Japan was fighting to contain what could be the world's worst nuclear disaster in 25 years after the cooling failed at a second reactor crippled by a quake which may have killed over 10,000. Japan was fighting to contain what could be the world's worst nuclear disaster in 25 years after the cooling failed at a second reactor crippled by a quake which may have killed over 10,000. Strong aftershocks continued to shake Japan's main island as the desperate search pressed on for survivors from Friday's massive earthquake and tsunami. State broadcaster NHK said more than 10,000 people may have been killed as the wall of water hit, reducing whole towns to rubble. Thousands were evacuated yesterday following an explosion and leak from the facility's No 1 reactor in Fukushima, 240kms (150 miles) north of Tokyo, where there is believed to have been a partial meltdown of the fuel rods. Engineers were pumping in seawater, trying to prevent the same thing from happening at the No.3 reactor, the government said. 'Unlike the No.1 reactor, we ventilated and injected water at an early stage,' Chief Cabinet Secretary Yukio Edano told a news briefing. Asked if fuel rods were partially melting in the No 1 reactor, Mr Edano said: 'There is that possiblity. We cannot confirm this because it is in the reactor. But we are dealing with it under that assumption.'