More melted fuel has been found at the bottom of the Fukushima power planet, seven years after Japan's worst nuclear disaster. Tokyo Electric Power Company (TEPCO), the operator of Japan's crippled nuclear plant, says a long telescopic probe has successfully captured images of the fuel inside the plant's Unit 2 primary containment vessel. The images showed that at least part of the fuel breached the core, falling to the vessel's floor. TEPCO says that that the status inside the primary containment vessel is still stable, and that there are no changes in radiation levels at the site boundaries of Fukushima Daiichi's Nuclear Power Plant. A massive earthquake and tsunami in 2011 caused three reactors at the Fukushima plant to melt.

TOKYO – Images captured by an underwater robot showed massive deposits believed to be melted nuclear fuel covering the floor of a damaged reactor at Japan's crippled Fukushima nuclear plant. The robot found large amounts of solidified lava-like rocks and lumps in layers as thick as 3 feet on the bottom inside of a main structure called the pedestal that sits underneath the core inside the primary containment vessel of Fukushima's Unit 3 reactor, said the plant's operator, Tokyo Electric Power Co. On Friday, the robot spotted suspected debris of melted fuel for the first time since the 2011 earthquake and tsunami caused multiple meltdowns and destroyed the plant. The three-day probe of Unit 3 ended Saturday. Locating and analyzing the fuel debris and damage in each of the plant's three wrecked reactors is crucial for decommissioning the plant. The search for melted fuel in the two other reactors has so far been unsuccessful because of damage and extremely high radiation levels.

This image captured by an underwater robot provided by International Research Institute for Nuclear Decommissioning on Saturday, July 22, 2017 shows massive deposits believed to be melted nuclear fuel covering the floor of a damaged reactor at Japan's crippled Fukushima nuclear plant in Okuma town, northeastern Japan. The robot found large amounts of solidified lava-like rocks and lumps in layers as thick as 1 meter (3 feet) on the bottom inside of a main structure called the pedestal that sits underneath the core inside the primary containment vessel of Fukushima's Unit 3 reactor, said the plant's operator, Tokyo Electric Power Co. (International Research Institute for Nuclear Decommissioning via AP) The Associated Press

Six years after the triple meltdown at the Fukushima No. 1 nuclear power plant, recent investigations underneath the damaged reactor 2 using cameras and robots came close to identifying melted fuel rods for the first time. Experts say getting a peek inside the containment vessel of reactor 2 was an accomplishment. But it also highlighted how tough it will be to further pinpoint the exact location of the melted fuel, let alone remove it some time in the future. The biggest hurdle is the extremely lethal levels of radiation inside the containment vessel that not only prevent humans from getting near but have also crippled robots and other mechanical devices. Safely removing the melted fuel would be a best-case scenario but the risks and costs should be weighed against the option of leaving the melted fuel in the crippled reactors, some experts said.

The second robot Tokyo Electric Power Company (TEPCO) sent into Fukushima's unit 2 reactor also failed to finish its mission. Now, it's the machine's left crawler belt that stopped working (PDF) altogether, forcing TEPCO to cut off its tether and to leave it inside. Toshiba designed these scorpions specifically to examine Unit 2's condition and to locate the melted uranium fuel within. The information would help Tepco figure out the best and safest way to clean the fuel up. The power company still isn't sure whether the robot's crawler belt stopped working due to the radiation levels inside or due to all the debris the first machine wasn't able to clear.

Tokyo Electric Power Co. (Tepco) wasn't kidding when it said the radiation levels inside Fukushima's nuclear reactor are the highest they've been since its meltdown in 2011. It had to pull out the robot it sent in to find the exact location of melted uranium fuel and to do preliminary cleanup inside the reactor, because it died shortly after it started its mission. Apparently, two of the machine's cameras suddenly became wonky, darkened and developed a lot of noise after merely two hours of scraping debris away. Those are all signs of extremely high radiation levels. Tepco believes the robot endured approximately 650 Sieverts of radiation per hour if it only lasted a couple of hours.

FUKUSHIMA – Tokyo Electric Power Company Holdings Inc. said Monday that it will use a robot cleaner to remove sediment inside reactor 2 at its disaster-stricken Fukushima No. 1 nuclear power plant. The move is designed to make a full-fledged investigation into the reactor by another robot with cameras and dosimeters easier. The robot cleaner, to be placed in the reactor on Tuesday, will jet high-pressure water to remove sediment in the way of the investigative robot. The sediment may contain melted nuclear fuel in addition to corrosive coating materials. The robot cleaner will blow away sediment with water at pressures of some 7.5 megapascals and remove remaining fragments with a device similar in shape to a snowplow.