BBC: Is fusion power really viable? (concerns about tritium)

[OKIsItJustMe]

http://news.bbc.co.uk/2/hi/science/nature/8547273.stm

Page last updated at 14:02 GMT, Friday, 5 March 2010

Is fusion power really viable?

...

Supplies come principally from nuclear reactors, specifically Canadian heavy water reactors. They can produce enough tritium to supply current experimental fusion plants but not enough for commercial production.

Jan Beranek of Greenpeace claims that, "to sustain a reaction for a year for just one reactor it would need to burn 50 kgs of tritium... at the moment we are able to get one kg for about $30 million (£20 million)".

And that price is expected to rise. So where could affordable fuel come from?

Professor Cowley admits: "That's part of the problem that we haven't done yet but we do know how to do it because it's been done with nuclear reactors."

...

[phantom power]

1. More immediate question is "will it ever really work?"

[OKIsItJustMe]

2. The answer appears to be "Yes"

http://news.bbc.co.uk/2/hi/science/nature/8547273.stm

...

As Professor Mike Dunne, head of Europe's laser fusion project says, "The first credible attempt is now just a few months away after 50 years of trying. Incredibly exciting times."

...

[phantom power]

11. With total and sincere respect for all fusion R&D guys everywhere, will believe it when I see it.

It's just, you know... really fucking hard.

[Statistical]

12. Fusion or electrical power from fusion?

The "fusion guys" have sustained a fusion reaction.
The problem is it has a Q value of 0.7

Which means for every unit of energy used to heat the plasma up the fusion reaction produces 0.7 units of energy.

Q=1 means energy required to heat fusion is equal to energy produced from fusion.
Q=1 is also called "ignition" because it is a self sustaining reaction at that point.

There is a timeline for getting to Q=1 and beyond.

Pressure can be increased by increasing magnetic fields so the next reaction being constructed will have a magnetic field strenth that is triple what any other reactor has achieved.

http://www.iter.org/default.aspx

http://en.wikipedia.org/wiki/ITER

If that works the next step is DEMO
http://en.wikipedia.org/wiki/DEMO

DEMO is a prototype commercial power reactor.

I concede that power from fusion may never work but fusion is certainly possible which is pretty cool from a science point of view. Humans have been able to safely create and control conditions that replicate the pressure and temperature inside the sun.

[OKIsItJustMe]

14. Have you seen an electron?

Do you believe they exist? (Why?)

We know fusion happens, simply look into the sky, day or night to see it at work.

We've been fusing atoms ourselves for almost 60 years now. http://en.wikipedia.org/wiki/Ivy_Mike

The really hard part is harnessing it for productive use, so that, "this greatest of destructive forces can be developed into a great boon, for the benefit of all mankind."

Of course, even if everything goes as planned at https://lasers.llnl.gov/">NIF, a practical power plant would be years away.

[Statistical]

3. Simple you make tritium.

1n + Li7 → T + He + 1n

OR

1n + Li6 → T + He

Lithium is about $700 per kg, occurs naturally, and is rather abundant.

The problem so far has been the "1n" part. You need a lot of neutrons. Most neutrons will miss the Lithium. We currently have no cheap, reliable method of generating nuetrons.

Neutrons are produced inside a reactor but any tritium produces is diluted with millions of gallons of water making economic recovery difficult.

Fusion reactors have large amount of "spare" neutrons so designed a reactor that can be self-sustaining as the physisct described is not impossible.

Essentially you would just need to add a tiny amount of lithium each year to replace the tritium that has fused.

[GliderGuider]

5. Is tritium being commercially manufactured by this process anywhere?

Reaction diagrams are easy...

[OKIsItJustMe]

7. Similarly

http://news.bbc.co.uk/2/hi/science/nature/8547273.stm

...

Cowley and his colleagues expect fusion reactors to become self-sustaining, 'breeding' their own fuel supply.

"The principles are right, but there's a lot of difference between principles and practice and that's where we have to do our work," he says.

...

[Statistical]

8. The problem is a source of concentrated neutrons at a low cost.

Most neutrons will miss the Lithium so you need a LOT of neutrons.

They only source that currently exists is inside a nuclear reactor.

