Adding 10k pebble OpenMC model and generation script.

10k_pebbles/README.md

+
+
+# Files
+
+## dat_to_csv.py
+
+Used to convert the initial data file for the pebble centers to a CSV format.
+
+## openmc_model.py
+
+Creates an OpenMC model using the pebble centers found in the pebble_centers.txt file.

10k_pebbles/dat_to_csv.py

+
+import numpy as np
+
+header_length = 8
+
+with open('11145_pebble_yuhsiang_E3p5M_peb.11k.dat', 'r') as fh:
+
+    for i in range(header_length):
+        fh.readline()
+
+    centers = np.fromfile(fh, sep=' ', dtype=float)
+
+centers = centers.reshape((centers.size // 3, 3))
+np.savetxt('centers.txt', centers)

10k_pebbles/materials.xml

+<?xml version='1.0' encoding='utf-8'?>
+<materials>
+  <material depletable="true" id="1" name="m_fuel - uranium oxycarbide - triso partciles">
+    <density units="g/cm3" value="10.5" />
+    <nuclide name="U234" wo="0.03565284" />
+    <nuclide name="U235" wo="17.790767159999998" />
+    <nuclide name="U238" wo="71.75358" />
+    <nuclide name="C0" wo="1.8" />
+    <nuclide name="O16" wo="8.616527990092724" />
+    <nuclide name="O17" wo="0.003472009907274255" />
+  </material>
+  <material id="2" name="m_graphite_c_buffer - triso partciles">
+    <density units="g/cm3" value="1.0" />
+    <nuclide ao="1.0" name="C0" />
+    <sab name="c_Graphite" />
+  </material>
+  <material id="3" name="m_graphite_pyc - triso particles">
+    <density units="g/cm3" value="1.87" />
+    <nuclide ao="1.0" name="C0" />
+    <sab name="c_Graphite" />
+  </material>
+  <material id="4" name="sic - triso partciles">
+    <density units="g/cm3" value="3.2" />
+    <nuclide ao="1.0" name="C0" />
+    <nuclide ao="0.9222968" name="Si28" />
+    <nuclide ao="0.0468316" name="Si29" />
+    <nuclide ao="0.0308716" name="Si30" />
+  </material>
+  <material id="5" name="m_graphite_matrix - triso particles">
+    <density units="g/cm3" value="1.6" />
+    <nuclide ao="1.0" name="C0" />
+    <sab name="c_Graphite" />
+  </material>
+  <material id="6" name="m_graphite_inner - pebble inner zone">
+    <density units="g/cm3" value="1.59368" />
+    <nuclide ao="1.0" name="C0" />
+    <sab name="c_Graphite" />
+  </material>
+  <material id="7" name="m_graphite_outer - pebble outer zone">
+    <density units="g/cm3" value="1.74" />
+    <nuclide ao="1.0" name="C0" />
+    <sab name="c_Graphite" />
+  </material>
+  <material id="8" name="m_flibe - 2LiF-BeF2">
+    <density units="kg/m3" value="1962.13354" />
+    <nuclide ao="1.9999" name="Li7" />
+    <nuclide ao="9.999999999998899e-05" name="Li6" />
+    <nuclide ao="1.0" name="Be9" />
+    <nuclide ao="4.0" name="F19" />
+  </material>
+</materials>

10k_pebbles/openmc_model.py

+import os
+import math
+import numpy as np
+import openmc
+import openmc.model
+import scipy.stats
+import pandas as pd
+from   math   import pi
+from   IPython.display import Image
+import matplotlib.pyplot as plt
+
+# -------------- Unit Conversions -----------
+mm                    = 0.1   # default cm
+μm                    = 1e-4  # default cm
+
+# -------------- Output Parameters -------
+voxel = False              # Set 1 to generate 3d voxel plots              and 0 for 2d ppm plots
