UO2FissionGasThermal

Computes thermal conductivity and specific heat capacity of uranium dioxide fuel.

Description

UO2FissionGasThermal computes the thermal conductivity of UO $var element = document.getElementById("moose-equation-ad1136b0-2c86-4b44-ae53-325f7c529ff4");katex.render("_2", element, {displayMode:false,throwOnError:false});$ based on Fink (2000) and Lucuta et al. (1996), mesoscale insights, and calculations in UO2Sifgrs. The model builds on UO2Thermal and computes a modified Fink thermal conductivity and a modified correction due to porosity.

The modified Fink equation is $(1)var element = document.getElementById("moose-equation-27a7bfde-87b8-4d5b-92f9-93db5bb9d078");katex.render(" k_{95} = \\left(\\frac{100}{7.5408+17.692 T_n+3.6142 T_n^2 + b_g c_g^{e_g}} + \\left[ \\frac{6400}{T_n^{5/2}} \\right] \\exp{\\left[-\\frac{16.35}{T_n} \\right]} \\right)", element, {displayMode:true,throwOnError:false});$ where $var element = document.getElementById("moose-equation-7a08e945-44f7-4e13-9909-44c07eced347");katex.render("T_n", element, {displayMode:false,throwOnError:false});$ is the temperature in K divided by 1000. The values of $var element = document.getElementById("moose-equation-7269f885-59f3-417a-9f6b-462fba7195f8");katex.render("b_g", element, {displayMode:false,throwOnError:false});$ and $var element = document.getElementById("moose-equation-a8049e64-9414-494a-84a2-12671d792d76");katex.render("e_g", element, {displayMode:false,throwOnError:false});$ depend on whether the analytical dispersed fission gas model or the molecular dynamics fit is used. $var element = document.getElementById("moose-equation-883deaa6-bac6-46d0-b5b8-02bac0099162");katex.render("c_g = \\beta_{sa}g_g\\frac{N_A}{N}", element, {displayMode:false,throwOnError:false});$ . $var element = document.getElementById("moose-equation-499f9e68-a5ff-4a30-874f-0d5c8d9d3fbb");katex.render("\\beta_{sa}", element, {displayMode:false,throwOnError:false});$ is the fraction of intragranular gas existing as single atoms (from Sifgrs), $var element = document.getElementById("moose-equation-b15fb66e-f591-4a63-8b8c-84d318e05c5d");katex.render("g_g", element, {displayMode:false,throwOnError:false});$ is the volume concentration of gas in grains (from Sifgrs), $var element = document.getElementById("moose-equation-7322b265-34cf-404c-bd83-c32964807c8c");katex.render("N_A", element, {displayMode:false,throwOnError:false});$ is Avagadro's number, and $var element = document.getElementById("moose-equation-449052f5-6272-4151-9755-2a2aaedb7d6a");katex.render("N = 12/l_c^3", element, {displayMode:false,throwOnError:false});$ with $var element = document.getElementById("moose-equation-755facc1-8a04-44ff-adc0-308b37572c73");katex.render("l_c", element, {displayMode:false,throwOnError:false});$ being the lattice constant for UO $var element = document.getElementById("moose-equation-188f830f-7edd-41d2-8774-e2302132f77e");katex.render("_2", element, {displayMode:false,throwOnError:false});$ .

Eq. (1) is by the following factor to obtain 100% TD thermal conductivity $(2)var element = document.getElementById("moose-equation-aa53eae6-a2d5-4366-b545-2cf4cdaca481");katex.render(" k = k_{95} \\left(\\frac{1}{1-\\left[ 2.6 - 0.5 T_n \\right] 0.05} \\right)", element, {displayMode:true,throwOnError:false});$

The modified porosity correction is given by $var element = document.getElementById("moose-equation-aa19089d-25a9-4b2d-9a87-f46229a15166");katex.render(" f_{por}' = \\kappa_{GB} \\kappa_{bulk} f_{por}", element, {displayMode:true,throwOnError:false});$ where $var element = document.getElementById("moose-equation-cd1fd866-bf86-4ff5-bfd2-b9e3734d4e46");katex.render("f_{por}'", element, {displayMode:false,throwOnError:false});$ is the modified correction, $var element = document.getElementById("moose-equation-898a0643-dda2-4d12-9318-a48ce397059f");katex.render("\\kappa_{GB}", element, {displayMode:false,throwOnError:false});$ is a correction for grain boundary porosity, $var element = document.getElementById("moose-equation-22d8f16f-d300-417c-bdd1-a93a4ea79aeb");katex.render("\\kappa_{bulk}", element, {displayMode:false,throwOnError:false});$ is a correction for bulk porosity, and $var element = document.getElementById("moose-equation-64ae14cd-9432-4d40-9a9b-cb6594137f93");katex.render("f_{por}", element, {displayMode:false,throwOnError:false});$ is the correction from UO2Thermal.

