Experimental study of seawater effects on thermal-hydraulic behavior for severe accident conditions

Uesawa, Shinichiro  ; Nagatake, Taku ; Jiao, L.; Liu, W.; Takase, Kazuyuki; Yoshida, Hiroyuki  

In order to evaluate the seawater effects on the thermal-hydraulic behavior in a severe accident like the Fukushima Daiichi NPS accident, we compared the thermal-hydraulic behavior of the pure water, the manmade seawater and the NaCl solution in an internally heated annulus. On conditions without boiling, the heat transfer of the manmade seawater and the NaCl solution can be estimated by Dittus-Boeltter equation, considering physical properties of salinity. On conditions with boiling, boiling curves of the manmade seawater and the NaCl solution were qualitatively coincident with Rohsenow equation, although superheating of the heated wall surface in these fluids was only a little lower than estimated values by the equation. Therefore, it was confirmed that the effects of the seawater on the heat transfer were small.