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First contact made with melted nuclear fuel at Fukushima plant
- fouc 8y agoInteresting, seems like it's been tough to build robots to withstand the radioactive materials in the water. https://www.sciencealert.com/the-robots-sent-into-fukushima-have-died https://www.sciencealert.com/the-robots-sent-into-fukushima-...
- Ancalagon 8y ago> Built by Toshiba Well there's your problem!
- rememberlenny 8y agoCan someone add (2016) as the publish date? Edit: I don't know why but the first time I clicked the link, it went to a 2016 published piece. Please ignore!
- dvh 8y agohttps://en.wikipedia.org/wiki/Corium_(nuclear_reactor) https://en.wikipedia.org/wiki/Corium_(nuclear_reactor)
- En_gr_Student 8y agothis is good that they are there. It means that the radioactive material can be sequestered. It means that the radioactive material can be inventoried, and escapee content determined.
- Animats 8y agoNot there yet. They got in far enough to touch it with a grabber. Didn't get a sample yet. Removing it for disposal is years away.
- jrs235 8y agoAre all the rainbow colored pixels in the picture caused by radiation hitting the camera sensor?
- java-man 8y agoyes
- furyofantares 8y agoAll pixels in the picture are caused by radiation hitting the camera sensor
- dimensi0nal 8y agoI assume the commenter was referring to ionizing radiation.
- db48x 8y agoIn a CCD, even photons of visible light are ionizing radiation. The light causes electrons to pop out of a semiconductor and get caught in a capacitor, where they are stored long enough to be read out as a voltage, and turned into a number.
- est31 8y agoI don't think so. I rather think it's water droplets acting as little prisms. Radiation would hit the camera sensor in a random pattern and the effect would decay over time. A bit like how you determine pi with the monte calro method by throwing points at a circle and then checking whether they are inside or not. I found a video of the robot on YouTube [1] and it seems that the rainbow patterns don't follow the "monte carlo throwing" pattern, but their location depends on the scene. I don't know how radiation would affect a CMOS sensor, but I would guess it to be similar to what strong light is doing, e.g. when you point your camera into the sun. What then happens is an effect called "blooming": CMOS sensors work by photodiodes converting light to electric potential. If the radiation that reaches one of the photodiodes in the sensor plane is strong enough, the potential would jump to the other sensors next to it, causing a large bright field in the digital image. Edit: Oh and it seems that the material itself is reflecting light in a rainbow pattern, but that's not the same as "ionizing radiation hitting the sensor". Edit2: it could just be oil. Oil on water causes rainbow like artifacts. [1]: https://www.youtube.com/watch?v=cyKEVD4oC4s https://www.youtube.com/watch?v=cyKEVD4oC4s
- 21 8y agoDon't forget, nuclear energy is extremely safe and we should build more of it. What happened at Fukushima literally can't happen due to how safe this technology is.
- sctb 8y agoWe've already asked you many times to please follow the guidelines and post substantively, so we've banned the account. This isn't a sarcastic flamewar site.
- mimixco 8y agoIt took 10 years to even get a robot that could get close to the fuel... and people still ask if nuclear might not be as bad as coal! The truth is that accidents like this can never be cleaned up or salvaged. It's time to move away from nuclear, as other countries have already figured out. Fortunately for us in the US, the last nuclear plant under construction today will likely be cancelled, as the last two were. There are no plans to build another one here. That doesn't relieve of us of the chance of a homegrown Fukushima on American soil, but it shows that the future isn't nuclear for environmental and cost reasons -- of which "decommissioning" costs billions, even if there's no meltdown.
- Kuinox 8y agoYes, and move away to what ?
- toomuchtodo 8y agoSolar, wind, storage. Fusion at a distance. EDIT: "20 years from now" is still faster than any nuclear generator getting built.
- aurailious 8y agoSo a mixture of unreliable, expensive, and "20 years from now".
- moate 8y agoDon't forget the chemical byproducts of producing solar and storage. All options are trade offs, and I don't understand why "perfect" keeps preventing us from just getting "better".