+random_distribution = False              # Set 1 for TRISO particles random distribution and 0 for regular lattice
+verbose = False
+
+# -------------- Functions ------------------
+def density_flibe(p, t):
+    """
+    Returns FLiBe density at a pressure, p,
+    and temperature, t in units of kg/m3
+    """
+    # assumes the default value for drho_dp of 1.7324e-7
+    rho = -0.4884*t + 1.7324e-7*(p - 101325.0) + 2413.0 # kg/m3
+    return rho
+
+# -------------- Geometry Parameters --------
+# TRISO particle
+radius_fuel           = 400.0*μm/2     # UCBTH-14-002, Table 2-1
+thickness_c_buffer    = 100.0*μm       # UCBTH-14-002, Table 2-1
+thickness_pyc_inner   =  35.0*μm       # UCBTH-14-002, Table 2-1
+thickness_sic         =  35.0*μm       # UCBTH-14-002, Table 2-1
+thickness_pyc_outer   =  35.0*μm       # UCBTH-14-002, Table 2-1
+radius_c_buffer       = radius_fuel      + thickness_c_buffer
+radius_pyc_inner      = radius_c_buffer  + thickness_pyc_inner
+radius_sic            = radius_pyc_inner + thickness_sic
+radius_pyc_outer      = radius_sic       + thickness_pyc_outer
+packing_fraction      = 0.40           # UCBTH-14-002, Table 2-1
+if random_distribution == 0:
+    pitch_triso_lattice   = (radius_fuel+thickness_c_buffer+thickness_pyc_inner+thickness_sic+thickness_pyc_outer)*(4*pi/3/packing_fraction)**0.33333333333333333333333
+
+radius_pebble_inner   = 2.5/2                     # UCBTH-14-002, Table 2-1 (differs slightly from Cisneros, Table 5-2) ; scaled by TAMU experiment factor
+radius_pebble_outer   = 3.0/2                     # UCBTH-14-002, Table 2-1; Cisneros, Table 5-2                        ; scaled by TAMU experiment factor
+radius_pebble_central = radius_pebble_outer - 0.1 # UCBTH-14-002, Table 2-1; Cisneros, Table 5-2      ; scaled by TAMU experiment factor
+tolerance             = 0.00                      # Tolerance for pebbles universe filling
+radius_pebble_flibe   = radius_pebble_outer+tolerance
+
+# Pebble centers coordinates (x,y,z)
+print("Reading pseudo-random pebble centers from file pebble_centers.txt")
+pebble_centers = np.loadtxt('list_pebbles_1568.csv', delimiter=',', skiprows=1)[:, 1:]
+print("File pebble_centers.txt reading completed")
+
+# Vessel Dimensions
+vessel_x, vessel_y = (0.0, 0.0)
+vessel_z_min = np.min(pebble_centers[:, 2]) - radius_pebble_outer
+vessel_z_max = np.max(pebble_centers[:, 2]) + radius_pebble_outer
+vessel_radius = np.max(np.linalg.norm(pebble_centers[:, :-1], axis=1)) + radius_pebble_outer
+
+# Add additional moderation surrounding the pebble bed to reduce the
+# artificially high k-eff due to reflecting boundary conditions
+extra_thickness =  12.125  # cm
+vessel_z_min -= extra_thickness # bottom plane vessel ; scaled by TAMU experiment factor
+vessel_z_max += extra_thickness # top plane    vessel ; scaled by TAMU experiment factor
+vessel_radius += extra_thickness #                       scaled by TAMU experiment factor
+vessel_height = vessel_z_max - vessel_z_min
+
+# -------------- Printing Parameters ---------
+if verbose:
+    print ("GEOMETRY PARAMETERS")
+    print ("TRISO particles radius_fuel           [cm] = {}".format(radius_fuel))
+    print ("TRISO particles radius_c_buffer       [cm] = {}".format(radius_c_buffer))
