字幕表 動画を再生する 英語字幕をプリント It’s been six years since Fukushima, so based on their half lives: the iodine 131 has almost completely decayed and 88 percent of the cesium-134 has decayed, but the cesium-137 is only decayed about a fifth. Yikes. Up and atom friends, Trace here for DNews. In case you are somehow unaware, Fukushima Daiichi is a nuclear power facility damaged unexpectedly by a tsunami and earthquake. We’ve done some videos about it, and so have some of you. I’ve watched them. Fukushima is a touchy topic for some of you out there. I know radiation can be scary, but just to quickly reiterate, if you don’t live in the immediate area around the nuclear disaster, you’re fine. But there’s news, y’all! In 2011, the radiation levels in Reactor 2 were 73 sieverts per hour, that’s pretty high -- but the latest reading says 530 per hour (with a 30-percent error margin). For reference, depending on the organ dosed with radiation, 1 sievert can cause illness, 3 to 4 sieverts can be fatal in 30 days, 80 can cause coma and death within one hour, and 100 can cause instant death. So 530 is a lot. Like. A LOT. But it’s all inside the reactor. That’s ridiculous. The increase could have happened slowly over the last six years, as this is the first time since just after the meltdown scientists were actually able to sample the radiation. Fascinatingly, the National Institute of Radiological Sciences told Japan Times they’d never even considered working with radiation this high, which is scary. Now that the cleanup crews finally have access to Reactor 2, they think they might be able to start removing the nuclear material by 2021, some say later. And, in case you fell victim to a fake news story going around: no the reactors are not collapsing into the ocean. That said, it’s still a mess. This is a unique situation. I mean, we’ve already learned a lot about radiation from this disaster! For example, a report published in the Annual Review of Marine Science found radiation levels in the ocean (except directly around the plant) are “decreasing rapidly.” Radiation on the seabed in the harbor is higher than normal, but less than in 2011. Overall, off the coast of North America upper ocean levels might be 2 to 3 times the nuclear test levels seen in the 1960s, the study found. That would peak in 2015-16 and then drop. Another said the radioactivity levels were “rapidly returning to normal,” as of 2015. Even the dose from the seabed is less than the amount of radiation we get from natural sources annually -- less than the radiation someone gets on a flight from New York to Japan. They specifically said the risk to humans is very low. And if you’re worried about fish… a study in Integrated Environmental Assessment and Management found the biggest worry is for bottom-feeders, and those that eat them. Tuna, for example, while slightly more radioactive, are still safe to eat (not to mention, delicious). Overall radioactivity is variable, and the fish we eat are required to be tested before they’re on sent to consumers. Basically, as we’ve said before, Fukushima is and was a disaster, but like any disaster, there’s a lot to learn, and if you don’t live near the actual plant, you’re not going to experience any more radiation than you’d get from natural sources. In fact, a study in the Journal of Radiological Protection found even people from Fukushima have been exposed to four times less radiation than the Japanese government thought they would, in part because people weren’t spending a lot of time outside. They didn’t plan for this, but we can get better because of it. Another Fukushima could happen. Someone will have to invent, innovate and engineer our way out of this mess and predict and prepare for the next one. Even the cows in Fukushima have been studied! They’re experiencing 15 times normal radiation, but have no fertility or organ issues. This is the first time scientists have studied livestock in low-dose radiation, so there’s a lot to learn. It’s super interesting! In late 2016, the government estimated 70 percent of the 150,000 people evacuated six years ago will get to return home, and yet, the topsoil and a lot of tree bark has stripped after absorbing radioactive fallout, buildings were destroyed, some of the groundwater is contaminated, and the power plant will still be nearby as cleanup progresses for the next half-century -- it’s assumed to cost nearly 190 billion dollars. You really can never go home again. Want to know more about Fukushima if the radiation is affecting the west coast of the U.S.? Watch this video. How do you feel about this? Should keep using nuclear power? Why or why not? Let us know in the comments, make sure you subscribe so you get more DNews and thanks for tuning in.