Multiphysics · Particle transport · CFD & heat transfer
FissionFusionGeneral nuclear

Cardinal.

Cardinal is an open-source MOOSE application that embeds the GPU spectral-element CFD code nekRS and the Monte Carlo code OpenMC inside the MOOSE framework, so they exchange temperatures, densities, heat fluxes and tallied power with MOOSE and other MOOSE-based solvers through in-memory transfers rather than files. It targets high-resolution coupling on CSG or CAD geometry for fission and fusion component analysis.

Hub integration plannedUpstream exampleSources checked 2026-10-10
Engineering questions it helps answer
  • What is the coupled neutronics–thermal steady state of a component when Monte Carlo transport is iterated with heat conduction or CFD?
  • What nuclear heating and temperature field does a CAD-defined fusion component see when OpenMC transport is coupled to MOOSE heat conduction?
  • How does conjugate heat transfer between nekRS and a solid-conduction model affect wall temperatures in cooling channels?
Physics scope
  • OpenMC neutron and photon transport on CSG and CAD geometry with temperature, density and tally feedback
  • nekRS incompressible and low-Mach CFD with turbulence modelling
  • Conjugate heat transfer between nekRS and MOOSE heat conduction
  • Adaptive mesh refinement on OpenMC mesh tallies; multigroup cross-section generation
  • Forward uncertainty quantification through MOOSE stochastic tools
  • Coupling to other MOOSE applications through MultiApps and Transfers

Limitations

Built from source with MOOSE, OpenMC and a Cardinal-specific nekRS fork as submodules; the nekRS update in 2026 was a breaking change for inputs. CAD tutorials need a DAGMC-enabled build, mesh downloads and Coreform Cubit, and many tutorials are production-scale models that need HPC resources. Only one tagged release exists; development happens on the devel branch.

Fusion relevance

A general nuclear multiphysics tool that the project describes as serving both fission and fusion. Most tutorials are fission models, but the official documentation includes a CAD-based tokamak tutorial coupling OpenMC transport to MOOSE heat conduction and a breeder-blanket module in its gallery, and the development team includes a UKAEA member.

Upstream examples

Published by the project itself. These are the project's own tutorials, not Morton Labs runs.

Reference workflows on this site
Upstream example

Cardinal LWR pincell: OpenMC transport coupled to MOOSE heat conduction

For one pressurised-water-reactor fuel pin, what converged fission heat-source distribution and solid temperature field result when OpenMC eigenvalue transport with temperature feedback is iterated against a MOOSE heat-conduction solve?

Upstream exampleCardinalOpenMCMOOSE
People
Editorial spotlight

Paul Romano

Computational scientist at Argonne National Laboratory; project lead of OpenMC; curator of Awesome Nuclear

Computational Scientist · Argonne National Laboratory

Awesome NuclearCardinalendf-pythonOpenMC
Paul RomanoCore developerCurrent

Listed among the current Cardinal development team on the project's contact page, which does not assign individual titles.

Evidence: cardinal.cels.anl.gov · checked 2026-10-10

Roles name a specific relationship with evidence. Authorship of a paper is not maintainership, and a listed person is not a Morton Labs partner or endorser.

Source collections

This entry was written by Morton Labs from public sources and last checked on 2026-10-10. Spotted an error, or want something changed or removed? Email zach@mortonlabs.ai with the page address.

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