Merge pull request #256 from fusion-energy/adding_multipulse_fast_r2s

Adding multipulse fast r2s example using independent operator

tasks/task_11_CSG_shut_down_dose_tallies/2_faster_mulitiple_puse_shut_down_dose_rate_example.py

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+# This script simulates R2S method of shut down dose rate
+# on a simple sphere model.
+
+import numpy as np
+import openmc
+import openmc.deplete
+from pathlib import Path
+import math
+from matplotlib.colors import LogNorm
+
+# users might want to change these to use specific xml files to use particular decay data or transport cross sections
+# the chain file was downloaded with
+# pip install openmc_data
+# download_endf_chain -r b8.0
+# openmc.config['chain_file'] = '/nuclear_data/chain-endf-b8.0.xml'
+# openmc.config['cross_sections'] = 'cross_sections.xml'
+
+# a few user settings
+# Set up the folders to save all the data in
+n_particles = 1_00000
+p_particles = 1_000
+statepoints_folder = Path('statepoints_folder')
+
+# First we make a simple geometry with three cells, (two with material)
+sphere_surf_1 = openmc.Sphere(r=20, boundary_type="vacuum")
+sphere_surf_2 = openmc.Sphere(r=1, y0=10)
+sphere_surf_3 = openmc.Sphere(r=5, z0=10)
+
+sphere_region_1 = -sphere_surf_1 & +sphere_surf_2 & +sphere_surf_3  # void space
+sphere_region_2 = -sphere_surf_2
+sphere_region_3 = -sphere_surf_3
+
+sphere_cell_1 = openmc.Cell(region=sphere_region_1)
+sphere_cell_2 = openmc.Cell(region=sphere_region_2)
+sphere_cell_3 = openmc.Cell(region=sphere_region_3)
+
+# We make a iron material which should produce a few activation products
+mat_iron = openmc.Material()
+mat_iron.id = 1
+mat_iron.add_element("Fe", 1.0)
+mat_iron.set_density("g/cm3", 7.7)
+# must set the depletion to True to deplete the material
+mat_iron.depletable = True
+# volume must set the volume as well as openmc calculates number of atoms
+mat_iron.volume = (4 / 3) * math.pi * math.pow(sphere_surf_2.r, 3)
+sphere_cell_2.fill = mat_iron
+
+# We make a Al material which should produce a few different activation products
+mat_aluminum = openmc.Material()
+mat_aluminum.id = 2
+mat_aluminum.add_element("Al", 1.0)
+mat_aluminum.set_density("g/cm3", 2.7)
+# must set the depletion to True to deplete the material
+mat_aluminum.depletable = True
+# volume must set the volume as well as openmc calculates number of atoms
+mat_aluminum.volume = (4 / 3) * math.pi * math.pow(sphere_surf_3.r, 3)
+sphere_cell_3.fill = mat_aluminum
+
+my_geometry = openmc.Geometry([sphere_cell_1, sphere_cell_2, sphere_cell_3])
+
+my_materials = openmc.Materials([mat_iron, mat_aluminum])
+
+pristine_mat_iron = mat_iron.clone()
+pristine_mat_aluminium = mat_aluminum.clone()
+
+# gets the cell ids of any depleted cell
+activated_cell_ids = [c.id for c in my_geometry.get_all_material_cells().values() if c.fill.depletable]
+print("activated_cell_ids", activated_cell_ids)
+all_depletable_cells = [c for _, c in my_geometry.get_all_material_cells().items() if c.fill.depletable is True]
+print("depletable_cell_ids", activated_cell_ids)
+all_depletable_materials = [c.fill for _, c in my_geometry.get_all_material_cells().items() if c.fill.depletable is True]
+
+# 14MeV neutron source that activates material
+my_source = openmc.IndependentSource()
+my_source.space = openmc.stats.Point((0, 0, 0))
+my_source.angle = openmc.stats.Isotropic()
+my_source.energy = openmc.stats.Discrete([14.06e6], [1])
+my_source.particle = "neutron"
+
+# settings for the neutron simulation(s)
+my_neutron_settings = openmc.Settings()
+my_neutron_settings.run_mode = "fixed source"
+my_neutron_settings.particles = n_particles
+my_neutron_settings.batches = 10
+my_neutron_settings.source = my_source
+my_neutron_settings.photon_transport = False
+
+model_neutron = openmc.Model(my_geometry, my_materials, my_neutron_settings)
+
+hour_in_seconds = 60*60
+
+# This section defines the neutron pulse schedule.