$var element = document.getElementById("moose-equation-992413d4-b619-47df-967a-3b36683fa85f");katex.render(" \\kappa_{GB} = \\dfrac{1.0}{1 + \\dfrac{k_0 R_k'}{2 r_g}}", element, {displayMode:true,throwOnError:false});$ where $var element = document.getElementById("moose-equation-2fe5c992-a4e2-4ee0-bc8d-3c734070f5ad");katex.render("r_g", element, {displayMode:false,throwOnError:false});$ is the grain radius and $var element = document.getElementById("moose-equation-0a23bc6d-1751-42ea-91f2-866ed130ea90");katex.render("k_0", element, {displayMode:false,throwOnError:false});$ is the unirradiated thermal conductivity of UO $var element = document.getElementById("moose-equation-b0b2b876-58b1-4486-8d1a-520fa1e8e7ea");katex.render("_2", element, {displayMode:false,throwOnError:false});$ . $var element = document.getElementById("moose-equation-f43b02e2-65d0-4751-874e-660e6b56aeef");katex.render(" R_k' = \\frac{R_{num}}{R_{den}} - \\frac{2 r_g}{k_0}", element, {displayMode:true,throwOnError:false});$ with $var element = document.getElementById("moose-equation-d239a2bd-9195-4748-af39-82ad4e542204");katex.render(" R_{num} = R_{0b} R_{cr} R_{0GB} + R_{0b} R_{cr} R_{GB} + R_{0b} R_{0GB} R_b + R_{0b} R_{0GB} R_{GB} + R_{0b} R_b R_{GB} + R_{cr} R_{0GB} R_b + R_{cr} R_b R_{GB} + R_{0GB} R_b R_{GB}", element, {displayMode:true,throwOnError:false});$ and $var element = document.getElementById("moose-equation-44e90dd8-80f8-4696-8c23-b9eecfa550b5");katex.render(" R_{den} = R_{0b} R_{cr} + R_{0b} R_b + R_{0b} R_{gb} + R_{cr} R_{0GB} + R_{cr} R_b + R_{cr} R_{GB} + R_{0GB} R_b + R_{0GB} R_{GB}.", element, {displayMode:true,throwOnError:false});$ $var element = document.getElementById("moose-equation-8a83ea04-60dd-4898-9acf-774e52c9910e");katex.render("R_{0b} = 2 r_g / c_{GB} / k_0", element, {displayMode:false,throwOnError:false});$ , $var element = document.getElementById("moose-equation-4f754d38-ba0f-459d-aa52-8239df929bda");katex.render("R_b = 2 r_b / c_{GB} (1 / k_{bub} - 1 / k_0)", element, {displayMode:false,throwOnError:false});$ , $var element = document.getElementById("moose-equation-a0c4df72-3dd9-487e-a21c-f4a853a6d888");katex.render("R_{0GB} = 2 r_g / (1 - c_{GB}) / k_0", element, {displayMode:false,throwOnError:false});$ , and $var element = document.getElementById("moose-equation-4b50432c-eb54-45c5-87ba-f15266cec065");katex.render("R_{GB} = R_{k0} / (1 - c_{GB})", element, {displayMode:false,throwOnError:false});$ . $var element = document.getElementById("moose-equation-b8ec593c-be8a-4e27-88f0-976021f3c855");katex.render("c_{GB}", element, {displayMode:false,throwOnError:false});$ is the grain boundary coverage. $var element = document.getElementById("moose-equation-cfc0de22-0089-498b-b794-c6ca9ba8e57b");katex.render("R_{cr}", element, {displayMode:false,throwOnError:false});$ is the cross over resistance, and $var element = document.getElementById("moose-equation-68692afe-6d3f-4d78-a47c-4a2ce71c1baa");katex.render("R_{k0}", element, {displayMode:false,throwOnError:false});$ is the grain boundary thermal resistance. $var element = document.getElementById("moose-equation-df6c90f4-e5f5-41e4-8054-90a771ad45ce");katex.render("r_b", element, {displayMode:false,throwOnError:false});$ is the bubble radius, and $var element = document.getElementById("moose-equation-dc0f8357-99b2-4ba7-b53e-ca9f99513c1c");katex.render("k_{bub}", element, {displayMode:false,throwOnError:false});$ is the thermal conductivity in the bubbles.

$var element = document.getElementById("moose-equation-ebbef554-5eb4-4175-9ee0-df72dcbe1847");katex.render(" \\kappa_{bulk} = \\frac{1}{\\dfrac{1}{\\kappa_{me}} + \\dfrac{\\rho_1 \\rho_3}{\\rho_2}}", element, {displayMode:true,throwOnError:false});$ where $var element = document.getElementById("moose-equation-862ae943-23c0-4b88-a07a-7201040697c4");katex.render("\\kappa_{me} = (1 - p_{ig}) / (1 + p_{ig} / 2)", element, {displayMode:false,throwOnError:false});$ and $var element = document.getElementById("moose-equation-d37127ea-a1bd-4ca8-b6a4-2653ed57a0a6");katex.render("p_{ig} = n 4/3 \\pi r_b^3", element, {displayMode:false,throwOnError:false});$ and $var element = document.getElementById("moose-equation-8e0f420a-2d89-4f48-8eba-a46cb99ba590");katex.render("n", element, {displayMode:false,throwOnError:false});$ is the number density of intragranular bubbles. $var element = document.getElementById("moose-equation-31f41c66-63c9-4a4a-8377-394fe7c80ecb");katex.render(" \\rho_1 = 4.5 p_{ig} \\rho_{br}^2", element, {displayMode:true,throwOnError:false});$ $var element = document.getElementById("moose-equation-a125da6b-13ea-4576-a1b1-fe109d3ba8f0");katex.render("\\rho_2 = 1 + \\rho_{br} \\left[ 0.864 + 0.29 \\exp{\\left( -\\frac{1.25}{\\rho_{br}} \\right)} \\right]", element, {displayMode:true,throwOnError:false});$ $var element = document.getElementById("moose-equation-603a82b6-a63c-4042-a8b1-28ede346e3e9");katex.render("\\rho_3 = 1 + 3\\sqrt{\\frac{ p_{ig}}{2}}", element, {displayMode:true,throwOnError:false});$ where $var element = document.getElementById("moose-equation-7c8227a7-2bd0-4451-998d-adfe4aa63ead");katex.render("\\rho_{br}", element, {displayMode:false,throwOnError:false});$ is the phonon mean free path divided by the bubble radius.

Example Input Syntax

[Materials<<<{"href": "../../syntax/Materials/index.html"}>>>]
  [fuel_thermal_meso]
    type = UO2FissionGasThermal<<<{"description": "Computes thermal conductivity and specific heat capacity of uranium dioxide fuel.", "href": "UO2FissionGasThermal.html"}>>>
    block<<<{"description": "The list of blocks (ids or names) that this object will be applied"}>>> = 1
    temperature<<<{"description": "Coupled temperature"}>>> = temp
    burnup<<<{"description": "Coupled burnup"}>>> = burnup
    grain_radius<<<{"description": "Coupled Grain Radius"}>>> = 5e-6
  []
[]

Input Parameters

grain_radiusCoupled Grain Radius
C++ Type:std::vector<VariableName>
Unit:(no unit assumed)
Controllable:No
Description:Coupled Grain Radius
temperatureCoupled temperature
C++ Type:std::vector<VariableName>
Unit:(no unit assumed)
Controllable:No
Description:Coupled temperature
thermal_conductivity_modelFINK_LUCUTAThe thermal conductivity model.
Default:FINK_LUCUTA
C++ Type:MooseEnum
Options:FINK_LUCUTA
Controllable:No
Description:The thermal conductivity model.

