It is the first time that engineers in the tsunami-ravaged Japan have conceded the burial of the nuclear plant as a possibility.
Japan has been trying hard to restart the cooling pumps in the nuclear plant by dumping water from military helicopters as well as other methods, but there has been no signs of any headway being made.
In a sign of the growing desperation among authorities to thwart any major disaster, fire trucks poured water overnight to cool reactor No.3, considered as the most critical because of its use of mixed oxides, containing both uranium and extremely toxic plutonium.
Japan has raised the severity rating of the nuclear crisis to level 5 from 4 on the seven-level international scale, putting it at par with the Three Mile Island accident in the US in 1979, although analysts term it more serious. Chernobyl, in erstwhile USSR was 7 on that scale.
The casualty in the earthquake and the consequent tsunami is on rise. Nearly 7,000 people have been confirmed dead while another 11,000 are still missing. Almost 400,000 people young and old alike are left without a home and are shivering in the near-freeze temperatures in shelters in the northeastern coastal area of the Asian country.
Meanwhile UN atomic watchdog and health-officials have assured that the radiation levels in the Japanese capital of Tokyo was not harmful.
Government officials in the USA have also informed that "minuscule" amounts of radiation were found in California consistent with a release from Japan's damaged facility, but there were no levels of concern.