SCMTriPowerAux

Computes axial power rate (W/m) assigned to the fuel pins in a triangular lattice arrangement

Overview

This AuxKernel does the same thing as the SCMTriPowerIC IC kernel, but is more versatile in the sense that it can populate q_prime not only during initialization but at multiple times during the solve. This object does two things:

At initial setup and at the start of each time step, it computes the trapezoidal integral of the axial power profile function over each pin on the subchannel axial grid. This normalization does not depend on "power".
Every time it is executed, as set by "execute_on", it sets q_prime at each pin node to the pin power times the axial power profile function, divided by that integral. The pin power is computed from the current value of "power" and the radial power distribution.

The "power" postprocessor executes before this object on every execution flag they share, so q_prime uses its current value, including within fixed point iterations. The exception is a "power" postprocessor listed in the executioner's transformed_postprocessors: it is relaxed or accelerated after the TIMESTEP_BEGIN objects execute, so q_prime set on TIMESTEP_BEGIN uses the value before that transformation. Execute both on the same flags, for example TIMESTEP_BEGIN so that the solver uses the power of the current time step; otherwise a time-dependent power is applied one execution late. This object warns if the postprocessor does not execute on all of its "execute_on" flags, or if it sets force_postaux. These checks are skipped when "power" is a Receiver postprocessor, because its value is set by a transfer rather than by its own execution. In that case q_prime is current only if the application sending the power computes it before the transfer executes, for example on MULTIAPP_FIXED_POINT_BEGIN when the transfer executes on TIMESTEP_BEGIN; otherwise q_prime uses the power of the previous time step. Set "verbose" to print the per-pin correction factor, the heated length divided by the integral of the axial power profile function, every time it is computed.

The axial power profile function "axial_heat_rate" may depend on time: both the integral and q_prime are evaluated at the current time, so its amplitude and its shape can change between time steps while each pin keeps its assigned power. It must not depend on values that change during a time step, such as postprocessors, because the integral is computed at the start of the time step, before they execute, while q_prime uses their updated values. The pin powers then no longer match "power".

Caveat

This AuxKernel requires a pin mesh. The axial heat rate q_prime is assigned only to the nodes of the pin mesh. If the subchannel mesh has no pin mesh, this object reports an error.

Input Parameters

filenamename of radial power profile .txt file (should be a single column) [UnitLess].
C++ Type:std::string
Controllable:No
Description:name of radial power profile .txt file (should be a single column) [UnitLess].
powerThe postprocessor or Real to use for the total power of the subassembly [W]
C++ Type:PostprocessorName
Unit:(no unit assumed)
Controllable:No
Description:The postprocessor or Real to use for the total power of the subassembly [W]
variableThe name of the variable that this object applies to
C++ Type:AuxVariableName
Unit:(no unit assumed)
Controllable:No
Description:The name of the variable that this object applies to

Required Parameters

axial_heat_rate1.0Axial shape of the heat rate as a function of the distance from the start of the heated section [Unitless]. Its magnitude does not matter because each pin is rescaled to its assigned power
Default:1.0
C++ Type:FunctionName
Unit:(no unit assumed)
Controllable:No
Description:Axial shape of the heat rate as a function of the distance from the start of the heated section [Unitless]. Its magnitude does not matter because each pin is rescaled to its assigned power
blockThe list of blocks (ids or names) that this object will be applied
C++ Type:std::vector<SubdomainName>
Controllable:No
Description:The list of blocks (ids or names) that this object will be applied
boundaryThe list of boundaries (ids or names) from the mesh where this object applies
C++ Type:std::vector<BoundaryName>
Controllable:No
Description:The list of boundaries (ids or names) from the mesh where this object applies
check_boundary_restrictedTrueWhether to check for multiple element sides on the boundary in the case of a boundary restricted, element aux variable. Setting this to false will allow contribution to a single element's elemental value(s) from multiple boundary sides on the same element (example: when the restricted boundary exists on two or more sides of an element, such as at a corner of a mesh
Default:True
C++ Type:bool
Controllable:No
Description:Whether to check for multiple element sides on the boundary in the case of a boundary restricted, element aux variable. Setting this to false will allow contribution to a single element's elemental value(s) from multiple boundary sides on the same element (example: when the restricted boundary exists on two or more sides of an element, such as at a corner of a mesh
execute_onLINEAR TIMESTEP_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:LINEAR TIMESTEP_END
C++ Type:ExecFlagEnum
Options:XFEM_MARK, FORWARD, ADJOINT, HOMOGENEOUS_FORWARD, ADJOINT_TIMESTEP_BEGIN, ADJOINT_TIMESTEP_END, 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, MULTISYSTEM_FIXED_POINT_ITERATION_END, FINAL, CUSTOM, PRE_DISPLACE
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.
verboseFalsePrint the per-pin power correction every time it is computed
Default:False
C++ Type:bool
Controllable:No
Description:Print the per-pin power correction every time it is computed

