Mechanistic Modelling of Bubble Growth in Sodium Pool Boiling

•A mechanistic model is proposed to study the bubble growth process in sodium pool boiling.•The model couples a heat transfer, force and contact angle sub-model to compute the bubble growth rate and departure radius.•Bubbles in sodium tend to be large with departure radius of the order of centimeters.•Lower the wall superheat, greater is the tendency of a sodium bubble to have a balloon-like shape at departure.