A recent news release from a Japanese power utility has generated a number of headlines across the Western media about “soaring radiation levels in Fukushima.” That would be frightening news if true, but it turns out that saying radiation levels are suddenly spiking in Fukushima isn't entirely accurate.
TEPCO is the nationalized electric utility that operated the Fukushima Daiichi nuclear power plant. On January 31, TEPCO issued a news release and information package that described the successful efforts to send a robot beneath the primary containment vessel of Unit 2. Unit 2 was one of three reactors at Fukushima Daiichi that experienced a meltdown in March 2011, following a massive earthquake and subsequent tsunami wave that knocked out power to the complex (a timeline of the disaster can be found here).
Little is known about what happened to the reactor fuel assemblies following the nuclear accidents. It has been theorized that fuel assemblies in all three reactors melted through the reactor containment vessels and onto the concrete pedestal of the primary containment building.
However, radiation levels are so high that it has been impossible to use existing technology to explore the highly radioactive zone where the molten fuel assemblies are thought to remain. A sensor was briefly inserted into the Unit 2 containment vessel in 2012 and detected 73 sieverts, but radiation at that level quickly disables the electronics of any robotic device sent in to investigate.
It has taken TEPCO since 2012 to develop new technologies that can withstand the radiation. So, TEPCO's January 31 news release marked something of a milestone in the quest to decommission the Fukushima nuclear reactors because it represented the first time the radiation in the highly radioactive area below a reactor had been accurately measured.
Radiation levels taken out of context
However, much media coverage failed to frame stories around that context and instead focused on the high radiation levels measured near the pedestal of the Unit 2 reactor complex.
According to a PDF handout from TEPCO, radiation levels at one location in Unit 2 measured 530 sieverts. A sievert is a unit measurement for a dose of radiation absorbed over time. One sievert will cause illness if absorbed all at once; eight sieverts will result in death, even with treatment. A dose of 530 sieverts, totally unexpected by the robot's designers, would likely cause instant death and would disable a robot after a couple of hours.
The same probe measured a lower radiation reading of 20 sieverts in an adjacent space, but Western media attention zeroed in on the 530 sieverts number. Moreover, several news outlets characterized the findings as indicating that radiation levels are “soaring” at the Fukushima plant — despite this being the first time that technology has been able to accurately measure radiation in that area of Unit 2, and despite some evidence showing that radiation levels are generally falling in the area surrounding the Fukushima nuclear plant itself.
The Guardian newspaper's headline read, “Fukushima nuclear reactor radiation at highest level since 2011 meltdown“, while popular science blog Gizmodo noted, “Radiation Levels Are Soaring Inside the Damaged Fukushima Nuclear Power Plant.” While both publications were not the first to break the story in the English-language media, both are identified by Google News as being “highly cited”, and may have influenced how other news organizations reported on the Fukushima radiation readings.
The Guardian story was shared on social media. Many of the tweets, such as the one below, discussed the high levels of radiation observed at Fukushima, while disregarding the context where and how the readings were made.
IT'S NEVER GOING AWAY…#FUKUSHIMA Nuclear Reactor Radiation at Highest Level Since 2011 Meltdown…#Environment https://t.co/Zn7KuATWz3
— Selina (@selinasorrels) February 8, 2017
US commentators put an American spin on Fukushima news
By February 8, the story was gaining steam, with rumours of another environmental calamity coming while the media looked the other way. US-based outlets such as InfoWars, the influential website devoted to conspiracy theories, and the more mainstream Fox News had picked up the story of “unimaginable” levels of radiation at the Fukushima nuclear power facility. The Fox News story quoted Adam Housley, a journalist who had covered the nuclear accident in 2011, as saying, “To put this in very simple terms. Four sieverts can kill a handful of people.”
Housley did not try to put the source of the high radiation levels in context, and instead sent out this tweet:
This report…should concern all of us and nobody is talking about it https://t.co/s12l6A36yZ
— Adam Housley (@adamhousley) February 8, 2017
The Fox News story was quickly re-tweeted by Joe Walsh, a far-right pundit and talk radio host, who provided a partisan spin to the story:
Meanwhile, the Leftist media is busy talking about Trump tweeting #EasyD.