- hanniabu 8y agoWith many recent breakthroughs, fusion is now seen as very viable and just needs funding to finish it off. The last of the hard problems are solved and they just need to pull it all together and "adjust for rounding errors", so to speak.
- simmanian 8y agoHas there been a proper study done on how dangerous it is to live in areas around the plant, or how safe it is to eat produce grown from Fukushima and all the fish caught in the area? There's been so much rumor and fake news around this topic that I don't know what to think.
- acidburnNSA 8y agoAbsolutely yes. The United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) does reports every year or so on the status. Here's the 2017 one [1]. [1] http://www.unscear.org/docs/publications/2017/UNSCEAR_WP_2017.pdf http://www.unscear.org/docs/publications/2017/UNSCEAR_WP_201...
- simmanian 8y agoThanks. I think page 20 has a lot of information I'd been looking for.
- acidburnNSA 8y agoYes. And I recommend having https://xkcd.com/radiation/ https://xkcd.com/radiation/ handy as you read through those numbers. The units are consistent.
- jessriedel 8y agoFrom the executive summary (for others): > ...its assessment of the exposures and effects due to the nuclear accident after the 2011 great east Japan earthquake and tsunami... It had concluded in that report that, in general, doses were low and that therefore associated risks were also expected to be low. A discernible increase in cancer incidence in the adult population of Fukushima Prefecture that could be attributed to radiation exposure from the accident was not expected. Nevertheless, the report noted a possibility that an increased risk of thyroid cancer among those children most exposed to radiation could be theoretically inferred, although the occurrence of a large number of radiation-induced thyroid cancers in Fukushima Prefecture—such as occurred after the Chernobyl accident—could be discounted because absorbed doses to the thyroid after the accident at Fukushima were substantially lower. It had also concluded that no discernible changes in birth defects and hereditary diseases were expected and that any increased incidence of cancer among workers due to their exposure was expected to be indiscernible because of the difficulty of confirming a small increase against the normal statistical fluctuations in cancer incidence. The effects on terrestrial and marine ecosystems were expected to have been transient and localized.
- ChuckMcM 8y agoWhile I realize it was likely impractical to meltdown reactors just to develop the technology to clean them up, I find the process here pretty interesting. A lot of good engineering has gone into the effort, and the engineering challenges (and risks) of post runaway reactors has gotten a lot more data. The Chernobyl folks just entombed everything, which is a one approach, even though they can "walk up to"[1] the remains of the nuclear fuel which they call the "elephant foot." I also find it interesting that the "China Syndrome"[2] speculation is pretty much completely debunked. Molten/melted fuel diffuses into the material it is melting into until it loses criticality and then freezes where ever it is. All modern reactors have a borosilicate sand pile underneath the reactor. The boron acts as a neutron absorber (poison) which stops the chain reaction once the fuel has been glassified by the silicate. [1] It is too radioactive for that to be literally true, but it is on a floor with direct access rather than being underwater and only accessible through cracks as the Fukishima fuel is. [2] Speculation that a blob of melted core material would just keep melting into the ground until it "got to china" (which in fact would be interrupted by getting to the earths core). [3] EDIT: Corrected for the effects of Boron on the reaction acting as a neutron poison (absorbs neutrons) rather than a moderator (which just bounces them around)
- cpeterso 8y ago> melted core material would just keep melting into the ground until it "got to china" aka "China Syndrome", just like the 1979 film: https://en.wikipedia.org/wiki/Nuclear_meltdown#China_syndrome https://en.wikipedia.org/wiki/Nuclear_meltdown#China_syndrom...
- __m 8y agoNow that convincingly debunks the China syndrome, China is obviously not the antipode to Fukushima
- petschge 8y agoBoron actually mostly acts as a neutron poison, i.e. it absorbs neutrons. That way further (stimulated) decay of other nucleii that were hit by a neutron is eliminated and the chain reaction stops, reducing the production of thermal energy. A moderator on the other hand inelastically scatters neutrons, converting some of the kinetic energy of the neutrons to heat and leaving a slower neutron. Moderators are used in reactors to bring neutrons down from their initial velocity to velocities where they are more likely to stimulate fission in another nucleus.
