Pocket Particle Accelerators Like This One Could Bring Safer Nuclear Power to Neighborhoods

pocket sized, huh...

"Thorium reactors would not melt down"
It's a nuclear reaction and no safety systems are foolproof. They will design them to feed power into themselves I guarantee that. Most meltdowns are caused by loss of power to systems that control the reactions and they cant guarantee that won't happen. If it can happen it will.

It also produces uranium and other materials as waste. A minor fluctuation in power could split that waste rather than fuse materials and you've got a meltdown on your hands.

@corwinb It is a fission reactor, not a fusion reactor and thus would not produce any uranium. However, I do agree that a meltdown is still possible even though it says it requires an external input to produce fission. Fission reactions are chain reactions; after the initial input they are designed to power themselves until further external input stops the reaction. If it is not self sustained than it won't have very much of a risk of meltdown but it would also produce very little energy as it would require constant external input to keep the reaction in progress.

@Smith2031 & corwinb

The possibility of a meltdown with a thorium reactor is extremely improbable. Why? Thorium reactors need a CONSTANT input of an outside energy source. The particle accelerator featured in this article produces the high energy particles that will excite thorium. If that flow of particles is stopped, or the accelerator itself is shut off, the thorium reaction stops.

Thorium, unlike uranium can't go into a self-powered meltdown. Even should a thorium reactor "partially melt down" which is highly unlikely, as soon as that meltdown damages the particle accelerator or the energy feeding that particle accelerator, the meltdown itself will stop.

In fact, in a way, thorium reactors are over-unity machines in that they output more energy than what is input. They do use a nice amount of energy to feed the particle accelerator, to excite the thorium and produce energy, but they ultimately produce more energy than they consume. Machine might be the wrong word b/c that implies they are doing work, and they are not, but they do produce more energy than consumed.

Uranium on the other hand it just raw energy, kinda like fire. Most uranium reactors are some version of a steam turbine generator, the heat output of uranium converts water to steam that turns a turbine, producing energy. That steam is condensed, and either fed back into the system (for a limited # of times and eventually stored) or its outright stored. This contaminated water is one portion of nuclear waste.

So guys, a few things... Any heavy element fission reactor that produces enough power will be capable of melting down. Why? DECAY HEAT. Shutting down a nuclear reactor is really easy. All of the Japanese reactors shutdown at the start of the earthquake, that wasnt the problem. Even if a reactor is shut down, it still produces heat from the super radioactive fission products that are a result of fission. For U235, this amounts to ~7% of the long term steady state operating power. Depending on Thorium's spectrum of fission product yield (something I bet is not well characterized anyways) it should be about the same. If you have a 1000MW plant then max decay heat would still produce ~70MW, still a ton of heat. If you cant continue to cool, the plant heats up until the core melts. Though my knowledge is with pressurized water reactors using highly enriched U235, I venture to say that you would still have the potential for a meltdown.

Uh, none of this matters because the oil gods will never allow it.

LOL @ old-scratch

i agree. with the money currently in oil this seems unlikely on a mass scale.

@Smith2031 FYI,you switched the two.FUSION does not produce Uranium.FISSION does.The thorium reactor is,I think,a kind of fission reactor,but more complexe and apparently less dangerous(remain to be seen).But anyway,as fusion reactors(the TRUE close-to-totally-safe nuclear reactors,and one possible future of energy)are still far away,any fission update that can replace the old reactors are good.I guess.Better than fossil fuel anyway.If there is no accidents.

@brainwood

Thorium is not U235 its apples to oranges.

they work nothing alike on almost any level I can see so the assumptions you're making make little sense to me.

sure there will be byproducts but not likely at the high energy levels of the ones made by U235 so they won't make as much heat nor make heat for as long.

Remember that the problem in Japan wasn't the heat of the fusion products but the decay heat of the U235 itself. That self generating heat caused it keeps getting hotter and hotter as time went on. I would expect that Thorium doesn’t do that or we would be using that instead of going through the trouble of making highly enriched uranium. so the Thorium itself should act as a heat sink small amount of heat made by any fission byproducts

whatever heat is left in the system after its shut off should only fall over time not raise like a fusion reactor.