Required Parameters

Gd_content0Weight fraction of gadolinium in fuel.
Default:0
C++ Type:double
Unit:(no unit assumed)
Controllable:No
Description:Weight fraction of gadolinium in fuel.
Rcr5e-07Cross over resistance, default value is fit to 3D MARMOT simulation results
Default:5e-07
C++ Type:double
Unit:(no unit assumed)
Controllable:No
Description:Cross over resistance, default value is fit to 3D MARMOT simulation results
Rk01.13e-09GB thermal resistance, defaults to value for Sym. Tilt GB in UO2 from LANL MD.
Default:1.13e-09
C++ Type:double
Unit:(no unit assumed)
Controllable:No
Description:GB thermal resistance, defaults to value for Sym. Tilt GB in UO2 from LANL MD.
axial_relocation_objectName of the AxialRelocationUserObject that determines whether the fuel has crumbled.
C++ Type:UserObjectName
Controllable:No
Description:Name of the AxialRelocationUserObject that determines whether the fuel has crumbled.
base_nameOptional parameter that allows the user to define multiple 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 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
burnupCoupled burnup
C++ Type:std::vector<VariableName>
Unit:(no unit assumed)
Controllable:No
Description:Coupled burnup
burnup_functionBurnup function
C++ Type:FunctionName
Unit:(no unit assumed)
Controllable:No
Description:Burnup function
burnup_materialMaterial property name for burnup.
C++ Type:MaterialPropertyName
Unit:(no unit assumed)
Controllable:No
Description:Material property name for burnup.
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.
dispersed_modelMD_fitWhich parameters are used for the dispersed fission gas model
Default:MD_fit
C++ Type:MooseEnum
Options:analytical, MD_fit
Controllable:No
Description:Which parameters are used for the dispersed fission gas model
dissolved_fpTrueConsider dissolved fission products
Default:True
C++ Type:bool
Controllable:No
Description:Consider dissolved fission products
dissolved_fp_percent0.67Percentage of the dissolved fission product contribution to be used in the model
Default:0.67
C++ Type:double
Unit:(no unit assumed)
Controllable:No
Description:Percentage of the dissolved fission product contribution to be used in the model
gap_thermal_conductivityThe layered average thermal conductivity across the gas gap.
C++ Type:std::vector<VariableName>
Unit:(no unit assumed)
Controllable:No
Description:The layered average thermal conductivity across the gas gap.
gas_typeXeWhich fission gas is used to computer the thermal conductivity of dispersed fission gas
Default:Xe
C++ Type:MooseEnum
Options:Xe, La
Controllable:No
Description:Which fission gas is used to computer the thermal conductivity of dispersed fission gas
hbs_porosity_correctionNONEThe porosity correction method for the thermal conductivity model in the high burnup structure.
Default:NONE
C++ Type:MooseEnum
Options:NONE, KAMPF, LEE, MAXWELLEUCKEN
Controllable:No
Description:The porosity correction method for the thermal conductivity model in the high burnup structure.
initial_porosity0.05Initial porosity. Must be between 0.0 and 1.0.
Default:0.05
C++ Type:double
Unit:(no unit assumed)
Controllable:No
Description:Initial porosity. Must be between 0.0 and 1.0.
k_bub0.00565Thermal conductivity within the bubbles. Defaults to thermal conductivity of Xe.
Default:0.00565
C++ Type:double
Unit:(no unit assumed)
Controllable:No
Description:Thermal conductivity within the bubbles. Defaults to thermal conductivity of Xe.
model_hbs_formationFalseFlag on whether to take into account the volume fraction of high burnup structure that has formed on the thermal conductivity calculation.
Default:False
C++ Type:bool
Controllable:No
Description:Flag on whether to take into account the volume fraction of high burnup structure that has formed on the thermal conductivity calculation.
no_irradFalseUse fink only
Default:False
C++ Type:bool
Controllable:No
Description:Use fink only
only_fission_gasTrueDon't include Lucuta model
Default:True
C++ Type:bool
Controllable:No
Description:Don't include Lucuta model
oxy_to_metal_ratio2Oxygen-to-metal ratio.
Default:2
C++ Type:double
Unit:(no unit assumed)
Controllable:No
Description:Oxygen-to-metal ratio.
porosityCoupled porosity
C++ Type:std::vector<VariableName>
Unit:(no unit assumed)
Controllable:No
Description:Coupled porosity
porosity_materialFalseWhether a material property for porosity is supplied.
Default:False
C++ Type:bool
Controllable:No
Description:Whether a material property for porosity is supplied.

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

specific_heat_scale_factor1Optional scaling factor applied to the overall specific heat.
Default:1
C++ Type:double
Unit:(no unit assumed)
Controllable:No
Description:Optional scaling factor applied to the overall specific heat.
thermal_conductivity_scale_factor1Optional scaling factor applied to the overall thermal conductivity.
Default:1
C++ Type:double
Unit:(no unit assumed)
Controllable:No
Description:Optional scaling factor applied to the overall thermal conductivity.

Advanced: Scaling Factors Parameters

Input Files

(test/tests/meso_thcond_test/sifgrs_swelling_fissiongas_graingrowth.i)
(test/tests/meso_thcond_test/sifgrs_swelling_fissiongas.i)

References

J. K. Fink. Thermophysical properties of uranium dioxide. Journal of Nuclear Materials, 279(1):1–18, 2000.

@ARTICLE{fink00,
    author = "Fink, J. K.",
    title = "Thermophysical properties of uranium dioxide",
    journal = "Journal of Nuclear Materials",
    year = "2000",
    volume = "279",
    pages = "1-18",
    number = "1",
    issn = "0022-3115"
}

P.G. Lucuta, Hj. Matzke, and I.J. Hastings. A pragmatic approach to modelling thermal conductivity of irradiated UO$_2$ fuel: review and recommendations. Journal of Nuclear Materials, 232(2-3):166–180, 1996. URL: http://www.sciencedirect.com/science/article/pii/S0022311596004047, doi:10.1016/S0022-3115(96)00404-7.

