diff --git a/.devcontainer/Dockerfile b/.devcontainer/Dockerfile
index 8a3715f7..8dcaa041 100644
--- a/.devcontainer/Dockerfile
+++ b/.devcontainer/Dockerfile
@@ -40,7 +40,8 @@ RUN cp tasks/task_07_CSG_cell_tally_spectra/2_example_neutron_spectra_on_cell.ip
 RUN cp tasks/task_07_CSG_cell_tally_spectra/4_example_photon_spectra.ipynb tasks/half-day-workshop/task_13_example_photon_spectra.ipynb
 RUN cp tasks/task_08_CSG_mesh_tally/1_example_2d_regular_mesh_tallies.ipynb tasks/half-day-workshop/task_14_example_2d_regular_mesh_tallies.ipynb
 RUN cp tasks/task_10_activation_transmutation_depletion/3_full_pulse_schedule.ipynb tasks/half-day-workshop/task_15_full_pulse_schedule.ipynb
-RUN cp tasks/optimal_design.ipynb tasks/half-day-workshop/task_16_optimal_design.ipynb 
+RUN cp tasks/task_17_design_tasks/1_optimal_design.ipynb tasks/half-day-workshop/task_16_optimal_design.ipynb 
+RUN cp tasks/task_17_design_tasks/1_optimal_design_with_hints.ipynb tasks/half-day-workshop/task_16_optimal_designs_with_hints.ipynb 
 
 WORKDIR /tasks
 
diff --git a/tasks/task_17_design_tasks/1_optimal_design.ipynb b/tasks/task_17_design_tasks/1_optimal_design.ipynb
new file mode 100644
index 00000000..f097b73b
--- /dev/null
+++ b/tasks/task_17_design_tasks/1_optimal_design.ipynb
@@ -0,0 +1,425 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "id": "72324188-e724-46bf-9a3c-f7f6501ccc73",
+   "metadata": {},
+   "source": [
+    "This activity allows you to put you neutronics knowledge to the test\n",
+    "\n",
+    "We are going to simulate a tokamak where you get to decide the materials.\n",
+    "\n",
+    "The goal is to:\n",
+    "\n",
+    "- maximize the Tritium Breeding Ratio\n",
+    "- minimize the heating on the center colum\n",
+    "- maximize the heat in the blanket\n",
+    "\n",
+    "I recommend plotting the cross sections before you make your choices.\n",
+    "\n",
+    "The [example](https://github.com/fusion-energy/neutronics-workshop/blob/main/tasks/task_01_cross_sections/3_material_xs_plot.ipynb) for plotting cross sections might be useful."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "7114fda7-b184-46d4-bbce-0d88206c573e",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "import openmc"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "6d951d32",
+   "metadata": {},
+   "source": [
+    "# Task 1 - enter the names of materials"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "fbff5883",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "# options for coolant\n",
+    "\n",
+    "water = openmc.Material(name='water')\n",
+    "water.add_element('H', 2)\n",
+    "water.add_element('O', 1)\n",
+    "water.set_density('g/cm3', 1)\n",
+    "\n",
+    "helium = openmc.Material(name='helium')\n",
+    "helium.add_element('He', 1)\n",
+    "helium.set_density('g/cm3', 0.0014)\n",
+    "\n",
+    "super_critical_co2 = openmc.Material(name='super critical co2')\n",
+    "super_critical_co2.add_element('C', 1)\n",
+    "super_critical_co2.add_element('O', 2)\n",
+    "super_critical_co2.set_density('g/cm3', 0.001)\n",
+    "\n",
+    "\n",
+    "# options for first wall\n",
+    "\n",
+    "tungsten = openmc.Material(name=# your code here)\n",
+    "tungsten.add_element('W', 1, percent_type='wo')\n",
+    "tungsten.set_density('g/cm3', 19.2)\n",
+    "\n",
+    "steel = openmc.Material(name=# your code here)\n",
+    "steel.add_element('Fe', 0.95, percent_type='wo')\n",
+    "steel.add_element('C', 0.95, percent_type='wo')\n",
+    "steel.set_density('g/cm3', 1)\n",
+    "\n",
+    "silicon_carbide = openmc.Material(name=# your code here)\n",
+    "silicon_carbide.add_element('Si', 1)\n",
