The US needs to figure out what to do about its radioactive garbage:
Lindsay Krall decided to study nuclear waste out of a love for the arcane. Figuring how to bury radioactive atoms isn't exactly simple—it takes a blend of particle physics, careful geology and engineering, and a high tolerance for reams of regulations. But the trickiest ingredient of all is time. Nuclear waste from today's reactors will take thousands of years to become something safer to handle. [...]
[...] Congress has shown little interest in working out a solution for future generations. Long-term thinking isn't their strong suit. "It's been a complete institutional failure in the US," Krall says.
But there's a new type of nuclear on the block: the small modular reactor (SMR). [...] A Department of Energy-sponsored report estimated in 2014 that the US nuclear industry would produce 94 percent less fuel waste if big, old reactors were replaced with new smaller ones.
Krall was skeptical about that last part. "SMRs are generally being marketed as a solution—that maybe you don't need a geological repository for them," she says. So as a postdoc at Stanford, she [...] got an answer: By many measures, the SMR designs produce not less, but potentially much more waste: more than five times the spent fuel per unit of power, and as much as 35 times for other forms of waste. The research was published in the Proceedings of the National Academy of Sciences earlier this week.
Startups seeking licenses to build SMR designs have disputed the findings and say they're prepared for whatever waste is generated while the US sorts out permanent disposal. "Five times a small number is still a really small number," says John Kotek, who leads policy and public affairs at the Nuclear Energy Institute, the industry's trade association.
But the authors say the "back-end" of the fuel cycle, which includes waste and decommissioning, should be a bigger factor in what they consider to be the precarious economics of the new reactors. "The point of this paper is to prompt a discussion," says Allison Macfarlane, a former chair of the US Nuclear Regulatory Commission and a coauthor of the paper. "We can't get to how much it is going to cost until we understand what we're dealing with."
[...] She believes both US regulators and the vendors themselves should be doing more to anticipate how waste will be handled before the reactors are approved and built to anticipate and factor in the costs. The SMR industry looks brightest to her in places that are doing a better job of figuring out long-term storage, she adds, pointing to Finland, Sweden, and the United Kingdom. "The real issue is that the US doesn't have a plan for its spent nuclear fuel," Macfarlane says. "I'm not feeling optimistic right now."
Journal Reference:
Lindsay M. Krall et al., Nuclear waste from small modular reactors [open], PNAS, 2022. DOI: 10.1073/pnas.2111833119
(Score: 2, Interesting) by Anonymous Coward on Monday June 06 2022, @07:38PM (9 children)
Nuclear reactors to generate electricity have always been best done as large baseload generators. if you're going to go to the hassle of having to deal with nuclear power in the first place, you might as well get **a lot** of gigawatts out of it.
(Score: 1, Insightful) by Anonymous Coward on Monday June 06 2022, @08:55PM (8 children)
Is larger more efficient?
(Score: 0) by Anonymous Coward on Monday June 06 2022, @09:28PM
Yes.
(Score: 2) by unauthorized on Monday June 06 2022, @10:00PM (6 children)
Thermodynamic machines are a lot like penises - bigger is always better until you start hitting physical constraints. The amount of useful energy you can extract from a generator is limited by the temperature difference from the environment, so the hotter your system is, the more energy you can theoretically extract. However eventually you're either going to be leaking too much heat because there is no such thing as perfect insulation or your reactor chamber will melt.
(Score: 1, Insightful) by Anonymous Coward on Monday June 06 2022, @11:15PM (5 children)
Temperature difference ΔT I'll agree on. I was asking about total size. Is a 2-4 GW reactor more efficient than say a 50 MW one? And if so, how/why?
(Score: 5, Informative) by c0lo on Tuesday June 07 2022, @01:11AM (4 children)
The larger, the more fuel and moderator, the higher the chances for a neutron to get thermalized (and lose some energy as heat) then hit some other fissile atom and generate another link in the chain reaction.
In a smaller volume you leak neutrons in the containment vessel walls and the fissile fuel gets transformed into energy at low efficiency. Add the more intense neutron bombardment of the containment and cooling systems making the targets more radioactive and you get (TFA quoted)
https://www.youtube.com/watch?v=aoFiw2jMy-0
(Score: 0) by Anonymous Coward on Tuesday June 07 2022, @04:01AM (1 child)
Wow, thank you. That makes sense. Are you a nuclear engineer?
