My overall goal is to use OpenMC to simulate my Neutron Activation Analysis experiments. Right now, I am modeling my reactor as a very simple cylindrical source using Sirepo with a sample placed inside it. Eventually, I would like to model the entire reactor. I have been having trouble defining the source strength for my cylindrical source. I was told I should calculate the source strength by multiplying the surface area of the source (as it is defined in my code) by the experimental flux (the flux my sample experienced when it was irradiated) but this is giving me an activity that is extremely high (off by several orders of magnitude). Can anyone define what source strength would be in this case? And any suggestions on how I should define my source (eg. size, shape, etc.)? Would modeling a TRIGA Mark II reactor as a cylinder be appropriate? Should my cylindrical source be the size of the reactor core or slightly bigger than the sample?
here is a snippet of my code:
settings.source = openmc.IndependentSource(
space=openmc.stats.CylindricalIndependent(
openmc.stats.Uniform(0, 30),
openmc.stats.Uniform(0, 6.28318530718),
openmc.stats.Uniform(0, 100),
origin=[0, 0, 0]
),
angle=openmc.stats.Isotropic(),
energy=openmc.stats.Discrete(energy_bins, probabilities),
time=None,
particle=“neutron”,
constraints=None,
strength=2.4504423e+16
)
settings.run_mode = "fixed source"
settings.photon_transport = "1" == "1"
settings.export_to_xml()
openmc.lib.init(output=False)
p = openmc.lib.sample_external_source(n_samples=100)
openmc.source.write_source_file(p, "source.5.h5")
openmc.lib.finalize()
return settings
Right now my cylindrical source is modeled as the size of the reactor core and the strength value is the SA of the cylindrical source (24504.4227 cm^2) * the experimental flux value (1e12 n/cm^2/s).