FIPDRodletMeshGenerator

Description

The FIPDRodletMeshGenerator generates a smeared pellet mesh of a fuel pin (fuel slug + cladding) irradiated in EBR-II as part of the Integral Faster Reactor (IFR) program, based on the fuel pin design geometry file available at the EBR-II Fuels Irradiation & Physics Database (FIPD)(Yacout et al. (2021)).

Figure 1: A schematic drawing showing the pin geometry parameters in RodletMeshGenerator that are important for metallic fuel pins.

In order to get the necessary fuel pin geometry parameters needed for mesh generation (see Figure 1), pin design data available in FIPD can be used by downloading the geometry CSV file. A pin design geometry CSV file from FIPD contains two columns. The first column lists the names of design geometry parameters, while the second column lists the corresponding values. If a parameter is missing, the second column for that parameter is empty. There are three sources for these pin design geometry parameters: nominal design parameters (the n_xyz parameters), as-built design parameters (the ab_xyz parameters), and measured design parameters (the m_xyz parameters). When a design parameter is available from multiple sources, a priority list is needed to determine which source is used for mesh generation, which is discussed as follows:

From an FIPD pin design CSV file, six parameters need to be collected to form a complete set of geometry data for mesh generation: (1) cladding outer diameter (OD); (2) cladding thickness; (3) fuel slug length; (4) fuel slug OD; (5) sodium level above slug top; and (6) plenum volume.

Parameters (1), (2), and (5) are only available in as-built and nominal sources. The parameters from the two sources are quite consistent with each other. Therefore, the following priority is used for mesh generation: as-built>nominal. Optionally, users can use vector parameters clad_outer_diameter_priority, clad_thickness_priority, and sodium_level_priority to define custom priorities. For example, the default values for these vector parameters are all 'as-built nominal'.

Parameter (3) is available in all three sources. Parameter (3) from these sources are reasonably consistent with each other except for some outliers from measured source, which will need to be investigated in the ongoing FIPD quality assurance (QA) effort. At this moment, the following priority is used for mesh generation: as-built>nominal>measured. This priority is subject to change once the QA is completed. Optionally, users can use the vector parameter fuel_length_priority to define a custom priority. For example, the default value for this vector parameter is 'as-built nominal measured'.

Parameter (4) is available in all three sources. The current version of measured parameters only have two-decimal precision, while the as-built and nominal parameters have three-decimal precision. Thus, the following priority is used for mesh generation: as-built>nominal>measured. Optionally, users can use the vector parameter fuel_diameter_priority to define a custom priority. For example, the default value for this vector parameter is 'as-built nominal measured'.

Parameter (6) can either be directly adopted from ab_spec_plenum_volume_25C_cm3, or deduced from fuel slug volume (fuel slug OD and length) and plenum-to-fuel ratio. The plenum-to-fuel ratio is available in both as-built and nominal sources. For the majority of the fuel pins in FIPD, parameters (6) from the three aforementioned sources are consistent. For X441, the ab_spec_plenum_volume_25C_cm3 may have some outlier values. As a result, the following priority is used for mesh generation: as-built-plenum-to-fuel>nominal-plenum-to-fuel>as-built-plenum-volume. Optionally, users can use the vector parameter plenum_volume_priority to define a custom priority. For example, the default value for this vector parameter is 'as-built-plenum-to-fuel nominal-plenum-to-fuel as-built-plenum-volume'.

In addition to the FIPD pin design data file, FIPDRodletMeshGenerator also provides an option to import axial dependent as-fabricated fuel diameter measurement data from a CSV file specified by fipd_as_fabricated_file. Such CSV files are available on FIPD only for a selection of fuel pins. Based on the axial dependent fuel diameters from the CSV file, spline interpolation is used to shape the outer radial surface of the fuel slug. This would also override the fuel slug OD information from the pin design data file.

The FIPDRodletMeshGenerator also creates a series of metadata, which can be accessed by other objects through MeshMetaDataInterface to ensure the consistency of pin design geometry parameters throughout the simulation. The current available metadata are listed as follows:

Additionally, FIPDRodletMeshGenerator can also optionally create cap and stand regions as RodletMeshGenerator does.