... Duuude.... What is a melt down by your definition? is it jsut when things go bad? The more radio active elements (insert here) radiate so much heat that they have to me activly cooled.... When power is lost and all the coolant (heavy water) evaporates the solid metal heats up drasticly and actually melts. It can reas high enough temps to melt though the foundation and into the ground. Bad stuff and kinda cool. So thorium isnt not goin to do this. Not in its properties to do so.

No research is bad research. The japan facility was really old any how. 40-50 years old. Feel free to correct me because that is what science is all about. No research is bad research. I still like polywell fusion that is funed by the navy.
Tell you what id love to have this device just so i can say i have an Iron Man 2 particle acceterator in my back yard ;-)
Have a good day yall and have fun reading

oh ps I like how you can split atoms and make heavier elements...Your sir must be a grand master wizard ;-)

Am I really the only one who looks at this an thinks "Whoa, Iron Man."?

Not another one of this nuclear crap... There's no guarantee that thorium is completely safe. Plus the nuclear technology is just expensive as hell to research, this money is better spent on renewables. The nuclear energy dream always start as some fantastic ideal energy that supposedly powers up the entire world's electricity at a fraction of the cost, but then it ends up as a gigantic money-sucking mess. It has already happened in Japan.

Yay for nukes, but I seem to recall that "conventional" nuclear power was expected to be too cheap to meter. Why wouldn't all of the same very expensive safety, security, control, regulation, storage, transportation, and transmission issues apply to this technology, as well?

Thorium reactors operate as a fission reaction, NOT fusion; there is a huge difference. Also, most thorium reactors operate as breeding reactors (like the CANDU reactors in Canada), meaning that they produce more fuel than they initially have. It doesn't specify in the article what type of reactor it is, it specifies the neutron source(the particle accelerator). If it works like a molten-salt breeder reactor, that would be awesome! Of course there are risks; accidents can still happen. @gorash: the problem with PV's is that no matter what you do, you will never ever ever be able to produce more than one free electron per photon that hits the surface of the PV. Ever! That's what Einstein told us in 1905, and guess what!? He was spot on. So even though we are not near that efficiency yet, once we near 100% efficiency(gotta find superconductors that hold up at normal temperatures), that will pretty much be it. With nuclear, the sky is the limit. Fission has much room to be improved, and someday we will be able to harness Fusion and energy will e changed forever.

Tidbits: Nuclear decay process of Thorium-232: Th-232 absorbs a slow neutron which produces Th-233 --> beta decays to Pa-233 --> beta decays to U-233 which is non-fissile material!

I really feel the need to point a few things out.

There are NO commercial fusion reactors. If you are describing events like what has happened in Japan and using the word fusion, you are wrong.

The artical describes a fission process, where neutrons are used to split atoms of thorium. Fusion does not split atoms, it combines them. If you are using the word fusion to describe anything from this artical, you are wrong.

Fusion, as mentioned, is a process of taking 2 lighter atoms and combining them into 1 atom. Most fusion research revolves around fusing hydrogen into helium because hydrogen is abundant, its safer than radioactive elements, and its easier to fuse lighter elements than it is to fuse heavier elements like uranium and thorium. So if you're using words like uranium or thorium to describe the fusion process of generating energy, you are wrong.

Bullet point: there should be no mention of the word fusion in any of these comments.

I feel better now.

@sonnyboy
I thought about that too, lol!

@everyone
WTF?!? Is it fission or fusion now?

According to Wikipedia, Thorium 232 absorbs a neutron (some sort of fusion), then becomes Uranium 233, which is fissionable.

So please stop screwing up about if it is fusiono or fission, and read a bit about the subject before posting stupid comments!

