[HN Gopher] Finland's plan to bury spent nuclear fuel for 100k y...
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Finland's plan to bury spent nuclear fuel for 100k years
Author : giuliomagnifico
Score : 55 points
Date : 2023-06-16 13:31 UTC (9 hours ago)
(HTM) web link (www.bbc.com)
(TXT) w3m dump (www.bbc.com)
| plastic3169 wrote:
| There is nice arty documentary film "Into eternity" about Onkalo
| (made already 2010)
| https://www.youtube.com/watch?app=desktop&v=ayLxB9fV2y4
| cmcaleer wrote:
| There's also this Tom Scott video on it:
| https://www.youtube.com/watch?v=aoy_WJ3mE50
| pierat wrote:
| What I don't get is the following:
|
| If your nuclear waste is that "hot" (highly radioactive), then
| you're not draining as much energy out of the material.
|
| Ideally, the closer to lead you are, the more energy is drained
| out. And that's what I'd hope to see from the mining required for
| uranium. Instead, we seem to run it once and then go "whoop have
| to stop".
| acidburnNSA wrote:
| Not sure I'm following. Fission reactors split uranium into
| smaller atoms like barium and krypton. The remaining energy
| that comes out as afterglow heat in the repository is a small
| fraction of what already came out during fission. less than 1%
| remains an hour after fissioning.
| nabla9 wrote:
| You have the numbers reversed.
|
| In spent nuclear fuel 96% of the mass is the remaining
| uranium is still usable. Spend nuclear fuel (=LEU) used in
| these reactors have almost all potential energy left.
|
| You can use them if you close the nuclear fuel cycle with
| fast neutron reactors. The downside of it is that they FNR's
| are also good for making fuel for nuclear weapons.
| acidburnNSA wrote:
| I don't have the numbers reversed. I'm talking about when a
| single atom actually undergoes fission, it releases 93% of
| its energy promptly as fission product kinetic energy,
| gamma rays, and neutron kinetic energy. An hour later,
| another 6% of the energy goes out as delayed betas and
| gammas. After that, only 1% remains to emerge as heat in
| the repository.
|
| What you're referring to is the fact that some reactors
| (aka breeder reactors, fast or thermal) can fission a much
| higher percentage of the total atoms loaded into the
| reactor, including most of the majority isotope (U-238) in
| addition to the minority (U-235).
|
| I wrote a bit about breeding and recycling here:
| https://whatisnuclear.com/recycling.html
| phkahler wrote:
| >> don't have the numbers reversed. I'm talking about
| when a single atom actually undergoes fission...
|
| Well then maybe you should talk about the problem at
| hand, which is the stuff people are considering "nuclear
| waste" and wanting to bury.
| pfdietz wrote:
| That 96% of the mass is 238U. It's usable in breeder
| reactors. It's not useful for today's burner reactors. We
| have far too much 238U for those already; enrichment is the
| process of stripping out 238U from natural uranium. It
| would be utterly pointless to recover more 238U for them.
| We already have great stockpiles of depleted U sitting
| around. The stuff is not worth very much right now.
|
| Reprocessing can recover some plutonium, which can be
| reused (once more) in MOX fuel. Spent MOX fuel cannot be
| reprocessed further for use in today's thermal reactors,
| though.
| Out_of_Characte wrote:
| Yeah, you could reprocess spent fuel but one of the byproducts
| would be plutonium. So we'd rather bury everything than using
| the plutonium for other projects because of fear that we can't
| handle nuclear byproducts.
| phkahler wrote:
| I see what you did there.
| rektide wrote:
| This was one of the advantages of Integral Fast Reactor. It
| had on site pyroprocessing, which doesn't have the same
| nuclear proliferation risks. https://en.wikipedia.org/wiki/Nu
| clear_reprocessing#Pyroproce...
| photochemsyn wrote:
| There are three issues with trying to get more energy out of
| hot 'spent' fuel rods
|
| (1) the radiation levels increase, making it more dangerous for
| workers to do maintenance and safety operations (so overall
| reactor design would need to take this into account),
|
| (2) some fission products and transuranics (plutonium etc.) act
| as neutron poisons (absorbing neutrons rather than generating
| energy-productive fission events), resulting in reduced reactor
| output and instability issues as the accumulate in the fuel
| rods.