[Mesh<<<{"href": "../../syntax/Mesh/index.html"}>>>]
  [gen]
    type = FIPDRodletMeshGenerator<<<{"description": "Creates a 2D-RZ axisymmetric mesh of a fuel rod using an FIPD geometry file.", "href": "FIPDRodletMeshGenerator.html"}>>>
    fipd_geom_file<<<{"description": "File containing geometry data of fuel pin from FIPD."}>>> = fipd_pin_design/DP11_design.csv
    gap_bottom_length<<<{"description": "Length of gap between bottom of fuel and inside bottom surface of cladding"}>>> = 0.31e-3 # arbitrary
    cladding_bottom_plug_length<<<{"description": "Length of bottom cladding plug"}>>> = 2.24e-3 # arbitrary
    cladding_top_plug_length<<<{"description": "Length of top cladding plug"}>>> = 2.24e-3 # arbitrary
    cladding_sidewall_radial_elements<<<{"description": "Number of radial elements in the cladding sidewall"}>>> = 2
    cladding_sidewall_axial_element_numbers<<<{"description": "List of number of elements within the intervals in 'cladding_sidewall_axial_element_intervals'. The length of this list must be one less than 'cladding_sidewall_axial_element_intervals'."}>>> = '2 4 4'
    cladding_top_plug_radial_elements<<<{"description": "Number of radial elements in the top cladding plug"}>>> = 4
    cladding_top_plug_axial_elements<<<{"description": "Number of radial elements in the top cladding plug"}>>> = 2
    cladding_bottom_plug_radial_elements<<<{"description": "Number of radial elements in the bottom cladding plug"}>>> = 4
    cladding_bottom_plug_axial_elements<<<{"description": "Number of radial elements in the bottom cladding plug"}>>> = 2
    fuel_radial_elements<<<{"description": "Number of radial elements in the fuel"}>>> = 4
    fuel_axial_element_intervals<<<{"description": "List of relative locations of intervals in the fuel length for which to set a specific number of elements. List must start with 0 and end with 1."}>>> = '0 0.25 1'
    fuel_axial_element_numbers<<<{"description": "List of number of elements within the intervals in 'fuel_axial_element_intervals'. The length of this list must be one less than 'fuel_axial_element_intervals'."}>>> = '4 2'
    use_default_cladding_sidewall_axial_element_intervals<<<{"description": "A Boolean parameter to decide is a a trivial set of cladding sidewall axial element intervals (i.e., hollow cladding bottom, fuel slug bottom, fuel slug top, and hollow cladding top) is used."}>>> = true
    elem_type<<<{"description": "The type of element from libMesh to generate for the regions to be meshed by quadrilateral elements. If applicable, TRI3 elements are used for the regions to be meshed by triangular elements if QUAD4 is selected here, whereas TRI6 elements are used if QUAD8/QUAD9 is selected "}>>> = QUAD4
  []
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Input Parameters

Input Files

• (test/tests/fipd_rodlet_mesh_generator/fipd_rodlet_mesh_generator.i)
• (assessment/metallic_fuel/FBTA/analysis/fbta_run/FBTA_base.i)
• (assessment/metallic_fuel/FBTA/analysis/steady_state/common_inputs/test_base.i)
• (assessment/metallic_fuel/EBRII/X447/analysis/enhancement/x447_enh_base.i)
• (test/tests/fipd_axial_pie_comparison/fipd_pie_vpp_fuel.i)
• (test/tests/sodium_coolant_channel/dp11.i)
• (test/tests/upuzr_fission_rate/test_meta_ad.i)
• (test/tests/fipd_rodlet_mesh_generator/fipd_rodlet_mesh_generator_puzr_den.i)
• (test/tests/fipd_rodlet_mesh_generator/fipd_rodlet_mesh_generator_custom.i)
• (test/tests/metallic_fuel_cladding_degradation/test_id_meshmetadata.i)
• (assessment/metallic_fuel/EBRII/X423/analysis/x423_vp_base.i)
• (test/tests/fipd_axial_pie_comparison/fipd_pie_vpp_clad.i)
• (test/tests/fipd_rodlet_mesh_generator/fipd_rodlet_mesh_generator_err.i)
• (test/tests/fipd_axial_profile_function/test_peak_meshmetadata.i)
• (test/tests/upuzr_fission_rate/test_meta.i)
• (assessment/metallic_fuel/WPF/analysis/X425_T418/X425_base.i)
• (assessment/metallic_fuel/FBTA/analysis/steady_state/AK181/181193/IFR1_181193.i)
• (assessment/metallic_fuel/WPF/analysis/FM-1/FM_base.i)
• (test/tests/fipd_rodlet_mesh_generator/fipd_rodlet_mesh_generator_clad.i)
• (test/tests/fission_rate/meta.i)
• (test/tests/fipd_rodlet_mesh_generator/fipd_rodlet_mesh_generator_puzr_bu.i)
• (test/tests/fipd_rodlet_mesh_generator/fipd_rodlet_mesh_generator_vol.i)
• (assessment/metallic_fuel/EBRII/X423/analysis/x423_lm_base.i)
• (test/tests/metallic_fuel_melting_function/test_general_metadata.i)
• (test/tests/fission_rate/ad_meta.i)
• (assessment/metallic_fuel/EBRII/X447/analysis/legacy/x447_base.i)

References