Have a great day,
Kherzhul

EDIT: I am really sorry, it absorbs a proton, not a neutron, silly me!

fission or fusion: As IcplTom said there are no commercial fusion reactors but as dhagan said (but did not categorize as fusion; I believe you meant "absorbs a proton" dhagan) there are fusion processes in our typical fission reactors. Check wiki on the decay of U-235 and you'll see that Thorium is a intermediate product to U-235 decaying to U-238.

Fusion reactions for elements above Iron typically absorb energy, those below typically yield energy. To date, the energy required to create the conditions for light element fusion have required more energy in than we can harness from the reaction (when that changes... WOOHOO!).

The melt down question is really about whether any of the intermediate steps generate enough self-sustainable fission product (there may be NONE of it) from start to finish. I have no idea of the entire range of element-isotopes produced but guess there are many.

On the face of it though, this is one of the most hopeful articles I've seen on nuclear energy for a while. Many of us who have prayed to the God of Fusion (Hydrogen to Helium) for decades have only had silence in return. All the best to the Brits, may the Gods of Fission smile upon them.

@Smith2031 -- Someone needed to correct corwinb, but you are not the person to do it... Why? Because you don't know the difference between fission and fusion reactions.

To wit; fusion reactions, such as the nuclear process that occurs in a star, like our Sun, FUSES lighter elements into heavier ones. Ie; hydrogen fuses into helium. Fission reactions are just the opposite of fusion; fission reactions split heavy elements into lighter elements. Ie; uranium into barium and krypton.

To all the people trying to point out trying to point out the inaccuracies being uttered by people confusing fusion and fission; THANK YOU! You're lone voices of intelligence in a wilderness of ignorance.

To all the people who think a thorium reactor can "melt down", you did NOT read the article, but if you did, you obviously didn't understand hardly any word you read.

@gorash -- You're simply ignorant beyond measure. As people with an understanding in physics: ie; engineering, chemistry, have been trying to get the ignorant to understand, "green" energy isn't GREEN. It consumes more resources in land and materials than any of the traditional methods of generating electricity.

@gorash
your a fool, renewable energy will never beable to replace fossil fuels, the only way to replace it is through nuclear power, there are safe and reliable nuclear technology out there, but everytime someone like you comes around and hears nuclear you think of the incredible hulk and japab and think, "NO NO we can't use nuclear energy its dangerous" yes it WAS dangerous, 30-40 yrs ago, now we have very safe technology that we aboslutely need to be using......you fool

@Smith2031
Hit ctrl+F and type in the word fusion. Scroll back to the top and type the word fission. The article says it's a fusion reactor. Any fission reactor will melt down whether there is input energy or not because fission is a chain reaction whereas fusion requires a sustained input of force.

For those others saying it doesn't produce uranium you should look up Thorium fuel cycle.

Aww, look at all the sensitive people who can't deal with the facts...

The fact is that there are 10,000 times more sunlight than we need to power the entire world's electricity. And as the solar panel technology improves, and the manufacturing cost decreases as it is happening right now, it just makes economic sense to go solar, while nuclear and fossil-fuels' cost will skyrocket in the future. Renewables are inevitable, and it just makes sense. Sticking to out-dated, polluting 19th century technology like fossil-fuels and nuclear is not going to cut it, and they're not going to save us.

Continuing with nuclear is just an act of insanity, since we haven't even figured out a way to deal with the radioactivity and nuclear waste. Once they have figured out a way to properly deal with radioactivity, then we'll talk. Otherwise, it's just another Fukushima and Chernobyl waiting to happening. And no, nuclear plants are NOT "safe"... rofl. You should really stop drinking the kool-aid offered by the nuclear industry, and stop buying into their marketing hype.

Besides, like I said, nuclear is just expensive as hell. And it takes DECADES just to build new nuclear plants. So even if we somehow wanted to use and expand nuclear, it's just not a viable solution. To power up the entire world with nuclear alone it'd require 1000's of new nuclear plants, and that's just not possible, even just from a financial point of view. Plus if we accelerate the pace of nuclear power then the precious uranium will deplete in as early as 40 years. Anyone who thinks that nuclear is the future is insane and has not done their homework.

