Japanese authorities admitted Thursday one of the reactors at the crippled Fukushima Daiichi nuclear power facility suffered a partial meltdown of its core. The disclosure by the Tokyo Electric Power Company is the latest indication that the nuclear disaster was worse than previously disclosed. A TEPCO official said radioactive water had leaked from the reactor, exposing fuel rods and triggering their meltdown.

Junichi Matsumoto, TEPCO General Manager: “All the fuel is unprotected at this point, and the water levels are below that. However, temperatures in the reactor pressure vessel have cooled to 100- to 120-degrees Celsius, so we have come to the conclusion that the fuel mass, or the fuel, if you want, is actually not at the proper levels but somewhat below that, or even possibly at the bottom of the vessel.”