Producing tritium is easy. Just ask Vermont Yankee. however tritium density is very low. It is a few kg grams of tritium mixed with millions of gallons of water.

A fusion reactor has a massive amount of spare neutrons. Using some of those to convert a tiny amount of lithium each year into tritium which is then added to reactor to keep tritium concentrations up is a challenge but not an impossible one.

No commercial fusion reactor is going to "buy" tritium from outside source when they can make it internally. Currently getting the fusion reactor working is more important so they do buy tritium (mainly from Canada and India). That is the difference between a prototype and commercial reactor.

[OKIsItJustMe]

6. And we need more helium

http://www.google.com/search?q=helium+shortage

[Statistical]

9. The amount of tritium needed wordwide is tiny (outside of weapons productions).

A 1000MW fusion reactor only "consumes" about 20kg of tritium per year.

Thus replacing all fossil fuel plants & nuclear fission plants in the US with a hypothetical D-T fusion reactors would only need in the ballpark of 7 to 8 tons of Tritium a year.

So that isn't going to produce much usable (or cheap) Helium.

[OKIsItJustMe]

10. (Must remember to use those :irony: tags more!)

I guess it's time to start wasting tritium. :irony:

[On the Road]

4. I Would Love for Fusion to be Viable,

but the technical obstacles are really daunting.

Resources might be better spent in developing hydrogen-boron or some other type of aneutronic fusion. There are certainly technical obstacles there, too, but the potential might be greater.

The most feasible kind of atomic energy is probably thorium fission. It has much lower risk of radiation and weaponization, and most of the technology has been worked out with uranium.

[OKIsItJustMe]

16. I'm still pulling for polywell/"Bussard" fusion

http://en.wikipedia.org/wiki/Polywell#Possibility_of_net_power

(preferably using boron.)

[GliderGuider]

24. Not me.

Given the planetary havoc we have been able to wreak using expensive low-grade sources of energy, I shudder to think of the possibilities of fusion.

"Son, you can not have the keys to the Corvette until you've grown up enough to drive it responsibly."

[Statistical]

26. On the other hand large amounts of low cost energy could change everything.

Take recycling for example. Recycling is energy intense. Higher the cost of energy the higher the cost of recyled goods.
Ultra cheap energy could make recycling cheaper than mining.

EV costs about 1/3 that of internal combustion engine vehicle. That is at current prices. If Fusion works it would be more like 1/10th. If cost of gasoline doubles it would be more like 1/20th.

If your choice is $250 a year to power an electric vehicle or $5000 for gasoline one everyone will be "green". They won't be green for green sake they will be green because doing the right thing would be cheaper.

We know how to scrub CO2 from the atmosphere, however it is energy intensive. To do it on a massive scale would require a massive amount of emission free energy.

I am not saying fusion electricity will ever be viable but spending a small amount of money for the potential is worth it. It could change everything for better.

[OKIsItJustMe]

27. Better "the devil you know?"

Barring some breakthrough technologies, we're in for a load of hurt. Period.

With some breakthrough technologies, we may easily still be in for a load of hurt.

[On the Road]

29. The Result of a Breakdown in a Fusion Reactor --

if one is ever built -- is that it will go dark. To be self sustaining without containment, it would be a star millions of times bigger than the earth.

[GliderGuider]

32. That's not the problem I'm concerned about.

I know that. I'm concerned about what we might do with it.

[Statistical]

33. The problem isn't energy it is dirty energy.

The problem is that until now clean energy has been far more expensive than dirty energy. We are at the tipping point where clean energy is reaching parity with dirty energy.

Utilities look for lowest cost. Right now that is coal, until that changes or you ban coal they will burn it.
For transportation nothing has replaced gasoline because it is "cheap". Sure people feel some pain at the pump if gasoline is $3.00 but even then it is cheap compared to a cleaner method of transportation.

If tomorrow you could (via any method wind, solar, fusion, zero point energy) produce electricity at say 1 cent per kwh (1/5th of current prices) it would radically change everything.

Coal would die within a couple years. Why would someone burn coal at 3.0 cents per kwh when they could produce energy at 1 cent per kwh.