(Score: 3, Interesting) by c0lo on Tuesday June 07 2022, @05:05AM
Bachelor degree in physics, long way back. Switched to software engineering very soon after graduation, tho.
https://www.youtube.com/watch?v=aoFiw2jMy-0
(Score: 3, Interesting) by Spamalope on Tuesday June 07 2022, @02:48PM (1 child)
Also this isn't like other types of power plant. Fuel isn't the primary cost. Safety, engineering, regulatory compliance, construction and practicality are. So make them bigger until you hit a size constraint. Then... standardize designs as with aerospace. Iterate the designs, but not a new '1 of' prototype every single power plant.
And... spend on this like we did on Nuke weapons during the cold war. Our reactor designs are based on weapons tech as that's where the money was spent, and power utilities don't have the cash to develop the tech privately. Lets invest in power plant specific tech to get something safer with a pre-planned fuel lifecycle. Possibly a real thorium effort (i.e. a fusion power level effort to push fission forward; if we'd done that first it'd have paid for a bigger fusion program in a walk then run way)
(Score: 0) by Anonymous Coward on Tuesday June 07 2022, @04:40PM
Fusion could not be replicated, and there is no currently accepted theoretical model that would allow it to occur.
(Score: 4, Interesting) by Snotnose on Monday June 06 2022, @07:46PM (28 children)
OK, I don't have any kind of degree in nuclear physics. But it seems to me if the waste is causing problems it is energy waiting to be harvested. Instead of encasing it in containers designed to last for thousands of years, howzabout we take that waste and keep making energy? From what I've read they turn nuclear fuel into nuclear waste when it's what, 2% consumed?
I mean, you've spent the time and energy making the gas, why throw it away after using only 2% of it's potential.
This would be a good time to point out I don't know shit about the economics of nuclear reactors, and wonder why there isn't more research into Thorium reactors (ooo oooo ooo! I know! Thorium won't go BOOM!)
I just passed a drug test. My dealer has some explaining to do.
(Score: 0) by Anonymous Coward on Monday June 06 2022, @07:59PM
Thorium is mostly hype at this point.
It's not a magic bullet that will solve nuclear's "problems."
We should just build conventional uranium powered reactors NOW and in quantity.
(Score: 0) by Anonymous Coward on Monday June 06 2022, @08:01PM (1 child)
You are right about the waste. The process is called "reprocessing" and hasn't been allowed in America since Carter disallowed it. Why? For the usual anti-nuke reasons.
(Score: 2, Interesting) by Anonymous Coward on Monday June 06 2022, @08:52PM
Had to protect OPEC and the petrodollar, and devalue the American dollar
(Score: 0, Insightful) by Anonymous Coward on Monday June 06 2022, @08:02PM (16 children)
The problem is twofold. Professional liars inventing FUD on Gazprom pay, and stupid clueless greenies believing their every word.
(Score: 3, Informative) by Anonymous Coward on Monday June 06 2022, @08:13PM (15 children)
Here and I thought the problem was that solar and batteries keep getting cheaper all the time, and nuclear keeps promising to get cheaper without actually doing it.
(Score: 0) by Anonymous Coward on Monday June 06 2022, @08:17PM (12 children)
Problem: the sun only shines half the time, and then not always brightly; sometimes the wind won't blow, and other times, it blows too hard.
But...
Nukes do it all night long.
Nukes are reliable, steady power.
(Score: 1, Insightful) by Anonymous Coward on Monday June 06 2022, @08:25PM (11 children)
Electrical grids are built around "peak load", they need to deliver power when it is needed the most. By a happy coincidence, electricity is needed the most when the sun is shining (to power all kinds of equipment that only runs during the day, especially air conditioners, which only run during hot days.)
People go on about how nuclear is good for base load in a way that solar is not, ignoring the fact that base load is not the problem that most needs solving.
(Score: -1, Troll) by Anonymous Coward on Monday June 06 2022, @08:30PM (10 children)
Solar power is not reliable, nor is enough produced to satisfy demand, as solar requires a lot of acreage for modest power output. Were it not for "conventional" electrical power sources to fill the gaps, renewables could never happen.
(Score: 5, Informative) by c0lo on Tuesday June 07 2022, @02:57AM (9 children)
Here, all conservative estimates that shows you can potentially get about 80-90% of energy demands without losing a square inch of acreage.
