A spokesperson of the Tokyo Electric Power Company Holdings (TEPCO) shows photos captured by a robotic probe inside one of the three melted reactors at the tsunami-wrecked Fukushima nuclear power plant, during a news conference at the TEPCO headquarters in Tokyo, on April 4, 2023. (PHOTO / AP)

TOKYO - Icicle-shaped objects that may contain molten nuclear fuel have been found in a reactor at Japan's crippled Fukushima Daiichi nuclear power plant, according to an image released by its operator.

Tokyo Electric Power Company (TEPCO) on Monday disclosed several images taken inside the containment vessel of the No.1 reactor, which suffered a meltdown in the 2011 earthquake and tsunami, public broadcaster NHK reported.

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One of the images showed icicle-shaped objects hanging from the upper part of the equipment that had fallen from the bottom of the pressure vessel, marking the first time objects that may contain the debris have been seen above the water, the report said.

Last year, TEPCO used a robot to survey beneath the surface of water that had accumulated at the bottom of the containment vessel of the No.1 reactor, where it spotted objects that appeared to be nuclear fuel debris

TEPCO began sending drones into the containment vessel to conduct surveys last month and plans to analyze the images to study ways to collect the debris and take other measures.

Last year, TEPCO used a robot to survey beneath the surface of water that had accumulated at the bottom of the containment vessel of the No.1 reactor, where it spotted objects that appeared to be nuclear fuel debris.

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Data gathered from past surveys and simulations indicates there is an estimated 880 tons of fuel debris inside the No.1, 2 and 3 reactors, all of which experienced meltdowns, while the No.1 reactor is believed to have the largest amount of debris at the bottom of its containment vessel, according to the report.

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Hit by a 9.0-magnitude earthquake and an ensuing tsunami on March 11, 2011, the Fukushima nuclear plant suffered core meltdowns that released radiation, resulting in a level-7 nuclear accident, the highest on the International Nuclear and Radiological Event Scale.