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Nuclear fusion milestone passed at US lab

bbc.co.uk

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Re: Nuclear fusion milestone passed at US lab

#91

Post by crystaln »

beloch wrote: post #68
dekhn wrote: post #48

A good place to start if you want to understand the purported rationale for the NIF (stockpile stewardship), I suggest reading and understanding this light introduction to modern nuclear weapons. http://en.wikipedia.org/wiki/Thermonuclear_weapon (the rhodes books, Making of the Atomic Bomb is required background reading, as is Dark Sun, if you want to get into the backstore). In particular: The NIH experiment recapit…

The NIF is probably more useful for coming up with new fusion bomb designs than for stockpile stewardship, as you say, but what makes you say hot fusion can never be economically viable? The sun is proof that nature can do this on a grand scale! It may be a long ways off, but "a long ways" becomes "never" without experimental work like the NIF. Yes, the U.S. is probably doing this primarily to create new weapons just…

Coal power is more deadly than fission power?

When has coal power ever created the sort of crisis that occurred in Fukushima?

Because of fission reactors, the safety of entire regions of the world is dependent on a consistent power supply and lack of human error, something that clearly we can not rely on. In the event of a cosmic emp or major meteor strike, these power plants are at risk.

Re: Nuclear fusion milestone passed at US lab

#92

Post by cyanoacry »

sam wrote: post #47

It is an important milestone. But to have a commercially viable fusion reactor, you'll need a factor of 50-100 more energy out than in to make up for inefficiencies in electricity generation using this kind of scheme. The real story here is that this facility allows the US to do nuclear weapons research without violating the nuclear test ban treaty. If the goal was to develop a commercially viable fusion reactor, the…

This is definitely true, and the BBC totally omitted these facts. The official NIF announcement[1] tried a little bit to cover their tracks. They posted some flashy numbers about the total energy output from neutrons, but nestled in the bottom of the page is the total energy dumped into the entire system:

1.7 megajoules.

In comparison, the fusion power produced was a paltry 8 kilojoules, which they compare to the "energy required to form the plasma".

For this technology to be actually effective, there needs to be a multiplier of several thousand. As other commenters have mentioned, this is mostly just nuclear weapons development.

[1] http://www.physicstoday.org/daily_edition/politics_and_polic...

Re: Nuclear fusion milestone passed at US lab

#93

Post by TylerE »

sam wrote: post #47

It is an important milestone. But to have a commercially viable fusion reactor, you'll need a factor of 50-100 more energy out than in to make up for inefficiencies in electricity generation using this kind of scheme. The real story here is that this facility allows the US to do nuclear weapons research without violating the nuclear test ban treaty. If the goal was to develop a commercially viable fusion reactor, the…

If we could get a fusion design that works a bit over unity, couldn't you, well, chain them?

E.g. 1MW basic plant that drives a 1.5MW plant that drives a 2.25MW -> 4 -> 6 -> 9 etc, however many stages you need.

Re: Nuclear fusion milestone passed at US lab

#94

Post by mquander »

crystaln wrote: post #91
beloch wrote: post #68

Earlier quoted context omitted.

The NIF is probably more useful for coming up with new fusion bomb designs than for stockpile stewardship, as you say, but what makes you say hot fusion can never be economically viable? The sun is proof that nature can do this on a grand scale! It may be a long ways off, but "a long ways" becomes "never" without experimental work like the NIF. Yes, the U.S. is probably doing this primarily to create new weapons just…

Coal power is more deadly than fission power? When has coal power ever created the sort of crisis that occurred in Fukushima? Because of fission reactors, the safety of entire regions of the world is dependent on a consistent power supply and lack of human error, something that clearly we can not rely on. In the event of a cosmic emp or major meteor strike, these power plants are at risk.

Coal power creates that kind of crisis every day, so we don't bother calling it a crisis anymore.

A total of 240,000 years of life were said to be lost in Europe in 2010 with 480,000 work days a year and 22,600 "life years" lost in Britain, the fifth most coal-polluted country.

http://www.theguardian.com/environment/2013/jun/12/european-...

Re: Nuclear fusion milestone passed at US lab

#95

Post by mrterry »

acadien wrote: post #70
sam wrote: post #47

It is an important milestone. But to have a commercially viable fusion reactor, you'll need a factor of 50-100 more energy out than in to make up for inefficiencies in electricity generation using this kind of scheme. The real story here is that this facility allows the US to do nuclear weapons research without violating the nuclear test ban treaty. If the goal was to develop a commercially viable fusion reactor, the…

Finally someone that's actually in the fusion field. Could you say whether or not the NIF research represents a practical path towards a fusion based power source? My understanding is that it would at least be capable of capturing some much needed high pressure empirical data necessary for validating theory. On a side note concerning the NIF funding, the US gov will spend huge sums of money studying Nuclear weapons (…

I've worked in ICF for a nearly a decade. I think NIF research is a necessary step to a ICF based power source. If NIF demonstrates ignition, it can be used to validate our physics models of ICF (turbulence, fusion product transport, thermal conduction, etc). These physics questions are shared by all ICF approaches. However, a fusion power plant will use entirely different laser technology [1], and most likely a different target design [2]. After showing that the physics works, there is still a lot of engineering work needed before building a reactor.