+    "silicon_carbide.add_element('C', 1)\n",
+    "silicon_carbide.set_density('g/cm3', 3.21)\n",
+    "\n",
+    "zirconium = openmc.Material(name=# your code here)\n",
+    "zirconium.add_element('Zr', 1, percent_type='wo')\n",
+    "zirconium.set_density('g/cm3', 6.49)\n",
+    "\n",
+    "# options for reflector\n",
+    "\n",
+    "beryllium = openmc.Material(name='mat_reflector')\n",
+    "beryllium.add_element('Be', 1, percent_type='wo')\n",
+    "beryllium.set_density('g/cm3', 1.85)\n",
+    "\n",
+    "tungsten = openmc.Material(name='mat_reflector')\n",
+    "tungsten.add_element('W', 1, percent_type='wo')\n",
+    "tungsten.set_density('g/cm3', 19.2)\n",
+    "\n",
+    "graphite = openmc.Material(name='mat_reflector')\n",
+    "graphite.add_element('C', 1, percent_type='wo')\n",
+    "graphite.set_density('g/cm3', 2.2)\n",
+    "\n",
+    "# options for breeder\n",
+    "\n",
+    "# note you can change the enrichment\n",
+    "lithium_lead = openmc.Material(name=# your code here)\n",
+    "lithium_lead.add_element('Pb', 84.2, percent_type='ao')\n",
+    "lithium_lead.add_element('Li', 15.8, percent_type='ao', enrichment=90.0, enrichment_target='Li6', enrichment_type='ao')\n",
+    "lithium_lead.set_density('g/cm3', 9.5)\n",
+    "\n",
+    "# note you can change the enrichment\n",
+    "lithium_orthosilicate = openmc.Material(name=# your code here)\n",
+    "lithium_orthosilicate.add_element('Si', 4, percent_type='ao')\n",
+    "lithium_orthosilicate.add_element('O', 1, percent_type='ao')\n",
+    "lithium_orthosilicate.add_element('Li', 4, percent_type='ao', enrichment=50.0, enrichment_target='Li6', enrichment_type='ao')\n",
+    "lithium_orthosilicate.set_density('g/cm3', 2.2)\n",
+    "\n",
+    "# note you can change the enrichment\n",
+    "lithium_titanate = openmc.Material(name=# your code here)\n",
+    "lithium_titanate.add_element('O', 12, percent_type='ao')\n",
+    "lithium_titanate.add_element('Ti', 5, percent_type='ao')\n",
+    "lithium_titanate.add_element('Li', 4, percent_type='ao', enrichment=40.0, enrichment_target='Li6', enrichment_type='ao')\n",
+    "lithium_titanate.set_density('g/cm3', 2.4)\n",
+    "\n",
+    "# note you can change the enrichment\n",
+    "liquid_lithium = openmc.Material(name=# your code here)\n",
+    "liquid_lithium.add_element('Li', 1, percent_type='ao', enrichment=7.0, enrichment_target='Li6', enrichment_type='ao')\n",
+    "liquid_lithium.set_density('g/cm3', 0.5)\n",
+    "\n",
+    "# conductor material\n",
+    "\n",
+    "mat_conductor = openmc.Material(name='mat_conductor')\n",
+    "mat_conductor.add_element('Nb', 1, percent_type='ao')\n",
+    "mat_conductor.add_element('Sn', 3, percent_type='ao')\n",
+    "mat_conductor.set_density('g/cm3', 8.96)\n",
+    "\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "09802e51",
+   "metadata": {},
+   "source": [
+    "# Task 2 - plot the tritium production cross sections of all the breeder options "
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "7f1a5eed",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "# your code goes here"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "72adc5fd",
+   "metadata": {},
+   "source": [
+    "# Task 3 - plot the absorption of all the coolants and first wall options"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "2df73f5b",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "# your code goes here"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "d363f4ab",
+   "metadata": {},
+   "source": [
+    "# Task 4 - select your materials"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "a2c3facd",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "# put in your chosen material option\n",