Optional 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.
search_methodnearest_node_connected_sidesChoice of search algorithm. All options begin by finding the nearest node in the primary boundary to a query point in the secondary boundary. In the default nearest_node_connected_sides algorithm, primary boundary elements are searched iff that nearest node is one of their nodes. This is fast to determine via a pregenerated node-to-elem map and is robust on conforming meshes. In the optional all_proximate_sides algorithm, primary boundary elements are searched iff they touch that nearest node, even if they are not topologically connected to it. This is more CPU-intensive but is necessary for robustness on any boundary surfaces which has disconnections (such as Flex IGA meshes) or non-conformity (such as hanging nodes in adaptively h-refined meshes).
Default:nearest_node_connected_sides
C++ Type:MooseEnum
Options:nearest_node_connected_sides, all_proximate_sides
Controllable:No
Description:Choice of search algorithm. All options begin by finding the nearest node in the primary boundary to a query point in the secondary boundary. In the default nearest_node_connected_sides algorithm, primary boundary elements are searched iff that nearest node is one of their nodes. This is fast to determine via a pregenerated node-to-elem map and is robust on conforming meshes. In the optional all_proximate_sides algorithm, primary boundary elements are searched iff they touch that nearest node, even if they are not topologically connected to it. This is more CPU-intensive but is necessary for robustness on any boundary surfaces which has disconnections (such as Flex IGA meshes) or non-conformity (such as hanging nodes in adaptively h-refined meshes).
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

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

(modules/subchannel/test/tests/SCMTriPower/test_with_pins.i)
(modules/subchannel/validation/Blockage/THORS/FFM-5B_low.i)
(modules/subchannel/test/tests/SCMTriPower/seven_pin_shapes.i)

(modules/subchannel/test/tests/SCMTriPower/test_with_pins.i)

T_in = 588.5
flow_area = 0.0004980799633447909 #m2
mass_flux_in = '${fparse 55*3.78541/10/60/flow_area}'
P_out = 2.0e5 # Pa
length = 0.5
num_cells = 40
[TriSubChannelMesh]
  [subchannel]
    type = SCMTriAssemblyMeshGenerator
    nrings = 3
    n_cells = ${num_cells}
    flat_to_flat = 3.41e-2
    heated_length = 0.5
    unheated_length_entry = 0.4
    unheated_length_exit = 0.1
    pin_diameter = 5.84e-3
    pitch = 7.26e-3
    dwire = 1.42e-3
    hwire = 0.3048
  []
[]

[AuxVariables]
  [q_prime_aux]
    block = fuel_pins
  []
[]

[Functions]
  [axial_heat_rate]
    type = ParsedFunction
    expression = '(pi/2)*sin(pi*z/L)'
    symbol_names = 'L'
    symbol_values = '${length}'
  []
[]

[FluidProperties]
  [sodium]
    type = PBSodiumFluidProperties
  []
[]

[SubChannel]
  type = TriSubChannel1PhaseProblem
  fp = sodium
  n_blocks = 1
  P_out = 2.0e5
  compute_density = true
  compute_viscosity = true
  compute_power = true
  implicit = true
  segregated = false
  P_tol = 1.0e-4
  T_tol = 1.0e-5
  verbose_subchannel = true
  interpolation_scheme = upwind
  pin_HTC_closure = 'gnielinski'
  friction_closure = 'Chen'
  full_output = true
  mixing_closure = 'Chen_Todreas'
[]