Most suburb homes in US can accommodate 15kW PV at full Sun on their roof and a battery large enough to buffer their daily production (minus self-consumption). In average of a day you get the equivalent of at least 4h of full Sun (integrating cos(φ) over -π/2 to π/2 gets you 2. Rescaling to a 10h daylight, gets you 2*10/π = 6.36h. But, OK, clouds happen, lets take it only 4h-full sun equiv per day)
Approximating to 50% of US population living in suburbs [bloomberg.com] and taking 2.6 persons in average per household [pewresearch.org], you get around 63 millions of suburb homes.
Assuming all have 15kW PV and a battery to buffer over night, will results in a total energy generated/day to 4*15*63e6 kWh/day = 3780e6 kWh/day = 3.78 billion kWh/day.
Total U.S. electricity consumption in 2021 was about 3.93 trillion kWh [eia.gov] which gets you 10 billion kWh/day.
You get a potential about 40% of your daily energy needs only from PV panels on suburban roofs without any acreage being lost, with the suburbanites being net producers of energy and covering almost in full those total 4.054 billion kWh/day residential consumption for the entire US population (1.48 trillion kWh for total residential consumption in 2021 [eia.gov] = 4.05 billion kWh/day residential consumption)
And I haven't included in this Walmart & other commercial supermarket roof space, nor the roof surface of airports or warehouses or industrial buildings, not even the surface of open parking space that one can convert to light undercover parking with PV on top [bloomberg.com]
Ooops, only suburban roof space + parking-under-PV-cover gets you to 80% of your energy needs, no loss or repurposing of acreage.
What's even better, you gain resilience - with a distributed energy production and a good percentage of consumption taking place close to where it is produced, the risk of some hacker (or nukes) taking off your entire grid goes down.
https://www.youtube.com/watch?v=aoFiw2jMy-0
(Score: 2) by RS3 on Tuesday June 07 2022, @04:18AM (8 children)
Thanks for all of that, and good to have you here again. I can't and won't try to argue with your excellent numbers. What I do know is that I did some work for a small company installing some PV systems ten-ish years ago (USA). The company owner is (also) a BSEE and MBA (who now works for Amazon doing major project management). He was up on all the numbers, and most systems we installed were in the 5 - 10 KW range. They were sized based on the residence's needs, and generated as much as the residence used per day / really per year. Sun angle, clouds, rain, snow, etc., all accounted for. These were fairly reasonable size houses (and a few commercial jobs too).
At the time I asked why not make them bigger. It seems a no-brainer that there's a fair amount of cost overhead in having us come out and do the install. A few more panels would only cost a bit more. Boss man said that if you generate more than you use on average, you only get pennies (I forget the number) pay for the power. NOT the amount you pay the electric generation company, but maybe 5% of what they get. I don't understand the story behind that, but cynical me says it's all about the far far too strong of a connection between corporations and congress. Not sure how to fix that, but I've given it some thought for more than 20 years.
One of the projects boss man managed is all but covering Amazon warehouses ("fulfillment centers") with PV systems. I had the fun of visiting one. It's mind-numbingly huge.
I've said forever that especially commercial buildings- all of them- should have PV systems on the roofs. Added bonus: roof lasts much longer!
And now the ironic: boss man lives in a neighborhood with a (draconian) HOA (Home Owners Association) with rules and he is NOT allowed to put PV panels on his roof!
(Score: 4, Interesting) by c0lo on Tuesday June 07 2022, @05:03AM (7 children)
Happens to me too now.
As a consumer, I buy energy at retail price - which supports the income of the do-almost-nothing-most-of-the-time** energy retailer intermediary. The retail price I'm paying is 38c/kWh
As a producer, I'm paid a bit more than the average energy spot-market price (which is about $50/MWh or 5c/kWh) - I'm paid 8c/kWh.
Now, when you look at your (my) consumption, it's cost saving at retail prices, so you have chances for a decent time to RoI for the PV investment that just cover your consumption
Anything capacity over that will generate income only at open energy-market price and you'll be competing against the producers that do energy production in bulk for a living. Likely, you aren't going to recoup your investment in excess capacity by the time the PV-es are dead.
** the good thing they provide tho' is shielding from spot-market excesses. I don't know tho' if the "insurance against extreme prices" service is justified by the price I'm paying, but most of the retailers go with the same range of prices. In any case, my PV-es are close to 10yo and I recouped the money I paid for them so I intend to upgrade them and put on a battery buffer too.
https://www.youtube.com/watch?v=aoFiw2jMy-0
(Score: 2) by RS3 on Tuesday June 07 2022, @06:17AM (6 children)
Awesome post as always. Thanks mate. All makes perfect sense.
