The critical work at the plant was stalled yesterday after smoke rose from No.2 and No.3 reactors, sparking fears of fresh radiation leaks from the area rocked by the March 11 quake of magnitude 9 and devastating tsunami that left nearly 22,000 people dead or unaccounted for in Japan''s northeast.
Although white smoke, possibly steam, was still found to be billowing from the buildings housing the No.2 and No.3 reactors, the plant's operator Tokyo Electric Power Company (TEPCO) said it was not obstructing electricity restoration work.
Firefighters and the Self-Defense Forces (SDF) personnel were also ready to restart their mission to spray tonnes of coolant water onto spent nuclear fuel pools at the No.3 and No.4 reactors, according to TEPCO.
An external power source was connected to the No.4 reactor this morning, making it the fifth of the plant's six reactors to have regained the power supply needed for the restoration of a ventilation system to filter radioactive substances from the air and some measuring tools at the control room, Kyodo news agency reported.
Following the powerful quake and tsunami, the cooling functions failed at the No.1, No.2 and No.3 reactors and their cores are believed to have partially melted.
Defence Minister Toshimi Kitazawa said that the smoke rising from the No.2 reactor were vapours caused by water-discharging operations. He said the blackish smoke was detected yesterday at the No.3 reactor as some rubble had caught fire following a rise in temperature.
Japanese defence authorities have also sought support of the US military to jointly tackle the ongoing nuclear crisis and coordination is underway, Kitazawa said.
SDF helicopters will begin measuring "drastically changing" temperatures at the plant daily except for rainy days to "relieve people''s concerns," instead of the earlier planned twice a week, he said.
Industry Minister Banri Kaieda said separately that the situation remained "extremely tough."
"It is difficult to say that things are showing progress...," he was quoted as saying.