@ARTICLE{Lucuta1996,
    author = "Lucuta, P.G. and Matzke, Hj. and Hastings, I.J.",
    title = "A pragmatic approach to modelling thermal conductivity of irradiated {UO}$\_2$ fuel: Review and recommendations",
    journal = "Journal of Nuclear Materials",
    year = "1996",
    volume = "232",
    pages = "166-180",
    number = "2-3",
    bdsk-url-1 = "http://www.sciencedirect.com/science/article/pii/S0022311596004047",
    bdsk-url-2 = "http://dx.doi.org/10.1016/S0022-3115(96)00404-7",
    doi = "10.1016/S0022-3115(96)00404-7",
    issn = "0022-3115",
    url = "http://www.sciencedirect.com/science/article/pii/S0022311596004047"
}

(test/tests/meso_thcond_test/sifgrs_swelling_fissiongas.i)

# This test is for the fuel swelling and porosity computation in the Sifgrs
#   fission gas behavior model for UO2 (UO2Sifgrs).
# As complementary to the fission gas release process, the fission gas
#   swelling is related to gas retention in the fuel in the form of bubbles.
#   Through a direct description of the gas bubble development, the fission
#   gas swelling and release are modeled as inherently coupled processes, on a
#   physical basis. Only the fission gas swelling due to grain-face bubbles is
#   considered.
# In a comprehensive treatment of fission gas release and fuel swelling, Sifgrs
#   also incorporates empirical models for the swelling due to solid fission
#   products and the fuel densification.
# Moreover, the different contributions to fuel porosity, namely, those due to
#   fabrication pores, gas bubbles (thus associated with fission gas swelling),
#   and sintering (densification), are computed consistently with the swelling
#   calculations. Then, the fuel total porosity in each mesh location can be
#   tracked (auxkernel PorosityAuxUO2), and considered in the computation of
#   other relevant material properties like the fuel thermal conductivity
#   (material model UO2Thermal).
# This test aims at demonstrating the above model capabilities. The considered
#   case involves a single-element cubic domain, constant temperature (1400 K)
#   and fission rate (1e19 f/(m**3s)), and a irradiation time of 1e8 s. The
#   Sifgrs model is adopted for calculating the fission gas release and fuel
#   swelling. Starting from a typical as-fabricated value of 5%, the fuel
#   porosity evolves consistently with the swelling. The fuel thermal
#   conductivity is calculated as coupled with porosity, which allows taking
#   into account the conductivity degradation due to progressive increase of
#   gaseous porosity (see also the attached file regression_tests_sifgrs.xlsx).

[GlobalParams]
  displacements = 'disp_x disp_y disp_z'
  volumetric_locking_correction = true
[]

[Mesh]
  [mesh]
    type = FileMeshGenerator
    file = cube_111.e
  []
[]

[Functions]
  [Temp_func]
    type = ParsedFunction
    expression = 1400.
  []
  [Fiss_func]
    type = ParsedFunction
    expression = 1.e19
  []
[]

[Variables]
  [temp]
    order = FIRST
    family = LAGRANGE
    initial_condition = 1400.
  []
  [disp_x]
    order = FIRST
    family = LAGRANGE
  []
  [disp_y]
    order = FIRST
    family = LAGRANGE
  []
  [disp_z]
    order = FIRST
    family = LAGRANGE
  []
[]

[AuxVariables]
  [fission_rate]
    order = FIRST
    family = LAGRANGE
  []
  [burnup]
    order = FIRST
    family = LAGRANGE
  []
  [porosity]
    order = CONSTANT
    family = MONOMIAL
    initial_condition = 0.05
  []
  [density]
    order = CONSTANT
    family = MONOMIAL
  []
  [deltav_v0_bubble_GB]
    order = CONSTANT
    family = MONOMIAL
  []
  [deltav_v0_sl]
    order = CONSTANT
    family = MONOMIAL
  []
  [deltav_v0_dn]
    order = CONSTANT
    family = MONOMIAL
  []
  [deltav_v0_swe]
    order = CONSTANT
    family = MONOMIAL
  []
  [thermal_conductivity]
    order = CONSTANT
    family = MONOMIAL
  []
  [GBCoverage]
    order = CONSTANT
    family = MONOMIAL
  []
  [intra_porosity]
    order = CONSTANT
    family = MONOMIAL
  []
  [gas_atom_conc]
    order = CONSTANT
    family = MONOMIAL
  []
  [rad_bbl_bdr]
    order = CONSTANT
    family = MONOMIAL
  []
  [GBresistance]
    order = CONSTANT
    family = MONOMIAL
  []
  [grain_radius]
    order = CONSTANT
    family = MONOMIAL
    initial_condition = 5e-6
  []
[]

[Physics/SolidMechanics/QuasiStatic]
  [pellets]
    strain = FINITE
    temperature = temp
    eigenstrain_names = 'fuel_thermal_strain fuel_volumetric_strain'
  []
[]

[Kernels]
  [heat]
    type = HeatConduction
    variable = temp
  []
[]

