Can this reactor design burn thorium fuel too?
We have thousands of years of thorium available.
A company spun off from MIT is claiming it has cracked the holy grail of nuclear technology: a reactor design that runs on materials the industry currently discards as waste and which could meet all of the world's power demands for the next 70 years. It's also "walk-away safe," the designers claim, making it immune to the kind …
Can this reactor design burn thorium fuel too?
We have thousands of years of thorium available.
I'm sure by the time we've burned our way through the current waste stockpile, we'll have developed better alternatives, including thorium burners. I'd like to see this line of research given a massive boost, as this is certainly our best source of power so far.
I'm curious though... does the total amount of waste take into consideration any contaminated materials as well, or just the used fuel? And how do we get at the existing stuff that's buried in various sealed sites? I'm guessing this is more for fresh and un-buried stuff.
Still, hats off to the brains behind it all!
Sure, it'll burn. Most Thorium, not 100% but really close, is 232Th and it can be bred, by absorbing neutrons, to 233U which can then be used in a reactor. Bonus, as 233U undergoes fission it emits neutrons which can be fed into the 234Th to create more fuel for the reactor. Better bonus, this works great in liquid fuel reactors like the one described.
If it really works like they say and at the cost given, all I can say is holy shit Batman, that's a long ball. Hell, even if it's a pretty good stride toward pulling it off it's still a long ball home run.
Nice work, cheers!
How about on a cup of Russian tea?
We have millions of years of thorium available. The common fallacy is to count only proven reserves, but these reserves are based on current, much depressed prices, as thorium is next to worthless. However, a 1GW plant, using a sigle ton of thorium per year could tolerate almost any price of fuel. This rises reserves of thorium to billions of tons.
I can't see why thorium can't be added to the waste, the layout's similar to a thorium molten salt reactor except that it misses out the intermediate heat exchanger, probably for simplicity. http://en.wikipedia.org/wiki/File:Molten_Salt_Reactor.svg has a chemical processing plant in the fuel loop too although you could probably just adjust the mix and store the reprocessed waste like we do now.
"has a chemical processing plant in the fuel loop too although you could probably just adjust the mix and store the reprocessed waste like we do now."
Not so. The loop is to extract certain poisons from the salt which kill the reaction. Before its development you needed 2 layers of different salt mix which had to remain remain separate. The chem plant makes it run with 1 mix. It was a breakthrough in making the molten salt reactor concept viable.
No, you need the chemical plant to remove the poisons even if the plant IS run without fuel breeding, or if you run separate fuel/breeder loops.
It should be obvious, really - if you're going to breed 233U from 232Th, it has to involve a neutron absorbtion, then a decay period (the actual process transmutes 232 Th to 233Pa by neutron capture, which then undergoes beta decay to become 233U). The necessary neutron flux is only available in the core, where active fission is going on. Therefore, you're pumping the breeder salt through the core, therefore it's absorbing neutrons, and if you allow the Pa burden to become too high, it closes the reaction down - and you need it to undergo two more captures to become useful fuel, ie 235U). It doesn't matter if it's mixed in with the fuel salt, or a separate circuit, its still absorbing neutrons.
MSRs also depend on active and continual removal of fission products from the fuel loop. Some of that's easy (letting Xe and I come out of solution) and some's hard (CS, Sr and similar via tricks like vacuum distillation, which is a sod, and would be a horror to maintain in a highly active environment). And if there's any production at all of higher transuranics (which there would be in there were any 238U in the fuel salt - and that's inevitably until and if you get to a completely closed 233U based cycle), there's no removal mechanism at all, short of pyrolitics or something like purex.
The elephant in the room on this one is that very little if any nuclear waste is buried in a sealed site. Most of it is still sitting on the reactor site where it was created and put into "temporary" storage. Particularly here in the US where we've been waiting since the 1950s for that salt site in Nevada to open only to discover it now won't happen.
