What’s New in 0.13.0


This release of OpenMC includes several noteworthy and unique features. Most importantly, mesh-based weight windows have been added and work with all supported mesh types (regular, rectilinear, cylindrical, spherical, and unstructured). Other additions include torus surfaces, an ability to place CAD-based geometries in universes, a feature to export/import physical properties, and a filter for particle time.

There is one breaking changing in the Python API. The openmc.deplete.Operator class used to accept Geometry and Settings objects as its first two arguments; users now need to pass a Model class instead.

The minimum supported Python version is now 3.6.

New Features

  • Variance reduction using mesh-based weight windows is now possible with the WeightWindows class.

  • Users can now model axis-aligned tori using the XTorus, YTorus, and ZTorus classes.

  • DAGMC CAD-based geometries can now be placed in a universe using DAGMCUniverse, allowing users to combine CSG and CAD-based geometry in a single model.

  • The C/C++ API has two new functions openmc_properties_export and openmc_properties_import with corresponding Python API bindings, export_properties() and import_properties(). These functions allow physical properties (temperatures, densities, material compositions) to be written to an HDF5 file and re-used for subsequent simulations.

  • A new PowerLaw univariate distribution

  • The capabilities of the Model class have been substantially expanded (e.g., the deplete(), plot_geometry(), and rotate_cells() methods).

  • A new TimeFilter class that allows tallies to be filtered by the particle’s time, which is now tracked.

  • The Source class now allows you to specify a time distribution.

  • The new CylindricalMesh and SphericalMesh can be used for mesh tallies over cylidrical and spherical meshes, respectively.

  • Geometry plotting, which used to produce the files in the unusual .ppm format, now produces .png files by default.

Bug Fixes