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Nuclear reactions are smoldering again at Chernobyl (sciencemag.org)
201 points by yosito on May 6, 2021 | hide | past | favorite | 206 comments



> Any remedy he and his colleagues come up with will be of keen interest to Japan, which is coping with the aftermath of its own nuclear disaster 10 years ago at Fukushima

I can't believe Fukushima was 10 years ago already. It feels like it was just last year.


I can't believe that an earthquake and tsunami that killed 20,000 people is called a "nuclear disaster"


The Fukushima Daiichi nuclear disaster was caused by the Tohoku earthquake and tsunami. They are separate, but related disasters. Despite the low fatality rate, there is no doubt that it was a disaster. Radioactive material was released and 150,000 people were evacuated.


Massive amounts of radioactive material were released right in to the ocean, threatening the planet itself.

Imo: worth being defined separately from the earthquake, and worth being called a disaster


If that's a disaster, what the hell is something that killed 20,000 people?


Also a disaster.


> I can't believe that an earthquake and tsunami that killed 20,000 people is called a "nuclear disaster"

It seems that you missed the part where a nuclear plant was destroyed by those same tsunami and earthquake. Everybody is talking about how to fix it since 2011, so it must be something big.


I think his point was that the tsunami killed 20000 people, and the nuclear power plant killed one, yet people talk about the nuclear power plant as if that was the only issue. This is kind of disrespectful to the actual victims.


> the nuclear power plant killed just one

Yes, I'm aware that some people will keep repeating this damage control PR stunt a thousand times, and that other naive people could even believe them and spread it, but it will still be false (and irrelevant).

Every time that we talk about Fukushima we have the but "almost nobody died" rabbit out of the hat again. We have yet discussed why this is false ten times and frankly I'm a little tired about this tactics of draining our energy making us to repeat obvious facts again and again until everybody quits the room.


One scientific paper predicts around 200 excess deaths eventually. A single percent of the death toll of the tsunami.


And there is only one confirmed death from the nuclear incident.


> And there is only one confirmed death from the nuclear incident.

There's plenty of evidence of increased cancer rates in the affected areas. That's never a statement made in good faith in the context of nuclear disasters, because radiation effects on the environment, including the people, have a very long tail.

You're basically saying nothing, while ostensibly implying there's nearly zero risk of fatalities.


Could you point to a peer reviewed paper that attributes QALYS lost of fukishima vs QALYS lost from the tsunami as a whole. Ideally one which also looks at QALYS from fossil fuel power plants too.


One $200,000,000,000 death.


Interesting that years later the sensationalist doomer blogs[1] turn out to be correct[2], in contrast with the common obviously false mantra of "there is no nuclear waste problem/safety issues"

[1] https://cuttingthegordianknot.wordpress.com/2012/05/02/houst...

[2] https://earther.gizmodo.com/japan-s-new-fukushima-plan-dumpi...


Correct in the mere fact that nuclear waste is being released into the ocean. Still incorrect in the sense that this is a significant issue worth worrying about. The waste mixes with the ocean water and dilutes to safe levels.

The Soviet Union and the United Kingdom both dumped nuclear waste into the ocean for decades: https://en.wikipedia.org/wiki/Ocean_disposal_of_radioactive_....


First, nobody said that. That is a strawman you made up.

Second, tritium is an extremely harmless radioactive isotope, probably the least harmful one there is. Releasing water containing tritium is absolute and definitely completely harmless as well, and a good decision.


I remember getting bagged on at the time for saying it was going to take 30-50 years to clean up Fukushima. We're 35 years out from Chernobyl. I think Three Mile Island took 15 years. And now 10 year out with Fukushima.


The Chernobyl disaster is simply unimaginably expensive. The total costs so far are estimated to be in the hundreds of billions of dollars. The new containment structure that was finished in 2019 was $2,000,000,000 alone, and dismantling the reactors and cleanup is scheduled to take another 45 years.


If hundreds of billions to address the first nuclear meltdown in world history is unimaginably expensive, what do you call the "conservative" estimate of covid-19's total cost of "$16 Trillion" for the US alone? Source: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7604733/ And that's assuming its all taken care of by fall of 2021.


In terms of cost per citizen that's actually the same order of magnitude as the $700 billion quoted here [1] (if as citizens we count Ukraine and Belarus, which is of course not totally fair).

But yes, Covid is also incredibly expensive, and with a couple of years of hindsight we will no doubt talk about its major political impact just like we are talking about Chernobyl contributing to the fall of the Soviet Union.

1: https://globalhealth.usc.edu/2016/05/24/the-financial-costs-...


There’s a cost to building back better.


Still cheaper than the Iraq and Afghan war though.


The Chernobyl accident was arguably a major factor in the eventual downfall of the Soviet Union and therefore the end of the Cold War so perhaps some good did come from those awful events.


The collapse of the Soviet Union was a disaster in itself. People had their savings wiped out, lost their jobs, and had to barter beg and steal just to feed themselves. Organized criminals bought up the state's assets for pennies on the dollar and set themselves up as oligarchs. Several former soviet allies turned into dictatorships or failed states.


Sorry, but what savings? I come from Baltics. Born late years of Empire. Most of SU people lived on the edge powerty. Ofc if you were in party or releated to defense then you had very good or decent living standards. But for my family where all of 4 grandparents were from kulaks almost zero chanche to get out from specific kasta.


No, the creation of the Soviet Union was a disaster of unimaginable scale. It simply had to end at some time, because it was corrupt and the economy inefficient in every way and morally bankrupt. The forced annexation of other countries and deportations of nations inside the SU were horrible crimes.

Do you suggest that the soviet union should not have collapsed?


> Do you suggest that the soviet union should not have collapsed?

Perhaps it could have collapsed in a better way?


It killed much fewer people collapsing than it killed when existing. So it collapsed in a pretty good way, considering the alternatives.


I think there were ways for the Soviet Union to have gone away that didn’t involve Russia (and to varying extents, the other states) becoming the kleptocracy it is now.


> I think there were ways for the Soviet Union to have gone away that didn’t involve Russia (and to varying extents, the other states) becoming the kleptocracy it is now.

