The close marks the first steepest percentage fall in the Nikkei 's history . At more than 1,390 point , the Nikkei plunged one points , or nearly 17 percent . Kan : Risk of further releases of radioactive material from Fukushima Daiichi plant `` very high '' Tokyo market opened shortly after `` explosive impact '' reported at nuclear reactor .
The close marks the third steepest percentage fall in the Nikkei 's history . At one point , the Nikkei plunged more than 1,390 points , or more than 14 percent . Kan : Risk of further releases of radioactive material from Fukushima plant `` very high '' Tokyo market opened shortly after `` explosive impact '' reported at nuclear reactor .