+# If the method made use of the CoupledOperator then there would need to be a
+# transport simulation for each timestep. However as the IndependentOperator is
+# used then just a single transport simulation is done, thus speeding up the
+# simulation considerably.
+timesteps_and_source_rates = [
+    (1, 1e18),  # 1 second
+    (hour_in_seconds, 0),  # 1 hour
+    (1, 1e18),  # 1 second
+    (hour_in_seconds, 0),  # 2 hour
+    (1, 1e18),  # 1 second
+    (hour_in_seconds, 0),  # 3 hour
+    (1, 1e18),  # 1 second
+    (hour_in_seconds, 0),  # 4 hour
+    (1, 1e18),  # 1 second
+    (hour_in_seconds, 0),  # 4 hour
+    (1, 1e18),  # 1 second
+    (hour_in_seconds, 0),  # 4 hour
+    (1, 1e18),  # 1 second
+    (hour_in_seconds, 0),  # 5 hour
+]
+
+timesteps = [item[0] for item in timesteps_and_source_rates]
+source_rates = [item[1] for item in timesteps_and_source_rates]
+
+model_neutron.export_to_xml(directory=statepoints_folder/ "neutrons")
+
+# 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_neutron,
+    domains=all_depletable_cells,
+    energies='CCFE-709', # different group structures see this file for all the groups available https://github.com/openmc-dev/openmc/blob/develop/openmc/mgxs/__init__.py
+)
+
+# constructing the operator, note we pass in the flux and micro xs
+operator = openmc.deplete.IndependentOperator(
+    materials=openmc.Materials(all_depletable_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"
+)
+
+integrator = openmc.deplete.PredictorIntegrator(
+    operator=operator,
+    timesteps=timesteps,
+    source_rates=source_rates,
+    timestep_units='s'
+)
+
+# this runs the depletion calculations for the timesteps
+# this does the neutron activation simulations and produces a depletion_results.h5 file
+integrator.integrate(path=statepoints_folder / "neutrons" / "depletion_results.h5")
+# TODO add output dir to integrate command so we don't have to move the file like this
+# PR on openmc is open
+import os
+os.system(f'mv depletion_results.h5 {statepoints_folder / "neutrons" / "depletion_results.h5"}')
+
+# Now we have done the neutron activation simulations we can start the work needed for the decay gamma simulations.
+
+my_gamma_settings = openmc.Settings()
+my_gamma_settings.run_mode = "fixed source"
+my_gamma_settings.batches = 100
+my_gamma_settings.particles = p_particles
+
+
+# First we add make dose tally on a regular mesh
+
+
+# creates a regular mesh that surrounds the geometry
+mesh = openmc.RegularMesh().from_domain(
+    my_geometry,
+    dimension=[10, 10, 10],  # 10 voxels in each axis direction (x, y, z)
+)
+
+# adding a dose tally on a regular mesh
+# AP, PA, LLAT, RLAT, ROT, ISO are ICRP incident dose field directions, AP is front facing
+energies, pSv_cm2 = openmc.data.dose_coefficients(particle="photon", geometry="AP")
+dose_filter = openmc.EnergyFunctionFilter(
+    energies, pSv_cm2, interpolation="cubic"  # interpolation method recommended by ICRP
+)
+particle_filter = openmc.ParticleFilter(["photon"])
+mesh_filter = openmc.MeshFilter(mesh)
+flux_tally = openmc.Tally()
+flux_tally.filters = [mesh_filter, dose_filter, particle_filter]
+flux_tally.scores = ["flux"]
+flux_tally.name = "photon_dose_on_mesh"
+
+tallies = openmc.Tallies([flux_tally])
+
+cells = model_neutron.geometry.get_all_cells()
+activated_cells = [cells[uid] for uid in activated_cell_ids]
+
+# this section makes the photon sources from each active material at each
+# timestep and runs the photon simulations
+results = openmc.deplete.Results(statepoints_folder / "neutrons" / "depletion_results.h5")
+
+for i_cool in range(1, len(timesteps)):
+
+    # range starts at 1 to skip the first step as that is an irradiation step and there is no
+    # decay gamma source from the stable material at that time
+    # also there are no decay products in this first timestep for this model
+
+        photon_sources_for_timestep = []
+        print(f"making photon source for timestep {i_cool}")
+
+        all_activated_materials_in_timestep = []
+
+        for activated_cell_id in activated_cell_ids:
+            # gets the material id of the material filling the cell
+            material_id = cells[activated_cell_id].fill.id
+
+            # gets the activated material using the material id
+            activated_mat = results[i_cool].get_material(str(material_id))
+            # gets the energy and probabilities for the 
+            energy = activated_mat.get_decay_photon_energy(
+                clip_tolerance = 1e-6,  # cuts out a small fraction of the very low energy (and hence negligible dose contribution) photons
+                units = 'Bq',
+            )
+            strength = energy.integral()
+
+            if strength > 0.:  # only makes sources for 
+                space = openmc.stats.Box(*cells[activated_cell_id].bounding_box)
+                source = openmc.IndependentSource(
+                    space=space,
+                    energy=energy,
+                    particle="photon",
+                    strength=strength,
+                    domains=[cells[activated_cell_id]],
+                )
+                photon_sources_for_timestep.append(source)
+
+
+        my_gamma_settings.source = photon_sources_for_timestep
+
+
+        # one should also fill the cells with the activated material
+        # the activated material contains ALL the nuclides produced during activation
+        # sphere_cell_2.fill =  results[i_cool].get_material("1")
+        # sphere_cell_3.fill =  results[i_cool].get_material("2")
+        # my_geometry = openmc.Geometry([sphere_cell_1, sphere_cell_2, sphere_cell_3])
+
+        # however it is unlikely that they all appear in your transport cross_sections.xml
+        # so you could make use of openmc.deplete.Results.export_to_materials to export the modified activated material that
+        # just contains isotopes that appear in your cross_sections.xml
+
+        # however in this example we just use the original pristine material my_materials that were cloned earlier
+        # my_geometry is also the same as the neutron simulation
+        pristine_mat_iron.id = 1
+        pristine_mat_aluminium.id =2
+        my_materials = openmc.Materials([pristine_mat_iron, pristine_mat_aluminium])
+
+        model_gamma = openmc.Model(my_geometry, my_materials, my_gamma_settings, tallies)
+
+        model_gamma.run(cwd=statepoints_folder / "photons" / f"photon_at_time_{i_cool}")
+
+
+pico_to_micro = 1e-6
+seconds_to_hours = 60*60
+
+# You may wish to plot the dose tally on a mesh, this package makes it easy to include the geometry with the mesh tally
+from openmc_regular_mesh_plotter import plot_mesh_tally
+for i_cool in range(1, len(timesteps)):
+    with openmc.StatePoint(statepoints_folder / "photons" / f"photon_at_time_{i_cool}" / 'statepoint.100.h5') as statepoint:
+        photon_tally = statepoint.get_tally(name="photon_dose_on_mesh")
+
+        # normalising this tally is a little different to other examples as the source strength has been using units of photons per second.
+        # tally.mean is in units of pSv-cm3/source photon.
+        # as source strength is in photons_per_second this changes units to pSv-/second
+
+        # multiplication by pico_to_micro converts from (pico) pSv/s to (micro) uSv/s
+        # dividing by mesh voxel volume cancles out the cm3 units
+        # could do the mesh volume scaling on the plot and vtk functions but doing it here instead
+        scaling_factor = (seconds_to_hours * pico_to_micro) / mesh.volumes[0][0][0]
+
+        plot = plot_mesh_tally(
+                tally=photon_tally,
+                basis="xz",
+                # score='flux', # only one tally so can make use of default here
+                value="mean",
+                colorbar_kwargs={
+                    'label': "Decay photon dose [µSv/h]",
+                },
+                norm=LogNorm(),
+                volume_normalization=False,  # this is done in the scaling_factor
+                scaling_factor=scaling_factor,
+            )
+        plot.figure.savefig(f'shut_down_dose_map_timestep_{i_cool}')