I was also thinking along the lines of: if it becomes a large-scale reality and old reactors shut down, where does it get it's fuel from? So I guess option 1 is that it can directly run on previously-unused Uranium, or else Thorium.
But never mind, doesn't really matter because many of these plants can run for 50+ years, by the time they've burnt all the current waste we'll have new technology to use Thorium.
Or fusion. We're getting that within 50 years, right?
"If it really works like they say and at the cost given"
Never mind that, even if it works half as well as they say and costs twice as much it would be a humungous leap forward
El Reg's metals wide boy here. Thorium is not next to worthless. It has a negative value.
The costs of getting rid of some (radioactive waste storage, licenses etc) plus the fact that almost no one at all uses it for anything means that possession of thorium actually costs you money.
A decade or so ago I procured a 13 lb piece for a customer. The actual metal was given to me free. It then cost $27k for the licenses and transport (including 18 wheeler, police escort, the whole schlemiel) to get it to the punter. According to the industry data that was the only commercial transaction for thorium in the US that year.
Another comment on the same point. If you have a mineral with high Th content (say, tantalite, that's a possible one, or monazite for rare earths) then you can't just process the Th out and flog it onto someone. Because no one uses it. You've got to build the costs of storing radioactives into your plan. And at higher levels (say, 1% Th or so but that's just a guess) the costs of that make the original mineral worth a negative number. And there are mountains of all sorts of things out there that won't be mined because of a high Th content.
Strangely, an actual commercial use for thorium probably wouldn't require anyone to go mining for Th. It would just enable us all to tap deposits of other minerals with high Th content. Now that we've got (or are going to get) a place where we can send the Th then lots of deposits of Ta, Nb, REs and so on would become viable.
Right at the moment I've some samples of euxenite and fergusonite (Ta and Nb bearing) in a lab for testing. The question isn't "What's the Ta or Nb values?". It's "Is the Th so high that we just shouldn't bother mining these extensive and wonderfully cheap deposits in a low wage and poor country?"
"If it really works like they say and at the cost given"
One thing about the cost, many current nuclear sites / nations are willing to pay lots of money to dispose of their nuclear waste*. So the operators of such a plant could get paid to burn the waste, even if it's just a small amount that only covers operational costs of the plant.
A 500 MWe plant operating for say 30 years, that's 262980 hours (call it 200k to account for downtime / maintenence). That's a lifetime supply of 100 million MWh. Even if the plant costs double the estimate (so, $3bn), the plant will be producing electricity at $30/MWh, or less than half even the cheapest of current cheap sources: http://en.wikipedia.org/wiki/Cost_of_electricity_by_source
Of course if there are many of these plants built and they have to compete between them for fuel, governments would no longer pay to get the current waste removed, but they could still probably at the least get the fuel for free. Sure, there are other cost factors involved, but essentially even if this plant costs 2-4 times what the designers claim, it will still be competitive with current fossil fuels.
*at least, I keep seeing estimates saying how many billions it would cost to get rid of the waste
You're missing O&M (fairly minor), fuel (very small), and "cost of capital" (big) in that. would it were that simple....
"You're missing O&M (fairly minor), fuel (very small), and "cost of capital" (big) in that. would it were that simple...."
And I challenge James Micallef on building a 500 MW plant for even $3bn......
Realistically it's going to be no cheaper than a current generation reactor, and then suffer the same cost over-runs as all new technologies. In the nuclear sector the cost over-run for novel technologies is 300%.
So that makes the starting price when fully designed would be around $5bn minimum, and then the obligatory over-runs would take that first plant to $15bn. That might still develop new, workable technology that can be built subsequently at lower cost, but the electricity isn't going to be cheap from that first one.
And could I just say Andydaws, thank you for your excellent, excellent contributions!
"And I challenge James Micallef on building a 500 MW plant for even $3bn......"
