Read the rest here.
* Fuel rods appear to be melting inside three over-heating reactors
* Experts class development as 'partial meltdown'
* Japan calls for U.S. help cooling the reactor
* 180,000 people have been evacuated amid meltdown fears
The Japanese nuclear reactor hit by the tsunami went into 'meltdown' today, as officials admitted that fuel rods appear to be melting inside three damaged reactors.
There is a risk that molten nuclear fuel can melt through the reactor's safety barriers and cause a serious radiation leak.
There have already been explosions inside two over-heating reactors at the Fukushima Dai-ichi nuclear plant, and the fuel rods inside a third were partially exposed as engineers desperately fight to keep them cool after the tsunami knocked out systems.