Results - Dynamic Multiphysics simulation of flow blockage
Total flow blockage of one channel at the center of the GC-MR assembly was simulated by time-dependent Multiphysics coupling of Griffin, BISON and SAM. The simulated transient models a localized flow-blockage transient in only one channel. To simulate the flow blockage scenario, the flow velocity in the central coolant channel is assumed to be zero during the transient. In such scenario, only the temperature near the blocked channel increases with a slight drop in reactor power. As shown in Figure 1 and Figure 2, the relaxation time is relatively small compared since all the other cooling channels are still functional after the transient occurs. It only takes ~400 seconds for the system to reach new equilibrium. The assembly power is predicted to drop by only ~10 kW, while the local maximum temperature increases by ~40 K. The system reaches a new equilibrium after ~500 s. The 3-D power and temperature distributions after 500 s are demonstrated in Figure 3.
Figure 1: Time evolution of maximum fuel temperature
Figure 2: Time evolution of assembly power
Figure 3: The power density and temperature profiles at 500 s after the transient
Run Commands
In this simulation the parent app is Griffin, but the child apps are BISON and SAM, so we run the blue_crab code package:
mpirun -np number_of_cores /path/to/blue_crab-opt -i Griffin_steady_state.iThen, the user needs to run the Parent App for transient calculations as follows:
mpirun -np number_of_cores /path/to/blue_crab-opt -i Griffin_transient.i