— Joe Walsh (@WalshFreedom) February 8, 2017
The story of radiation levels in Fukushima continued to be viewed through a partisan lens. Lou Dobbs, who hosts a program on Fox Business Network, also suggested the “mainstream media” was ignoring another potential disaster. A follower then, in a reply that was favorited and retweeted dozens of times, linked the perceived disinterest in the story by the media with attacks on US President Donald Trump and global warming:
@LouDobbs @CNET @POTUS Yes. Media ignores this. But SCREAMS at Trump for not believing in #GlobalWarming
— ELwhyEssAyy (@elwhyessayy) February 7, 2017
Adding more disinformation to the Internet echo chamber
While some of the conversations online focused on a supposed impending calamity from the high radiation readings in Fukushima, others injected wrong information into the mix.
Global Research, a Canada-based website that has been accused of spreading conspiracy theories, tweeted a misleading image to accompany its story on the high radiation levels at Fukushima Daiichi. The photograph shows a massive fire at the Cosmo petrochemical plant in Ichihara, Chiba in 2011. While the fire was caused by the massive 2011 earthquake, it has nothing to do with the Fukushima nuclear disaster:
New Radiation Level at Fukushima Dwarfs the Highest Peak at Chernobyl https://t.co/SgdSRfFl1G pic.twitter.com/MOmj1OPuA1
— Global Research (@CRG_CRM) February 7, 2017
Others used the increased interest in radiation levels at Fukushima to share highly misleading images that have circulated online ever since the disaster occurred in 2011. For example, Twitter user @MikeMtk63 included a map created in 2012 by environmental consultancy ASR:
#RADIATION ALERT: Tests at tsunami-hit #Fukushima nuclear plant reveal ‘unimaginable’ levels https://t.co/YuliSCOJxZ pic.twitter.com/TpfbrNsply
— Mike Brosnahan (@MikeMtk63) February 5, 2017
ASR's map has been shared hundreds of times over the past six years, but always out of context. In its explanation of the map, ASR says (in all caps), “THIS IS NOT A REPRESENTATION OF THE RADIOACTIVE PLUME CONCENTRATION.” Instead, ASR says the map is intended to illustrate where free floating material (fish larvae, algae, phytoplankton, zooplankton, etc.) present in the sea water near the damaged Fukushima Daiichi nuclear power station plant would have dispersed to in the days following the earthquake on March 11, 2011.
Another Twitter user tweeted a financial news blog Zero Hedge story that featured another widely shared image that supposedly shows radioactive contamination of the Pacific Ocean from the Fukushima disaster:
Fukushima Radiation Has Contaminated The Entire Pacific Ocean (And It's Going To Get Worse): https://t.co/VgKouDe6y2
— trutherbotgold (@trutherbotgold) February 5, 2017
The image is in fact from the US National Oceanic and Atmospheric Administration (NOAA), and is intended to represent tsunami and wave activity all across the Pacific Ocean following the March 11, 2011 megaquake that struck Japan. Once again, the image has nothing to do with the Fukushima nuclear accident.
‘No, radiation levels at Fukushima Daiichi are not rising’
SafeCast, a volunteer-driven grassroots organization that collects environmental data, noticed the news stories about a sudden spike in radiation levels at Fukushima. In a blog post called “No, Radiation Levels at Fukushima Daiichi Are Not Rising,” SafeCast pointed out the reason why the radiation levels measured in late January were so high was because it was the first time the area had been explored since the accident:
It must be stressed that radiation in this area has not been measured before, and it was expected to be extremely high. While 530 Sv/hr is the highest measured so far at Fukushima Daiichi, it does not mean that levels there are rising, but that a previously unmeasurable high-radiation area has finally been measured.
SafeCast got its start in 2011 in the weeks and months following the Fukushima nuclear disaster, when no one was really sure just how much radioactive contamination was occurring. While volunteers monitored and posted readings from all over Japan, since 2011 the initiative has since gone global.
The organization also stated that, according to its sensor network, radiation levels near Daiichi appear to be steadily declining. However, SafeCast says the main lesson from the January exploration of the reactor pedestal is:
The process of removing melted fuel debris from the damaged reactors at Fukushima Daiichi is expected to take decades, and these recent findings remind us once again that TEPCO has little grounds for optimism about the challenges of this massive and technically unprecedented project.
yo pompous fat man.
people aren’t as stupid as you think
no one except for a stupid fat ass like you think that the radiation is rising.
it has been this high or HIGHER since the day it melted down 5 years ago..
