Research of seawater effects on thermal-hydraulic behavior at severe accident, 1; Research plan and results of preliminary experiments

Liu, W.; Nagatake, Taku ; Takase, Kazuyuki; Yoshida, Hiroyuki  ; Nagase, Fumihisa 

In the Fukushima Daiichi Nuclear Power Plant accident, seawater was injected into the reactors to cool down nuclear fuels. So far, core cooling with seawater has never been assumed and the effect of seawater on heat transfer in core is not clear. Then, effects of seawater on thermal-hydraulic behavior must be investigated to understand the phenomena occurred in the accident and to evaluate current state of the reactor cores. In this series of research work, the effects of seawater on thermal-hydraulic behavior before and after degradation of the cores will be researched experimentally. And experimental results will be incorporated to numerical simulation codes to evaluate effects of seawater on the Fukushima Daiichi Nuclear Power Plant accident. In the experimental research part, we have a plan performing two heat transfer experiments to evaluate thermal hydraulic performance of sea water and effects of salt precipitation. A preliminary experiment is performed to obtain basic information required for the experiments with salt precipitation. In this paper, outline of the research plan is explained and results of preliminary experiment is shown.