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Six Years After Fukushima, Robots Finally Find Reactors’ Melted Uranium Fuel (nytimes.com)
402 points by htiek 12 months ago | hide | past | web | favorite | 179 comments

> https://youtu.be/c5hQ6WlioRE

This has to be the worst possible way of sharing information; a video of 2 still images and a computer voice reading a text.

Right up there with images inside a word document, inside an email.

YouTube really should be detecting and pushing them to the bottom of search results. Downvoting doesn't appear to have much of an effect.

I believe likes and dislikes on Youtube both count as "interaction" as far as rankings are concerned.

Won't matter much in this case as it's heavily linked to by all kinds of news outlets.

No it shouldn't. Sometimes videos like this one are a source of unique information.

I've seen a few of those before.

Some were CC text from CNN articles with random "war pictures". It was surreal - like a badly done brainwashing video. It had the eerie qualities of belonging as perverse art exhibit.

I have also seen these in "alt"/neonazi/kkk politics channels. There's not much worse than showing pictures of the KKK and black people while a robotic voice throws curse words and racial epithets. There isn't much else to say other than "WAT?"

I think you're lucky a fax was not involved.

"At Chernobyl, the Soviets simply entombed the charred reactor in concrete after the deadly 1986 accident. But Japan has pledged to dismantle the Fukushima plant and decontaminate the surrounding countryside, which was home to about 160,000 people who were evacuated after accident."

How much of this decision is simply about space? Russia is the largest country by area, with 21 people per square mile, while Japan is much smaller, with 873 people per square mile. If you compare GDP/area the difference is even greater.

Chernobyl is still in Ukrane (near the boarder with Belarus) and not Russia (yet). At the time it was part of the Soviet Union, but Ukraine has always been a bread basket of Central Europe.

Fundamentally, Chernobyl is a much larger (order of magnitude) event with 6 tons of radioactive material burned and released. Frankly, for all the coverage Fukushima gets, it's amazing that you rarely hear about the associated tsunami and the damage it caused... 22k direct casualties with 2.5k still missing, 230k people still displaced in 2015 with ~400k structures destroyed.

> 230k people still displaced in 2015

The displacement is mostly due to radioactive contamination still being high in several zones around Fukushima.

The tsunami was a huge catastrophe but it's over. There is no breaking news to get coverage.

Fukushima on the other hand is an ongoing disaster producing news from time to time which, naturally, get coverage.

No, they are separate. Only 100k people are still displaced by Fukushima covering an area of over 400km2.


Sendai is some 50km away from Fukushima and the population center is well outside the evacuation area. Tamura and Minamisoma are the only cities within it.

The tsunami destroyed 400k structures and decimated Sendai, which (note that the figures in the linked article are in 10s of people and structures as indicated at the top of the figures). Some 300k people and 100k homes were within the inundation, ~25% of the local population.


In the Fukushima evacuation area the majority of the surface is less than 4x background radition ~1uSv/hr. In discussing an ongoing disaster please look at this video:




"yet" +++

This badly understates the Chernobyl response. They did remove the heavily contaminated surface soil from the immediate vicinity and clean up the rest of the site so they could continue to operate the remaining reactors. They built the Shelter Object ("sarcophagus"), instead of just pouring concrete all over the site, so that they could continue to monitor and inspect. And earlier this year, they at last covered the Shelter Object with the long-delayed New Safe Confinement, which includes cranes and other robotics intended to dismantle and decontaminate both the Shelter and the ruins of the reactor.

It's certainly true that the Soviets, and after them Belarus and Ukraine, did/do use the "just leave it alone" strategy for part of their Chernobyl response. But it's by no means the whole story.

The scale of the New Safe Confinement is stunning. Here’s a 2min video of it being moved into place: https://www.youtube.com/watch?v=n7aMcKinrWY

Thank you for sharing this. I had read about it when they were still building it and marvelled at the scale and ambition of the project. That structure is so large it apparently has its own weather system inside.

You can also marvel at it from satellite photos:


I'm possibly nitpicking here, but Chernobyl is not in Russia.

Not but it was in the USSR at the time which many people incorrectly equate with Russia today. To me it's almost ok to say "Russia" when talking about things back then. So long as you don't say Chernobyl is in Russia today.

For you it might be ok but for us who lived in the USSR it is an insult. Just a heads up, you can get into a bar fight anywhere in Eastern Europe referring to these countries as Russia.

Ukraine and Russia were practically in a shooting war a few years ago. It's about as "ok" as walking around your Californian office calling people "Confederates"... if the civil war happened in 2014.

Don't insult people with ignorance.

Eh... your example is pretty far from reality, especially considering California was never part of the CSA. Ukraine was part of the USSR, and was part of the USSR when the meltdown happened.

If you want a better analogy, it's like referring to Massachusetts as England when discussing colonial America. Semi-accurate at the time, main difference being Massachusetts was part of the British Empire along with England, but was not actually owned by England itself. The fact that there was a long and bloody war that followed between the two doesn't change that mostly-accurate history.

Yes, Ukraine wasn't part of Russia. But it was part of the USSR, which split into several countries, the most powerful and influential of them being Russia. It's a colloquialism just as much as it is an inaccurate statement.

Apropos England, you'd better not go to Scotland and refer to it as "England" either... people will be justifiably mad at you. And those two countries are currently united.

This one is also an exaggregation. Russian government supported anti-government forces in East Ukraine, so they could fight against their own enemy. Russian profit in it is destabilized buffer between RF and NATO expansion (driven by purely military ambitions of the force external to conflict). I had few discussions with eastern ukrainians. All of them hate western Ukraine (mutually ofc) and said it was always like that. Absolute evil-izing of russians is a big mass-media program in Ukraine, not the other way round. It is not very succesful though, because both nations are heavily mixed.