- JosephRedfern 8y agoForgive the macabre question, but if a human (or other living creatue) were to venture in to the plant and collect this fuel by hand, how long would they survive? I'm in no way suggesting that this is an option, of course -- just curious.
- x3n0ph3n3 8y agoThis might interest you and give you a benchmark for the lethality of approaching it: https://rarehistoricalphotos.com/the-elephant-foot-of-the-chernobyl-disaster-1986/ https://rarehistoricalphotos.com/the-elephant-foot-of-the-ch... > After just 30 seconds of exposure, dizziness and fatigue will find you a week later. Two minutes of exposure and the body cells will soon begin to hemorrhage; four minutes: vomiting, diarrhea, and fever. At 300 seconds you have two days to live. > All of the fire fighters and people who worked in building the sarcophagus died around a year or so after the event.
- java-man 8y agoI've read (long time ago) the US did tests on monkeys, exposing them to large neutron doses. There is also a number of human cases of exposure to large neutron doses, starting with Louis Slotin https://en.wikipedia.org/wiki/Louis_Slotin https://en.wikipedia.org/wiki/Louis_Slotin
- samstave 8y agoYou should watch this documentary on Chernobyl: >According to Vyacheslav Grishin of the Chernobyl Union, the main organization of liquidators, "25,000 of the Russian liquidators are dead and 70,000 disabled, about the same in Ukraine, and 10,000 dead in Belarus and 25,000 disabled", which makes a total of 60,000 dead (10% of the 600,000 liquidators) https://en.m.wikipedia.org/wiki/Chernobyl_liquidators https://en.m.wikipedia.org/wiki/Chernobyl_liquidators They had guys running in and throwing lead bricks - and some of the scientists died by giving their life to get in and take video of the meltdown. https://www.youtube.com/watch?v=ti-WdTF2Qr8 https://www.youtube.com/watch?v=ti-WdTF2Qr8 These guys knew they were doomed. But they had freaking reportedly 700,000 men attack that problem.
- mehrdadn 8y agoAre there not any suits that protect against the radiation to let them go in and do some things by hand? If there are but it's still not a good idea -- why?
- roywiggins 8y agoGamma radiation goes through everything. The only thing that stops it is mass and distance. You can only wear a certain amount of lead before you collapse. The amount of radiation is just too high.
- petschge 8y agoGamma radiation not so much simply makes it through everything, but it does indeed take a lot of shielding to attenuate to save level if there is enough radiation to begin with. The fact that it interacts with stuff is actually what makes it dangerous. If it went through every thing it would not interact with the worker either and would not pose a thread to them. Btw. there is a type of radiation that is practically like that: neutrinos. Impossible to shield against, but also completely harmless if you are not standing right next to a super nova.
- tomatotomato37 8y ago>Impossible to shield against, but also completely harmless if you are not standing right next to a super nova There was actually a fun what-if based on that: https://what-if.xkcd.com/73/ https://what-if.xkcd.com/73/
- meenzu 8y agoThanks for the answer, just curious would the lead sheet have holes thorough it if you put it up to that radiation? I'm picturing a sheet of paper with bullet holes through it. Or is there a better analogy of what is going on?
- petschge 8y agoIt would not have holes in it. The main reason why the gamma radiation makes it through is because it never interacted with any of the lead. And even if a (unlucky) gamma photon interacts inside the lead sheet it would not do much damage there. The only thing that really do damage to the material is neutron radiation and even there the damage is on the microscopic level (atoms getting knocked out of place) than anything macroscopic.
- ctoth 8y agoI suspect I am not the only person who saw "First contact made" at the top of HN and for one brief, shining moment lived in a far more interesting Universe.
- komali2 8y agoThis has happened to me here and there on various aggregators over the years, and every time I get the goosebumps, and ride it out without fully reading the headline all the way, letting myself imagine, think "yeah, this is probably how I'd find out about it!" To me it would feel like discovering magic, or the existence of latent psychic abilities in humans. A reality shattering event.
