Japan's Prime Minister calling nuclear situation "very grave and serious"
TOKOYO, Japan (NBC)--Japan's prime minister is describing the situation at the crippled Fukushima nuclear power plant as "very grave and serious."
Officials suspect one of the reactor cores may have been breached, a situation that could mean more serious radioactive contamination.
The apparent leak is in Reactor Three which has been the most troubled at the Fukushima site.
Friday, Prime Minister Naoto Kan addressed the nation, "The government is stepping up monitoring efforts to control the radiation."
The problem came to light when three workers got exposed to excess radiation on Thursday. A day later, two of them were taken to a special radiation hospital in Tokyo.
Measurements of the radiation in water in the plant found it to be 10,000 times normal. Today an official was asked about the source.
"When you take a look at the water, it appears that the source of the radiation is from the nuclear reactor."
Also today, the government said people living with 18 miles of the reactor site should consider a voluntary evacuation. Earlier, they had suggested people in that zone stay indoors.
The next big questions: how much of the radiation is leaking and how much will be remain in the concrete and steel containment facility that surrounds it and how much gets into the environment.
Reactor number three, where a hydrogen explosion destroyed the building covering the containment facility, is considered the most dangerous because its fuel contains plutonium which is even more dangerous than the uranium in the other reactors.
"Nuclear engineers tell me that there is no clear path forward, there is no obvious next step. The only thing that is clear, is this is going to be dangerous and go on for weeks and maybe longer," said NBC News reporter Robert Bazell.