UPuZrFastNeutronFlux

Computes fast neutron flux and fluence for UPuZr.

Description

The fast neutron flux, can be estimated by back-calculating the total flux, , from the axial fission rate density, , dividing by the macroscopic cross section estimated from the initial isotopics of the fuel, , and estimating the ratio of fast to total neutron flux, ,

The axial fission rate density can be calculated using the average rod power and axial profile, similar to the treatment in UPuZrFissionRate in cylindrical 2DRz geometry only (i.e. radial direction and axial direction ). is calculated based on the rod linear power and axial power profile as, where (J/fsn) is the energy released per fission event.

is passed as a Function given only as a function of time. This function corresponds to the power produced by the entire fuel pin.

is also passed as a Function, only as a function of time and axial position. This can be completed in any Function, but is typically provided via PowerPeakingFunction. represents the ratio between the power at any axial slice of the fuel and the total rod power , and must be normalized to return an average value of 1 over the entire length of the rod, where is the length of the rod.

The macroscopic cross section can be estimated from the weighted sum of number density of the individual fuel constituents by their microscopic fission cross-sections , where the set of all constituents is taken as {U-235, U-238, Pu-239, Pu-240}. The individual number densities are calculated from the atom weights of the constituents, , the atom fractions of each constituent , and the total fuel density, ,

The microscopic fission cross-sections implemented as defaults in UPuZrFastNeutronFlux are collapsed one-group cross-sections from the eight-group cross sections provided in Waltar et al. (2011), weighted for the EBR-II flux spectrum, as provided by Withop et al. (1969).

The ratio of the fast to total neutron flux, is estimated from Withop et al. (1969), and corresponds to the neutron flux with energies above 0.1 MeV.

Given the flux at each timestep, the fast neutron fluence can be optionally calculated via an average over the current and previous time step,

Similarly, the displacements per atom (dpa) can be calculated assuming a conversion factor of n/m per dpa from Waltar et al. (2011),

Example Input Syntax

[Materials<<<{"href": "../../syntax/Materials/index.html"}>>>]
  [flux]
    type = UPuZrFastNeutronFlux<<<{"description": "Computes fast neutron flux and fluence for UPuZr.", "href": "UPuZrFastNeutronFlux.html"}>>>
    axial_power_profile<<<{"description": "Function that describes the axial power profile as a function of axial position and time."}>>> = power_history
    rod_linear_power<<<{"description": "Function that describes the linear power as a function of time."}>>> = axial_peaking_factors
    initial_X_Pu<<<{"description": "Initial atom fraction of plutonium"}>>> = 0.2
    initial_X_Zr<<<{"description": "Initial atom fraction of zirconium"}>>> = 0.1
    initial_density<<<{"description": "Initial density of the fuel"}>>> = 15800
    pellet_radius<<<{"description": "Fuel pellet radius"}>>> = 0.003
    enrichment_Pu240<<<{"description": "Initial ratio of Pu-240 to total plutonium"}>>> = 0.3
    enrichment_U235<<<{"description": "Initial ratio of U-235 to total uranium"}>>> = 0.2
    outputs<<<{"description": "Vector of output names where you would like to restrict the output of variables(s) associated with this object"}>>> = all
    calculate_fluence<<<{"description": "Flag to calculate total neutron fluence from the fast flux."}>>> = true
  []
[]
(test/tests/upuzr_fast_neutron_flux/nonad.i)

Input Parameters

  • axial_power_profileFunction that describes the axial power profile as a function of axial position and time.

    C++ Type:FunctionName

    Unit:(no unit assumed)

    Controllable:No

    Description:Function that describes the axial power profile as a function of axial position and time.

  • initial_X_PuInitial atom fraction of plutonium

    C++ Type:double

    Unit:(no unit assumed)

    Controllable:No

    Description:Initial atom fraction of plutonium

  • initial_X_ZrInitial atom fraction of zirconium

    C++ Type:double

    Unit:(no unit assumed)

    Controllable:No

    Description:Initial atom fraction of zirconium

  • initial_densityInitial density of the fuel

    C++ Type:double

    Unit:(no unit assumed)

    Controllable:No

    Description:Initial density of the fuel

  • pellet_radiusFuel pellet radius

    C++ Type:double

    Unit:(no unit assumed)

    Controllable:No

    Description:Fuel pellet radius

  • rod_linear_powerFunction that describes the linear power as a function of time.

    C++ Type:FunctionName

    Unit:(no unit assumed)

    Controllable:No

    Description:Function that describes the linear power as a function of time.

Required Parameters

  • 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

  • calculate_dpaFalseFlag to calculate dpa.

    Default:False

    C++ Type:bool

    Controllable:No

    Description:Flag to calculate dpa.

