Add random_ray_pincell() example model (#3735)

Co-authored-by: John Tramm <john.tramm@gmail.com>
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Olek 2026-01-23 10:20:25 -06:00 committed by GitHub
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@ -4,7 +4,7 @@ import numpy as np
import openmc
PINCELL_PITCH = 1.26 # cm
def pwr_pin_cell() -> openmc.Model:
"""Create a PWR pin-cell model.
@ -51,7 +51,7 @@ def pwr_pin_cell() -> openmc.Model:
model.materials = (fuel, clad, hot_water)
# Instantiate ZCylinder surfaces
pitch = 1.26
pitch = PINCELL_PITCH
fuel_or = openmc.ZCylinder(x0=0, y0=0, r=0.39218, name='Fuel OR')
clad_or = openmc.ZCylinder(x0=0, y0=0, r=0.45720, name='Clad OR')
left = openmc.XPlane(x0=-pitch/2, name='left', boundary_type='reflective')
@ -319,14 +319,14 @@ def pwr_core() -> openmc.Model:
l100 = openmc.RectLattice(
name='Fuel assembly (lower half)', lattice_id=100)
l100.lower_left = (-10.71, -10.71)
l100.pitch = (1.26, 1.26)
l100.pitch = (PINCELL_PITCH, PINCELL_PITCH)
l100.universes = np.tile(fuel_cold, (17, 17))
l100.universes[tube_x, tube_y] = tube_cold
l101 = openmc.RectLattice(
name='Fuel assembly (upper half)', lattice_id=101)
l101.lower_left = (-10.71, -10.71)
l101.pitch = (1.26, 1.26)
l101.pitch = (PINCELL_PITCH, PINCELL_PITCH)
l101.universes = np.tile(fuel_hot, (17, 17))
l101.universes[tube_x, tube_y] = tube_hot
@ -350,7 +350,7 @@ def pwr_core() -> openmc.Model:
# Define core lattices
l200 = openmc.RectLattice(name='Core lattice (lower half)', lattice_id=200)
l200.lower_left = (-224.91, -224.91)
l200.pitch = (21.42, 21.42)
l200.pitch = (17 * PINCELL_PITCH, 17 * PINCELL_PITCH)
l200.universes = [
[fa_cw]*21,
[fa_cw]*21,
@ -376,7 +376,7 @@ def pwr_core() -> openmc.Model:
l201 = openmc.RectLattice(name='Core lattice (lower half)', lattice_id=201)
l201.lower_left = (-224.91, -224.91)
l201.pitch = (21.42, 21.42)
l201.pitch = (17 * PINCELL_PITCH, 17 * PINCELL_PITCH)
l201.universes = [
[fa_hw]*21,
[fa_hw]*21,
@ -488,7 +488,7 @@ def pwr_assembly() -> openmc.Model:
clad_or = openmc.ZCylinder(x0=0, y0=0, r=0.45720, name='Clad OR')
# Create boundary planes to surround the geometry
pitch = 21.42
pitch = 17 * PINCELL_PITCH
min_x = openmc.XPlane(x0=-pitch/2, boundary_type='reflective')
max_x = openmc.XPlane(x0=+pitch/2, boundary_type='reflective')
min_y = openmc.YPlane(y0=-pitch/2, boundary_type='reflective')
@ -514,7 +514,7 @@ def pwr_assembly() -> openmc.Model:
# Create fuel assembly Lattice
assembly = openmc.RectLattice(name='Fuel Assembly')
assembly.pitch = (pitch/17, pitch/17)
assembly.pitch = (PINCELL_PITCH, PINCELL_PITCH)
assembly.lower_left = (-pitch/2, -pitch/2)
# Create array indices for guide tube locations in lattice
@ -656,24 +656,21 @@ def slab_mg(num_regions=1, mat_names=None, mgxslib_name='2g.h5') -> openmc.Model
return model
def random_ray_lattice() -> openmc.Model:
"""Create a 2x2 PWR pincell asymmetrical lattic eexample.
This model is a 2x2 reflective lattice of fuel pins with one of the lattice
locations having just moderator instead of a fuel pin. It uses 7 group
cross section data.
def _generate_c5g7_materials() -> openmc.Materials:
"""Generate materials utilizing multi-group cross sections based on the
the C5G7 Benchmark.
Returns
-------
model : openmc.Model
A PWR 2x2 lattice model
materials : openmc.Materials
Materials object containing UO2 and water materials.