[AuxKernels]
  [frate]
    type = FissionRateGeneral
    fission_rate_formulation = GENERIC
    variable = fission_rate
    block = 1
    fission_rate_function = Fiss_func
    execute_on = 'initial timestep_begin'
  []
  [brnp]
    type = BurnupAux
    variable = burnup
    block = 1
    fission_rate = fission_rate
    density = 10417.
    execute_on = 'initial timestep_begin'
  []
  [por]
    type = PorosityAuxUO2
    block = 1
    variable = porosity
    execute_on = linear
  []
  [rho]
    type = MaterialRealAux
    variable = density
    property = density
    execute_on = 'initial timestep_end'
  []
  [dvv0bd]
    type = MaterialRealAux
    variable = deltav_v0_bubble_GB
    property = deltav_v0_bubble_GB
  []
  [dvv0swe]
    type = MaterialRealAux
    variable = deltav_v0_swe
    property = volumetric_swelling_strain
  []
  [thcond]
    type = MaterialRealAux
    variable = thermal_conductivity
    property = thermal_conductivity
    execute_on = 'initial timestep_end'
  []
  [GBCoverage]
    type = MaterialRealAux
    variable = GBCoverage
    property = GBCoverage
    execute_on = 'initial timestep_end'
  []
  [intra_porosity]
    type = MaterialRealAux
    variable = intra_porosity
    property = intra_porosity
  []
  [gas_atom_conc]
    type = MaterialRealAux
    variable = gas_atom_conc
    property = gas_atom_conc
  []
  [deltav_v0_dn]
    type = MaterialRealAux
    variable = deltav_v0_dn
    property = densification
  []
  [deltav_v0_sl]
    type = MaterialRealAux
    variable = deltav_v0_sl
    property = solid_swelling
  []
  [rad_bbl_bdr]
    type = MaterialRealAux
    variable = rad_bbl_bdr
    property = bubble_radius_GB
    execute_on = 'initial timestep_end'
  []
  [GBresistance]
    type = MaterialRealAux
    variable = GBresistance
    property = GBresistance
    execute_on = 'initial timestep_end'
  []
  # [grain_radius]
  #   type = GrainRadiusAux
  #   variable = grain_radius
  #   temperature = temp
  # []
[]

[BCs]
  [bottom_T]
    type = FunctionDirichletBC
    variable = temp
    function = Temp_func
    boundary = 1
  []
  [x_disp]
    type = DirichletBC
    variable = disp_x
    value = 0
    boundary = 1
  []
  [y_disp]
    type = DirichletBC
    variable = disp_y
    value = 0
    boundary = 2
  []
  [z_disp]
    type = DirichletBC
    variable = disp_z
    value = 0
    boundary = 3
  []
[]

[Materials]

  [swelling]
    type = UO2VolumetricSwellingEigenstrain
    block = 1
    burnup = burnup
    temperature = temp
    initial_fuel_density = 10417.0
    eigenstrain_name = fuel_volumetric_strain
  []

  [thermal_expansion]
    type = ComputeThermalExpansionEigenstrain
    block = 1
    thermal_expansion_coeff = 1.0e-5
    temperature = temp
    stress_free_temperature = 1400.0
    eigenstrain_name = fuel_thermal_strain
  []

  [elasticity_tensor]
    type = ComputeIsotropicElasticityTensor
    block = 1
    youngs_modulus = 2.0e11
    poissons_ratio = 0.3
  []

  [stress]
    type = ComputeFiniteStrainElasticStress
    block = 1
  []

  [density]
    type = StrainAdjustedDensity
    block = 1
    strain_free_density = 10417.0
  []
  [fission_gas_release_and_swelling]
    type = UO2Sifgrs
    block = 1
    temperature = temp
    fission_rate = fission_rate
    burnup = burnup
    initial_porosity = 0.05
  []
  [fuel_thermal_meso]
    type = UO2FissionGasThermal
    block = 1
    temperature = temp
    burnup = burnup
    grain_radius = 5e-6
  []
[]

[Executioner]
  type = Transient

  solve_type = 'PJFNK'

  l_tol = 1.e-04
  nl_abs_tol = 1.e-05
  nl_rel_tol = 1.e-05
  start_time = 0.
  num_steps = 100
  dt = 1.e+06
  end_time = 1.e+08
[]

[Postprocessors]
  [fis_gas_generated]
    type = ElementIntegralFisGasGeneratedSifgrs
    block = 1
  []
  [fis_gas_released]
    type = ElementIntegralFisGasReleasedSifgrs
    block = 1
  []
  [GBCov]
    type = ElementalVariableValue
    variable = GBCoverage
    elementid = 0
    execute_on = 'initial timestep_end'
  []
  [gas_atom_conc]
    type = ElementalVariableValue
    variable = gas_atom_conc
    elementid = 0
  []
  [thcond]
    type = ElementalVariableValue
    variable = thermal_conductivity
    elementid = 0
    execute_on = 'initial timestep_end'
  []
  [intra_porosity]
    type = ElementalVariableValue
    variable = intra_porosity
    elementid = 0
  []
  [rad_bbl_bdr]
    type = ElementalVariableValue
    variable = rad_bbl_bdr
    elementid = 0
    execute_on = 'initial timestep_end'
  []
  [GBresistance]
    type = ElementalVariableValue
    variable = GBresistance
    elementid = 0
    execute_on = 'initial timestep_end'
  []
[]

[Outputs]
  file_base = fissiongas
  csv = true
  [exodus]
    type = Exodus
  []
[]

(test/tests/meso_thcond_test/sifgrs_swelling_fissiongas_graingrowth.i)

# This test is for the fuel swelling and porosity computation in the Sifgrs
#   fission gas behavior model for UO2 (UO2Sifgrs).
# As complementary to the fission gas release process, the fission gas
#   swelling is related to gas retention in the fuel in the form of bubbles.
#   Through a direct description of the gas bubble development, the fission
#   gas swelling and release are modeled as inherently coupled processes, on a
#   physical basis. Only the fission gas swelling due to grain-face bubbles is
#   considered.
# In a comprehensive treatment of fission gas release and fuel swelling, Sifgrs
#   also incorporates empirical models for the swelling due to solid fission
#   products and the fuel densification.
# Moreover, the different contributions to fuel porosity, namely, those due to
#   fabrication pores, gas bubbles (thus associated with fission gas swelling),
#   and sintering (densification), are computed consistently with the swelling
#   calculations. Then, the fuel total porosity in each mesh location can be
#   tracked (auxkernel PorosityAuxUO2), and considered in the computation of
#   other relevant material properties like the fuel thermal conductivity
#   (material model UO2Thermal).
# This test aims at demonstrating the above model capabilities. The considered
#   case involves a single-element cubic domain, constant temperature (1400 K)
#   and fission rate (1e19 f/(m**3s)), and a irradiation time of 1e8 s. The
#   Sifgrs model is adopted for calculating the fission gas release and fuel
#   swelling. Starting from a typical as-fabricated value of 5%, the fuel
#   porosity evolves consistently with the swelling. The fuel thermal
#   conductivity is calculated as coupled with porosity, which allows taking
#   into account the conductivity degradation due to progressive increase of
#   gaseous porosity (see also the attached file regression_tests_sifgrs.xlsx).