It was, and rather violent: go, and cleanse the remnants of the old system. A missed opportunity now.

Instead, people let them live for them just to come back in 9 years time.


I also think there were ways it could have gone away while killing millions. And I am not exaggerating: while living through the collapse our parents kissed us kids goodbye and sent us to the country side. They fully expected the communist apparatchiks to shoot protesters point blank in the streets. And it some cases, they did.

Let’s just be glad it went away and pray it never returns: it was one of the greatest horrors this Earth has ever seen.


> Let’s just be glad it went away and pray it never returns

This optimism is very premature. CPSU has morphed into Russian mafia, and the current Russian Kleptostate, and ChiComs... well just turn on the news any day.


> The collapse of the Soviet Union was a disaster in itself.

A very positive "disaster" for multiple countries that were occupied by Russia since the end of the war. We regained our freedom and started to catch up to the NATO countries.

The nearly 50 year under Moscow's boot was a much bigger disaster and, although I was born in a communist state, I'm glad I could grow up in a now free and democratic country.


Thanks for your perspective. It's always good to remind people of the realities of life under communism, given its resurging popularity amongst some young people who have no living memory of it.


That returning popularity is no accident: when it collapsed, its propaganda machine mutated and adapted to the west. Now it has a new master rising on the ashes of the old empire and it started its work.


For sure, nothing to do with the rising inequalities, the economic perspective of the younger generations, and of course the whole climate and resources consumption issues the last decades have brought that maybe make some people question if we are on the right trajectory.


Oh, sure, good old Soviet Union was the master of equality. Everyone was equally hungry and equally oppressed. Everyone, of course, except them: the politically connected, the unelected ruling class. They and their good friends, the secret police.

But the propaganda machine LOVED telling us how much better we had it in such an equalitarian society and what a nightmare was to live in the decadent West where the rich took advantage of the poor. We were literally waiting for capitalism to fall... while queueing in line for the allotted bread, flour and sugar rations.

They were the masters of ecology as well. Just read up what happened to the Aral Sea and, you know, the subject at hand, Chernobyl.


Of course I was not defending Soviet Union but commenting on the returning popularity of "communism", and by that I was thinking of Marx ideas, notably regarding the economy[0]. I'm not sure there is really a returning popularity for Stalinism.

[0]https://en.wikipedia.org/wiki/The_Communist_Manifesto


Marxism, communism, Stalinism - they are one and the same cancer: the inhuman system under which people's rights are forcefully confiscated and replaced with the all powerful State that knows better what you need. For your own good and the betterment of all mankind.

The people praising such a system it are either the purely evil overlords-to-be or their "useful idiots" losers blinded by desire of a of personal gain they are utterly unable to obtain in a meritocratic, free-market, capitalist system.


The Tsar was bad too. Cold comfort to the millions who were massacred after the revolution.


Who is arguing that? I never seen any credible evidence that it contributed in any significant way to the collapse of the Soviet Union.


Mikhail Gorbachev for one

https://slate.com/technology/2013/01/chernobyl-and-the-fall-...

Edit: Chernobyl: The History of a Nuclear Catastrophe by Serhii Plokhy also makes a claim that the accident let to political instability in the Ukraine which certainly didn't help with the integrity of the SU.


Gorbachev is directly responsible for collapse of USSR, — he ruled it when it collapsed. So he is responsible for both of the disasters.

Shouldn't you be a little skeptical, when he tries to blame one of his disasters for another?


Of course I'm sceptical - but given other accounts of the times that I have read I haven't seen anything in his account that seems fundamentally wrong.


Well, Mikhail Gorbachev has actually written about specifically this. You'd think he'd be a reliable source.


About as credible as you're going to get, I imagine


My perception of it is that the collapse had already started and was probably inevitable, but the Chernobyl disaster accelerated it and was a metaphorical nail in the coffin, further reducing any chance there might have been at recovery.


It’s the most expensive wildlife refuge in the world.


$2B is table stakes for anything in heavy industry. I haven't heard of a new oil refinery for anything less than $10B in a while.

I'm not saying Chernobyl wasn't a disaster. I'm just saying, as far as heavy industry goes $2B isn't much. I know that's hard to fathom but it's true.


Yeah but that refinery starts making money at some point. With Chernobyl, the $2B is completely gone.


A new nuclear plant can cost up to $10B. Spending $2B per 100 years to keep the worst disaster in nuclear energy safe and secure doesn't actually sound like a bad deal to me, in context. Of course the actual disaster in totality cost much more - up to $700B in impairment [1], overwhelmingly opportunity cost.

Further, consider that the Chernobyl complex did already produce value, and for many years. In fact, there were four reactors at Chernobyl. No. 4 is the one that suffered the catastrophic failure in 1986.

However the remaining 3 reactors continued to operate for many years. No. 2 was shut down in 1991, No. 1 was shut down in 1996 and No. 3 was shut down in 2000.

Even that was reluctant, the Ukrainians only agreed to shut them down in exchange for assistance with the NSC and putting up 2 new reactors, Khmelnitski 2 and Rovno 4.

[1] https://globalhealth.usc.edu/2016/05/24/the-financial-costs-...


Considering renovation of one of the reactors in the STP (South Texas Project) nuclear plant cost ~$5B I find that $10B suspiciously low. The renovation project I was made aware of was supposed to be done by Fluor. I don't know if it took place.

The Wikipedia page for STP talks about some $10-14B for two new reactors on the existing site. Originally applied for circa'07. If the reactors ever get built they will cut down on natural gas usage and be more more profitable than gas plants over their 25+ year lifespan.

I can only imagine a modern net-new nuclear power generation facility in the most hospitable jurisdiction would cost beyond $20B when all is said and done.


> A new nuclear plant can cost up to $10B

you forget the $40B in cleanup costs if no disaster happens, of course disaster or cleanup costs will be socialized in "developed" countries. all cleanup costs were grosly underestimated, in germany and everywhere else.


Not to mention the site will need to continually rebuild the sarcophagus around it until half-lifing makes the sarcophagus unneeded.

The current one is only designed to last 100 years.