@gorash

Nuclear plants aren't safe, huh? That explains why almost a quarter of Europe's power has been supplied by them for decades now without a single incident, not even with the older plants. Mmhmm. Yep, that's unsafe all right. Sounds to me like you're the one drinking the kool-aid here, only from the solar power industry, instead.

While it's true that the sun produces way more energy than we could possibly use at once, harnessing it on a large enough scale to be our ultimate energy solution is simply not possible yet. For that, we need to start working on orbital solar power generators that beam energy back down to Earth, so that we can keep the power supply flowing 24/7. Our current technology level isn't anywhere near good enough to produce truly efficient solar panels right now, and besides, if the things are on land, they're subject to cloudy weather and will always shut down at night. That's not gonna cut it, no matter how sensitive we make them or how much we spread them around.

Anyway, I don't think nuclear fission is the future of power generation, either, simply because the fuel is not the easiest to obtain. It's a nice stopgap, but nothing more. For the long haul, give me either nuclear fusion or something that harnesses interstellar radiation. Nothing else is going to cut it if we ever want to get off this rock and move to other plants.

Again. It doesn't make a damn. Modern industrial civilization will end when we squeeze the last drop of oil from the earth and dont have the energy needed to build new infrastructure. The people in power right now could give a rip because they're withered old white men that will be dead in 20 years at best. Our entire modern society is started with oil and it will end with oil.

@frong Just because we don't hear anything in the mainstream news about severe nuclear accidents on the scale of Chernobyl and Fukushima doesn't mean that there aren't dozens of small to medium nuclear plant accidents occurring every year that could have lead to another Chernobyl and Fukushima.

And we can store the energy in nano-engineered fuel cells, which are already available today.

Actually, you don't hear about them because they don't happen. Yes, there are mistake but very few ever get.reported because the safety masures work as intended, so no harm done. Yes, nuclear is dangerous, but even after Fukushima, which was bad, all the lives and environmental damage caused by coal mining and its missteps makes it no more than a drop in the bucket.

Also, it is a form of fission, but itvery different from the more standard ideas of a fission reaction, because this one requires an accelaratorto start and maintain the reaction and the reason meltdown risk is mini. Power failure is the main cause of meltdown and if the accelerator loses juice, there's no more reaction.

Relevnt link:
www.world-nuclear.org/info/inf35.html#c

As for solar, I agree it would be optimal, if it were economically feasible, which it is not currently. It probably won't be til we can get them into space, as a previous poster stated. Current solar cell and battery tech simply isn't. Efficient enoug, or cheap enough, to provide continous power through the entire day for an average person. Not for a couple of decades still. It would be awesomeif if smeone started buildng.sunsats sometime in my lifetime, but I'm not going to hold my breath about it.

@Shooky56 and @kherzul: There is actually on fusion taking place. Fusion is when two elements combine to produce a new element. ex. hydrogen combining with hydrogen to create helium. It's the basis of nucleosynthesis! Awesome cool! Anyways, the thorium fuel cycle consists of Thorium-232 absorbing a slow neutron(not proton) to become thorium-233. If it absorbed a proton, it would become protactinium(i believe. whatever element has 91 protons). The second step in the thorium fuel cycle is the beta decay of thorium-233 into protactinium-233. This is not fusion; it is nuclear decay (yes, it does involve the absorption of a proton, but it is not two elements combining). The next and final step in the thorium fuel cycle is another beta decay into uranium-233, a fissionable fuel. tadah!

I love PV's. I think harvesting energy from light is wonderful...however, if you truly understand what is going on inside on a nuclear scale, i don't understand why anyone wouldn't want to go nuclear! You are adding a neutron to a nucleus to cause instability and force it to split into two, releasing gargantuan amounts of energy! Come on now, don't tell me you aren't impressed by something so small!

