As Japan's nuclear crisis continues to intensify authorities are racing against time to combat the threats of multiple reactor meltdowns. More than 170 thousand people have been evacuated from the country's quake-and- tsumani hit northeast, on Sunday, for fears of radioactive contamination.

 

Japanese power plant operators have been trying to keep temperatures down among a series of atomic reactors -- to prevent the current disaster from worsening.

Officials say a hydrogen explosion could go off in Unit 3 of the Fukushima Da-ichi Nuclear Complex, the latest core to face a possible meltdown.

Sunday's announcement follows a blast less than 24 hours earlier at the facility's Unit 1 reactor.

Scientists have been attempting to avert a deadly accident there, by injecting sea water into the pile, part of an urgent effort to cool down the reactors and decrease internal pressure.

Yukio Edano, Japanese Chief Cabinet Secretary, said, "Now there is a chance there might be a failure happening with the valve of the Number 3 Reactor. So, we will have to solve this problem, and need to tackle how we lower the air pressure inside the reactor. At this point, the monitor does not indicate there is radiation leaking into the surrounding area."

If they fail, the containers that house the core could melt, or even explode again, releasing radioactive material into the air.

Authorities have ordered 210,000 people out of the area, within a 20-kilometer zone around the reactors, and are providing medical services if necessary.