Can thorium nuclear energy make a comeback?
Can thorium nuclear energy make a comeback?
Nuclear energy gets a pretty bad rap – for good reasons. But thorium, a weakly radioactive element, is hailed to fix all its problems: no meltdowns, less waste, no bombs. We developed a molten-salt reactor to unlock its potential decades ago – but then turned our backs on it. Was that a huge mistake?
Credits:
Reporter: Malte Rohwer-Kahlmann
Video Editor: Frederik Willmann
Supervising Editor: Michael Trobridge
We’re destroying our environment at an alarming rate. But it doesn’t need to be this way. Our new channel Planet A explores the shift towards an eco-friendly world — and challenges our ideas about what dealing with climate change means. We look at the big and the small: What we can do and how the system needs to change. Every Friday we’ll take a truly global look at how to get us out of this mess.
#PlanetA #Thorium #Nuclear
Read More:
Atomic Energy Commission report on molten-salt reactors (1972):
https://www.osti.gov/servlets/purl/43…
Oak Ridge report on Molten-Salt Reactor Experiment (1969):
http://www.thmfgrcs.com/NAT_MSREexper…
Problems with molten-salt reactors:
https://thebulletin.org/2022/06/molte…
World Nuclear Association’s fact-sheet on thorium:
https://world-nuclear.org/information…
3D reactor animation in thumbnail courtesy of Flibe Energy.
Chapters:
00:00 Intro
01:12 Molten-Salt Reactor Experiment
03:40 Power couple
05:26 What went wrong?
07:41 Today’s vision
08:32 The road ahead
Content
7.399 -> Nuclear gets a pretty bad rap.
9.53 -> And, well, there are some pretty good reasons for that.
12.466 -> "In the towering mushroom, Japan could read its doom."
17.113 -> "It was the first step in a nuclear nightmare."
20.669 -> "The Soviet Union has suffered one of
22.304 -> the worst disasters in the history of nuclear power."
26.24 -> "A disaster of unknown proportions."
28.853 -> But...
29.893 -> ...what if we could have nuclear energy without the problems?
34.467 -> No meltdowns.
36.418 -> No weapons.
37.923 -> Oh...and a lot less waste.
40.239 -> Well, there is a nuclear superfuel that's supposed to do all that.
43.789 -> "Let me tell you kids about thorium."
45.625 -> "...thorium..."
46.23 -> "...thorium..."
46.73 -> "Thoooooriiiiuuuuum!"
49.032 -> We've known about it for decades.
50.867 -> "...molten-salt breeder reactors operating on a thorium cycle..."
55.132 -> More than half a century ago,
56.852 -> we built a reactor that was supposed
58.47 -> to unlock thorium's potential.
61.008 -> We desperately need clean energy.
63.149 -> So, why don't we have thorium power everywhere today?
67.096 -> Did we stuff up on nuclear energy?
73.2 -> In the summer of 1965,
75.452 -> scientists at the Oak Ridge National Laboratory,
78.2 -> in the US state of Tennessee, wrote nuclear history.
81.835 -> They powered up a groundbreaking new reactor.
84.267 -> "Molten-Salt Reactor Experiment
86.051 -> went critical on June 1st, 1965."
89.816 -> It was fundamentally different from most other reactor designs,
93.127 -> even up until today.
94.648 -> That's because its nuclear fuel didn't come in solid form.
97.861 -> It was mixed into the coolant, molten-salt,
100.455 -> that circulated through the system.
105.072 -> "I would call the Molten-Salt Reactor Experiment
106.487 -> a stunning success.
108.023 -> It did things in the 1960s that we still can't do in reactors today."
112.081 -> This is Kirk Sorensen,
113.591 -> a self-proclaimed "thorium evangelist".
116.344 -> His company, Flibe Energy, is working on
118.466 -> a modern version of the Oak Ridge reactor.
120.81 -> "We've come up with things that are going to make it easier
122.498 -> and better and safer and faster.
124.362 -> But at the heart of it really is the technology
126.448 -> that was originally put forward by Alvin Weinberg
128.884 -> at Oak Ridge National Lab in the 1960s and 70s."
132.279 -> The vision now is the same as back then:
134.67 -> to generate energy from a neglected nuclear fuel - thorium.
139.168 -> It's a weakly radioactive chemical element
141.657 -> that's three to four times more abundant
143.646 -> in the Earth's crust than uranium,
145.803 -> which is what we mainly use to power reactors today.
148.604 -> But thorium itself can't power a reactor.
151.355 -> And we need to get a bit nerdy to understand why.
154.503 -> Nuclear fuels we use today, like uranium-235, are fissile.
159.299 -> This means when their atoms are hit by a neutron,
161.531 -> they likely split and release more neutrons
164.237 -> that split more atoms and so on.
166.629 -> This nuclear chain reaction produces heat,
169.069 -> which can power a reactor.
171.023 -> But you can't split thorium-232.
