|The exact source of the radiation leaks remains unknown[AFP]
Japan has asked Russia to send a floating radiation treatment plant, which will solidify contaminated liquid waste from the country's crippled nuclear power plant, Russian media reported.
Engineers have been forced to release radioactive water into the sea as they battle to contain the disaster at the earthquake and tsunami-damaged Fukushima Daiichi nuclear plant.
After seeking help from France and the United States, Japan has now asked Russia to send the floating radiation treatment plant Suzuran, which has been used to decommission Russian submarines in nearby Vladivostok, the Interfax news agency reported.
Suzuran, one of the world's largest liquid radioactive waste treatment plants, treats radioactive liquid with chemicals and stores it in a cement form.
It can process 35 cubic metres of liquid waste a day and 7,000 cubic metres a year.
Tokyo Electric Power Co (TEPCO), the operator of the nuclear plant, has started releasing 11,500 tonnes of low-level radioactive seawater that had been used to cool overheated fuel rods after it ran out of storage capacity for more highly contaminated water.
Engineers also plan to build two giant "silt curtains" made of polyester fabric in the sea to block the spread of more contamination from the plant.
They have resorted to desperate measures to contain the damage, such as using bath salts as a dye to try to locate the source of leaks at the complex, 240 km north of Tokyo.
The exact source of the radiation leaks remains unknown.
More than three weeks after a 9.0 magnitude earthquake and massive tsunami hit northeast Japan and damaged the plant, engineers are no closer to regaining control of the facility or stopping radioactive leaks.
TEPCO said on Tuesday, it had started paying "condolence money" to local governments to aid people evacuated from around its stricken plant or affected by the radiation crisis.
The company is facing a huge compensation bill, but said it must first assess the extent of damage before paying compensation.
Analysts at Bank of America Merrill Lynch estimate that claims could top $130bn if the crisis drags on for years, with TEPCO and the Japanese government splitting the cost.
The world's costliest natural disaster has caused power blackouts and cuts to supply chains, threatening Japan's economic growth and the yen, and the operations of global firms, from semiconductor makers to shipbuilders.
The quake and tsunami left nearly 28,000 people dead or missing, thousands homeless and Japan's northeast coast a wreck.
A TEPCO official was in tears as he told a news conference: "We are very sorry for this region and those involved."
Shares of TEPCO plunged to a record low of 376 yen on on the Nikkei on Tuesday, with no end in sight to the world's worst nuclear accident since Chernobyl in 1986.
At noon the utility, which has said it may need state support to help meet its obligations, was 11.53 per cent lower at 391 amid expectations of a soaring compensation bill.
Its shares have lost more than 80 per cent of their pre-crisis value.
Schoolyard radiation tests
Meanwhile, on Tuesday, the Fukushima prefectural government started radiation measurements at schoolyards in the prefecture in the wake of the nuclear emergency.
The emergency measurement through Thursday will be conducted at some 1,400 kindergartens as well as elementary and junior high schools, prefectural officials said.
The move came as many parents have asked the authorities since the April 1 start of the new academic year if they can allow their children to walk to school or to play in the schoolyards.
The officials have confirmed that there is no problem as long as children stay outside a 30km zone around the power plant, which also includes an outer zone from 20-30km from the plant where people are advised to stay indoors.
However, some parents still showed concerns, according to officials.
Small levels of radiation from the plant have been detected as far away as Europe and the United States and several countries have banned milk and produce from the vicinity.