Update depletion-related documentation

This commit is contained in:
Paul Romano 2020-02-12 16:05:58 -06:00
parent 4966ff7c5d
commit 4200b0dfbf
3 changed files with 67 additions and 122 deletions

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@ -33,12 +33,11 @@ material compositions over time. Each method appears as a different class.
For example, :class:`openmc.deplete.CECMIntegrator` runs a depletion calculation
using the CE/CM algorithm (deplete over a timestep using the middle-of-step
reaction rates). An instance of :class:`openmc.deplete.Operator` is passed to
one of these functions along with the power level and timesteps::
one of these functions along with the timesteps and power level::
power = 1200.0e6
days = 24*60*60
timesteps = [10.0*days, 10.0*days, 10.0*days]
openmc.deplete.CECMIntegrator(op, power, timesteps).integrate()
power = 1200.0e6 # watts
timesteps = [10.0, 10.0, 10.0] # days
openmc.deplete.CECMIntegrator(op, timesteps, power, timestep_units='d').integrate()
The coupled transport-depletion problem is executed, and once it is done a
``depletion_results.h5`` file is written. The results can be analyzed using the
@ -67,7 +66,7 @@ the energy deposited during a transport calculation will be lower than expected.
This causes the reaction rates to be over-adjusted to hit the user-specific power,
or power density, leading to an over-depletion of burnable materials.
There are some remedies. First, the fission Q values can be directly set in a
There are some remedies. First, the fission Q values can be directly set in a
variety of ways. This requires knowing what the total fission energy release should
be, including indirect components. Some examples are provided below::
@ -99,11 +98,11 @@ Local Spectra and Repeated Materials
------------------------------------
It is not uncommon to explicitly create a single burnable material across many locations.
From a pure transport perspective, there is nothing wrong with creating a single
From a pure transport perspective, there is nothing wrong with creating a single
3.5 wt.% enriched fuel ``fuel_3``, and placing that fuel in every fuel pin in an assembly
or even full core problem. This certainly expedites the model making process, but can pose
issues with depletion.
Under this setup, :mod:`openmc.deplete` will deplete a single ``fuel_3`` material using
issues with depletion.
Under this setup, :mod:`openmc.deplete` will deplete a single ``fuel_3`` material using
a single set of reaction rates, and produce a single new composition for the next time
step. This can be problematic if the same ``fuel_3`` is used in very different regions
of the problem.

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@ -1,25 +1,7 @@
import openmc
import openmc.deplete
import numpy as np
import matplotlib.pyplot as plt
###############################################################################
# Simulation Input File Parameters
###############################################################################
# OpenMC simulation parameters
batches = 100
inactive = 10
particles = 1000
# Depletion simulation parameters
time_step = 1*24*60*60 # s
final_time = 5*24*60*60 # s
time_steps = np.full(final_time // time_step, time_step)
chain_file = './chain_simple.xml'
power = 174 # W/cm, for 2D simulations only (use W for 3D)
###############################################################################
# Load previous simulation results
###############################################################################
@ -37,31 +19,34 @@ previous_results = openmc.deplete.ResultsList("depletion_results.h5")
###############################################################################
# Instantiate a Settings object, set all runtime parameters
settings_file = openmc.Settings()
settings_file.batches = batches
settings_file.inactive = inactive
settings_file.particles = particles
settings = openmc.Settings()
settings.batches = 100
settings.inactive = 10
settings.particles = 10000
# Create an initial uniform spatial source distribution over fissionable zones
bounds = [-0.62992, -0.62992, -1, 0.62992, 0.62992, 1]
uniform_dist = openmc.stats.Box(bounds[:3], bounds[3:], only_fissionable=True)
settings_file.source = openmc.source.Source(space=uniform_dist)
settings.source = openmc.source.Source(space=uniform_dist)
entropy_mesh = openmc.RegularMesh()
entropy_mesh.lower_left = [-0.39218, -0.39218, -1.e50]
entropy_mesh.upper_right = [0.39218, 0.39218, 1.e50]
entropy_mesh.dimension = [10, 10, 1]
settings_file.entropy_mesh = entropy_mesh
settings.entropy_mesh = entropy_mesh
###############################################################################
# Initialize and run depletion calculation
###############################################################################