  • calculate_dpa_rateFalseFlag to calculate dpa rate.

    Default:False

    C++ Type:bool

    Controllable:No

    Description:Flag to calculate dpa rate.

  • calculate_fluenceFalseFlag to calculate total neutron fluence from the fast flux.

    Default:False

    C++ Type:bool

    Controllable:No

    Description:Flag to calculate total neutron fluence from the fast flux.

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

    Default:True

    C++ Type:bool

    Controllable:No

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

  • 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 computeQpProperties() 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

    Options:NONE, ELEMENT, SUBDOMAIN

    Controllable:No

    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 computeQpProperties() for the 0th quadrature point, and then copy that value to the other qps. Evaluations on element qps will be skipped

  • declare_suffixAn optional suffix parameter that can be appended to any declared 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 declared properties. The suffix will be prepended with a '_' character.

  • dpa_conversion_factor2e+25Conversion factor from fast neutron fluence to dpa, in [n/m^2 per dpa].

    Default:2e+25

    C++ Type:double

    Unit:(no unit assumed)

    Controllable:No

    Description:Conversion factor from fast neutron fluence to dpa, in [n/m^2 per dpa].

  • dpa_namedpaName of the dpa material property this object creates

    Default:dpa

    C++ Type:MaterialPropertyName

    Unit:(no unit assumed)

    Controllable:No

    Description:Name of the dpa material property this object creates

  • energy_per_fission3.28451e-11energy per fission

    Default:3.28451e-11

    C++ Type:double

    Unit:(no unit assumed)

    Controllable:No

    Description:energy per fission

  • enrichment_Pu2400.1Initial ratio of Pu-240 to total plutonium

    Default:0.1

    C++ Type:double

    Unit:(no unit assumed)

    Controllable:No

    Description:Initial ratio of Pu-240 to total plutonium

  • enrichment_U2350.67Initial ratio of U-235 to total uranium

    Default:0.67

    C++ Type:double

    Unit:(no unit assumed)

    Controllable:No

    Description:Initial ratio of U-235 to total uranium

  • fast_neutron_fluence_namefast_neutron_fluenceName of the fast neutrom flux material property this object creates

    Default:fast_neutron_fluence

    C++ Type:MaterialPropertyName

    Unit:(no unit assumed)

    Controllable:No

    Description:Name of the fast neutrom flux material property this object creates

  • fast_neutron_flux_namefast_neutron_fluxName of the fast neutrom flux material property this object creates

    Default:fast_neutron_flux

    C++ Type:MaterialPropertyName

    Unit:(no unit assumed)

    Controllable:No

    Description:Name of the fast neutrom flux material property this object creates

  • fast_spectrum_ratio0.9Ratio of fast flux (greater than 0.1 MeV) to total flux.

    Default:0.9

    C++ Type:double

    Unit:(no unit assumed)

    Controllable:No

    Description:Ratio of fast flux (greater than 0.1 MeV) to total flux.

  • pellet_inner_radius0Pellet inner radius

    Default:0

    C++ Type:double

    Unit:(no unit assumed)

    Controllable:No

    Description:Pellet inner radius

  • sigma_Pu2391.658Collapsed one-group fission cross-section for plutonium-239 [b]

    Default:1.658

    C++ Type:double

    Unit:(no unit assumed)

    Controllable:No

    Description:Collapsed one-group fission cross-section for plutonium-239 [b]

  • sigma_Pu2400.703Collapsed one-group fission cross-section for plutonium-240 [b]

    Default:0.703

    C++ Type:double

    Unit:(no unit assumed)

    Controllable:No

    Description:Collapsed one-group fission cross-section for plutonium-240 [b]

  • sigma_U2351.327Collapsed one-group fission cross-section for uranium-235 [b]

    Default:1.327

    C++ Type:double

    Unit:(no unit assumed)

    Controllable:No

    Description:Collapsed one-group fission cross-section for uranium-235 [b]

  • sigma_U2380.095Collapsed one-group fission cross-section for uranium-238 [b]

    Default:0.095

    C++ Type:double

    Unit:(no unit assumed)

    Controllable:No

    Description:Collapsed one-group fission cross-section for uranium-238 [b]

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.

  • 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

  • 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

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

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

    Controllable:No

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

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

    Default:none

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

    Controllable:No

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

Outputs 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

References

  1. A.E. Waltar, D.R. Todd, and P.V. Tsvetkov. Fast Spectrum Reactors. Springer US, 2011. ISBN 9781441995728. URL: https://books.google.com/books?id=z8z\_RNUZSbEC.[BibTeX]
  2. A Withop, B A Hutchins, and G C Martin. Analytical Procedures and Applications of Fluence Determinations from EBR-II Flux Wires. Technical Report, General Electric Company, January 1969.[BibTeX]