Japan earthquake: Battle to cool second nuclear reactor

Japanese technicians are battling to lower the pressure in a second nuclear reactor at Japan's earthquake-damaged Fukushima power station, which was hit by a big explosion on Saturday.

Officials say reactor 3 lost its emergency cooling system. A similar problem led to a blast at reactor 1 at the plant on Saturday.

About 170,000 people have been evacuated from the area near the plant, as Chris Hogg reports from Tokyo.