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Add eVinci like model
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refs idaholab#470
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GiudGiud committed Nov 11, 2024
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128 changes: 128 additions & 0 deletions doc/content/microreactors/gHPMR/gHPMR_mesh.md
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# 2D Generic Heat Pipe Microreactor (gHPMR) Model Mesh

!alert warning
This meshing script generates a mesh in a coarse form. Convergence studies for the physics of interest should be performed by the user.

The 2D generic Heat Pipe Microreactor (gHPMR) Model Mesh is created in several steps:

1. The fuel pin cell and heat pipe pin cell meshes are generated.

2. The fuel assembly meshes are created.

3. The core mesh is generated from the lattice of assembly meshes.

4. The control drum meshes are generated and translated to account for each drum position and placement in the core.

5. The reflector mesh is generated.

6. The final 2D core mesh is generated including outer reactor vessel boundary.

A more detailed explanation of each step follows below.

## Fuel Pin Cell Meshes

First, there are 5 fuel pin meshes that are generated - 4 are for assemblies without a control rod channel and 1 for an assembly with a control rod channel.

!listing microreactors/gHPMR/2D_gHPMR_Final.i start=[fuel_pin_R0] end=[heat_pipe_pin]

!media media/gHPMR/fuel_pins.png
style=width:75%;margin:auto;
caption=Figure 1: The five 2D fuel pin cell meshes; the yellow pin mesh is the pin used in the fuel assembly which contains a control rod channel.

Then a pin cell mesh is generated for the heat pipe.

!listing microreactors/gHPMR/2D_gHPMR_Final.i block=Mesh/heat_pipe_pin

!media media/gHPMR/heat_pipe_pin.png
style=width:50%;margin:auto;
caption=Figure 2: The 2D heat pipe pin cell mesh.

Two fake pin cell meshes are generated for the purpose of deletion in future steps.

!listing microreactors/gHPMR/2D_gHPMR_Final.i start=[fake_pin] end=[assembly1_R0]

## Fuel Assembly

Fuel Pin assemblies are then generated for each of the 5 fuel pin meshes.

The fuel pin cell assembly is generated using the previous step's pin cell meshes. The fake pin cells are then deleted from the assembly mesh in order to create a void for the heat pipe meshes in future steps. The outer assembly boundary is generated. Boundary ids are renamed and meta data is added back to the assembly mesh. This process is repeated for the four other fuel assemblies.

!alert note title=Metadata
When the hexagonal meshes are modified, they lose the original metadata. Thus reapplying the metadata from before the modifications is necessary to generate the assemblies.

!listing microreactors/gHPMR/2D_gHPMR_Final.i start=[assembly1_R0] end=[assembly3]

!media media/gHPMR/fuel_assemblies.png
style=width:100%;margin:auto;
caption=Figure 3: The identical 2D fuel assembly meshes; heat pipe pin cell meshes are in green and the fuel pin cell meshes are in red.

The last fuel pin assembly mesh generated includes a control rod channel. The same steps as above are followed, but block ids must be assigned to the larger, to be deleted, void region before being meshed. Then the control rod hole is carved and stitched back to the hexagonal assembly mesh.

!listing microreactors/gHPMR/2D_gHPMR_Final.i start=[assembly3] end=[core1]

!media media/gHPMR/fuel_assembly_CR.png
style=width:60%;margin:auto;
caption=Figure 4: The 2D fuel assembly mesh containing a control rod channel in the center; heat pipe pin cell meshes are in green and the fuel pin cell meshes are in red.

## Hexagonal Core Assembly

The hexagonal core assembly mesh is generated using the previous step's fuel pin assembly meshes. The block ids are renamed to separate the monolith triangular elements. Then the outer core ring boundary is created.

!listing microreactors/gHPMR/2D_gHPMR_Final.i start=[core1] end=[control_drum_base]

!media media/gHPMR/hex_core.png
style=width:60%;margin:auto;
caption=Figure 5: The 2D hexagonal core assembly mesh.

## Control Drum Meshes

The meshes for the 12 control drums are then generated. The control drum base mesh is first generated, then the outer polygon area is deleted to keep only the circular control drum.

!listing microreactors/gHPMR/2D_gHPMR_Final.i start=[control_drum_base] end=[control_drum_S1_A]

The control drum mesh is rotated then translated multiple times to account for every position and placement of the drums in the core.

!listing microreactors/gHPMR/2D_gHPMR_Final.i start=[control_drum_S1_A] end=[reflector_polygon]

!media media/gHPMR/control_drums.png
style=width:75%;margin:auto;
caption=Figure 6: Six control rods with the different orientations.

## Reflector Mesh

The mesh for the reflector is generated using polygons in an effort to reduce areas meshed in future steps. The mesh is then translated several times to account for every position and placement of reflectors in the core.

!listing microreactors/gHPMR/2D_gHPMR_Final.i start=[reflector_polygon] end=[outer_core_mesh]

<!-- !media media/gHPMR/reflector_mesh.png
style=width:55%;margin:auto;
caption=Figure 7: The 2D reflector mesh. -->

## Outer Core Mesh

Lastly, the core mesh is merged with the control drum and reflector meshes to generate a final core mesh which includes the outer core area. Block ids are renamed to keep triangular and quadrilateral elements separate. The outer vessel mesh is generated and sidesets are added to specify the radial boundary of the reactor vessel.

!listing microreactors/gHPMR/2D_gHPMR_Final.i start=[outer_core_mesh] end=final_generator

!media media/gHPMR/final_core.png
style=width:65%;margin:auto;
caption=Figure 8: The 2D final core assembly mesh featuring 12 control drums, exterior reactor vessel ring in red, fuel assemblies in yellow, and fuel assemblies with control rod channels in pink.