- wolco 8y agoSomething tells me Trump would be the most unlikely so most likely person to start disclosing. I feel psychic abilities will be a breakthrough in our lifetime. Time travel never. Communicating with the spirits or dead quite possible or completely foolish. Time will tell.
- ianai 8y agoIt’s a poor choice of words for any headline that isn’t contact with ET.
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- sixothree 8y agoI don't want to die not knowing.
- bdamm 8y agoI hope an alien friend visits me at my deathbed.
- Asparagirl 8y agoPeople should check out Safecast, which is a citizen-led open data network for monitoring and publishing radiation readings, including an open API: https://blog.safecast.org/ https://blog.safecast.org/ They're using low-cost open hardware, including Arduino: https://github.com/Safecast/General/wiki/Safecast-Devices https://github.com/Safecast/General/wiki/Safecast-Devices Here's their latest heatmap (well, radiation map) for Japan, centered on the Fukushima area: https://safecast.org/tilemap/?y=37.14&x=140.67&z=8&l=0&m=0 https://safecast.org/tilemap/?y=37.14&x=140.67&z=8&l=0&m=0
- Asparagirl 8y agoThey also got volunteers to take radiation readings in and around the Santa Susanna Mountains near Los Angeles, to verify that radioactive waste from an old reactor meltdown there was not kicked up during the recent wildfires. (It was not, luckily.) https://safecast.org/tilemap/?y=34.16&x=-118.735&z=11&l=0&m=0 https://safecast.org/tilemap/?y=34.16&x=-118.735&z=11&l=0&m=...
- acidburnNSA 8y agoDo you know how they're communicating the expected health effects of dose rates like these? For instance the yellow is 4 uSv/hr, roughly 10x a normal dose rate in the USA.
- Asparagirl 8y agoI don't know that, I'm sorry, but you can e-mail them or Tweet them and find out.
- zyztem 8y agoThere is better pictures and explanation at TEPCO site: https://www7.tepco.co.jp/wp-content/uploads/handouts_190213_01_e-6.pdf https://www7.tepco.co.jp/wp-content/uploads/handouts_190213_...
- mempko 8y agoWhat strikes me is just how inept the Japanese are in handling Fukushima compared to the USSR during the much worse Chernobyl disaster. The USSR responded quickly and it took just 8 months to entomb the reactor. Over 600k people worked to handle Chernobyl. Fukushima, on the other hand, is still at risk of another disaster, 10 years later. The Japanese government and power company under-handled the situation and lied for years about it's severity. For example that 300 tons of polluted water was going into the pacific every day for 5 years.
- avar 8y agoWhat the Soviet Union accomplished at the cleanup of Chernobyl likely wouldn't have been possible without a wanton disregard for the value of human life only possible in a totalitarian state, the details of which are discussed in other comments. I don't think the lack of will or ability on the part of Japan to doom thousands of people to death by radiation in the course of a speedy cleanup can be described as ineptitude.
- stordoff 8y ago> The USSR responded quickly and it took just 8 months to entomb the reactor. At a gross cost to human life[1], and in a way that leaves the problem there - work is _still_ to contain and clean up the reactor. There are good reasons for not doing the same here. The sarcophagus was never intended to be a permanent solution, and was unsuccessful in completely containing the accident: Sr-90 and Pu-239 were leaching into the surrounding water table, and some have suggested that the rainwater and remaining nuclear fuel posed the risk of restarting the nuclear chain reaction[2]. [1] death figures are controversial, and vary wildly, but 600,000 people were involved in the cleanup, some of whom will have been put at risk. [2] https://outline.com/fTk4GX https://outline.com/fTk4GX
- mempko 8y agoI'm curious, what would have been a better approach the USSR could have taken. Also, is there a better approach that Japan could have taken?
- vidarh 8y ago
- Haga 8y agoMy own little pet theory is that super volcanoes are made by nature's corium, slowly desolving from bedrock and migrating in channels to earth's core.