Why ITER is a Useless Investment: The Truth about Tritium and Tokamaks

[Mech_Engineer]

The NIF LIFE concept proposes to create it's own Tritium using a Lithium-enriched liquid salt blanket:

Q: Tritium is rare and very expensive to produce. How would a fusion power plant get the tritium it needs to sustain continuous fusion reactions?

A: It's true that tritium exists only in small quantities in nature, so a fusion energy power plant would need to create its own tritium fuel. The neutrons generated in the fusion reaction will be absorbed within a liquid salt blanket surrounding the fusion chamber to create a hot fluid that will turn a turbine to generate electricity. The salt will contain lithium, which will react with the fusion neutrons to produce helium and tritium. Due to neutron multiplication reactions, it is possible to make more than one triton (tritium nucleus) for each one consumed in fusion reactions, creating a net positive generation of tritium. This tritium is then sent to the target factory to be used to produce new targets.

https://lasers.llnl.gov/education/faqs.php#tritium

 

[Drakkith]

So Enthalpy, you don't agree that funding the ITER, which could possibly lead to fusion using not only D-T, but also D-D or other fuels, is a worth it?

 

[Joseph Chikva]

So Enthalpy, you don't agree that funding the ITER, which could possibly lead to fusion using not only D-T, but also D-D or other fuels, is a worth it?

He is right saying:

Other reactions than D-T would solve that but are out of reach by tokamaks, even on the timescale of fusion research.

 

[Joseph Chikva]

Yes, that's the point. Actually, until I read the OP's post, I never realized how critical this blanket was. It will be quite difficult to achieve self-sufficiency, because of course you cannot capture the neutrons in 4 pi without any structural capture and loss. So you need a neutron multiplier.

D-T reaction needs neutron multiplying coefficient 1.15-1.25 or to produce Tritium in existing fission reactors. And no any other way.

Non-fission neutron multiplication isn't easy (apart from spallation). If it were, people would use it to make thermal breeders with uranium

That’s not so. If considering that realization of fusion means less danger wastes.

Yes, of course, but when you look at the difficulties people have to realize self-sustained, energetically useful let alone commercially competitive energy from D + T (that's the hope in the second half of this century) even granted tritium provision, D + D is for the 22nd century at best.

I doubt in commercial feasibility of D-D reaction. More interesting is to build D-T reactors with bigger than 1.15-1.25 Tritium breeding coefficient, then to wait till some tritium will decay to He3 and then to build aneutronic D-He3 reactors.

I'm not saying ITER is useless, but the tritium bottleneck is yet another difficulty as compared to the rosey pictures of "soon, clean energy here", no ?

ITER useful for accumulation of technology know how – magnets, vacuum, blanket, first wall, neutral injection, etc. Someone should do these jobs.
But I doubt that TOKAMAK as such ever will be able to generate net power. As if you see this link: http://iter.rma.ac.be/Stufftodownload/Texts/BurnCriteria.pdf where is taken into account real energy conversion cycles’ efficiency is calculated that required confinement time should have an order of 560 s. (page 8 after formula (57) ).
But there is not any bottleneck with Tritium. And I am disagreeing with statement mentioned here as Lithium is a rare element.

 

[Enthalpy]

More interesting is to build D-T reactors with bigger than 1.15-1.25 Tritium breeding coefficient, then to wait till some tritium will decay to He3 and then to build aneutronic D-He3 reactors.

While Lithium is certainly abundant enough, reaching the mandatory Tritium breeding coefficient looks impossible, given that present computations don't integrate many difficult constraints.

Any designer likes to start with a margin of 10 at scratch, if he's to keep >1 as his design advances. For uranium chain reaction, they had 2.4 neutrons to keep 1 and this needed a big effort to develop materials, forms... Starting from 1.15 is disheartening - to my eyes it's impossible.

³He-D is even more difficult than D-D because of the third repelling proton.

Then, you have the radioactive pollution by the regeneration blankets, which promises to be as bad as uranium fission.

Developing Tokamaks for the sake of pure science may be fun, but not if we need energy right now, not if we see a probable impossibility, not if it takes for decades thousands of brilliant people who could solve instead more productive challenges, like electricity storage.

 

[Joseph Chikva]

While Lithium is certainly abundant enough, reaching the mandatory Tritium breeding coefficient looks impossible, given that present computations don't integrate many difficult constraints.

Any designer likes to start with a margin of 10 at scratch, if he's to keep >1 as his design advances. For uranium chain reaction, they had 2.4 neutrons to keep 1 and this needed a big effort to develop materials, forms... Starting from 1.15 is disheartening - to my eyes it's impossible.

³He-D is even more difficult than D-D because of the third repelling proton.

Then, you have the radioactive pollution by the regeneration blankets, which promises to be as bad as uranium fission.

Developing Tokamaks for the sake of pure science may be fun, but not if we need energy right now, not if we see a probable impossibility, not if it takes for decades thousands of brilliant people who could solve instead more productive challenges, like electricity storage.