The objective of the New Safe Confinement is to shelter the site and allow for safe demolition of the structure and disposal of the material on the site. There will probably be some sort of "cap" over the site for a long time but it will not need to be as expensive or technically sophisticated once that work is done.


I'm considering the "safe demolition and disposal" to cost multiple orders of what it would cost to rebuild the containment ...

so yes, at some point the new containment cap need not be as expensive, but by the time we have gotten to that point, the site will probably have consumed a lot more money than just building the same containment over and over again. Some future leader(s) would probably do the calculations and just say "let's build another 100-year-containment so the next generation can deal with the disposal" and pocket the money.

It's the "tech debt" discussion embodied in real life.


"only"


Yes "only", meaning it's insufficient for the long run.

It's estimated that the ruins will remain highly radiactive for 20,000 years, meaning that a scarcophagus-like containment is needed at least for that long. If human technology remains as is (ok I am really hoping for tech advancements in this area), we will need to build 200 of such structures if the design specifications work as planned.

The area is only "safe" because we keep the site contained. Without renewal of the containment structure, the radiation will spread.

https://www.power-technology.com/features/making-chernobyl-s...

"Meanwhile, Reactor No. 4, now covered by the New Safe Confinement, is estimated to remain highly radioactive for up to 20,000 years. "


We do fuck all about carbon dioxide killing our planet, but are "extremely concerned" about the fact that people will have to spend some money on one building. That's as close to "non-concern" as we can have.


On the scale of the relevant half lives, yes, "only" a century:)


$2B is just the new containment structure. Wikipedia lists the original cleanup as costing $68B (inflation adjusted). This article [1] lists the total economic cost as $700B

[1] https://www.thebalance.com/chernobyl-nuclear-power-plant-dis...


By comparison, BP paid around $65 billion for the Deepwater Horizon cleanup, fines and claims [0]

[0] https://www.reuters.com/article/us-bp-deepwaterhorizon-idUSK...


> BP was paid around $65 billion

That's "BP paid", I believe.


These days I'd be more inclined to believe a corporation got paid 65bn to clean up it's own mess than they paid 65bn to do it.


Same. That's why I double-checked.


Yes, just a typo, fixed now!


The Chornobyl disaster is so expensive, that it collapsed the Soviet Union and put a hard burden on economies of Ukraine and Belarus for 20+ years. The full price of cheap nuclear energy is extremely high.


While Chernobyl may have played a role in the Soviet Union's collapse, it wasn't the only factor, and it wasn't the financial cost of the disaster that contributed to the collapse, but the loss of public trust in government.


Good news: we've paid for it, it was the costs associated with learning from these kinds of failures.


I hate that you're right. I wish experience wasn't such an expensive teacher.


I love that quote, it reminds me of a similar one:

>If you think education is expensive, try ignorance.


I feel like we are doing that right now. We had our Age of Enlightenment. I feel like we are heading for Dark Ages 2.0.


I worked in the same office as a nuclear safety expert. One day he mentioned all the issues with why Chernobyl melted down. I can't remember the details (pulled the rods partly out then re-inserted?), but I think the summary was that the people on shift were inexperienced and did everything wrong every step of the way. People in general knew how to manage reactors safely, the corners cut by a communist regime made it unsafe. Sadly, I don't have any sources, and I'm open to refutation.


The most critical issue was probably the reactor design's positive void coefficient. The RBMK design was created to use less enriched fuel than other designs, so it had to have performance characteristics that would permit a stable reaction when that fuel was used. To get that "feature", the design had a positive void coefficient.

This meant that it to work in such a way that reactivity would increase if coolant boiled away or other voids (spaces without nuclear moderating materials) formed in the fuel assembly. To keep reactions under control, it was necessary to ensure that there was always some material present to moderate the reaction.

Almost every other reactor design will essentially shut itself off if coolant is lost (negative void coefficient). This is a safety factor in case situations unexpected by the designers occur. In the event something really strange happens, the reactor turns off.

With a positive void coefficient, if something unforeseen by the designers happens, the reactor ramps up to higher output. Combine that with human mistakes in a certain sequence and safety systems that don't operate 100% correctly when the reactor is overheating and running away and you can get an out of control excursion as happened at Chernobyl.


It's one of the most studied disasters in history, but basically the main causes boil down to:

1. Personnel who didn't understand the risks of deviating from written procedure

2. Engineers who didn't anticipate or underestimated certain failure modes and didn't design the reactor and monitoring systems with sufficient redundancy and failsafes

3. Grossly insufficient monitoring systems

4. Denial at every level once it was obvious that something was Seriously Wrong


The failure modes were already known before the disaster. They were kept secret from the rank-and-file reactor operators and supervisors, as the Soviet regime was loathe to admit they were imperfect in any way.

The monitors and failsafes were there. Maybe could have been better, but they would have worked had they not been disregarded and deliberately overriden.

It was completely preventable. RBMK reactors of the same design are still operating safely today.


Also the reactor design was flawed - the control rods that should have stopped the reactor actually increased the reactivity while moving down into the reactor. Energy spikes were observed in different plants when shutting down the reactors, but they were classified to not show the reactor design (and by proxy the soviet union) in a bad light, so the operators had no idea of this critical fault.


We’ll, one of the corners cut was in the design of the control rods, and the Soviet government hid that from the operators. Did they screw up? Sure, but they did so believing — having been told — there was a fail safe that simply did not work as advertised.


Your understanding is mostly correct.

The issue with the fuel rods is that they were double purpose - the lower portion actually increased the reaction rate, while the upper portion decreased it. Because the team had manually fully retracted the rods, both portions were outside the reactor vessel. When it scrammed, the first portion to enter the vessel was the lower portion, which counterproductively increased the reaction rate further. This was one of several poor design choices in RBMK reactors.

