[mjv1121]

Tokamaks (ITER) is not a gamble of any sort, it is a fools errand, a total and utter waste of money and resources, a blind alley, a dead end. The entire concept is nonsense, attempting to use magnetic fields to confine fusion energised plasma is somewhere between madness and stupidity.

The science is entirely unproven and unjustified, and the engineering is impossible.

[mjv1121]

what I meant to say/type was “not entirely clear”. I hope that’s clear. If its unclear or if you’re not clear about what I meant to say, then don’t hesitate to ask for clarification.

[mjv1121]

zapkitty has, perhaps unwittingly, made an very good point – The easiest way to improving cooling would be to decrease output.

Take a 1MW device – that is 1000 FoFu’s per GW. Eric was hoping that these things could be mass produced for $300,000. So let’s guesstimate an average install cost of $500,000 per MW – that’s $500,000,000 per GW.
Coal and Natural Gas are struggling to hit $2,000,000,000 per GW installed. Add to that the cost advantage to grid systems – placing generator’s near the load – FoFu’s could put a serious dent in the pylon industry – would be especially in emerging markets.

Of course there’s still merit in having 5MW generators or 6, 7 or even 10MW if it can be done – I’m just saying that a 2 or 3MW device is far from being a failure. A 2MW generator (including a reduction on transmission costs) would represent a saving of 8 to 10 times less than all other options currently available – a 5MW generator, 20+ times cheaper than any other option currently available.

redsnapper

The proportion of energy released from each beam is dependent of several variables – fuel gas pressure, magnetic field strength, quantum mechanical effects – shit like that. Also the size of the electrodes plays a big role. The basic idea at this stage is to get the plasmoid as dense as possible to create conditions for pB11 fusion. Until they get past the experimental stage its entirely clear exactly what size the electrodes will be and consequently the “combustion” chamber and how much and in what proportions the energy will be released and recovered. Seeing as no one has put forward any objection to my numbers they’re probably as good as any right now.

[mjv1121]

Hello redsnapper,
I don’t think you’ve quite understood where the “heat” is.

The capacitor bank puts electrical energy in – 100% in, lets call it 100x in
The plasmoid thru various atomic and plasma processes converts generates extra energy from the fuel and the amount of energy increases to 180x (perhaps over 200x).
The plasmoid releases this energy in 2 main ways:
1) The ion beam away from the electrodes, this is going to be quite focused. Because the beam is charged particles in motion, it is effectively already electricity. Using a special induction coil transformer thingy the ion beam will be converted into “usable” electricity. Hopefully this can be done at 80% efficiency. So the ion beam removes an energy of 90x from the plasmoid and gives us 72x in electricity and 18x in waste heat.
2) The other side of the plasmoid produces an electron beam. These electrons lose most of their energy by emitting x-rays. The x-rays are then converted directly to electricity by the “photo-electric onion” thingy. So the electron beam removes an energy of 90x from the plasmoid via x-rays and gives us 72x in electricity and 18x in waste heat.

So we have 144x in electricity and 36x in waste heat. The 144x electric will be split 100x back into the capacitor bank for the next pulse and 44x electric. The stated target was to generate 5MW electric, so the 44x equates to 5MW. So the 36x equates to about 4MW – of course thermal and electric are not quite the same thing, but the ion beam and x-rays are not “heat” either. This is the main advantage – fusion is almost a smokescreen to the real beauty of the device, and that is, generating electricity without using a thermal system.

So there’s going to be 2MW of megawatts of heat in the ion beam transformer and another 2MW in the x-ray onion. Although most of the energy from the plasmoid is removed by the ion beam and the electron x-rays there’s going to be losses and possibly side reactions, enough to heat the central electrode to 1000K. Some heat is needed to maintain the fuel as a gas, but the big problem is keeping the electrode cool. Unfortunately I haven’t been able to glean any detail on thermal heat numbers other than its going to be made of beryllium, approximately 25mm in diameter and 150mm long and will be at about 700C.

My thoughts with the thermo-electrics was to try to raise the overall efficiency of the machine with an additional direct-to-electricity method. With a total “waste” of about 5MW, it seemed like a good idea to try to re-coup say 500kW. It would ease the pressure on the ion beam transformer and x-ray onion design teams or reduce the pulse rate and prolong the wear-and-tear.

