added decay_neutron_energy function to match existing decay_photon_energy

openmc/config.py

@@ -4,7 +4,7 @@
 import warnings
 
 from openmc.data import DataLibrary
-from openmc.data.decay import _DECAY_ENERGY, _DECAY_PHOTON_ENERGY
+from openmc.data.decay import _DECAY_ENERGY, _DECAY_PARTICLE_ENERGY
 
 __all__ = ["config"]
 
@@ -25,8 +25,8 @@ def __delitem__(self, key):
             del os.environ['OPENMC_MG_CROSS_SECTIONS']
         elif key == 'chain_file':
             del os.environ['OPENMC_CHAIN_FILE']
-            # Reset photon source data since it relies on chain file
-            _DECAY_PHOTON_ENERGY.clear()
+            # Reset particle source data since it relies on chain file
+            _DECAY_PARTICLE_ENERGY = {"photon": {}, "neutron": {}}
 
     def __setitem__(self, key, value):
         if key == 'cross_sections':
@@ -39,8 +39,8 @@ def __setitem__(self, key, value):
         elif key == 'chain_file':
             self._set_path(key, value)
             os.environ['OPENMC_CHAIN_FILE'] = str(value)
-            # Reset photon source data since it relies on chain file
-            _DECAY_PHOTON_ENERGY.clear()
+            # Reset particle source data since it relies on chain file
+            _DECAY_PARTICLE_ENERGY = {"photon": {}, "neutron": {}}
             _DECAY_ENERGY.clear()
         else:
             raise KeyError(f'Unrecognized config key: {key}. Acceptable keys '

openmc/data/decay.py

@@ -47,6 +47,10 @@
     11: 'neutrino'
 }
 
+# used to cache values, populated when decay data is loaded
+_DECAY_PARTICLE_ENERGY = {"photon": {}, "neutron": {}}
+_DECAY_ENERGY = {}
+
 
 def get_decay_modes(value):
     """Return sequence of decay modes given an ENDF RTYP value.
@@ -575,32 +579,31 @@ def sources(self):
         self._sources = merged_sources
         return self._sources
 
-
-_DECAY_PHOTON_ENERGY = {}
-
-
-def decay_photon_energy(nuclide: str) -> Optional[Univariate]:
+def decay_particle_energy(nuclide: str, particle: str) -> Optional[Univariate]:
     """Get photon energy distribution resulting from the decay of a nuclide
 
     This function relies on data stored in a depletion chain. Before calling it
     for the first time, you need to ensure that a depletion chain has been
     specified in openmc.config['chain_file'].
 
-    .. versionadded:: 0.13.2
+    .. versionadded:: 0.15.1
 
     Parameters
     ----------
     nuclide : str
         Name of nuclide, e.g., 'Co58'
+    particle : str
+        Type of particle, e.g., 'photon' or 'neutron'
 
     Returns
     -------
     openmc.stats.Univariate or None
-        Distribution of energies in [eV] of photons emitted from decay, or None
-        if no photon source exists. Note that the probabilities represent
+        Distribution of energies in [eV] of particle emitted from decay, or None
+        if no particle source exists. Note that the probabilities represent
         intensities, given as [Bq].
     """
-    if not _DECAY_PHOTON_ENERGY:
+
+    if not _DECAY_PARTICLE_ENERGY[particle]:
         chain_file = openmc.config.get('chain_file')
         if chain_file is None:
             raise DataError(
@@ -611,18 +614,63 @@ def decay_photon_energy(nuclide: str) -> Optional[Univariate]:
         from openmc.deplete import Chain
         chain = Chain.from_xml(chain_file)
         for nuc in chain.nuclides:
-            if 'photon' in nuc.sources:
-                _DECAY_PHOTON_ENERGY[nuc.name] = nuc.sources['photon']
+            if particle in nuc.sources:
+                _DECAY_PARTICLE_ENERGY[particle][nuc.name] = nuc.sources[particle]
 
         # If the chain file contained no sources at all, warn the user
-        if not _DECAY_PHOTON_ENERGY:
-            warn(f"Chain file '{chain_file}' does not have any decay photon "
+        if not _DECAY_PARTICLE_ENERGY[particle]:
+            warn(f"Chain file '{chain_file}' does not have any decay {particle} "
                  "sources listed.")
 
-    return _DECAY_PHOTON_ENERGY.get(nuclide)
+    return _DECAY_PARTICLE_ENERGY[particle].get(nuclide)
 
 
-_DECAY_ENERGY = {}
+def decay_photon_energy(nuclide: str) -> Optional[Univariate]:
+    """Get photon energy distribution resulting from the decay of a nuclide
+
+    This function relies on data stored in a depletion chain. Before calling it
+    for the first time, you need to ensure that a depletion chain has been
+    specified in openmc.config['chain_file'].
+
+    .. versionadded:: 0.13.2
+
+    Parameters
+    ----------
+    nuclide : str
+        Name of nuclide, e.g., 'Co58'
+
+    Returns
+    -------
+    openmc.stats.Univariate or None
+        Distribution of energies in [eV] of photons emitted from decay, or None
+        if no photon source exists. Note that the probabilities represent
+        intensities, given as [Bq].
+    """
+    return decay_particle_energy(nuclide=nuclide, particle="photon")
+
+
+def decay_neutron_energy(nuclide: str) -> Optional[Univariate]:
+    """Get neutron energy distribution resulting from the decay of a nuclide
+
+    This function relies on data stored in a depletion chain. Before calling it
+    for the first time, you need to ensure that a depletion chain has been
+    specified in openmc.config['chain_file'].
+
+    .. versionadded:: 0.15.1
+
+    Parameters
+    ----------
+    nuclide : str
+        Name of nuclide, e.g., 'N17'
+
+    Returns
+    -------
+    openmc.stats.Univariate or None
+        Distribution of energies in [eV] of neutrons emitted from decay, or None
+        if no neutron source exists. Note that the probabilities represent
+        intensities, given as [Bq].
+    """
+    return decay_particle_energy(nuclide=nuclide, particle="neutron")
 
 
 def decay_energy(nuclide: str):