You are correct that the people on shift did everything wrong at every step along the way - alongside management, who pushed forward the safety test that caused the accident on a skeleton night shift who hadn't explicitly prepared for it. The test deliberately had the reactor operating in an unusual, low-power state because it was supposed to test whether you could use momentum still in the turbines to bridge a gap until emergency diesel could be brought on line in the event of a power failure affecting the pumps that circulated coolant water to the reactor. However, the shift let the power in the reactor get too low, starving the reaction, and then took increasingly dramatic steps to attempt to bring the power back to specified (low but not that low) levels. These steps included disabling automated control of fuel rods, decreasing the rate of coolant flow, the removal of 18 of the 28 'fail-safe' control rods which were never to be removed, and disabling most of the automated scram mechanisms. Obviously, these steps were not normal procedure and constituted serious flaws in judgement.

Normal procedure would be to shut down completely when power levels drop that low, and then a waiting period and a several-hour-long startup procedure. The extremely low power state allowed a phenomenon called xenon poisoning to build up, which made restoring normal operation difficult - hence the normal procedure to shut down completley and allow the xenon to naturally decay. The attempt at restoring power despite this condition led to very unstable neutron flux, and with it unstable core temperatures, triggering alarms from several systems that were continually ignored.

Finally, the flaw in the design of a positive void coefficient (meaning that as heat goes up, water turns to steam, and the presence of the steam causes the reaction to become more efficient and produce more heat, in a runaway) actually struck, as the unstable neutron flux presumably spiked and the coolant flow was already further decreased (they had started the actual test, so the coolant pumps were being powered only by leftover momentum in the turbines). In combination, large steam voids formed, and then thermal runaway, and then a scram that actually first increased reaction rates further. (And then fuel rods fractured and many control rods got stuck at only 1/3 insertion, with the increasing portion still within the reactor). The void coefficient is why the test was supposed to take place around 700 MW, not the ~200 the operators had managed to restore; above around 700 MW the void coefficient in RBMK reactors is negative and such a runaway would not occur.


It's the nature of the beast, not the regime. If you read the NRC or other detailed reports on Three Mile Island, it was a non-stop litany of design flaws and making the wrong decision at every step.


I guess the price for communism, corruption, mismanagement, censorship it way higher than nuclear energy.

But, hey what do I know, experienced Chernobyl when it happened.


I remember all the vegetables etc. thrown away / not eaten in Germany back then - especially mushrooms (not vegetables, not animals I know) if I remember correctly.


Sheep farmers in Wales were still being affected by this in 2012, with testing performed on lambs and restrictions on which could be sold and which land they could be raised on due to radioactivity in the soil and hence grass.

https://www.bbc.co.uk/news/uk-wales-17472698

Just to put this in perspective, the affected part of wales in something like 1,500 miles from Chernobyl. I would guess some freak of the weather conditions caused Wales to be badly affected.


It was the prevailing winds at the time. The sheep in the Yorkshire Dales were also culled for a while, as I recall.


Yes, they were just unlucky that's where some of the rainclouds broke.


As a result of the Chernobyl accident, Mushrooms and wildlife feeding on them are still showing elevated levels of radioactive Caesium-137 in the Bavarian Forest and other parts of Bavaria. These levels are still monitored closely, even though they aren't considered dangerous anymore. Still, they are beyond the levels required by food safety standards.


All I got to say is the Japanese are really lucky the wind wasn't blowing onshore during the meltdown.


It wasn't that: The Fukushima reactors didn't contain graphite moderators that started to burn. In Chernobyl, this graphite fire carried fuel and fission products high into the atmosphere.


I remember having to drink powdered milk instead of regular milk for months afterwards. I thought it was very unpleasant.

Apparently there was fallout on the grass that cows would eat, resulting in radioactive milk?


It sounds like they are afraid of a criticality accident

https://www.nrc.gov/docs/ML1220/ML12205A469.pdf

For the most part a critical mass that produces enough heat to expand will have the reaction stop because the expansion causes the surface area per reactive nucleus to increase and the neutrons leak out.

It's unlikely that a situation like that will produce enough energy to be dangerous far from the reactor (an explosion or "meltdown") but it sure is dangerous for workers in the vicinity.


Your description sounds like it would spread lots of radioactive dust though. Which is bad for both the people on site and everybody downwind from the blasted thing.


It will make some more fission products, not much compared what it did in its life.

I can't believe it will make enough heat to damage the structure or disperse radioactivity directly.

If the neutron flux means that people can't go near the structure to maintain it then in the very long term you have more risk that the roof leaks, water leaks out, other paths of leakage don't get closed.

Really they should scrape up the corium (like they did at TMI) and put it through reprocessing like any other nuclear waste. The risk of a criticality accident doesn't make that any easier.


Largely off-topic, but still interesting:

https://en.wikipedia.org/wiki/Radiotrophic_fungus

I still find it fascinating that there is a fungus that lives inside the remains on Chernobyl and thrives in the radiation.


Damn nature will really use any source of free energy it can huh


You are what happens when sunlight shines on a rock with water over time.


I was going to suggest ammending "a lot of time", but it's only "a lot" to us. To the history of the universe, it is just a few shakes of a lamb's tail.


Thanks, learned it is useful in spacesuit to reflect radiation.


I wonder how big of a spike in streaming HBO's mini-series will see after posts like this. I know I'm suddenly intersted in re-watching it. The court room scene at the end was so good.


Does anyone know what radiation levels a commercial robot like Spot can handle, and what would be involved in shielding one to do jobs inside the sarcophagus?

Is it as involved as replacing all the electronics with hardened components, or could you just make a lead suit to cover it sufficiently? Not sure how the sensors etc. function in that environment.


That scientist brave enough to be a so-called 'stalker' at least deserves name recognition, shouldn't they?


I couldn't find any more information about the person mentioned in the article, but I did find more information about "stalkers": https://slate.com/news-and-politics/2014/09/the-stalkers-ins...


Reading the article I now suddenly understand why this game is called what it is:

https://en.wikipedia.org/wiki/S.T.A.L.K.E.R.:_Shadow_of_Cher...


... and the game combines Chernobyl and

https://www.imdb.com/title/tt0079944/

or

https://en.wikipedia.org/wiki/Roadside_Picnic

... or both, depending on how you look at it.


The Metro books and games also use "Stalker" in a similar sense


Yeah except Roadside Picnic was published in 1972 and basically invented the term.

