Not a lot of surprises:
Yes; these people are from the bottom of their science class, like the failed electronics designers who end up being chip salesmen 
How could ITER ever generate 500MW?
They have no way to extract that amount of heat from it. It’s fundraising PR stuff.
That’s amazing
Maybe they can’t and it’s time getting on with fission, if only as a bridge. These Thorium reactors seem pretty safe to me! Let’s forget this silly definition issue that fission by definition is not renewable because it uses a resource. A very abundant resource to start with. And the waste issue is manageable.
Very true about fission. Of course we know green politics is the problem there. France has done it right. Germany? The UK may follow; I don’t understand why they have to bring in external investors. It’s like an airport allowing a franchise cafe concession instead of running a cafe themselves and pocketing all the profit.
I still think fusion research is worth doing, and my hope is that one day they will crack it, but these mega projects become primarily focal points for putting bread on the table at home for a huge number of researchers, and the Europe-based ones get bogged-down in the funding schemes which for political reasons require collaboration across teams which have no good reason to work together. In the end these things generate a large number of PhDs; most science PhDs today are awarded for collaborative projects on which the recipient did just a tiny little bit. If anyone will crack it, it will probably be done in the US.
And yes of course there will be a further loss of efficiency at the end because the theoretical limit for the steam cycle is around 50% and more like 40% with present-day turbine materials. But that will become insignificant if fusion can actually be achieved properly one day.
What is the situation with nuclear fusion waste from Uranium reactors – are even more radioactive products produced during its long life? Are we saving the planet only to doom it in the future?
Are Thorium reactors a solution?
Are our leaders aware that China is on our planet, and if we go carbon neutral it will have no effect if China supplies us using coal as an energy source?
The nearest to fusion at the moment is a project in California. IIRC ot uses 2 powerful lasers fuse 2 elements (can’t remember which ones) to produce helium, which is basically what the sun does.The helium would be used to produce heat to power steam turbines. Although probably most advanced project I think its best efforts so far is that it produces at stage 1 about 70% of rhe energy it puts into to it, and then as #Peter says a great percentage of that is lost in the steam turbines. The other problem is that to get greater efficiency and commercial amounts of electricity you will need to create a lot more heat in stage 1 of the fusion process and there are no current materials to contain that heat.
I don’t recall a fusion project using uranium but there are tens of fusion projects in labs around the world.
Fot fission you have to mine the uranium 235. Australia is one of the leading suppliers. You then have to turn that into U238 in centrifuges which is loaded into rods, usually having been pressed into pellets and the rods are bundled into canisters which are loaded into the core which contains water to both produce the steam and cool the core as needed. Every process produces waste with a half life of it is thought, a few thousand years. Because the rods aren’t changed too often, most of the waste is low level, the type of waste found in hospitals. The small amounts of high level waste can be vitrified for safe storage.
One by product of fission of this type is plutonium, which could be used in a fast reactor. But I think the countries that experimented with a fast reactor fuel cycle, the nearest so far to perpetual energy creation, like that in Dounreay in Scotland have long since closed down.
The promise of fusion, if it can ever be achieved commercially, is that there should be little or no hazardous waste and no CO2.
A little addendum is that I may be wrong about the helium part in the California project I might be merging that with the helium production in the Oxford project. But all projects are still in the lab stages for the moment.
If they can get fusion to work, there will be so much heat coming out that the 40% efficiency of the steam cycle isn’t going to be a problem IMHO the debate regarding the Q value is a redherring because currently the R&D is at such an early stage (after 50 years, yeah, I know) that it doesn’t mean anything. The laser experiments with pellets are just messing about, relativele to what any practical implementation would look like.
There have been some big recent advances in fusion in the US – last year or so I think. Much better superconductors. The problem is that if one spent billions building a vast experiment, you can’t change it just like that. It has to run for decades and churn out a lot of PhDs
What is the situation with nuclear fusion waste from Uranium reactors – are even more radioactive products produced during its long life? Are we saving the planet only to doom it in the future?
There is no technical issue with storing the waste above ground. It is “completely safe” and avoids long term questions like what happens if you encase it in glass etc and bury it in the sea or deep underground. It comes down to whether mankind is willing to accept the need for relatively secure (you can’t make an atomic bomb with it, but you could use it for contamination) storage facilities which the State has to maintain “for ever” – for thousands of years. Unless one thinks there will one day be a Mad Max situation, there is actually no problem, and if there is a Mad Max situation then we will all have bigger problems
Fot fission you have to mine the uranium 235. Australia is one of the leading suppliers. You then have to turn that into U238 in centrifuges which is loaded into rods
Gallois – I don’t think your description of uranium processing for fission plants is correct. Centrifuges are used to make weapons grade uranium, and you need some 80kg to make a bomb (plus some fairly crude engineering). I’ve just read a very detailed book on this Plutonium (a byproduct of fast breeder reactors IIRC) is a big security issue because you need just 5kg, plus some quite clever engineering, to make a bomb, and nobody can be 100% sure they can achieve the total security required, at all the power stations.
aart wrote:
Thorium reactors seem pretty safe to me!
