Hello, if the coolant is gas and gas is compressible, is the model of this program applicable

[sakura368]

For instance, I want to use helium as a coolant. I know the density, viscosity, heat capacity and thermal conductivity of helium

[MilosAtz]

Hello! Thanks for the question.

DASSH and its predecessor codes were developed for analysis of liquid metal-cooled reactors. DASSH is not capable of modeling compressible fluids. However, if the helium in your system behaves as an incompressible fluid (when the Mach number is less than ~0.3) you might be able to use it. DASSH lets you import your own material property correlations, so you can add helium as coolant. But you should be careful - it was not developed or tested for gas coolants, so you would need to carefully select/check the applicability of the built-in correlations and review the code results.

That said, I suspect that the main limitation might be that the detailed geometry in DASSH is limited to ducted pin bundles like those used in liquid metal-cooled reactors. DASSH isn't set up to model the prismatic graphite blocks or pebble beds typical of helium-cooled reactors.

Hope that's helpful! Let me know if you have any other questions.
-Milos