It would be me coming over to your house to fix your scale, and discover that you miscalibrated it for 5 years.. your weight didn’t soar.. but it doesn’t change the fact that you have been a fat partisan fool for 5 years.
Thank you anonymous internet user! Your comments mean a lot to me.
Pompous, stupid? I suggest looking in the mirror.
Did you even read or glance at the pdf report linked in the article?
Look at the last page.
3 points of measurement (note the measurement are estimates), and all three are INSIDE the containment vessel:
1. 30 Sv/h
2. 530 Sv/h
3. 20 Sv/h
I would have thought that where the control rods are (closest to the fuel source), the readings would have been the highest, but it is the lowest at 20 Sv/h.
Any thoughts why?
I have no idea, except to suggest that some of the molten corium became affixed to the metal grating, and the robot encountered that hot spot. The other corium melted through the grating and is someplace below, maybe underwater (water blocks radiation to some extent). No idea, though.
Not necessarily. Water would actually speed up reaction. This might actually account for spikes in radiation levels if those occurred–water coming in contact with melted down core. But since I can make little sense of the actual data out there in the media. I’m just talking about a hypothetical.
That doesn’t make sense, you do realize, yes? You mean the core? They still haven’t had a view of the cores since 2011. The sites are too radioactive, the cores of 1, 3, and 4 are expected to have melted through their containment vessels. The spent-fuel rods, if exposed to air, will catch fire; this is why the roofs of 1, 3, and 4 blew off; they had a neutron explosion. The amount of ionizing radioisotopes in the air will knock the electrons in the robotic circuitry out of whack: robots can’t help us. If another, AND THIS ISN’T NARROW IF, if this happens again, Japan is fucked. You are the same stupid people who like to say statistics, “the chances of getting hit by lightning are…” Lightning just struck Japan, and they are on a fault line, good chance of it getting struck again. If you’re so tested, you do realize that Sieverts are simply a measurement of ABSORBED radiation. Becquerels are a measurement of EMITTED radiation–basically, a measurement of how many ionizing events are taking place per sec, per min, per kilogram, etc. If you really are going to trust TEPCO, being proven pathological liars, then go right ahead my friend. I’m pretty sure the Japanese government has classified many documents they don’t want to be disclosed to the public–this is substantiated because they have declassified a lot of information.
For more than 50 years I have been against nuclear energy power plants, especially in a country like Japan, where I have lived for the last 23 years, because Japan has a long history of both powerful earthquakes and tsunami. The Fukushima nuclear disaster happened because of bad plant safety design, a powerful earthquake and monster tsunami. It was a man made nuclear disaster
It’s important that all stories about the Fukushima nuclear disaster are reported with accurate and checked facts because it serves no one to serve mistruths or sensationalize headlines just for increased story clicks.
The 530 Sieverts measured inside the No2 reactor is not “soaring radiation” but an the first accurate reading since 2011. Also the level is inside the reactor with melted fuels and I would expect the same in reactors 1&3.
The radiation levels at the nuclear plant and the surrounding Fukushima have actually lowered since 2011. The levels in the ocean have also fallen. There are still many concerns, and will last for the many decades it will take to deal with the disaster at ever increasing costs. There are times when the truth is not reported like making areas safe for former residents to return.
For five years I posted about the disaster but stopped just because of dealing with so many crazy stories and mistruths.
Thanks for your comments. Do you have a link to your blog? I have lived in three nuclear towns in Japan: Shika, Tokaimura and Tsuruga. I’ve lived in Tsuruga since 1995. Fukushima is a complicated subject. Like you said, in some ways the situation is improving. What I’d really like to know more about is cesium contamination in the highlands northwest of Tokyo. Not much reported on that. Or what happened to the contaminated sediments collected from storm drains around Tokyo. Where did it all go?
Sorry I closed down my blog and the many other sitesI posted to also closed down or moved on. I made many posts on Japantoday but I don’t post anything anymore.
The contamination in the mountains north of Tokyo was a small area and was cleaned. I have no new info on that. The collected sediments were incinerated. The background radiation levels in Tokyo are less than those in New York City.
The mountain areas in Fukushima will remain a problem for years to come. I was of the belief that too much public money has been wasted trying to decontaminate areas inside Fukushima when the majority don’t even want to return. The 30 km area from the nuclear plant should have been closed until the nuclear disaster is over in 100 years.
