For increasing natural circulation head, coolant velocities in each core zone are adjusted by orifice at the core inlet position.
To increase safety, natural circulation in the primary circuit to cool the core, even at rated power, is also considered, possibly bringing the core thermal exchange dynamics inside the mixed convection regime.
In the bubbly flow, slug flow, churn flow and annular flow pattern, with the gas mass flow rate increasing, the natural circulation capability initially increased and then declined.
The increase in steady natural circulation flow rate due to addition of nanoparticles is found to be a function of its concentration in water.
With increasing interests in the natural circulation flow driven systems, flow instabilities occurring under low power and low pressure conditions have been receiving more research attention.
With the increased demand for passive natural circulation and gravity driven cooling options, these codes are met with the new challenge of simulating low pressure, low flow conditions.
The reactor could not meet the increasing demand for operation with natural circulation alone.
The results showed that in bubbly flow pattern, for a fixed value of gas mass flow rate, the natural circulation capability increased with the decrease of the bubble diameter.
Results showed that, for supercritical fluids natural circulation system, an increase in the system pressure and the local resistance coefficient in the cold section, and a decrease in the local resistance coefficient in the hot section could enhance the system stability.
Increased reliance on passive emergency cooling using natural circulation of gas at elevated pressure is one of the major goals for the gas-cooled fast reactor (GFR).
