The nuclear plant at Fukushima, pictured yesterday, with the damaged containment building at reactor 1 on the left. The nuclear cores at all three reactors are now thought to be melting.

The nuclear plant at Fukushima, pictured yesterday, with the damaged containment building at reactor 1 on the left. The nuclear cores at all three reactors are now thought to be melting.

JAPAN’S NUCLEAR AUTHORITIES say they believe that three reactors at the stricken Fukushima nuclear power plant are now melting.

The country’s chief cabinet secretary, Yukio Edano, said that although staff at the nuclear facility – where two containment buildings have been destroyed by hydrogen explosions – were unable to check for certain, it was “highly likely” that the nuclear cores at reactors, 1 2 and 3 at Fukushima I nuclear station had begun to melt.

Reuters had earlier reported that the cooling mixture of seawater and boron in the number 2 reactor had totally evaporated, with the reactor’s nuclear rods therefore totally exposed for a significant period of time.

The plant operator TEPCO had earlier said it couldn’t rule out the possibility of a nuclear meltdown in the reactor – and had admitted that a partial meltdown could already be underway.

TEPCO had previously said it believed a partial meltdown had occurred at the number 1 reactor, where a hydrogen explosion occurred at a containment building on Saturday, but retracted reports that a similar meltdown had occurred following another hydrogen blast today at the number 3 reactor.

Though authorities are adamant that the explosions at reactors 1 and 3 have not resulted in any leak, they believe the increased level of radioactive emissions detected outside the Onagawa plant 120 miles away may be a result of Saturday’s explosion at the number 1 containment building.

Authorities still maintain, however, that any meltdown can be contained by the various safety structures in place at each reactor, and that there is no significant chance of any release of radiation into the atmosphere.

AP explained that some experts would refuse to use the term ‘meltdown’ when referring to the plant, unless the nuclear fuel was to melt through the innermost chamber at each nuclear reactor.

A report in the NY Daily News cited a US military spokesman as saying 17 members of the US Navy had been contaminated with low levels of radiation during their first humanitarian efforts in Japan.

The US’s 7th Fleet, which is position around 100 miles northeast of Fukushima, had to move its ships further away in order to avoid ‘airborne radioactivity’.

The affected staff had been treated with soap and water, the military said, and “no further contamination was detected.”

The helicopters in which the marines had been travelling were also decontaminated.