|
| (3) since you are actually transmuting elements, physical and
| chemical changes take place resulting in fuel rod corrosion and
| degradation, swelling and structural changes, etc. which could
| lead to catastrophic failure by clogging the reactor core and
| preventing coolant circulation.
|
| [edit] note that reprocessing the spent fuel (plutonium
| recovery) for use in MOX reactors is possible, but since this
| is also how you run a nuclear weapons program, there are
| additional concerns and the costs are really high:
|
| https://world-nuclear.org/information-library/nuclear-fuel-c...
| pfdietz wrote:
| If we're burying spent fuel, that's a tacit admission that
| nuclear will not be powering the world, because a once-through
| fuel cycle with thermal reactors (like the ones used in Finland)
| powering the world runs out of cheap uranium very quickly.
|
| In any case, the lack of a geological repository for commercial
| high level waste in the US is mostly because there's no
| stakeholder who really needs it. Storing spent fuel in dry casks
| is a perfectly cromulent solution -- and that waste could be
| buried or reprocessed later (more easily, after it cools more) so
| this doesn't rule out any other solution.
| soulbadguy wrote:
| > the world runs out of cheap uranium very quickly.
|
| Citations ?
| pfdietz wrote:
| World uranium resource information is readily available. For
| example:
|
| https://world-nuclear.org/information-library/nuclear-
| fuel-c...
|
| gives a resource, as of 2017, of 8 million tonnes. Note that
| the recent expansion in uranium exploration didn't increase
| the resource very much.
|
| A 3000 MW(th) thermal burner reactor uses about 250 tonnes of
| natural uranium per year.
|
| https://material-properties.org/what-is-natural-uranium-
| cons...
|
| To "power the world" (by which I mean provide, as heat, the
| 18 TW of current world primary energy consumption) would
| therefore require 6000 x 250 or 1.5 million tonnes of natural
| U per year.
|
| It has long (like, since shortly after WW2) been known that
| powering the world with fission will require some kind of
| breeding, which implies some kind of reprocessing. If you are
| committed to that, burying spent fuel as is makes no sense.
| pfdietz wrote:
| There's a question of how cheap "cheap" has to be. But
| saying "uranium cost doesn't matter because capital cost of
| the power plants is so much larger" is a left-handed
| argument.
| thumbsup-_- wrote:
| 100k years. Reality is that in 50 years the fuel will start
| leaking and then the cost of securing the vicinity/repairs will
| be too high for anyone to bear. Govt will try to ignore
| scientific warnings while some politicians will criticize the
| govt for not doing anything while others will say it's a waste of
| money. After some pressure, the govt will start repair work but
| in a few years the cost of repairs will be 3-10x the original
| estimates and with no signs of leakage stopping. After another
| 5-10 years, the govt will decide to pull the plug and a blame
| game will begin.
|
| So, to summarize, we are not the species that can really plan for
| 100k years and have the conviction of maintaining those plans.
| mikrl wrote:
| The ancient Egyptians couldn't bury their royalty for 10K years,
| but I applaud this engineering project and hope it goes well for
| Finland.
| Moldoteck wrote:
| I don't get something so maybe somebody can explain. Afaik,
| France has nuclear reprocessing plant, basically they take used
| fuel, separate nonrecyclable parts and get new fuel to be used
| again in their reactors. Why other countries don't send their
| used fuel to France for reprocessing? Is it too expensive? Too
| dangerous to transport? limited capacity of the plant? Or that
| the produced fuel can't be used in reactors from other countries?
| Also, why don't other countries build similar plants?
| Symbiote wrote:
| See the start of https://en.wikipedia.org/wiki/La_Hague_site
| chrisbrandow wrote:
| " The digital emissions from this story are an estimated 1.2g to
| 3.6g CO2 per page view"
|
| I'm a little surprised that the emissions are so high per page
| view. I've never looked at co2 emission calculations for web
| pages before, but this seems a little high.
| ilyt wrote:
| napkin math on
| https://www.eia.gov/tools/faqs/faq.php?id=74&t=11
|
| 0.855 pounds/0.38kg of CO2 per kWh.
|
| or 0.38g per Wh
|
| so 3.6g would be ~9.4 Wh, let's assume 10Wh
|
| Site takes ~700ms to render, . So it would need to consume the
| equivalent of over 5kW of compute for a second to get that
| amount of CO2 per view.
