World’s First Thorium Reactor Designed | Hacker News Reader

World’s First Thorium Reactor Designed

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115 pointssasoon54 comments

Note that this very different to the molten salt LFTR design. With solid fuel it is very hard to prevent protactinium capturing neutrons, which means problems for breeding and waste and probably operational constraints as well. The LFTR is such a beautiful consistent design but it is very different from ordinary reactors.

Also the title is inaccurate as different thorium reactors have been designed, built and operated. See MSRE and THTR-300 for example.

I wish I had dug in further. I am substantially less excited now.

The big problem with a molten salt LFTR is the materials necessary for the plumbing. Any metal will become brittle as it is exposed to the radiation emitted from the reactor core. And manufacturing ceramics into the precision pieces called for is not a solved problem.

LFTR designs are fantastic, amazing, and solve a lot of problems. There is a lot of materials science to be done to make them viable, though.

You're confusing issues from pressurized reactors with LFTRs. The reason manufacturing ceramics for pressurized reactors is hard is the pressure and size involved. LFTR can be run at normal pressure at small scale; you can use a kiln as the pressure vessel if you want to.

Also, no, not any metal gets brittle; inconel and hastelloy handle radiation quite well for decades at a time, as does good old fashioned nickel. Beyond that, most reactor pressure vessels are a layer of metal then a layer of something that's really good at radiation, then the real pressure vessel, so that the interior layer's brittleness isn't very important.

We built and ran LFTRs commercially in the 1950s in New York State and Pennsylvania, before computers became a commercially realistic thing. They provided our grandparents no significant technical challenge.

The actual big problem with LFTR is primarily regulatory. The design hasn't been vetted to modern safety standards, which costs hundreds of millions of dollars, and the entities who are nuclear-aware and have that kind of money to throw around tend to be the existing nuclear companies, who can't switch to any other technology because they're deep in the Gilette Razor model, and anything that took out their existing fuel contracts would immediately bankrupt them.

There is /zero/ materials science needed to make a LFTR. I don't know where you got that idea. They're substantially easier than what we make today. The average auto body shop can pull it off.

>You're confusing issues from pressurized reactors with LFTRs.

Nope, pretty sure I'm not. I'm well aware that LFTRs run at low (even sub-atmosphere) pressures.

>We built and ran LFTRs commercially in the 1950s in New York State and Pennsylvania

We never ran LFTRs commercially. If you know otherwise, please cite. I only know of two experimental reactors at the Oak Ridge facility: the Aircraft Reactor Experiment and the Molten-Salt Reactor Experiment.

> I don't know where you got that idea.

I got that idea from some pretty simple facts about nickel alloys (like Hastelloy N) under neutron bombardment.

When you bombard nickel with neutrons, you produce helium. When the helium builds up irregularly, the alloy becomes brittle. You can dope Hastelloy N with titanium or niobium to even out the distribution of helium deposits (this is what ORNL did) but that brings the maximum temperature down to 650C.

As well, tellurium (one of the fission products of a LFTR reactor) corrodes the grain boundaries of Hastelloy N. You can reduce this effect by doping it with niobium and keeping the UF4/UF3 ratio to less than 60.

You have to trade off lower temperatures with whether or not you want to deal with beryllium toxicity. You can replace BeF2 with a eutectic lithium fluoride/thorium fluoride composition, but that requires an increased temperature of the reactor salts. There are other problems with using beryllium, though - it produces lithium-6, which is a strong neutron poison.

You also have to filter out noble element deposits, because they don't form fluorides.

There are also serious design challenges with modifying current turbines to work with supercritical CO2 or helium. You can use supercritical steam instead, but it isn't nearly as efficient.

You also have to worry about tritium diffusion. It's small enough that it leaks through the heat exchangers.

There are issues with the rapid expansion/contraction the graphite moderator, but some are working on graphite pebble designs.

Once you throw the corrosive salts, strange reaction byproducts, and neutron bombardment into the mix, I highly doubt that 'the average body shop' could pull off the fabrication of a LFTR style molten salt reactor that could run safely for longer than a week.

I was surprised to hear from GE that a CO2 working fluid power plant using turbine waste heat is a thing nowadays. They have a contractor, Echogen, who provides that part.

http://www.cospp.com/articles/print/volume-14/issue-01/featu...

http://www.echogen.com/documents/why-sco2-can-displace-steam...

