Micro cross section reader

Basic Operation

This notebook demonstrates the capabilities of the serpentTools in regards to reading group micro cross-section files. SERPENT [1] produces a micro depletion file, containing independent and cumulative fission yields as well as group cross-sections for the isotopes and reactions defined by the user. The MicroXSReader is capable of reading this file, and storing the data directly on the reader. The MicroXSReader has two methods to retrieve the data and ease the analysis. Note: in order to obtain the micro depletion files, the user must set the mdep card in the input file.

Note

The preferred way to read your own output files is with the serpentTools.read() function. The serpentTools.readDataFile() function is used here to make it easier to reproduce the examples

>>> import serpentTools
>>> mdxFile = 'ref_mdx0.m'
>>> mdx = serpentTools.readDataFile(mdxFile)

The fission yields read in from the file are stored in the nfy dictionary, where the keys represent a specific (parent, energy) pair and the corresponding values is a dictionary with fission products ids and corresponding fission yield values.

>>> # All the (parent, energy) pairs can be obtained by using '.keys()'
>>> pairs = mdx.nfy.keys()
>>> list(pairs)[0:5] # list only the first five pairs
[(902270, 2.53e-08),
 (902280, 2.53e-08),
 (902280, 0.5),
 (902280, 14.0),
 (902290, 2.53e-08)]

Each pair represents the isotope undergoing fission and the impending neutron energy in MeV.

>>> pair = list(pairs)[0] # obtain the first (isotope, energy) pair
>>> print('Isotope= {: 1.0f}'.format(pair[0]))
Isotope=  902270
>>> print('Energy= {} MeV'.format(pair[1]))
Energy= 2.53e-08 MeV

The results for each pair are dictionaries that contain three fields:

  1. fissProd list of fission products ids

  2. indYield corresponding list of independent fission yields

  3. cumYield corresponding list of cumulative fission yields

>>> # Obtain the keys in the nfy dictionary
>>> mdx.nfy[pair].keys()
dict_keys(['fissProd', 'indYield', 'cumYield'])
>>> # Print only the five first fission products
>>> print(mdx.nfy[pair]['fissProd'][0:5])
[ 250660.  250670.  250680.  260660.  260670.]
>>> # Print only the five first fission independent yields
>>> print(mdx.nfy[pair]['indYield'][0:5])
[  6.97001000e-13   1.35000000e-13   1.01000000e-14   2.57000000e-10
1.13000000e-10]
>>> # Print only the five first fission cumulative yields
>>> print(mdx.nfy[pair]['cumYield'][0:5])
[  6.97001000e-13   1.35000000e-13   1.01000000e-14   2.58000000e-10
1.13000000e-10]

Fluxes ratios and uncertainties are stored in the fluxRatio and fluxUnc dictionaries, where the keys represent a specific universe and the corresponding values are group fluxes values.

>>> # obtain the universes
>>> print(mdx.fluxRatio.keys())
dict_keys(['0'])

Cross sections and their uncertainties are stored in the xsVal and xsVal dictionaries, where the keys represent a specific universe and the corresponding values are dictionaries. The keys within the nested dictionary describe the isotope, reaction and special flag:

>>> print(mdx.xsVal['0'].keys())
dict_keys([(10010, 102, 0), (982490, 18, 0), (982510, 102, 0), (982510, 16, 0),
(982510, 17, 0), (982510, 18, 0), (40090, 107, 0)])

Each key has three entries (isotope, reaction, flag)

  1. isotope ID of the isotope (ZZAAA0/1), int or float

  2. reaction MT e.g., 102 representing (n,gamma)

  3. flag special flag to describe isomeric state or fission yield distribution number

For each such key (isotope, reaction, flag) the xsVal and xsVal store the group-wise flux values and uncertainties respectively.

>>> val = mdx.xsVal['0']
>>> unc = mdx.xsUnc['0']
>>> # Print flux values
>>> print(val[(10010, 102, 0)])
[  3.09753000e-05   3.33901000e-05   3.57054000e-05   3.70926000e-05
3.61049000e-05   3.39464000e-05   3.39767000e-05   3.98315000e-05
5.38962000e-05   7.96923000e-05   1.18509000e-04   1.73915000e-04
2.54571000e-04   3.38540000e-04   4.52415000e-04   5.98190000e-04
7.69483000e-04   1.04855000e-03   1.31149000e-03   1.67790000e-03
2.15195000e-03   2.70125000e-03   3.44635000e-03   5.04611000e-03]
>>> # Print flux uncertainties
>>> print(unc[(10010, 102, 0)])
[  1.10000000e-04   2.00000000e-05   1.00000000e-05   0.00000000e+00
0.00000000e+00   0.00000000e+00   0.00000000e+00   1.00000000e-05
1.00000000e-05   2.00000000e-05   2.00000000e-05   2.00000000e-05
2.00000000e-05   1.00000000e-05   1.00000000e-05   2.00000000e-05
2.00000000e-05   3.00000000e-05   2.00000000e-05   3.00000000e-05
4.00000000e-05   5.00000000e-05   1.70000000e-04   6.90000000e-04]

