def pincell_model():
"""Set up a model to test with and delete files when done"""
openmc.reset_auto_ids()
pincell = openmc.examples.pwr_pin_cell()
pincell.settings.verbosity = 1
# Add a tally
filter1 = openmc.MaterialFilter(pincell.materials)
filter2 = openmc.EnergyFilter([0.0, 1.0, 1.0e3, 20.0e6])
mat_tally = openmc.Tally()
mat_tally.filters = [filter1, filter2]
mat_tally.nuclides = ['U235', 'U238']
mat_tally.scores = ['total', 'elastic', '(n,gamma)']
pincell.tallies.append(mat_tally)
# Add an expansion tally
zernike_tally = openmc.Tally()
filter3 = openmc.ZernikeFilter(5, r=.63)
cells = pincell.geometry.root_universe.cells
filter4 = openmc.CellFilter(list(cells.values()))
zernike_tally.filters = [filter3, filter4]
zernike_tally.scores = ['fission']
pincell.tallies.append(zernike_tally)
# Add an energy function tally
energyfunc_tally = openmc.Tally()
energyfunc_filter = openmc.EnergyFunctionFilter([0.0, 20e6], [0.0, 20e6])
energyfunc_tally.scores = ['fission']
energyfunc_tally.filters = [energyfunc_filter]
pincell.tallies.append(energyfunc_tally)
# Write XML files in tmpdir
with cdtemp():
pincell.export_to_xml()
yield
def pincell_model_w_univ():
"""Set up a model to test with and delete files when done"""
openmc.reset_auto_ids()
pincell = openmc.examples.pwr_pin_cell()
clad_univ = openmc.Universe(cells=[openmc.Cell(fill=pincell.materials[1])])
pincell.geometry.root_universe.cells[2].fill = clad_univ
pincell.settings.verbosity = 1
# Write XML files in tmpdir
with cdtemp():
pincell.export_to_xml()
yield
def dagmc_model(request):
model = openmc.model.Model()
# settings
model.settings.batches = 5
model.settings.inactive = 0
model.settings.particles = 100
model.settings.temperature = {'tolerance': 50.0}
model.settings.verbosity = 1
source_box = openmc.stats.Box([-4, -4, -4], [4, 4, 4])
source = openmc.Source(space=source_box)
model.settings.source = source
# geometry
dagmc_universe = openmc.DAGMCUniverse('dagmc.h5m')
model.geometry = openmc.Geometry(dagmc_universe)
# tally
tally = openmc.Tally()
tally.scores = ['total']
tally.filters = [openmc.CellFilter(1)]
model.tallies = [tally]
# materials
u235 = openmc.Material(name="no-void fuel")
u235.add_nuclide('U235', 1.0, 'ao')
u235.set_density('g/cc', 11)
u235.id = 40
u235.temperature = 320
water = openmc.Material(name="water")
water.add_nuclide('H1', 2.0, 'ao')
water.add_nuclide('O16', 1.0, 'ao')
water.set_density('g/cc', 1.0)
water.add_s_alpha_beta('c_H_in_H2O')
water.id = 41
mats = openmc.Materials([u235, water])
model.materials = mats
# location of dagmc file in test directory
dagmc_file = request.fspath.dirpath() + "/dagmc.h5m"
# move to a temporary directory
with cdtemp():
shutil.copyfile(dagmc_file, "./dagmc.h5m")
model.export_to_xml()
openmc.lib.init()
yield
openmc.lib.finalize()
def test_weightwindows(model):
ww_files = ('ww_n.txt', 'ww_p.txt')
cwd = Path(__file__).parent.absolute()
filepaths = [cwd / Path(f) for f in ww_files]
with cdtemp(filepaths):
# run once with variance reduction off
model.settings.weight_windows_on = False
analog_sp = model.run()
os.rename(analog_sp, 'statepoint.analog.h5')
# weight windows
# load pre-generated weight windows
# (created using the same tally as above)
ww_n_lower_bnds = np.loadtxt('ww_n.txt')
ww_p_lower_bnds = np.loadtxt('ww_p.txt')
# create a mesh matching the one used
# to generate the weight windows
ww_mesh = openmc.RegularMesh()
ww_mesh.lower_left = (-240, -240, -240)
ww_mesh.upper_right = (240, 240, 240)
ww_mesh.dimension = (5, 6, 7)
# energy bounds matching those of the
# generated weight windows
e_bnds = [0.0, 0.5, 2E7]
ww_n = openmc.WeightWindows(ww_mesh,
ww_n_lower_bnds,
None,
10.0,
e_bnds,
survival_ratio=1.01)
ww_p = openmc.WeightWindows(ww_mesh,
ww_p_lower_bnds,
None,
10.0,
e_bnds,
survival_ratio=1.01)
model.settings.weight_windows = [ww_n, ww_p]
# run again with variance reduction on
model.settings.weight_windows_on = True
ww_sp = model.run()
os.rename(ww_sp, 'statepoint.ww.h5')
# load both statepoints and examine results
asp = openmc.StatePoint('statepoint.analog.h5')
wsp = openmc.StatePoint('statepoint.ww.h5')
analog_tally = asp.tallies[1]
ww_tally = wsp.tallies[1]
def compare_results(particle, analog_tally, ww_tally):
# get values from each of the tallies
an_mean = analog_tally.get_values(filters=[openmc.ParticleFilter],
filter_bins=[(particle, )])
ww_mean = ww_tally.get_values(filters=[openmc.ParticleFilter],
filter_bins=[(particle, )])
# expect that more bins were scored with weight windows than
# the analog run
assert np.count_nonzero(an_mean) < np.count_nonzero(ww_mean)
an_rel_err = analog_tally.get_values(
filters=[openmc.ParticleFilter],
filter_bins=[(particle, )],
value='rel_err')
ww_rel_err = ww_tally.get_values(filters=[openmc.ParticleFilter],
filter_bins=[(particle, )],
value='rel_err')
an_rel_err[an_mean == 0.0] = 1.0
ww_rel_err[ww_mean == 0.0] = 1.0
an_avg_rel_err = np.mean(an_rel_err)
ww_avg_rel_err = np.mean(ww_rel_err)
# expect that the average relative error in the tally
# decreases
assert an_avg_rel_err > ww_avg_rel_err
# ensure that the value of the mesh bin containing the
# source is statistically similar in both runs
an_std_dev = analog_tally.get_values(
filters=[openmc.ParticleFilter],
filter_bins=[(particle, )],
value='std_dev')
ww_std_dev = ww_tally.get_values(filters=[openmc.ParticleFilter],
filter_bins=[(particle, )],
value='std_dev')
# index of the mesh bin containing the source for the higher
# energy group
source_bin_idx = (an_mean.shape[0] // 2, 0, 0)
an_source_bin = ufloat(an_mean[source_bin_idx],
an_std_dev[source_bin_idx])
ww_source_bin = ufloat(ww_mean[source_bin_idx],
ww_std_dev[source_bin_idx])
diff = an_source_bin - ww_source_bin
# check that values are within two combined standard deviations
assert abs(diff.nominal_value) / diff.std_dev < 2.0
compare_results('neutron', analog_tally, ww_tally)
compare_results('photon', analog_tally, ww_tally)