What’s New in 0.13.2

Summary

This release of OpenMC includes several bug fixes, performance improvements for complex geometries and depletion simulations, and other general enhancements. Notably, a capability has been added to compute the photon spectra from decay of unstable nuclides. Alongside that, a new openmc.config configuration variable has been introduced that allows easier configuration of data sources. Additionally, users can now perform cell or material rejection when sampling external source distributions.

Compatibility Notes and Deprecations

  • If you are building against libMesh for unstructured mesh tally support, version 1.6 or higher is now required.

  • The openmc.stats.Muir class has been replaced by a openmc.stats.muir() function that returns an instance of openmc.stats.Normal.

New Features

  • The openmc.Material.get_nuclide_atom_densities() method now takes an optional nuclide argument.

  • Functions/methods in the openmc.deplete module now accept times in Julian years ('a').

  • The openmc.Universe.plot() method now allows a pre-existing axes object to be passed in.

  • Performance optimization for geometries with many complex regions.

  • Performance optimization for depletion by avoiding deepcopies and caching reaction rates.

  • The openmc.RegularMesh class now has a from_domain() classmethod.

  • The openmc.CylindricalMesh class now has a from_domain() classmethod.

  • Improved method to condense diffusion coefficients from the openmc.mgxs module.

  • A new openmc.config configuration variable has been introduced that allows data sources to be specified at runtime or via environment variables.

  • The openmc.EnergyFunctionFilter class now supports multiple interpolation schemes, not just linear-linear interpolation.

  • The openmc.DAGMCUniverse class now has material_names, n_cells, and n_surfaces attributes.

  • A new openmc.data.decay_photon_energy() function has been added that returns the energy spectrum of photons emitted from the decay of an unstable nuclide.

  • The openmc.Material class also has a new decay_photon_energy attribute that gives the decay photon energy spectrum from the material based on its constituent nuclides.

  • The openmc.deplete.StepResult now has a get_material() method.

  • The openmc.Source class now takes a domains argument that specifies a list of cells, materials, or universes that is used to reject source sites (i.e., if the sampled sites are not within the specified domain, they are rejected).

Bug Fixes

Contributors