Of concern is the new secrets security laws and the general lack of articles in the Japanese media. Something of overload, I suppose. This disaster will take more than 100 years and will cost more than ¥50 trillion, something I stated in 2011, much to the disbelieve of some.
I live in Kobe City with the power supplied by Kansai Power Co with its reactors in Fukui. With the new power supply laws maybe I will change my power company to a renewable energy one.
I don’t think the Fukui Kansai Denryoku reactors are coming back online any time soon. Mihama is to be decommissioned; Oi has been blocked from restarting due to a court ruling on a lawsuit initiated by citizens groups in Kansai and Shiga; Takahama sits atop a fault line.
I am not entirely sure the sediments from Kanto were incinerated. When I last checked, they had been shipped to Akita or Aomori by train, and the train was turned back. Did the various Tokyo municipalities then incinerate them?
I also do recall seeing a map of the highlands northwest of Tokyo, as well as Gunma. Some pretty serious contamination. There is some in the western Niigata highlands bordering Fukushima as well, I think.
Maybe I’ll write an article on that next, to clear it all up.
“I don’t think the Fukui Kansai Denryoku reactors are coming back online any time soon. “
Yes, probably true but also remember that the nine mainland power companies are some of the most powerful in Japan and have made huge donations to the LDP government party for decades. Certainly, since the disaster the nuclear industry is down but not quite out. When all the 48 reactors were shut down following the nuclear disaster it seemed that would be the end of it.
Currently, the position is no longer so clear and we could eventually see about 20 reactors going back on line including some of those owned by Kansai Power. Eventually, probably we will see nuclear power end by default when old plants close and no new ones are built but plants are being given licenses to extend their 40 year cycles.The Kansai Power No3 Mihama reactor was given an extension which will cost ¥165 billion to update and will take until 2020 to complete. The No1&2 Takahama reactors were also approved for life cucle extensions.
There was some hope to see a greater drive with renewable energy but that is faltering even with some cutbacks.
For contamination disposal check out the Citizens’ Nuclear Information Center
“I am not entirely sure the sediments from Kanto were incinerated.”
I don’t know about Kanto which includes quite a few Prefectures but I did read about Tokyo contamination being incinerated?
Yes I do seem to recall now that some municipalities in Tokyo did incinerate the waste. Thanks for the link to CNIC.
Thanks for the info about Mihama as well. The general consensus in Tsuruga (which supplies workers etc to the Mihama plant) is that it’s never coming back online. I think, after Tsuruga, Mihama is the oldest power plant in Japan (maybe the Oarai plant is, can’t remember).
Thanks for clearing this up. The new measurements are incredibly frightening, but as you point out, it isn’t “rising” – it’s probably been like that ever since 2011, inside that mess in Fukushima Daiichi. Media tends towards alarmist headlines because it sells newspapers and gets clicks. Fortunately the Japanese media have been more balanced about this; none have reported the radiation as “rising”.
Thanks for your comments, and thanks for reading the piece.
Soaring implies that it has suddenly risen to super dangerous levels.
That highly unlikey, it probably has been at super dangerous levels all along just they were blissfully ignorant the whole time.
My take is that the articles claiming it is soaring are sensationalist.
And this article is trying to downplay the fact that its worse than they imagined all along and have little idea about how to proceed since the radiation kills all their equipment in a few hours.
Thanks for your comment. I would encourage you to read the entire article. You may find the final paragraph interesting.
Thanks, I did read the entire article, and I shouldn’t have said that you downplayed it. I do agree with the final paragraph; they are relying on developing new technology to meet unprecedented challenges that they have never met before and don’t have a real clue as to how long it will take.
The fact is they never designed the reactors to be recoverable from this large a catastrophe. They never believed it could happen to them.
Thanks for this. It’s a tricky subject to write about, because opinions are so polarized. There are some who think Fukushima is a catastrophe that is threatening the planet. There are other who think “no big deal.” But as you mentioned the reality is that this is an enormous cleanup job.
On the other hand, Fukushima, by it’s very nature, takes attention away from the tens of thousands of people who have been left essentially homeless by the tsunami (and, in Futaba-cho, the nuclear disaster).
