Thorium-Based Nuclear Power

[Northstar1989]

This is a thread intended to promote discussion of the advantages and disadvantages of Thorium-based nuclear power, primarily in comparison to Uranium-based nuclear power, but also compared to other energy sources.

Some required reading (read at least one article, or you'll have no idea what this is about)

http://en.wikipedia.org/wiki/Thorium-based_nuclear_power

http://www.world-nuclear.org/info/current-and-future-generation/thorium/

http://www.csmonitor.com/Environment/Energy-Voices/2014/0328/Thorium-a-safer-nuclear-power

http://www.csmonitor.com/Environment/Energy-Voices/2014/0328/Thorium-a-safer-nuclear-power

http://in.reuters.com/article/2013/12/20/us-breakout-thorium-global-idINBRE9BJ0RR20131220

Regards,

Northstar

[phoenix_ca]

CANDU reactors can already use it as a fuel. They can also use natural uranium as a fuel. And plutonium. And LEU. And...well this image shows it more clearly:

It's amazing what using heavy water can do for a fission reactor (to say nothing of being able to refuel the reactor as it's running, so no need to turn it off until it reaches the end of its life cycle...in theory at least, this is definitely not the case in practice but the simplified refuelling process helps). So hey, Canada's totally ready to use thorium whenever the need arises. The only big issue with these things is the relatively high cost of the heavy water, but it still results in pretty darn cheap energy. And once you have one running, you can basically stick any somewhat fissile material in the thing and as long as you're smart about it it'll burn it.

They also cannot be used to breed weapons-grade plutonium. Sooooo...I'd say we've got these issues covered over here.

Question: Do you mean to specifically talk about molten-salt reactors? Because if so then yes, in terms of cost (if the darn things can be made to work on a large scale soon; honestly the prospects for DPF and polywell fusion look somewhat better at this point), they could certainly out-shine most uranium reactor designs.

Edited May 31, 2014 by phoenix_ca

[Nuke]

all i can say is go canada. please invade us.

[bsalis]

CANDU reactors a pretty awesome (though they have a slight positive void coefficient). However they are still a PWR.

The real safety benefit of Thorium is the molten-salt reactor design. From what I understand they still need some R&D, but they should be viable. You can also build them to be small or large as needed.

[phoenix_ca]

The real safety benefit of Thorium is the molten-salt reactor design. From what I understand they still need some R&D, but they should be viable. You can also build them to be small or large as needed.

China hopes to have one in ten years, but as one of the articles from the OP remarks, this is something of a pipe-dream. Estimates are usually around the 25-year mark for getting a practical thorium molten-salt reactor built.

[Kryten]

They also cannot be used to breed weapons-grade plutonium. Sooooo...I'd say we've got these issues covered over here.

²³³U is fully usable as weapons material, and they produce plenty of that.

The real safety benefit of Thorium is the molten-salt reactor design.

MSR does not require a thorium fuel cycle, most have used low-enriched ²³⁵U.

[phoenix_ca]

²³³U is fully usable as weapons material, and they produce plenty of that.

Sure it does...if it's using thorium for fuel. U-233 is produced from Th-232 (U-233 production is actually a well-known part of the thorium fuel cycle). The reasons for CANDU reactors being relatively harmless when it comes to proliferation isn't because they don't produce nasty stuff like plutonium, it's that they're terrible at it (that Pu can be burned anyway, not that you'd want to try to get it out of the spent fuel, given reprocessing costs). There are far better reactor designs if your goal is to actually extract weapons-grade plutonium from it.

Besides, there are other problems with using U-233 for weapons, namely that it contains some U-232, which is really nasty in terms of gamma ray emissions when compared to Pu-241. Like "you need a hell of a lot more shielding and you can forget about handling your nuclear weapons with any ease" sort of nasty. U-233 was studied for use in nuclear weapons and at least part of the reason it isn't is because it's so liable to kill the people working with it. It poses a relatively low proliferation risk compared to natural or enriched uranium fuel, which is good news for reactors based on using thorium for fuel.

Relevant reading:

https://www.princeton.edu/sgs/publications/sgs/pdf/9_1kang.pdf

http://hal.archives-ouvertes.fr/docs/00/10/31/27/PDF/C111.pdf

Edited May 31, 2014 by phoenix_ca

[Northstar1989]

MSR does not require a thorium fuel cycle, most have used low-enriched ²³⁵U.

MSR can *technically* be done with Uranium, but Thorium is VASTLY superior for MSR due to its much higher melting-point (it's right in the articles I listed in the OP). I think that's what he meant by the real benefit of Thorium being MSR designs...

