Earlier this month, TEPCO revealed one if its reactors had violently melted down, with fuel lying in a radioactive puddle. Today, they're saying the same is likely the case at two more of Fukushima's reactors.
The company's also conceded it's possible that melted fuel has burned its way outside of the reactor chamber, although not all the way through to the ground - the worst case meltdown scenario. With this based only on preliminary investigations, it's looking all the more unlikely that TEPCO will have the plant safely shut down within their projected 6-9 month plan. [NYT]