HOME
An open-source neutral particle transport and fluid depletion solver built on MOOSE
Gnat provides an SN radiation transport solver which is geared towards fluid depletion and field-based radiation sources. This capability has been primarily designed with source-driven problems in mind such as ex-core neutron activation, radiation shielding problems, and gamma photon transport from plumes. However, neutron-induced fission reactions and eigenvalue solutions to the neutron transport equation (keff) are provided from the sake of completeness. The fluid activation and depletion models provide both finite element and finite volume discretization schemes geared towards medium-fidelity simulations of dispersion-depletion problems. As Gnat is built on MOOSE, it is capable of coupling with other MOOSE-based applications (such as Cardinal) for higher-resolution simulations.
At present the documentation for Gnat is a work in progress. If there are any documentation errors or requests for features that should be documented next, please contact a member of the Gnat development team.
Getting Started
Gnat is open-source and the repository is available on GitHub - learn how to get started.
Tutorials and Documentation
Explore the tutorials and source documentation to learn about the capabilities of Gnat.
Theory and Implementation
Review the radiation transport and fluid depletion models included in Gnat.
Sample Uses
Simulation of a graphite moderated natural uranium fueled subcritical assembly using the SN radiation transport solver running in eigenvalue mode. Figure shows the thermal neutron flux.
Simulation of the neutron fields in a concrete-walled containment system caused by a small BWR using the SN radiation transport solver driven by a surface source. Figure shows the fast (group 2) scalar neutron flux.
Transient activation of Ar-40 to Ar-41 in air near a small BWR using the neutron transport and fluid activation solvers. Figure shows the activity of Ar-41 in the containment system.
Simulation of short length and time scale plume release from nuclear facilities with the tracer transport model. Figure shows the concentration of Cs-137 after 7.5 minutes of the release.
Simulation of skyshine from the decay of Ba-137m in a plume release using the coupled tracer transport and photon transport solvers. Figure shows the monochromatic 662 keV photon flux.
Acknowledgements
Gnat is primarily developed by Ontario Tech University, and is supported by an Industrial Research Chair (IRC) program. We would like to acknowledge the University Network of Excellence in Nuclear Engineering (UNENE) and the Natural Sciences and Engineering Research Council of Canada (NSERC) for funding this IRC position [funding reference number IRCPJ 549979-19].