|
| That assuming it would be 100% load, and not just "waiting on
| various network RTTs"
|
| I think it's safe to assume it's pure bullshit, even including
| every device along the way
| penteract wrote:
| It's including the amount used by your machine while viewing
| the page, so if you're using a desktop with a 500W PSU (and
| you're using all 500W, which is probably an overestimate) and
| you spend a minute reading the article, that's 30kJ, which is
| roughly 1/2 a gram of methane[1], so roughly a gram of CO2
| (more if it's coal, more if you take into account the fact that
| generators don't capture all the energy as electricity).
|
| [1]https://en.wikipedia.org/wiki/Methane#Combustion
| acidburnNSA wrote:
| I'm excited that Onkalo will be coming onine soon, so we don't
| have to hear the myth that there's no solution for spent nuclear
| fuel anymore. The solution that enjoys a solid scientific
| consensus is the deep geologic repository.
|
| Another thing that is weird to me is that everyone says nuclear
| waste is hazardous for a uniquely long time, but it become less
| hazardous over time. Many non-radioactive materials, like arsenic
| and mercury, are toxic forever.
|
| In the US we have WIPP operating, but it stores weapons-related
| radioactive material rather than commercial spent fuel, so I
| guess it doesn't count.
|
| https://en.wikipedia.org/wiki/Waste_Isolation_Pilot_Plant
| SoftTalker wrote:
| Arsenic and mercury came out of the ground, originally. It's
| not like we can make those elements from scratch. Diluting them
| and putting them back where we got them is probably fine.
|
| Nuclear waste _is_ something new we are creating, but I 'd
| rather have it deep underground in a geologically stable place,
| than sitting in casks on the surface.
| belorn wrote:
| Mining is not exactly a natural process. We can't dilute the
| toxic byproducts and putting them back where we got them,
| since that would require rebuilding the mountain. In cases of
| open mines, all that is left is a lake size hole where solid
| land once where.
|
| What the mining industry do is to fence it up (including
| pools used for waste), put up a sign to warn people, and then
| let nature fill it up with water. The best we can hope for is
| that they did their research properly and made sure that it
| doesn't leak into the groundwater.
|
| In the past there were people who tried diluting stuff like
| this by dumping it into the ocean, but that isn't the best
| idea.
| PinguTS wrote:
| Burying things in the ground is not a solution. It's more an
| Ostrich policy.
| omginternets wrote:
| Do you prefer venting it to the atmosphere? That's the
| alternative for producing substantial amounts of energy
| _reliably_.
| shawabawa3 wrote:
| burying is absolutely a solution, especially when nuclear
| fuel is so dense you can store all the waste of humanity's
| power needs in a relatively small area
| sofixa wrote:
| Better in the ground that the air.
| acidburnNSA wrote:
| Lots of scientists disagree strongly with your statement.
|
| "The conclusion that disposal is needed and that deep
| geologic disposal is the scientifically preferred approach
| has been reached by every expert panel that has looked at the
| issue and by every other country that is pursuing a nuclear
| waste management program."
|
| https://www.energy.gov/ne/articles/blue-ribbon-commission-
| am...
|
| One thing that drives me craziest of all is when people
| simultaneously claim that nuclear waste is among the most
| hazardous things out there while also blocking any progress
| to get it safely out of the biosphere.
| StanislavPetrov wrote:
| >The conclusion that disposal is needed and that deep
| geologic disposal is the scientifically preferred approach
|
| The parent post didn't say that burying the waste wasn't
| the scientifically preferred approach. Disposal is only
| needed if you create it in the first place.
| PinguTS wrote:
| The thing is, that to human knowledge it is currently the
| only viable way to handle the situation. But still it is
| not a solution.
|
| A solution would be to make it non-hazardous. But there is
| no viable way to do it right now.
| pdonis wrote:
| _> to human knowledge it is currently the only viable way
| to handle the situation._
|
| No, it's not. See comments elsewhere in the thread about
| reprocessing.
| aPoCoMiLogin wrote:
| highly recommended to watch
| https://www.youtube.com/watch?v=4aUODXeAM-k
| phkahler wrote:
| How about we reprocess it and use it as nuclear fuel. IIRC
| France is the only country that does this. We just don't
| like the kind of reactor needed.
| pdonis wrote:
| _> IIRC France is the only country that does this_
|
| No, many countries do:
|
| https://en.wikipedia.org/wiki/Nuclear_reprocessing#List_o
| f_s...
