Many experiments were performed in order to investigate the thermal-hydraulic response of the system in conditions similar to CAREM operational states. The influence of different parameters like vapor dome volume, hydraulic resistance and dome nitrogen pressure was studied. Perturbations in the thermal power, heat removal and pressure relief were applied [2].

As an example Figures 6 to 8 show the power, pressure and mass flow rate evolution during a heating power increase perturbation. As it can be seen a 5% power increase during 150 seconds produce pressure and mass flow rates increases of 2% and 3%. It was also observed that during this transient the temperature changes were very small.

The dynamic responses at low pressure and temperatures, and with control feedback loops were also studied.

It was observed that around the operating point self-pressurized natural circulation was very stable, even with important deviation on the relevant parameters.

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