Characteristics of heat transfer inside tube during sodium-water reaction in FBR steam generator

Kurihara, Akikazu ; Ohshima, Hiroyuki; Monde, Masanori*

To predict sodium-water reaction (SWR) of steam generator (SG) in fast breeder reactor with high accuracy, it is very important to understand the characteristics of heat transfer inside the tube in detail during tube failure due to SWR. Test tube was heated rapidly by high frequency current. Time averaged heat flux was estimated by using an inverse solution. It was confirmed that the derived values agreed with measured heat fluxes on the outer surface within 20% accuracy. It was found that the characteristics of heat transfer strongly depend on the flow rate. Heat transfer on the wall changed from nucleate to transient-film boiling during increasing heat flux and returned to nucleate boiling during decreasing the heat flux. The nucleate and film boiling coexisted and the area ratio of these varied with time in the transition boiling region. The adequacy of heat transfer correlations to evaluate overheating was confirmed.