# Decay Heat Function

Calculate the decay heat as a fraction of recoverable fission energy using the ANSI/ANS-5.1-2005 Standard.

## Description

DecayHeatFunction computes the value of the decay heat function. The value is zero prior to the specified time_at_shutdown. This postprocessor is typically used for Loss of Coolant Accident simulations.

## Example Input Syntax


[Postprocessors]
[./decay_heat_function]
type = DecayHeatFunction
time_at_shutdown = 1e8
neutron_capture_factor = 1
[../]
[./decay_heat_sum]
type = DecayHeatFunction
time_at_shutdown = 1e8
neutron_capture_factor = 1
table_or_sum = sum
[../]
[]
(test/tests/decay_heating/interpolate_vs_series.i)

## Input 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.

• energy_per_fission3.28451e-11Energy released per fission (J/fission)

Default:3.28451e-11

C++ Type:double

Description:Energy released per fission (J/fission)

• table_or_sumtableInterpolate value from table (fast) or use the 23-term exponential series (slower): table sum

Default:table

C++ Type:MooseEnum

Description:Interpolate value from table (fast) or use the 23-term exponential series (slower): table sum

• neutron_capture_factor1neutron capture factor

Default:1

C++ Type:double

Description:neutron capture factor

• time_at_shutdown1e+10Time at shutdown

Default:1e+10

C++ Type:double

Description:Time at shutdown

### 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.

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

C++ Type:std::vector

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

• 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.

• 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).

• force_preauxFalseForces the GeneralUserObject to be executed in PREAUX

Default:False

C++ Type:bool

Description:Forces the GeneralUserObject to be executed in PREAUX