On March 11, 2011, during the Great East Japan Earthquake, the interior of Unit 1 of the Fukushima Daiichi Nuclear Power Plant in Japan, where nuclear fuel melted due to a cooling system failure, was released. The interior of the reactor was severely damaged.

According to the Yomiuri Shimbun and the Tokyo Shimbun on the 31st, TEPCO put an underwater robot on the 28th and 29th to take pictures inside the ‘pedestal’, a cylindrical concrete structure with a diameter of about 5m that supports the reactor pressure vessel that contained nuclear fuel in the past on the 30th. published a picture.

This is the first time that the bottom of the pressure vessel containing the nuclear fuel of the nuclear reactor has been photographed at the time of the accident. The inside of Unit 1 is still very high in radiation, making it difficult for even robots to approach.

‘Debris’, the remains of melted nuclear fuel, and rod-shaped structures were photographed. Provided by the International Decommissioning Research and Development Organization

According to the published photos, it was confirmed that the inner wall of the nuclear power plant foundation, located between 1m from the floor, was extensively damaged. The concrete surrounding the reactor had disappeared and the rebar was exposed. Experts raised the possibility that the concrete was corroded by the strong heat from melted nuclear fuel during the 2011 accident.

At the bottom of the structure, there were also large deposits and rod-shaped structures presumed to be ‘debris’, the remains of melted nuclear fuel.

The Yomiuri Shimbun pointed out, “If concrete is damaged, there is a risk that it will not be able to withstand a strong earthquake.” The Tokyo Shimbun also reported, “If the damage to the foundation supporting the pressure vessel is severe, there is a possibility that the pressure vessel weighing about 440 tons may collapse.”

TEPCO said in a press conference on the 30th that it would “evaluate earthquake resistance through detailed analysis in the future.” After filming the reactor on this day, TEPCO plans to finish the internal investigation of Unit 1, which began in February of last year.

Source: Donga