+    "my_materials = openmc.Materials([mat_conductor, # your code here])"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "a06692a5",
+   "metadata": {},
+   "source": [
+    "# Task 3 - Fill the cells with the materials"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "ef814191-35a3-44a9-b088-f27c1bb53457",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "\n",
+    "\n",
+    "# surfaces\n",
+    "central_column_surface_outer = openmc.ZCylinder(r=100)\n",
+    "central_column_surface_mid = openmc.ZCylinder(r=95)\n",
+    "central_column_surface_inner = openmc.ZCylinder(r=90)\n",
+    "\n",
+    "inner_sphere_surface = openmc.Sphere(r=495)\n",
+    "middle_sphere_surface = openmc.Sphere(r=500) \n",
+    "outer_sphere_surface = openmc.Sphere(r=505)\n",
+    "outer_outer_sphere_surface = openmc.Sphere(r=600)\n",
+    "edge_of_simulation_surface = openmc.Sphere(r=700, boundary_type='vacuum')\n",
+    "\n",
+    "# regions\n",
+    "central_column_region = -central_column_surface_inner & -edge_of_simulation_surface\n",
+    "central_column_coolant_region = +central_column_surface_inner & -central_column_surface_mid & -edge_of_simulation_surface\n",
+    "central_column_fw_region = +central_column_surface_mid & -central_column_surface_outer & -edge_of_simulation_surface\n",
+    "\n",
+    "inner_vessel_region = +central_column_surface_outer & -inner_sphere_surface\n",
+    "\n",
+    "blanket_fw_region = -middle_sphere_surface & +inner_sphere_surface & +central_column_surface_outer\n",
+    "blanket_coolant_region = +middle_sphere_surface & -outer_sphere_surface & +central_column_surface_outer\n",
+    "blanket_breeder_region = +outer_sphere_surface & -outer_outer_sphere_surface & +central_column_surface_outer\n",
+    "blanket_reflector_region = +outer_outer_sphere_surface & -edge_of_simulation_surface & +central_column_surface_outer\n",
+    "\n",
+    "# cells\n",
+    "central_column_cell = openmc.Cell(region=central_column_region, fill=mat_conductor)\n",
+    "central_column_coolant_cell = openmc.Cell(region=central_column_coolant_region, fill=# your code here)\n",
+    "central_column_fw_cell = openmc.Cell(region=central_column_fw_region, fill=# your code here)\n",
+    "inner_vessel_cell = openmc.Cell(region=inner_vessel_region)\n",
+    "blanket_fw_cell = openmc.Cell(region=blanket_fw_region, fill=# your code here)\n",
+    "blanket_coolant_cell = openmc.Cell(region=blanket_coolant_region, fill=# your code here)\n",
+    "blanket_breeder_cell  = openmc.Cell(region=blanket_breeder_region, fill=# your code here)\n",
+    "blanket_reflector_cell = openmc.Cell(region=blanket_reflector_region, fill=# your code here)\n",
+    "\n",
+    "my_geometry = openmc.Geometry([\n",
+    "    central_column_cell,\n",
+    "    central_column_coolant_cell,\n",
+    "    central_column_fw_cell,\n",
+    "    inner_vessel_cell,\n",
+    "    blanket_fw_cell,\n",
+    "    blanket_coolant_cell,\n",
+    "    blanket_breeder_cell,\n",
+    "    blanket_reflector_cell,\n",
+    "])\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "f4b45781",
+   "metadata": {},
+   "source": [
+    "# task 4 - plot the geometry"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "25c8dcf1",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "\n",
+    "# your code here\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "378674b3",
+   "metadata": {},
+   "source": [
+    "# Task 5 - plot the source location and energy"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "5ddd3c0a",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "# initialises a new source object\n",