I’m not appreciating the situation, but let’s not fall into Evil Axis delusions.

You're probably not Ukrainian, then. Or Belarussian or Georgian or Lithuanian or Latvian or...

It's almost like people from different countries have different names for other nations. Language is weird like that.

160k is around 0.15% of Japan's population, and there's plenty of space for them to move to since the countryside is rapidly depopulating. Of course, it's not quite that easy to forcibly migrate people in practice...

You gonna move their jobs as well? There is a reason why they were living at the area at the first place.

Moving jobs to the countryside does not sound like a bad idea TBF. I want to move to a small town and be able to take a bike to work (and I prefer a workplace, remote working doesn't work for me), but all of the employers are in the big city so I'm forced to sit in traffic for over an hour both ways every day.

Does anyone know how they extract the molten fuel? Sounds like they will use more robots, but if it's taken this long just to get a robot to see the target, how on earth does a robot retrieve this stuff? Must be a career defining experience for these robotists, doing something that can really help an awful situation

That's basically what they say at the end of the article:

“I’ve been a robotic engineer for 30 years, and we’ve never faced anything as hard as this,” said Shinji Kawatsuma, director of research and development at the center. “This is a divine mission for Japan’s robot engineers.”

> This is a divine mission for Japan’s robot engineers

That is so cool. I'd love to see some kind of "lessons learned" summary from the robotics people.

I saw a good documentary on NHK about the effort to enlist high schoolers and college students who might be able to think outside the box regarding this mission. My impression is that, no matter what happens in Fukushima, Japan is going to have a deep bench of robotics engineers in the coming decades.

Unfortunately, I'd imagine the vast majority of the helpful information learned will be kept a proprietary secret.

I could imagine that shielding electronics from radiation could fall under military secret.

These days, once you get to the level where you can afford to develop them in the first place, there really isn't that much of a difference.

Is that all that secret though? Can't you buy radiation-hardened versions of chips if you want to?

The article says they’ve built a $100 million research center for the purpose of building radiation hardened robots for this environment.

I’m sure as they learn techniques and technology for building these robots it will progress quicker. A small robot with a camera is the first step.

They don't have the slightest idea. It's an absolute miracle that they just managed to get a picture of the molten core after 6 years. Now probably they can start to think what to do, but my guess is that they don't have any idea at the moment.

I long believed that nuclear power was the only energy source cleaner than fossil fuels and scalable enough to meet the energy demands of the world. While that might still be true in some sense, I now believe that humanity isn't ready for nuclear power.

Besides the Fukushima and Chernobyl type issues with organizations skimping on design, there's still an outstanding problem of nuclear waste storage. The current nuclear power statistics haven't factored in a major waste storage incident because one hasn't happened yet. Until we've witnessed multiple lifecycles of nuclear fuel consumption to full waste breakdown, the safety stats could still swing against nuclear power. Maybe all it'd take is a terrorist incident involving nuclear waste. From what I understand, breeder reactors can vastly reduce the quantity of a power plant's waste and produce waste with a much shorter half life. This isn't widely implemented or shared because that technology can also be used to produce weapons grade material. I think humanity will be ready if/when we can sort out our differences without violence and greed/corruption are no longer problems for most large orgs.

Additionally, renewables seem to have better scalability today than they did in the 90's when I formed my initial opinions. Right now, the worst case situation with a renewable power source is probably a large dam bursting. That's certainly possible due to corruption or terrorism too. If the three gorges dam suddenly burst, that could take out most of Shanghai. For most other renewables, the potential worst case is much milder though.

> Maybe all it'd take is a terrorist incident involving nuclear waste.

There are so many radiologic sources out there, used for many purposes (medicine, gammagraphy), very dangerous[1] but taken with much less care than nuclear wastes from the nuclear power industry. Stuff like this [2] happen all the time …

[1] https://en.wikipedia.org/wiki/Goi%C3%A2nia_accident [2] (in French) https://www.asn.fr/Controler/Actualites-du-controle/Avis-d-i...

Or whatever happened in Russia within the past few weeks: https://www.theguardian.com/world/2017/nov/10/nuclear-accide...

I kinda agree with your point: terrorists already have considerable access, theoretically, to radioactive materials. In fact, the materials used for medicine and science are in many ways much more dangerous from a public health perspective given their short, energetic half-lives.

The only substantial, long-term danger from terrorists is to the financial viability of nuclear power. Nobody cares about incidents like the above. But if it were tied to terrorism somehow it would be all over the news and nuclear stocks would plummet. Similarly, for a terrorist incident involving medical use even anti-nuclear activists would have more nuanced reactions, whereas if it involved nuclear power such an incident would herald the end of the world.

Nuclear facilities aren't really dependent on market perception to keep their stock prices high - they sell power.

The terrorists won't do a better job of slandering fission than the oil & gas companies have done, and nuclear facilities and fuel storage make horrible terrorist targets. The facilities are explosion hardened by design, and spent fuel is essentially rocks. It would take a lot of work and explosives to make a weak, uninteresting, highly traceable, not too dangerous "dirty bomb". That requires supplies generally unavailable to terrorist cells, much less cells inside a nuclear nation. It also requires hazardous materials training and technical skills generally unavailable to terrorist organizations, much less embedded in a target area.

As has been the case for decades: the largest genuine threat from an action like that would be panic, and overreaction, from a riled up and ignorant population.

I agree that renewables are a very good alternative to nuclear power, but in practice moving away from nuclear means doubling down on coal. The problems with nuclear are political, but the alternatives to nuclear power are mired in political conflict as well.

