PyCCEGAIrradiationEigenstrain

Computes irradiation-induced dimensional changes (IIDC) for PyC.

Description

The irradiation-induced dimensional change (IIDC) of the buffer is given by Miller et al. (2018) and Ho (1993). The strains, (%) for radial,tangential,isotropic are given by where (10 n/m, 0.18 MeV) is the fast neutron fluence, and through are BaconAnisotropyFactor- and temperature-dependent polynomial coefficients ( g/cm) at varied temperatures. These are tabulated below.

Table 1: Polynomial coefficients for isotropic strain components.

T()BAF
6001.0000-1.240800.001750.08533-0.01253
10321.0000-1.523900.130480.06299-0.01072
13501.0000-1.42840-0.195630.18991-0.02591

Table 2: Polynomial coefficients for radial strain components.

BAF=1.00001.02121.04881.07691.17461.2787
600-1.24080-1.10640-0.94333-0.78045-0.157140.40265
0.00175-0.03128-0.03589-0.02975-0.14889-0.16501
0.085330.091840.081840.066550.075460.03676
-0.01253-0.01220-0.00958-0.00626-0.002930.00706
1032-1.52390-2.07520-2.00470-1.81690-1.18540-0.45900
0.130481.378451.303801.108500.649950.51172
0.06299-0.48993-0.37280-0.238680.01380-0.03245
-0.010720.066020.045380.02484-0.01284-0.00142
1350-1.42840-1.54330-1.49640-0.895221.209303.71620
-0.195630.598041.166210.80331-0.53861-2.70420
0.18991-0.09997-0.30106-0.090090.431141.17990
-0.025910.009780.034750.00467-0.05590-0.13910

Table 3: Polynomial coefficients for tangential strain components.

BAF=1.00001.03031.07691.12501.22581.3333
600-1.24080-1.38550-1.46790-1.64660-1.84990-2.19190
0.001750.05307-0.028360.03928-0.093580.02675
0.085330.076200.121390.100670.181190.15352
-0.01253-0.01245-0.01948-0.01764-0.03036-0.02972
1032-1.52390-1.57590-1.32200-1.18700-0.96963-0.81239
0.130480.09019-0.51928-0.90635-1.59110-2.20760
0.062990.053060.276030.410460.646890.88496
-0.01072-0.00815-0.03465-0.05067-0.07682-0.10457
1350-1.42840-2.24680-2.82930-3.25550-4.44780-5.67140
-0.195630.482430.760880.904231.603202.41920
0.18991-0.07687-0.22314-0.33175-0.58683-0.86155
-0.025910.004640.024310.043290.074580.10668

The polynomial coefficients at other BAF and temperatures are interpolated or extrapolated from these same tables. The isotropic strain (BAF = 1.0) is calculated at the temperature of the PyC and adjusted for density by applying an isotropic scaling factor, . The isotropic scaling factor—the ratio of the isotropic strain at a given density to the isotropic strain at —is computed as:

The isotropic scaling factor is calculated using the values in Table 4, which shows the relationship between the isotropic strain and density at an irradiation temperature and a fast fluence. Adjustments for density at other BAF values are made by applying an anisotropic scaling factor, . The anisotropic scaling factor—the ratio of the difference between the radial and tangential strain components at a given density to the difference between the radial and tangential strain components at —is computed as:

The anisotropic scaling factor is calculated using the values in Table 4, which shows the relationship between the difference between the radial and tangential strain components and density at an irradiation temperature and a fast fluence. Thus, the adjusted radial and tangential strains become

Table 4: Isotropic strain at irradiation temperature of 1100C and fast fluence of 3.7x10 n/m (0.18 MeV).

(g/cm) (%) - (%)
1.00-16.150.000
1.20-13.110.500
1.40-9.981.100
1.50-8.931.650
1.60-6.972.450
1.80-4.426.305
1.90-3.417.900
1.96-2.759.600
2.00-2.3311.100

Note that the strains are then rotated based on the coordinates supplied by the user (see Ho (1993) and Miller et al. (2018)). The correlation uses fast fluence with neutron energy threshold 0.18 MeV. The model performs the fast fluence conversion from 0.10 MeV to 0.18 MeV using flux conversion factor.

