Japan is on "maximum alert" after plutonium, a potentially lethal radionuclide, was detected in soil near the facility. Japan's Nuclear Industrial Safety Agency said the plutonium discovery could mean the reactor's containment mechanism had been breached, Reuters says. 

The BBC reports: 

"Officials say the priority remains injecting water to cool the fuel rods.

Mr Kan told parliament the situation at the quake-hit plant "continues to be unpredictable."

The radioactive core at the reactor may have melted through its container, raising risks of radioactive contamination at the site. The Guardian says there is little chance of saving the reactor: 

"Richard Lahey, who was head of safety research for boiling-water reactors at General Electric when the company installed the units at Fukushima, told the Guardian workers at the site appeared to have "lost the race" to save the reactor, but said there was no danger of a Chernobyl-style catastrophe."

The Japanese Daily Yomiuri reports that the current struggle is a "balancing act" between cooling failed reactors with water and draining the contaminated water so that it doesn't escape to the sea:

"Work to remove radiation-contaminated water from the turbine buildings of reactors at the Fukushima No. 1 nuclear power plant moved into full gear Tuesday, while efforts continued to cool the reactors with water.

Plant operator Tokyo Electric Power Co. earlier confirmed radioactive water that spilled out of the reactors had collected in underground trenches connected to them.

Workers were scrambling to prevent the contaminated water in the trenches from leaking into the sea. For instance, work was continuing around the clock to transfer water from the first basement floor of the No. 1 reactor's turbine building to a condenser."

France has agreed to help Japan contain the nuclear disaster, and French President Nicolas Sarkozy plans to visit Tokyo on Thursday. He will be the first foreign leader in Japan since the disaster, Reuters reports.