[GlobalParams]
  displacements = 'disp_x disp_y disp_z'
  volumetric_locking_correction = true
[]

[Mesh]
  [mesh]
    type = FileMeshGenerator
    file = cube_111.e
  []
[]

[Functions]
  [Temp_func]
    type = ParsedFunction
    expression = 1400.
  []
  [Fiss_func]
    type = ParsedFunction
    expression = 1.e19
  []
[]

[Variables]
  [temp]
    order = FIRST
    family = LAGRANGE
    initial_condition = 1400.
  []
  [disp_x]
    order = FIRST
    family = LAGRANGE
  []
  [disp_y]
    order = FIRST
    family = LAGRANGE
  []
  [disp_z]
    order = FIRST
    family = LAGRANGE
  []
[]

[AuxVariables]
  [fission_rate]
    order = FIRST
    family = LAGRANGE
  []
  [burnup]
    order = FIRST
    family = LAGRANGE
  []
  [porosity]
    order = CONSTANT
    family = MONOMIAL
    initial_condition = 0.05
  []
  [density]
    order = CONSTANT
    family = MONOMIAL
  []
  [deltav_v0_bubble_GB]
    order = CONSTANT
    family = MONOMIAL
  []
  [deltav_v0_sl]
    order = CONSTANT
    family = MONOMIAL
  []
  [deltav_v0_dn]
    order = CONSTANT
    family = MONOMIAL
  []
  [deltav_v0_swe]
    order = CONSTANT
    family = MONOMIAL
  []
  [thermal_conductivity]
    order = CONSTANT
    family = MONOMIAL
  []
  [GBCoverage]
    order = CONSTANT
    family = MONOMIAL
  []
  [intra_porosity]
    order = CONSTANT
    family = MONOMIAL
  []
  [gas_atom_conc]
    order = CONSTANT
    family = MONOMIAL
  []
  [rad_bbl_bdr]
    order = CONSTANT
    family = MONOMIAL
  []
  [GBresistance]
    order = CONSTANT
    family = MONOMIAL
  []
  [grain_radius]
    order = CONSTANT
    family = MONOMIAL
    initial_condition = 5e-6
  []
[]

[Physics/SolidMechanics/QuasiStatic]
  [pellets]
    strain = FINITE
    temperature = temp
    eigenstrain_names = 'fuel_thermal_strain fuel_volumetric_strain'
  []
[]

[Kernels]
  [heat]
    type = HeatConduction
    variable = temp
  []
[]

[AuxKernels]
  [frate]
    type = FissionRateGeneral
    fission_rate_formulation = GENERIC
    variable = fission_rate
    block = 1
    fission_rate_function = Fiss_func
    execute_on = 'initial timestep_begin'
  []
  [brnp]
    type = BurnupAux
    variable = burnup
    block = 1
    fission_rate = fission_rate
    density = 10417.
    execute_on = 'initial timestep_begin'
  []
  [por]
    type = PorosityAuxUO2
    block = 1
    variable = porosity
    execute_on = linear
  []
  [rho]
    type = MaterialRealAux
    variable = density
    property = density
    execute_on = 'initial timestep_end'
  []
  [dvv0bd]
    type = MaterialRealAux
    variable = deltav_v0_bubble_GB
    property = deltav_v0_bubble_GB
  []
  [dvv0swe]
    type = MaterialRealAux
    variable = deltav_v0_swe
    property = volumetric_swelling_strain
  []
  [thcond]
    type = MaterialRealAux
    variable = thermal_conductivity
    property = thermal_conductivity
    execute_on = 'initial timestep_end'
  []
  [GBCoverage]
    type = MaterialRealAux
    variable = GBCoverage
    property = GBCoverage
    execute_on = 'initial timestep_end'
  []
  [intra_porosity]
    type = MaterialRealAux
    variable = intra_porosity
    property = intra_porosity
  []
  [gas_atom_conc]
    type = MaterialRealAux
    variable = gas_atom_conc
    property = gas_atom_conc
  []
  [deltav_v0_dn]
    type = MaterialRealAux
    variable = deltav_v0_dn
    property = densification
  []
  [deltav_v0_sl]
    type = MaterialRealAux
    variable = deltav_v0_sl
    property = solid_swelling
  []
  [rad_bbl_bdr]
    type = MaterialRealAux
    variable = rad_bbl_bdr
    property = bubble_radius_GB
    execute_on = 'initial timestep_end'
  []
  [GBresistance]
    type = MaterialRealAux
    variable = GBresistance
    property = GBresistance
    execute_on = 'initial timestep_end'
  []
  [grain_radius]
    type = GrainRadiusAux
    variable = grain_radius
    temperature = temp
  []
[]

[BCs]
  [bottom_T]
    type = FunctionDirichletBC
    variable = temp
    function = Temp_func
    boundary = 1
  []
  [x_disp]
    type = DirichletBC
    variable = disp_x
    value = 0
    boundary = 1
  []
  [y_disp]
    type = DirichletBC
    variable = disp_y
    value = 0
    boundary = 2
  []
  [z_disp]
    type = DirichletBC
    variable = disp_z
    value = 0
    boundary = 3
  []
[]

[Materials]

  [swelling]
    type = UO2VolumetricSwellingEigenstrain
    block = 1
    burnup = burnup
    temperature = temp
    initial_fuel_density = 10417.0
    eigenstrain_name = fuel_volumetric_strain
  []

  [thermal_expansion]
    type = ComputeThermalExpansionEigenstrain
    block = 1
    thermal_expansion_coeff = 1.0e-5
    temperature = temp
    stress_free_temperature = 1400.0
    eigenstrain_name = fuel_thermal_strain
  []