+    print ("TRISO particles radius_pyc_inner      [cm] = {}".format(radius_pyc_inner))
+    print ("TRISO particles radius_sic            [cm] = {}".format(radius_sic))
+    print ("TRISO particles radius_pyc_outer      [cm] = {}".format(radius_pyc_outer))
+    print ("TRISO particles packing fraction           = {}".format(packing_fraction))
+    print ("TRISO lattice pitch {}".format(pitch_triso_lattice))
+    if random_distribution==0:
+       print ("TRISO particles regular lattice pitch_triso_lattice [cm] = {}".format(pitch_triso_lattice))
+    print ("Pebble radius_pebble_inner   [cm] = {}".format(radius_pebble_inner))
+    print ("Pebble radius_pebble_outer   [cm] = {}".format(radius_pebble_outer))
+    print ("Pebble radius_pebble_central [cm] = {}".format(radius_pebble_central))
+    print ("Pebble radius_pebble_flibe   [cm] = {}".format(radius_pebble_flibe))
+    print ("Vessel radius_vessel         [cm] = {}".format(radius_vessel))
+    print ("Vessel z1_vessel (min z)     [cm] = {}".format(z1_vessel))
+    print ("Vessel height_vessel         [cm] = {}".format(height_vessel))
+    print ("Pebbles centers [cm] :")
+    print (pebble_centers)
+
+# -------------- Materials Parameters --------
+# TRISO particle
+enrichment_uranium   = 0.199
+fraction_u234        = 2e-3                 # U234/(U234+U235) mass from Giacint facility fuel
+density_fuel         = ('g/cm3', 10.5)      # UCBTH-14-002, Table 2-1
+density_c_buffer     = ('g/cm3', 1.0)       # Cisneros    , Table 3-1
+density_pyc          = ('g/cm3', 1.87)      # Cisneros    , Table 3-1
+density_sic          = ('g/cm3', 3.2)       # Cisneros    , Table 3-1
+# Pebble Graphite
+density_graphite_inner = ('g/cm3', 1.59368) # Cisneros    , Table 3-1
+density_graphite_outer = ('g/cm3', 1.74)    # Cisneros    , Table 3-1
+# FLiBe coolant
+enrichment_li7       = 0.99995
+temperature_inlet    = 273.15 + 600.0       # UCBTH-14-002, Table 1-1
+temperature_outlet   = 273.15 + 700.0       # UCBTH-14-002, Table 1-1
+temperature_flibe    = (temperature_inlet+temperature_outlet)/2
+# --------------------------------------------------
+# NO PARAMETERS DEFINITION BEYOND THIS LINE
+
+
+# -------------- Materials Definition --------------
+# TRISO particle
+# Fuel from Nagley et al. Fabrication of Uranium Oxycarbide Kernels for HTR Fuel https://inldigitallibrary.inl.gov/sites/sti/sti/4886646.pdf Table 2
+m_fuel = openmc.Material(name='m_fuel - uranium oxycarbide - triso partciles')
+m_fuel.add_nuclide('U234', 89.58*   enrichment_uranium*   fraction_u234 , percent_type='wo')
+m_fuel.add_nuclide('U235', 89.58*   enrichment_uranium*(1-fraction_u234), percent_type='wo')
+m_fuel.add_nuclide('U238', 89.58*(1-enrichment_uranium)                 , percent_type='wo')
+m_fuel.add_nuclide('C0'   ,  1.80                                        , percent_type='wo')
+m_fuel.add_element('O'   ,  8.62                                        , percent_type='wo')
+m_fuel.set_density(*density_fuel)
+
+#
+m_graphite_c_buffer = openmc.Material(name='m_graphite_c_buffer - triso partciles')
+m_graphite_c_buffer.set_density(*density_c_buffer)
+m_graphite_c_buffer.add_nuclide('C0', 1.0)
+m_graphite_c_buffer.add_s_alpha_beta('c_Graphite')
+#