[SCMClosures]
  [Chen]
    type = SCMFrictionChenTodreas
  []
  [gnielinski]
    type = SCMHTCGnielinski
  []
  [Chen_Todreas]
    type = SCMMixingChenTodreas
    CT = 2.6
  []
[]

[ICs]
  [q_prime_ic]
    type = SCMTriPowerIC
    variable = q_prime
    power = 20000 # W
    filename = "pin_power_profile.txt"
    axial_heat_rate = axial_heat_rate
  []

  [T_ic]
    type = ConstantIC
    variable = T
    value = ${T_in}
  []

  [P_ic]
    type = ConstantIC
    variable = P
    value = 0.0
  []

  [DP_ic]
    type = ConstantIC
    variable = DP
    value = 0.0
  []

  [Viscosity_ic]
    type = ViscosityIC
    variable = mu
    p = ${P_out}
    T = T
    fp = sodium
  []

  [rho_ic]
    type = RhoFromPressureTemperatureIC
    variable = rho
    p = ${P_out}
    T = T
    fp = sodium
  []

  [h_ic]
    type = SpecificEnthalpyFromPressureTemperatureIC
    variable = h
    p = ${P_out}
    T = T
    fp = sodium
  []

  [mdot_ic]
    type = ConstantIC
    variable = mdot
    value = 0.0
  []
[]

[AuxKernels]
  [T_in_bc]
    type = ConstantAux
    variable = T
    boundary = inlet
    value = ${T_in}
    execute_on = 'timestep_begin'
  []
  [mdot_in_bc]
    type = SCMMassFlowRateAux
    variable = mdot
    boundary = inlet
    area = S
    mass_flux = ${mass_flux_in}
    execute_on = 'timestep_begin'
  []
  [q_prime_AUX]
    type = SCMTriPowerAux
    variable = q_prime_aux
    power = 20000 # W
    filename = "pin_power_profile.txt" #type in name of file that describes radial power profile
    axial_heat_rate = axial_heat_rate
    execute_on = 'initial'
  []
[]

[Executioner]
  type = Steady
[]

[Postprocessors]
  [Total_power_IC_defaultPP]
    type = ElementIntegralVariablePostprocessor
    variable = q_prime
    block = fuel_pins
  []
  [Total_power_Aux_defaultPP]
    type = ElementIntegralVariablePostprocessor
    variable = q_prime_aux
    block = fuel_pins
  []
  [Total_power_SCMPinPowerPostprocessor]
    type = SCMPinPowerPostprocessor
  []
  [Total_power_SCMTHPowerPostprocessor]
    type = SCMTHPowerPostprocessor
  []
[]

[VectorPostprocessors]
  [line_check]
    type = LineValueSampler
    variable = 'q_prime q_prime_aux'
    execute_on = 'TIMESTEP_END'
    sort_by = 'z'
    start_point = '0 0 0'
    end_point = '0 0 1.0'
    num_points = ${fparse num_cells + 1}
  []
[]

[Outputs]
  csv = true
[]

(modules/subchannel/validation/Blockage/THORS/FFM-5B_low.i)

################################################################################
## THORS bundle 5B partial edge blockage benchmark                            ##
## SCM simulation, low flow casenn                                            ##
## POC : Vasileios Kyriakopoulos, [email protected]             ##
################################################################################
# Details on the experimental facility modeled can be found at:
# Han, J. T. "Blockages in LMFBR fuel assemblies: A review of experimental and theoretical studies." (1977).
# This input file models a block next to the duct of  the of the assembly
# 102 mm above the start of the heated section.