[mjv1121]

You say above that China has “initiated a research and development project in Thorium…” That tends to mean that it doesn’t actually work yet.
– ORNL had a liquid fluoride reactor working for 5 years in the 60’s, and they demonstrated that it can burn all three fissile materials: uranium 233, uranium 235 and plutonium 239 – the R&D is really to do with choosing the right materials and design to use as a long term, reliable, “commercial” energy generator.

How does their R&D schedule and issues compare to the Bill Gates proposal noted in the TED talk?
– Molten Salt Reactor technology is way more developed than travelling wave reactors. In fact if you wiki TWR’s you’ll see that the concept of a “burning log of uranium” that you “fill-up and leave to burn” has already been abandoned.

Bill also enthused about the way Terrapower uses spent uranium and turns a problem into a solution, but then asks “Why haven’t we heard of this before” and answers himself with: Innovation really stopped in this industry quite some time ago. The idea that there are some good ideas laying around is not all that surprising.
– If you’ve ever heard the term “fast breeder reactor”, then you have heard of this before. In order to use uranium 238 as fuel you need to convert it into plutonium 239. To do this efficiently you need a fast spectrum reactor, ie fast/high-energy neutrons. So you are breeding plutonium 239 (which fissions (splits) and releases energy) from uranium 238 which does not fission. In a LFTR you breed uranium 233 (which fissions) from thorium 232 which does not. Uranium 233 fissions very efficiently in a thermal spectrum (read slow/low-energy neutrons) reactor. A more likely candidate for a fast breeder is IFR, which had received a lot of research in the US until the 90’s.

Part of the problem with fast reactors and also with today’s light water reactors is the amount of fissile material needed to start them up, which is 4-5 times more than you need to start a MSR. Also thorium is 3-4 times more abundant than uranium. Assuming you had the will and the capital to build more LWRs and fast reactors, you will still be limited by the amount of plutonium or enriched uranium available to get them started.

“If things go well.” Is there a similar uncertainty factor with the MSR’s?
– China have spoken about a 20year program. Personally, I’d be surprised if they don’t have prototypes working in 5 years and starting deployment in the second decade of the program.

Bill seems to think that there is enough uncertainty in fission all around to warrant HUNDREDS of similar R&D projects launched. Perhaps Thorium MSR was one such. He says:
There are, fortunately now, dozens of companies, we need it to be hundreds, who likewise, if their science goes well, if the funding for their pilot plants goes well, that they can compete for this. And it’s best if multiples succeed, because then you could use a mix of these things. We certainly need one to succeed.

So, again, is Bill foolishly overlooking the already functional thorium reactor? Can he just drop the terrapower and go snap up a Thorium reactor today? I feel some information is missing here.
– He speaks in passing of problems with liquid reactors so I don’t know what he is referring to. As far as TWR’s are concerned, I suspect he has been seduced by the “light and leave it” scenario and by the prospect of using depleted uranium as fuel.

There are two parts to the waste from LWR’s. One is the spent fuel from reactors and the other is the depleted uranium leftover from enrichment. Depleted uranium is not a worry as such, since it is “depleted”, ie it is less radioactive than when it was originally dug up. The difficulty with spent fuel is that it is in a form that is very difficult and expensive to work with and this is fundamental to the inefficiency, expense and large waste stream from solid fuel reactors.

…..more to follow

[mjv1121]

The numbers don’t really seem to add up. And what if you don’t have a mains gas supply? Could well be a similar story to wind and solar – starts off sounding great, but when you look at more closely…..it ain’t!

[mjv1121]

Whether in a car, power station or some other industrial process, a few percent of waste heat recovered could make a significant difference to the efficiency of the system overall – dependent on cost and complexity – clearly TE devices have the potential to provide this in some applications.
Another perspective to take with regard to Fo-Fu is robustness and reliability. Any improvements in energy recovery may give the option to run at a lower frequency. Less pulses per second should result in improved reliability and a longer maintenance schedule – think third world – sorry, I mean “developing countries” or is that “emerging markets”. There’s also marine and eventually space applications where design priorities will likely differ.

I originally considered the subject of heat recovery due to “net energy paranoia”, hopefully the numbers will be quite sufficient. but its always nice to have options.