op = openmc.deplete.Operator(geometry, settings_file, chain_file,
previous_results)
# Create depletion "operator"
chain_file = './chain_simple.xml'
op = openmc.deplete.Operator(geometry, settings, chain_file, previous_results)
# Perform simulation using the predictor algorithm
integrator = openmc.deplete.PredictorIntegrator(op, time_steps, power)
time_steps = [1.0, 1.0, 1.0, 1.0, 1.0] # days
power = 174 # W/cm, for 2D simulations only (use W for 3D)
integrator = openmc.deplete.PredictorIntegrator(op, time_steps, power, timestep_units='d')
integrator.integrate()
###############################################################################
@ -77,27 +62,28 @@ time, keff = results.get_eigenvalue()
# Obtain U235 concentration as a function of time
time, n_U235 = results.get_atoms('1', 'U235')
# Obtain Xe135 absorption as a function of time
time, Xe_gam = results.get_reaction_rate('1', 'Xe135', '(n,gamma)')
# Obtain Xe135 capture reaction rate as a function of time
time, Xe_capture = results.get_reaction_rate('1', 'Xe135', '(n,gamma)')
###############################################################################
# Generate plots
###############################################################################
days = 24*60*60
plt.figure()
plt.plot(time/(24*60*60), keff, label="K-effective")
plt.plot(time/days, keff, label="K-effective")
plt.xlabel("Time (days)")
plt.ylabel("Keff")
plt.show()
plt.figure()
plt.plot(time/(24*60*60), n_U235, label="U 235")
plt.plot(time/days, n_U235, label="U 235")
plt.xlabel("Time (days)")
plt.ylabel("n U5 (-)")
plt.show()
plt.figure()
plt.plot(time/(24*60*60), Xe_gam, label="Xe135 absorption")
plt.plot(time/days, Xe_capture, label="Xe135 capture")
plt.xlabel("Time (days)")
plt.ylabel("RR (-)")
plt.show()

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@ -1,47 +1,31 @@
from math import pi
import openmc
import openmc.deplete
import numpy as np
import matplotlib.pyplot as plt
###############################################################################
# Simulation Input File Parameters
###############################################################################
# OpenMC simulation parameters
batches = 100
inactive = 10
particles = 1000
# Depletion simulation parameters
time_step = 1*24*60*60 # s
final_time = 5*24*60*60 # s
time_steps = np.full(final_time // time_step, time_step)
chain_file = './chain_simple.xml'
power = 174 # W/cm, for 2D simulations only (use W for 3D)
###############################################################################
# Define materials
###############################################################################
# Instantiate some Materials and register the appropriate Nuclides
uo2 = openmc.Material(material_id=1, name='UO2 fuel at 2.4% wt enrichment')
uo2 = openmc.Material(name='UO2 fuel at 2.4% wt enrichment')
uo2.set_density('g/cm3', 10.29769)
uo2.add_element('U', 1., enrichment=2.4)
uo2.add_element('O', 2.)
uo2.depletable = True
helium = openmc.Material(material_id=2, name='Helium for gap')
helium = openmc.Material(name='Helium for gap')
helium.set_density('g/cm3', 0.001598)
helium.add_element('He', 2.4044e-4)
zircaloy = openmc.Material(material_id=3, name='Zircaloy 4')
zircaloy = openmc.Material(name='Zircaloy 4')
zircaloy.set_density('g/cm3', 6.55)
zircaloy.add_element('Sn', 0.014 , 'wo')
zircaloy.add_element('Sn', 0.014, 'wo')
zircaloy.add_element('Fe', 0.00165, 'wo')
zircaloy.add_element('Cr', 0.001 , 'wo')
zircaloy.add_element('Cr', 0.001, 'wo')
zircaloy.add_element('Zr', 0.98335, 'wo')
borated_water = openmc.Material(material_id=4, name='Borated water')
borated_water = openmc.Material(name='Borated water')
borated_water.set_density('g/cm3', 0.740582)
borated_water.add_element('B', 4.0e-5)
borated_water.add_element('H', 5.0e-2)
@ -52,87 +36,62 @@ borated_water.add_s_alpha_beta('c_H_in_H2O')
# Create geometry
###############################################################################
# Instantiate ZCylinder surfaces
fuel_or = openmc.ZCylinder(surface_id=1, x0=0, y0=0, r=0.39218, name='Fuel OR')
clad_ir = openmc.ZCylinder(surface_id=2, x0=0, y0=0, r=0.40005, name='Clad IR')
clad_or = openmc.ZCylinder(surface_id=3, x0=0, y0=0, r=0.45720, name='Clad OR')
left = openmc.XPlane(surface_id=4, x0=-0.62992, name='left')
right = openmc.XPlane(surface_id=5, x0=0.62992, name='right')
bottom = openmc.YPlane(surface_id=6, y0=-0.62992, name='bottom')
top = openmc.YPlane(surface_id=7, y0=0.62992, name='top')
# Define surfaces
pitch = 1.25984
fuel_or = openmc.ZCylinder(r=0.39218, name='Fuel OR')
clad_ir = openmc.ZCylinder(r=0.40005, name='Clad IR')
clad_or = openmc.ZCylinder(r=0.45720, name='Clad OR')
box = openmc.model.rectangular_prism(pitch, pitch, boundary_type='reflective')
