Where is deuterium and tritium found?

[Xian]

How is it isolated for nuclear fusion?

 

 

[swansont]

http://en.wikipedia.org/wiki/Deuterium#Production

 

http://www.nuclearfaq.ca/cnf_sectionD.htm#x5

[mathematic]

Deuterium occurs naturally in water. Tritium has to be made.

[Enthalpy]

Tritium is too scarce in Nature to feed fusion reactors. It must be produced, and this problem for full-scale production of electricity by fusion reactors is not solved.

 

Presently, the demand is small, for experimental fusion reactors and for nuclear bombs of "boosted" design, that is, nearly all bombs. The uranium reactors provide it, part at Candu reactors, part at normal water reactors where it is a minor product of normal operation, and could be obtained in bigger amount by introducing lithium.

 

This path wouldn't be viable to get much electricity from fusion reactors, as it takes many big uranium reactors to supply one small fusion reactor, cancelling its usefulness.

 

Alas, all methods to obtain significant amounts take big flux of neutrons, which means a nuclear reactor, so the developers of ITER have realized that the reactor must regenerate the tritium it consumes, using tritium breeding blankets

https://www.iter.org/mach/tritiumbreeding

http://www-fusion-magnetique.cea.fr/gb/cea/next/couvertures/blk.htm

 

One D-T fusion provides one neutron, and one neutron absorbed by lithium makes only one T, too little to compensate the losses, so the answer by ITER's proponents is to multiply the neutrons: the 14MeV fusion neutron is to hit a lead nucleus which emits more neutrons, and these are captured by lithium.

 

Problems:

 

Whether such a blanket can really breed as much tritium as the reactor consumes is doubtful. No better multiplier seems to exist (except ²³⁵U and ²³⁹Pu...), as beryllium is too scarce. ³He could be a better target than Li but it's badly scarce on Earth, and mining the Moon for it is really a bizarre idea: it's very scarce there as well, the technology doesn't exist, and, well, the alternative is just wind turbines on Earth.

 

Neutron multiplication by lead is dirty. Very dirty: about as much as uranium fission for the same electricity. My estimates are there

http://saposjoint.net/Forum/viewtopic.php?f=66&t=2450

 

I had invited Poitevin, the designer of ITER's demonstration blankets, to answer my arguments, but he didn't, so we ignore if he has some. The main change is that the documentation about neutron-lead reactions has disappeared from the Web. Copies exist, fortunately.

 

To my understanding, this problem is fundamental. Not just a matter of technology for which we could hope progress; it's as dumb as counting neutrons. Presently, I suppose no solution exists, and without a solution, nuclear fusion is useless. Why invest tens of G€ in a technology known to be polluting in case it works in many decades, while we have renewables at hand right now and cheap? The brilliant people working on fusion would better develop good methods to store electricity at the grid scale, we need that.

 

It's a huge disappointment, sure. Other methods of fusion aren't better off: laser fusion doesn't target anything else than D-T since all others are much more difficult; magnetized target fusion has the same difficulties as the others; maybe perhaps the Z-striction could consume other fuels, but that's very hypothetical, and production of electricity is not the main goal of this machine; people there have let known recently that a net energy gain would take a machine some 4 magnitudes bigger than their big thing.

[Enthalpy]

When the construction of ITER began, the cost estimate had already swollen to 14G€ - a lot in absolute terms - and presently it seems to be around 36G€, while the project is only at its beginning.

 

At that price, it is perfectly normal that governments and parliaments check if the investment brings us somewhere. Unfortunately, I haven't seen any sort of answer to the problem of pollution by the neutron multiplicators. While ITER is a demonstrator which doesn't have to answer every detail of a working production reactor, I feel this is a fundamental problem with a very serious potential to make the whole attempt useless, so having no answer worries me.

 

For far less money, we would know how to store electricity, and then wind turbines make already cheaper electricity than uranium reactors.