Actually, that's not far out of line with current costs....Votgle (the first gen III+ project in the US) is about $6bn/GW.
"Actually, that's not far out of line with current costs....Votgle (the first gen III+ project in the US) is about $6bn/GW."
Well, there's a very obvious reason that the costs are close, because I used the Votgle estimates as a fair benchmark!
Worth noting that first reactor commissioning has already Votgle is already a year late for first reactor online, so the chances of completing on budget are negligible unless they've built in the fattest of fat contingencies.
Well then - why not build the new molten salt reactors on these same sites?
The sites are already there, and have experienced staff nearby, plus the waste does not have to be transported over a long distance. Existing sites will also have the high voltage generator sets and transmission transformers/wires too.
There aren't any "sealed sites".
The world's first geological repository is under construction in Sweden, but that's some years away from completion. Pretty much all the waste produced to date remains "above ground". In the UK, France and a few other places, a proportion of the waste is at reprocessing sites (Cap de la Hague in France, Sellafield UK). Even in those cases, only a minority of the waste has been reprocessed, and the fission products/non-fuel actinides separated out.
Outside that, almost all fuel remains at the reactor sites, in cooling ponds (in a couple of cases, it's in air cooled storage facilities - the largest is at the Wylfa magnox plant). In the Us, a lot of fuel has been moved out of ponds into air-cooled storage flasks, also held at individual reactor sites - since the US has failed to move ahead with a repository.
In that latter case, if they'd any sense, they'd simply move those flasks to somewhere like New Mexico, on a seismically stable site with dry weather,
let's get fracking, and I can make a killing on gas mantles!
"Well then - why not build the new molten salt reactors on these same sites?"
Please accept my "Great Ideas That Have Already Been Implemented" Award.
Virtually all recent nuclear projects (Oykluoto, Fallamanville, Vogtle) and all the proposed UK sites are indeed adjacent to existing or former power generation reactors. Doesn't help much with the costs. The experienced staff are already busy (and usually old), and the transmission connectors are the least of your cost worries.
The major gain in doing this is that common security can be implemented (a convenience rather than a cost saver), and the local population are usually very receptive to new nuclear reactors, reducing the planning difficulties by a few years.
Safe nuclear: India’s thorium reactor
Can this reactor design burn thorium fuel too?
It doesn't sound too dissimilar to other Thorium-based molten salt reactors I've read about (including the fail-safe "plug" that melts and has the salts draining away into several sub-critically sized reservoirs), so I'm guessing yes. As I understand it, though, the fuel cycle for Thorium would have to include elements outside the actual reactor, for chemical separation of various waste (or "poison") isotopes that would get in the way of a self-sustaining reaction, and possibly other similar steps (for maintaining other ratios of elements). Someone here once pointed out that the chemical separation process is pretty nasty (dangerous) based on the need to use (iirc) fluorine. Apart from that, in a Thorium reactor, the main "fuel" is actually Uranium, which is a decay product of Thorium, so there shouldn't be that much difference in the reactor design.
@Ledswinger - hehe you're joking right? <rummages around in pockets> what can I get for 20 quid? :)
Seriously, I got the $3bn from doubling the estimate of the project designers. I have no idea how accurate or possible that is, but I think a factor of 2 on their estimate is reasonable. If it is, as you say, 3 times as much that's still not be too expensive, based on back-of-fag-packet rough calcs, always assuming that governments running old-generation reactors are willing to pay the costs to get rid of their spent fuel and thus provide these new reactors with free fuel.
@andydaws - cost of capital on $3bn would be quite large but I'm willing to bet that China / India etc would happily underwrite most of that if it meant solving their energy problems. Also (for the moment at least), credit is dirt cheap
"@Ledswinger - hehe you're joking right? <rummages around in pockets> what can I get for 20 quid? :Seriously, I got the $3bn from doubling the estimate of the project designers."
