0.13.0.rst

What's New in 0.13.0

openmc

Summary

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 ~openmc.Geometry and ~openmc.Settings objects as its first two arguments; users now need to pass a ~openmc.model.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 ~openmc.WeightWindows class.
• Users can now model axis-aligned tori using the ~openmc.XTorus, ~openmc.YTorus, and ~openmc.ZTorus classes.
• DAGMC CAD-based geometries can now be placed in a universe using ~openmc.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, ~openmc.lib.export_properties and ~openmc.lib.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 ~openmc.stats.PowerLaw univariate distribution
• The capabilities of the ~openmc.Model class have been substantially expanded (e.g., the ~openmc.model.Model.deplete, ~openmc.model.Model.plot_geometry, and ~openmc.model.Model.rotate_cells methods).
• A new ~openmc.TimeFilter class that allows tallies to be filtered by the particle's time, which is now tracked.
• The ~openmc.Source class now allows you to specify a time distribution.
• The new ~openmc.CylindricalMesh and ~openmc.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

• Fix for shared fission bank memory errors
• Make sure properties export only happens from root process
• Fix pathlib use error in openmc-ace-to-hdf5
• Fix DAGMC and libMesh variable in CMake config
• Fix bug associated with volume calc in MG mode
• Add missing Settings.write_initial_source property
• Bug fixes for specifying Materials.cross_sections
• Removing Legendre filter in diffusion coefficient results
• Ensure particles lost during event_calculate_xs are terminated
• Fixed parsing of xsdir entries with a continuation line
• openmc.RegularMesh attribute consistency
• Ensure secondary particles below energy cutoff are not created
• Allow compilation with g++ 11
• Depletion-related bug fixes
• Miscellaneous bug fixes
• Fixes for various bugs
• Reset triggers in openmc_reset

Contributors

• Hunter Belanger
• Helen Brooks
• Andrew Davis
• Valerio Giusti
• Jeff Hammond
• Yuan Hu
• Andrew Johnson
• Miriam Kreher
• Amanda Lund
• Adam Nelson
• April Novak
• Ariful Islam Pranto
• Gavin Ridley
• Paul Romano
• Olaf Schumann
• Jonathan Shimwell
• Patrick Shriwise
• John Tramm