Damage to a pipe-shaped device, including reddish-brown rust, discovered inside a containment vessel in the No. 3 reactor of the Fukushima No. 1 Nuclear Power Plant is seen. (Photo courtesy of the International Research Institute for Nuclear Decommissioning)

Tokyo Electric Power Co. (TEPCO) announced on Nov. 30 the analysis results of video footage taken inside a containment vessel at the No. 3 reactor of the ravaged Fukushima No. 1 Nuclear Power Plant in July.

The company revealed that the damage includes a broken pipe-shaped device close to the base of the reactor pressure vessel -- at which melted nuclear fuel is present.

The footage was captured by an underwater robot, bringing issues such as the broken pipe-shaped device to light for the first time.

According to TEPCO, the pipe-shaped device is believed to be part of a control rod that adjusts output from the nuclear reactor. It is thought that the device fell down from the pressure vessel as a result of the nuclear meltdown and was then damaged by the melted nuclear fuel.

Moreover, it has been confirmed that the surface of contaminated water accumulating inside the vessel is fluctuating across a wide area. It is thought that this occurred as a result of the water leaking through various holes opening up at the base of the vessel.

Furthermore, a substance believed to be fuel debris has been found attached to a thermometer cable at the base of the pressure vessel, making part of the thermometer impossible to use.

"Debris inside the reactor has been kept sufficiently cool due to a continuous supply of water," TEPCO added.

The underwater filming took place between July 19 and 22. Unwanted noise has since been removed from the video, making the footage easier to analyze.