Figure 1 and Figure 2 shows dimensional change of pyrocarbon as a function of fluence at various temperatures for BAF=1.036 and 1.063, respectively.

Figure 1: Dimensional change of pyrocarbon as a function of fluence at various temperatures, , BAF = 1.036

Figure 2: Dimensional change of pyrocarbon as a function of fluence at various temperatures, , BAF = 1.063

Validity Range

For temperatures outside of 600-1350^{\circ}C, coefficients are extrapolated.

BAF does not use extrapolation. For values exceed the maximum, the strain rates are set to the values calculated at the maximum BAF values.

Example Input Syntax

[Materials<<<{"href": "../../../syntax/Materials/index.html"}>>>]
  [irradiation_strain]
    type = PyCCEGAIrradiationEigenstrain<<<{"description": "Computes irradiation-induced dimensional changes (IIDC) for PyC.", "href": "PyCCEGAIrradiationEigenstrain.html"}>>>
    eigenstrain_name<<<{"description": "Material property name for the eigenstrain tensor computed by this model. IMPORTANT: The name of this property must also be provided to the strain calculator."}>>> = IIDC_strain
    temperature<<<{"description": "Coupled temperature"}>>> = temperature
  []
[]
(test/tests/triso/pyc_eigenstrains/irradiation_strain/test_cega.i)

Input Parameters

  • eigenstrain_nameMaterial property name for the eigenstrain tensor computed by this model. IMPORTANT: The name of this property must also be provided to the strain calculator.

    C++ Type:std::string

    Controllable:No

    Description:Material property name for the eigenstrain tensor computed by this model. IMPORTANT: The name of this property must also be provided to the strain calculator.

  • flux_conversion_factorConvert fast neutron flux E>0.10 to E>0.18 MeV

    C++ Type:double

    Unit:(no unit assumed)

    Controllable:No

    Description:Convert fast neutron flux E>0.10 to E>0.18 MeV

  • temperatureCoupled temperature

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

    Unit:(no unit assumed)

    Controllable:No

    Description:Coupled temperature

Required Parameters

  • base_nameOptional parameter that allows the user to define multiple mechanics material systems on the same block, i.e. for multiple phases

    C++ Type:std::string

    Controllable:No

    Description:Optional parameter that allows the user to define multiple mechanics material systems on the same block, i.e. for multiple phases

  • 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

  • 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.

  • disp_ppX0The reporting postprocessor for particle displacement x-axis

    Default:0

    C++ Type:PostprocessorName

    Unit:(no unit assumed)

    Controllable:No

    Description:The reporting postprocessor for particle displacement x-axis

  • disp_ppY0The reporting postprocessor for particle displacement y-axis

    Default:0

    C++ Type:PostprocessorName

    Unit:(no unit assumed)

    Controllable:No

    Description:The reporting postprocessor for particle displacement y-axis

  • disp_ppZ0The reporting postprocessor for particle displacement z-axis

    Default:0

    C++ Type:PostprocessorName

    Unit:(no unit assumed)

    Controllable:No

    Description:The reporting postprocessor for particle displacement z-axis

  • fast_neutron_fluencefast_neutron_fluenceCoupled fast (E>0.10 MeV) neutron fluence (n/m^2)

    Default:fast_neutron_fluence

    C++ Type:MaterialPropertyName

    Unit:(no unit assumed)

    Controllable:No

    Description:Coupled fast (E>0.10 MeV) neutron fluence (n/m^2)

  • particle_center0 0 0Center of particle

    Default:0 0 0

    C++ Type:libMesh::Point

    Controllable:No

    Description:Center of particle

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

  • irradiation_eigenstrain_scale_factor1Scale factor for PyC IIDC

    Default:1

    C++ Type:double

    Unit:(no unit assumed)

    Controllable:No

    Description:Scale factor for PyC IIDC

Advanced: Scaling Factors 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. F. Ho. NP-MHTGR: Material Models of Pyrocarbon and Pyrolytic Silicon Carbide. Report CEGA-002820 Rev. 1, CEGA Corporation, July 1993.[BibTeX]
  2. G.K. Miller, D.A. Petti, J.T. Maki, D.L. Knudson, and W.F. Skerjanc. PARFUME Theory and Model Basis Report. Report INL/EXT-08-14497 (Rev.1), Idaho National Laboratory, September 2018.[BibTeX]