[John Cuthber]

It's a huge disappointment, sure. Other methods of fusion aren't better off:

Best switch the sun off then.

[Blake Burns]

Tritium is too scarce in Nature to feed fusion reactors. It must be produced, and this problem for full-scale production of electricity by fusion reactors is not solved.

 

Not all forms of fusion currently under study require tritium-I've been reading up on the process being studied by Helion energy, a variant of magneto-inertial fusion production that uses deuterium and helium-3 through the following reaction:

 

2D+3He→ 4He+ 1p+ 18.3 MeV

 

The massive advantage of this is, the reaction naturally generates more of the scarcer kind of fuel through the fusion process, which as you might expect is very handy, since it means that with every fusion reactor built,they will have more of it available to help start up new ones. It's also very low on neutron production, and the neutrons it does produce are very low energy.

 

That being said, if your concerns about fusion reactors not being able to make enough tritium during the process itself are indeed accurate, couldn't we simply have a tritium production facility to provide the fusion reactors with this substance separately from their operation, perhaps using large drums of lithium periodically exposed to neutrons and then processed to extract the tritium? Even a few hundred tons of it being produced a year would be enough to provide fuel for pretty much all of humanity.

[imatfaal]

Not all forms of fusion currently under study require tritium-I've been reading up on the process being studied by Helion energy, a variant of magneto-inertial fusion production that uses deuterium and helium-3 through the following reaction:

 

2D+3He→ 4He+ 1p+ 18.3 MeV

 

Don't understand your equation.

There is no helium-3 in it - unless you and Wiki and every site promoting this technology all dont use/ understand Superscript

 

²D+³He→ ⁴He+ ¹p+ 18.3 MeV

 

Now that's better - but you are gonna have to have serious heat and pressure to over come coulomb barrier (you have twice the charge) and surely the Deuterium under that heat and pressure will react in a D-D fusion and give off an energetic neutron of 3.3 mega-electron volts (which you cannot easily control using your magnetic field) which is not all that low an energy contra your assertion. I must admit I would have thought D-D would have dominated the fusion reaction.

[Sensei]

What is worser is that when we have high kinetic energy particle that will hit Deuterium:

 

[math]_1^2H + 2.22 MeV \rightarrow p^+ + n^0[/math]

 

Free neutrons will be created.

[John Cuthber]

 

On 11/30/2014 at 8:49 PM, Enthalpy said:

Tritium is too scarce in Nature to feed fusion reactors. It must be produced, and this problem for full-scale production of electricity by fusion reactors is not solved.

Is now.

 

3 hours ago, Enthalpy said:

D-D reacts too but produces little heat as it releases the less stable ³He or T

DD reactors exist.
I'm thinking of making myself one as a toy.

https://en.wikipedia.org/wiki/Fusor

[Duda Jarek]

I have seen some papers that tritium is also found in volcanoes, suggest ongoing nuclear reactions (half-life ~12 years to to He3)

https://www.sciencedirect.com/science/article/abs/pii/S0377027399001778

Quote

(...)we analyzed samples from 11 active volcanoes ranging in composition from tholeiitic basalt to rhyolite: Mount St. Helens (USA), Kilauea (USA), Pacaya (Guatemala), Galeras (Colombia), Satsuma Iwo-Jima (Japan), Sierra Negra and Alcedo (Ecuador), Vulcano (Italy), Parı́cutin (Mexico), Kudryavy (Russia), and White Island (New Zealand). Tritium at relatively low levels (0.1–5 T.U.) is found in most emissions from high-temperature volcanic fumaroles sampled(...)

It brings interesting question of He3/He4 ratio in Earth mantle, e.g. http://www.mantleplumes.org/HeliumFundamentals.html

Generally there is problem with He3 sources required for many application like ultra-cooling or lung imaging, especially after 911 as a lot of it was needed for neutron detectors for airport security. I have heard that its important source was decay of tritium in thermonuclear warheads and in some moment Russia has stopped selling ...