OK, you really reckon that you can get a 500 MW nuclear plant for $3bn or $1.5bn? Using totally unproven technology? I'd love to believe this was credible, but there's no evidence that it would be. At $1.5bn per 500 MW, the cost estimates are in CCGT territory. Maybe they are right, but we've had thirty years getting CCGT right, and there's no complex certifications, no complex fuel needs, no huge security needs, and we understand the underlying physics and chemistry very well indeed. If it goes catastrophically wrong you kill about fifteen engineers and technicians, with no harm to anybody else.
A CCGT takes gas, burns it in a turbine that spins a generator, and recovers power from superheated waste gas. Easy peasy. Do you really contend that these unproven nuclear technologies are comparable in their risk, complexity and cost?
The storage facility in Nevada was never used, because the lunatics wouldn't allow the waste to be transported.
I can't resist adding that in a previous job, after I had persuaded the "industrial chemist" to pursue alternative career opportunities, I found he had squirreled away a cupboard full of exotica. Including a kilo jar of thorium oxide. These had all been bought in the days before you had to fill in forms about this kind of stuff.
It "only" cost £4000 to get rid of it, making it worth even less than Tim's - i.e. -$6500 a kilo rather than -$5000.
"Do you really contend that these unproven nuclear technologies are comparable in their risk, complexity and cost?"
I wasn't contending anything.... maybe I should make it more clear, I have no idea what a 'traditional' nuclear power station costs to build, nor indeed a CCGT station etc. I was merely looking at the claimed cost of the designer, assume that they are being optimistic (because hey, it's their baby), and doubled their estimate.
If, as you say, their estimate is the same as CCGT plant, then it's indeed a bold (and probably off by a significant factor) claim.
Doing nuclear for double that ($3bn) is definitely overly optimistic for an initial build, but maybe can be approached if there are dozens of them being built every year for many years. More than the complex certifications, security etc, I think you hit the nail on the head with "we've had thirty years getting CCGT right".
When we are building dozens of CCGT plants, every time the builders are giving feedback to the designers to improve the design and lower the cost, as well as learning tricks and shortcuts that will reduce cost while still delivering the end result.
With nukes, there is no reason this process couldn't also happen IF we were building dozens of nuclear plants every year for many years, eventually the cost would drop significantly from the first build. BUT I doubt that this will happen, in the west at least, there is still too much unwarranted fear.
I really, really, really hope this is real. And I really, really, really hope that if it is real, it happens.
Unfortunately, I suspect that the general population (and a good chunk of the non-general population, for that matter) will see 'nuclear', think 'fukushimachernobylmushroomcloudwasteexplodeohmygodcancer' and run screaming from our only real hope of freedom from fossil fuel.
We need a government organised, determined, and, if you like, ruthless enough to push this through regardless of such concerns.
No, they'll think China Syndrome because they can't actually remember all those other things.
You see, for a moment there I was - well happy - hopefull - optimistic even.
But you had to go and ruin it didn't you.
Maybe with all these reactors going to China they'll start calling it the "US Syndrome".
Rather than 'fukushimachernobylmushroomcloudwasteexplodeohmygodcancer', it should be rpesented to the public as 'disposalofhighlyradioactivewastethatnobodywantsanywherenearhtembecuaseoffukushimachernobylmushroomcloudwasteexplodeohmygodcancer'
More of a mouthful, admittedly...
How about in German..? They like to lash word together with gay abandon:
The delays to the current increase in nukes (regardless of their type) is almost nothing to do with safety, it's the companies willing to invest in building them negotiating (demanding) a higher market energy price.
Unfortunately, since there's only one company left at the table, the conversation is mostly one-sided as we know we need a future energy supply and have almost no either viable options.
I'm thinking more on the lines of "deja vu", "breeder reactors", "Superphenix" and "funny liquid sodium leaks".
It made me quite wary of overenthusiastics promises...
That someone at some point explains to the general populace what "Radioactive for thousands of years" means.
