Although officials of the U.S. Nuclear Regulatory Commission said Monday that conditions at the Fukushima Daiichi nuclear power plant appear to have stabilized and that the containment vessels at three reactors had not been seriously breached, smoke was reported rising from two reactors Monday evening.
The cause of the smoke was unknown, however, and it did not appear to be associated with a radiation spike.
The executive director of the NRC, Bill Borchardt, said Monday that the agency's staff in Japan reported that the three reactors that had shut down following the magnitude 9.0 Tohoku earthquake 10 days ago probably have suffered some core damage but do not appear to be leaking significant quantities of radiation.
"I say optimistically that things appear to be on the verge of stabilizing," he said.
Workers on site have been pouring massive amounts of seawater onto the reactors and spent fuel pools in an effort to keep them cool, but Monday evening white smoke was seen rising from reactor building No. 2 and gray smoke from reactor building No. 3. In the latter case, the smoke was thought to be coming from the building's southeastern side, where the reactor's spent fuel pool is located.