As for your dam bursting scenario, something like that actually happened in the 70s when the Banqiao Dam burst. Nearly 200.000 people died. Fukushima had 0 radiation deaths.

You can't really say 0 deaths, because no one knows. We don't have good epidemiological models for wide-spread low-level dispersal such as was seen at Fukushima, we already know incidences of cancer and gene mutation don't scale linearly with exposure at low levels. There are also associated deaths from psychological factors of those who were evacuated, lost land / business etc. which will only become apparent in years to come.

Dams do have the potential for massive loss of life as you say, and they also suffer from the problem of massive centralisation of capacity (unlike e.g. solar or wind). On the smaller upside, the models related to fatalities are pretty well understood.

Perhaps an instant move away from nuclear may need coal, although here in the UK it's gas that has been taking up the slack while the government dilly-dally on whether to build out new nuclear or invest in renewables research (successfully doing neither).

I see over the longer term renewables coming up as nuclear is naturally retired at the end of the current plant's lifespan. Solar is now cheaper than coal to built-out in many places, there are other impediments but (generally) lack of public support isn't one of them (compared to coal/nuclear).

Deaths resulting from psychological factors involving those who were evacuated count when it comes to nuclear energy but not when it comes to dam failures? I don't think this kind of double standard is reasonable.

Besides, I'm pretty sure you just copied the argument about low level exposure from the Fukushima disaster wikipedia page, but you conveniently left out the next sentence: "given the uncertain health effects of low-dose radiation, cancer deaths cannot be ruled out.[11] However, no discernible increase in the rate of cancer deaths is expected."

Scare-mongering about nuclear radiation doesn't help anybody but the coal and gas industry.

I never said that such deaths form dam failures didn't count. The only reference I made to dams is that the model (physically traumatic & psych-related death) is well understood. Deaths due to low-level, widely dispersed radiation is not.

I'm afraid you were wrong to be "pretty sure" that I copied the argument from Wikipedia, I haven't read that page (until you pointed it out now). My comment comes from what I've picked up working for 10 years in epidemiology at Oxford. I didn't "conveniently" leave out the next sentence, and I wouldn't have quoted it anyway as its effectively tosh. There is no discernible increase expected on current models, but the current models are accepted (by most experts) not be useful predictors, as described in my initial post.

It's not "scare-mongering", it's being open to scientific discussion and exploration. Blind-adherence to your view-point doesn't help anyone but the nuclear industry.

Let's have open and honest debate. Even when that means we say "we don't know".

> Fukushima had 0 radiation deaths.

I think making that statement or even the comparison to other types of disasters is a little disingenuous. With most disasters they happen and then they're over in very short order. A nuclear disaster is very slow to unfold and the deaths from radiation related illnesses are not yet fully realized for quite some time.

The Chernobyl disaster is still unfolding and even with the latest containment, NSC, having been installed. It will take hundreds of years before we're done with it.

> in practice moving away from nuclear means doubling down on coal

Is it not possible for us to build out renewable energy on a large scale? My impression was that we're reaching points where it's very cost effective to do so.

An accident with spent fuel rods / nuclear waste will happen in our lifetimes, and probably in the US; the US does not have proper nuclear waste disposal because nobody wants to host it. Earlier they'd just dump it in the ocean, but now, it's stashed in the nuclear plants' spent fuel rod basins, waiting (for decades now) for the country to build a proper disposal facility. IIRC the last one was a huge project inside a mountain somewhere.

Isn't there also the issue of fuel-reserves (uranium etc.) actually not lasting more than about 50-100 years?

Yeah, that's an issue too, though again, breeder reactors could extend that number significantly. But the countries that possess that tech don't want to use it widely or share it. Not sure if the former is due to cost or lack of expertise. The latter is definitely due to distrust in humanity.

The ongoing failure to cleanup, mitigate the Hanford Nuclear Reservation is proof enough that we are not (yet?) mature enough to manage nuclear energy.

When the contaminates reach the Columbia River, every where downstream becomes uninhabitable. eg Portland OR.

Kind of surprising at this point that there’s not an area directly below the bottom of the reactor with a giant ceramic catch basin (or something similarly heat resistant) to catch these failures and cleared of pipes etc so when this happens cleanup workers know the location of the materials.

> Kind of surprising at this point

Fukushima was built when the nuclear power industry was 13 years old. Now it's 63 years old.

You are seeing the folly of youth, with consequences delayed 60 years, not a design that would be typical of new construction.

Also, from what I understand, they ignored the reports that recommended to put the backup generators on higher ground and to make the sea wall higher. Fukashima is the worst case for that design I think.


A great article about another plant, closer to the epicenter, owned by another company that did things right.

It breaks my heart that these guys also have to be in a shutdown state. TEPCO should be forced to hand over all undamaged nuclear plants and responsibility (minus financial) to this company.

It seems like the regulators really failed. Short sighted actions and failure to fix past mistakes shouldn’t be allowed. The other sad thing is that, this is the worst case scenario for that plant and it pales in magnitude, but it is overshadowing the sorrow and lost due to the flooding and earthquake.

Sounds like life :| Those cigarettes you smoked in your early twenties? Those beers you smashed working in IT? 63 will be interesting..

You know if you stopped smoking in your early twenties they’re not likely to affect you when 63. So this is more like smoking crack in your twenties.

> Those beers you smashed working in IT? 63 will be interesting..

If any, I'd guess this correlation to be negative vs. the general population

But but but beer is healthy! It's what people drank all the time in the middle ages etc, it was better than the water.


The trick is not to give in to peer pressure.

elaborate plz

Nuclear scientist's weren't like "naive" teenagers though.

Sure the design could've been better; However by your logic they had 50 years to take extra safety pre-cautions and improve the structure.