| pdonis wrote:
| _> by every other country that is pursuing a nuclear waste
| management program._
|
| This claim is simply false. Many countries reprocess
| nuclear waste:
|
| https://en.wikipedia.org/wiki/Nuclear_reprocessing#List_of_
| s...
| acidburnNSA wrote:
| Countries that reprocess nuclear waste still need a deep
| geologic repository for the fission products and minor
| actinides due to process losses. Reprocessing reduces the
| number of repositories you need for a given fleet size,
| but you still need a repository.
| pdonis wrote:
| _> Countries that reprocess nuclear waste still need a
| deep geologic repository_
|
| That's possible, but even if it's done, it's only
| necessary for hundreds of years (because the radioactive
| isotopes left over have much shorter half-lives), not
| 100,000 years. Big difference.
| acidburnNSA wrote:
| Radiotoxicity does indeed drop to ore levels in 300-500
| years but even then there are a few problem actors.
| Partitioning and transmutation can help with these,
| probably.
|
| https://en.wikipedia.org/wiki/Long-lived_fission_product
| pfdietz wrote:
| I consider the elements containing those isotopes to be
| prime candidates for space disposal, not burial.
| pfdietz wrote:
| That list includes the US, which hasn't had commercial
| reprocessing in many decades.
|
| The truth is that reprocessing is an economic loser at
| this point; even France admits it. Separated plutonium
| literally has negative value; you lose money trying to
| fabricate fuel elements from it instead of using freshly
| enriched natural uranium. France still does reprocessing
| because whatever is done with spent fuel is not that
| expensive compared to the cost of just building and
| operating nuclear reactors, so the boondoggle is not that
| big.
| pdonis wrote:
| _> reprocessing is an economic loser at this point_
|
| Not on a time scale of 100 years or so, let alone the
| 100,000 years that are being imposed as a requirement on
| geologic storage. On that time scale recovering unburned
| fuel from reprocessing will be cheaper than mining and
| refining fuel.
|
| _> France still does reprocessing because whatever is
| done with spent fuel is not that expensive_
|
| Yes, particularly when you factor in that reprocessing
| gives you a source of additional fuel (most of the
| "spent" fuel removed from reactors is actually _not_
| spent, and reprocessing recovers it for future use) that,
| as noted above, is expected to be cheaper than mining it
| in the not too distant future.
|
| _> the boondoggle_
|
| It's not a boondoggle at all, it's a rational way of
| anticipating future nuclear fuel requirements, as above.
| It's certainly much more rational than requiring spent
| fuel to be stored for 100,000 years as if that was the
| only possible thing that could be done with it.
| pfdietz wrote:
| > Not on a time scale of 100 years or so
|
| AT THIS MOMENT it's an economic loser. If you need
| reprocessed fuel in 100 years, by the miracle of nonzero
| interest rates you save money by doing it closer to then
| instead of right now. The cost of storing the fuel until
| then is low enough that this works out.
|
| > It's not a boondoggle at all, it's a rational way of
| anticipating future nuclear fuel requirements, as above.
|
| No, it's a waste of money to do it right now.
| pdonis wrote:
| _> it 's a waste of money to do it right now_
|
| If you're allowed to store the current waste in a
| facility that's only good for 100 years or so, then yes.
| But not if you're required to store any waste you don't
| reprocess for 100,000 years.
| pdonis wrote:
| _> That list includes the US, which hasn 't had
| commercial reprocessing in many decades._
|
| But it also includes many countries that reprocess
| currently.
|
| The US has not reprocessed fuel in many decades, and
| never on any significant scale, because the Carter
| Administration outlawed it based on mistaken concerns
| about proliferation, and it's been a political pariah
| ever since. It has nothing to do with any rational
| technical assessment.
| pfdietz wrote:
| Pakistan and India do it for their nuclear weapons
| programs. You don't want to be making that argument.
|
| The UK, France, Japan, and Italy don't reprocess anymore
| (I'm not sure Italy ever did on any substantial scale).
|
| Carter stopped reprocessing by executive order, but
| Reagan quickly reversed that order. No reprocessing then
| occurred, because reprocessing made no economic sense. It
| turned out Carter's order isn't what killed reprocessing
| in the US; cold hard economics did. It did provide a
| convenient excuse for those who wish to ignore that
| reality.
