Effect of Gas Entrainment on Thermal-Hydraulic Performance of Sodium Cooled Reactor Core

With the view to determining whether or not gas entrained in the sodium coolant could cause overheating of a fast reactor core, the following items were studied:

1. The effect of gas entrainment on the coolant flow rate and on coolant temperature rise.

2. The effect of gas entrainment on the coolant heat transfer coefficient and film temperature drop.

Equations were derived to serve in estimating the thermal-hydraulic effect of the gas entrainment, and calculations performed therewith to obtain information on conditions corresponding to the Core A under operation in the Fermi Reactor.

The results of the present examination reveal that in the Fermi Reactor an amount of gas almost inconceivable as a practical possibility must be entrained before the coolant or the fuel surface would be heated to the boiling point of sodium.