In-fact, it still absolutely amazes me it was even running at the time of the disaster and built on a coast in a country notorious for Tsunamis.

> improve the structure

The key question is: Who would have paid for it?

Once running, much of the structure is considered to be radioactive. Work in active radioactive areas is expensive and time consuming. Without shutting down the reactor entirely followed by an expensive cleanup, doing major structure upgrades to the reactor chambers is virtually impossible.

They also couldn't just decommission it once they realized their errors and rebuilt another one somewhere else - again the costs would have been astronomical.

People are terrible at managing (what was then) theoretical risks. If you can't convince people and companies to move out of proven high-risk earthquake areas, imagine trying to convince tax payers to pay billions to upgrade or move a functional-but-theoretically-vulnerable power station.

> Who would have paid for it?

The disaster could have been prevented by the simple expedient of elevating the backup generators, or putting them in flood-resistant bunkers. Cheap.


The actual tradeoff would have been not just this one mitigation, but all the mitigations for all the equally probable risks. Including all the assessments to find out what those risks would have been.

I don't think you can say, "hindsight," when the mitigation was actually recommended in reports that were made before the event. It's only hindsight when mitigations become obvious after a disaster.

The hindsight is in which mitigation would have been effective. In a different disaster, perhaps the generators would not have been the missing piece.

It's only really possible to make a determination about whether it was hindsight or not after seeing the prominence of the recommendation. Suppose I tell someone a thousand times, "you should wear seatbelts," and once to fix their taillight. Then they are killed in an accident after being flung from a vehicle while not wearing a seatbelt. It would not be hindsight for me to say, "they probably should have worn a seatbelt." Maybe it would be if they were killed in a freak accident involving an unfixed taillight.

Unfortunately, given I have only second-hand knowledge of these reports' existence, and given they are probably not in my native tongue, I'm not really in a position to validate what the situation was vis a vis the generators. However, generators positioned on the coast, behind a low seawall, in a country that is regularly inundated by tsunamis, appears to be an entirely predictable failure mode. Not quite to the degree of not bringing a parachute on a skydive, but in that direction.

I agree, I think that the language barrier is not a problem when you see those generators sitting right behind the seawall.

It's like in New Orleans, where the emergency generators were located in the basements below sea level. There's nothing subtle about that. Sorry, but how daft can one get?

> Hindsight

I disagree. Failure analysis does not start with "assume the seawall will never fail." It starts with "assume the seawall fails. What are the consequences?"

Given the location of those generators, it was obvious that a breach would take out CRITICAL generators, and it would have been cheap to remove that vulnerability.

Another cheap remedy would have moved the hydrogen vent pipe to vent outside, rather than INSIDE AN ENCLOSED SPACE FILLED WITH SPARKING ELECTRICAL EQUIPMENT.

> Nuclear scientist's weren't like "naive" teenagers though.

Every industry makes severe mistakes early on and eventually irons them out with time. Are you arguing that's not the case?

> However by your logic they had 50 years to take extra safety pre-cautions and improve the structure.

Economically retrofitting an old reactor with safety mechanisms is a much more challenging task than designing new reactors correctly. The industry quickly learned how to build reactors that could handle neglect and abuse, but by then the reactors under the ground were out of their control, and were essentially ticking time-bombs. Everyone in the industry knew it. The IAEA had been complaining about ancient, unsafe reactor designs in the ring of fire for decades when Fukushima happened. So it goes.

> Every industry makes severe mistakes early on and eventually irons them out with time. Are you arguing that's not the case?

Given that they already knew this could happen when they built it, what could you plausibly claim has been learned?

Moving several EDGs and support system a couple kilometers is a small task in comparison to the design, qualification, construction, and training associated with a new power reactor design.

There’s nothing very complicated about the EDG buses that supply safety-system components.

The cables from the diesel generators a couple of kilometers away could have been destroyed by the tsunami or another earthquake.

This isn’t relevant to the fact that upgrading safety and safety support systems is less costly and a smaller engineering task than designing a new reactor.

Upgrades to such systems, including flex interfaces, has occurred across the US fleet in the years following Fukushima, while exactly zero new reactors have been designed and built.

Sure, there are better designs for EDG siting and support system integration. This is completely besides the point. The point is, even moving the whole safety support system kilometers away is cheaper than designing a new reactor, which I think should be a pretty uncontroversial statement to engineers familiar with the complexity of license approval for power reactors.

Nuclear reactors need to be built next to a large body of water for cooling. So Japan didn't have a choice when they wanted to have nuclear power.

> Nuclear scientist's weren't like "naive" teenagers though.


Not only scientists but the whole humanity is acting like "naive teenagers" here.

I'd go even further: the bigger the aggregation of people, the younger they act. The UN is basically kindergarten with fancy clothes and longer words.

Every year the chemical industry kills and contaminates far more.

True I’d forgotten how old Fukushima was.

That's part of some newer reactor designs: https://en.wikipedia.org/wiki/Core_catcher

Expensive. The concrete can also crack in the event of an earthquake.

Not as expensive as having to clean up three reactors worth of nuclear meltdown and a few exploded reactors.

I'm sure they can prevent the concrete from cracking in an earthquake.

Cheaper solutions exist, such as the one with borosilicate sand on the bottom of the reactor. Building passive cooling pools with those resources is orders of magnitude more useful because it prevents a meltdown rather than attempting to catch the molten core. The ESBWR uses such a passive cooling design.


I have seen reactor designs with a borosilicate sand pile under the reactor. Presumably the molten core will turn the sand into borosilicate glass which not only freezes at a high temperature but is also a radiation shield.

I think that is easier said than done, the temperatures are in the several thousands of degrees here.