In ships, when fuel costs just keep on rising, that starts making sense. (There are other reasons why it might not be good though.) On land power plants, it might make natural gas electricity more competitive against coal with this better efficiency.

Though I don't see the keyword supercritical on the Echogen site yet...

Oh neat, I didn't know about that either.

You are quoting verbatim as fact from an unsourced blog post you provide in another comment. That blog post says what you're claiming as fact are /rumors/. It points out beside the issue things like that a heat generation experiment that wasn't hooked up to dynamos didn't generate electricity, in literally the same paragraph as claiming they produced too much heat (so use some of it?)

In the meantime, it refers to hypotheticals as its only criticisms, many of which are mutually contradictory, many in ways as obvious as the above.

On top of that, one of the best bullshit detectors that has ever existed is watching for basic quality of language, and this guy has not yet mastered the wily apostrophe.

With apologies, I'm not going to be your unpaid research assistant tonight. You made a claim without evidence. I dismissed it without evidence. You seem to believe the burden of proof is now on me. Sorry; I have other things to do which are more important to me, and you flat out ignored several of the things I said, so I'm comfortable doing the same (like when you claimed that building ceramic housings was a challenge, and I thought you were confused about Japan Steelworks; you have provided no explanation for believing that ceramic containers, which Hitachi uses extensively, are out of our reach.)

Similarly, your story about grain boundaries is compelling, at least if you don't consider lining the reactor. But then you go on to observe that a 50s reactor ran for four years without a problem on 50s metallurgy, and don't seem to think that that's a problem for your concern.

Finally, that's true, you don't want to be around irradiated fluorine. But if you would rather be near a failed coal plant than a failed lftr, my interpretation is that you don't know much about what happens in either a fluorine leak or a coal plant explosion. Fluorinated uranium rain two countries away? Buddy, not even six blocks away. What makes that shit dangerous is how violently and universally it reacts. There would be less uranium and fluorine in the rain than in to day's seawater.

Helen Caldicott off, please. Either do the envelope math or stop pretending it's anything more than blog fuelled FUD.

> You made a claim without evidence

So did you :)

I wanted to add a couple additional points, separate from my other response:

Everything at Oak Ridge did _not_ provide our grandparents with insignificant technical challenges. Not only for the points (in my other response) about neutron bombardment making the Hastelloy N brittle, but also:

- The cooling circuit glowed red hot. This indicates that it was close to its thermal creep zone; we didn't know much about thermal creep back then. [0]

- The MSRE reactor spent a good portion of its life down for maintenance. [0]

- The tritium release is not a small problem: of an estimated 2.0TBq of tritium produced, 6-10% diffused from the fuel system into the containment cell atmosphere, and another 6-10% was released from the heat removal system. And these were lower than expected. You really don't want your LFTR to be leaking tritium everywhere. [1]

- The decontamination of the experiment was really, really hazardous. Not only were they dealing with nuclear waste; they were dealing with nuclear waste and fluorine gas. You really don't want to be anywhere near elemental fluorine gas. This was all because ORNL didn't defuel and store the salts correctly; it's mostly been rectified in modern designs[1]. But it goes to show how horrifyingly dangerous the components are. As bad as a nuclear spill would be, you have to remember that these aren't your run of the mill molten salts. They're highly toxic salts spewing out gamma, beta, and alpha radiation. I'm trying to imagine what it would be like if Chernobyl released these kinds of chemicals in its radiation plume. I don't think I can imagine something that horrifying. Toxic rain over Germany doped with uranium hexafluoride and plutonium? I'd rather have coal power. And I hate coal power.

Of course, all of this is me being extraordinarily cautious. I was really, really excited about LFTR design when I first heard about it. But the more I learn, the more I'm convinced that we really don't have the materials to safely operate one of these things on a commercial scale.

0. http://daryanenergyblog.wordpress.com/ca/part-8-msr-lftr/ 1. http://en.wikipedia.org/wiki/Molten-Salt_Reactor_Experiment#... (throughout)

The one mentioned in the article is Heavy Water Reactor with Thorium fuel. Here's its whitepaper: http://www.barc.gov.in/reactor/ahwr.pdf

The problem with nuclear power is not the primary fuel; it's the economics, especially the economics of big engineering:

http://www.carbontax.org/blogarchives/2013/11/21/why-officia...

http://www.forbes.com/sites/energysource/2014/02/20/why-the-...