@Maybe Please stop kidding yourself and everybody else... If you do a simple Google search, then you will see that there are hundreds of nuclear accidents occurring every year all over the world. I mean that's the problem with you nuclear folks, you think that nuclear is perfect and has no flaws, and completely ignore the dangers of nuclear. You just cover your ears and go "la la la la, I cant hear youuu, nuclear is safe, safe, safe, safe because I say that it is safe so it must be safe!" Then you go ahead and ignore all the warnings that people make against the nuclear plants and let something like Fukushima happen.

And after Fukushima and Chernobyl, we KNOW that it isn't safe. We KNOW that something CAN go seriously, catastrophically wrong with nuclear. There is no denying that nuclear is not safe by any chance. Please, so stop fooling yourself.

@dhagan If you truly understand the effects of this thing called radiation released from the nuclear reaction which are harmful to humans, then I don't see how you would WANT to go nuclear. You have only bothered to look at all the good things about nuclear, but you ignore all the bad ones, such as dealing with potential radiation releases, which would potentially be catastrophic to us human species and the world. Radiation released into the environment would be IRREVERSIBLE, as it would remain in the environment for 100's, 1000's, or even millions of years. The fact is that we haven't even figured out a way to deal with all the radioactivity. Nuclear is still an experiment that has pretty much failed. We should not be using nuclear until we have come up with a way to clean up the radioactivity. Mindlessly promoting nuclear and ignoring its dangers that it poses to the humankind is just plain irresponsible

I mean, Fukushima has already released plutonium, which may very well last in the environment for a million years. It has also released cesium, strontium, as well as many others which will last for centuries. And they all harm our DNAs, which will cause cancers and gene mutations. Is this really the kind of stuff that we'd want to leave behind to our children and their grandchildren? Do we really want to give them cancers and defective genes? Do we want them to have failing organs and shorter lives? Do we really want to leave something that is irreversible into the environment, something that there is not even a way to clean up, forever? Just because we need to use some energy, right now? How can you not think that this is an act of insanity?

So please... just think for yourself about the dangers of nuclear, and think about the others who will suffer from it as well. Nuclear is NOT all peaches and roses. There are many disadvantages to nuclear, and they are immense. They are not worth the risk to merely power up our electricity.

@gorash Do you even know how photo-voltaic cells work? If not, please exit discussion. Not once did I preach nuclear energy for all! I simply asked how anyone who actually understands physics, or is simply amazed by the cosmos we survive in, could not be absolutely impressed/amazed/in awe of the sheer energy that something on the order of angstroms can possess.

Judging by your shallow discussion of half-lives, I am quite sure I know much more about radiation and its effects than yourself. However, it is quite obvious we hold different views on the human species, earth, and cosmos in general. I see no reason as to why we are a divine species.

Also, how on earth did you reach the conclusion that nuclear is a "failed experiement?"

You didn't merely say you were impressed, you said "i don't understand why anyone wouldn't want to go nuclear!" Your words, not mine. So stop acting like you didn't say what you just wrote.

And shallow discussion, how? It's obvious that you are ignorant of the effects of radiation. It's not shallow at all. Plutonium are halved every 24,000 years, and cesium and strontium are halved every 30 years. It would take many turns for them to completely disappear. Radiation are harmful to human DNA. Is this wrong? So how is this discussion any "shallow"? I'm just stating scientific facts.

You are trying to weasel yourself out of the discussion now by bringing up a lot of irrelevant points, but you have not answered anything other than to come up with some vague idealistic opinions. Why can't you at least stick to what you actually said?

I killed kenny.

why is it when ever some says nuclear you get nimbys yelling to shout out any talk about it? if some one says thay want to research on it you get people will block it from happening. from what i read so far thats what gorash wants.

I don't think that we need nuclear, we never did as it costs too much money and I don't think that it'll save us from the energy crisis. The only thing that they should be researching is how to get rid of the radioactivity... I mean, it's ridiculous that there are nuclear plants operating when we haven't even figured out a way to deal with all the leaked radioactivity and the radioactive waste that they have produced.