Regards,

Northstar

[Northstar1989]

China hopes to have one in ten years, but as one of the articles from the OP remarks, this is something of a pipe-dream. Estimates are usually around the 25-year mark for getting a practical thorium molten-salt reactor built.

I don't know where you get the 25-year figure. The only country making a truly serious effort to develop Thorium reactors is China (other countries are researching it, but at much lower budget and labor levels). Their original estimate was that it would take 25 years, but then the government stepped in and massively increased funding and asked that it be completed in 10 years. And ambitious goal, but with enough money, by no means impossible. There are few problems you can't solve by throwing enough money at them...

Forgive me if this sounds ignorant, but the Soviets already had a working molten-sodium cooled reactor design (TOPAZ-II) developed for use IN SPACE by 1991 at the very latest (this is when they first presented the design to the US, with an interest in selling it. God only know when they actually completed the design with Russian secrecy...) Isn't that essentially the same thing as a Molten Salt Reactor, or is there a distinction between the designs I'm missing?

Also of interest, they launched two TOPAZ-I reactors to LEO in the late 1980's (aboard COSMOS 1818 and 1867), each capable of generating 5 kW of power for 5 years off 12 kg of reactor fuel... That doesn't sound very impressive to most KSP players since solar panels are DRASTICALLY overpowered for their size/mass in this game (assuming 1 EC = 1 kW), but that's actually a MUCH better power density than solar panels of the time (and later designs would have been even better).

Regards,

Northstar

Edited May 31, 2014 by Northstar1989

[Kryten]

I don't know where you get the 25-year figure. The only country making a truly serious effort to develop Thorium reactors is China (other countries are researching it, but at much lower budget and labor levels).

India's program is far ahead of China's; they see it as their only real chance for energy independence. All new reactors are partially fueled with thorium, they're producing large-scale breeder reactors, and they've even tested a ²³³U bomb.

[Nuke]

using liquid metal coolant is different from a molten salt reactor. msrs usually have the nuclear fuel dissolved in the salt, so the salt is the fuel. the russian topaz reactor was still a solid core reactor, i believe it was cooled with NaK alloy, but this is only a heat transfer medium.

the aircraft reactor experiment back in 1954 had one of the first molten salt reactors ever built, the reactor was ran for 9 days. this was followed by the molten salt reactor experiment in 1965. the resulting 7.4MW reactor ran for a year and a half at full power. i think msrs were pretty much shelved in favor of research into fast breeders back in the 70s. blame nixon, its all his fault.

[phoenix_ca]

I don't know where you get the 25-year figure.

Then you need to read the articles you posted in the OP. I recall seeing that estimate elsewhere too (though I'm having trouble remembering where), which is why I mentioned it.

Edited June 1, 2014 by phoenix_ca

[Northstar1989]

Then you need to read the articles you posted in the OP. I recall seeing that estimate elsewhere too (though I'm having trouble remembering where), which is why I mentioned it.

One of the articles lists that for the original timeline that China planned to develop Thorium power on before they decided to accelerate it to 10 years. I think *that* is what you're getting mixed up with estimates being that it WILL take 25 years...

Regards,

Northstar

[phoenix_ca]

One of the articles lists that for the original timeline that China planned to develop Thorium power on before they decided to accelerate it to 10 years. I think *that* is what you're getting mixed up with estimates being that it WILL take 25 years...

It's possible. I'll grant you that it'll take 10 years, though that's still a lot of money and a lot of time later.

[Idobox]

It's possible. I'll grant you that it'll take 10 years, though that's still a lot of money and a lot of time later.

10 years is very short for nuclear industry.

Building a nuclear power plant using an old design takes 3 to 5 years, sometimes more. Taking 10 years to build a functioning reactor of a new type (not just a new model) is very quick.

It is a bit worrying in terms of sfety.

The biggest issue with MSRs is that you need pipes that can withstand super hot corrosive molten-salt and constant low-intensity irradiation, and it takes time to see how different material age in these conditions (you want them to last decades). I wouldn't like to work in one of the first generation power plants if they follow that schedule, I'd be afraid of leaks.

The other issue is separating protactinium from the fuel to let it decay to Uranium. It is not as difficult as enriching uranium, but the stuff is radioactive, and you want to extract it from radioactive molten fluoride salts at a high rate, which pose an interesting design challenge. The reactor can work without extracting the Pa, but it will be considerably less efficient and produce much more transuranid waste, making it no better than Uranium cycle.

