You can create a tally for the fast neutron flux (this example doesn’t have a spatial filter but you may want to include one):
tally = openmc.Tally()
tally.filters = [
openmc.EnergyFilter([E_low, E_high])
]
tally.scores = ['flux']
...
model.tallies.append(tally)
Then, when you run a depletion calculation, each statepoint file (openmc_simulation_n#.h5
) will have the result of that tally. You can multiply the tally result (flux) by the depletion timestep length to get a fluence. Also, it is up to you to define what “fast” is, that is, you would need to select E_low
and E_high
.