+    "my_source = openmc.IndependentSource()\n",
+    "# the distribution of radius is just a single value\n",
+    "radius = openmc.stats.Discrete([300], [1])\n",
+    "# the distribution of source z values is just a single value\n",
+    "z_values = openmc.stats.Discrete([0], [1])\n",
+    "# the distribution of source azimuthal angles values is a uniform distribution between 0 and 2 Pi\n",
+    "angle = openmc.stats.Uniform(a=0., b=2* 3.14159265359)\n",
+    "# this makes the ring source using the three distributions and a radius\n",
+    "my_source.space = openmc.stats.CylindricalIndependent(r=radius, phi=angle, z=z_values, origin=(0.0, 0.0, 0.0))\n",
+    "# sets the direction to isotropic\n",
+    "my_source.angle = openmc.stats.Isotropic()\n",
+    "# sets the energy distribution to a Muir distribution neutrons\n",
+    "my_source.energy = openmc.stats.muir(e0=14080000.0, m_rat=5.0, kt=20000.0)\n",
+    "\n",
+    "my_settings = openmc.Settings()\n",
+    "my_settings.batches = 10\n",
+    "my_settings.inactive = 0\n",
+    "my_settings.particles = 500\n",
+    "my_settings.run_mode = 'fixed source'\n",
+    "my_settings.source = my_source\n",
+    "\n",
+    "# plot the source term\n",
+    "# your code goes here"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "d539543f",
+   "metadata": {},
+   "source": [
+    "# Task 7 - complete the tally scores and filters"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "0093ded0",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "cell_filter_breeder = openmc.CellFilter(blanket_breeder_cell)\n",
+    "tbr_tally = openmc.Tally(name='TBR')\n",
+    "tbr_tally.filters = [cell_filter_breeder]\n",
+    "tbr_tally.scores = [# your code here]\n",
+    "\n",
+    "cell_filter_blanket_fw_coolant = openmc.CellFilter([\n",
+    "    blanket_breeder_cell,\n",
+    "    blanket_coolant_cell,\n",
+    "    blanket_fw_cell,\n",
+    "    central_column_coolant_cell,\n",
+    "    central_column_fw_cell,\n",
+    "])\n",
+    "blanket_heating_tally = openmc.Tally(name='heating')\n",
+    "blanket_heating_tally.filters = [cell_filter_blanket_fw_coolant]\n",
+    "blanket_heating_tally.scores = ['heating']\n",
+    "\n",
+    "material_filter_conductor = openmc.MaterialFilter(# your code here)\n",
+    "conductor_damage_tally = openmc.Tally(name='conductor_damage')\n",
+    "conductor_damage_tally.filters = [material_filter_conductor]\n",
+    "conductor_damage_tally.scores = [# your code here]\n",
+    "\n",
+    "my_tallies = openmc.Tallies([tbr_tally, blanket_heating_tally, conductor_damage_tally])"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "84caa13e",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "model = openmc.model.Model(my_geometry, my_materials, my_settings, my_tallies)\n",
+    "\n",
+    "# removes the old output files\n",
+    "!rm *.h5 *.xml\n",
+    "\n",
+    "sp_filename = model.run()"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "f58aa313",
+   "metadata": {},
+   "source": [
+    "# Task 8 - complete the code to get the correct tally names"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "26ebca7b",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "sp = openmc.StatePoint(sp_filename)\n",
+    "\n",
+    "tbr_tally = sp.get_tally(name=# Your code here)\n",
+    "\n",
+    "print(f'TBR={tbr_tally.mean.flatten()[0]} with standard deviation of {tbr_tally.std_dev.flatten()[0]}')\n",
+    "\n",
+    "heating_tally = sp.get_tally(name=# Your code here)\n",
+    "print(f'Heating={heating_tally.mean.flatten()[0]/1e6}MeV per source neutron with standard deviation of {heating_tally.std_dev.flatten()[0]}')\n",
