yani-core

Yet Another Nuclide Inventory: transmutation and activation without transport. A material, an irradiation schedule and a neutron spectrum in; inventories, activities and decay heat out.

This is the compiled distribution, and it provides the yani module itself, so the import name and the distribution name differ (as pillow provides PIL). Install yani rather than this: it pins the matching version of this wheel and is where the documentation lives.

import yani

yani.cross_section_data = "endf-b8.1"

steel = yani.materials.pnnl.material("Steel, Stainless 316", volume=1000.0)
spectrum = yani.NeutronSource(
    energy=yani.sources.Histogram([1e-5, 1e5, 1e6, 1.5e7], [1e12, 1e13, 1e14])
)
schedule = yani.PulseSchedule([
    yani.Pulse(rate=1.11e14, duration=(1, "a"), source=spectrum),
    yani.Cooldown(duration=(1, "d")),
])

results = steel.transmute(schedule=schedule)
final = results.get_final_material(steel.id or 0)
print(final.activity(), "Bq")
print(final.decay_heat(), "W")
print(final.contact_dose(), "Gy/h")
print(final.clearance_index("UK_EPR16_out_of_scope").index)

Relationship to yamc

yamc is a superset: it ships everything here plus neutron and photon transport, geometry, tallies and transport-coupled transmutation. The two are alternatives. Installing both puts two extension modules in one process, so yamc.Material and yani.Material are distinct types and the nuclear-data configuration (cross_section_data, the four transmutation_* sources) exists twice, once per package.

Pick yani when you have a spectrum already and want none of the transport stack; pick yamc when the spectrum should come from a transport solve.

What it does not do

• One stepper (ForwardEulerStepper, beginning-of-step rates). No predictor-corrector.
• Uncertainty is by resampling: pass data_uncertainty=yani.DataUncertainty() to transmute for a standard deviation on inventories, activity, decay heat and dose. It perturbs MF=33 cross sections, half-lives, decay energies, two-mode decay branching and a supplied flux spectrum's stated error. Other inputs (MF=32 resonance covariance, self-shielding, photon line intensities, the material composition) are held at nominal, and get_data_uncertainty_info lists every one it held. There are no first-order sensitivity coefficients.
• Pathways are reported per product (get_production_routes), but there is no automatic pathway search across the whole inventory.
• No ingestion or inhalation dose.
• Cross sections are read from the continuous-energy library and collapsed against your spectrum, so this reads transport-format data files even though it runs no transport. Only the sections activation needs are read, which is a small fraction of a library.