Data Retrieval

The MicroXSReader object has two get methods: 1. getFY() method obtains the independent and cumulative fission yields for a specific parent (ZZAAA0/1), daughter (ZZAAA0/1), neutron energy (MeV). If no parent or daaughter is found, the method raises an exception. The method also has a special flag that indicates whether the user wants to obtain the value corresponding to the nearest energy. 2. getXS() method to obtain the group-wise cross-sections for a specific universe, isotope and reaction.

>>> indYield, cumYield = mdx.getFY(parent=922350, energy=2.53e-08, daughter=541350 )
>>> print('Independent yield = {}'.format(indYield))
Independent yield = 0.000785125
>>> print('Cumulative yield = {}'.format(cumYield))
Cumulative yield = 0.065385

By default, the method includes a flag that allows to obtain the values for the closest energy defined by the user.

>>> indYield, cumYield = mdx.getFY(parent=922350, energy=1e-06, daughter=541350 )
>>> print('Independent yield = {}'.format(indYield))
Independent yield = 0.000785125
>>> print('Cumulative yield = {}'.format(cumYield))
Cumulative yield = 0.065385

The user can set this boolean flag to False if only the values at existing energies are of interest.

>>> indYield, cumYield = mdx.getFY(parent=922350, energy=2.53e-08, daughter=541350, flagEnergy=False )

getXS() method is used to obtain the group cross-sections for a specific universe, isotope and reaction. The method returns the values and uncertainties.

>>> # Obtain the group cross-sections
>>> vals, unc = mdx.getXS(universe='0', isotope=10010, reaction=102)
>>> # Print group flux values
>>> print(vals)
[  3.09753000e-05   3.33901000e-05   3.57054000e-05   3.70926000e-05
3.61049000e-05   3.39464000e-05   3.39767000e-05   3.98315000e-05
5.38962000e-05   7.96923000e-05   1.18509000e-04   1.73915000e-04
2.54571000e-04   3.38540000e-04   4.52415000e-04   5.98190000e-04
7.69483000e-04   1.04855000e-03   1.31149000e-03   1.67790000e-03
2.15195000e-03   2.70125000e-03   3.44635000e-03   5.04611000e-03]
>>> # Print group flux uncertainties values
>>> print(unc)
[  1.10000000e-04   2.00000000e-05   1.00000000e-05   0.00000000e+00
0.00000000e+00   0.00000000e+00   0.00000000e+00   1.00000000e-05
1.00000000e-05   2.00000000e-05   2.00000000e-05   2.00000000e-05
2.00000000e-05   1.00000000e-05   1.00000000e-05   2.00000000e-05
2.00000000e-05   3.00000000e-05   2.00000000e-05   3.00000000e-05
4.00000000e-05   5.00000000e-05   1.70000000e-04   6.90000000e-04]

The method includes a special flag isomeric, which is set to zero by default. The special flag either describes the isomeric state or fission yield distribution number.

>>> # Example of how to use the isomeric flag
>>> vals, unc = mdx.getXS(universe='0', isotope=10010, reaction=102, isomeric=0)

If the universe exist, but the isotope or reaction do not exist, the method raises an error.

Settings

The MicroXSReader also has a collection of serpentTools.settings.rc to control what data is stored. If none of these settings are modified, the default is to store all the data from the output file.

>>> from serpentTools.settings import rc
>>> rc['microxs.getFY'] = False # True/False only
>>> rc['microxs.getXS'] = True # True/False only
>>> rc['microxs.getFlx'] = True # True/False only

>>> mdx = serpentTools.readDataFile(mdxFile)
>>> # fission yields are not stored on the reader
>>> mdx.nfy.keys()
dict_keys([])

Conclusion

The MicroXSReader is capable of reading and storing all the data from the SERPENT micro depletion file. Fission yields, cross-sections and flux ratios are stored on the reader. The reader also includes two methods getFY() and getXS() to retrieve the data. Use of serpentTools.settings.rc settings control object allows increased control over the data selected from the output file.

References

  1. J. Leppänen, M. Pusa, T. Viitanen, V. Valtavirta, and T. Kaltiaisenaho. “The Serpent Monte Carlo code: Status, development and applications in 2013.” Ann. Nucl. Energy, 82 (2015) 142-150