Fission-q-recoverable tally giving value as 0 (zero)

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1

Hello, everyone.

I am trying to extract tally from a model but the scores such as ‘fission-q-recoverable’, ‘heating’, ‘heating-local’ are giving values as zero whereas fission and flux do give actual values. Was wondering what went wrong with my code.

#defining tallies
axial_mesh = openmc.RegularMesh()
axial_mesh.dimension = [1,1,500]
axial_mesh.lower_left = [-100,-100, -121.7805]
axial_mesh.upper_right = [100,100, 121.7805]
axial_mesh_filter = openmc.MeshFilter(axial_mesh)

tally_fiss_a = openmc.Tally(name='fiss_a')
tally_fiss_a.filters = [axial_mesh_filter]
tally_fiss_a.scores = ['fission', 'flux', 'heating', 'fission-q-recoverable']
tallies.append(tally_fiss_a)

#extracting tallies after loading the statepoint file
heating_tally = sp.get_tally(name = 'fiss_a')
h_tally = heating_tally.get_slice(scores = ['fission-q-recoverable'])
h_tally = h_tally.mean.ravel()
h_tally

h_tally comes as 0.0

this is the source I have been using:

box = openmc.stats.Box(lower_left=(-100.,-100.,-125.),
                      upper_right=(100.,100.,125.),
                      only_fissionable=True);
src = openmc.Source(space=box);
settings = openmc.Settings(source= src, batches =1000, inactive = 40, particles = 10000)
settings.temperature['method'] = 'interpolation' 
settings.export_to_xml()

TIA

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2

Hi Pearl,
Have you checked the tally.o file, just to make sure that the value is also zero in your mesh tally.
Also, have you tried to use a kappa-fission score or make a dedicated tally just for fissionQ or kappa?

tally_fissQ = openmc.Tally(name='fissionQ')
tally_fissQ.filters = [axial_mesh_filter]
tally_fissQ.scores = ['fission-q-recoverable']
tallies.append(tally_fissQ)

tally_kappa = openmc.Tally(name='kappa')
tally_kappa.filters = [axial_mesh_filter]
tally_kappa.scores = ['kappa-fission']
tallies.append(tally_kappa)

The source definition looks good besides you didn’t use IndependentSource but it should still work in the previous version of openmc. Then the inactive batch is quite low (40) but I think you chose this value since you know that the Shannon entropy has been convergence by this setting right?

If so, I think there is some problem in the geometry model, have you tried debugging your model?

openmc.run( geometry_debug=True)
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