From wikipedia:

The term "stalker" became a part of the Russian language and according to the authors, became the most popular of their neologisms. In the book, a stalker is a person who breaks the prohibition, enters the Zone and takes out artifacts from it, which they sell as a living. In Russian, after Tarkovsky's film, the term acquired the meaning of a guide who navigates forbidden and uncharted territories; later on, fans of industrial tourism, especially those visiting abandoned sites and ghost towns, were also called stalkers.



I wouldn't be surprised if they took it as part of their "day job".

Vadim - "Oy Aleksei, we are getting Neutron spikes in Sub basement 4A"

Aleksei - "Ah noi, eh cheeki breeki, iv damke"


I can't imagine many countries having an Institute for Safety Problems of Nuclear Power Plants.

It's too bad their job is a long-standing one.


Kinda off topic, there were like 3 submissions from sciencemag.org making the front page in the last 48 hours?

While I don't remember seeing the site that often in the past.

Someone's back reading the entire site and posting the interesting bits? :)


OP here. In my case, I just saw someone I follow for COVID news tweet about it and shared the link here.


I'm not complaining about you posting it, it's pretty interesting if you ask me. Just noticed there's a new site linked to from HN (which has its darlings).


> Because water slows, or moderates, neutrons and thus enhances their odds of striking and splitting uranium nuclei, heavy rains would sometimes send neutron counts soaring

How do slow neutrons have higher odds of splitting a nuclei? I'd have thought the exact opposite: faster neutrons--therefore, having more energy--would increase the odds.


The term splitting an atom seems like hitting a bunch of billiard balls to cause the atom to fly apart. What really happens is you want the atom to absorb the neutron and its kinetic energy so as to make the atom's energy higher than the strong force's ability to hold the it together. If the neutron's kinetic energy is too low, the atom will just absorb it. It may become radioactive and decay over time, but not necessarily in a speedy chain reaction way; however, going too fast isn't good either. Atoms become inelastic the higher the neutron's energy. If it's too high, the atom is effectively transparent to the neutrons and won't capture them. So, a "neutron moderator" slows the neutrons to an energy that is low enough to allow capture and fission, but not capture and no fission.


A fast neutron is more likely to cause fission, but much, much less likely to interact with a fissile nucleus in the first place.


Meaning, they will pass-through, as if the nucleus didn't exist?


Just a random thought. What would happen if you dumped nuclear waste in a volcano? Would that burn it off or cause an explosion?


You have the problem of potential eruptions sending it off everywhere.

Nuclear Waste has heavy elements that are dangerous specifically because they're radioactive. The heat might accelerate their half-life decay rate but it doesn't "burn" the atoms.


We don't know any non-nuclear process that can accelerate the decay of nuclei, so that should not be possible to change anything about that!


There’s some experiments that indicate ultrashort and high energy laser pulses may accelerate decay but not a lot of interest has been allocated to it.


Ultrashort and high energy.. are you sure we're not getting into gamma rays and nuclear physics with that? I guess by definition we are, if it has an effect :)


I doubt the heat in volcano is enough that change anything at the nuclear level. Heat is just motion of atoms/molecules. The temperature has to be high enough for the atoms to undergo high-energy collisions.


So tossing it in wouldn’t cause an eruption or burn off the radiation. But if the volcano erupted then it could send radiation everywhere.

Interesting.

Is research being done to try figure out safer disposal of nuclear waste?


Really the safest means of disposal is to bury it, but that is fraught with its own problems.


If the spent fuel were contained, you could first run it through a breeder reactor[0] to reduce volume by an order of magnitude or two. The remains are still highly radioactive, but now you have much less volume to deal with.

I assume that the waste in Chernobyl is largely/entirely distributed and contaminated with sand, dirt, other various debris, and thus probably couldn't benefit from that.

[0] https://en.wikipedia.org/wiki/Breeder_reactor#Waste_reductio...


The best solution is to bury it on land that is already more irradiated than any more added nuclear waste would make it. There is plenty of land like that.


Safest or cheapest? And on what time scale? Because the safest long-term means of disposal is to launch it into the sun, but that's prohibitively expensive and is short-term extremely dangerous (e.g. the rocket exploding or crashing shortly after lift-off).


I did wonder if dumping waste in subduction zones has been looked at.


What about launching it into space?


Rockets are not 100% reliable--having one carrying radioactive waste explode on launch would make for a really nasty mess to clean up.

Ultimately, the total volume of Radioactive waste ever created is tiny in the grand scheme of things. Burying it is not a technical problem. The problems are entirely political. This is also why breeder reactors don't make sense. They're trying to apply a technical solution to a political problem.


> Burying it is not a technical problem.

it is. the problem is that it needs to be stored way longer than any human is living. basically there are very few sites which might be able to withstand a timeframe so large without every polluting the environment. you know just burying is not enough, you need to be sure that no water or anything else might break your containments. it's probably impossible to do it and it's also not a good idea to think that burying it and forgetting about it is a good idea either.


Things that are radioactive for longer than human lifetimes are not very radioactive at all. The danger is more that they are still poisonous.

Finding places where you can control the groundwater isn't that hard. We have many candidates. Old salt mines are preferred because the salt slowly flows around the containers and entombs them. This is where the relatively small volume of the radioactive waste is a feature, you don't need a massive number of old mines to handle all of the waste. One or two would be sufficient.

Most of the concern about this is people demanding solutions that are grossly more complex and elaborate than the problem really demands. A political problem. Imagine if coal mines had to treat their tailings with the same level of care? They are similarly radioactive after a few years and just as poisonous, but we let them be dumped right into streams. Natural gas is extracted by pumping poisonous chemicals into the ground to break up rocks--greatly increasing the possibility of groundwater contamination. Imagine if they had to extract all of those chemicals back out of the ground and then store them someplace where they could be proven to never leak out again.

High level radioactive waste doesn't stay high level for very long by its very nature. This is why nuclear power plants have ponds where they store the hot stuff until it cools down enough for long term storage. After that they just have to be handled like any other nasty industrial chemical, plus some extra shielding to protect the workers from hitting their total yearly exposure limits too quickly.