+m_graphite_pyc = openmc.Material(name='m_graphite_pyc - triso particles')
+m_graphite_pyc.set_density(*density_pyc)
+m_graphite_pyc.add_nuclide('C0', 1.0)
+m_graphite_pyc.add_s_alpha_beta('c_Graphite')
+#
+m_sic = openmc.Material(name='sic - triso partciles')
+m_sic.add_nuclide('C0' , 1.0)
+m_sic.add_element('Si', 1.0)
+m_sic.set_density(*density_sic)
+# TODO: Add SiC S(alpha, beta) ; ENDF/B-VIIIb4 has data for both Si and C in SiC
+#
+m_graphite_matrix = openmc.Material(name='m_graphite_matrix - triso particles')
+m_graphite_matrix.set_density('g/cm3', 1.6)
+m_graphite_matrix.add_nuclide('C0', 1.0)
+m_graphite_matrix.add_s_alpha_beta('c_Graphite')
+# TODO: Need real specifications for the carbon filler
+# Pebble
+m_graphite_inner = openmc.Material(name='m_graphite_inner - pebble inner zone')
+m_graphite_inner.set_density(*density_graphite_inner)
+m_graphite_inner.add_nuclide('C0', 1.0)
+m_graphite_inner.add_s_alpha_beta('c_Graphite')
+#
+m_graphite_outer = openmc.Material(name='m_graphite_outer - pebble outer zone')
+m_graphite_outer.set_density(*density_graphite_outer)
+m_graphite_outer.add_nuclide('C0', 1.0)
+m_graphite_outer.add_s_alpha_beta('c_Graphite')
+# FLiBe coolant - From Cisneros, appendix B, material 24
+m_flibe = openmc.Material(name='m_flibe - 2LiF-BeF2')
+m_flibe.set_density('kg/m3', density_flibe(101.325e3, temperature_flibe))
+m_flibe.add_nuclide('Li7', 2.0*     enrichment_li7)
+m_flibe.add_nuclide('Li6', 2.0*(1 - enrichment_li7))
+m_flibe.add_element('Be' , 1.0)
+m_flibe.add_element('F'  , 4.0)
+# TODO: FLiBe coolant - no S(alpha, beta) data available up to ENDF/B-VIIIb4
+
+
+# -------------- Geometry Definition --------------
+# TRISO particle universe
+s_fuel             = openmc.Sphere(r=radius_fuel)
+s_c_buffer         = openmc.Sphere(r=radius_c_buffer)
+s_pyc_inner        = openmc.Sphere(r=radius_pyc_inner)
+s_sic              = openmc.Sphere(r=radius_sic)
+s_pyc_outer        = openmc.Sphere(r=radius_pyc_outer)
+c_triso_fuel       = openmc.Cell(name='TRICO Fuel', fill=m_fuel, region=-s_fuel)
+c_triso_c_buffer   = openmc.Cell(name='TRISO Graphite Buffer', fill=m_graphite_c_buffer, region=+s_fuel & -s_c_buffer)
+c_triso_pyc_inner  = openmc.Cell(name='TRISO Pyrolitic Graphite Inner', fill=m_graphite_pyc, region=+s_c_buffer  & -s_pyc_inner)
+c_triso_sic        = openmc.Cell(name='TIRSO Silicone Carbide', fill=m_sic, region=+s_pyc_inner & -s_sic)
+c_triso_pyc_outer  = openmc.Cell(name='TRISO Pyrolitic Graphite Outer', fill=m_graphite_pyc, region=+s_sic & -s_pyc_outer)
+c_triso_matrix     = openmc.Cell(name='TRISO Graphite Matrix', fill=m_graphite_matrix, region=+s_pyc_outer)
+
+triso_cells = [c_triso_fuel, c_triso_c_buffer, c_triso_pyc_inner, c_triso_sic, c_triso_pyc_outer, c_triso_matrix]
+u_triso = openmc.Universe(cells=triso_cells)
+
+# Pebble Geometry
+s_pebble_inner = openmc.Sphere(r=radius_pebble_inner)
+s_pebble_central = openmc.Sphere(r=radius_pebble_central)
+s_pebble_outer = openmc.Sphere(r=radius_pebble_outer)
+c_pebble_inner = openmc.Cell(name='Pebble graphite inner region', fill=m_graphite_inner, region=-s_pebble_inner)
+c_pebble_central = openmc.Cell(name='Pebble central region (TRISOs)', region=+s_pebble_inner & -s_pebble_central)