And radioactive. Which changes the atoms if which your containment material is made of. Which makes things much, much more difficult.

Clay would hold that wouldn't it?

Depends, most types of ceramic are molten by 1300-1400 centigrade

These catchers exist, they use a ceramic-concrete mixture with a massive melting temperature.

I remember reading articles right after the disaster saying some engineers/scientists tried to warn people that the design had some critical safety flaws..


But not sure this really points to lack of caution?

Personally, I think we need low carbon power sources, but emotionally (irrationally?) nuclear fission always feels like "apes toying with God's fire"

I still think they should fight fire with for. A small tactical nuclear bomb just inland of the plant could blow it all into the ocean where the material would sink. ;-)

That would just end up like the Marshall Islands where they did the H-Bomb tests. They are still too contaminated to live on.

Wasn't something like that poured under Chernobyl after the accident which prevented the radioactive slurry from entering deep into the ground?

The Russians handled the catastrophe better and faster. International help sender them low tech robots, Russians poured tunnels below within days/weeks with lot of human contractors. But Japan is doing little. Contaminated fluids leak into the sea that swaps to Hawaii and west coast ever since 2011. It's the local culture of loosing face that seems to be at odds with handling it and a major corruption problem. After 6 years Japan has done so little, compared to the Chernobyl Sarcophagus and all the handling inside and ever since. Why is there not more international pressure to Japan to do more and do it faster? They have to do it no matter what the costs are or if the have the resources, it doesn't matter - the rest of the world population will thank you for less pollution. https://en.wikipedia.org/wiki/Chernobyl_Nuclear_Power_Plant_...

Perhaps it's a language barrier, but this comment makes no sense. The low-tech robots you speak of were uniformly useless, and the people working on the initial cleanup and containment were sent on what were essentially suicide missions. Information is easy to find; just google for stories about the Chernobyl liquidators.

Regarding the radiation, I think you've fallen victim to ignorance of basic facts about the nature of radiation and the oceans. Pretty much anywhere in the Pacific, radiation from Fukushima quickly dropped far below environmental background levels [1].

1 - http://www.whoi.edu/page.do?pid=127297

Here's a good quote from the source above: "The highest levels of cesium (10 Bq/m3) attributable to Fukushima that we have measured were found 1,500 miles north of Hawaii. Swimming every day in the ocean there would still result in a dose 1,000 time smaller than the radiation we receive with a single dental x-ray."

I think they tried, but the radiation was too hot and melted through the steel and concrete below. This was an old facility, so it was probably built with that idea in mind. It just failed.

On a related note, I live in Chiba, which is a fair distance south of Fukushima. The rain and wind drove the radiation into my area after the accident. I still have interesting radiation readings in my rain gutters and spouts.

I wonder what they do once the robot sees the uranium? I mean the robot itself is now heavily contaminated. Do they just leave the robot down there? Or do they somehow decontaminate it so they can use it again?

> I wonder what they do once the robot sees the uranium? I mean the robot itself is now heavily contaminated.

Contamination isn't as dramatic as you'd think, it's mostly superficial : you have radioactive dust sticking on the robot, and you "just" need to wash it thoroughly to remove the contamination.

People usually have a wrong vision of radioactive contamination : they think being exposed to radiations makes you radioactive in return. In fact, it doesn't : being exposed to a radioactive material (which means you get struck by gamma rays, alpha and/or beta particles) doesn't make you radioactive. You can get contaminated with radioactive dust (which is a real problem if you ingest or inhale it, since it's hard to wash there) but you don't become radioactive yourself.

The mistake didn't appear out of nowhere though : things exposed to neutrons becomes radioactive (they become activated) and neutrons are emitted by nuclear fission, which occur in a exploding atomic bomb or a working nuclear plant. But when the plant shuts down, the chain reaction stops and so does the neutron emission. All that remain is radioactivity, as fission products keep decaying.

That being said, in practice I'm not sure the electronics in the robot is in a good enough shape to be used again …

Robots just kept dying in there all those years [1]. I reckon they are disposable, in effect.

[1]: http://mashable.com/2017/03/03/fukushima-robots-fail/

That's the primary reason it's taken so long, as far as I understand. It's not that it was hard to find the location, per se, but that the robots didn't last long enough.

If anyone's interested in related reading, there's a manga called Ichi-F[0] that walks through the daily life at Fukushima Daiichi.

[0] https://kodanshacomics.com/series/ichi-f/

Wow, thank you! The art is pretty good overall and the story seems well done enough. There are 39 chapters according to where I found it to read online but MyAnimeList (MAL) says 24 chapters from 3 volumes.

More info on MAL here: https://myanimelist.net/manga/61341/1F__Fukushima_Daiichi_Ge...

> At the plant’s entrance, a sign warned: “Games like Pokemon GO are forbidden within the facility.”

Was this a thing people were doing? Going to a nuclear disaster site as part of a game?

Signs forbidden the use of games like Pokemon Go are quite common across Japans. You find them at many Temples etc. Many cafes/bars/eateries have signs out the front with drawings of the Pokemon you'd find nearby with Pokemon Go.

Source. Went through Japan playing Pokemon Go.. saw many many Japanese people playing Pokemon Go. And signs.. signs with Pokemon everywhere.

Probably nowhere near as dangerous but I think its interesting. https://widerimage.reuters.com/story/in-the-shadow-of-cherno...

A number of Russian middle class volunteers who fought in Donbass war treated it as kind of similar experience - an adventurous game/vacation, a "noble quest to defend 'Russian world' from dark forces of fascism and imperialism".

Is there an evidence of that? We could open a case for these war crimes.

It wasn't war crimes, it was participation in a civil war fighting armed volunteer and regular forces of the other side.

