New US software models nuclear reactors for Earth and space missions

The Idaho National Laboratory (INL) and Argonne National Laboratory (ANL) have jointly developed Griffin, an advanced reactor physics modeling and simulation software designed to accelerate the development of nuclear reactors for both terrestrial and space applications. Griffin serves as a powerful digital test bed that accurately simulates core reactor processes—including neutron transport, heat flow, fuel behavior, and material stresses—under realistic operating conditions such as high temperatures and pressures. By integrating multiple physics domains like neutronics, thermal hydraulics, structural mechanics, and fuel performance into a single platform, Griffin enables detailed virtual experiments that reduce the need for costly physical prototypes and lengthy testing cycles. Built on the MOOSE (Multiphysics Object Oriented Simulation Environment) framework, Griffin offers flexibility by coupling with other physics codes and supports a range of reactor designs, including pebble bed, molten salt, sodium- and lead-cooled reactors, as well as microreactors. Its capabilities extend to modeling isotope changes, material aging, and dimensional shifts, making