[comicbstudeo]

didnt we already have MSRs back when they were deciding to use thorium or urainium

[Northstar1989]

CANDU reactors can already use it as a fuel. They can also use natural uranium as a fuel. And plutonium. And LEU. And...well this image shows it more clearly:

http://upload.wikimedia.org/wikipedia/commons/f/fe/CANDU_fuel_cycles.jpg

It's amazing what using heavy water can do for a fission reactor (to say nothing of being able to refuel the reactor as it's running, so no need to turn it off until it reaches the end of its life cycle...in theory at least, this is definitely not the case in practice but the simplified refuelling process helps). So hey, Canada's totally ready to use thorium whenever the need arises. The only big issue with these things is the relatively high cost of the heavy water, but it still results in pretty darn cheap energy. And once you have one running, you can basically stick any somewhat fissile material in the thing and as long as you're smart about it it'll burn it.

They also cannot be used to breed weapons-grade plutonium. Sooooo...I'd say we've got these issues covered over here.

Question: Do you mean to specifically talk about molten-salt reactors? Because if so then yes, in terms of cost (if the darn things can be made to work on a large scale soon; honestly the prospects for DPF and polywell fusion look somewhat better at this point), they could certainly out-shine most uranium reactor designs.

Didn't respond to this before- but CANDU reactors look pretty awesome. Very impressive- I'm surprised we aren't building more of them...

I'm also always curious to talk about other reactor designs- not just MSR's...

Regards,

Northstar

[Northstar1989]

10 years is very short for nuclear industry.

Building a nuclear power plant using an old design takes 3 to 5 years, sometimes more. Taking 10 years to build a functioning reactor of a new type (not just a new model) is very quick.

It is a bit worrying in terms of sfety.

The biggest issue with MSRs is that you need pipes that can withstand super hot corrosive molten-salt and constant low-intensity irradiation, and it takes time to see how different material age in these conditions (you want them to last decades). I wouldn't like to work in one of the first generation power plants if they follow that schedule, I'd be afraid of leaks.

The other issue is separating protactinium from the fuel to let it decay to Uranium. It is not as difficult as enriching uranium, but the stuff is radioactive, and you want to extract it from radioactive molten fluoride salts at a high rate, which pose an interesting design challenge. The reactor can work without extracting the Pa, but it will be considerably less efficient and produce much more transuranid waste, making it no better than Uranium cycle.

The piping issue is I think the main thing they're struggling with right now, from what I read on China's efforts on MSR's (the main design for Thorium-based reactors they are focusing on).

But, I wouldn't put it beyond them to have a functional reactor in 10 years- after all, this is China, the country that sold the USA tea leaves dried by idling trucks with leaded gasoline over the crates, thus giving us tea heavily contaminated with lead; and watered-down milk cut with highly toxic chemicals to hide its lowered protein content (due to the watering-down) in tests... Who said anything about safety?

Regards,

Northstar

P.S. Those were both real incidents I learned about in my Biosecurity class my first tear of grad school... Fortunately the contamination was in both cases detected by random inspections of shipments (which only occur on about 1-10% of incoming cargo, depending on what it is and the available manpower) by customs officials at the seaport. Who know what other stuff *didn't* get caught by random inspections though...

Edited June 3, 2014 by Northstar1989

[phoenix_ca]

Didn't respond to this before- but CANDU reactors look pretty awesome. Very impressive- I'm surprised we aren't building more of them...

The main issue is capital cost. Filling the calandria of a CANDU and its cooling systems with heavy water costs a lot of money. Hopefully the ACR-1000 design, which has a smaller calandria and uses light water in its cooling loops, will lessen that cost somewhat. If you strictly want to get the cheapest power possible, then pressurized LWR designs have their benefits. CANDU was developed here partly as an option to use nuclear power without an enrichment infrastructure. We had lots of uranium but no enrichment facilities, mostly because we weren't interested in making nuclear weapons (having a friendly nuclear power next door kinda makes it a moot point). At the very least one can probably re-use some or all of the heavy water that is left after a reactor reaches the end of its life cycle, unless I'm mistaken. It's easy to find information about how CANDU reactors can reuse fuel; not much on how or even if new reactors can use the water from older ones. I might have to actually contact the government directly. O.o

CANDU designs are likely to stay for a while though, and Canada sticks by it (for rather obvious reasons), so they can serve as the "garborator" of the nuclear industry, so-to-speak, burning "waste" fuels that are left-overs from other reactors with minimal reprocessing. Which in terms of fuel costs, is a very good thing in the long run for Canada.

