![]() The meltdowns triggered huge explosions that sent plumes of radioactive debris into the atmosphere, forcing the evacuation of everyone within a 12-mile radius – about 160,000 people in all. "No one is gonna send a worker in there because they'd be overexposed in just a matter of seconds." Lesley Stahl: So this is actually right where- where it all happened? The heart of the disaster, right here? Lake Barrett took us to a hill overlooking the reactors where the radiation levels are still relatively high. Killing more than 15,000 people.Īt Fukushima Daiichi, the enormous waves washed over the plant, flooding the reactors and knocking out power to the cooling pumps that had kept the reactor cores from overheating. The earthquake that caused the meltdown measured 9.0, The most powerful ever recorded in Japan and triggered a series of tsunami waves that swept away cars, houses and entire towns. Lake Barrett, who oversaw the cleanup of the worst nuclear accident in U.S. So these are unknowns that the Japanese and no one wants to deal with. Lake Barrett: Number one this is right next to the sea. Lesley Stahl: Why not just bury this place? Why not do what they did at Chernobyl? Just cover it up, bury it, and just leave it here all- you know, enclosed? And these engineering tasks can be done successfully. But there's a will here to clean this up as there was a will to put a man on the moon. Lake Barrett: It's even a bigger project in my view. 24 that the removal of nuclear fuel debris will be postponed to 2022 or later, rather than the initially scheduled 2021, due to a delay in the development of equipment to carry out the work.Lesley Stahl: Should we think of this as a project like sending someone to the moon? 3 reactors remained relatively unscathed, blocking a huge amount of radioactive substances that leaked from their containment vessels from escaping into the atmosphere, according to the NRA. In contrast, the shield plugs for the No. 1 reactor through the damaged plug, the amount of the radioactive material attached to its shield plug was estimated at 0.16 petabecquerels, considerably lower than for the No. 1 reactor slipped out of place and was damaged by a hydrogen explosion that occurred at the reactor building.Īs larger amounts of cesium 137 leaked from the No. In the triple meltdown triggered by the 2011 earthquake and tsunami disaster, the shield plug of the No. The estimated figure was 30 petabecquerels for the No. That works out to more than 10 sieverts per hour based on readings of radiation levels nearby. Radiation at such levels can kill a person if they are exposed for an hour, according to experts. The NRA’s study found that the amount of radioactive cesium 137 was estimated at 20-40 petabecquerels between the space between the top and middle layers of the shied plug of the No. The study was undertaken following investigations by Tokyo Electric Power Co., operator of the plant, and other entities, which had shown extraordinary levels of radiations there. In a study that resumed in September after about a five-year hiatus, the NRA carried out fresh measurements of radiation levels in the vicinity of the shield plugs of the No. When nuclear fuels need to be replaced, workers remove a shield plug to gain access to the interior of the containment vessel. The shield plug blocks radiation from the reactor core at normal times. It is placed above the containment vessel like a lid on the top floor of a reactor building. It has a triple-layer structure, with each layer about 60 centimeters thick. “This will have a huge impact on the whole process of decommissioning work.”Ī shield plug, made of reinforced concrete, is circular in shape and measures about 12 meters in diameter. “It appears that nuclear debris lies at an elevated place,” he said at a news conference earlier this month. Toyoshi Fuketa, chairman of the NRA, noted that removing the highly contaminated shield plugs added to the enormous difficulty of retrieving nuclear fuel debris, the most daunting part of the decommissioning process. The finding would make it exceptionally difficult for workers to move the shield plugs, raising the prospect that the plan to decommission the reactors will have to be reassessed. Radiation levels were estimated at 10 sieverts per hour, a lethal dose for anyone who spends even an hour in the vicinity, according to experts. The Nuclear Regulation Authority (NRA) said a huge amount of radioactive materials apparently had attached to shield plugs of the containment vessels in the No. 1 nuclear plant were labeled by nuclear regulators as an “extremely serious” challenge to the shutdown process and overall decommissioning of the site. Exceedingly high radiation levels found inside crippled reactor buildings at the Fukushima No.
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