# Boundary conditions
T_in = 541.55 #K, low flow case
A12 = 1.00423e3
A13 = -0.21390
A14 = -1.1046e-5
rho = '${fparse A12 + A13 * T_in + A14 * T_in * T_in}'
inlet_vel = 0.48 #m/sec, low flow case
mass_flux_in = '${fparse rho *  inlet_vel}'
P_out = 2.0e5 # Pa
[TriSubChannelMesh]
  [subchannel]
    type = SCMTriAssemblyMeshGenerator
    nrings = 3
    n_cells = 50
    flat_to_flat = 0.0324290
    heated_length = 0.4572
    unheated_length_entry = 0.4064
    unheated_length_exit = 0.1524
    pin_diameter = 0.005842
    pitch = 7.2644e-3
    dwire = 0.0014224
    hwire = 0.3048
    z_blockage = '0.49 0.52'
    index_blockage = '29 31 30 32 34 33 35 15 16 8 17 18 9 19'
    reduction_blockage = '0.08 0.08 0.08 0.08 0.08 0.08 0.08 0.08 0.08 0.08 0.08 0.08 0.08 0.08'
    k_blockage = '4 4 4 4 4 4 4 4 4 4 4 4 4 4 '
  []
[]

[FluidProperties]
  [sodium]
    type = PBSodiumFluidProperties
  []
[]

[SubChannel]
  type = TriSubChannel1PhaseProblem
  fp = sodium
  n_blocks = 1
  P_out = 2.0e5
  compute_density = true
  compute_viscosity = true
  compute_power = true
  P_tol = 1.0e-4
  T_tol = 1.0e-4
  implicit = true
  segregated = false
  verbose_subchannel = true
  interpolation_scheme = exponential
  pin_HTC_closure = 'Dittus-Boelter'
  # friction model
  friction_closure = 'Chen'
  full_output = true
  mixing_closure = 'Chen_Todreas'

[]

[SCMClosures]
  [Chen]
    type = SCMFrictionChenTodreas
  []
  [Chen_Todreas]
    type = SCMMixingChenTodreas
    CT = 2.0
  []
  [Dittus-Boelter]
    type = SCMHTCDittusBoelter
  []
[]

[ICs]


  [T_ic]
    type = ConstantIC
    variable = T
    value = ${T_in}
  []

  [P_ic]
    type = ConstantIC
    variable = P
    value = 0.0
  []

  [DP_ic]
    type = ConstantIC
    variable = DP
    value = 0.0
  []

  [Dpin_ic]
    type = ConstantIC
    variable = Dpin
    value = 0.005842
  []

  [Viscosity_ic]
    type = ViscosityIC
    variable = mu
    p = ${P_out}
    T = T
    fp = sodium
  []

  [rho_ic]
    type = RhoFromPressureTemperatureIC
    variable = rho
    p = ${P_out}
    T = T
    fp = sodium
  []

  [h_ic]
    type = SpecificEnthalpyFromPressureTemperatureIC
    variable = h
    p = ${P_out}
    T = T
    fp = sodium
  []

  [mdot_ic]
    type = ConstantIC
    variable = mdot
    value = 0.0
  []
[]

[AuxKernels]
  [T_in_bc]
    type = ConstantAux
    variable = T
    boundary = inlet
    value = ${T_in}
    execute_on = 'timestep_begin'
  []
  [mdot_in_bc]
    type = SCMMassFlowRateAux
    variable = mdot
    boundary = inlet
    area = S
    mass_flux = ${mass_flux_in}
    execute_on = 'timestep_begin'
  []
  [q_prime_Aux]
    type = SCMTriPowerAux
    variable = q_prime
    power = 52800 #W, low flow case
    filename = "pin_power_profile_19.txt"
    execute_on = 'initial timestep_begin'
  []
[]

[Outputs]
  exodus = true
  csv = true
[]

[Postprocessors]
  [1]
    type = SubChannelPointValue
    variable = T
    index = 34
    execute_on = 'initial timestep_end'
    height = 0.94
  []
  [2]
    type = SubChannelPointValue
    variable = T
    index = 33
    execute_on = 'initial timestep_end'
    height = 0.94
  []
  [3]
    type = SubChannelPointValue
    variable = T
    index = 18
    execute_on = 'initial timestep_end'
    height = 0.94
  []
  [4]
    type = SubChannelPointValue
    variable = T
    index = 9
    execute_on = 'initial timestep_end'
    height = 0.94
  []
  [5]
    type = SubChannelPointValue
    variable = T
    index = 3
    execute_on = 'initial timestep_end'
    height = 0.94
  []
  [6]
    type = SubChannelPointValue
    variable = T
    index = 0
    execute_on = 'initial timestep_end'
    height = 0.94
  []
  [7]
    type = SubChannelPointValue
    variable = T
    index = 12
    execute_on = 'initial timestep_end'
    height = 0.94
  []
  [8]
    type = SubChannelPointValue
    variable = T
    index = 25
    execute_on = 'initial timestep_end'
    height = 0.94
  []
[]

