May 14, 2011 10:29 GMT  ·  By

Media outlets around the world report that the reactor #1 facility at the Fukushima Daiichi nuclear power plant has suffered a nuclear meltdown. The announcement was made by officials at the Tokyo Electric Power Company (TEPCO), which manages the installation.

Engineers with the company entered the reactor building at the end of last week, and determined that a significant portion of the fuel rods was left uncooled for some time. These sections, measuring up to 5 feet, melted as a result.

Each fuel rod is about 13 feet long, which means that more than a third were lost as they melted. The TEPCO teams identified a pool of melted nuclear material on the bottom of the reactor's containment chamber, and are now worried that highly-radioactive water may have made its way into the ocean.

The Telegraph reports that there is a high chance the fissionable material was hot enough to penetrate the walls containing it in the reactor. However, experts have yet to confirm that this is indeed the case.

“We will have to revise our plans. We cannot deny the possibility that a hole in the pressure vessel caused water to leak,” TEPCO spokesman Junichi Matsumoto said in an official announcement.

According to the representative, water levels at reactor #1 are now 1 meter (3.3 feet) below the base of the fuel assembly. This means that the fuel rods are fully exposed, Bloomberg reports.

“The water level is one meter below the base of the fuel assembly […] Melted fuel has dropped to the bottom of the pressure vessel and is still being cooled […] [Entombment] plans need to be revised,” added Matsumoto, referring to the plans TEPCO had of pouring concrete on the reactors.

Authorities in Japan appear to be constantly underestimating the seriousness of the situation developing at Fukushima, analysts say. At every turn, they underreported the gravity of the problems plaguing the four damaged reactors, and made overly-optimistic plans for the future.

The nuclear power plant was damaged by a devastating earthquake that struck northeast of the main islands at 2:46 pm Tokyo time (0546 GMT) on March 11. The tremor was followed by severe aftershocks and a massive tsunami.

The epicenter of the “mega” tremor was found to be some 80 miles (128 kilometers) offshore, at a depth of 24.4 kilometers (15.2 miles), which is really shallow.

According to the United States Geological Survey (USGS), the exact coordinates of the epicenter are 38.322°N, 142.369°E. The point of origin was located about 373 kilometers (231 miles) northeast of Tokyo, the nation's capital.