  [elasticity_tensor]
    type = ComputeIsotropicElasticityTensor
    block = 1
    youngs_modulus = 2.0e11
    poissons_ratio = 0.3
  []

  [stress]
    type = ComputeFiniteStrainElasticStress
    block = 1
  []

  [density]
    type = StrainAdjustedDensity
    block = 1
    strain_free_density = 10417.0
  []
  [fission_gas_release_and_swelling]
    type = UO2Sifgrs
    block = 1
    temperature = temp
    fission_rate = fission_rate
    burnup = burnup
    initial_porosity = 0.05
  []
  [fuel_thermal_meso]
    type = UO2FissionGasThermal
    block = 1
    temperature = temp
    burnup = burnup
    grain_radius = grain_radius
  []
[]

[Executioner]
  type = Transient

  solve_type = 'PJFNK'

  l_tol = 1.e-04
  nl_abs_tol = 1.e-05
  nl_rel_tol = 1.e-05
  start_time = 0.
  num_steps = 100
  dt = 1.e+06
  end_time = 1.e+08
[]

[Postprocessors]
  [fis_gas_generated]
    type = ElementIntegralFisGasGeneratedSifgrs
    block = 1
  []
  [fis_gas_released]
    type = ElementIntegralFisGasReleasedSifgrs
    block = 1
  []
  [GBCov]
    type = ElementalVariableValue
    variable = GBCoverage
    elementid = 0
    execute_on = 'initial timestep_end'
  []
  [gas_atom_conc]
    type = ElementalVariableValue
    variable = gas_atom_conc
    elementid = 0
  []
  [thcond]
    type = ElementalVariableValue
    variable = thermal_conductivity
    elementid = 0
    execute_on = 'initial timestep_end'
  []
  [intra_porosity]
    type = ElementalVariableValue
    variable = intra_porosity
    elementid = 0
  []
  [rad_bbl_bdr]
    type = ElementalVariableValue
    variable = rad_bbl_bdr
    elementid = 0
    execute_on = 'initial timestep_end'
  []
  [GBresistance]
    type = ElementalVariableValue
    variable = GBresistance
    elementid = 0
    execute_on = 'initial timestep_end'
  []
[]

[Outputs]
  file_base = graingrowth
  csv = true
  [exodus]
    type = Exodus
  []
[]

(test/tests/meso_thcond_test/sifgrs_swelling_fissiongas.i)

# This test is for the fuel swelling and porosity computation in the Sifgrs
#   fission gas behavior model for UO2 (UO2Sifgrs).
# As complementary to the fission gas release process, the fission gas
#   swelling is related to gas retention in the fuel in the form of bubbles.
#   Through a direct description of the gas bubble development, the fission
#   gas swelling and release are modeled as inherently coupled processes, on a
#   physical basis. Only the fission gas swelling due to grain-face bubbles is
#   considered.
# In a comprehensive treatment of fission gas release and fuel swelling, Sifgrs
#   also incorporates empirical models for the swelling due to solid fission
#   products and the fuel densification.
# Moreover, the different contributions to fuel porosity, namely, those due to
#   fabrication pores, gas bubbles (thus associated with fission gas swelling),
#   and sintering (densification), are computed consistently with the swelling
#   calculations. Then, the fuel total porosity in each mesh location can be
#   tracked (auxkernel PorosityAuxUO2), and considered in the computation of
#   other relevant material properties like the fuel thermal conductivity
#   (material model UO2Thermal).
# This test aims at demonstrating the above model capabilities. The considered
#   case involves a single-element cubic domain, constant temperature (1400 K)
#   and fission rate (1e19 f/(m**3s)), and a irradiation time of 1e8 s. The
#   Sifgrs model is adopted for calculating the fission gas release and fuel
#   swelling. Starting from a typical as-fabricated value of 5%, the fuel
#   porosity evolves consistently with the swelling. The fuel thermal
#   conductivity is calculated as coupled with porosity, which allows taking
#   into account the conductivity degradation due to progressive increase of
#   gaseous porosity (see also the attached file regression_tests_sifgrs.xlsx).

[GlobalParams]
  displacements = 'disp_x disp_y disp_z'
  volumetric_locking_correction = true
[]

[Mesh]
  [mesh]
    type = FileMeshGenerator
    file = cube_111.e
  []
[]

[Functions]
  [Temp_func]
    type = ParsedFunction
    expression = 1400.
  []
  [Fiss_func]
    type = ParsedFunction
    expression = 1.e19
  []
[]

[Variables]
  [temp]
    order = FIRST
    family = LAGRANGE
    initial_condition = 1400.
  []
  [disp_x]
    order = FIRST
    family = LAGRANGE
  []
  [disp_y]
    order = FIRST
    family = LAGRANGE
  []
  [disp_z]
    order = FIRST
    family = LAGRANGE
  []
[]

[AuxVariables]
  [fission_rate]
    order = FIRST
    family = LAGRANGE
  []
  [burnup]
    order = FIRST
    family = LAGRANGE
  []
  [porosity]
    order = CONSTANT
    family = MONOMIAL
    initial_condition = 0.05
  []
  [density]
    order = CONSTANT
    family = MONOMIAL
  []
  [deltav_v0_bubble_GB]
    order = CONSTANT
    family = MONOMIAL
  []
  [deltav_v0_sl]
    order = CONSTANT
    family = MONOMIAL
  []
  [deltav_v0_dn]
    order = CONSTANT
    family = MONOMIAL
  []
  [deltav_v0_swe]
    order = CONSTANT
    family = MONOMIAL
  []
  [thermal_conductivity]
    order = CONSTANT
    family = MONOMIAL
  []
  [GBCoverage]
    order = CONSTANT
    family = MONOMIAL
  []
  [intra_porosity]
    order = CONSTANT
    family = MONOMIAL
  []
  [gas_atom_conc]
    order = CONSTANT
    family = MONOMIAL
  []
  [rad_bbl_bdr]
    order = CONSTANT
    family = MONOMIAL
  []
  [GBresistance]
    order = CONSTANT
    family = MONOMIAL
  []
  [grain_radius]
    order = CONSTANT
    family = MONOMIAL
    initial_condition = 5e-6
  []
[]

