Japan's government has asked the operator of the stricken Fukushima nuclear plant to consider wrapping a giant sheet around the facility to contain further radioactive leaks.
The proposal calls for building framed structures around the 45-meter-high reactor buildings and then wrapping them with the sheeting, sources told Kyodo news agency on Monday.
If all of the four damaged reactors were wrapped in this manner, it would take up to two months and cost about 80bn yen ($950m), the sources said. It is not clear what kind of material would be used for the sheeting.
Atomic energy experts are sceptical about the feasibility of the plan that was proposed by a general construction firm.
They stress the risk that such sheeting would be torn apart by heat emanating from nuclear reactors, and that it would also hamper restoration work, including the spraying of water onto the reactors.
An immediate concern is a radioactive leak into the Pacific Ocean through a cracked concrete pit, which has continued despite efforts to stem the flow in a pipe upstream with a polymer capable of absorbing 50 times its own volume in water.
Engineers of Tokyo Electric Power Co (TEPCO), the operator of the plant, mixed sawdust and newspapers with polymers and cement to try to seal the crack.
"We were hoping the polymers would function like diapers but are yet to see a visible effect," Hidehiko Nishiyama, a deputy director general of the Nuclear and Industrial Safety Agency, said.
The engineers used a colour dye to trace source of the leak. White powder was poured into a tunnel from reactor number two, to ascertain if it is the origin of the contaminant leaking out into the ocean, where high iodine-131 levels have been detected.
"There is no significant change in the amount of water leaking. We haven't achieved the original goal of stopping the water," a spokesman for TEPCO said.
If the polymer fails to plug the leak, "we will consider solidifying the soil around the pit to prevent water from seeping through," the official said, adding that chemicals might be employed to achieve that.
Since the quake struck more than three weeks ago, throwing Japan into its worst post-war calamity, fears have mounted over the impact on the world's third-largest economy, and a survey Monday suggested the hurt could be massive.
The Bank of Japan said in its Tankan survey that Japanese business confidence is set to plunge in the months ahead.
The central bank's re-release of a quarterly survey from Friday showed the breakdown in the replies it received before and after the disasters.
Friday's report showed business sentiment among large manufacturers improving to "six" in March from "five" in December, but it was predicted to fall to "minus two" in the April-June period.
One of the big question marks is how the Japanese economy will be affected by a looming power shortage, triggered when the quake and tsunami knocked out a sizable portion of the nation's electricity-generating capacity.