Because something that is radioactive for so long does emit a very low amount of energy, and it is not that dangerous as long as it is not dispersed.
The danger with radioactive stuff comes from short-lived and medium-lived isotopes.
Oh. When I was in Munich I saw that on signs everywhere, but I thought it just meant 'exit'.
"We need a government organised, determined, and, if you like, ruthless enough to push this through regardless of such concerns."
sadly the current UK government only has the third of those qualities ...
For maximum irony they should all run screaming to Cornwall, which has little industry, no nuclear plants, and is more radioactive than much of the exclusion zone around Fukushima.
I'm assuming there will need to be a full scale demonstration plant built, tested and certified. So it's years if not a decade or more away from commercial deployment. It's not going to be the thing that gets our government out of the hole it and its predecessors have dug, because long before its available we'll probably be having scheduled power cuts and a government telling us that it's good for us and that we're helping save the planet.
"we'll probably be having scheduled power cuts and a government telling us that it's good for us and that we're helping save the planet"
LONG POST, GET A COFFEE NOW
Very probably. From a UK perspective, this is what the near future holds for those responsible for UK energy policy:
1. Having given away sovereignty to the EU, and allowed the Eurocrats to invent the Large Combustion Plant Directive, allow one eighth of UK power generating plant to be forcibly retired by the end of 2015. That's 11.8 GW shutting down out of a total of 84 GW of reliable capacity, plus the separate closure of the Magnox plant at Wylfa, taking out another 1 GW. These retirements are already happening, and once retired there's not much chance of reinstatement - there's no commercial reason to mothball the plant, it is also very difficult to mothball coal fired plant, and there's a commercial imperative to dismantle the site and sell for redevelopment.
2. Commission a handful of new CCGT's in the next couple of years of around 6 GW (but with no central oversight of the commissioning dates, so real wing & prayer stuff). Hope that 6 GW minus 12.8 GW equals zero.
3. Introduce carbon floor tax. Look on in wonder as the marginal third of plant currently opted in for LCPD (ie coal plant that DECC think will keep running) exits the market because it isn't profitable to run. Subtract another 3 to 6 GW of capacity, and act surprised. Pray that peak demand of 60 GW continues to shrink. With a rising population, increased use of things like heat pumps, and sod all industry left to offshore, further falls in peak demand seem an act of faith, with any credible forecast indicating it ought to rise towards 62 GW.
4. Make warm, welcoming sounds about how all the many GW of renewables will fill the gap - ignoring that they will contribute nothing to peak demand because that's typically after dark on very cold, very still days. Continue to pour bill-payers money into renewables, despoiling the countryside for no benefit. Likewise, point to international interconnectors - again ignoring the fact that peak demand tends to be regional, and these can't be depended on at critical times. With Germany progressively closing down its nuclear fleet, Belgium and Switzerland likewise, the availability of surplus French nuclear power cannot be presumed, because those countries will become net importers. Historically Germany has been the swing producer of Europe, and exported power, so this is a big an unhelpful change.
5. Continue lacksadaisical UK approach to nuclear funding and approval. This is already on a knife edge, with nobody willing to commit to build unless the government agree that they will be paid double current wholesale prices. The two potential builders could both yet walk away from the table within weeks. Even so, the soonest new nuclear plants will be operational is a decade or more away. The actual construction is relatively quick - could be done in three years, but the design, procurement, legislative permissions and approvals and infrastructure enablement will treble that.
6. Realise that by January 2016 UK reserve margin will have fallen from around 20% to 8%, the lowest level in several decades - industry rules of thumb put minimum safe reserve capacity at 15%. This means that you're in trouble if more than three or four major power plants go offline at once. Convince yourself that this is fine. It isn't because you can expect two of the fifteen UK reactors to be offline even in the winter peak for statutory inspection, maintenance or repairs (you can't do the whole fleet all in the summer). So now if one or two conventional plants go down (or their transmission links fail), we're in big trouble.
