Fukushima reactor no. 2 may have melted through containment, creating more problems -- but things "aren't clear"

A top official from the U.S. Nuclear Regulatory Commission said on Wednesday it was not clear that Japan's Fukushima No. 2 nuclear reactor has melted through the reactor pressure vessel.

Earlier, Democratic lawmaker Edward Markey told a House of Representatives hearing on the nuclear disaster that the NRC had told him the core had melted through the vessel.

"That's not clear to us, nor is it clear to us that the reactor has penetrated the vessel," said Martin Virgilio, deputy executive director for reactor and preparedness programs at the NRC. (Source)