Including thorium, it ranges from 17,000 to 250,000 years at 1999 electricity production levels, depending on whether you mine unconventional sources like seawater. So we should have at least ~ 1,000 years before ITER is necessary even if electric demand keeps increasing and only nuclear fuel is available.
n*kBolt*Te = B**2/(2*mu0) and B^.25 loss scaling? Or not so much? Hopefully we'll know soon...
2. Mass power density has to do with the mass of the structure, not the fuel. The cost of electricity is based on how much stuff it takes to produce a given amount of power. There are two primary drivers for the COE: the mass power density and recirculated power fraction. My point is that if ITER-like machines are going to have the same cost as an LWR, they have to reduce their size by factors of a few hundred. The most advanced Aries designs reduce the size by a factor of 10. What the Polywell does is that it eliminates the blanket and sharply reduces the shielding, increasing the mass power density and leading to an attractive device. P-B11 allows you to do this. That's why the Polywell has a customer while the Tokamak doesn't, and hasn't had one for at least 25 years.
Light water reactors are at best marginally competitive (the financing requires a federal subsidy) so if you can't compete with them you are going to have a hard time competing with anyone. Fusion people seem to have the attitude that the only choices people will have is fusion power or freezing in the dark, therefore fusion doesn't have to be competitive. I don't agree with that. Furthermore, solar and wind are going to have a 50 year headstart on tokamak fusion and that Tokamak is going to have to be extremely attractive to overcome all of that inertia.
Apollo didn't have to produce an economically attractive product. The cost and length of the development path for Tokamak fusion is extremely important and totally ignored. When I talk to private investors I get asked the following questions (in order of importance)
1. Does it make an attractive product?
2. How long is the development path and how much will it cost?
3. Do you own the intellectual property?
4. Will it work?
The tokamak doesn't make it past question 1. That's why there is no interest in tokamaks outside of the fusion researchers. Noone cares if ITER works.
From RNebel ..."That's why the Polywell has a customer while the Tokamak doesn't, and hasn't had one for at least 25 years."...
Reading between the lines- does this mean that EMC2 has funding for further development, possibly from a venture capitalist source Or, does it just refer to the past Navy contracts?
TallDave wrote:Including thorium, it ranges from 17,000 to 250,000 years at 1999 electricity production levels, depending on whether you mine unconventional sources like seawater.
Just so people who don't read the article are aware, note 'iv' on page 13 says that they only include nuclear produced electricity from 1999, which was around 15% total world energy (electrical) usage. Actually 6% of energy (all sources) use. Fairly insignificant on the scale of things.
Assuming we do away with fossil fuels (or they magically run out overnight like some people think they're going to do) nuclear would obviously have to compensate. Uranium could only be viable for any significant period of time in fast breeder reactors, in that scenario, imho. Making more assumptions like the further industrialization of the developing world and such. I just found it annoying that they fiddled their number the way they did.
ITER is otherwise superior to LWR with respect to long term reserve viablity and political access to reserves. The argument for D-T remains a good long term goal.
But I'm not disputing the short term profitablity of LWRs over ITER. ITER is a darn beast. LWR is a joke. Heh, ITER makes LWR look like a homemade engine I could make in my backyard...
rnebel wrote:That's why the Polywell has a customer while the Tokamak doesn't, and hasn't had one for at least 25 years.
Not trying to read too deeply into this statement, but it sounds like (at least as of yesterday) the Navy is still on board. To what capacity is anyone's guess.
rnebel wrote:That's why the Polywell has a customer while the Tokamak doesn't, and hasn't had one for at least 25 years.
Not trying to read too deeply into this statement, but it sounds like (at least as of yesterday) the Navy is still on board. To what capacity is anyone's guess.
Yes, it seems so. I think thats why the insight into Plant Mass : Power ratio being so important. Maritime use.
Now if we could only get the navy to sponsor a prize, backed by the US Taxpayer, outside the Navy budgets whereby the navy gets free use of all patents. The prize would be for a 100MW pB11 device, suitable for a destroyer in terms of the machine Mass : Power ratio, where the payout would be a cool, tax free $1Billion. Foreign winners welcome, everyone can play. Such a device would be worth much more than $1Billion to the Navy alone. Lets see some Venture Capital start to move on this.
That link Talldave posted about U-235 reserves was very interesting. While I don't endorse assuming we'll find more U-235 rich seams as a sound energy policy should not be based on wishful thinking. I was impressed by that exponetial curve of purity versus quantity. It seems that if we are willing to sacrifice a factor of 100-1000 in purity we would gain a factor of 100 in quantity. I think I agree with the statement that $135/kg is too low and upper limit to place on economically recoverable reserves. And ofcourse with breeder reactors not only would the Uranium available be used ~100 times more efficiently, but because of this increase in efficiency, this would make ore that was 100 times less pure economical to mine, as the energy value would be raised by a 100. I see what they mean by "practically limitless".
I think the bottom line is if you aren't worried about waste and proliferation, nuclear fission is always going to be cheaper than fusion (let's face it, p-B fusion with a polywell is long shot in the extreme, though still an approach worth investigating). Sub-critical fusion-fission hybrids might concievably be a safer way to breed fissile fuel from fertile fuel with a factor of 30 improvement of the power/mass ratio of the device. In addition the D-T and He3-D reactions produce ~17MeV, which is 3MeV per nucleon compared with 1Mev/ nucleon for fission, this may concievably give it the edge in futurististic space propulsion applications as the thrust to mass ratio is higher (I believe p-B gives 0.66 MeV/nucleon). In addition fusion devices could make energy neutral high density sources of 14MeV neutrons for research (although I have no idea what the demand for such neutron sources are, quite possible in the case of a GW source, very low indeed).
If you are very worried about waste, CO2 emissions, security of energy supply and weapons proliferation then being economically competitive against fission power is no longer required. What you must now do is simply produce considerably more energy durng the lifetime of the power station than was used to construct and operate it. Tokamaks may well be capable of achieving this requirement, though it is still uncertain.
Perhaps we do make too much fuss over nuclear waste. France supplies 80% of its electricty from nuclear power and the French aren't 4 headed mutants, they even have a comparably high life expectancy by European standards. If waste an proliferation truly are manageable issues. Then the greens have succeeded in royally frick up Europes energy policy with the result of us having to import 50% of it at great expense from other countries. Perhaps the green movement lack of support for nuclear power could be in part responsible for the current crisis of global warming.
And how do you answer #4?
Or, does it just refer to the past Navy contracts?