added IndependentOperator depletion example

tasks/task_14_activation_transmutation_depletion/3_full_pulse_schedule.py

@@ -0,0 +1,131 @@
+# This example performs a depletion simulation using the IndependentOperator
+# instead of the CoupledOperator used in the first examples.
+
+# This is an approximation so is less accurate but it is much faster.
+# This approach performs just a single transport simulation and obtains reactions rates once.
+# If the materials don't change significantly during the irradiation this is a reasonable approximation.
+# Fission fule pins would perhaps require the CoupledOperator while the majority of fusion simulations are suitable for the IndependentOperator
+
+# More details on both Operators in the docs
+# https://docs.openmc.org/en/stable/usersguide/depletion.html#transport-independent-depletion
+
+import openmc
+import openmc.deplete
+import math
+import matplotlib.pyplot as plt
+
+# chain and cross section paths have been set on the docker image but you may want to change them
+#openmc.config['chain_file']=/home/j/openmc_data/chain-endf-b8.0.xml
+#openmc.config['cross_sections']=/home/j/nndc-b8.0-hdf5/endfb-viii.0-hdf5/cross_sections.xml
+
+# Creates a simple material
+my_material = openmc.Material() 
+my_material.add_element('Ag', 1, percent_type='ao')
+my_material.set_density('g/cm3', 10.49)
+
+# As we are doing a depletion simulation we must set the material volume and the .depletion to True
+sphere_radius = 100
+volume_of_sphere = (4/3) * math.pi * math.pow(sphere_radius, 3)
+my_material.volume = volume_of_sphere  # a volume is needed so openmc can find the number of atoms in the cell/material
+my_material.depletable = True  # depletable = True is needed to tell openmc to update the material with each time step
+
+materials = openmc.Materials([my_material])
+
+# makes a simple sphere surface and cell
+sph1 = openmc.Sphere(r=sphere_radius, boundary_type='vacuum')
+shield_cell = openmc.Cell(region=-sph1)
+shield_cell.fill = my_material
+geometry = openmc.Geometry([shield_cell])
+
+# creates a simple point source
+source = openmc.IndependentSource()
+source.space = openmc.stats.Point((0, 0, 0))
+source.angle = openmc.stats.Isotropic()
+source.energy = openmc.stats.Discrete([14e6], [1])
+source.particles = 'neutron'
+
+settings = openmc.Settings()
+settings.batches = 10
+settings.inactive = 0
+settings.particles = 1000
+settings.source = source
+settings.run_mode = 'fixed source'
+
+model = openmc.model.Model(geometry, materials, settings)
+
+# this does perform transport but just to get the flux and micro xs
+flux_in_each_group, micro_xs = openmc.deplete.get_microxs_and_flux(
+    model=model,
+    domains=[shield_cell],
+    energies='CCFE-709',
+)
+
+# Plotting the neutron spectra
+plt.title('neutron flux spectra')
+plt.plot(openmc.mgxs.GROUP_STRUCTURES['CCFE-709'][:-1], flux_in_each_group[0])
+plt.xscale('log')
+plt.yscale('log')
+plt.show()
+
+# constructing the operator, note we pass in the flux and micro xs
+operator = openmc.deplete.IndependentOperator(
+    materials=materials,
+    fluxes=flux_in_each_group,
+    micros=micro_xs,
+    reduce_chain=True,  # reduced to only the isotopes present in depletable materials and their possible progeny
+    reduce_chain_level=5,
+    normalization_mode="source-rate"
+)
+
+# We define timesteps together with the source rate to make it clearer
+timesteps_and_source_rates = [
+    (24, 1e20),
+    (24, 1e20),
+    (24, 1e20),
+    (24, 1e20),
+    (24, 1e20),  # should saturate Ag110 here as it has been irradiated for over 5 halflives
+    (24, 1e20),
+    (24, 1e20),
+    (24, 1e20),
+    (24, 1e20),
+    (24, 0),
+    (24, 0),
+    (24, 0),
+    (24, 0),
+    (24, 0),
+    (24, 0),
+    (24, 0),
+    (24, 0),
+    (24, 0),
+    (24, 0),
+    (24, 0),
+]
+
+# Uses list Python comprehension to get the timesteps and source_rates separately
+timesteps = [item[0] for item in timesteps_and_source_rates]
+source_rates = [item[1] for item in timesteps_and_source_rates]
+
+# construct the integrator
+integrator = openmc.deplete.PredictorIntegrator(
+    operator=operator,
+    timesteps=timesteps,
+    source_rates=source_rates,
+    timestep_units='s'
+)
+
+# this runs the depltion calculations for the timesteps
+integrator.integrate()
+
+# Loads up the results
+results = openmc.deplete.ResultsList.from_hdf5("depletion_results.h5")
+times, number_of_Ag110_atoms = results.get_atoms(my_material, 'Ag110')
+
+# prints the atoms in a table
+for time, num in zip(times, number_of_Ag110_atoms):
+    print(f" Time {time}s. Number of Ag110 atoms {num}")
+
+# plots the number of atoms as a function of time
+plt.cla()
+plt.clf()
+plt.plot(times, number_of_Ag110_atoms)
+plt.show()