173.371 -> It's not fissile, but fertile.
175.798 -> When a neutron hits its atoms,
177.184 -> it usually just absorbs it and turns into thorium-233.
181.135 -> No chain reaction.
182.575 -> Yet.
183.495 -> Because after about 20 minutes or so,
185.33 -> it decays into protactinium-233.
188.115 -> Which, after about a month,
189.475 -> decays into uranium-233 and that does split.
195.093 -> "So, these systems do tend to need a start up,
197.937 -> if you like, a bit of a start up boost or amount of fuel
203.008 -> to get the ball rolling, if you like."
205.534 -> Paul Norman is a professor of nuclear physics
207.705 -> and energy at the University of Birmingham.
210.379 -> "Once that is happening,
213.198 -> we can start to grow in from the thorium
216.061 -> this variant of uranium that keeps the system working."
220.972 -> Now, you could theoretically use thorium
222.949 -> in a whole bunch of reactor designs.
225.093 -> But liquid molten-salt reactors
226.798 -> are arguably the most interesting,
228.795 -> as they, by design, promise unique advantages.
231.944 -> "It tries to kind of rewrite some of the initial rules."
236.15 -> For a start, they'd be pretty safe.
238.546 -> They couldn't melt down
239.562 -> since the nuclear fuel is already molten.
242.369 -> And even if it did become too hot,
244.361 -> most designs would have what's called a freeze plug.
247.141 -> This would melt at a certain temperature
248.99 -> and the nuclear fuel would just drain into cooling tanks.
251.497 -> "The beautiful thing about it is it's physical.
253.846 -> It's baked into the laws of chemistry and physics themselves.
257.31 -> It's not something we have to go and append on
259.438 -> or try to engineer later.
260.934 -> It just is that way."
262.304 -> Molten-salt also has a fairly high boiling point.
265.598 -> So, you could run the reactors at comparatively
267.694 -> high temperatures and low pressures.
270.036 -> This would make them efficient
271.331 -> and potentially cheaper to build.
274.066 -> Molten-salt reactors would also burn up a lot of their fuel.
277.225 -> There'd be less radioactive waste coming out
279.329 -> than in conventional reactors.
280.924 -> And much of it would be mostly gone
282.827 -> after hundreds instead of thousands of years.
285.63 -> And in thorium molten-salt reactors,
287.303 -> you'd get virtually no plutonium,
288.982 -> which can be used to make weapons.
290.786 -> Though, strictly speaking,
292.014 -> that would also be possible with uranium-233.
295 -> Still, all this really seems like molten-salt reactors
297.555 -> and thorium are a match made in heaven.
299.951 -> Which does make you wonder,
301.784 -> if the people at Oak Ridge were already onto this way, way back,
305.052 -> why aren't molten-salt reactors, like, everywhere?
308.395 -> The Molten-Salt Reactor Experiment
310.396 -> ran at full power for more than 13,000 hours
313.374 -> and became the world's first reactor
314.921 -> to run on uranium-233 produced from thorium.
318.54 -> The people there even started calling it
320.093 -> the Mighty Smooth Running Experiment.
322.486 -> But then, government officials pulled the plug.
325.448 -> What happened?
327.119 -> Well, for one,
327.906 -> the experiment didn't always run so "mighty smooth".
331.297 -> "The experience with the molten-salt reactor
335.642 -> experiment in Oak Ridge was pretty bleak."
340.589 -> This is M. V. Ramana,
341.792 -> a physicist who researches nuclear policy.
345.017 -> "The reactor had trouble even reaching its designed power level.
351.439 -> It then did not run smoothly.
353.974 -> It was shut down a lot.
355.87 -> And in the four years that it operated,
358.869 -> it operated for only about 40% of the time."
361.77 -> There were also questions about
363.241 -> the materials in touch with the liquid fuel.
365.72 -> The alloy specifically designed to withstand extreme heat,
368.843 -> corrosive salts and radioactivity showed cracking.
371.909 -> It also didn't cope well with higher doses of neutrons.
374.805 -> And there were concerns that a radioactive gas by-product
377.553 -> could leak into the environment.
379.273 -> Tritium is so volatile
380.581 -> that it could escape through parts of the reactor.
382.89 -> "When you build something for the first time,
384.952 -> you don't get everything right.
386.309 -> You do find issues.
388.039 -> That's why we build experiments."
389.783 -> All technical issues aside, though,
391.411 -> the real reason why the program
392.931 -> was ended was a different one.
395.131 -> The Oak Ridge director Alvin Weinberg wrote:
397.878 -> "Our problem is not that our idea is a poor one,
400.765 -> rather it is different from the main line."
403.832 -> And the "main line" was another type of reactor,
406.907 -> the sodium-cooled fast breeder reactor.
409.544 -> It was eventually favored over the molten-salt reactor.
413.332 -> "There were a lot of good reasons for that.