Could also be workers at the site on their lunch breaks.

maybe they thought they could find a genuine pokemon?

It's exactly the sort of place where you'd find the baddest pokemon in the game.

Definitely the kind of place you should find Ditto.


reminds us that nuclear kills much less than regular earthquakes, car accidents, or air pollution due to the burning of fossil fuels...

Most radiation kills are due to slow secondary effects, so it's relatively easy to get out of the way. I don't think anyone really argues that if people would move back before deconamination they would all be fine.

Just for reference, the number of people worldwide who died due to contamination from atmospheric atom bomb testing is estimated to be 430 000 by the end of last century:

"Radioactive Heaven and Earth, The health and environmental effects of nuclear weapons testing in, on, and above the earth", pages 163-165

That is an extrapolation using the unproven linear no threshold hypothesis.

Isn't that the same as attributed to burning coal in undera year world wide?

Those were also tests where the escape of massive amounts of radiation into the environment was a planned, even if indirectly, effect.

Also, as a sibling comment said, that numb is probably overstated by a large amount.

Gah -- reminds me of the press at the time talking about detectable radiation on the West Coast of the US. Yeah -- you know what else is detectable radiation? Stars from light-years away. I was shocked to see Germany respond so strongly to Fukushima. I think fortunately for the world solar and wind have become so cheap we can give up on making the world more rational about nuclear power.

Go and live there if you think that it is really harmless. I would rather not honestly after it took them 6 years just to get the first image of the corium after endless attempts.

Well, just note that after Chernobyl, Western Europe did live there. The size of the smoke plume (1000s km), radioactive material released (6000kg), and wind/weather during the event affected almost every country including Spain, England, and Norway. Those 300M people arguably recieved higher doses than you would living in the evacuated Fukushima area.


The point is that it remained contained... that's good. With prpoer monitor wells even the ground water need not be badly contaminated.

Been near there just like a week ago (Tomioka town). Opened up for resettlement this year. Lots of damage from tsunami, but new buildings are being constructed and there are several functioning hotels and convenience stores. There's massive work going on to decontaminate the remaining areas by 2020. As long as you don't go inside of the nuclear station it should be ok.

Given the choice, I would.

Thankfully for the world and the future of all life on earth its not a binary choice between fossil fuels or nuclear.

And that's with incompetence and neglect.


Personnel had an insufficiently detailed understanding of technical procedures involved with the nuclear reactor, and knowingly ignored regulations to speed test completion

And a Japanese reactor that didn't melt down:


Before beginning construction, Tohoku Electric conducted surveys and simulations aimed at predicting tsunami levels. The initial predictions showed that tsunamis in the region historically had an average height of about 3 meters. Based on that, the company constructed its plant at 14.7 meters above sea level, almost five times that height. As more research was done, the estimated tsunami levels climbed higher, and Tohoku Electric conducted periodic checkups based on the new estimate.

There's just no good reason for either Chernobyl or Fukushima. Both were preventable by following simple safety procedures.

>> And that's with incompetence and neglect.

Yes, and rightly so. Engineers must design around human fallibility. They don't get to blame human error and claim the whole system is otherwise perfectly safe. Either the system is safe under conditions of human fallibility, or it is unsafe.

>> There's just no good reason for either Chernobyl or Fukushima

Of course there is reason. Humans are part of the system and a relatively weak part at that.

How do engineers design around the propensity of politicians to kick the can down the road?

Not every project is the right project for you right now. Select well.

Politicians' influence wanes, while engineers' waxes.

Dual major in theology?

That is the fundamental problem with nuclear power. You can trust the technology but you can't trust the humans.

So you extrapolated what will happen to the spent nuclear fuel that already began to leak in some places and did the math? I'd like to see it.

> reminds us that nuclear kills much less than regular earthquakes

Stupid comment. Would you relocated near Fukushima or Chernobyl? Maybe you should. You would educate yourself and change your mind. And you would have to life with the related health issues. (The same for evil greedy owners of such energy companies)

I work in a big city. It is polluted by cars, trucks, heating. That pollution kills 2 or 3 hundreds of people every year in that town. That scares me a lot more than the hypothetical explosion of the nuclear plant which I live 40km close...

Actually you cannot. They do not let anybody live near to these sites.

I’m not worried about how many people nuclear power kills every year. I’m worried about how many people it kills every hundred years. A major nuclear disaster, however unlikely, has the potential to kill millions of people and leave a big portion of the Earth uninhabitable for centuries. Just because we haven’t seen one on that scale yet, doesn’t mean we never will.

Ok, let's do a Fermi-like estimation.

Estimates on the number of deaths related to coal generation vary from around 13,00 to 30,000 per year in the US [1] and 500,000 per year in China [2]. The current world population is 7.6 billion, of which the US and China account for approximately 1.8 billion people. Let's round the coal-related death rate way down for easy math: 10,000 per year in the US and 100,000 per year in China. Then, multiply that rate by the world's population, and you have, let's say 450,000 coal-related deaths per year worldwide. This is a really squishy number, but we only need approximations here.

You were concerned about how many people would die every hundred years from nuclear disasters, so let's see if we can work today's 450,000 per year estimated deaths backwards for the last hundred years.

The world population was somewhere in the neighborhood of 1.8 billion people in 1917. Assuming linear growth (I know, I know) and a strong r-value correlation for population vs. coal-related deaths (arguable, but again, Fermi estimate), we have to sum .00006 * population from 1.8 billion -> 7.6 billion, and we end up with approximately 28 million people.

Which is to say, if we could gather up all the deaths, worldwide, from coal, over the last hundred years, and convert it into a single disaster, it would kill the entire city of Shanghai, and New York for the apple on top.