[Executioner]
  type = Steady
[]

################################################################################
# A multiapp that projects data to a detailed mesh
################################################################################

[MultiApps]
  [viz]
    type = FullSolveMultiApp
    input_files = "FFM-5B_viz.i"
    execute_on = "timestep_end"
  []
[]

[Transfers]
  [xfer_subchannel]
    type = SCMSolutionTransfer
    to_multi_app = viz
    transfer_type = subchannel
    variable = 'mdot SumWij P DP h T rho mu S displacement w_perim'
  []
  [xfer_q_prime]
    type = SCMSolutionTransfer
    to_multi_app = viz
    transfer_type = pin
    variable = q_prime
  []
[]

(modules/subchannel/test/tests/SCMTriPower/seven_pin_shapes.i)

T_in = 667.15
outlet_pressure = 1.01325e5 # Pa
volume_flow_rate = 0.002090242 # m^3/s
rho_in = '${fparse 1004.23 - 0.21390 * T_in - 1.1046e-5 * T_in * T_in}'
duct_inner_ftf = 0.0769620
pin_diameter = 0.024638
flow_area = '${fparse sqrt(3)/2 * duct_inner_ftf^2 - 7 * pi * pin_diameter^2 / 4}'
mass_flux_in = '${fparse volume_flow_rate * rho_in / flow_area}'
heated_length = 1.0
pin_pitch = 0.027813
# Uniform radial weights, so each of the 7 pins should receive 1/7 of this power
power = 7000.0 # W

# Seven pins: the center pin at the origin and six outer pins one pitch away from it
[TriSubChannelMesh]
  [assembly]
    type = SCMTriAssemblyMeshGenerator
    nrings = 2
    n_cells = 10
    heated_length = ${heated_length}
    flat_to_flat = ${duct_inner_ftf}
    pin_diameter = ${pin_diameter}
    pitch = ${pin_pitch}
    dwire = 0.0
    hwire = 0.0
  []
[]

[Functions]
  # A sine shape on the center pin and a linear shape on the outer pins. Neither is normalized
  # to the heated length. The break at half a pitch from the center lies between the pins.
  [axial_heat_rate]
    type = ParsedFunction
    expression = 'if(sqrt(x*x + y*y) < 0.5*p, sin(pi*z/L), 5*z/L)'
    symbol_names = 'L p'
    symbol_values = '${heated_length} ${pin_pitch}'
  []
[]

[AuxVariables]
  [q_prime_aux]
    block = fuel_pins
  []
  [q_prime_IC_center]
    block = fuel_pins
  []
  [q_prime_IC_outer]
    block = fuel_pins
  []
  [q_prime_aux_center]
    block = fuel_pins
  []
  [q_prime_aux_outer]
    block = fuel_pins
  []
[]

[FluidProperties]
  [sodium]
    type = PBSodiumFluidProperties
  []
[]

[SubChannel]
  type = TriSubChannel1PhaseProblem
  fp = sodium
  n_blocks = 1
  P_out = ${outlet_pressure}
  compute_density = true
  compute_viscosity = true
  compute_power = true
  implicit = true
  segregated = false
  interpolation_scheme = upwind
  friction_closure = uctd_friction
  mixing_closure = kim_chung_mixing
  pin_HTC_closure = kazimi_carelli_htc
  P_tol = 1.0e-8
  T_tol = 1.0e-8
  rtol = 1.0e-10
  atol = 1.0e-10
[]