The problem for the world has been the double edged sword of fossil fuels.
Fossil fuels are amazingly dense sources of energy but they aren't clean.

[GliderGuider]

36. Dirty energy is "a" problem, but it isn't "THE" problem. See #35. nt

[On the Road]

43. Well the Basic Reaction Has Already Been Weaponized and Deployed

I dont know what more damage it could do.

[GliderGuider]

44. Thermonuclear weapons are unlikely to destroy the planetary biosphere

Accelerated human activity powered by prodigious amounts of fusion-generated electricity could. It might take a while, but such unlimited human activity could conceivably finish the job we've alrady begun.

It may be contrarian, but I believe that the peaceful uses of fusion power are far more potentially dangerous than the military uses.

[TheWraith]

31. That's contrary to all logic.

A large portion of our problems on this planet are due to the fact that we're using "cheap" poisonous, environment destroying sources of energy, and we still don't have enough of it to do things that need to be done.

Clean unlimited power would not just save the hundreds of thousands of people a year who are killed by coal, and stop or slow down global warming, but would provide energy for things like desalination of drinking water.

[GliderGuider]

35. There's a different point of view on that.

From that point of view the majority of the human-caused problems on the planet are, at their core, human problems rather than technological ones. We merely use the technology we develop and the energy sources at hand to shape the world as we wish it to be shaped. All other "problems" like AGW and mountaintop removal are secondary effects -- merely symptoms of our underlying urge to dominate, control and shape our planetary environment. If we got rid of one intended consequence another would appear to take its place. The higher the technology and the more energy we use, the greater the consequences.

[OKIsItJustMe]

37. Let me try a different tack

One example:

Thanks to fossil fuels, we have fleets of "http://en.wikipedia.org/wiki/Factory_ship">factory ships," scouring the oceans for food, and depleting them in the process. If those ships were powered by on-board fusion reactors, the problem of "AGW" might be eased to an extent, but the problem of http://www.google.com/search?q=fishery+depletion">fishery depletion might (potentially) be made even worse.

[GliderGuider]

40. One of my favourite examples. Thanks. nt

[TheWraith]

38. A viewpoint to which the inevitable conclusion is mass suicide.

Because absent a move backwards in time, our development isn't going away. So therefore the ideal solution is one which allows us to grow and develop without killing the environment.

[GliderGuider]

39. Why would you say that? To me the inevitable conclusion is

that we must adjust our wants and needs so that our behaviour takes the rest of the planet into account. If we do that, a new balance will be reestablished over time that might prove sustainable. Unless we make that adjustment, though, no amount of new energy will help. Suicide is not required.

[OKIsItJustMe]

42. However, without some technological breakthrough(s)

I believe the balance we arrive at may be the zero state.

[Dogmudgeon]

13. Don't we now have neutron-source generators?

I am behind on my reading, but I'd heard that we have new technology to produce neutrons. Here is a http://en.wikipedia.org/wiki/Neutron_generator">Wikipedia article on neutron generators; I'm sure that it leaves out some of the details, so if anyone can fill me, in, I'd appreciate it.

--d!

[tech9413]

15. Here's another idea that was implimented decades ago

Liquid Fluoride Thorium Reactor. http://en.wikipedia.org/wiki/Molten_salt_reactor
Much safer, waste has a much shorter half life(like a few hundred years), self regulating(no chance of melt down). The technology was cast aside by the military industry because it couldn't be used to breed weapons grade material.

[Statistical]

18. Thorium is a good replacement for uranium but it still is fission reactor.

Which means it is very inefficient, produces long lived waste, and there is always a risk of mechanical failure.
This is coming from someone who supports nuclear industry.

Fusion Electrical Power may never work but the amount of money being spent on Fusion research is a drop in the bucket of global economy.

Fusion power would be a world changer in a way that Thorium never can be.
It is worth putting 0.00000000001% of our chips on the longshot.

So while we build nuclear reactors, wind, solar today we should still let pure researchers do what they do best and reach for the brass ring.