+c_pebble_outer = openmc.Cell(name='Pebble graphite outer region', fill=m_graphite_outer, region=+s_pebble_central & -s_pebble_outer)
+c_pebble_flibe = openmc.Cell(name='Pebble exterior (FLiBe)', fill=m_flibe, region=+s_pebble_outer)
+
+# Fill c_pebble_central with TRISO particles
+if random_distribution==0:
+   # TRISO particles regular lattice using 'pitch_triso_lattice'
+    l_triso                    = openmc.RectLattice(name='Pebble TRISO Lattice')
+    l_triso.lower_left         = (-pitch_triso_lattice/2, -pitch_triso_lattice/2, -pitch_triso_lattice/2)
+    l_triso.pitch              = ( pitch_triso_lattice  ,  pitch_triso_lattice  ,  pitch_triso_lattice)
+    l_triso.outer              = u_triso
+    l_triso.universes          = np.tile(u_triso, (20, 20, 20))
+# TRISO particles random distribution using 'packing_fraction'
+else:
+    c_triso_pyc_outer_random   = openmc.Cell(name='c_triso_pyc_outer_random', fill=m_graphite_pyc, region=+s_sic)
+    u_triso_random             = openmc.Universe(cells=[c_triso_fuel, c_triso_c_buffer, c_triso_pyc_inner, c_triso_sic, c_triso_pyc_outer_random])
+    if not os.path.exists('triso_centers.npy'):
+        print("Writing random TRISO centers to file triso_centers.npy")
+        r_triso_random             = +s_pebble_inner & -s_pebble_central
+        spheres_random             = openmc.model.pack_spheres(radius=radius_pyc_outer, region=r_triso_random, pf=packing_fraction, initial_pf=0.15)
+        triso_random               = [openmc.model.TRISO(radius_pyc_outer, u_triso_random, i) for i in spheres_random]
+        centers = np.vstack([i.center for i in triso_random])
+        if verbose:
+            packing_fraction = len(triso_random)*radius_pyc_outer**3/(radius_pebble_central**3-radius_pebble_inner**3)
+            print("Calculated packing fraction of the TRISO particles random distribution = {}".format(packing_fraction))
+            np.save('triso_centers.npy', triso_random)
+        print("Reading random TRISO centers from file triso_centers.npy")
+        triso_random = np.load('triso_centers.npy')
+        lower_left, upper_right    = c_pebble_central.region.bounding_box
+        shape                      = (5, 5, 5)
+        pitch                      = (upper_right - lower_left)/shape
+        l_triso                    = openmc.model.create_triso_lattice(triso_random, lower_left, pitch, shape, m_graphite_matrix)
+        print("File triso_centers.npy reading completed")
+
+# Fil central pebble cell with the TRISO lattice
+c_pebble_central.fill   = l_triso
+
+pebble_cells = [c_pebble_inner, c_pebble_central, c_pebble_outer, c_pebble_flibe]
+u_pebble = openmc.Universe(cells=pebble_cells)
+
+# Vessel cell
+vessel_barrel = openmc.ZCylinder(x0=vessel_x, y0=vessel_y, r=vessel_radius, boundary_type='reflective')
+vessel_bottom = openmc.ZPlane(z0=vessel_z_min, boundary_type='reflective')
+vessel_top = openmc.ZPlane(z0=vessel_z_max, boundary_type='reflective')
+vessel_region = -vessel_barrel & +vessel_bottom & -vessel_top
+vessel_cell = openmc.Cell(name='Pebble Vessel', region = vessel_region)
+
+# Creating TRISOs for the pebbles to pack them into a lattice for efficiency
+cell_name = ['cell_pebble_' + str(i) for i in range (len(pebble_centers))]
+pebble_trisos = []