Yeah, I was thinking batteries too. I haven't done PV on my own house because I have much tree shade (which is good in and of itself) but there's some roof exposed. And in winter with leaves down I'll get power. I see people selling "used" PV panels for dirt cheap, so I might go that route. They're not as efficient as new, but the much lower cost will offset the lower output. Still looking into it.
In some US states energy (electricity) suppliers are required to generate clean power, or buy credits from people who do, including homeowners. It's a bit like a futures or stock market, where the values rise and fall, but it's a good thing for PV owners. More of that would help immensely.
(Score: 2) by c0lo on Tuesday June 07 2022, @08:06AM (5 children)
Beware: the shadow of a simple stick can drop the efficiency of your solar panels by 20% [youtube.com].
Has to do with the fact that even slightly shadowed panels/cells aren't able to generate the full voltage the the others "peers" expect and start functioning as a load to them.
Without bypass diodes, the shaded cells will overheat. With bypass diodes (which is the norm nowadays), entire rows of with shaded cells or even the entire panel is shunted out.
https://www.youtube.com/watch?v=aoFiw2jMy-0
(Score: 2) by RS3 on Tuesday June 07 2022, @08:58AM (4 children)
Oh yeah, most assuredly if they're missing Schottky diodes, I'll solder them in. :)
Now you've got me wondering about inverter efficiency. Our first installs were typically 3 "strings" in parallel, of 7 - 12 panels per string, all into 1 big inverter. Later installs used "micro inverters"- 1 or 2 panels per inverter. My hunch is the 1 big one should be slightly more efficient. The many small inverters allow you to discover weak, failing, or failed panels, and you have less loss due to small bits of shade. I dunno...
(BTW, the pedant department wants me to tell people they should be called "modules", and a "panel" is a group of modules. Seems silly, and I'm not sure I agree with the terms.)
(Score: 2) by c0lo on Tuesday June 07 2022, @11:06AM (1 child)
Ummm... yeah, apologies, I simply forgot that I was chatting with somebody that actually worked in the field. My only weak excuse, I'm after 11h of coding (and I still need another two to finish what I want today).
As for Schottky diodes... umm, have a look at these [digikey.com] - the fwd voltage (Vf)... jaw drop experience a few years back when I first saw it. A bit pricey, tho'.
https://www.youtube.com/watch?v=aoFiw2jMy-0
(Score: 2) by RS3 on Tuesday June 07 2022, @06:33PM
Oh, no worries mate! I figure others read these posts, so more info is good for all.
Somewhat embarrassed EE here- I had never heard of those "smart bypass diodes". That's some trickery to get a circuit to do that. Hmmm- looking at the TI datasheet- they have a "charge pump" inside to build up enough volts to power the internals. Very very cool. Price isn't too bad, considering. You don't need one per poly chip. TI are showing 3 per PV module, for example, so cost per module is pretty low. I like it and I'll use them if needed, thanks!
Oh, and Digi-Key is super awesome, very wide inventory, very fast delivery, but tend to be a bit pricey.
I know that "can't stop and go to bed" thing all too well. I've done some coding, and many other things where that's the situation. I think I'm being productive, and I just don't want to lose my train of thought and ideas. Sometimes, the next day I find I'm much more clear, look at something I did way too late in the day, and wonder what was I thinking? Oh, yeah, wasn't thinking, just going on adrenaline and mental momentum (at least that's how I see it).
(Score: 2, Interesting) by Anonymous Coward on Tuesday June 07 2022, @04:56PM (1 child)
i prefer micros. people can turn ev1l if money can be made:
1) each micro has its own "maximum power point (sic) tracker" for the single panel it is connected to.
2) the output is straight up grid AC. equipment for AC can be used.
3) one panel or micro dies, that is the loss.
4) one panel dies, buy ANY manufacturer (that falls into operating range of the micro) can be replacement.
5) one micro dies, same see 4)
6) you can place micro-panel all over the place. one here, one there...
7) hop before you fly or soar. you can get a combo of "micro, panel, and a wall-plug" for ... i dunno, half a iPhone? one combo is ~ 1kwh for a sunny day.