[OKIsItJustMe]

19. Decent explanation can be found here:

http://www.wired.com/magazine/2009/12/ff_new_nukes/

[bananas]

41. That wired article is full of errors

For example: http://www.democraticunderground.com/discuss/duboard.php?az=show_mesg&forum=228&topic_id=60916&mesg_id=60973

[Javaman]

17. Sure it is, it will be ready in 20 years. nt

[Statistical]

20. Not quite.

The most advanced D-T fusion reactor has a Q value of 0.7.

Q value of 1 is "ignition" = self sustaining reaction that neither produces nor consumes energy.

For commercial electrical power a Q value of 15 is necessary. Q value of 20-25 would be preferable.

Construction on ITER has begun and it should be operational in 2018.

Goals include:
* "ignition" = self sustaining reaction
* sustained fusion reaction of 500MW for 500 seconds
* sustained Q value of 5
* Peak Q value of 10

http://en.wikipedia.org/wiki/ITER

If research results are promising the next step is DEMO
Demo is a prototype for commercial fusion power.
Timeline is planning in 2017, Construction in 2024. Online in 2033.

Goals include:
* sustained fusion reaction of 2000MW indefinitely
* Tritium creation and resupply onsite
* Q value of 25 sustained
* power capture into electrical energy research

http://en.wikipedia.org/wiki/DEMO



Based on that the goal would be roll-out of fusion plants around 2040-2050.

[Javaman]

22. I guess you missed the joke. nt

[OKIsItJustMe]

23. The British say maybe sooner than that

http://www.democraticunderground.com/discuss/duboard.php?az=view_all&address=115x232026

From The Sunday Times
February 21, 2010

UK plans first nuclear fusion power plant

Jonathan Leake

BRITISH scientists have drawn up plans to build the world’s first nuclear fusion power station. They say it could be pouring electricity into the National Grid within 20 years.

...

[Statistical]

25. Maybe but I doubt it.

The ITER project has funding for the largest players in fusion space (US, Russia, EU, Japan, Korea).

If they think it will be 40 years I doubt (no offense to the Brits) that the UK will do it in half the time.

Then again if they do it.... I will be singing their praises.

[OKIsItJustMe]

28. The British are proposing to use lasers

(Like the NIF.)

It's the apparent success of the NIF that leads to their bold prediction.

http://www.timesonline.co.uk/tol/news/science/article7034945.ece

...

The Americans designed NIF for a very different purpose from power generation. Its aim is to simulate nuclear explosions so scientists can carry out weapons research. This means that it can trigger only one fusion explosion at a time.

Dunne’s vision for Hiper is to feed a continual stream of fuel pellets into the reactor, blasting them with lasers in rapid succession to generate a constant stream of nuclear fusion explosions.

“The lasers will crush the 2mm pellet to a hundredth of its size in a billionth of a second, making it 10 times hotter than the middle of the sun,” he said.

Under such conditions the hydrogen atoms that make up the fuel are ripped apart, creating a “plasma” of electrons and hydrogen nuclei which collide and interact at high speed.

...

[Statistical]

30. Well we will see. I have always been a fan of parallel research.

The main thrust being "hot" Tokamak fusion.
That doesn't mean we shouldn't try other approaches (laser, polywell, etc).
Rarely do you know where the giant leaps in understanding come from.

That is why I am such a big proponent of "all of the above" when it comes to clean energy.

Humans rarely predict the future accurately. Pursuing a single avenue is a risk. The risk being inflexibility when it comes to a future that doesn't work as expected.

Take photovoltaic in the 1960s. The cost was about $100,000 per watt had less than 8% efficiency and little commercial application (other than niche like spacecraft and solar calculators). Fission was the big promise. It was going to replace 99% of all other forms of power in a couple decades. The US was going to build 400, 500, 600 nuclear plants.

Researching PV was a longshot but scientists still did. Major breakthroughs happened and home installed PV arrays are getting close to break even with the grid (without incentives).

So "all of the above" please!

[OKIsItJustMe]

34. I (largely) agree

However, I can also see a benefit in setting as priorities a few promising solutions, taking into account how likely we think they are to bear fruit and the potential benefits if they do.

So, "several of the above," please!

[kristopher]

21. Short answer is "No".

Viable fusion power doesn't exist. It may be viable some day in the future, but it is still in the category of an experimental long shot.