+for center, name in zip(pebble_centers, cell_name):
+    pebble_trisos.append(openmc.model.TRISO(radius_pebble_outer, u_pebble, center))
+    pebble_trisos[-1].name = name
+
+# Place pebbles into a lattice
+llc_vessel, urc_vessel = vessel_region.bounding_box
+l_pebble_shape = np.asarray((10, 10, 10))
+l_pebble_pitch = (urc_vessel - llc_vessel) / l_pebble_shape
+l_pebble = openmc.model.create_triso_lattice(pebble_trisos, llc_vessel, l_pebble_pitch, l_pebble_shape, m_flibe)
+
+# fill vessel with pebble lattice
+vessel_cell.fill = l_pebble
+
+geom = openmc.Geometry([vessel_cell])
+
+if verbose:
+    print ("Cell of the vessel:")
+    print (vessel_cell)
+
+# -------------- Settings --------------------
+settings           = openmc.Settings()
+settings.source    = openmc.Source(space=openmc.stats.Box(*vessel_cell.bounding_box, only_fissionable=True))
+settings.particles = 50000
+settings.inactive  = 50
+settings.batches   = 250
+settings.temperature = dict(default=573, method='interpolation', multipole=True, range=(300.0, 1500.0), tolerance=1000.0)
+# Fuel volume calculation
+volume_fuel                  = openmc.VolumeCalculation([m_fuel], 10000000, *c_pebble_central.bounding_box)
+settings.volume_calculations = [volume_fuel]
+
+model = openmc.model.Model(geometry=geom, settings=settings)
+model.export_to_xml()
+
+# -------------- Plots --------------
+# Plot parameters
+vessel_diameter = 2.0 * vessel_radius
+pebble_diameter = 2.0 * radius_pebble_outer
+
+m_colors = {m_fuel:              'brown',
+            m_graphite_c_buffer: 'LightSteelBlue',
+            m_graphite_pyc:      'blue',
+            m_sic:               'orange',
+            m_graphite_matrix:   'cyan',
+            m_graphite_inner:    'DeepSkyBlue',
+            m_graphite_outer:    'Navy',
+            m_flibe:             'yellow'}
+#
+plot1          = openmc.Plot()
+plot1.filename = 'plot1'
+plot1.width    = (vessel_diameter, vessel_diameter)
+plot1.basis    = 'xy'
+plot1.origin   = (0, 0, 0)
+plot1.pixels   = (1000, 1000)
+plot1.color_by = 'material'
+plot1.colors   = m_colors
+#
+plot2          = openmc.Plot()
+plot2.filename = 'plot2'
+plot2.width    = (vessel_diameter, vessel_diameter)
+plot2.basis    = 'xy'
+plot2.origin   = (0, 0, 1)
+plot2.pixels   = (1000, 1000)
+plot2.color_by = 'material'
+plot2.colors   = m_colors
+#
+plot3          = openmc.Plot()
+plot3.filename = 'plot3'
+plot3.width    = (vessel_diameter, vessel_diameter)
+plot3.basis    = 'xy'
+plot3.origin   = (0, 0, 1)
+plot3.pixels   = (1000, 1000)
+plot3.color_by = 'material'
+plot3.colors   = m_colors
+#
+plot4          = openmc.Plot()
+plot4.filename = 'plot4'
+plot_width   = max(vessel_diameter, vessel_height)
+plot4.width    = (plot_width, plot_width)
+plot4.basis    = 'xz'
+plot_zcenter = vessel_z_min + vessel_height/2.0
+plot4.origin   = (0, 0, plot_zcenter)
+plot4.pixels   = (1000, 1000)
+plot4.color_by = 'material'
+plot4.colors   = m_colors
+#
+plots          = openmc.Plots([plot1, plot2, plot3, plot4])
+if voxel==1:
+   plotv1 = openmc.Plot()
+   plotv1.filename = 'plotv1'
+   plotv1.width    = (pebble_diameter, pebble_diameter, pebble_diameter)
+   plotv1.origin   = (0, 0 ,0)
+   plotv1.pixels   = (300, 300, 300)
+   plotv1.color_by = 'material'
