhether concentrations should be in an expotential/logarithmic format.

    Default:True

    C++ Type:bool

    Controllable:No

    Description:Whether concentrations should be in an expotential/logarithmic format.

  • 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.

  • vacuum_bc_typemarshakWhether to apply Marshak, Mark, or Milne vacuum boundary conditions. Defaults to Marshak.

    Default:marshak

    C++ Type:MooseEnum

    Options:marshak, mark, milne

    Controllable:No

    Description:Whether to apply Marshak, Mark, or Milne vacuum boundary conditions. Defaults to Marshak.

Optional Parameters

  • absolute_value_vector_tagsThe tags for the vectors this residual object should fill with the absolute value of the residual contribution

    C++ Type:std::vector<TagName>

    Controllable:No

    Description:The tags for the vectors this residual object should fill with the absolute value of the residual contribution

  • extra_matrix_tagsThe extra tags for the matrices this Kernel should fill

    C++ Type:std::vector<TagName>

    Controllable:No

    Description:The extra tags for the matrices this Kernel should fill

  • extra_vector_tagsThe extra tags for the vectors this Kernel should fill

    C++ Type:std::vector<TagName>

    Controllable:No

    Description:The extra tags for the vectors this Kernel should fill

  • matrix_tagssystemThe tag for the matrices this Kernel should fill

    Default:system

    C++ Type:MultiMooseEnum

    Options:nontime, system

    Controllable:No

    Description:The tag for the matrices this Kernel should fill

  • vector_tagsnontimeThe tag for the vectors this Kernel should fill

    Default:nontime

    C++ Type:MultiMooseEnum

    Options:nontime, time

    Controllable:No

    Description:The tag for the vectors this Kernel should fill

Tagging 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.

  • diag_save_inThe name of auxiliary variables to save this BC's diagonal jacobian contributions to. Everything about that variable must match everything about this variable (the type, what blocks it's on, etc.)

    C++ Type:std::vector<AuxVariableName>

    Controllable:No

    Description:The name of auxiliary variables to save this BC's diagonal jacobian contributions to. Everything about that variable must match everything about this variable (the type, what blocks it's on, etc.)

  • enableTrueSet the enabled status of the MooseObject.

    Default:True

    C++ Type:bool

    Controllable:Yes

    Description:Set the enabled status of the MooseObject.

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

    Default:True

    C++ Type:bool

    Controllable:No

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

  • save_inThe name of auxiliary variables to save this BC's residual contributions to. Everything about that variable must match everything about this variable (the type, what blocks it's on, etc.)

    C++ Type:std::vector<AuxVariableName>

    Controllable:No

    Description:The name of auxiliary variables to save this BC's residual contributions to. Everything about that variable must match everything about this variable (the type, what blocks it's on, etc.)

  • seed0The seed for the master random number generator

    Default:0

    C++ Type:unsigned int

    Controllable:No

    Description:The seed for the master random number generator

  • 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

Input Files

References

  1. G. Placzek and W. Seidel. Milne's Problem in Transport Theory. Physical Review, 72(7):550–555, October 1947. Publisher: American Physical Society. URL: https://link.aps.org/doi/10.1103/PhysRev.72.550 (visited on 2024-05-31), doi:10.1103/PhysRev.72.550.[BibTeX]
  2. Robert P. Rulko, Djordje Tomašević, and Edward W. Larsen. Variational P1 Approximations of General-Geometry Multigroup Transport Problems. Nuclear Science and Engineering, 121(3):393–404, December 1995. Publisher: Taylor & Francis _eprint: https://doi.org/10.13182/NSE121-393. URL: https://doi.org/10.13182/NSE121-393 (visited on 2024-05-31), doi:10.13182/NSE121-393.[BibTeX]