@gorash
technology from 40-50 yrs ago is unsafe, thats a given, but current technology that we have now? very safe, with up to 90% less nuclear waste, and even then some of that can be recycled by other reactors, google Liquid sodium thorium reactors, very cool stuff. Solar, wind, geothermal, tidal etc. will not and cannot sustain our current energy appetite and growth unless there is a dramatic change in the way we use it, like space soalr farms, but that is unfeasible right now, the current solar cell is just not that efficeint in 20-30 yrs maybe, but as of right now no. And we are going to need something else in between there, and nuclear is going to have to do it. pull your head out of the sand and stop lying to yourself and us

Lol, 90% less nuclear waste, since when? Recycle? Sorry, still not possible without the fast-breeder reactor, which is not available anywhere in this world. Thorium reactors? Not even a currently available technology... yawn.

You need to do better than come up with some obvious lies and BS.

There is a startup company in Alambama right now (Blige) that is going to develop the Liquid Floride Thorium Reactor (LFTR). They hope to have a prototype up and running by 2015.....yawn.

When a technology (such as we have now with nuclear) isn't working so well, you go back to the drawing boards and make it better, which we are doing. Why should we believe that humankind is not capable of advancing nuclear energy technology to the point where we largely resolve the existing problems and we can trust it? LFTR is a sizable step in that direction.

Those who are shaking their collective heads "no" to nuclear have no faith in us as a species who are capable of resolving problems involving nuclear technology (or anything else). I for one do not lack that faith.

If Fukushima and Chernobyl were LFTRs, those disasters would not have happened. We have only to make the technology better and safer rather than abandon it.

Dear D13: Once again, you are one of those who lack faith in humankind's ability to innovate and solve problems with his brain power. Mankind never has problems per se, just challenges waiting to be overcome.

1) We have been using biotechnology to increase food production worldwide for years now, and it has succeeded in reducing food shortage problems to a significant degree throughout the world. And it is still going on.

2) We don't necessarily have a food shortage problem today, we have a food DISTRUBTION problem where all available food is not evenly distributed. That has nothing to do with depletion of resources. Too much food here, too little there.

3) I suppose you probably have heard this before and won't like hearing it again, but here goes: The manmade global warming theory is largely a crock. It's not that CO2 has absolutely no effect on climate. It's just that the climate alarmists have grossly exaggerated it. CO2's effect on climate is miniscule. Today's tempuratures are well within the range of the Earth's long historical climatic norm and there is no solid scientific evidence that Man has had much to do with it. If you would bother looking, there is a lot of scientific evidence to support this. There is a lot of grant money to be made ($4.5 billion from the Federal Government alone) which gives the climate alarmists plenty of incentive to promote climate alarmism. A heathly grant check trumps honest science every time. And the UN's IPCC has a green agenda too which gives them an incentive to promote this fudged crock as well.

3a) Recent reports from NASA and two other sources are telling us that the sun appears to be going into an inactive or hibernation mode. In the past, this seems to have happened in concert with the Earth's cooling (the Earth cooled from 1945 to 1976 also -- any explanation for that?), and there are some signs that this is beginning to happen. We have had below normal temps where I live all spring -- and I'm getting sick of it. If the earth cools considerably because of the sun in the years and decades ahead, climate alarmists are going to have a lot of explaining to do.

4) According to the demographers I've heard from, the human population on this planet is going to level off around 2050 or so -- just 39 years from now. Once it does, global starvation will become a non-issue (if it ever was an issue).

5. There is enough thorium in the earth today to provide the planet with much of its energy needs for centuries if not a millenium with LFTR technology. Hopefully, by then we will have discovered the secret to fusion. Thorium is 4 times more plentiful than uranium in the Earth and provides much more energy per ton than uranium. And LFTRs burn thorium far more efficiently than today's reactors burn uranium (that is why there is so little waste -- 1%). So yes, how about those Thorium reactors!

