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Some fixes for JEFF 3.2 data (most notably supporting energy-dependent delayed

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neutron group probabilities)
This commit is contained in:
Paul Romano 2016-07-19 12:02:07 -05:00
parent 202bdfab3d
commit 5647db18b6
4 changed files with 41 additions and 4 deletions
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6
.gitignore vendored
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@ -60,8 +60,14 @@ src/install_manifest.txt
# Nuclear data
data/nndc
data/nndc_hdf5
data/wmp
data/multipole_lib.tar.gz
data/ENDF-B-VII.1-*.tar.gz
data/JEFF32-ACE-*.tar.gz
data/TSLs.tar.gz
data/jeff-3.2
data/jeff-3.2-hdf5
# Images
*.ppm

3
openmc/data/correlated.py
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@ -359,6 +359,9 @@ class CorrelatedAngleEnergy(AngleEnergy):
INTERPOLATION_SCHEME[intt],
ignore_negative=True)
eout_continuous.c = data[2][n_discrete_lines:]
if np.any(data[1][n_discrete_lines:] < 0.0):
warn("Correlated angle-energy distribution has negative "
"probabilities.")
# If discrete lines are present, create a mixture distribution
if n_discrete_lines > 0:

6
openmc/data/kalbach_mann.py
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@ -320,8 +320,12 @@ class KalbachMann(AngleEnergy):
# Create continuous distribution
eout_continuous = Tabular(data[0][n_discrete_lines:],
data[1][n_discrete_lines:],
INTERPOLATION_SCHEME[intt])
INTERPOLATION_SCHEME[intt],
ignore_negative=True)
eout_continuous.c = data[2][n_discrete_lines:]
if np.any(data[1][n_discrete_lines:] < 0.0):
warn("Kalbach-Mann energy distribution has negative "
"probabilities.")
# If discrete lines are present, create a mixture distribution
if n_discrete_lines > 0:

30
openmc/data/reaction.py
View file

@ -2,6 +2,7 @@ from __future__ import division, unicode_literals
from collections import Iterable
from copy import deepcopy
from numbers import Real
from warnings import warn
import numpy as np
from numpy.polynomial import Polynomial
@ -114,8 +115,15 @@ def _get_fission_products(ace):
delayed_neutron.yield_.y *= group_probability.y[0]
total_group_probability += group_probability.y[0]
else:
raise NotImplementedError(
'Delayed neutron with energy-dependent group probability')
# Get union energy grid and ensure energies are within
# interpolable range of both functions
max_energy = min(yield_delayed.x[-1], group_probability.x[-1])
energy = np.union1d(yield_delayed.x, group_probability.x)
energy = energy[energy <= max_energy]
# Calculate group yield
group_yield = yield_delayed(energy) * group_probability(energy)
delayed_neutron.yield_ = Tabulated1D(energy, group_yield)
# Advance position
nr = int(ace.xss[idx + 1])
@ -132,7 +140,8 @@ def _get_fission_products(ace):
# Renormalize delayed neutron yields to reflect fact that in ACE
# file, the sum of the group probabilities is not exactly one
for product in products[1:]:
product.yield_.y /= total_group_probability
if total_group_probability > 0.:
product.yield_.y /= total_group_probability
return products, derived_products
@ -427,6 +436,13 @@ class Reaction(object):
# Read reaction cross section
xs = ace.xss[ace.jxs[7] + loc + 1:ace.jxs[7] + loc + 1 + n_energy]
# Fix negatives -- known issue for Y89 in JEFF 3.2
if np.any(xs < 0.0):
warn("Negative cross sections found for MT={} in {}. Setting "
"to zero.".format(rx.mt, ace.name))
xs[xs < 0.0] = 0.0
rx.xs = Tabulated1D(energy, xs)
# ==================================================================
@ -476,7 +492,15 @@ class Reaction(object):
mt = 2
rx = cls(mt)
# Get elastic cross section values
elastic_xs = ace.xss[ace.jxs[1] + 3*n_grid:ace.jxs[1] + 4*n_grid]
# Fix negatives -- known issue for Ti46,49,50 in JEFF 3.2
if np.any(elastic_xs < 0.0):
warn("Negative elastic scattering cross section found for {}. "
"Setting to zero.".format(ace.name))
elastic_xs[elastic_xs < 0.0] = 0.0
rx.xs = Tabulated1D(grid, elastic_xs)
# No energy distribution for elastic scattering