8) it's mostly the crapasitor ... er... capacitors that die in electronics. micros can be made with longer lasting crap..er...capacitors (>20 years).
a bunch of micros to get x watt cost more then one central string inverter a same x watt.
for string inverter, if it goes doodoo, none of the connected modules work.
if a string-panel dies, good luck finding a replacement that matches the other "old still working" ones.
hope the schrotty (lol) by-pass diode works as advertised (it makes the christmas-light electricity by-pass a shaded, broken or pooped on panel... hopefully).
this is amazing shit, give some love and a mppt tracker for each single panel already.
ah, also, if for whatever reason you need to rejiggle your setup, the legos...err... micros are the way to go and can be rearranged in more fashions (re-distribute over all AC phases if encountering a blocking ev1l meter. or remove some, place infront of storage battery, etc ...)
(Score: 3, Interesting) by RS3 on Tuesday June 07 2022, @06:15PM
Thank you, yes I know, agree with, and can confirm all that you wrote.
The micros we used were "potted" in epoxy, so replacing crapacitors not so easy. I have de-potted things, but it's not fun (boiling, chipping away, more boiling, more chipping, etc...) Chemical depotting will often destroy the components' packaging.
The big "string" inverters we used have been 100% reliable but I certainly agree that if it fails, everything fails.
(Score: 0, Interesting) by Anonymous Coward on Monday June 06 2022, @10:42PM (1 child)
Can anything get cheaper when corrupt politicians keep piling nuisance demands on it?
Same tactics are applied to domestic oil and gas these days. Those things magically get greener when imported, particularly from Russia.
As to solar and batteries "getting cheaper", start producing them first, you cretin. As things stand, the day the Chinese stop dumping them into your market, you all will be caught with your pants down.
And you have a tiny little problem right there. If produced in a civilized country, without slave labor, your solar and batteries will need another century of getting cheaper before approaching competitive. What a pity.
(Score: 2) by DeathMonkey on Tuesday June 07 2022, @03:12PM
Done!
US is the #2 manufacturer of batteries on the planet. Home to the largest battery plant on the planet as well with 37 gigawatt hours of production annually.
Mapped: EV Battery Manufacturing Capacity, by Region [visualcapitalist.com]
The US is still a massive manufacturing powerhouse. It's just that we use robots instead of humans for most of it these days.
(Score: 4, Interesting) by JoeMerchant on Monday June 06 2022, @08:32PM (5 children)
Need enough heat to make steam. Need less heat than will vaporize steel and concrete. So, there's a Goldilocks zone for electricity production from, well, any heat source.
Most radioactive stuff on the surface of the Earth doesn't get hot enough to make steam, at least not fast enough to be interesting.
Refine it, and it will. Refine it more and it will also make a blinding flash of light - outside the Goldilocks zone.
So, I suspect that the initial refinement step tries to keep it from going Chernobyl/TMI on you too easily, but still make enough heat to vaporize lots and lots of water really fast (Megawatts).
I also suspect that when the source has degraded to a certain point, it is more economically attractive to replace it with a freshly refined source than it is to continue using the worn out source.
I further suspect that refining raw materials from non-renewable mine sources is currently more economically attractive than handling waste material and refining it back into the Goldilocks zone.
Nuclear physicists could get all Periodic Tablely on you with which isotopes have alpha-gamma-beta decayed into what new meta-stable isotopes, etc. and there's probably a lot of that: like you don't want your Uranium to decay all the way into Radon, because radioactive solids are much easier to handle than gases - so best to be extracting all the X from the middle of that decay chain before you give everyone in the plant lung cancer, etc.
All in all, I'd much rather see the honest to God's own truth numbers breaking down how military purposed "boom stuff" waste is stacking up in comparison to civilian purposed "power stuff" waste in comparison to military "power stuff" waste like makes the submarines and aircraft carriers go... I do know there's a LOT of depleted Uranium laying around out there, enough that it's basically a negative cost resource: if you have a legitimate safe application for it, they will pay you to take it.
Україна досі не є частиною Росії Слава Україні🌻 https://news.stanford.edu/2023/02/17/will-russia-ukraine-war-end
(Score: 1, Informative) by Anonymous Coward on Monday June 06 2022, @08:43PM (1 child)
That's not how nuclear power or bombs work. You take a fuel material made of atoms that will easily absorb neutrons shot at them, they then split (producing 2 new atoms of a different element), and emit energy in the process, and also emit some neutrons. (You do need a small source of radioactivity to get the whole initial neutron shot at the fuel thing started.)
The part about emitting neutrons when the fuel atoms are split is how the reaction becomes self-sustaining. You control the rate of reaction in an electrical power reactor by controlling how many neutrons make it to fuel atoms.
