Japan is looking to use its military to help pump water to the No.3 reactor and into a spent-fuel pool at the No.4 reactor of a quake-stricken nuclear plant, the nation's nuclear safety agency said on Wednesday.
It also said it was unsure if Japan's Self-Defense Forces would make another attempt to drop water by helicopter on the No. 3 reactor. An earlier attempt was aborted on Wednesday, Reuters informs.
This morning, Chinook helicopters carrying red buckets were dispatched from Kasuminome Air Base, near Sendai, to dowse the reactors from above before they too were withdrawn due to radiation fears.
A defence ministry official said the military had received orders at 4pm (0700 GMT) to send one CH47 helicopter to the Fukushima plant, but expressed reservations about the plan.
"We know how to put out forest fires, but not a nuclear plant," he said. "It's the first time for us so we don't know what the result will be, according to Telegraph.co.uk.
Radiation levels at the plant have surged and dropped repeatedly over the past few days. The most recent spike "probably" occurred "because the containment vessel in reactor No. 3 has been damaged," a spokesman for Japan's nuclear safety agency later told reporters.
The smoke was the second visible sign of trouble at the earthquake-damaged nuclear plant Wednesday.
Earlier in the day, officials spotted a fire in the plant's No. 4 reactor building. But 30 minutes later, flames were no longer visible, the Tokyo power company said, according to Sun-Sentinel reports.