openmc-dev/openmc: OpenMC 0.13.3

This release of OpenMC includes many bug fixes, performance improvements, and several notable new features. Some of the highlights include support for MCPL source files, NCrystal thermal scattering materials, and a new openmc.stats.MeshSpatial class that allows a source distribution to be specified over a mesh. Additionally, OpenMC now allows you to export your model as a single XML file rather than separate XML files for geometry, materials, settings, and tallies. Compatability Notes and Deprecations Atomic mass data used in openmc.data.atomic_mass has been updated to AME 2020, which results in slightly different masses. New Features Support was added for MCPL files to be used as external sources. Additionally, source points and surfaces sources can be written as MCPL files instead of HDF5 files. (#2116) Support was added for NCrystal thermal scattering materials. (#2222) The openmc.CylindricalMesh and openmc.SphericalMesh classes now have an origin attribute that changes the center of the mesh. (#2256) A new openmc.model.Polygon class allows defining generalized 2D polygons. (#2266) A new openmc.data.decay_energy function and openmc.Material.get_decay_heat method enable determination of decay heat from a single nuclide or material. (#2287) Full models can now be written as a single XML file rather than separate geometry, materials, settings, and tallies XML files. (#2291) Discrete distributions are now sampled using alias sampling, which is O(1) in time. (#2329) The new openmc.stats.MeshSpatial allows a spatial source distribution to be specified with source strengths for each mesh element. (#2334) The new openmc.Geometry.get_surfaces_by_name method returns a list of matching surfaces in a geometry. (#2347) A new openmc.Settings.create_delayed_neutrons attribute controls whether delayed neutrons are created during a simulation. (#2348) The openmc.deplete.Results.export_to_materials method now takes a path argument. (#2364) A new openmc.EnergyFilter.get_tabular method allows one to create a tabular distribution based on tally results using an energy filter. (#2371) Several methods in the openmc.Material class that require a volume to be set (e.g., openmc.Material.get_mass) now accept a volume argument. (#2412) Bug Fixes Fix for finding redundant surfaces (#2263) Adds tolerance for temperatures slightly out of bounds (#2265) Fix getter/setter for weight window bounds (#2275) Make sure Chain.reduce preserves decay source (#2283) Fix array shape for weight window bounds (#2284) Fix for non-zero CDF start points in TSL data (#2290) Fix a case where inelastic scattering yield is zero (#2295) Prevent Compton profile out-of-bounds memory access (#2297) Produce light particles from decay (#2301) Fix zero runtime attributes in depletion statepoints (#2302) Fix bug in openmc.Universe.get_nuclide_densities (#2310) Only show print output from depletion on rank 0 (#2311) Fix photon transport with no atomic relaxation data (#2312) Fix for precedence in region expressions (#2318) Allow source particles with energy below cutoff (#2319) Fix IncidentNeutron.from_njoy for high temperatures (#2320) Add capability to unset cell temperatures (#2323) Fix in plot_xs when S(a,b) tables are present (#2335) Various fixes for tally triggers (#2344) Raise error when mesh is flat (#2363) Don't call normalize inside Tabular.mean (#2375) Avoid out-of-bounds access in inelastic scatter sampling (#2378) Use correct direction for anisotropic fission (#2381) Fix several thermal scattering nuclide assignments (#2382) Fix _materials_by_id attribute in Model (#2385) Updates to batch checks for simulation restarts (#2390) write_data_to_vtk volume normalization correction (#2397) Enable generation of JEFF 3.3 depletion chain (#2410) Fix spherical to Cartesian coordinate conversion (#2417) Handle zero photon cross sections in IncidentPhoton.from_ace (#2433) Fix hybrid depletion when nuclides are not present (#2436) Fix bug in cylindrical and spherical meshes (#2439) Improvements to mesh radial boundary coincidence (#2443) Contributors @HunterBelanger @RemDelaporteMathurin @cfichtlscherer @valeriogiusti @keckler @kkiesling @tkittel @ebknudsen @colinelarmier @amandalund @marquezj @joshmay1 @myerspat @bam241 @aprilnovak @NybergWISC @eepeterson @gridley @paulromano @pshriwise @Shimwell @gonuke @yardasol @rockfoo