There's been another delay in the plan to clean up the Fukushima nuclear plant. The Japan Times reported today that the country's government approved another revision to the cleanup schedule that will push removal of radioactive fuel rods from reactor Units 1 and 2 three years further down the road. This latest delay, which is due to newly uncovered damage in the storage pools, means that the cleanup is now six years behind schedule. Along with developing a safe plan for removing radioactive fuel rods and melted fuel, even just getting a good look at the state of the reactor units has proven to be pretty difficult. In February, it took just two hours for extremely high radiation levels in the reactor's Unit 2 to destroy a robot sent in to clear debris and locate melted fuel.
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.
Recent measurements of radiation levels at the incapacitated Fukushima nuclear power plant in Japan were the highest recorded since the 2011 meltdown that was the world's worst nuclear disaster since the Ukrainian Chernobyl accident in 1986. The latest radiation readings taken by the Tokyo Electric Power Co. (Tepco) Holdings Inc. were conducted inside the containment vessel of reactor 2 and showed a radiation level of 530 sieverts per hour, The Japan Times reported last week. The previous high at the reactor was 73 sieverts per hour recorded in 2012. Some experts described the radiation level as "unimaginable," the Times said. The measurements were taken in a previously unmeasured area of the plant and only at a single point, so levels in other areas of the plant were estimated to be much lower, Tepco said.
A government-backed organization in charge of supporting the decommissioning of nuclear plants is considering to propose starting the removal of melted nuclear fuel debris beginning with the No. 2 reactor at Tokyo Electric Power Company Holdings Inc.'s Fukushima No. 1 nuclear plant, officials said Thursday. Nuclear Damage Compensation and Decommissioning Facilitation Corp., or NDF, believes that the No. 2 unit is the most suitable for melted fuel removal work among the three heavily damaged reactors based on the results of its investigation into radiation levels at the reactors and the conditions inside them. In January 2018, Tepco confirmed deposits of melted nuclear fuel debris inside the No. 2 reactor containment vessel of the plant in Fukushima that was damaged in the March 2011 earthquake and tsunami. In February this year, the company made physical contact with the deposits using equipment, making much more progress in investigating the No. 2 reactor than the No. 1 and No. 3 reactors. Tepco plans to further investigate the inside of the No. 2 reactor by the end of March next year, aiming to collect sample debris.