[SCMClosures]
  [uctd_friction]
    type = SCMFrictionUpgradedChengTodreas
  []
  [kim_chung_mixing]
    type = SCMMixingKimAndChung
  []
  [kazimi_carelli_htc]
    type = SCMHTCKazimiCarelli
  []
[]

[ICs]
  [q_prime_IC]
    type = SCMTriPowerIC
    variable = q_prime
    power = ${power}
    filename = 'seven_pin_power_profile.txt'
    axial_heat_rate = axial_heat_rate
  []
  [T_ic]
    type = ConstantIC
    variable = T
    value = ${T_in}
  []
  [P_ic]
    type = ConstantIC
    variable = P
    value = 0.0
  []
  [mu_ic]
    type = ViscosityIC
    variable = mu
    p = ${outlet_pressure}
    T = T
    fp = sodium
  []
  [rho_ic]
    type = RhoFromPressureTemperatureIC
    variable = rho
    p = ${outlet_pressure}
    T = T
    fp = sodium
  []
  [h_ic]
    type = SpecificEnthalpyFromPressureTemperatureIC
    variable = h
    p = ${outlet_pressure}
    T = T
    fp = sodium
  []
  [mdot_ic]
    type = ConstantIC
    variable = mdot
    value = 0.0
  []
[]

[AuxKernels]
  [q_prime_AUX]
    type = SCMTriPowerAux
    variable = q_prime_aux
    power = ${power}
    filename = 'seven_pin_power_profile.txt'
    axial_heat_rate = axial_heat_rate
    execute_on = 'initial'
  []
  # Split q_prime between the center pin and the outer pins so each power is integrated separately
  [IC_center]
    type = ParsedAux
    variable = q_prime_IC_center
    coupled_variables = 'q_prime'
    expression = 'if(sqrt(x*x + y*y) < 0.5*${pin_pitch}, q_prime, 0)'
    use_xyzt = true
  []
  [IC_outer]
    type = ParsedAux
    variable = q_prime_IC_outer
    coupled_variables = 'q_prime'
    expression = 'if(sqrt(x*x + y*y) > 0.5*${pin_pitch}, q_prime, 0)'
    use_xyzt = true
  []
  [aux_center]
    type = ParsedAux
    variable = q_prime_aux_center
    coupled_variables = 'q_prime_aux'
    expression = 'if(sqrt(x*x + y*y) < 0.5*${pin_pitch}, q_prime_aux, 0)'
    use_xyzt = true
  []
  [aux_outer]
    type = ParsedAux
    variable = q_prime_aux_outer
    coupled_variables = 'q_prime_aux'
    expression = 'if(sqrt(x*x + y*y) > 0.5*${pin_pitch}, q_prime_aux, 0)'
    use_xyzt = true
  []
  [inlet_temperature]
    type = ConstantAux
    variable = T
    boundary = inlet
    value = ${T_in}
    execute_on = 'timestep_begin'
  []
  [inlet_mass_flow]
    type = SCMMassFlowRateAux
    variable = mdot
    boundary = inlet
    area = S
    mass_flux = ${mass_flux_in}
    execute_on = 'timestep_begin'
  []
[]

[Postprocessors]
  [center_pin_power_IC]
    type = ElementIntegralVariablePostprocessor
    variable = q_prime_IC_center
    block = fuel_pins
  []
  [outer_pins_power_IC]
    type = ElementIntegralVariablePostprocessor
    variable = q_prime_IC_outer
    block = fuel_pins
  []
  [center_pin_power_aux]
    type = ElementIntegralVariablePostprocessor
    variable = q_prime_aux_center
    block = fuel_pins
  []
  [outer_pins_power_aux]
    type = ElementIntegralVariablePostprocessor
    variable = q_prime_aux_outer
    block = fuel_pins
  []
  [total_power_TH]
    type = SCMTHPowerPostprocessor
  []
[]

[VectorPostprocessors]
  # Axial q_prime profile of all pins
  [q_prime_profiles]
    type = NodalValueSampler
    variable = 'q_prime q_prime_aux'
    block = fuel_pins
    sort_by = id
  []
[]

[Executioner]
  type = Steady
[]

[Outputs]
  csv = true
[]

Overview
Caveat
Input Parameters
Input Files