Dealing with waste is also a major problem with most kinds of nuclear reactors. Safely dealing with spent fuel is expensive. For example, the largest meltdown in Fukushima was in a spent fuel storage pool.

Fast reactors and liquid thorium reactors would produce about one percent as much waste for the same amount of energy.

From the first link: "In those decades parts of plants were built, ripped out and rebuilt because of design and regulatory problems, leading to ruinous costs."

I've read about this before. Companies start building plants based on existing regulations. Along the way, the NRC changes the regulations, requiring tear-down and rebuilding. Meanwhile interest on the loan keeps building up. Add further delays due to political resistance and it's no wonder costs escalate.

It's not just the economics of big engineering causing the problem here. I think matters have improved somewhat in the U.S., but it's still going to be interesting to see how AP-1000 costs in the U.S. compare to those in China.

Incidentally, there are some arguments that liquid thorium reactors, and some other GenIV designs, could have significantly lower capital costs than conventional reactors. A big reason for that is that the basic physics of fuel and coolant provides substantial passive safety, rather than relying on lots of redundant active systems.

The interweaving of complex shifting regulations with the economics of $B plants that take decades to build and involve tremendous amounts of radiation and energy is not some random coincidence, nor is the absence of Buffets and Icahns lining up to make a killing on the erstwhile Future of Clean Energy (as opposed to wind and solar). If thorium can't solve the political economy problems, then thorium is dead. A small loud group of techies yelling "don't you get it?!" and upvoting thorium posts on HN is just part of the ??? between underpants and the profit we will never see.

As I implied above, it's a problem in particular jurisdictions, not necessarily everywhere. China for one is aggressively pro-nuclear. If thorium reactors are everything their advocates think they are, countries that throw too many obstacles in their path will disadvantage their economies.

Aside from that, nuclear reactors don't necessarily have to be gigawatt-size. Even in the U.S., smaller reactors are starting to make some regulatory headway.

But even conventional 1GW reactors don't have to take decades to build. China's first AP-1000s at Sanmen are being finished up this year and next for a construction time of five years.

http://en.wikipedia.org/wiki/Sanmen_Nuclear_Power_Plant

http://www.world-nuclear-news.org/NN-First-Haiyang-AP1000-ta...

China matters, and it can bypass procedural democracy. Large, slow-to-deploy nuclear still has to compete with quick-deploying, cost-decreasing solar and wind (and serious efficiency measures) while it is on the costs-rising-due-to-learning part of its rollout curve. Procedural democracy will not allow new nuclear of any kind in most of the rich democracies. We need everything, but solar PV, wind, and efficiency are the low-hanging fruit.

I agree we should pursue it all. Solar is rolling out pretty quickly right now. It's later, when we want to get past using fossil to compensate for intermittency, that nuclear will be especially important...and it would be good to be past that learning curve by then.

This is great news. I've read about so many great nuclear projects in the past few years. Three thorium initiatives in China, India and Norway. ITER in Europe. Bussard Electrostatic Fusion. Travelling Wave Reactors. General Fusion's Steam Hammer Design. And there are many more. So it looks like an increasingly bad bet to say that they will all fail. Which is good, because we're going to need lots of energy in the future.

I went to school next to THTR-300 which was built from 1971 on and is now defunct thanks to incompetence and huge failures in crisis management.

http://en.wikipedia.org/wiki/THTR-300

That, and incredibly unfortunate timing. I dare say that had the incident happened two weeks earlier, or several years later, there would have been no uproar - but for it to happen several days after Chernobyl, and for them to then try to cover it up... couldn't be worse.

Oak Ridge had a Thorium reactor in 1965. This is not the first.

The situation is actually even worse, here's a wikipedia link to a list of fifteen Th fueled reactors:

http://en.wikipedia.org/wiki/Thorium_fuel_cycle#List_of_thor...

I just went past one on the train to work. They're everywhere!

Oak ridge was a uranium MSR.

On what planet is this the world's first thorium reactor? We had running thorium reactors in the 1950s.

Fast breeder Thorium reactors and electric cars to the people! Cheap energy and clean cars.

I'm really glad to see that the concept is starting to take off.

It makes me sad that it's not happening in the US. If some folks in the government and business don't get their heads out of their asses a growth industry is going to bypass us entirely.