| pdonis wrote:
| _> Carter 's order isn't what killed reprocessing in the
| US; cold hard economics did._
|
| No, "cold, hard economics" would say, if you are correct
| that it's not even cost effective to do _any_
| reprocessing now, that the spent fuel should be stored
| for 100 years or so and _then_ reprocessed, when it 's
| economically cost effective.
|
| But US policy has been that spent fuel has to be stored
| in a facility that's good for 100,000 years. That makes
| no sense if the waste is going to be reprocessed 100
| years from now. It makes sense only as part of a
| political scheme to kill nuclear power altogether. Which
| is exactly what it was, even if on paper reprocessing was
| "allowed" after the Reagan administration.
| ScoobleDoodle wrote:
| I think the people you're referring to want us to stop
| producing nuclear waste in the first place.
|
| This approach of geological sequestration, while being the
| scientifically preferred solution, still has potential very
| negative consequences for some future generation many years
| in the future. By some people calling this safe, it enables
| the nuclear proponents to leverage that to say there is no
| issue with the waste so it's fine to create more.
| StanislavPetrov wrote:
| > By some people calling this safe, it enables the
| nuclear proponents to leverage that to say there is no
| issue with the waste so it's fine to create more.
|
| Unfortunately those who believe nuclear energy generation
| is necessary often refuse to acknowledge the very real
| risks and costs associated with it. The fact is that
| there is no panacea when it comes to energy generation.
| All known methods come with risks, rewards and downside.
| It is fine to argue that nuclear energy is the cleanest
| and safest way to generate energy, but not that it is
| completely safe or without risk.
| lesuorac wrote:
| I mean we could treat it like a coal power plant and just
| dilute the radioactive material into the air instead.
| linksnapzz wrote:
| Burying things securely until a better solution can be found
| is a better than letting them sit onsite in storage pools...
| phkahler wrote:
| But may not be better than shutting it all down.
| linksnapzz wrote:
| Sorry, I like reliable electricity, I don't live near a
| hydro plant, and I'd prefer not to burn coal. Nuclear
| does what I want, and if the desire for a perfect
| solution for waste handling gets in the way of a good
| method for keeping the lights on while we work towards
| improving the isolation and transmutation of waste-that
| desire needs to be set aside.
| PinguTS wrote:
| I agree to in way that this is currently the only viable
| way to handle the situation. But it is not a solution.
| linksnapzz wrote:
| "Live in Idaho" isn't _THE_ solution to deaths from
| tropical diseases; but let 's not pretend that it isn't
| _A_ solution...
| this_user wrote:
| "Securely" being the key term here. Something that is
| buried securely today may not be buried securely tomorrow,
| or in 100 or a 1000 years, because the geology of the
| planet is not static. This can become even more of a
| problem if the knowledge should be lost what was buried
| where.
| linksnapzz wrote:
| The subterranean geology of granitic shield provinces
| doesn't change much over the course of ...human-
| accessible timescales.
| iso1631 wrote:
| As Ostrich policy is ignoring the problem -- specifically not
| looking at the problem. Burying the Geiger counters would be
| an Ostrich policy
| acidburnNSA wrote:
| Exactly.
| PinguTS wrote:
| It is exactly that. We are putting it deep into the ground
| and ignoring the problem.
| wkat4242 wrote:
| Yeah exactly like us not worrying about all the CO2 30
| years ago "because the atmosphere is so big mankind
| couldn't possibly make a change"
|
| We should balance ourselves with nature now instead of
| dumping it on the future.
|
| This way we're solving the CO2 problem the way a gambler
| solves their debt by borrowing more money to pay off
| loans.
| circuit10 wrote:
| If it doesn't cause any problems when it's underground
| then that's just called solving the problem
| iso1631 wrote:
| My guniea pigs hide from predators by burying themselves
| in hay. It's fairly effective.
|
| That's not what as Ostrich does. An Ostrich leaves itself
| exposed and just closes its eyes.
|
| Mankinds attitude to all sorts of threats is an ostrich
| policy, but burying nuclear waste is not one of those.
| Leaving it in a barrel and saying "nothing to see here"
| would be.
| mastax wrote:
| Why not? What specific problems does it _not_ solve?