6) D13, do yourself a favor: Stop listening to the green treehugging gloom-and-doomers. The only real weapons they have to wage their war on the status quo today are lies and fear mongering, and they use them all too well on those who are gullible enough to believe. Back in 1968, a book came out from a gloom-and-doom Greenie. It was called "The Population Bomb" (by Paul Erlich) and predicted that we would be experiencing near-total depletion of our global resources by 2000 or so from continued population growth. This was supposed to result in widespread famine and wars for the remaing resources. Well.... its 2011 and I'm still waiting. According to Erlich, we should have run out of oil years ago. So don't go through life with the pessimistc outlook on the future that you appear to have from listening to the wrong people. Be happy.

Lol, if a mere startup company can start up a thorium reactor in just 4 years, then we would already have 100's of thorium reactors by now. The fact is that they've already been working on thorium for decades.

The proponents of nuclear energy always seem to ironically know so little about nuclear energy...

The fact is that nuclear is already dead, and it has already been in decline even before Fukushima. Nuclear has stalled and remained stagnant since the Three Mile Island and it has never recovered. Nuclear is just too expensive and dangerous, and it makes zero sense to nuclear. Why risk people's lives and humanity when there are better, cheaper, safer options other than nuclear.

gorash:
1) Scientists have not exactly been working on thorium for decades. The reason why thorium LFTR reactors are just getting attention now are twofold:
a) During the Cold War in the 1950s and 1960s, scientists realized that thorium reactors like LFTR would be no good for producing weapons grade material (plutonium) for making nuclear weapons. So thorium was largely dropped except for a LFTR that was operated WITHOUT INCIDENT for 4 years (1965-1969) at the Oakridge National Labs in Tennessee. They would even shut it down on Friday night before going home for the weekend and then start it back up again on Monday. Meltdowns and leakage NEVER happened.
b) By the end of the Cold War in 1989-1990, the new generation of nuclear scientists were not being taught about thorium-fueled nuclear energy in school due to the fact that it had been dropped decades earlier (see 1a). No one was developing it because no one was aware of the technology until the scientists at this new startup company recently revived it.

2) Nuclear is not dead. There is a new reactor being built right now in Georgia. A utility in Florida has submitted the paperwork to the NRC to build a new reactor there as has (I think) a utility in Texas. India and China are working on thorium-fueled reactors (China is working on LFTR and India on solid fueled ones). A new reactor started up recently in Pakistan and Russia is still investing in new nuclear technology R & D. Doesn't sound dead to me.

3) I have been reading considerable info on LFTR (have you?) and it sounds pretty safe to me. Scientists at the startup company as well has many other knowledgable scientists are pronouncing it much safer and worth the investment. They also say that it is even cheaper to build than coal plants (which LFTR should replace) because it is so much smaller and compact and the parts can be manufactured on an ASSEMBLY LINE. The thorium does not need to be enriched first which reduces operating costs. With all of this said, please explain what the design and engineering flaws are in LFTR (that you apparently know about) that presumably make it so dangerous. If there were any, do you think that these scientists and engineers would put their careers and reputations on the line like this? I know I wouldn't. Don't judge new technology through the lens of the old problematic technology we use today. It's a little like comparing apples to oranges.

4) What other cheaper, safer technology are you talking about? Geothermal is good, yes, but only certain areas out West are good for it. If you mean wind and solar, it has already been stated in a previous post that wind and solar are not capable of replacing all the energy we get from fossil fuels, nuclear, hydro, and others. I don't know of ONE scientific report that says they can with current technology. Maybe advacement in technology would help with solar (like Concentrated Solar Energy using mirrors or collecting solar energy from satellites in space and sending it down to Earth). But I still doubt it can completely replace our current energy sources because the sun just does not shine everywhere 24/7.

Or just build LFTR power plants which can also fission thorium, but without the big, complicated, expensive, and unreliable particle accelerators.

Now that's a pointless heath robbinson device if ever I saw one.

it took relatively little research to find that not only is thorium based nuclear plants a good safe energy provider but would also be useful to rid ourselves of the plutonium waste that we currently must store for thousands of years. seems like a win-win kind of deal to me

look it up gorash, http://en.wikipedia.org/wiki/Molten_salt_reactor

the only reason we don't see expansive use of nucelar tech. is because of NIMBY's like you. If you would open your mind and consider nuclear you would see how valuable it is....

