High-temperature sodium hydroxide impinging experiment for investigating tube wastage phenomena caused by sodium-water reaction in FBR steam generator

Kurihara, Akikazu ; Ohshima, Hiroyuki; Shimoyama, Kazuhito ; Umeda, Ryota 

Sodium reacts chemically with water in case of unexpected heat transfer tube failure in a steam generator (SG) of sodium-cooled fast breeder reactors (FBRs) and exothermic reaction produces reaction field with high temperature and high corrosive action (sodium-water reaction). Adjacent tubes are damaged due to erosive and corrosive environment of the reaction field (wastage). Therefore, it is integral to evaluate such sodium-water reaction phenomena with high accuracy for the safety assessment of FBRs. For the purpose of understanding the wastage mechanism, an experiment was carried out in which sodium hydroxide (NaOH) as the main reaction product collided with the tube material under high temperature conditions simulating the reaction field. We confirmed that the erosion-corrosion rate of tube material has a tendency to increase as the temperature and velocity of NaOH are raised.