| roughly wrote:
| Stewart Brand has an interesting take on this in Whole Earth
| Discipline (which is quite a read) - this is energy we don't know
| how to use yet. In 100 years, we'll be digging this stuff right
| up again, because there's energy in there. I'm not typically as
| utopian - techno or otherwise - as Brand, but I agree with him
| here - the nuclear industry is less than a century old, and we've
| already got a pretty good idea how to get enough energy from this
| fuel to not have a 100k year problem to begin with. Kicking the
| can down the road a couple decades might actually be the right
| thing to do here.
| gtvwill wrote:
| Less common side of the argument a friend presented to me. We
| shouldn't use nuclear in mainstream use cases now because we
| don't harness enough of its power. We're basically depleting a
| future fuel supply before we even know how to use it properly.
| It has more value to us in the future when utilization is at
| higher %.
|
| Personally not sure which side of the fence I sit on. It
| definitely has benefits now, but we also have capacity to make
| do with other shit. If we make do with other stuff will we
| forget about it and never get to that higher utilization point?
|
| I found it an interesting point. Wouldn't be the first time
| humans have made something extinct/disappear/rare before the
| true value of the thing is understood.
|
| Use now with low efficacy for mild gains. Save for future with
| bet on higher efficiency and increased gains.
| jupp0r wrote:
| There's also the opportunity cost of not using nuclear fuel
| right now, instead burning fossil fuels and incurring all the
| irreversible long term damage that comes with it.
| cultofmetatron wrote:
| the problem that argument is that we learn how to increase
| efficiency as a result of using it and building a supply
| chain around that resource. Just look at gas engines. a
| modern gas engine uses a fraction of the fuel of a model T to
| transport more weight faster to their destinations. What
| you're suggestion would be akin to saying we should avoid the
| model T and wait till the prius is available. without a car
| industry, we wouldn't have ever gotten the R&D to have a
| prius in the first place.
| wkat4242 wrote:
| Once we're that much more capable we'll be doing fusion which
| requires different elements for fuel anyway.
| jwestbury wrote:
| How interesting, I was just reading about this in the context of
| nuclear semiotics and how to pass down warnings about the danger
| of nuclear waste. (This is a really interesting topic without
| much in the way of clear answers, depending on what you're
| optimising for. Highly recommend reading the Wikipedia page[0] at
| a minimum.)
|
| There's apparently a documentary on this project, "Into
| Eternity," released in 2010, which has been on my list since
| earlier this morning (i.e., since I read about its existence).
|
| 0. https://en.wikipedia.org/wiki/Long-
| term_nuclear_waste_warnin...
| mongol wrote:
| Since the fuel will be encased in copper, and copper is quite
| valuable, I see a future, some centuries or millenia from now,
| where people will try to steal it, without realizing the dangers
| associated. With bad side effects as consequence.
| credit_guy wrote:
| And how exactly will they know where to steal it from? Are they
| going to start digging random holes through bedrock just
| because they might hit treasure?
| voidfunc wrote:
| Eh, assumes copper will be valuable in that time frame.
| Unknowable.
| nabla9 wrote:
| The mechanical container solution is top notch, but 99% of the
| safety is just geological stability and selecting right place.
| Over 2 billion year old granite with very few cracks far from any
| fault lines.
|
| The worst possible scenario they calculated:
|
| 1) the nuclear canister would corrode in a thousand years instead
| of the calculated hundred thousand years,
|
| 2) and at the same time installed clay buffer surrounding
| canisters would inexplicably disappear.
|
| 3) In addition, the groundwater would magically flow upwards and
|
| 4) a city would be built on the site. A person who would live on
| the most polluted square meter from cradle to grave and would
| only eat food grown there and drink the most polluted water
|
| Result: people would only receive three times the radiation dose
| compared to people currently living in a city of Tampere.
| Ekaros wrote:
| I wonder if that area has Radon... Which likely would mean much
| higher dosage...
| elif wrote:
| Personally I'm rooting for the future where a fleet of falcon 9's
| launch escape velocity stage 2's that head straight for the sun.
|
| Underground is nice until you get radioactive groundwater. The
| time cost of 100k years of maintaining safety seems more than the
| financial cost of maintaining a F9 fleet and disposing of second
| stages.
| ttul wrote:
| My engineering students explored this idea for a project. It
| turns out that sending something into the sun is really
| difficult. You have to overcome the velocity of planet earth
| orbiting the sun, which means you need a delta-V of 8.8 km/s to
| get the waste into a high orbit above the sun, followed by
| another burn to reduce its velocity to zero at that orbit.