That would have to be one hell of a nuclear disaster.

Now, there are arguments to be made that the energy we've received from coal has also powered hospitals and technology which have saved or improved people's lives. There are also arguments to be made that the side-effects of coal (hospitalization, environmental disasters) cause the death toll to absolutely pale by comparison.

And again, I've rounded these numbers down at every stage of the calculation.

[1]: http://www.catf.us/resources/publications/files/The_Toll_fro... [pdf]; it includes its own numbers, at the 13,000 estimate, and the EPA's, at 14,000 to 36,000 range.

[2]: https://www.nextbigfuture.com/2011/03/deaths-per-twh-by-ener... (blog, but includes lots of supporting links; I'm open to alternative sources that give vastly different estimates).

There are very few people who are anti-nuclear power who are pro-coal.

Even ignoring renewables, gas solves many of the worst problems with coal.

Sure, but even natural gas and rooftop solar have higher rates of death per year than nuclear. (In my second link above.)

In a world in which we must choose the lesser of evils for energy, nuclear is among the least evils, yet faces the greatest overall public resistance to new installations.

I dunno - even that source itself says that the death rates from solar would fall using better construction methods. It also notes (in the case of wind) that increased take up is associated with lower death rates ("Wind power proponent and author Paul Gipe estimated in Wind Energy Comes of Age that the mortality rate for wind power from 1980–1994 was 0.4 deaths per terawatt-hour. Paul Gipe’s estimate as of end 2000 was 0.15 deaths per TWh, a decline attributed to greater total cumulative generation.")

I'd also note that the very low rates of death from nuclear power do not appear to include construction deaths, which are the only source of death measured from wind and solar.

>even natural gas and rooftop solar have higher rates of death per year than nuclear.

the difference here is that no event can significantly change the death rate from gas or solar whereis one wrong cough by nuclear power plant worker and we have Chernobyl with thousands of deaths (in particular in Belarus which took the majority of the Chernobyl hit - about 5000 extra thyroid cancer cases (normally a rare cancer) in the people who were children at the time plus doubling (and in some areas tripling) of the rate of the most frequent cancer - breast cancer (typically 1 in 7 women would get it during lifetime, so doubling means additional 15% of all the women in the affected area would get it) in the areas close to Chernobyl like the Gomel and Mogilev regions plus very significant increase in other frequent cancers of internal organs like colon,etc.)

Or counting it the other way - Russia and Ukraine both have the same - 0.0034 - incidence rate of cancer per year (despite the war and economic differences it is the same people with the same behavior/habits :), while Belarus where people are basically the same as in Ukraine and Russia and drink and smoke and eat the same - has 0.0052 incidence rate, ie. 50000 new cases per year instead of 34000 if they were to have the same incidence as Russia and Ukraine. 16000 extra cancer cases per year for several decades with mortality higher than 50% ...

>nuclear is among the least evils,

hardly so, giving the numbers i referenced above (compare it to coal - the coal's 700K/year deaths means "only" 1K/year for Belarus) and potential of any nuclear power plant to repeat Chernobyl - i'm aware about technical improvements of modern reactors, yet "stupidity will find a way"...

> yet faces the greatest overall public resistance to new installations.

still wondering why ? :)

Being anti-nuclear is pretty much accepting the status quo though. Modern nuclear power is much, much more sustainable than coal, scales very well, and is very safe. If you believe in a quick solution for energy issues then you shouldn't halt all nuclear development and leave fossil fuels for the next couple decades.

Being anti-nuclear is pretty much accepting the status quo though.

Elon Musk would disagree.

If you believe in a quick solution for energy issues then you shouldn't halt all nuclear development and leave fossil fuels for the next couple decades.

Nuclear plants take 30 years at least to get through planning and building. Gas fired plants or pump solar can be deployed within a year, Wind + Solar in even less time.

Also there was an interesting view on (against) nuclear by Naomi Klein :


I like nuclear, but her view makes a lot of sense to me.

Nuclear will never be able to compete with renewables on cost or deployment speed. It’s dead tech for anything other than space probes and military uses.

How? Nuclear tech is already much more developed than other renewables and it's incredibly efficient. The cost of solar is much higher than the cost of nuclear. Hydroelectric and wind are both lower, but they also require certain geography and can't be used anywhere. Nuclear is not dead tech at all, most of France's power comes from nuclear.

France is closing at least some its nuclear power stations (and has no plans to build new ones): https://www.reuters.com/article/us-edf-nuclear/france-to-clo...

(Also, nuclear is not a renewable by an sensible measure)

Nuclear is very slow to build in the Western world. Finland is already in their 12th year building Olkiluoto 3

Is that 0.04 deaths/TWh sourced anywhere?

I've seen it before, but trying to trace it down is... troubling.

There's this report[1], where they only count accidents where more than 5 people were killed. This coincidentally manages to avoid counting all accidents in nuclear plants, where in the US alone there were 8 deaths[2]. I assume other energy sources would see a jump too, but that doesn't give me great confidence. The number from that report is different anwyay.

[3] http://wps.prenhall.com/wps/media/objects/2513/2574258/pdfs/... references some authors which appear to have this 0.04 number, but I can't find the source.

[1] https://www.oecd-nea.org/ndd/reports/2010/nea6861-comparing-...

[2] https://en.wikipedia.org/wiki/Nuclear_reactor_accidents_in_t...

[3] http://wps.prenhall.com/wps/media/objects/2513/2574258/pdfs/...

"However unlikely"

This is where probabilities bite us. If the probability is small enough then the expected death toll will drop to almost zero which merits little worry, despite how horrific said event mightt be. It sounds like you're doing the natural, intuitive thing of picturing a very scary scenerio and then wanting to avoid said scenerio at all costs.