Yes, how dare people detest having something as dangerous and polluting as nuclear plants in their backyards... I'd suppose YOU wouldn't mind having nuclear plants in YOUR backyard, and we should also dump all the radioactive waste in your backyard, too! Brilliant!

Face it, stop blaming the lack of nuclear expansion on people, the fact is that nuclear has always been too expensive and too dangerous. Get with the program, and face the facts and reality, because the reality is not going to change.

I am one of the designers of EMMA and am working on some of the experiments being carried out on it. I'd like to clear up a few items of confusion about this experiment, and the thorium reactor technology that we think could be improved by the results we obtain.

Firstly, EMMA is a *test* accelerator to examine a new concept that would make high power accelerators cheaper. EMMA is not a high power accelerator in any way - that's not its purpose it all. To do dynamical tests we circulate electrons, which aren't much use in a full-scale machine but let us do the experiments more cheaply, partly because we can make EMMA smaller. A full-scale proton accelerator suitable for driving a thorium reactor would be much bigger, perhaps 30m across, but small in comparison to the complete power plant. With current technology (linacs) the accelerator would have to be hundreds of meters long, so this is a big improvement. We also think FFAGs have the potential to be much more reliable, but this isn't proven yet.

Thorium power plants are fission reactors, not fusion reactors. You can't fission thorium directly, it has to be converted (bred) into Uranium-233 (U-233) first. You do this by mixing in a little U-235 or Pu-239 as a 'starter' into the reactor core, at least in the first few reactors of this type until you've generated an inventory of U-233. U-233 can't be dug out of the ground, because it doesn't occur naturally in any significant quantities like the more familiar U-235 and U-238. Why do you want a Thorium power plant? Because if you do it this way you can breed lots of fuel and generate electricity for thousands of years, at least in theory.

U-233 is harder to handle that U-235 in current reactors, partly because of the associated U-232 that comes for free when you make U-233. U-232 is nasty, and stops terrorists stealing your U-233 and turning into bombs. But it also makes fuel handling and reprocessing more difficult. The nuclear industry isn't really interested in Thorium because we're still burning lots of coal and oil, so there's no short-term prospect of running out of mined U-235. If we decarbonised our electricity supply we would run out of U-235 very quickly unless we can extract Uranium from seawater, which is possible but unproven on the large scale.

Thorium plants based on lead-cooled reactor technology let you destroy nuclear waste from existing power plants so you don't have to bury it. But lead-cooled reactors are tricky (only the Russians have ever run them properly), and 'topping up' the neutrons using an accelerator makes these plants run more safely. Waste disposal and operating safety are the two reasons for having accelerators.

Molten-salt reactors are another method of using nuclear energy to make electricity. There are no fuel rods, just a solution. People have built them, but they appear to be hard to scale up to commercial application, perhaps because of corrosion issues in the reactor vessel, or perhaps because pressurised water reactors (and BWRs) got the edge early on, so everyone now uses them as they're better understood.

Decay heat was the main problem at Fukushima, i.e. the residual heating from the decay of fission products in the fuel after the reactor has been turned off. In common with other modern reactor designs, lead coolants make use of natural convection so you don't need external power to keep the fuel from overheating. Decay heat is basically the same whatever fission technology you use, it's how it's carried away by the coolant that matters. As Fukushima has shown, it's highly desirable to have systems designed to work well without active pumping.

A couple of articles on the web say that we have Thorium targets on EMMA. We don't. The EMMA experiment is only to look at particle dynamic in rings of this type. Important, but might seem a bit esoteric. Hence the hype that the media have put in their articles to jazz things up. And it appears that repetition from article to article is diluting fact with fiction. If you want the facts, go to the source!

Hope that helps! I'm happy to follow this up if anyone has questions.

Hywel Owen
University of Manchester

Very helpful explanation, Hywel. Thank you.