> Things that are radioactive for longer than human lifetimes are not very radioactive at all. The danger is more that they are still poisonous.

good, so we take it out after 50 years and place it in your yard than? just kidding, but saying such things is stupid, the stuff is still highly dangerous even after > 1000 years, especially if the shielding gets blown away, people die from that. the fuel NEEDS to be on site for the first 10-20 years, since it's impossible to shield it good enough. after that it needs to be stored 100000 years at a minimum.

> Finding places where you can control the groundwater isn't that hard. We have many candidates. Old salt mines are preferred because the salt slowly flows around the containers and entombs them. This is where the relatively small volume of the radioactive waste is a feature, you don't need a massive number of old mines to handle all of the waste. One or two would be sufficient.

good idea. in germany we already found a salt mine: https://en.wikipedia.org/wiki/Asse_II_mine oh... wait.

btw. you can actually recycle some material, but that is expensive and is not done for all material, but it drain more billions of dollar for a single plant, most often it's easier to socialize the storage of the radioactive waste.

> High level radioactive waste doesn't stay high level for very long by its very nature

spent fuels is radiotoxic over 100000 years? I mean, that is long. of course for more money it can be reprocessed, reducing the long livity waste by a far margin and also not everything needs to be stored that long. it's still problem and down talking it does not help.

> Natural gas is extracted by pumping poisonous chemicals into the ground to break up rocks--greatly increasing the possibility of groundwater contamination. Imagine if they had to extract all of those chemicals back out of the ground and then store them someplace where they could be proven to never leak out again.

ok, because that's also bad it's ok to use another bad technology? heck coal is also bad it produces flying ash, way way more tones than all reactors in the world will produce over their lifetime. does it make the waste of nuclear better? no. is it good to point fingers on other technologies that are as bad? no. (to make it clear high level waste per 1000MW reactor is like 3m^3 (around a tonne) per reactor. of course it's not a lot compared to stuff that coal, mining (uranium gets mined, too and produces a shit ton of tailings) and gas, etc..., but a lot for the timeframe it needs to be stored)


After 50 years most nuclear waste is barely above background. I wouldn't want it in my yard because it's poisonous, not because it is excessively radioactive. Another way to think about this, uranium ore is in the water supply right now in some parts of the world. It's just about as radioactive as 100 year old waste and yet somehow people are managing to survive.

According to the Wiki that Asse II mine has not released radioactivity into the environment? It was maybe not the best choice given that the mine had been prone to flooding even when it was operational, but it's a manageable problem.

Dropping nuclear is exactly about using the other bad technologies. Renewables are slowly coming online to help, but for the most part you shut down a nuclear plant you open 4 natural gas plants in its place. Unless you are China, then it's 4 coal plants.


Once spaceX start launching from pads at sea I wouldn't be surprised if this was an option... load a rocket with really nasty stuff and fire it at the sun.

I bet Elon would do a massive discount for that.


I mean, you seem to be asking in earnest, so I'll answer. Still, the question is silly. Of course research is being done on this. Google is your friend.


"There are naive questions, tedious questions, ill-phrased questions, questions put after inadequate self-criticism. But every question is a cry to understand the world. There is no such thing as a dumb question." - Carl Sagan


Well I know we are researching how to /use/ nuclear waste. I believe that’s what one of bill gates projects is trying to do. But I donno if we have just decided burying it is it and that’s it.


The thing is, reusing nuclear waste is possible, but too expensive in the end, compared to renewables. I think there was 4 research reactor that did that in the world, and Russia launched a new one recently.

I still think nuclear must be part of the solution NOW (for an effect on CO@ in 2030 and on climate drift on 2050). Nuclear in 50 year will be too late. And i don't think nuclear is "the best", nor do i think that it isn't dangerous, nor do i think we should stop with renewables. Nuclear is a crutch and should be used as such.


"Burn it off"? What would that even mean? Burning is a chemical reaction. It doesn't alter nuclear processes that matter here.


The heat of the volcano wouldn't change anything. The problem is first that you can't guarantee it won't be carried on magma currents and be pushed above ground elsewhere, and second if it got stuck and didn't sink into Earth's core, you'd have a volcano dirty bomb just waiting for the next eruption. And you'd have no way of knowing if it got stuck or not.


Related: "Why Don't We Throw Trash in Volcanoes? " => https://youtu.be/Q1blQRrM4TA


Volcanic eruptions on the one hand and radioactive waste on the other are bad enough - no need to combine both.

Basically nothing would happen except that the radioactive materials would be dispersed among the environment.


When I was a kid I thought that launching nuclear waste into the sun was a decent idea. Now, not so much!


Into the sun would be fine.

Launches would be risky, though, and it's easier to send off to deep space instead. An out-of-the-solar-system orbit is cheaper energy wise than an into-the-sun one.


Right, the sun would obliterate anything that got close. The risks of the containers falling back to earth from a failed launch are significant.

Launching into deep space reminds me of the drill instructor in the game Mass Effect: https://www.youtube.com/watch?v=6q1IaWLsyrQ


It would be a pretty good idea if it didn't require such an insane amount of delta-v to deorbit a payload into the sun.


We just need to lift it there with a space elevator and then nudge it into the sun.

And then in a few thousand years we will be kicking ourselves for incinerating incredibly valuable resources.


It is less delta-V to launch something out of the solar system than it is to drop it into the sun.

Assuming you're not worried about nuclear waste leaving our solar system and becoming a problem for others, it makes absolutely no sense to launch it into the sun.


> becoming a problem for others

That seems a bit optimistic of a problem to have. Space is incredibly huge. For someone to accidentaly bump into it would have odds so huge I don't even know how to aproximate it.


There's no such thing as 'nudging' it into the sun. If you don't push hard enough, it will enter an orbit that coincides with earth's. And to push it hard enough you basically have to get it going away from earth at the speed earth orbits around the sun, which is quite fast.

Anything less, and it will be in an orbit that floats close to the sun then floats back up towards earth, more or less forever.


I think that we're going to need a bigger space elevator, then.