[Physics/SolidMechanics/QuasiStatic]
  [pellets]
    strain = FINITE
    temperature = temp
    eigenstrain_names = 'fuel_thermal_strain fuel_volumetric_strain'
  []
[]

[Kernels]
  [heat]
    type = HeatConduction
    variable = temp
  []
[]

[AuxKernels]
  [frate]
    type = FissionRateGeneral
    fission_rate_formulation = GENERIC
    variable = fission_rate
    block = 1
    fission_rate_function = Fiss_func
    execute_on = 'initial timestep_begin'
  []
  [brnp]
    type = BurnupAux
    variable = burnup
    block = 1
    fission_rate = fission_rate
    density = 10417.
    execute_on = 'initial timestep_begin'
  []
  [por]
    type = PorosityAuxUO2
    block = 1
    variable = porosity
    execute_on = linear
  []
  [rho]
    type = MaterialRealAux
    variable = density
    property = density
    execute_on = 'initial timestep_end'
  []
  [dvv0bd]
    type = MaterialRealAux
    variable = deltav_v0_bubble_GB
    property = deltav_v0_bubble_GB
  []
  [dvv0swe]
    type = MaterialRealAux
    variable = deltav_v0_swe
    property = volumetric_swelling_strain
  []
  [thcond]
    type = MaterialRealAux
    variable = thermal_conductivity
    property = thermal_conductivity
    execute_on = 'initial timestep_end'
  []
  [GBCoverage]
    type = MaterialRealAux
    variable = GBCoverage
    property = GBCoverage
    execute_on = 'initial timestep_end'
  []
  [intra_porosity]
    type = MaterialRealAux
    variable = intra_porosity
    property = intra_porosity
  []
  [gas_atom_conc]
    type = MaterialRealAux
    variable = gas_atom_conc
    property = gas_atom_conc
  []
  [deltav_v0_dn]
    type = MaterialRealAux
    variable = deltav_v0_dn
    property = densification
  []
  [deltav_v0_sl]
    type = MaterialRealAux
    variable = deltav_v0_sl
    property = solid_swelling
  []
  [rad_bbl_bdr]
    type = MaterialRealAux
    variable = rad_bbl_bdr
    property = bubble_radius_GB
    execute_on = 'initial timestep_end'
  []
  [GBresistance]
    type = MaterialRealAux
    variable = GBresistance
    property = GBresistance
    execute_on = 'initial timestep_end'
  []
  # [grain_radius]
  #   type = GrainRadiusAux
  #   variable = grain_radius
  #   temperature = temp
  # []
[]

[BCs]
  [bottom_T]
    type = FunctionDirichletBC
    variable = temp
    function = Temp_func
    boundary = 1
  []
  [x_disp]
    type = DirichletBC
    variable = disp_x
    value = 0
    boundary = 1
  []
  [y_disp]
    type = DirichletBC
    variable = disp_y
    value = 0
    boundary = 2
  []
  [z_disp]
    type = DirichletBC
    variable = disp_z
    value = 0
    boundary = 3
  []
[]

[Materials]

  [swelling]
    type = UO2VolumetricSwellingEigenstrain
    block = 1
    burnup = burnup
    temperature = temp
    initial_fuel_density = 10417.0
    eigenstrain_name = fuel_volumetric_strain
  []

  [thermal_expansion]
    type = ComputeThermalExpansionEigenstrain
    block = 1
    thermal_expansion_coeff = 1.0e-5
    temperature = temp
    stress_free_temperature = 1400.0
    eigenstrain_name = fuel_thermal_strain
  []

  [elasticity_tensor]
    type = ComputeIsotropicElasticityTensor
    block = 1
    youngs_modulus = 2.0e11
    poissons_ratio = 0.3
  []

  [stress]
    type = ComputeFiniteStrainElasticStress
    block = 1
  []

  [density]
    type = StrainAdjustedDensity
    block = 1
    strain_free_density = 10417.0
  []
  [fission_gas_release_and_swelling]
    type = UO2Sifgrs
    block = 1
    temperature = temp
    fission_rate = fission_rate
    burnup = burnup
    initial_porosity = 0.05
  []
  [fuel_thermal_meso]
    type = UO2FissionGasThermal
    block = 1
    temperature = temp
    burnup = burnup
    grain_radius = 5e-6
  []
[]

[Executioner]
  type = Transient

  solve_type = 'PJFNK'

  l_tol = 1.e-04
  nl_abs_tol = 1.e-05
  nl_rel_tol = 1.e-05
  start_time = 0.
  num_steps = 100
  dt = 1.e+06
  end_time = 1.e+08
[]

[Postprocessors]
  [fis_gas_generated]
    type = ElementIntegralFisGasGeneratedSifgrs
    block = 1
  []
  [fis_gas_released]
    type = ElementIntegralFisGasReleasedSifgrs
    block = 1
  []
  [GBCov]
    type = ElementalVariableValue
    variable = GBCoverage
    elementid = 0
    execute_on = 'initial timestep_end'
  []
  [gas_atom_conc]
    type = ElementalVariableValue
    variable = gas_atom_conc
    elementid = 0
  []
  [thcond]
    type = ElementalVariableValue
    variable = thermal_conductivity
    elementid = 0
    execute_on = 'initial timestep_end'
  []
  [intra_porosity]
    type = ElementalVariableValue
    variable = intra_porosity
    elementid = 0
  []
  [rad_bbl_bdr]
    type = ElementalVariableValue
    variable = rad_bbl_bdr
    elementid = 0
    execute_on = 'initial timestep_end'
  []
  [GBresistance]
    type = ElementalVariableValue
    variable = GBresistance
    elementid = 0
    execute_on = 'initial timestep_end'
  []
[]

[Outputs]
  file_base = fissiongas
  csv = true
  [exodus]
    type = Exodus
  []
[]

Description
Example Input Syntax
Input Parameters
Input Files
References