415.149 -> That was a much better tested design at this point.
418.382 -> There had been problems there, too.
420.418 -> But those were not as apparent
422.645 -> as the problems with the molten-salt reactor."
425.164 -> You might come across other explanations
427.429 -> as to why the experiment was stopped.
429.787 -> It was the time of the cold war, after all,
431.665 -> and thorium molten-salt reactors
433.367 -> wouldn't have given you easy access to plutonium.
436.311 -> Also, the nuclear industry was making
438.211 -> a pretty good buck on conventional reactors.
440.729 -> Why would it have wanted
441.665 -> a more efficient design that breeds its own fuel?
444.861 -> It's hard to say how much or how little truth,
447.014 -> if any, there is to these.
448.6 -> All the same,
449.4 -> the Molten-Salt Reactor Experiment ended in 1973.
452.539 -> "We would have had a very, very different world
455.036 -> had we proceeded with this.
456.522 -> But, you know, like they say,
457.813 -> the best time to plant a tree is 20 years ago.
459.662 -> The next best time to plant a tree is today."
461.742 -> And today, there's a whole bunch of companies
463.424 -> working on different molten-salt reactor
465.307 -> designs with different features.
467.616 -> There are, for example, concepts to fuel a molten-salt reactor
470.488 -> with radioactive waste from conventional reactors.
473.963 -> Kirk Sorenson's company, Flibe Energy,
475.837 -> is planning to build a small test reactor
477.897 -> before the end of the decade.
478.956 -> "We've gone through a number of generations
481.011 -> of nuclear reactors and other technologies.
482.944 -> Molten-salt's been through one initial generation
486.277 -> and it's time to continue on and understand
491.005 -> these advantages that can be infused into the design."
495.462 -> China is planning to start up
496.856 -> a small molten-salt test reactor on the edge of the Gobi Desert.
500.669 -> And India, home to the world's largest thorium reserves,
503.584 -> is also working on reactors
505.456 -> to utilize them as part of its long-term nuclear strategy.
509.068 -> So, is it second-time lucky for molten-salt reactors and thorium?
513.019 -> "You know, there's one level of it, which is sort of
515.241 -> talking and saying you're going to do things.
519.307 -> But the much more important
521.154 -> aspect is to actually be doing it."
523.655 -> And, well, this might prove a lot harder
525.982 -> than flashy 3D animations suggest.
528.885 -> Yes, molten-salt reactors are meltdown-safe.
531.354 -> But that's not the only thing that can cause a nuclear accident.
534.323 -> "Any good regulator will be
536.289 -> asking a lot of questions to a designer.
541.342 -> 'How will this reactor behave if there's a fire?'
544.064 -> 'What if there's an earthquake?'
545.195 -> 'What if your operator
546.983 -> presses this button instead of that button?'
549.088 -> Those are not easy questions to answer."
551.514 -> Regulators might require changes to reactor designs,
554.406 -> which could make them more expensive to build.
556.348 -> Which would kind of take away
557.782 -> one of molten-salt's biggest draw cards.
560.226 -> And remember the cracked components at Oak Ridge?
562.942 -> Well, problems like these need to be solved as well.
565.498 -> Not just on paper.
566.5 -> But in a real, radioactive environment.
570.54 -> "Under those sorts of conditions, of course,
572.477 -> it's harder for materials to bear up.
575.034 -> So, there are almost invariably things like that
577.861 -> that have to be further researched and developed
580.958 -> and really that sort of confidence made
585 -> that they can work okay within the extreme environment
588.669 -> of the reactor that the materials sit."
591.462 -> And then, of course...
593 -> ...money.
593.976 -> There needs to be, like, a lot of it.
596.283 -> To fund all the research, for one.
598.127 -> But also to build up an entire infrastructure
600.632 -> and supply chain from scratch.
602.623 -> "In the last couple of years, we've had
604.533 -> more capital than we've ever had before
606.672 -> and we've proceeded much faster
608.297 -> than we ever had before.
609.173 -> But it's still a very, very small amount
611.834 -> compared to where we need to be."
614 -> So, let's be clear.
614.946 -> There's a lot of catching up to do.
617.041 -> Commercial thorium molten-salt reactors
618.861 -> are still years away, at least, if they ever happen at all.
622.282 -> So, we shouldn't let this dream distract us
624.189 -> from climate solutions we have available now.
627.531 -> Did we take a wrong turn in the 60s?
629.766 -> Well, only the future can really answer that.
632.436 -> By solving all the challenges
634.133 -> the team of Oak Ridge invariably would have run into.
640.904 -> "What's your take on thorium and molten-salt reactors?
644.011 -> Are they the power couple that will help save the climate
647.449 -> or nothing but a pipe dream?
649.404 -> Let us know in the comments and
650.64 -> don't forget to hit subscribe
652.006 -> because we have a new video for you every Friday."
Source: https://www.youtube.com/watch?v=Km6kqykX900