If they, the BWR designers, never believed it could happen, neighbours of the FD1 site were remarkably fortunate that that very thick-walled primary containment building, and the almost as thick-walled secondary one around it — diagram at http://www.analys.se/engelska/publications/fukushima-the-first-observations-inside-reactor-2/ — were built just for the hell of it.
Actually it must have been at least a thousand times higher immediately after the earthquake forced the shutdown.
It hasn’t gone up, and the high levels are not an issue because they are inside containment. It’s actually fairly simple and not at all surprising or dangerous, but of course that wouldn’t serve the thirst for dramatic stories.
For many, Japan and Fukushima remain far away for now! But for news hounds it is ever present. The complexities deepen when one tries to take into account the Japanese political landscape which is vastly different from our own, and the culture and spirit of it’s people as regards all things Nuclear, which is complex for obvious reason. I wonder what would happen if Humanity was told it had ’10 years’? And our vast collective unconscious drew a collective scream and raved into the long goodnight? Is it a fitting end for hustling Lucifer Droppers such as we? Now I too am become Death and the destroyer of worlds? No! I would hope that humanity would finaly rise in true unity and make humble offerings to Fukushima, for in all our Wars we’ve never managed to kill an entire Ocean before…each of her billions upon billions of endless soldiers just One Ten Thousandth of One Millionth of a Metre in diameter!
I would love to know who said the radiation levels were “unimaginable”. And, indeed, whether they actually said that about radiation levels right next to a nuclear reactor vessel, or about something completely different.
Indeed. I tried tracking down the source of the quote.
That said, I’m not sure if 520 sieverts is typical of a working reactor core. It’s possible the corium created a more highly-radioactive isotope, much like the “elephant’s foot” of Chernobyl.
In fact the fuel neither here nor at Chernobyl is more highly radioactive – just more exposed, with breaking the fuel pins and the reactor vessel.
Yes, I get that it’s more exposed, but it seems to me there is some complex chemistry going on that *may* result in radioactive hot spots. How many sieverts would an intact (and exposed) fuel rod emit?
The Wikipedia page on the Chernobyl corium is pretty interesting: https://en.wikipedia.org/wiki/Corium_(nuclear_reactor)#Chernobyl_accident
I guess it’s possible the fission products might separate by physical properties (solubility/density etc) to produce some hotspots. Overall there isn’t any extra radioactivity though. Note that the fuel rod sheath is a pretty effective barrier.
>Note that the fuel rod sheath is a pretty effective barrier.
But it’s all a melted mess now, right?
Exactly. That’s why you can get higher readings – not because there’s more radioactivity, but because there’s less shielding.
Rems-per-hour data (for a fuel assembly, a bundle of rods, not just one) you can get from LLNL report “Dose Rate Estimates from Irradiated Light-Water-Reactor Fuel Assemblies in Air”. To convert them to sieverts, divide by 100.
Until they verify where the melted down cores and stored rods are (I mean what wasn’t blown out the top, something that they don’t even want to admit to, but which seems quite possible in the case of reactor 3), that is all you are going to get is lots of speculation–on both sides, the anti-nuclear people and the pro-nuclear. The reality is, you can’t recover and clean up what you can’t find. And the complex leaks huge amounts of radioactive material into the groundwater and out to sea.
Easy point first: the impermeable seawall was completed in October 2015, so the much-talked of groundwater seepage into the ocean stopped then. “tepco completes seawall” should find a report.
Next: unit 3, which did not blow anything out of the top. Here is a picture from 2014, courtesy of the now-dormant ex-skf blog, article http://ex-skf.blogspot.ca/2014/09/video-showing-fukushima-i-npp-reactor-3.html
In the middle there you can see a circular region with three slabs of concrete across it. Those are across the top of the containment vessel and under the containment vessel cap is the reactor vessel, but in fact below those slab are another three slabs running at right angle to the ones you can see. If there had been an explosion out of the top of the reactor, those slabs would be broken and flung aside.AS you can see, they are in place. The middle one is slightly damaged, but in a way that suggests something fell on it from above.
I have my doubts. It’s often more like Tepco does busy-work to make it look like they are cleaning up. My understanding is that they have not solved the problem of water going in, out, through the complex. Nor have they accounted for the 600 tons or so of missing fuel and corium.
The bad news would be what is reported in this Scientific American article.
