The situation at Japan's troubled Fukushima Nuclear Power Plant has slightly improved, although it still raises many questions, a source in the International Atomic Energy Agency has said.
"It seems that Japanese specialists have managed to solve the problem of water supply to reactors and their cooling. At the same time, the situation at the spent fuel storage of the No. 4 reactor remains a concern," the source said.
Fears of a large-scale nuclear disaster have been mounting in Japan since three powerful blasts hit the Fukushima plant, which was seriously damaged by Friday's earthquake and tsunami, on Saturday, Monday and Tuesday.
A fire broke out on Tuesday at the spent fuel storage pool of the plant's No.4 reactor, raising concerns that fuel rods may begin melting inside the reactor, which would cause major radiation leaks.
The IAEA source said it was unlikely that there was a serious meltdown of fuel rods inside the reactors.
Japan's Chief Cabinet Secretary Yukio Edano said on Wednesday Fukushima's blast-hit units 1, 2 and 3 were being "successfully cooled" and radiation levels around the plant did not pose a health threat. Units 5 and 6, where temperatures have been rising since Tuesday, are also being cooled, he said.
The IAEA source said there was not enough information about temperatures and radiation levels inside the reactors. On Wednesday, the Japanese authorities asked workers at the plant to evacuate temporarily as radiation levels spiked, but they were reported to have returned to the facility for further repair works a few hours later.
Soon after the first explosion hit the Fukushima plant on Saturday, the Japanese authorities assigned the situation at the plant the level 4 on the International Nuclear Event Scale (INES) that runs from 1 (anomaly) to 7 (major accident). According to the IAEA's definition, a level-4 accident is defined as having "local consequences," such as a "minor release of radioactive material."
Only the country where a nuclear accident took place has the right to estimate its scale, the IAEA source said, adding that there was a hope that the rating will not be raised to the level 5. The IAEA defines a level-5 accident as having "wider consequences."
MOSCOW, March 17 (RIA Novosti)