Transient behavior of multi-dimensional core cooling by D-DHX in sodium-cooled fast reactors

Ezure, Toshiki ; Akimoto, Yuta ; Onojima, Takamitsu; Kurihara, Akikazu ; Tanaka, Masaaki  

In order to grasp the thermal-hydraulic behaviors during decay heat removal by dipped-direct heat exchangers (D-DHXs) in a sodium-cooled fast reactor, an experimental study was performed using a sodium experimental facility. The simulated core of PLANDTL-2 was formed by 55 hexagonal-shaped flow channel tubes, which allows to examine the cooling behavior of the simulated core region having multiple rows of fuel assemblies including the thermal hydraulic behavior to the radial direction. In this study, transient core cooling behavior in the situation after the scram with the decay heat removal using a D-DHX was examined. The time evolution of the temperature was measured in the whole system including the simulated core region. As the results, it was confirmed there was not excessively skewed temperature distribution in the radial direction in the core region.