Lots of talk (fuzz) about Thorium here some years ago (10-15 years). There are lots of thorium “ore” in Norway. The main reason development of thorium reactors stopped in the 50s/60s was that thorium cannot be used as weapons. R&D of uranium reactors yielded more “useful” stuff But AFAIK there are also some technical difficulties with thorium reactors that probably couldn’t easily be solved in the 50s, but are doable today.
I think China is the only one doing any serious thorium research today. I think they even have a reactor working, or close to it.
Excellent video by the way. It has had me fooled all these years, but probably mostly because I have not really thought about it Q_plasma, that’s just too funny. Nevertheless, it pinpoints the aim of the research. Talking about Q_tot when the basics of combustion is not even achieved, is rather irrelevant and nonsensical. It’s more the way it is communicated that is rather fishy. Hmm, even if Qplasma > 1 is achieved some day, how are you going to utilize plasma at 1 million kelvin? It will disintegrate anything it comes in contact with. Seems to me thorium yields more tangible results in the next 100 years.
@gallois, I think you’re thinking of ICF (Inertial Confinement Fusion) and specifically NIF (National Ignition Facility) at Livermore. These projects were started in the 90s as a way to do do DOE Hydrogen Bomb research while also being potentially applicable to commercial power production.
@Peter, high Tc superconductors by e.g. AMSC are an interesting development but not as revolutionary as one might imagine. When operating at a useful current density and in a significant field they still need to be pretty cold and similar pulse tube refrigerators are used for all conductivity cooled cryogenic systems – it’s no longer an issue of which liquid cryogen you need to use. I think the biggest advantage of Hi Tc conductor is that with the operating temperature being somewhat higher, the so-called ‘quench’ behavior (unintended transition to resistive conduction) is easier to manage and less destructive, as a result of higher material heat capacity (at higher temp) to soak up the energy. This then allows much more time to sense the quench and shunt the energy into an external resistive load before any damage is done to the coil.
As is often the case, the real world design is driven by fault and damage tolerance. Also true for a lot of light aircraft technology
Interesting – thanks. I read somewhere the current density is a lot higher than previous superconductors.
how are you going to utilize plasma at 1 million kelvin
You just use the radiation to heat up stuff. No contact is needed. Anything at 1M K will be radiating like hell
I guess, but one still has to contain the plasma somehow, including the radiation at 1 mill Kelvin. This is not thermal radiation as we know it (infrared light). It doesn’t heat up stuff. It’s insane intensity X-rays which which ionise atoms and break up molecular bonds.
First things first. Q_plasma, then Q_tot Even if Q plasma > 1 is achieved, the energy still has to be transformed to something that actually can be used. And this is before producing electricity through some thermal equipment.
The photons produced in the core of the sun, jump around for a billion years before they have lost most of the energy and escape as nice sun light at 5000 K.
Fusion looks to be far, far into the future
Maoraigh wrote:
Are Thorium reactors a solution?
It is somewhat beyond me, but there is a Nature paper that suggests that pure Uranium 233 can be extracted from the Thorium cycle by first refining Protactinium 233 which then decays into Uranium 233 over the next few months. This means that you might potentially refine material suitable for use in a weapon through chemical rather than isotopic separation, which is likely to be more achievable for the sort of failed state that would be delighted to possess any form of nuclear bomb and doesn’t care if it’s not quite as efficient or safe to handle as the Plutonium / Oralloy bombs that we know and love from the cold war. The revolutionary Thorium reactor designs being touted, all seem to be molten salt reactors. Similar designs with many of the same anti-meltdown safety features might also be made to work using Uranium. I think you’d have to be a nuclear physicist to truly pass judgement on their merits, but my impression is that there is a lot of hype over Thorium reactors, that may not be fully justified.
Nuclear fusion will doubtless break even pretty soon in experimental settings, but it seems that the problem of getting the energy out of the reactors is a very real one as is the issue of protecting the reactor from the neutrons it produces and building something that can continue to operate for decades. Most of the inertial confinement methods seem very fiddly and impractical to me. I rather like the General Fusion approach of compressing plasma within a big ball of molten metal, or at least I can imagine that if it does work you could make a practical device out of it relatively easily, as it would be easy to extract the heat from the metal which would also absorb much of the radiation and protect the rest of the device from it. I wish I could spread a modest investment in all of the serious fusion startups, as 1) it would be an investment in a better future and 2) the payoff, if it works, would be large enough that backing one horse out of 20 would still be profitable and 3) I have very little intuition about which firm is most likely to succeed.
I said “Fusion” when I meant “Fission”.
I read somewhere that the level of radiactivity of waste does not decline steadily as new nucleotides are formed.