7. Sometime between now and winter 2016/7 panic, and incentivise the building of new CCGT. These incentives will (as usual) be added to the peasants electricity bills. This creates a further problem, that UK generation will become yet more gas dependent, compounded by the circa 2019-2023 retirements of the older AGR nukes. Accelerated build of CCGT sounds good, because they're quick to build, but the bureacratic approvals still take years, the enabling infrastructure (eg high capacity gas lines) still takes years unless you've very lucky in location, and with procurement lead times it is still an absolute minimum of six years, often more like nine.
8. Lose next election, retire on fat, undeserved parliamentary pension, with equally undeserved "resettlement grant". Or in the case of DECC, retire early on gold plated and undeserved PCPS pension. Laugh at how you've made a comfortable and secure living from f***ing the country over.
If you've got this far, well done. There's a few minor simplifications in all of this, but as a broad brush this is all based on fact. Which is most unfortunate. If El Reg want to do some more digging to establish whether this is correct or not then I'd be willing to give some pointers to how to go about it.
>> Very probably. From a UK perspective, this is what the near future holds for those responsible for UK energy policy:
Brilliant, and what I've been trying to tell (without having all the numbers to hand) people for years. There is just one thing left out ..
At each stage of crisis, the treehuggers will wave their hands in the air dismissively, and point out that a) wind is reliable because it's always windy somewhere, and b) when we get smart meters, we'll **just** adjust our lecky usage to suit. Of course, anyone who actually has any idea how things actually works knows that both those arguments are male bovine manure.
The idiots in Westminster will just keep believing this idealogical rubbish, and keep repeating it in response to any criticism or suggestion of impending doom.
Meanwhile, anyone who cares about living a normal life is starting to look at putting their own small diesel genny in (if they are ina position to) - with heat recovery to make it (probably) cheaper than mains lecky for at least some of the time !
Written as one of those of us who remember the power cuts in the 70's, and how nuclear saved out bacon back then.
Or to put it another way, salt.
Although the idea of disolving stuff in molten salt is quite enthralling.
Yeah you could get rid of "radioactive" bodies...
"Although the idea of disolving stuff in molten salt is quite enthralling."
It's common in many industrial processes already e.g. aluminium production. Note that the article should say a salt not salt which many might take to be sodium chloride.
"Or to put it another way, salt."
This has been a regular part of MSR designs. To remain solid the plug has to be actively cooled.
So a power failure to the support systems (as happened at Fukushima) goes like this.
Reactor contents spread out in holding tank and go sub critical and await collection and remelting. Massive increase in surface area allows heat to be taken away through conduction and (thermal) radiation.
I think you slightly underestimate the heat removal issue - we're talking in the order of 10-20MW in the immediate aftermath of a fuel drain-down. Expecting to do that simply through convection into air would require a pretty immense large area, nless you assume either pumped flow, or two-phase of some sort - and that implies a secondary coolant supply (probably water)
In reality, it probably two-phase cooling to get the decay heat away - which puts you back in the same sort of place that you've got on the 72-hour passive cooling arrangements on an AP1000 or EU-BWR. That is, a tank above the decay heat source, allowing boiling off the walls of the fuel draw down tank, with water supply by gravity.
Oh, and by the way - that drain-down tank is going to be a pretty huge source of "gamma shine" - which means it'd have to be behind several meters of concrete, and but still have to have good air/water low. And it also means that any equipment associated with it would have to be entirely remote-operation, and maintenance. Once that tank had been used, you'd not be re-entering it's immediate area for a few decades, to fix anything - like the pumps required to move the fuel back into the reactor.
That you won't be going near the tank for decades is better than not going within 100km of the destroyed nuclear power plant for eons. The point is that the tank is there for a major catastrophic disaster. So it doesn't matter if it takes days or weeks to cool down or that you might never be able to get the contents out.