Video footage shot on Jan. 26 inside the containment vessel of the No. 2 reactor at the Fukushima No. 1 nuclear power plant (Provided by Tokyo Electric Power Co.)

Tokyo Electric Power Co. sent a camera into the containment vessel of the No. 2 reactor at the Fukushima No. 1 nuclear power plant on Jan. 26 as it started a full-scale survey of the damage inside.

The probe is being conducted in advance of plans to send a robot into the heavily contaminated vessel in February to determine the locations of the melted nuclear fuel.

Nearly six years have passed since the Great East Japan Earthquake and tsunami in March 2011 triggered the Fukushima nuclear accident. However, the precise locations of the melted fuel inside the No. 2 reactor are unknown.

If those sites are confirmed, they will serve as valuable data in decommissioning the reactor.

On Jan. 26, TEPCO inserted a camera-installed pipe into the containment vessel through a hole that had been made for the survey robot “Sasori” to pass through.

The radiation level around the hole was eight sieverts per hour, a deadly exposure level for humans. Workers were forced to perform their tasks while taking cover behind a wall, which was located about two meters from the hole.

According to TEPCO, video footage taken by the camera inside the containment vessel showed that there were no obstacles around the area where Sasori is expected to pass through.

Next week, TEPCO plans to send the camera probe deeper and shoot images of the area just below the nuclear reactor. Utility officials said there is a possibility that melted fuel can be seen.

If data on the locations and conditions of the melted nuclear fuel are obtained, TEPCO and the International Research Institute for Nuclear Decommissioning (IRID) will utilize them when they study the removal method for the fuel, expected to be decided in fiscal 2018 at the earliest.

TEPCO hopes that it will start to take out the melted fuel as early as 2021.

To date, the utility has examined the inside of the containment vessel of the No. 2 reactor with an industrial endoscope three times. However, it has been unsuccessful in confirming the locations of the melted fuel.

(This article was written by Kohei Tomida and Takashi Sugimoto.)