The International Atomic Energy Agency (IAEA) has observed positive developments in tackling the nuclear emergency at three of the reactors at Japan's Fukushima power plant.
Smoke or vapour rising from one of the reactors at the damaged plant has become less intense according to the IAEA.
With the resumption of power at the reactor units, the plant will be able to make use of onsite water pumps soon, reports the BBC.
Workers at the plant have been dumping seawater on the fuel rods in an effort to cool them and avert radiation leakage.
IAEA senior official Graham Andrew told the BBC that there have been some positive developments in the last 24 hours but overall the situation remains very serious.
Residents living near the plant have been asked not to drink tap water due to higher levels of radioactive iodine.
An earthquake and a resulting tsunami on 11 March 2011 left Japan devastated without power and water, and was the cause for three explosions and two fires at the nuclear plant.