To my eyes it's impossible to produce net power using TOKAMAKs and D-T reaction.
But I am talking not about the viability of certain fusion Method. But here I am only talk about fuel cycles. And tritium breeding with any needed breeding coefficient is less complicated challenge than the breakeven achievement.
I never heard about blankets in which a few years loading of breading materials (Li6+neutrons multiplier) should be placed. But only current quantities. So, that will not be as dangerous as fission in case of accident.

not if it takes for decades thousands of brilliant people who could solve instead more productive challenges, like electricity storage.

You are wrong. Demand on electricity growths. And only growth of generation would solve a problem. Or we would not need any electricity storage.

 

[mheslep]

You are wrong. Demand on electricity growths. ...

Not lately in the US:

http://www.eia.gov/totalenergy/data/annual/txt/ptb0802a.html"
2005 4,055
2006 4,064
2007 4,156
2008 4,119
2009 3,953
2010 4,120

Similarly US energy intensity, that is energy per $ of economic production has been and continues to decline.
http://www.eia.gov/emeu/25opec/sld022.htm

 

[Joseph Chikva]

Not lately in the US:

http://www.eia.gov/totalenergy/data/annual/txt/ptb0802a.html"
2005 4,055
2006 4,064
2007 4,156
2008 4,119
2009 3,953
2010 4,120

Similarly US energy intensity, that is energy per $ of economic production has been and continues to decline.
http://www.eia.gov/emeu/25opec/sld022.htm

World production? China, India, Brazil, some developing countries? Total energy generation?
That is not engineering but more an economical and political issue.
If cheap electricity in US would increase the competitivnes of US economics and generation demand will growth as well. Certainly if USA is not going to concede its economical leadership. The gap between China and USA is smaller and smaller.
And renewables are not cheap.

 

[Drakkith]

Not lately in the US:

Umm, I don't think that looking 5 years in the past is sufficient to say that future energy demand won't/isn't increasing. A quick look on that table shows that up until 2008 there was a continual increase. And if your view of "lately" is only 3 years ago, then I think you should expand your view on the situation.

 

[westfield]

Any chance you can confine the fusion bashing to ONE thread encephalaphy?

 

[mheslep]

Umm, I don't think that looking 5 years in the past is sufficient to say that future energy demand won't/isn't increasing.

"Won't" and "Isn't" are to very different things. I did not say "Won't". The data says, not me, that for the last 5 years US electric demand "Isn't" increasing (linear fit).

A quick look on that table shows that up until 2008 there was a continual increase. ...

The 5 year window is sufficient to say this: the 5 year trend (ie lately) is flat or down with a linear fit to those numbers, no more no less.
US billion kwh vs year:

 

[Joseph Chikva]

• Till 2008 increasing.
• After August 2008 (crisis beginning) some fall which if we call as” trend" - very short term
• After the end of crisis - do not know but think that growth again

 

[Drakkith]

Let me put it this way mheslep. Your post was pointless and serves no purpose in regards to this thread. Not only did it not refute what you quoted, it ignores all long term trends, other variables, and only takes one single country into account. So what if the US energy usage has flattened out in the last few years? That has no bearing on this discussion.

 

[mheslep]

Let me put it this way mheslep. Your post was pointless and serves no purpose in regards to this thread. Not only did it not refute what you quoted, it ignores all long term trends, other variables, and only takes one single country into account. So what if the US energy usage has flattened out in the last few years? That has no bearing on this discussion.

Ah, good, then the US can drop all support for ITER.

 

[Enthalpy]

Poitevin's description of tritium-breeding blankets has moved, available here:
http://www.iter-industry.ch/wp-content/uploads/2010/01/Pr__sentation_Poitevin.pdf

 

[Enthalpy]

Poitevin's Pdf tells that beryllium could be an other neutron multiplier, as an alternative to lead, but beryllium is scarce.

Believing the miners at USGS rather than the chemist cited by Wiki, we have 80,000 t of beryllium ressources - exploitable ore, not reserves which limit to present economic conditions.
http://minerals.usgs.gov/minerals/pubs/commodity/beryllium/mcs-2012-beryl.pdf page 29

According to the IEA, the worldwide energy consumption was in 2008:
http://www.iea.org/textbase/nppdf/free/2011/key_world_energy_stats.pdf (pages 24 and 6)
- 15 PWh = 54 EJ as electricity made from hydrocarbons (including coal) or from uranium;
- 10 Gtep as hydrocarbons (including coal) or uranium, or 440 EJ replaceable by 300 EJe of electricity.

1 mole or 9g of beryllium produces about 1,4 mole of tritium of which each atom produces 25MeV heat converted to 35% in electricity, or 130 TJe/kg of Be.

If other uses continue to need 270 t/year of beryllium, ressources cover :
- 120 years of electricity, needing 270 + 410 t/year. That's less than coal;
- 31 years of hydrocarbon replacement, needing 270 + 2300 t/year - and we want to replace hydrocarbons.

With beryllium as a neutron multiplier, ITER wouldn't hold it promises. Even if it only produced the electricity presently consumed, its R&D would have been longer than its operational life.

Except if someone sees a better neutron multiplier (no Th nor U nor Pu, thanks), we have only Pb and its radioactive waste.

Marc Schaefer, aka Enthalpy