Relap thermodynamic property error

[Vnt666Skr]

Hi I am using relap to study a blowdown transient. If I let it run it with actual heat fluxes, the program terminates with error message saying thermodynamic property error with maximum time step. Reducing the time step delays the onset of the error by a fraction of a second.

Runs much longer if I halve the heat fluxes until it fails again, citing 'courant limit exceeded' error

Any ideas?

 

[Astronuc]

What flow rates or mass fluxes is one using? Are they appropriate for the heat fluxes and pressure in the correlations? One approach would be to increase the flow rates and possibly the pressure.

What version of the code is one using?

Has one reviewed the theory or user manual for information on the Courant limit and stability?

Perhaps also check the inputs.