Physicist models new use for nuclear waste: Turning it into super-rare fusion fuel Tritium is ridiculously rare, incredibly expensive, and central to most fusion energy reactor designs. If research out of Los Alamos National Lab proves to hold true, it might soon become easier to obtain. Tritium is a radioactive isotope of hydrogen with two neutrons, and is typically used with the non-radioactive deuterium …
The article says that a 1GW D&T reactor would need 55kg of T, perhaps without a breeding blanket. It also says that would be enough to make 2kg of T with this new technique, even if the heat could be used for a secondary purpose. Not even close to break even. But then, that's been the story of fusion for a very long time. We need a genuine breakthrough. Until then, the best fusion plant we have is the one in the sky.
Ironic that a "clean"* fusion reactor requires a network of "dirty" fission reactors to produce its fuel.
Like you say, sunlight is free (and collecting it then storing the energy is still getting cheaper at a significant rate).
* Not actually clean because neutrons exist.
You should take a look at the various fusion cycles, which give you an approximate energy yield for each kind.
D+T has the highest energy release, followed by He3+He3 as I recall.. Forming tritium would involve D+H+e->T but is greatly outclassed by D+H->He3 and more frequently undergoing fusion with another He3, i.e. He3+He3->Be6 -> He4 + 2H for the greatest energy release in the sun's fusion process. Deuterium H+H+e -> D is more or less "energy neutral" and takes place in the sun such that the formation of D and then He3 actually adds a DELAY within the process that helps keep the sun from exploding...
https://en.wikipedia.org/wiki/Deuterium%E2%80%93tritium_fusion
https://en.wikipedia.org/wiki/Proton%E2%80%93proton_chain
It would seem reasonable to me to produce He3 as fuel directly or indirectly within the fusion reactor. One article talked about 'spin resonant' D+T fuel with a specific ratio. But forming T is apparently less frequent than He3. So why no He3 as a pure fuel??? Perhaps energy resonance, "spin resonance", and bunching techniques (velocity modulation in a traveling wave tube) could be used in accelerators to induce He3 formation
I would assume electromagnetism is the "why" in "why not"? He3 + He3 has four times the electromagnetic repulsion of D + T. Of course, D mass < He3, but the point remains: you need a lot more heat to kick things off. As little as I know about such things, this seems like a pretty strong dissuasion at this point.
> value of commercial tritium is about $15 million per pound [$33 million per kilogram]
1 GW(th) deuterium–tritium fusion plant would require more than 55 kg of tritium per year.
So $1,815 million for a year at 1GW. How much coal (oil, gas, wood) is needed for a GW-Year?
"With a coal price of $120 per metric ton and a efficiency of 42 % the fuel cost of one kwh produced by coal is 4.2 cent per kwh (electricity)."
https://www.reddit.com/r/energy/comments/1gg752o/fuel_cost_of_coal_power_plants/
8760 hours/year
$0.042*8760hr/yr = $368/KHyr
GigaWatt-Year= 10^6 KWyr
368 MegaBucks/year
Oil, gas, wood etc, also wind/water, will be similar since they compete.
NOT counting the human cost of all that coal pollution, today's tritium does not begin to compete with dumb old coal.
(Math errors likely, corrections accepted.)
Fossil fuels have, effectively, an invisible subsidy baked into them that isn't there with renewables.
Once you've hauled up a solar panel onto your roof or erected a wind turbine, exposing them to wear and tear from the very elements whose energy they are harvesting, you've already got to start thinking about getting a replacement sorted out.
But fossil fuels, you can just keep on digging up out of the ground forever*, and you never have to waste a moment of precious money-counting time thinking about replacing what you have dug up -- or, often, whatever used to be on top of it (recalls some song she heard once about a town that doesn't exist anymore because "Mr Peabody's Coal Trains have hauled it away").
* Until they run out, anyway ..... But the people making money hand over fist really don't care about any of that.
Indeed. One way to produce Tritium that sounds feasible at the cocktail napkin stage is to bombard natural Lithium with slow Neutrons. Some of the small percentage of Lithium-6 (between 2 and 8%) will fission into an atom of Helium-4 and one of Tritium. The reaction is exothermic BTW. But the heat may be more of a nuisance than a useful power source.
D-T fusion comes with two major drawbacks. The limited availability of T has already been discussed. The second problem is the release of neutrons. Neutron radiation is both incredibly difficult to shield and incredibly harmful.
Both these drawbacks are addressed adequately by the use of a 6Li breeder blanket. A small amount of T is needed to start the reaction, at which point the neutron radiation is absorbed by the 6Li to produce T (and 4He, which is essentially irrelevant in this context). This solves both the neutron radiation problem and the T requirement problem at once.
Even if spent nuclear fuel could be reworked profitably to produce T, it still wouldn't have the advantages of using 6Li as a T breeder.
Also, reworking spent fuel into 6Li seems impractical given the abundance of natural Li.
Did someone get a fusion reactor to work while I wasn't looking?
Producing a sustained energy surplus one might notice without expensive technical timing equipment that can measure gnat-fart times?
Because all this seems a bit, well, moot unless we actually have a working fusion reactor design.
Fusion reactors have got to the point where they can generate energy for around five seconds, which isn't long, but I'd say it qualifies as longer than a gnat-fart*.
*Unfortunately elReg's unit standards don't include a way of measuring time smaller than the 'Truss', and no fusion reactor has managed to run that long.
