Japanese engineers pumped sea water into the damaged nuclear reactor, in a race to prevent a catastrophic meltdown on Tuesday.

Earlier, Tokyo Electric Power Company, said fuel rods, at a troubled nuclear reactor, have once again been fully exposed at the Fukushima plant. This happened just hours, after authorities were able to stabilize a similar emergency.

The Japanese utility company, says the exposure, happened at Unit 2 of the Fukushima plant, because a steam vent wouldn't open on Monday, causing a sudden drop of water.

That reactor and two others at the plant are overheating ,and if not cooled, will meltdown. Meanwhile, a hydrogen explosion also happened at a third reactor there.

More than 180-thousand people were evacuated from the area in recent days. Up to 160 may have been exposed to radiation - adding misery to those already devastated by the earthquake and tsunami.