!media media/gHPMR/final_core_closeup.png
style=width:75%;margin:auto;
caption=Figure 9: Closeup of the 2D final core assembly mesh featuring control drums in gray and fuel assemblies with and without control rod channels.


## Extrusion to 3D Specifications

The spacial discretization specifications are summarized below.

!table id=table-floating caption=The 2D mesh can be extruded to form a 3D mesh. Table 1 summarizes the extrusion specifications in the gHPMR model, from [!cite](gHPMR_main).
| Spacial Discretization | Value |
|:------------------------------------------------|:-----------------------------------|
| Number of Axial Elements in Evaporator Section | 18 |
| Number of Axial Elements in Adiabatic Section | 4 |
| Number of Axial Elements in Condenser Section | 18 |
| Number of Radial Elements in Wick Region | 2 |
| Number of Radial Elements in Annular Gap Region | 2 |
| Number of Radial Elements in Cladding Region | 2 |
64 changes: 64 additions & 0 deletions doc/content/microreactors/gHPMR/gHPMR_reactor_description.md
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# Generic Heat Pipe Microreactor (gHPMR) Model Reactor Description

The generic Heat Pipe Microreactor (gHPMR) Model is based on &copy; Westinghouse Electric Company's eVinci microreactor design. The &copy; eVinci design has potential for autonomous operation, is intended for factory fabrication, and has a lifetime of 10 years, after which the entire reactor would be returned to the factory for either refueling or storage [!cite](eVinci).

Fuel, moderator, and heat pipes are arranged in a hexagonal lattice. The hexagonal core sits in a steel monolith. The monolithic microreactor concept utilizes a monolithic metal structure to support the fuel assemblies and evaporator sections of the heat pipes. Control drums are embedded inside the radial reflector sections. A central rod is used to start up and shut down the reactor. Sodium is utilized as the heat pipe working fluid. Heat pipes protrude from both ends of the core, allowing for two primary heat exchangers, one at each end of the monolith. Power conversion is achieved by using a supercritical carbon dioxide Brayton turbine or Stirling engines [!cite](eVinci).

Below are the design specifications for the gHPMR model.

!table id=table-floating caption=Design specifications for the gHPMR model, from [!cite](gHPMR_main).
| General Design Specifications | Value |
|:----------------------------------------------|:-------------------------------------|
| Thermal Power | 15 MW(th) |
| Core Height | 1.8 m |
| Core Height (Active) | 1.6 m |
| Reflector Height | 0.2 m |
| Core Radius | 1.4 m |
| Canister Radius | 1.468 m |
| Fuel Enrichment | 10 w / o |
| Number of Heat Pipes | 876 |
| Number of Fuel Assemblies Types | 2 |
| Number of Standard Fuel Assemblies | 114 |
| Number of Control Rod Fuel Assemblies | 13 |
| Fuel Assembly Pitch | 17.368 cm |
| Pin Pitch | 2.782 cm |
| Fuel Compact Hole Radius | 0.95 cm |
| Heat Pipe Hold Radius | 1.07 cm |
| Number of Control Drums | 12 |
| Control Drum Diameter | 28.1979 cm |
| Control Drum B${_4}$C Layer Thickness | 2.7984 cm |
| Control Drum B${_4}$C Angular Extension | 120$^{\circ}$ |

| Heat Pipe Specifications | Value |
|:----------------------------------------------|:-------------------------------------|
| Working Fluid | Sodium |
| Wick Material | SS 316 |
| Cladding Material | SS 316 |
| Evaporator Length | 1.8 m |
| Adiabatic Length | 0.4 m |
| Condenser Length | 1.8 m |
| Outer Cladding Radius | 0.0105 m |
| Inner Cladding Radius | 0.0097 m |
| Outer Wick Radius | 0.0090 m |
| Inner Wick Radius | 0.0080 m |
| Wick Porosity | 0.7 |
| Wick Permeability | 2E-9 m$^{2}$ |
| Pore Radius | 1E-9 m |
| Wick Fill | 100% overfill by volume at 500 K |

| Compact and TRISO Specifications | Value |
|:----------------------------------------------|:-------------------------------------|
| Compact Fueled Zone Radius | 0.875 cm |
| Compact Non-Fueled Zone Radius | 0.9 cm |
| Compact Packing Fraction | 40% |
| UCO Kernel Radius | 0.02125 cm |
| Buffer Radius | 0.03125 cm |
| Inner PyC Radius | 0.03525 cm |
| SiC Radius | 0.03875 cm |
| Outer PyC Radius | 0.04275 cm |

| Operating Conditions | Value |
|:-----------------------------------------------|:------------------------------------|
| Average Temperature | 1073.15 K |
| Condenser Convection Temperature | 523.15 K |
| Condenser Convection heat transfer coefficient | 312.4 W/(m$^{2}$ - K) |
15 changes: 15 additions & 0 deletions doc/content/microreactors/gHPMR/index.md
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# 2D gHPMR Reactor Model

!tag name=gHPMR Model pairs=reactor_type:gHPMR
reactor:gHPMR
geometry:annular
codes_used:Griffin;SAM;Sockeye
computing_needs:HPC
fiscal_year:2024
sponsor:NEAMS
institution:INL;ANL
simulation_type:mesh-only

[2D gHPMR Model Reactor Description](gHPMR_reactor_description.md)

[2D gHPMR Model Mesh](gHPMR_mesh.md)
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