0.12.1.rst

What's New in 0.12.1

.. currentmodule:: openmc

Summary

This release of OpenMC includes an assortment of new features and many bug fixes. The :mod:`openmc.deplete` module incorporates a number of improvements in usability, accuracy, and performance. Other enhancements include generalized rotational periodic boundary conditions, expanded source modeling capabilities, and a capability to generate windowed multipole library files from ENDF files.

New Features

• Boundary conditions have been refactored and generalized. Rotational periodic boundary conditions can now be applied to any N-fold symmetric geometry.
• External source distributions have been refactored and extended. Users writing their own C++ custom sources need to write a class that derives from openmc::Source. These changes have enabled new functionality, such as:
  • Mixing more than one custom source library together
  • Mixing a normal source with a custom source
  • Using a file-based source for fixed source simulations
  • Using a file-based source for eigenvalue simulations even when the number of particles doesn't match
• New capability to read and write a source file based on particles that cross a surface (known as a "surface source").
• Various improvements related to depletion:
  • Reactions used in a depletion chain can now be configured through the reactions argument to :meth:`openmc.deplete.Chain.from_endf`.
  • Specifying a power of zero during a depletion simulation no longer results in an unnecessary transport solve.
  • Reaction rates can be computed either directly or using multigroup flux tallies that are used to collapse reaction rates afterward. This is enabled through the reaction_rate_mode and reaction_rate_opts to :class:`openmc.deplete.Operator`.
  • Depletion results can be used to create a new :class:`openmc.Materials` object using the :meth:`openmc.deplete.ResultsList.export_to_materials` method.
• Multigroup current and diffusion cross sections can be generated through the :class:`openmc.mgxs.Current` and :class:`openmc.mgxs.DiffusionCoefficient` classes.
• Added :func:`openmc.data.isotopes` function that returns a list of naturally occurring isotopes for a given element.
• Windowed multipole libraries can now be generated directly from the Python API using :meth:`openmc.data.WindowedMultipole.from_endf`.
• The new :func:`openmc.write_source_file` function allows source files to be generated programmatically.

Bug Fixes

• Proper detection of MPI wrappers
• Fix related to declaration order of maps/vectors
• Check for existence of decay rate attribute
• Small updates to deal with JEFF 3.3 data
• Fix for depletion chain generation
• Fix call to superclass constructor in MeshPlotter
• Fix for data crossover in VTK files
• Make sure reaction names are recognized as valid tally scores
• Fix bug related to logging of particle restarts
• Examine if region exists before removing redundant surfaces
• Fix plotting of individual universe levels
• Mixed materials should inherit depletable attribute
• Fix typo in energy units in dose coefficients
• Fixes for large tally cases
• Fix verification of volume calculation results
• Fix calculation of decay energy for depletion chains
• Fix pointers in CartesianIndependent
• Ensure correct initialization of members for RegularMesh
• Add missing import in depletion module
• Fixed several bugs related to decay-rate
• Fix how depletion operator distributes burnable materials
• Fix assignment of elemental carbon in JEFF 3.3
• Fix typo in RectangularParallelepiped.__pos__
• Fix temperature tolerance with S(a,b) data
• Fix sampling or normal distribution
• Fix for SharedArray relaxed memory ordering
• Check for proper format of source files
• Ensure (n,gamma) reaction rate tally uses sampled cross section
• Fix for temperature range behavior

Contributors

This release contains new contributions from the following people:

• Andrew Davis
• Guillaume Giudicelli
• Sterling Harper
• Bryan Herman
• Yue Jin
• Andrew Johnson
• Miriam Kreher
• Shikhar Kumar
• Jingang Liang
• Amanda Lund
• Adam Nelson
• April Novak
• YoungHui Park
• Ariful Islam Pranto
• Ron Rahaman
• Gavin Ridley
• Paul Romano
• Jonathan Shimwell
• Dan Short
• Patrick Shriwise
• Roy Stogner
• John Tramm
• Cyrus Wyett
• Jiankai Yu