def test_cutoff_construction(nuclide_bundle):
u235 = nuclide_bundle.u235
u238 = nuclide_bundle.u238
pu239 = nuclide_bundle.pu239
# defaults
helper = FissionYieldCutoffHelper(nuclide_bundle, 1)
assert helper.constant_yields == {
"U238": u238.yield_data[5.0e5],
"Pu239": pu239.yield_data[5e5]}
assert helper.thermal_yields == {"U235": u235.yield_data[0.0253]}
assert helper.fast_yields == {"U235": u235.yield_data[5e5]}
# use 14 MeV yields
helper = FissionYieldCutoffHelper(nuclide_bundle, 1, fast_energy=14e6)
assert helper.constant_yields == {
"U238": u238.yield_data[5.0e5],
"Pu239": pu239.yield_data[5e5]}
assert helper.thermal_yields == {"U235": u235.yield_data[0.0253]}
assert helper.fast_yields == {"U235": u235.yield_data[14e6]}
# specify missing thermal yields -> use 0.0253
helper = FissionYieldCutoffHelper(nuclide_bundle, 1, thermal_energy=1)
assert helper.thermal_yields == {"U235": u235.yield_data[0.0253]}
assert helper.fast_yields == {"U235": u235.yield_data[5e5]}
# request missing fast yields -> use epithermal
helper = FissionYieldCutoffHelper(nuclide_bundle, 1, fast_energy=1e4)
assert helper.thermal_yields == {"U235": u235.yield_data[0.0253]}
assert helper.fast_yields == {"U235": u235.yield_data[5e5]}
# higher cutoff energy -> obtain fast and "faster" yields
helper = FissionYieldCutoffHelper(nuclide_bundle, 1, cutoff=1e6,
thermal_energy=5e5, fast_energy=14e6)
assert helper.constant_yields == {"U238": u238.yield_data[5e5]}
assert helper.thermal_yields == {
"U235": u235.yield_data[5e5], "Pu239": pu239.yield_data[5e5]}
assert helper.fast_yields == {
"U235": u235.yield_data[14e6], "Pu239": pu239.yield_data[2e6]}
# test super low and super high cutoff energies
helper = FissionYieldCutoffHelper(
nuclide_bundle, 1, thermal_energy=0.001, cutoff=0.002)
assert helper.fast_yields == {}
assert helper.thermal_yields == {}
assert helper.constant_yields == {
"U235": u235.yield_data[0.0253], "U238": u238.yield_data[5e5],
"Pu239": pu239.yield_data[5e5]}
helper = FissionYieldCutoffHelper(
nuclide_bundle, 1, cutoff=15e6, fast_energy=17e6)
assert helper.thermal_yields == {}
assert helper.fast_yields == {}
assert helper.constant_yields == {
"U235": u235.yield_data[14e6], "U238": u238.yield_data[5e5],
"Pu239": pu239.yield_data[2e6]}
def test_cutoff_helper(materials, nuclide_bundle, therm_frac):
helper = FissionYieldCutoffHelper(nuclide_bundle,
len(materials),
cutoff=1e6,
fast_energy=14e6)
helper.generate_tallies(materials, [0])
non_zero_nucs = [n.name for n in nuclide_bundle]
tally_nucs = helper.update_tally_nuclides(non_zero_nucs)
assert tally_nucs == ["Pu239", "U235"]
# Check tallies
fission_tally = helper._fission_rate_tally
assert fission_tally is not None
filters = fission_tally.filters
assert len(filters) == 2
assert isinstance(filters[0], lib.MaterialFilter)
assert len(filters[0].bins) == len(materials)
assert isinstance(filters[1], lib.EnergyFilter)
# lower, cutoff, and upper energy
assert len(filters[1].bins) == 3
# Emulate building tallies
# material x energy, tallied_nuclides, 3
tally_data = proxy_tally_data(fission_tally)
helper._fission_rate_tally = Mock()
helper_flux = 1e6
tally_data[0] = therm_frac * helper_flux
tally_data[1] = (1 - therm_frac) * helper_flux
helper._fission_rate_tally.mean = tally_data
helper.unpack()
# expected results of shape (n_mats, 2, n_tnucs)
expected_results = np.empty((1, 2, len(tally_nucs)))
expected_results[:, 0] = therm_frac
expected_results[:, 1] = 1 - therm_frac
assert helper.results == pytest.approx(expected_results)
actual_yields = helper.weighted_yields(0)
assert actual_yields["U238"] == nuclide_bundle.u238.yield_data[5e5]
for nuc in tally_nucs:
assert actual_yields[nuc] == (helper.thermal_yields[nuc] * therm_frac +
helper.fast_yields[nuc] *
(1 - therm_frac))
def test_cutoff_failure(key):
with pytest.raises(TypeError, match=key):
FissionYieldCutoffHelper(None, None, **{key: None})
with pytest.raises(ValueError, match=key):
FissionYieldCutoffHelper(None, None, **{key: -1})