Data Sources
------------
All cross section data are from:
Lewis et al., "Benchmark specification for determinisitc 2D/3D MOX fuel
assembly transport calculations without spatial homogenization"
"""
model = openmc.Model()
###########################################################################
# Create MGXS data for the problem
# Instantiate the energy group data
group_edges = [1e-5, 0.0635, 10.0, 1.0e2, 1.0e3, 0.5e6, 1.0e6, 20.0e6]
groups = openmc.mgxs.EnergyGroups(group_edges)
@ -704,9 +701,10 @@ def random_ray_lattice() -> openmc.Model:
uo2_xsdata.set_fission([7.21206e-03, 8.19301e-04, 6.45320e-03,
1.85648e-02, 1.78084e-02, 8.30348e-02,
2.16004e-01])
uo2_xsdata.set_nu_fission([2.005998e-02, 2.027303e-03, 1.570599e-02,
4.518301e-02, 4.334208e-02, 2.020901e-01,
5.257105e-01])
nu_fission = np.array([2.005998e-02, 2.027303e-03, 1.570599e-02,
4.518301e-02, 4.334208e-02, 2.020901e-01,
5.257105e-01])
uo2_xsdata.set_nu_fission(nu_fission)
uo2_xsdata.set_chi([5.8791e-01, 4.1176e-01, 3.3906e-04, 1.1761e-07, 0.0000e+00,
0.0000e+00, 0.0000e+00])
@ -752,14 +750,28 @@ def random_ray_lattice() -> openmc.Model:
# Instantiate a Materials collection and export to XML
materials = openmc.Materials([uo2, water])
materials.cross_sections = "mgxs.h5"
return materials
###########################################################################
# Define problem geometry
def _generate_subdivided_pin_cell(uo2, water) -> openmc.Universe:
"""Create a radially and azimuthally subdivided pin cell universe. Helper
function for random_ray_pin_cell() and random_ray_lattice()
Parameters
----------
uo2 : openmc.Material
UO2 material
water : openmc.Material
Water material
Returns
-------
pincell : openmc.Universe
Universe containing an unbounded pin cell
"""
########################################
# Define an unbounded pincell universe
pitch = 1.26
# Define an unbounded pin cell universe
# Create a surface for the fuel outer radius
fuel_or = openmc.ZCylinder(r=0.54, name='Fuel OR')
@ -781,7 +793,7 @@ def random_ray_lattice() -> openmc.Model:
moderator_c = openmc.Cell(
fill=water, region=+outer_ring_b, name='moderator outer c')
# Create pincell universe
# Create pin cell universe
pincell_base = openmc.Universe()
# Register Cells with Universe
@ -801,19 +813,125 @@ def random_ray_lattice() -> openmc.Model:
for i in range(8):
azimuthal_cell = openmc.Cell(name=f'azimuthal_cell_{i}')
azimuthal_cell.fill = pincell_base
azimuthal_cell.region = +azimuthal_planes[i] & -azimuthal_planes[(i+1) % 8]
azimuthal_cell.region = + \
azimuthal_planes[i] & -azimuthal_planes[(i+1) % 8]
azimuthal_cells.append(azimuthal_cell)
# Create a geometry with the azimuthal universes
pincell = openmc.Universe(cells=azimuthal_cells, name='pincell')
return pincell
def random_ray_pin_cell() -> openmc.Model:
"""Create a PWR pin cell example using C5G7 cross section data.
cross section data.
Returns
-------
model : openmc.Model
A PWR pin cell model
"""
model = openmc.Model()
###########################################################################
# Create Materials for the problem
materials = _generate_c5g7_materials()
uo2 = materials[0]
water = materials[1]
###########################################################################
# Define problem geometry
pincell = _generate_subdivided_pin_cell(uo2, water)
########################################
# Define cell containing lattice and other stuff
pitch = PINCELL_PITCH
box = openmc.model.RectangularPrism(pitch, pitch, boundary_type='reflective')
pincell = openmc.Cell(fill=pincell, region=-box, name='pincell')
# Create a geometry with the top-level cell
geometry = openmc.Geometry([pincell])
###########################################################################
# Define problem settings
# Instantiate a Settings object, set all runtime parameters, and export to XML
settings = openmc.Settings()
settings.energy_mode = "multi-group"
settings.batches = 400
settings.inactive = 200
settings.particles = 100
# Create an initial uniform spatial source distribution over fissionable zones
lower_left = (-pitch / 2, -pitch / 2, -1)
upper_right = (pitch / 2, pitch / 2, 1)
uniform_dist = openmc.stats.Box(lower_left, upper_right)
rr_source = openmc.IndependentSource(space=uniform_dist)
settings.random_ray['distance_active'] = 100.0
settings.random_ray['distance_inactive'] = 20.0
settings.random_ray['ray_source'] = rr_source
settings.random_ray['volume_normalized_flux_tallies'] = True
###########################################################################
# Define tallies
# Now use the mesh filter in a tally and indicate what scores are desired
tally = openmc.Tally(name="Pin tally")
tally.scores = ['flux', 'fission', 'nu-fission']
tally.estimator = 'analog'
# Instantiate a Tallies collection and export to XML
tallies = openmc.Tallies([tally])
###########################################################################
# Exporting to OpenMC model
###########################################################################
model.geometry = geometry
model.materials = materials
model.settings = settings
model.tallies = tallies
return model
def random_ray_lattice() -> openmc.Model:
"""Create a 2x2 PWR pin cell asymmetrical lattice example.
This model is a 2x2 reflective lattice of fuel pins with one of the lattice
locations having just moderator instead of a fuel pin. It uses C5G7
cross section data.
Returns
-------
model : openmc.Model
A PWR 2x2 lattice model
"""
model = openmc.Model()
###########################################################################
# Create Materials for the problem
materials = _generate_c5g7_materials()
uo2 = materials[0]
water = materials[1]
###########################################################################
# Define problem geometry
pincell = _generate_subdivided_pin_cell(uo2, water)
########################################
# Define a moderator lattice universe
moderator_infinite = openmc.Cell(fill=water, name='moderator infinite')
moderator_infinite = openmc.Cell(name='moderator infinite')
moderator_infinite.fill = water
mu = openmc.Universe()
mu.add_cells([moderator_infinite])
pitch = PINCELL_PITCH
lattice = openmc.RectLattice()
lattice.lower_left = [-pitch/2.0, -pitch/2.0]
lattice.pitch = [pitch/10.0, pitch/10.0]
@ -837,8 +955,7 @@ def random_ray_lattice() -> openmc.Model:
########################################
# Define cell containing lattice and other stuff
box = openmc.model.RectangularPrism(
pitch*2, pitch*2, boundary_type='reflective')
box = openmc.model.RectangularPrism(pitch*2, pitch*2, boundary_type='reflective')
assembly = openmc.Cell(fill=lattice2x2, region=-box, name='assembly')