+   plotv1.colors   = m_colors
+   plotv1.type     = 'voxel'
+   plots.append(plotv1)
+
+plots.export_to_xml()

10k_pebbles/plots.xml

+<?xml version='1.0' encoding='utf-8'?>
+<plots>
+  <plot basis="xy" color_by="material" filename="plot1" id="1" type="slice">
+    <origin>0 0 0</origin>
+    <width>112.29461186082898 112.29461186082898</width>
+    <pixels>1000 1000</pixels>
+    <color id="1" rgb="165 42 42" />
+    <color id="2" rgb="176 196 222" />
+    <color id="3" rgb="0 0 255" />
+    <color id="4" rgb="255 165 0" />
+    <color id="5" rgb="0 255 255" />
+    <color id="6" rgb="0 191 255" />
+    <color id="7" rgb="0 0 128" />
+    <color id="8" rgb="255 255 0" />
+  </plot>
+  <plot basis="xy" color_by="material" filename="plot2" id="2" type="slice">
+    <origin>0 0 1</origin>
+    <width>112.29461186082898 112.29461186082898</width>
+    <pixels>1000 1000</pixels>
+    <color id="1" rgb="165 42 42" />
+    <color id="2" rgb="176 196 222" />
+    <color id="3" rgb="0 0 255" />
+    <color id="4" rgb="255 165 0" />
+    <color id="5" rgb="0 255 255" />
+    <color id="6" rgb="0 191 255" />
+    <color id="7" rgb="0 0 128" />
+    <color id="8" rgb="255 255 0" />
+  </plot>
+  <plot basis="xy" color_by="material" filename="plot3" id="3" type="slice">
+    <origin>0 0 1</origin>
+    <width>112.29461186082898 112.29461186082898</width>
+    <pixels>1000 1000</pixels>
+    <color id="1" rgb="165 42 42" />
+    <color id="2" rgb="176 196 222" />
+    <color id="3" rgb="0 0 255" />
+    <color id="4" rgb="255 165 0" />
+    <color id="5" rgb="0 255 255" />
+    <color id="6" rgb="0 191 255" />
+    <color id="7" rgb="0 0 128" />
+    <color id="8" rgb="255 255 0" />
+  </plot>
+  <plot basis="xz" color_by="material" filename="plot4" id="4" type="slice">
+    <origin>0 0 0.013685704999996773</origin>
+    <width>112.29461186082898 112.29461186082898</width>
+    <pixels>1000 1000</pixels>
+    <color id="1" rgb="165 42 42" />
+    <color id="2" rgb="176 196 222" />
+    <color id="3" rgb="0 0 255" />
+    <color id="4" rgb="255 165 0" />
+    <color id="5" rgb="0 255 255" />
+    <color id="6" rgb="0 191 255" />
+    <color id="7" rgb="0 0 128" />
+    <color id="8" rgb="255 255 0" />
+  </plot>
+</plots>

10k_pebbles/settings.xml

+<?xml version='1.0' encoding='utf-8'?>
+<settings>
+  <run_mode>eigenvalue</run_mode>
+  <particles>50000</particles>
+  <batches>250</batches>
+  <inactive>50</inactive>
+  <source strength="1.0">
+    <space type="fission">
+      <parameters>-56.14730593041449 -56.14730593041449 -25.15211374 56.14730593041449 56.14730593041449 25.179485149999998</parameters>
+    </space>
+  </source>
+  <temperature_default>573</temperature_default>
+  <temperature_method>interpolation</temperature_method>
+  <temperature_multipole>true</temperature_multipole>
+  <temperature_range>300.0 1500.0</temperature_range>
+  <temperature_tolerance>1000.0</temperature_tolerance>
+  <volume_calc>
+    <domain_type>material</domain_type>
+    <domain_ids>1</domain_ids>
+    <samples>10000000</samples>
+    <lower_left>-1.4 -1.4 -1.4</lower_left>
+    <upper_right>1.4 1.4 1.4</upper_right>
+  </volume_calc>
+  <material_cell_offsets>false</material_cell_offsets>
+</settings>