Note that you can breed U-233 from thorium and use that in nuclear weapons. The critical mass of U-233 is about 50% higher than Pu-239 but otherwise it's usable in implosion-type bomb designs; the main hazard is the presence of U-232 as a contaminant (which is a high level gamma emitter and makes it dangerous to work with) -- the real question is how they plan to reduce the U-232 contamination level enough to make weapons-safe U-233.

As India is already a nuclear weapons power, this has no immediate proliferation implications ... but moving a nation of a billion-plus people onto an energy cycle that produces weaponizable material as a by-product might be considered unwise by some. Cf. concerns in the 1970s and 1980s about the implications of running a "plutonium cycle" fast breeder energy ecosystem.

If everyone in the world had enough energy to live a developed-world middle-class lifestyle -- and with thorium reactors this might be feasible -- might that not eliminate one of the driving forces behind global conflict?

I'm not saying it's a slam-dunk win for sure.

But I have noticed a lot of general apathy and aversion to violence in the developed world largely because people are just too busy living their lives; they have a lot to lose.

> the real question is how they plan to reduce the U-232 contamination level enough to make weapons-safe U-233

I'm not convinced that anyone has this goal in mind. Maybe they just want to provide power to their countrymen and continue to lift India out of poverty. There might be nothing nefarious about this, unless you consider poor people getting less poor to be a problem.

In certain parts of the world, maybe. In other parts differences in religion is the driving force behind conflict..

It never really is. It's always about resources and power. Sure, there's often a holy book involved, but it's just a way to divide people into tribes, like nationality, color etc. It's always we want our (un)fair piece of the cake, where we is some group affiliation and it doesn't really matter what the affiliation is based on.

Disagree. Religion is the vehicle. Inequality is the driver.

There were/are religious conflicts in communities where it's impossible to tell the belligerents apart -- ethnically, economically, you name it.

"For every complex problem there is an answer that is clear, simple, and wrong."

Inequality is definitely a contributing factor, perhaps even _the_ contributing factor, but don't count out religion.

Inequality is the wrong diagnosis. As msandford pointed out, it's more likely to be a minimum standard of living issue and having enough to lose. If inequality was a main factor, you would expect Pakistan to have similar crime rates as Sweden, when in reality they're not even close. (PG has an essay on inequality being a boon to a nation's economy: http://www.paulgraham.com/inequality.html) You could also look at the religiosity of a country, but the trend there is that lower standards of living correlate with higher religiosity. (http://www.gallup.com/poll/142727/religiosity-highest-world-...) I'm more inclined to think the causation goes from low standard of living --> religiosity rather than the other way around, given the United States. However there could be other deeper factors that give rise to a low standard of living, such as a nation's average IQ -- you're not going to see a nation with average IQ of 70 outperform let alone match a nation with average IQ of 100 in terms of standard of living.

Good point regarding inequality vs absolute standard of living, but you're also talking about inequality within national boundaries. A good bit of the resentment of the Muslim world towards the West stems from perceived injustice and power imbalance on a regional or global scale.

There is also a big difference between inequality as a ratio of rich to poor, and actual conditions. The poor in Sweden are better off relative to the rich than the poor in Pakistan.

I don't understand the whole "it has to be capable of making bombs to be viable" thing.

I mean, the local coal power plant can't make artillery shells, but we're not shutting it down...

Only an assumption here, but I would say its due to what to do with the waste. If the waste is useless, then we have to have a place to put it. If it has another use, then obviously we dont have to stick it in a hole somewhere.

Again, totally non-researched, off the top of my head assumption.

Thorium reactors breed U-233, but not as a waste product. The U-233 is consumed to generate power. I'm not sure what the U-233 produces when it undergoes fission but I don't think the result is weaponizable.

Nice specs!

Where does the Thorium come from and how abundant is it?

"Thorium is three times more abundant in nature than uranium. All but a trace of the world’s thorium exists as the useful isotope, which means it does not require enrichment. Thorium-based reactors are safer because the reaction can easily be stopped and because the operation does not have to take place under extreme pressures. Compared to uranium reactors, thorium reactors produce far less waste and the waste that is generated is much less radioactive and much shorter-lived."

http://www.forbes.com/sites/energysource/2012/02/16/the-thin...