(Score: 2) by JoeMerchant on Tuesday June 07 2022, @08:04PM
>You control the rate of reaction in an electrical power reactor by controlling how many neutrons make it to fuel atoms.
Which is essentially done by refining the material to a pure(er than found in nature) form and then putting neutron absorbing materials (e.g. control rods) into the material to control how much hot is happening.
Or, in the case of boom stuff, you get enough sufficiently refined material together to reach critical mass where the neutron generation builds asymptotically, with the associated asymptotic energy release rate.
I designed a (unintentionally oscillating) high power RC circuit that went asymptotic once the tech/intern who assembled it turned it on: 10W resistors can go Boom too (no injuries, that time) - quick review of the Spice sim showed a tiny sliver of asymptotic response in a part of the graph we hadn't looked at before - apparently a part of the graph we operated in. Oops, live and learn.
10kg of U-238 has soooo much more energy release potential than an electric circuit plugged into a 15A outlet, best to get the simulations right on those before handing them off to interns to build.
Україна досі не є частиною Росії Слава Україні🌻 https://news.stanford.edu/2023/02/17/will-russia-ukraine-war-end
(Score: 0, Disagree) by Anonymous Coward on Monday June 06 2022, @10:25PM (1 child)
You can't get more energy out of it than you put in to it. So there are very few reason you would spend the energy to make less radioactive material more radioactive just so you could extract the energy from it again - unless maybe you're into radioactive batteries?
(Score: 3, Informative) by khallow on Monday June 06 2022, @11:00PM
A vast amount of energy was put in before Earth even existed. That's the energy that gets pulled out each time the fuel is reprocessed.
(Score: 2) by DeathMonkey on Tuesday June 07 2022, @03:21PM
I poked around a little to try and answer that question and the quick answer is: It's complicated!
Apparently nuclear weapons waste is basically all liquid. They decided to dissolve the waste rods in acid for some reason so now we have a crazy amount of radioactive acid left over.
Power waste is kept in it's solid form because that makes it way the fuck easier to handle safely!
So you can't really do an apples to apples comparison...
(Score: 3, Informative) by c0lo on Tuesday June 07 2022, @01:26AM (1 child)
Waste is waste, mate. You won't get much energy back from the (now radioactive) steel of the containment vessel: given that steel is mostly iron, which is (one of) the most stable nucleus - if that becomes radioactive, sure as hell you get to consume energy to make it so.
Other radioactive waste (carbon, liquid sodium, whatever coolant/moderator you get to use) will also steal energy from you. It's a fission reaction, so if a carbon atom get split by absorbing a neutron, you'll get at least two particles with higher bound energy, so you again spent more energy than you get back. This without mentioning reactions in which a neutrino goes away with a chunk of your energy and you can do nothing to stop it.
https://www.youtube.com/watch?v=aoFiw2jMy-0
(Score: 0) by Anonymous Coward on Tuesday June 07 2022, @06:14AM
Most of the material in nuclear waste is partially burned fuel, which also happens to be the most dangerous part. This is due to the buildup of neutron poisons [wikipedia.org] which eventually shut down the reactor. Typical light water reactors only burn about 3% of their fuel before the rods have to be replaced, but even modern breeder reactors max out at about 6% burn. If the neutron poisons are removed [wikipedia.org] then the partially burned fuel can go back into the reactor to produce more power.
(Score: 0) by Anonymous Coward on Monday June 06 2022, @08:53PM (4 children)
*sigh* just don't do it.
more burn-up seems to make more waste, duh?
more enrichment % seems to give better extracted MW.day-per-kg (of stuff). tho, more enrichment is a "cheat"(?):
ThorCon 20.0% / burn-up 256 MWd/kg (graphite/NaF)
ABWRII 3.4% / burn-up 50 MWd/kg (water/water)
methinks anyway you toss it, if you abuse the fuel more you automagically get more resenting junk coming out.
having a low burn-up with low enrichment kinda still allows you to run to the melted-down reactor, shovel some stuff, walk back a few meters and die. the next guy won't have to go as far and might be able to move it away a bit further even before same fate.
with highly enriched and highburnup, the best you can do is run towards the meltdown and hope you got enough life left to throw the shovel in the general vicinity of the core, before you die very quickly ... which just turns it into a game of "who can throw the shovel closer to the melt-down"?
ofc we are not barbarians, there should be research. most on how to keep it out of the greedy hands of commercialism.