left.boundary_type = 'reflective'
right.boundary_type = 'reflective'
top.boundary_type = 'reflective'
bottom.boundary_type = 'reflective'
# Define cells
fuel = openmc.Cell(fill=uo2, region=-fuel_or)
gap = openmc.Cell(fill=helium, region=+fuel_or & -clad_ir)
clad = openmc.Cell(fill=zircaloy, region=+clad_ir & -clad_or)
water = openmc.Cell(fill=borated_water, region=+clad_or & box)
# Instantiate Cells
fuel = openmc.Cell(cell_id=1, name='cell 1')
gap = openmc.Cell(cell_id=2, name='cell 2')
clad = openmc.Cell(cell_id=3, name='cell 3')
water = openmc.Cell(cell_id=4, name='cell 4')
# Use surface half-spaces to define regions
fuel.region = -fuel_or
gap.region = +fuel_or & -clad_ir
clad.region = +clad_ir & -clad_or
water.region = +clad_or & +left & -right & +bottom & -top
# Register Materials with Cells
fuel.fill = uo2
gap.fill = helium
clad.fill = zircaloy
water.fill = borated_water
# Instantiate Universe
root = openmc.Universe(universe_id=0, name='root universe')
# Register Cells with Universe
root.add_cells([fuel, gap, clad, water])
# Instantiate a Geometry, register the root Universe
geometry = openmc.Geometry(root)
# Define overall geometry
geometry = openmc.Geometry([fuel, gap, clad, water])
###############################################################################
# Set volumes of depletable materials
###############################################################################
# Compute cell areas
area = {}
area[fuel] = np.pi * fuel_or.coefficients['r'] ** 2
# Set materials volume for depletion. Set to an area for 2D simulations
uo2.volume = area[fuel]
# Set material volume for depletion. For 2D simulations, this should be an area.
uo2.volume = pi * fuel_or.r**2
###############################################################################
# Transport calculation settings
###############################################################################
# Instantiate a Settings object, set all runtime parameters, and export to XML
settings_file = openmc.Settings()
settings_file.batches = batches
settings_file.inactive = inactive
settings_file.particles = particles
settings = openmc.Settings()
settings.batches = 100
settings.inactive = 10
settings.particles = 1000
# Create an initial uniform spatial source distribution over fissionable zones
bounds = [-0.62992, -0.62992, -1, 0.62992, 0.62992, 1]
uniform_dist = openmc.stats.Box(bounds[:3], bounds[3:], only_fissionable=True)
settings_file.source = openmc.source.Source(space=uniform_dist)
settings.source = openmc.source.Source(space=uniform_dist)
entropy_mesh = openmc.RegularMesh()
entropy_mesh.lower_left = [-0.39218, -0.39218, -1.e50]
entropy_mesh.upper_right = [0.39218, 0.39218, 1.e50]
entropy_mesh.dimension = [10, 10, 1]
settings_file.entropy_mesh = entropy_mesh
settings.entropy_mesh = entropy_mesh
###############################################################################
# Initialize and run depletion calculation
###############################################################################
op = openmc.deplete.Operator(geometry, settings_file, chain_file)
# Create depletion "operator"
chain_file = './chain_simple.xml'
op = openmc.deplete.Operator(geometry, settings, chain_file)
# Perform simulation using the predictor algorithm
integrator = openmc.deplete.PredictorIntegrator(op, time_steps, power)
time_steps = [1.0, 1.0, 1.0, 1.0, 1.0] # days
power = 174 # W/cm, for 2D simulations only (use W for 3D)
integrator = openmc.deplete.PredictorIntegrator(op, time_steps, power, timestep_units='d')
integrator.integrate()
###############################################################################
@ -148,27 +107,28 @@ time, keff = results.get_eigenvalue()
# Obtain U235 concentration as a function of time
time, n_U235 = results.get_atoms('1', 'U235')
# Obtain Xe135 absorption as a function of time
time, Xe_gam = results.get_reaction_rate('1', 'Xe135', '(n,gamma)')
# Obtain Xe135 capture reaction rate as a function of time
time, Xe_capture = results.get_reaction_rate('1', 'Xe135', '(n,gamma)')
###############################################################################
# Generate plots
###############################################################################
days = 24*60*60
plt.figure()
plt.plot(time/(24*60*60), keff, label="K-effective")
plt.plot(time/days, keff, label="K-effective")
plt.xlabel("Time (days)")
plt.ylabel("Keff")
plt.show()
plt.figure()
plt.plot(time/(24*60*60), n_U235, label="U 235")
plt.plot(time/days, n_U235, label="U235")
plt.xlabel("Time (days)")
plt.ylabel("n U5 (-)")
plt.show()
plt.figure()
plt.plot(time/(24*60*60), Xe_gam, label="Xe135 absorption")
plt.plot(time/days, Xe_capture, label="Xe135 capture")
plt.xlabel("Time (days)")
plt.ylabel("RR (-)")
plt.show()