Japan said on Monday it was still on target to achieve the shutdown of damaged reactors at a crippled nuclear plant by around the year-end, despite damage being worse than earlier thought.
"We will manage to continue working without changing the timeline prospects of putting (the reactors) in to a state of cold shutdown in six to nine months" from April 17, Prime Minister Naoto Kan said in parliament.
Kan was referring to the "roadmap" that Tokyo Electric Power Co (TEPCO) announced on April 17 to bring closure to the world's worst atomic crisis in 25 years, sparked by the March 11 tsunami which hit its Fukushima Daiichi plant.
The premier's pledge came despite the abandonment of the latest attempt to cool the number one reactor at the plant by filling the containment chamber with water.
TEPCO said that around 3,000 tons of highly radioactive contaminated waste water had leaked through holes created by melted fuel into the reactor basement, forcing officials to think of ways to pump it out and process it.
Nine weeks after the disaster, TEPCO last week gave a snapshot of the stricken plant that confirmed experts' fears, in which it said fuel rods inside reactor one had been fully exposed to the air and had melted.
TEPCO said the fuel started melting just five hours after the quake and most of it had fallen into the bottom of the reactor's pressure vessel 16 hours after the earthquake and tsunami that has left 25,000 dead or missing.
But it has also said that relatively low temperatures indicated that the fuel is now submerged under water at the bottom of the vessel, preventing it from going into full meltdown.
TEPCO has targeted cold shutdowns of all four damaged reactors at the Fukushima plant between October and January.
The company is to release a review of the roadmap on Tuesday, one month after the announcement of the plan.
Also on Tuesday the government will issue a timeframe detailing when evacuated residents near the plant will be able to return home, Kan said.
More than 80,000 people have been forced from homes, farms and businesses in a 20-kilometre (12-mile) zone around the plant that has leaked radiation into the air, ground and sea.
The power company faces compensation payments worth tens of billions of dollars for victims of the world's worst nuclear accident since Chernobyl a quarter of a century ago.
TEPCO and the government have yet to release estimates for the payout bill, but analysts say it could range from four trillion yen ($50 billion) to 10 trillion yen depending on how long the nuclear crisis lasts.