if we ever find some nuke-fuel on other (dead) planets , i don't see why we can't use it to jump-start the hopefully by then available alternative energy generators? so bring your "how to build a nuke 101" hand-book :)
as for research, alas, it will have to be a entity that doesn't need to outsource the manufacturing and is vertically integrated. you don't want to go chasing down who is responsible and start a blame game or get a run-around for a upgrade and/or improvements ://
as to why nukes are expensive, it's all in the "book-keeping", methinks. i think, that "money", also lovingly called fiat money, today, is a promissory note for access to energy, mostly oil.
if your book-keeping goes like that, then free-endless energy has no value or infinite value, since you don't need or can issue a promissory note for it in either case (trust in god to make it difficult).
so nukes are "a kind of infinite energy source" (who ever said "tooo cheap to meter" first, got a stern look from the book-keeping department, sure), so the energy coming out of it has no value, thus one tends to pre-charge the value into the building of the device.
thus the nuke "cost" as much to build as one expects the value of the generated "free" energy to be, so the crazy "promissory note" book-keeping" can continue.
so, for the people using this type of "book-keeping" a SMR is a gold mine. all other costs, are not "book-kept" and are costs of a different kind, similar how the exhaust of a gasoline or diesel vehicle has no cost in the books ... but other types of costs.
now off to my midnite nuke powered coffee machine, damn the costs.
(Score: 0) by Anonymous Coward on Monday June 06 2022, @09:47PM (3 children)
Better 'burn up' makes less waste because you don't need to replace the fuel rods as often. A modern reactor that gets 6% burn-up produces half as much waste per unit of energy produced as an old reactor that only gets 3% burn-up.
Enrichment produces significant waste (depleted uranium) and is only needed if you are using inefficient light water reactors. Modern breeder reactors don't need any enrichment, are more efficient, and can run on the stockpiled waste from the old light water reactors.
With decent reprocessing (currently illegal to even research) the waste is actually less radioactive than natural ore because the more radioactive parts go back into the reactor to produce more energy.
"Too cheap to meter" has always been nonsense. It's an easily disproved strawman used by the anti-nuke crowd.
(Score: 0) by Anonymous Coward on Tuesday June 07 2022, @03:15PM (2 children)
thanks for reply.
oh, i didn't know. i thought "burn-up" was just 'murikan slang for "bunch of radioactive stuff created".
so, translating " more burn-up" into non consumerism honest speak "more radioactive stuff created".
i was wondering how to interpret 20% enriched 256 MWd/kg
and 3.4% 50MWd/kg.
20 / 3.4 = 5.88
5.88 * 50 = 294
to me it seems less magical fissionable " fall-apart" ore is required?
(oh-naturel ore is a combo)
so excluding secondary neutron activation, -aka- making magic bricks for hogwarts, to get x amount of MWd, the lowly enriched one wins...thus leading me to conclude less of the original splitable atoms where harmed and turned into nasties?
(Score: 0) by Anonymous Coward on Tuesday June 07 2022, @03:46PM (1 child)
also on the topic of magic-speak in muggle land:
"carbon neutral" is magic speak.
in muggle land, carbon is neither asian nor indian nor arabic nor ... it is not pro or against abortion, neither "green" nor "greedy".
also there is not more or less of it tomorrow.
this is what you get when hiring wizards and witches. they have a hard time speaking muggle.
what they prolly wanted to convey is that muggles using energy (which today seems to involve alot of carbon) should measure how much energy they are consuming and measuring how much non-carbon-based energy they are producing (tho "harvesting" might be a more exact translation)
or there abouts. it's hard to talk to and understand wizarding folks sometimes :/
(Score: 0) by Anonymous Coward on Tuesday June 07 2022, @04:02PM
sumtimes i like to play wizard and don my wizard outfit from toys-r-us.
i would go around the neughbour hood, plastic wand in hand, uttering "zero energy production" and flick the wand at a house (tho i later shorten it to just "zero") and then go home, all smug about casting sucessfull spells as a muggle :P
(Score: 1, Offtopic) by Runaway1956 on Monday June 06 2022, @09:39PM (12 children)
We should just find a nice unused but active volcano somewhere. Dump all the waste into it. Problem solved, I think. (snicker)
Abortion is the number one killed of children in the United States.
(Score: 0) by Anonymous Coward on Monday June 06 2022, @09:57PM (9 children)
I was always partial to those proposals to put all the nuclear waste on a rocket and shoot it at the sun.
That's a really well thought out solution to dangerous nuclear waste.