It's just being converted to solar :)


wouldn't you only need to deorbit if you "missed"? it's not like we're trying to safely land on the surface of the sun. we don't need it slow down at all, just aim straight for the middle and accelerate in.


As Earth is in orbit around the sun, everything launched from Earth automatically is also in orbit around the sun. To go into the sun, you need to deorbit from that orbit. Earth's orbit around the Sun has an orbital speed of about 30 km/s, so you need to cancel that to drop into the sun.


It doesn't have to get there fast. So what would the effect of putting up solar sails to create some drag to slow down? Wouldn't need heavy fuel to generate delta-v. Would the expense of a system to deploy/unfurl a solar sail cost more than fuel powered thrust?


Aside from the practical concerns with solar sails, there's a fundamental problem with using them to get to the Sun. To lower your orbit, you need to exert thrust in the retrograde direction (directly opposite to the direction you're going). However, that's perpendicular to the direction of the sunlight you receive, so a solar sail cannot generate any thrust in that direction!


once you've negated the delta-v, reel in the sails or detach them or whatever. at that point, Sol's gravity should do the rest. i'm sure some smart people with slide rules could determine when to do it to not be influenced by Venus/Mercury on the way in.


> once you've negated the delta-v

My point is that you can't cancel out the velocity of your orbit around the sun using solar sails.


So if you had the sail at a 45 degree angle to the sun, bouncing the photons forward to your orbit, wouldn't that eventually slow you down? Or do you get pushed outward into a slower orbit at the same time and cancel it out?

It's all a moot point anyway since solar sails are so ridiculously impractical that this would basically never work in real life regardless.


What about using mass drivers instead of chemical rockets?


Theoretically, sure. Practically we've entered science fiction territory here.


Yeah, I figured we did once we started talking about solar sails and space elevators.


Up next is just let the thing hang out in orbit around the sun at 1AU waiting for one of these "near miss" asteroids to come wizzing by so we can "catch" it with a net and let it drag our trash to the inner reaches of the solar system.


Mercury or Venus would be a better easier and cheaper alternative if the plan is to bury this garbage. Even the moon could be a better storage for the next two thousand years than anywhere in the earth.


You could put it near a subduction zone and wait for it to be pushed under a neighboring tectonic plate.


Maybe the heavy atoms would sink into the mantle.


Volcanoes are places where magma upwells to the surface, so they'd have to be so heavy they were able to sink against that upward flow. Very unlikely.


Seems like a silly idea, but thinking about it more deeply I'm not so sure. Uranium is almost 7 times as dense as even the densest magma, so it _should_ sink in theory. The only issue I can think of is that "maybe" isn't good enough when you're talking about risking a large amount of radioactive waste getting spread out over a large area in a volcanic eruption if it turns out you're wrong. But if we could figure out a way to do it reliably... maybe?

Another potential issue: is getting rid of nuclear waste _permanently_ really such a good idea? What if we discover some other use for it in the future?


There have been serious proposals to put a bunch of nuclear waste in a tungsten sphere, add a few sensors, and use it as a probe into the earth as it melts through the mantle.


> Elephant’s Foot was so hard scientists had to use a Kalashnikov rifle to shear off a chunk for analysis. “Now it more or less has the consistency of sand,”

Interesting how that changed.


Also interesting is the fact a rifle was/is used as a field instrument:

"The substance proved too hard for a drill mounted on a motorized trolley, ... Finally, a police marksman arrived and shot a fragment of the surface away with a rifle. The sample revealed that the Elephant's Foot was a solidified mass of silicon dioxide, titanium, zirconium, magnesium, and uranium"

https://en.wikipedia.org/wiki/Elephant%27s_Foot_(Chernobyl)#...


Probably made for a fun "methods" section in the resulting paper.

"Uh... we shot the nuclear waste. With an AK-47."


Sand is usually at the bottom of these containment vessels right? I wonder if that has something to do with it.


I think it's more likely that this is the result of radioactive decay. As elements decay, what was once a tiny piece of crystal or glass would develop defects. Among other reasons, the decay products will have different chemical properties from the original elements--so one atom may fit neatly into the structure 35 years ago, but today it's a completely different element, with a different number of valence electrons and a different size. The structure is fixed from 35 years ago when the core melted and cooled.

Imagine what would happen to your Lego buildings if some of the bricks got smaller or larger, changed the number of bumps, or split into two bricks.

Note that we're not just talking about metals here. For example, an element in a nuclear reactor might be a transition metal, an alkali metal, a halogen, or a noble gas at different points in the last 35 years--with radically different chemical properties.

I am definitely not an expert, but I did take inorganic chemistry and nuclear chemistry in college.

(Note that some of these changes in naturally occurring minerals, and the presence of compounds like noble gases trapped in minerals, are used to date minerals... you can estimate how long ago the mineral melted and cooled.)


Pretty wild to think about how something we take for granted as never changing in daily life can actually change in human lifespans to things as fundamental as atoms and isotopes. Sure, there's radioactive decay but few interact with this.

It's really like a big mess of uncontrolled alchemy of matter shifting around at chernobyl. I know it's a actually a giant mess of nuclear chemistry going on with all sorts of unknown distributions and spatial proximities of various atoms but wild to think about.

Typically this stuff is well controlled and reactor configurations are well established as are the types of reactions and byproducts produced with fairly high certainty. Take those very detailed designs away and you have no idea what sort of materials are shifting states in these globs of materials. They have designs and can reason basic percentages of what may have ended up where but lots of guesswork and lots of those are not highly refined materials I'm sure, which means a bunch of impurities are incorporated in as well.


Funny you say that this stuff is "typically" well-controlled in a reactor, because the imbalance between different decay products and the lack of control was a major factor in the Chernobyl disaster (which is admittedly atypical).

For example, one important fission product in a nuclear reactor is xenon-135, which is produced from the decay of iodine-135, which is a product of nuclear fission. When you run the reactor, it produces iodine-135, which has a half-life of 6.6 hours, producing xenon-135.