How did you arrive at that faulty understanding about the water? The corium is known to be in containment, so you may have a faulty understanding there too.
The seawall addresses the seepage of groundwater from the site into the ocean. It runs across the seafront directly in front of the reactor buildings 1-4. The most contaminated water is in the turbne buildnig basements, which is extractly directly and separately.
How did you arrive at the faulty understanding that the corium is known to be in containment? It’s like you are in a different universe Joffan. Show me a source that says they have verified the three melted down cores are in containment, or I am going to find out who you are, and have you committed.
Corium is in containment because of this little thing called physics.
If it isn’t contained, it isn’t contained. Even your pathetic troll ass can’t change that.
That is a little thing called hydrology!
I cited a Tepco source. I guess that is how I arrived at the ‘faulty understanding’.
You cited a mid-2014 press release that describes some of the things they were going to do, which they have now done.
Which haven’t worked. Except for troll assholes like you.
Engineers still have to locate the molten fuel, which seems to have melted through steel vessels. It remains so radioactive that no humans can enter the reactor buildings. Tepco has “no idea where and how much fuel debris is in the reactor now,” says nuclear engineer Tadahiro Katsuta of Meiji University.
Therefore, saying it is in primary containment is meaningless if that containment no longer CONTAINS, but LEAKS.
Now, if 100 tons of groundwater flow into the complex every day, where does that groundwater go?
The three damaged reactors still need to be cooled with water to keep their melted cores from overheating. The water picks up radiation and leaks out through cracks and other damage from the disaster. The water flows to the basements, where it mixes with groundwater, swelling the volume of contaminated water.
TEPCO has cut groundwater infiltration to 150 tons per day, nearly one-third of the amount two years ago, mainly by pumping out groundwater upstream and directing it to the ocean. The utility hopes the underground ice barrier will eliminate all groundwater inflow.
Japan struggles in cleanup of Fukushima meltdown
Japan struggles in cleanup of Fukushima meltdown
Radioactive water continues to leak into the ocean, but at a far lesser rate than it did early in the disaster. Ocean radiation levels are about a thousandth of what they were soon after the accident, according to Ken Buesseler, a radiochemist with Woods Hole Oceanographic Institution (WHOI) who has monitored the area. Because of concerns about the health of marine life, commercial fishing is still banned in waters just off the plant.
It gets pumped up and processed. That is in fact exactly where that value comes from.
Show me the documentation that they have pumped up and processed that many tons of water. They keep saying they are storing it all. Which is more likely a joke that they use to impress fools.
100? 150? Maybe it’s really 200? Or 201? Or 400? How the f- would you know asshole?
The good news would be what is reported in this article.
Please do not call people trolls, Charles. There is no reason here and it is unpleasant.
He doesn’t even use a real name. He is a TROLL. And I have been called that so many times, it feels good to use it on a real one.
This isn’t really so much an article about what is actually going on at the Fukushima site, but really more about how bad much of the coverage is that is out there on the internet. Two very different issues Nevin. Are radiation levels soaring? Might depend on where you stick your sensor.
I can only rely on a variety of sources, including Safecast and IAEA,among others.
But your story is more about what others made of info. from Tepco. The only story here is, readings are soaring because we are sticking our sensors in new dark holes.
Joffan is one of those pro-nuclear power trolls who shows up at every one of these discussions and cites ‘science’ and ‘physics’, etc. He is a troll asshole.
This might be one of the stories that got the ‘soaring’ trend started. It’s an AP article, and I’m just citing one aggregator of it. It’s mostly based on info. from Tepco, which I always take with a grain of plutonium salt or two.
Kimoto said the noise-based radiation analysis of the Unit 2’s condition showed a spike in radioactivity along a connecting bridge used to slide control rods in and out, a sign of a nearby source of high radioactivity, while levels were much lower in areas underneath the core, the opposite of what would normally be the case. He said the results are puzzling and require further analysis.
TEPCO officials said that despite the dangerously high figures, radiation is not leaking outside of the reactor.
Read more at: https://phys.org/news/2017-02-cleaner-robot-fukushima-reactor-due.html#jCp
But now that I look I see much of the ‘furor’ largely derives from a Kyodo English-language article, like this aggregated at Mainichi.
Radiation level at Fukushima reactor highest since 2011 disaster; grating hole found
February 2, 2017 (Mainichi Japan)