(Score: 2) by DannyB on Monday June 06 2022, @10:31PM (5 children)
It requires a lot less delta-v to send all that nuclear waste to the far side of the moon.
How often should I have my memory checked? I used to know but...
(Score: 0) by Anonymous Coward on Tuesday June 07 2022, @01:32AM (4 children)
Not true, escaping Earth's gravity is the big delta-v, who cares how quickly the material would take to reach the sun? In space you don't need to worry about drag.
(Score: 0) by Anonymous Coward on Tuesday June 07 2022, @02:48PM (3 children)
yes, yes ... no.
once you leave earth orbit you automatically fall into another orbit.
if you go faster, your orbit increases.
if you break, go slower, your orbit decreases.
i made this thinking mistake too.
you see, standing here, still, meditating, unmovable on earth, you are full of enormous orbital energy 'cause the still ground, earth is WOOSHING at an enormous speed around the sun.
everything we launch, will not just slow down like a candy wrapper thrown out a moving car window "and fall into the sun".
in space, the candy wrapper now orbits the sun at that enormous WOOSH speed.
you have to undo, or break that speed in the OPPOSITE direction to reduce your orbit to get closer and closer to " fall" into the sun.
thanks so much kerbal space program i am happy i bought you on steam
(that shitty space craft is still only flying parallel to mars (no capture) *grumble*)
(Score: 0) by Anonymous Coward on Tuesday June 07 2022, @02:57PM
duuna? mars? watsthedifderence :P
(Score: 0) by Anonymous Coward on Tuesday June 07 2022, @07:15PM (1 child)
Going to the moon you already break out of Earth's orbit, planning a launch window so the rocket doesn't get near Mercury or Venus would be trivial.
With the moon orbiting Earth I'm sure there is some neat trajectory that could save fuel, but it wouldn't be much less than a trajectory into the Sun since the bulk is to get escape velocity.
(Score: 0) by Anonymous Coward on Wednesday June 08 2022, @04:14AM
Yeah no, no you don't. Go play ksp or CoaDE.
(Score: 2) by dwilson on Monday June 06 2022, @10:34PM (2 children)
Go spend a few hours with everyone's favourite orbital mechanics simulator, Kerbal Space Program. Then come back and tell us all about shooting a rocket at the sun.
Hint: Dropping anything in to the sun is impractical, horrendously energy-intense, and not a well-thought-out solution to anything.
- D
(Score: 1, Funny) by Anonymous Coward on Monday June 06 2022, @11:45PM
Whoosh! ;-)
The worst part of the rocket idea is the risk of the rocket exploding at some point and spraying nuclear waste into the atmosphere.
(Score: 1, Funny) by Anonymous Coward on Tuesday June 07 2022, @01:41AM
What if you used that waste to power a nuclear rocket then? See? You gotta work smarter, not harder.
(Score: 2) by PinkyGigglebrain on Tuesday June 07 2022, @02:11AM (1 child)
unless the active volcano erupts and puts gigatons of now potentially radioactive ash into the air.
Better spot might be to drop it all in a mid ocean subduction zone, where one tectonic plates is going under the other, and then dropping enough rock on top of it to completely bury it. Given enough time all the waste material would end up under the other plate and not be an issue anymore. The water would keep it cool and the pressure would keep the water from boiling off.
An even better option for at least the fission byproducts most people worry about would be to put those into a properly designed reactor and use neutron exposure to convert them into inert elements or isotopes with much shorter and manageable half-lives
"Beware those who would deny you Knowledge, For in their hearts they dream themselves your Master."
(Score: 2) by PiMuNu on Tuesday June 07 2022, @10:30AM
> mid ocean subduction zone
Might be tricky to construct stuff under ~ 5 km of water.
(Score: 2) by Rich on Tuesday June 07 2022, @01:18PM (1 child)
Does anyone know what kind of waste naval reactors end up with after their tour of duty? These run high-enriched fuel and burn up much of that over many years, so a lot of transmutation must be going on. (As opposed to commercial reactors which just burn a bit over 1% of the fuel and mostly end up with fission products and a bit of other irradiated stuff).
(Score: 0) by Anonymous Coward on Tuesday June 07 2022, @04:20PM
The navy wants to have some reserve range when their ships are brought in for refuelling so there is no risk of running out if the refuel is delayed due to war or other emergency while commercial power plants want to hold off on refuelling for as long as possible to reduce costs, maximizing burn.
Even the crappy light water reactors used in the US burn ~3% of their fuel. Modern designs are around twice that.