The problem is, while you're busy avoiding some almost-zero probability event, you're also nuking your ability to mitigate events with actual high expected deaths and loses.

Fossil fuels already kill on the order of millions per century [citation needed], so if you think nuclear power does the same, it means we should expect several Chernobyl level events in the next few decades. Are you sure your probabilities are well-calibrated here?

Also, some of the rough skimming I've done has me believing that cycles without possibility of medown can be built, cf. liquid salt reactors. IIRC, some of these even have really nice waste profiles with the worst stuff only having half lives in the decades and very low volume at that [citation badly needed].

Anyway, fear of nuclear power reads to me like a fear of planes over cars. Chernobyl and Fukushima were single, isolated events making them visible and viscerally scary like plane crashes. Fossil fuels, on the other hand, pick us off one by one, relentlessly, but never so loudly as to evoke that gut-level fear.

Every year it kills 100 times less than every hundred years, that’s how average works, no matter what exact period you’re worried about. Also, no nuclear disaster ever killed millions — it is barely possible even with nuclear weapons. Relocation and financial risks, yes.

Likelihood of such disaster is estimated to be too minor to not care about, say, “an asteroid kills the planet” movie scenario.



By nuclear disaster do you mean weapons use or just a power generation accident? I've never heard of a power plant accident potentially leaving a big portion of the Earth uninhabitable for centuries, but if there is something please enlighten me!

Uninhabitable? Maybe for humans. Wildlife grows back stronger:


The fact that toxic radiation is less lethal than humans is an indictment of humans, not an endorsement of radiation.

If I'm reading the article right, the robots actually made this discovery back in July.

As seen as another HN thread, seemingly relevant here as well:


The YouTube video with images of the core that nytimes linked, is one of those spam news videos using text-to-speech.

I was wondering about that. Was about to adjust my false-positive filter for YouTube click spam. I mean, if the NYT links to it...

Early on there was considerable talk about the contaminating impact this might have on the Pacific. Has anything come of that?

Water sampling happens frequently at various points near the reactor, all of which showed levels at expected bounds to date.

Most of the scary charts were fake: https://www.snopes.com/photos/technology/fukushima.asp

What is the article talking about when they say "radiation-hardened materials"? What kind of materials might that be?

I don't know what they did in this particular instance, but basically there are two things you can do: shield, or in the case of electronics, use larger parts.

The smaller some piece of electronics is, the smaller the charges in there are, and the easier it is to introduce errors with ionizing radiation.

And the design of the electronics might help with radiation tolerance. Computation paths could be redundant to detect/eliminate bit flips due to radiaton.

(Some server Power cpus seem to run parallel in pairs, comparing the output at critical parts to detect cpu errors)

Basically the same as in space exploration. Also running at very low MHz.

There is a third thing, which is to use a dopant which reduces minority carrier lifetime and provides radiation resistance when manufacturing the semi-conductor. Platinum works really well for this. Unfortunately, this can be a poor engineering tradeoff for some kinds of electronics (power transistors for example) and usually increases electrical resistance. AFAIK nobody manufactures platinum-doped microprocessors.

I used to be a product manager for radiation measurement electronics, and we used platinum-doped diodes for the part intended to go in the beam.

See for example: https://academic.oup.com/rpd/article-abstract/17/1-4/527/311...


"Neutron embrittlement" is a term to chase down. Generally people talk about the effects on metal, but I'm sure neutrons affect ceramics, too.

One of the issues with metal is that it starts out as a ductile material and neutrons can embrittle it by introducing voids and dislocations. (i.e. basically moving the atoms around from their ordered crystal state) I'm sure some of the same mechanisms apply to ceramics but they're fairly brittle to start with so designs/applications using ceramics need to account for the fact that they're brittle from Day One.

What causes a robots electronics to go bad in radioactive environments?

Web link not bypassing paywall for me, anyone else? Or am I in some experimental cohort? :)

It worked for me. Anyway, here's an archived copy:


> "... exotic space particles called muons "

welph, that's my eyes rolling right out of my head. I mean really, "space particles"! The might as well call all metals "supernova remnants" -_-

Would you prefer for them to be referred to them as "Cosmic Rays" :) ? To be honest, "Space Particles" sounds less silly and more descriptive. It also emphasizes that they're not generating the muons themselves, but collecting them from space.

EDIT: Though I guess, now that I think of it, it's a bit unfair to refer to muons as 'exotic'. People will typically encounter thousands of them in a day [1].

[1] http://cosmic.lbl.gov/SKliewer/Cosmic_Rays/Muons.htm

[1] "Muons arrive at sea level with an average flux of about 1 muon per square centimeter per minute."

Yeah, of course! They are cosmic ray muons after all, as in "muons created by cosmic rays". The words "space particles" is more correctly applied to dust (the type in space obvs.) and stuff like that in my opinion.

Honestly "space particle" to me sounds to be the same sort of suspect phrase as "space pen".

Aren't muons terrestrial particles created by cosmic ray impacts on the atmosphere, though?

Well, yes; but calling them "exotic-in-the-sense-we-don't-talk-about-them-very-much-even-though-they-pass-by-all-the-time-that-got-created-when-an-actual-space-particle-that-wasn't-that-exotic-like-a-proton-or-helium-atom-hit-the-atmosphere particles called muons" doesn't quite roll off the tongue. :)

They ultimately (and not in the we're all space dust sense, more like 2.2 microseconds ago sense) are caused by interactions with particles from outer space, so calling them space particles, isn't that bad. :) But yeah; it's does elide that aspect of them.

SO! it never made it to China LOL

Why in fuck is this a link to mobile?

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