Thorium is not a fissile isotope - meaning it can't be used for fission directly. It needs to be transmuted by neutrons into uranium 233 (which is fissile). By this measure, thorium isn't any better than Uranium 238 - which is 99.3% of naturally occurring uranium. So "All but a trace of the world's thorium exists as the useful isotope" - can be applied to uranium also. Uranium 238 is also a fertile isotope - and doing a completely fair comparison, uranium doesn't need to be enriched either... Except the only way we have to convert fertile isotopes to fissile isotopes is to expose them to a sustained, high neutron flux which is typically only economically achievable using enriched uranium (via the naturally occuring U235 isotope). Thorium breeder reactors need enriched uranium as much as uranium breeder reactors. So while thorium has some advantages, I wouldn't say that natural abundance or supply are particularly significant.

[Edit] corrected use of "fissile" -> "fertile"

Or, if you're doing research in the UK, you use a particle accelerator to convert it on the fly. Once it starts you're good to go (you can keep it going using neutron flux in the reactor) so you have the particle beam starter engine :-)

Roughly 3-4 times as abundant as Uranium, according to http://www-pub.iaea.org/MTCD/publications/PDF/TE_1450_web.pd.... To give you an idea on how much energy could be produced with this: A rough estimate shows that if all our current electric energy demand would be satisfied with Uranium, the reserves would run out in roughly 10 years. See http://johncarlosbaez.wordpress.com/2010/09/03/how-long-woul....

This estimate doesn't seem to account for enrichment. For every KG of uranium mined, you get a much lower ratio of enriched fuel.

It shouldn't account for enrichment because thorium is a fertile material (not fissile) just like uranium 238 (99.3% of all uranium). Unenrichced uranium can be used in breeder type reactors just like unenriched thorium.

> rough estimate shows that if all our current electric energy demand would be satisfied with Uranium, the reserves would run out in roughly 10 years.

While strictly correct, this is extremely misleading. Current resources would be exhausted in a decade, but resources are defined as the known deposits extractable under current market prices. Should we actually start using a lot of uranium, the price would spike, which would lead to a lot more deposits becoming economically available. This has almost no effect on the cost of nuclear power, as the cost of the raw uranium isn't a large part of the cost of producing power.

The end game there is when the price rises sufficiently for extraction from seawater becoming profitable. The world's seas have ~1000 times more uranium than conventional ground-based resources.

Nuclear fuels will not run out in this millennium.

How about energy return on energy investment. You have to vaporize a lot of water (of course you will have all those gold, iron, rare metals "waste" which will help the economic case).

Research has focused on other methods:

http://en.wikipedia.org/wiki/Uranium_mining#Recovery_from_se...

The total known ground resources are estimated to be roughly seven times larger than the current mining reserves. So this gives you at most a factor of ten. Of course there are other unrealistic assumptions in those estimates. Realistically you would use other sources of electric energy for instance. I don't now if the Thorium reserves are roughly four times larger than the current Uranium reserves or four times larger than the amount of Uranium that could feasibly be extracted from the ground. In any case, both are only a solution for the near future, that is the next 50-100 years or so. With current technology it would not make sense to extract Uranium from the Ocean, its concentration is $10^{-9}$, it can be commercially extracted from rocks with $10^{-4}$ concentration. It does not possible to filter huge amounts of seawater for such insignificant quantities of Uranium.

That estimate for uranium assumes conventional reactors, which fission U-235. That's 0.7% of natural uranium.

For a real comparison, you should look at fast reactors, which use the rest of the uranium. That takes your estimate up to about a thousand years. But the estimate is looking at economically recoverable reserves, and if the same ore produces a hundred times as much energy, a lot more becomes economically recoverable.

Thorium would be 3-4 times more abundant than that. (But if seawater extraction works out, uranium will have the advantage again.)

If it's 3-4 times bigger than the Uranium, and Uranium will last us 10 more years - Thorium would last us 30-40 years. What to do after that?

If there ever appears a new intelligent civilization millions of years after humanity, they'll be very disappointed to be on an Earth without any Uranium or Thorium!

See my post: https://news.ycombinator.com/item?id=8036690

Uranium will simply not run out. The "10 years" figure stems entirely from misunderstanding what the word "reserve" means in mining.

Also, there is 3-4 times more natural thorium than natural uranium. Of natural uranium only 0.7% is U-235, which is useful in a traditional reactor. Breeders can use all of it. Thorium reactors are all breeders. Assuming only resources extractable at current market prices, using uranium breeders the reserves would last ~1400 years and the thorium reserves would last ~5k years.

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