+    "\n",
+    "damage_tally = sp.get_tally(name=# Your code here)\n",
+    "print(f'damage={damage_tally.mean.flatten()[0]} with standard deviation of {damage_tally.std_dev.flatten()[0]}')\n",
+    "\n"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "8a48c3af",
+   "metadata": {},
+   "outputs": [],
+   "source": []
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 3 (ipykernel)",
+   "language": "python",
+   "name": "python3"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 3
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython3",
+   "version": "3.8.16"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 5
+}
diff --git a/tasks/optimal_design.ipynb b/tasks/task_17_design_tasks/1_optimal_design_with_hints.ipynb
similarity index 86%
rename from tasks/optimal_design.ipynb
rename to tasks/task_17_design_tasks/1_optimal_design_with_hints.ipynb
index c19f8799..49a189a5 100644
--- a/tasks/optimal_design.ipynb
+++ b/tasks/task_17_design_tasks/1_optimal_design_with_hints.ipynb
@@ -39,16 +39,16 @@
    "source": [
     "# options for coolant\n",
     "\n",
-    "water = openmc.Material(name='mat_coolant')\n",
+    "water = openmc.Material(name='water')\n",
     "water.add_element('H', 2)\n",
     "water.add_element('O', 1)\n",
     "water.set_density('g/cm3', 1)\n",
     "\n",
-    "helium = openmc.Material(name='mat_coolant')\n",
+    "helium = openmc.Material(name='helium')\n",
     "helium.add_element('He', 1)\n",
     "helium.set_density('g/cm3', 0.0014)\n",
     "\n",
-    "super_critical_co2 = openmc.Material(name='mat_coolant')\n",
+    "super_critical_co2 = openmc.Material(name='super critical co2')\n",
     "super_critical_co2.add_element('C', 1)\n",
     "super_critical_co2.add_element('O', 2)\n",
     "super_critical_co2.set_density('g/cm3', 0.001)\n",
@@ -56,62 +56,62 @@
     "\n",
     "# options for first wall\n",
     "\n",
-    "tungsten = openmc.Material(name='mat_reflector')\n",
+    "tungsten = openmc.Material(name='tungsten')\n",
     "tungsten.add_element('W', 1, percent_type='wo')\n",
     "tungsten.set_density('g/cm3', 19.2)\n",
     "\n",
-    "steel = openmc.Material(name='mat_firstwall')\n",
+    "steel = openmc.Material(name='steel')\n",
     "steel.add_element('Fe', 0.95, percent_type='wo')\n",
     "steel.add_element('C', 0.95, percent_type='wo')\n",
     "steel.set_density('g/cm3', 1)\n",
     "\n",
-    "silicon_carbide = openmc.Material(name='mat_firstwall')\n",
+    "silicon_carbide = openmc.Material(name='silicon_carbide')\n",
     "silicon_carbide.add_element('Si', 1)\n",
     "silicon_carbide.add_element('C', 1)\n",
     "silicon_carbide.set_density('g/cm3', 3.21)\n",
     "\n",
-    "zirconium = openmc.Material(name='mat_firstwall')\n",
+    "zirconium = openmc.Material(name='zirconium')\n",
     "zirconium.add_element('Zr', 1, percent_type='wo')\n",
     "zirconium.set_density('g/cm3', 6.49)\n",
     "\n",
     "# options for reflector\n",
     "\n",
-    "beryllium = openmc.Material(name='mat_reflector')\n",
+    "beryllium = openmc.Material(name='beryllium')\n",
     "beryllium.add_element('Be', 1, percent_type='wo')\n",
     "beryllium.set_density('g/cm3', 1.85)\n",
     "\n",
-    "tungsten = openmc.Material(name='mat_reflector')\n",
+    "tungsten = openmc.Material(name='tungsten')\n",
     "tungsten.add_element('W', 1, percent_type='wo')\n",
     "tungsten.set_density('g/cm3', 19.2)\n",
     "\n",
-    "graphite = openmc.Material(name='mat_reflector')\n",
+    "graphite = openmc.Material(name='graphite')\n",
     "graphite.add_element('C', 1, percent_type='wo')\n",
