These stark images showing the heart of the Fukushima nuclear disaster zone reveal the devastation inside its destroyed reactor. The scenes were captured by a camera attached to a 50ft rod and inserted into reactor 2 at the doomed Japanese power plant, on the country's north east coast. Footage shows melted nuclear fuel attached to the pillars, walls and ceiling, as well as puddles of coolant, and debris piled up 16 to 27ins thick on the ground. Analysis of the images by the International Research Institute for Nuclear Decommissioning said the spread of debris was suggestive of several holes in the reactor floor. It is seven years since the disaster was unleashed by the Tōhoku earthquake and tsunami. But due to the deadly dose of radiation inside Fukushima, humans have to rely on robots to explore it – and even these have been left malfunctioning and broken.

The location and condition of the fuel in the three reactors hit by core meltdowns is critical information for Tokyo Electric Power Company Holdings Inc., which runs the plant. Removing the fuel debris is considered the most difficult part of decommissioning the complex. Unit 3 has the highest level of water inside at 6 meters. The fuel debris inside is presumed to have melted through its pressure vessel and settled at the bottom of its primary containment vessel. "Until today, no one has seen the situation inside reactor 3," said Tsutomu Takeuchi, senior manager at Toshiba's Fukushima Restoration and Fuel Cycle Project Engineering Department.

The operator of the crippled Fukushima No. 1 nuclear complex said Tuesday it suspended its plan to start examining the inside of reactor 1 with a self-propelled robot after having camera trouble. Tokyo Electric Power Company Holdings Inc. is checking the cause of the problem and hoping to resume the survey Wednesday in its latest attempt at ascertaining the condition of melted fuel debris in order to extract it. While preparation was underway to send the robot inside the containment vessel after launching the day's work shortly after 10 a.m., a camera monitoring inside a box containing the robot, cables and other related equipment was found to be showing no images, it said. The box is located just outside the containment vessel. The malfunctioning camera is separate from one attached to the survey robot and is used to check whether the devices are functioning properly, according to the utility. Tepco has been hoping to view the debris through a camera embedded in the shape-shifting robot in order to decide how to extract the deposits of fuel presumed to have penetrated the reactor pressure vessel and melted through the containment vessel, which is supposed to hold the fuel.

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 head of decommissioning for the damaged Fukushima No. 1 nuclear plant said Thursday that more creativity is needed in developing robots to locate and assess the condition of melted fuel rods. A robot sent inside the reactor 2 containment vessel last month could not reach as close to the core area as was hoped for because it was blocked by deposits, believed to be a mixture of melted fuel and broken pieces of structures inside. Naohiro Masuda, who heads the decommissioning unit of Tokyo Electric Power Company Holdings Inc., said he wants another probe sent in before deciding on methods to remove the reactor's debris. Reactor 2 is one of the Fukushima reactors that melted down following the 2011 earthquake and tsunami. Tepco needs to know the melted fuel's exact location as well as structural damage in each of the three wrecked reactors to figure out the best and safest ways to remove the fuel.

"We put in cameras and robots and obtained valuable images, though they were partial . . . "We first need to know the situation of the debris." Last month, the utility inserted a 10.5-meter rod with a camera on its tip into a hole in the No. 2 reactor's primary containment vessel and discovered black lumps sticking to the grating directly underneath the suspended pressure vessel, which holds the core. Tepco claims it is still unsure whether the lumps are really melted fuel that burned through the bottom of the pressure vessel. Although it is still years away from actually trying to remove the fuel, Tepco, the government and related parties are planning to decide on a basic strategy this summer and go into more detail next year.

A renewed attempt to survey reactor 2 at the damaged Fukushima No. 1 nuclear power plant failed Thursday when the latest robot probe became obstructed. The robot was inserted into the primary containment vessel at around 7:50 a.m. to approach the metal grating directly underneath the pressure vessel, where a black mass has been found. Tokyo Electric Power Company Holdings Inc. had hoped to take a closer look at what could be melted nuclear fuel, but it was forced to abandon the operation shortly after 3 p.m. The robot didn't reach its objective, Tepco said, and the utility eventually severed its controller cable. Having detected an extraordinarily high radiation level --estimated at 650 sieverts per hour -- in a preparatory survey, Tepco had hoped to obtain more precise readings, images and data needed to remove fuel and other debris to decommission the plant.

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.

The radiation level in the containment vessel of reactor 2 at the crippled Fukushima No. 1 power plant has reached a maximum of 530 sieverts per hour, the highest since the triple core meltdown in March 2011, Tokyo Electric Power Co. Holdings Inc. said. Tepco said on Thursday that the blazing radiation reading was taken near the entrance to the space just below the pressure vessel, which contains the reactor core. The high figure indicates that some of the melted fuel that escaped the pressure vessel is nearby. At 530 sieverts, a person could die from even brief exposure, highlighting the difficulties ahead as the government and Tepco grope their way toward dismantling all three reactors crippled by the March 2011 disaster. Tepco also announced that, based on its analysis of images taken by a remote-controlled camera, that there is a 2-meter hole in the metal grating under the pressure vessel in the reactor's primary containment vessel.

The radiation level in the containment vessel of reactor 2 at the crippledFukushima No. 1 power plant has reached a maximum of 530 sieverts per hour, the highest since the triple core meltdown in March 2011, oTokyo Electric Power Co. Holdings Inc. said Thursday. The reading means a person could die from even brief exposure, highlighting the difficulties ahead as the government and Tepco grope their way toward dismantling all three reactors that suffered core meltdowns in the March 2011 disaster. Tepco also announced that, based on image analysis, it has discovered a 2-meter hole in the metal grating beneath the pressure vessel inside reactor 2's containment vessel, and discovered a portion of it is warped. The hole could have been caused by melted fuel penetrating the vessel after the March 11, 2011 mega-quake and massive tsunami triggered a station blackout that crippled the plant's ability to keep the reactors cool. The new radiation level, described by some experts as "unimaginable," far exceeds 73 sieverts per hour, the previously highest radiation reading monitored in the interior of the reactor.