Release Notes for OpenMC 0.8.0

This release of OpenMC includes a few new major features including the capability to perform neutron transport with multi-group cross section data as well as experimental support for the windowed multipole method being developed at MIT. Source sampling options have also been expanded significantly, with the option to supply arbitrary tabular and discrete distributions for energy, angle, and spatial coordinates.

The Python API has been significantly restructured in this release compared to version 0.7.1. Any scripts written based on the version 0.7.1 API will likely need to be rewritten. Some of the most visible changes include the following:

  • SettingsFile is now Settings, MaterialsFile is now Materials, and TalliesFile is now Tallies.
  • The GeometryFile class no longer exists and is replaced by the Geometry class which now has an export_to_xml() method.
  • Source distributions are defined using the Source class and assigned to the Settings.source property.
  • The Executor class no longer exists and is replaced by and openmc.plot_geometry() functions.

The Python API documentation has also been significantly expanded.

System Requirements

There are no special requirements for running the OpenMC code. As of this release, OpenMC has been tested on a variety of Linux distributions and Mac OS X. Numerous users have reported working builds on Microsoft Windows, but your mileage may vary. Memory requirements will vary depending on the size of the problem at hand (mostly on the number of nuclides and tallies in the problem).

New Features

  • Multi-group mode
  • Vast improvements to the Python API
  • Experimental windowed multipole capability
  • Periodic boundary conditions
  • Expanded source sampling options
  • Distributed materials
  • Subcritical multiplication support
  • Improved method for reproducible URR table sampling
  • Refactor of continuous-energy reaction data
  • Improved documentation and new Jupyter notebooks

Bug Fixes

  • 70daa7: Make sure MT=3 cross section is not used
  • 40b05f: Ensure source bank is resampled for fixed source runs
  • 9586ed: Fix two hexagonal lattice bugs
  • a855e8: Make sure graphite models don’t error out on max events
  • 7294a1: Fix incorrect check on cmfd.xml
  • 12f246: Ensure number of realizations is written to statepoint
  • 0227f4: Fix bug when sampling multiple energy distributions
  • 51deaa: Prevent segfault when user specifies ‘18’ on tally scores
  • fed74b: Prevent duplicate tally scores
  • 8467ae: Better threshold for allowable lost particles
  • 493c6f: Fix type of return argument for h5pget_driver_f


This release contains new contributions from the following people: