
Japanese medical personnel check a woman evacuated from her home near the Fukushima 1 nuclear plant for radiation exposure in Hitachi city, Ibaraki prefecture, Japan, 16 March 2011. Photo by EPA/BGNES
Japan's nuclear crisis deepened Wednesday over fears that a reactor containment vessel may have been damaged, causing a radiation spike that forced the temporary evacuation of workers.
Officials asked workers at the Fukushima Daiichi nuclear plant to evacuate temporarily Wednesday after a white cloud of smoke rose above the plant and radiation levels spiked.
Japanese Cabinet Secretary Yukio Edano told a news briefing on Wednesday that the smoke or vapor above the plant may have been caused by breach in the containment structure around the No. 3 reactor's containment vessel.
"A part of the containment vessel is broken and it seems like the vapour is coming out from there. So... [it] appears to be that vapour is coming out from the broken part," Edano said.
It was the second visible sign of trouble at the earthquake-damaged nuclear plant Wednesday.
Earlier in the day, firefighters battled a blaze in the plant's No. 4 reactor building.
The containment vessel is the steel and concrete shell that insulates radioactive material inside the reactor.
In the worst-case scenario, the fuel can spill out of the containment unit and spread radioactivity through the air and water, causing both immediate and long-term health problems, including radiation poisoning and cancer.