     "graphite.set_density('g/cm3', 2.2)\n",
     "\n",
     "# options for breeder\n",
     "\n",
     "# note you can change the enrichment\n",
-    "lithium_lead = openmc.Material(name='mat_breeder')\n",
+    "lithium_lead = openmc.Material(name='lithium_lead')\n",
     "lithium_lead.add_element('Pb', 84.2, percent_type='ao')\n",
     "lithium_lead.add_element('Li', 15.8, percent_type='ao', enrichment=90.0, enrichment_target='Li6', enrichment_type='ao')\n",
     "lithium_lead.set_density('g/cm3', 9.5)\n",
     "\n",
     "# note you can change the enrichment\n",
-    "lithium_orthosilicate = openmc.Material(name='mat_breeder')\n",
+    "lithium_orthosilicate = openmc.Material(name='lithium_orthosilicate')\n",
     "lithium_orthosilicate.add_element('Si', 4, percent_type='ao')\n",
     "lithium_orthosilicate.add_element('O', 1, percent_type='ao')\n",
     "lithium_orthosilicate.add_element('Li', 4, percent_type='ao', enrichment=50.0, enrichment_target='Li6', enrichment_type='ao')\n",
     "lithium_orthosilicate.set_density('g/cm3', 2.2)\n",
     "\n",
     "# note you can change the enrichment\n",
-    "lithium_titanate = openmc.Material(name='mat_breeder')\n",
+    "lithium_titanate = openmc.Material(name='lithium_titanate')\n",
     "lithium_titanate.add_element('O', 12, percent_type='ao')\n",
     "lithium_titanate.add_element('Ti', 5, percent_type='ao')\n",
     "lithium_titanate.add_element('Li', 4, percent_type='ao', enrichment=40.0, enrichment_target='Li6', enrichment_type='ao')\n",
     "lithium_titanate.set_density('g/cm3', 2.4)\n",
     "\n",
     "# note you can change the enrichment\n",
-    "liquid_lithium = openmc.Material(name='mat_breeder')\n",
+    "liquid_lithium = openmc.Material(name='liquid_lithium')\n",
     "liquid_lithium.add_element('Li', 1, percent_type='ao', enrichment=7.0, enrichment_target='Li6', enrichment_type='ao')\n",
     "liquid_lithium.set_density('g/cm3', 0.5)\n"
    ]
@@ -131,7 +131,19 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "# your code goes here"
+    "import matplotlib.pyplot as plt\n",
+    "\n",
+    "openmc.plotter.plot_xs(\n",
+    "    reactions = {\n",
+    "        lithium_lead: ['(n,Xt)'],\n",
+    "        lithium_orthosilicate: ['(n,Xt)'],\n",
+    "        lithium_orthosilicate: ['(n,Xt)'],\n",
+    "        lithium_titanate: ['(n,Xt)'],\n",
+    "        liquid_lithium: ['(n,Xt)'],\n",
+    "    }\n",
+    ")\n",
+    "plt.title = '(n,XT) cross section'\n",
+    "plt.savefig('tritium_cross_section_pushers.png', dpi=400)"
    ]
   },
   {
@@ -149,7 +161,19 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "# your code goes here"
+    "# your code goes hereimport matplotlib.pyplot as plt\n",
+    "\n",
+    "openmc.plotter.plot_xs(\n",
+    "    reactions = {\n",
+    "        lithium_lead: ['absorption'],\n",
+    "        lithium_orthosilicate: ['absorption'],\n",
+    "        lithium_orthosilicate: ['absorption'],\n",
+    "        lithium_titanate: ['absorption'],\n",
+    "        liquid_lithium: ['absorption'],\n",
+    "    }\n",
+    ")\n",
+    "plt.title = 'absorption cross section'\n",
+    "plt.savefig('absorption_cross_section_pushers.png', dpi=400)"
    ]
   },
   {
@@ -159,10 +183,10 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "mat_breeder = # your choice of material goes here\n",
-    "mat_coolant = # your choice of material goes here\n",
-    "mat_firstwall = # your choice of material goes here\n",
-    "mat_reflector = # your choice of material goes here"
+    "mat_breeder = liquid_lithium\n",
+    "mat_coolant = water\n",
+    "mat_firstwall = zirconium\n",
+    "mat_reflector = tungsten"
    ]
   },
   {