[mjv1121]

Is my grasp of expected efficiency more or less accurate then (see the top half of my first post)

[mjv1121]

More TE automotive food for thought – here’s a slide presentation entitled “Advanced Thermoelectric Energy Recovery Systems in Future Vehicle Systems” by the U.S. Department of Energy’s National Renewable Energy Laboratory :
http://www.nrel.gov/vehiclesandfuels/ahhps/pdfs/epri_hendricks.pdf

[mjv1121]

Both GM and Ford and probably others are looking to wrap the exhaust in thermoelectric (TE) material in the hope of increasing vehicle efficiency by a few percent, perhaps 5% or so – this becomes particularly relevant for hybrids. One must presume that the cost of such a system would not be too high relative to the cost of the vehicle. Of course adaptation of such a technology may not be suitable or possible, but is it not certain that cost will be a barrier. As I said before, if there is an over abundance of net energy then no worries, but it does no harm to consider backup plans. Also, in 4-5 years time when hopefully a Focus Fusion prototype is well under-way it is not inconceivable that may be fairly common place in the automotive industry – I’ll dust dust off my crystal plasma ball and see what the future holds……… yes I can see it now – lots and lots of plasma!

[mjv1121]

Some more facts and numbers to cheer or weep over:

It seems that the biggest problem China has with coal, is transportation – the conventional rail system is working at capacity, so most of the coal is delivered by truck, leading to horrendous traffic problems.
Apparently, China already has plenty of thorium stock piled – a “by-product” of rare-earth mining – currently they have no use for the thorium.

“Hey, I’ve got a good idea. Why don’t we use the thorium to make electricity – its much easier, much safer and much cheaper than present nuclear and we can get that damn coal out of our transportation system.”

but what about the cost?

It looks like ITER will cost the best part of of $20 billion, which is quite a lot. Experiments are due to start in 2019.

China is spending $300 billion by 2020 on its electricity powered high speed train network.

I think its safe to say that the thorium reactor project will be sufficiently funded.

[mjv1121]

if you start following solution space paths thru differential equations you’re almost certain to get lost, even if you’re on a pretend Scottish bicycle

[mjv1121]

First of all, to state the obvious, I believe the most important thing is to move to an all electric society (which may or may not include hydrogen – incidentally LFTR would be great for process heat to extract hydrogen). In order to achieve that there we need a method of generating electricity that is considerably more viable than burning fossil fuels, both economically and environmentally. Thorium powered fission could certainly be economical and would be orders of magnitude greener than wind and solar.
The problem with the present fission technology is the fundamental inefficiency of solid fuel and the subsequent considerable waste stream. Bill Gates is an advocate/investor in Travelling Wave Reactors – basically a variation on-a-theme of solid fuelled sodium cooled fast reactors like IFR. The big – very big – advantage with molten salt reactors is that they use liquid fuel – molten salt in fact . This turns a nuclear reactor from being a dangerous beast that must be controlled using “defence in depth”, into a reactor that is self-controlling and can be chemically processed. In addition thorium is far more abundant than uranium, certainly sustainable for a few hundred thousand years. All in all, a thorium powered world would be very very acceptable.

The reason that D-T fusion will find it hard to compete is that there is no advantage – LFTR really is that good. A “pleasant physics surprise” card could be Aneutronic fusion, but even that is not much of an advantage against LFTR. What we need is a small, but scalable generator, that can be manufactured and implemented at a 90-95% cost saving…..focus fusion! I do think the fact that its the Chinese that have made this move could (maybe, possibly) be an advantage. It may motivate the powers that be to take a second look at alternatives. The problem remains though, that its not the decision makers that are the stumbling block, its the advisors to the decision makers.

As a point of interest (and because I’m a MSR nerd), the molten salt is the same salt that is proposed to be used for cooling and heat transfer for tokamaks and LIFE. For fusion use it has the added benefit of making tritium, which is quite useful cos it doesn’t grow in the wild.

[mjv1121]

Clearly there is a difference of opinion, even within plasma physics community, and I must concede that the consensus view is to accept that reconnection is a genuine process. I choose to believe that it is a misinterpretation of current effects in plasma. I don’t think either of us is likely to convince the other, so shall we agree to differ, or shall we stamp our feet and shout louder?

[mjv1121]

“There is no ‘field-line reconnection’ that can transfer energy to the particles, nor release energy in any other way.” – Hannes Alfven 1976

…I have found an excellent page: http://sites.google.com/site/cosmologyquest/what-we-do-know/magnetic-reconnection

However, back to crossfire. My point was that if he mentions magnetic reconnection (which does not exist) raises a certain doubt.
Mind you, it would be fantastic as spacecraft propulsion if it worked. I still favour Focus Fusion for terrestrial power generation – its mechanical simplicity and small size are an enormous advantage.

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