|
| That's the same delta-V as going to Jupiter. You would need a
| lot of rockets.
| spywaregorilla wrote:
| How many falcon 9's would that require?
| xnx wrote:
| "...it's surprisingly hard to actually go to the Sun: It takes
| 55 times more energy to go to the Sun than it does to go to
| Mars.
|
| Why is it so difficult? The answer lies in the same fact that
| keeps Earth from plunging into the Sun: Our planet is traveling
| very fast -- about 67,000 miles per hour -- almost entirely
| sideways relative to the Sun. The only way to get to the Sun is
| to cancel that sideways motion."
|
| https://www.nasa.gov/feature/goddard/2018/its-surprisingly-h...
| ilyt wrote:
| use solar sail to break into the sun ?
| elif wrote:
| I dunno about 55 times more...
|
| Earth escape velocity is 11.2 km/s or 25,000 mph in your
| preferred units.
|
| And you don't have to go backwards relative to earths orbit
| and cancel it out, you can maintain earths' solar orbit and
| degrade it.
|
| You only need enough energy to reach L1 and since human time
| scales are irrelevant you can do that as efficiently as you
| like. After you reach slightly past L1, the sun will do the
| rest of the work.
|
| At closest approach, Mars is 54 million km away. L1 is
| typically 1.5 million km away. Even ignoring the fact that
| human timescales are irrelevant, it is a significantly easier
| journey.
|
| You are probably thinking of speeds required to orbitally
| maneuver near the sun, as we typically do with instruments...
|
| A trip straight into the sun is substantially easier than
| mars.
| pfdietz wrote:
| Falcon 9s are still too expensive, especially if you want to
| armor the spent fuel in case of launch failure.
|
| Disposal of troublesome fission products and actinides, on the
| other hand, could be much easier. There are seven fission
| products with troublingly long half lives that would be
| difficult to retain in geological repositories. Extraction and
| space disposal of the elements of those isotopes could make
| sense.
|
| In any case, space disposal can wait until launchers are mature
| and the technology has stopped improving. We have centuries
| before spent fuel stops being self-protecting against diversion
| due to its radioactivity, so stick the stuff in dry casks and
| wait.
| pintxo wrote:
| How would this ever be acceptable, given that rockets have a
| failure rate that's not zero?
| acidburnNSA wrote:
| Everyone suggests throwing it into the sun until they think
| about this fact. Stable geologic formations are far
| preferable, by orders of magnitude, for this reason.
| simmerup wrote:
| The impossibility of getting an insurance policy to cover
| this downside probably makes it dead in the water unless a
| state starts doing it
| pintxo wrote:
| Didn't stop us from using fission for energy production.
| But weapons production might have played a relevant role
| here.
| kuratkull wrote:
| Kurzgesagt: "Why Don't We Shoot Nuclear Waste Into Space?"
| https://www.youtube.com/watch?v=Us2Z-WC9rao
|
| Bad idea, it boils down to 1) too much of it (yes really, in an
| almost definitive sense) 2) exploding rockets + nuclear fuel is
| bad
| iso1631 wrote:
| An Atlas V can get 400kg to the nearest star (well any star) by
| launching on a solar escape velocity -- see New Horizons. An
| expended F9 has a similar payload I think.
|
| You'd have to construct a container that would survive a
| failure - so an explosion of the rocket (on the pad or during
| launch), or a failure in LEO where it would have reentry. That
| container would then need to be able to be recovered no matter
| where it landed on that failure -- so things like floating
| would be important, and some form of control over landing so it
| didn't crash onto someones house. Or in an inconvenient
| country. Obviously it has to stay in one piece.
|
| Now sure, much of that shielding doesn't need to go beyond LEO,
| but it leaves very little room for the actual payload.
| lm28469 wrote:
| Until one of them fails to launch or reach orbit
| fwlr wrote:
| I do think the borehole plan (3km deep, rather than 400m deep) is
| better, although it is more speculative and this proposal has the
| overwhelming advantage that it's being enacted.
| karaterobot wrote:
| Agreed; perfect is the enemy of the good in this arena. We just
| need someone to do something first, to make it easier for the
| second group, and the third, who can then offer some
| improvement to the process without having to overcome the same
| level of NIMBY challenges.
|
| NIMBY may not be the right acronym. Not In My Very Remote,
| Geologically Stable Bunker System.
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