Edited June 3, 2014 by phoenix_ca

[cantab]

My thoughts:

Could thorium be a useful nuclear fuel? Sure. Is thorium a magic bullet that will make all the problems with nuclear fission go away? No.

[Northstar1989]

The main issue is capital cost. Filling the calandria of a CANDU and its cooling systems with heavy water costs a lot of money. Hopefully the ACR-1000 design, which has a smaller calandria and uses light water in its cooling loops, will lessen that cost somewhat. If you strictly want to get the cheapest power possible, then pressurized LWR designs have their benefits. CANDU was developed here partly as an option to use nuclear power without an enrichment infrastructure. We had lots of uranium but no enrichment facilities, mostly because we weren't interested in making nuclear weapons (having a friendly nuclear power next door kinda makes it a moot point).

Nuclear proliferation is a stupid idea anyways. In Thermonuclear War, nobody wins. "The only way to win is not to play", to take a quote from WarGames...

At the very least one can probably re-use some or all of the heavy water that is left after a reactor reaches the end of its life cycle, unless I'm mistaken. It's easy to find information about how CANDU reactors can reuse fuel; not much on how or even if new reactors can use the water from older ones. I might have to actually contact the government directly. O.o

Try asking that of the United States government, and you might end up on the terrorist watch-list. Oh Canada, how I love your lighthearted innocence...

CANDU designs are likely to stay for a while though, and Canada sticks by it (for rather obvious reasons), so they can serve as the "garborator" of the nuclear industry, so-to-speak, burning "waste" fuels that are left-overs from other reactors with minimal reprocessing. Which in terms of fuel costs, is a very good thing in the long run for Canada.

Which in terms of minimizing long-lived radioactive waste, is a good thing for EVERYBODY. In fact, after reading up on it, IMHO it would be best if EVERYONE switched over to CANDU reactors or other designs with that kind of fuel-flexibility, and abandoned other waste-heavy reactor designs entirely...

Regards,

Northstar

[phoenix_ca]

Nuclear proliferation is a stupid idea anyways. In Thermonuclear War, nobody wins. "The only way to win is not to play", to take a quote from WarGames...

Part of the problem there is that now that some of us have nuclear weapons, it's really, really hard to get rid of them. No one in that position wants to take their hands off the trigger first, so-to-speak.

Try asking that of the United States government, and you might end up on the terrorist watch-list. Oh Canada, how I love your lighthearted innocence...

Well AECL has a nice contact form on their website so I contacted them directly. Perhaps I'll have an answer to what happens to all that heavy water soon.

Which in terms of minimizing long-lived radioactive waste, is a good thing for EVERYBODY. In fact, after reading up on it, IMHO it would be best if EVERYONE switched over to CANDU reactors or other designs with that kind of fuel-flexibility, and abandoned other waste-heavy reactor designs entirely...

Unfortunately, even here, we have complete and absolute morons, campaigning against that which they don't understand. Thankfully, our government has thus far had the intelligence to not listen to their insanity. Here's a fun quote from their website:

"Its use of natural uranium and online fueling makes it attractive to countries hoping to acquire the capacity to divert plutonium from used fuel to build atomic weapons. India used a Canadian reactor to build an atomic bomb; AECL stated last week it would like to sell additional reactors to India."

Yeah no. The only part of that that might be true is AECL wanting to sell more reactors to India. The rest is just lies.

[Idobox]

I'm pretty sure a CANDU reactor run with uranium would produce some plutonium that could be used for weapons, without using these pesky centrifuges.

[phoenix_ca]

I'm pretty sure a CANDU reactor run with uranium would produce some plutonium that could be used for weapons, without using these pesky centrifuges.

It does, but the concentration is about half as much as an LWR.

Every fission reactor poses some proliferation risk, some more than others. If you want to make nuclear weapons, CANDU isn't a very bright choice. There are research reactors that would be better.

Edited June 5, 2014 by phoenix_ca

[Idobox]

It does, but the concentration is about half as much as an LWR.

Every fission reactor poses some proliferation risk, some more than others. If you want to make nuclear weapons, CANDU isn't a very bright choice. There are research reactors that would be better.

A nuclear pile is easier to design, but foreign governments are usually reluctant to sell you nuclear grade graphite if you plan to build a replica of Windscale, so you have to develop it yourself.

A CANDU can be bought under pretense of a civilian program, especially because it is so bad at producing plutonium.

Of course, if you don't feel up to the task of designing your own graphite moderator, then maybe you are not ready to develop nuclear weapons.