|Fukushima's No. 2 reactor leaks containment water through a crack in a concrete pit [Reuters/Tokyo Electric Power Co]
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.
Engineers of Tokyo Electric Power Co (TEPCO), have turned to a host of improvised and sometimes bizarre methods to tame the nuclear plant after it was crippled in Japan's magnitude 9.0 quake and tsunami on March 11.
Clogging the leak
Efforts over the weekend to clog a leak in the No. 2 reactor with a special polymer, sawdust and even shredded newspapers failed to halt the flow at a cracked concrete maintenance pit near the shoreline.
The engineers have also 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.
"We must keep putting water into the reactors to cool to prevent further fuel damage, even though we know that there is a side effect, which is the leakage," Hidehiko Nishiyama, a spokesman for the Nuclear Safety and Industrial Agency, said.
"We want to get rid of the stagnant water and decontaminate the place so that we can return to our primary task to restore the sustainable cooling capacity as quickly as possible."
Dumping radioactive water
To that end, workers began dumping more than three million gallons of contaminated water from the plant into the Pacific Ocean on Monday.
TEPCO said it planned to jettison into the sea about 10,000 tons of water with radiation levels above the legal limit. The move will clear space in a waste storage building to put even more highly contaminated water, TEPCO spokesman Junichi Matsumoto said.
The government decided to allow the step as "an unavoidable emergency measure," Yukio Edano, the chief cabinet secretary said.
Radioactivity is quickly diluted in the ocean, and Edano said the dump should not affect the safety of seafood in the area.
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.