Xenon-135 is a "nuclear poison." It is the the strongest known neutron absorber, and it absorbs neutrons in the reactor that would otherwise be used for fission. While the reactor is operating normally, the reactor neutrons will "burn off" the xenon-135, and the fission products will produce new xenon-135, and you can run these reactions in equilibrium.

If you turn a reactor off, the xenon-135 builds up to higher levels--remember, takes hours for the iodine-135 to decay. Because xenon-135 inhibits the reactor, you have to either wait for the xenon-135 to decay (9.14 hour half-life) or you have to pull out the control rods to compensate.

The Chernobyl operators turned the reactor off (not on purpose), xenon-135 built up, and then they pulled out the control rods to start it back up. When the reactor finally started up, the xenon-135 was burned off by the neutrons in the reactor, but this happened quickly, and the control rods were still out.


This is compounded by the fact that the boron control rods at Chernobyl were tipped with graphite (to increase volume/displacement at lower cost), so that when the reaction started to run away as the Xenon built up, the operators attempted to SCRAM, but the graphite tips on the leading edge of the control rods acted as neutron moderators before the the boron was in place, further accelerating the reaction and causing the reactor explosion.


"as the Xenon built up" should read "as the Xenon burnt off*"


>Pretty wild to think about how something we take for granted as never changing in daily life can actually change in human lifespans to things as fundamental as atoms and isotopes. Sure, there's radioactive decay but few interact with this.

Steel rusts. Masonry turns to sand. Wood rots.


It's called "radioactive spallation" I think. The high radioactivity plays fast and loose with all kinds of molecular bonds, even in inorganic materials.


Radioactive spallation is a part of it, but it's not the process I was talking about.


They also dropped tons and tons of sand on the reactor core. I didn't read anything of sand below the reactor, so. My understanding is that they had two bio shields of concrete and some water tanks under the reactor.


I guess once Corium melts through that it becomes more glass than sand.


Given advanced applications in both unmanned remote control and boring machine technology and better economics, I wonder if we could get Elon Musk's view on tunneling down as far as possible below the reactor, and then tunneling up under it, to drop the remaining material deep into the deepest shaft ever dug into the earth.


We need a Godwin's law for Elon vs. all of society's problems.

"As the technical discussion gets more popular, the likelihood of Elon having a purported solution approaches one"


I don't understand how anyone could look at what Boring Company built in Vegas and conclude "these people are the best in the world to manage the Chernobyl cleanup."


That's actually really funny and point awarded. But the substance of boring beneath Chernobyl would still seem to bear some consideration, no?


Of course, why not? I'd be surprised if it wasn't considered. I just probably wouldn't bother The Musk with it.


Let us see how long it takes for HN to start praising nuclear power and shrug of any risks in this thread! :)


Nuclear power is so unsafe, ugh! I mean if it weren't for...

- Designing and building reactor that is demonstrably and knowingly unsafe by its own creators and other scientists

- Building it in the cash starved near collapse Soviet Union in a satellite state

- Having technicians carry out tests that are known to be unsafe for the sake of it

- Lying and attempt to cover up the issue because your entire power structure is all about saving face

What am I saying? Of course Chernobyl would've still happened!

I'm not particularly invested in if nuclear power is good or bad but holding up Chernobyl as a snarky "watch as the nerds ignore THIS!" is a herring so unimaginably red that it beggars belief


What's changed about bureaucracy and decision-making in government that makes it safe now?

Should only collapse-proof nations build nuclear plants? If it looks like a collapse is coming, should they decommission them early?

I get the better tech arguments-- those are solid. But this idea that they were dumb and we're smart is, I guarantee you, the same exact idea they had at Chernobyl. The whole reason they wanted to save face so much is because the whole thing was built on that idea.


By all accounts, the person running Chernobyl was a complete idiot. They disabled multiple safeties (including ones that would have averted the meltdown), then tried to make it output more than it was rated for (directly leading to the meltdown).

The same could be said for Boeing, etc., but that doesn’t mean we need to abandon air travel. We just need better leadership in safety critical organizations.


> this idea that they were dumb and we're smart

The cold war suggests Russia is anything but dumb. And as those bullets demonstrate, they where smart enough to know better - but the problem with the Soviet Union was not that it collapsed (or was unstable), but that it wasn't transparent - it cared more about the image of functionality than actual functionality.


Ahah, exact!

To have credit, you have to look good. To look good, you have to hide the bad under the mantle and show how much you can do with so little! In a way, soviet russia was more productivist than any company ever was and will ever be.


I'd imagine military is one of the most bureaucratic organizations one can have, yet the US Navy has been operating nuclear powered vessels for quite some time.


Is it better if those corrupt bureaucracies use coal instead, thus necessitating the consumption and handling of around 1000000x as much fuel?


Because one person purposely drives off a cliff, following orders, we ban biking. Despite its usefulness and that the situation was contrived. Right

There are a lot of ways governments can harm the environment on purpose using tools that are generally helpful.


It's safer than most of the alternatives yes, and it works better than the safer alternatives

https://ourworldindata.org/safest-sources-of-energy


It would be like saying that hydro is bad because of the 1975 Banqiao Dam failure, an accident way worse than Chernobyl by most metrics.

Like all energy sources, there are risks and there are solutions to mitigate these risks. And I don't know any sane proponent of nuclear energy that think that we should ignore the lessons learned.


If we're going to judge nuclear by its few accidents and not overall safety for the past 70 years compared to, say, mining coal, sure.


Coal miners tend to die later when they're retired (at least in more modern times), it's not so visible as to create fear. And people directly affected by coal smoke pollution aren't even counted. Again, this doesn't create enough fear.

Same for airplane accidents vs car accidents.


Since you brought it up, no, Chernobyl is not a good example of the risks of modern nuclear technology.


Chernobyl is a good "line in the sand" to develop the safety precautions around (for example, assume Chernobyl happens, what things prevent long-lasting harm).


That’s like assuming the manager of your grocery store will kill everyone with an automatic rifle, then designing the building for easy cleanup.

We know how to build safe nuclear plants. We should do that, and also make sure there’s enough independent oversight to make sure they’re not being managed by people actively trying to melt them down.


You'll be glad when someone drops a load of watermelons in aisle three.




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