[1] An ICF power plant will be pulsed at 1-10 Hz. NIF is a flash-lamp pumped glass laser, which takes ~12 hours to cool between shots. A power plant would likely be diode-pumped sold state laser since these can meet the required repitition-rate.

[2] The indirect drive target that LLNL is pursuing on NIF is not very efficient. You spend a lot of energy heating the hohlraum. Directly driven targets (blast the capsule directly rather than heating a gold can to make x-rays) should be much more efficient. There are also several ideas for ways to ignite a target more efficiently (shock ignition, fast ignition), but these need additional laser hardware.

@sam Though I work in ICF, I was sad to see the innovative confinement concepts (magnetic confinement) cut a couple years ago. I think it is short sighted. Fusion need to work and get smaller and we should keep our options open. Hope you managed to get a thesis out before the walls fell.

Re: Nuclear fusion milestone passed at US lab

#96

Post by NegativeK »

cyanoacry wrote: post #92
sam wrote: post #47

It is an important milestone. But to have a commercially viable fusion reactor, you'll need a factor of 50-100 more energy out than in to make up for inefficiencies in electricity generation using this kind of scheme. The real story here is that this facility allows the US to do nuclear weapons research without violating the nuclear test ban treaty. If the goal was to develop a commercially viable fusion reactor, the…

This is definitely true, and the BBC totally omitted these facts. The official NIF announcement[1] tried a little bit to cover their tracks. They posted some flashy numbers about the total energy output from neutrons, but nestled in the bottom of the page is the total energy dumped into the entire system: 1.7 megajoules. In comparison, the fusion power produced was a paltry 8 kilojoules, which they compare to the "en…

The BBC did say:

> the amount of energy released through the fusion reaction exceeded the amount of energy being absorbed by the fuel

As soon as I saw that, I immediately understood that they're nowhere near breakeven -- much less power generation.

Re: Nuclear fusion milestone passed at US lab

#97

Post by rpedela »

NhanH wrote: post #90
rpedela wrote: post #15

Earlier quoted context omitted.

Pick your favorite energy technology (oil, wind, solar), it still applies.

It's quite a bit harder to run out of wind and solar.

Yeah. My comment has nothing to do with finite or infinite amount of any energy technology but rather that my original comment applies to fusion competing with the price of any existing energy technology such as coal, oil, wind, solar, etc.

Re: Nuclear fusion milestone passed at US lab

#98

Post by jameshart »

afterburner wrote: post #78
trevelyan wrote: post #66

Earlier quoted context omitted.

In situations of depressed aggregate demand, it really doesn't matter what you spend the money on -- you could even bury it in the ground like gold and "pay" people to dig it up. Whatever you fund is essentially a free lunch. You don't want to wait months though, which is why "shovel-ready" matters and this sort of research loses out to other sorts of projects. That said, less guns and more fusion would be nice.

Well, I get the impression billions spent on fusion research doesn't really employ that many more people, it just spends more on expensive resources. Maybe that has a knock-on effect, but using the money on more labour-intensive work (skilled or otherwise) is still probably a better use. Such as, building and installing a heck of a lot of cheap solar panels.

Exactly. Say you go to a fusion laboratory that employs the top ten fusion scientists in the world, with a current budget of a few hundred million dollars, and you say to them "I've got 2 billion here in additional funding for you. You need to spend it in the next few months because I'm trying to stimulate an economy right here."

Does that hire you forty more world class fusion scientists? Are there forty more world class fusion scientists?

Are those scientists going to go "Fantastic! We'll just order up three more of these experimental fusion reactor rigs, here are the plans, we'll start hiring engineers and buying up electronic components from the local silicon fab down the road driving all that money into economic productivity for you!" - unlikely. They already have one experimental fusion reactor. Three more the same aren't going to get them anywhere any faster. They won't know what the next one should look like until they've finished getting results out of this one.

Maybe they just spend it all on repainting the lab, buying new office furniture, getting in catered lunches - you might see a marginal improvement in fusion research productivity, and certainly there's a local economic stimulus which was the idea there, but you're not getting the valuable long term capital value of, say, using the money to rebuild a few bridges.

Even if it turns out your ten fusion scientists have a ready proposal to build the next generation experimental fusion reactor, plans are drawn up and costed, and all they need is you to hand over that check for two billion, if they then go ahead and order the parts from China, subcontract a bunch of German engineering firms to build the cooling systems, and get the heavy steelwork welded together in Korea, your stimulus effect just disappeared overseas.

Of course, if that experimental fusion reactor turns out to be THE ONE that creates viable economic fusion power, maybe that's worth the 2 billion. But that's not stimulus spending, that's gambling on an investment.

Re: Nuclear fusion milestone passed at US lab

#99

Post by mrterry »

sam wrote: post #47

It is an important milestone. But to have a commercially viable fusion reactor, you'll need a factor of 50-100 more energy out than in to make up for inefficiencies in electricity generation using this kind of scheme. The real story here is that this facility allows the US to do nuclear weapons research without violating the nuclear test ban treaty. If the goal was to develop a commercially viable fusion reactor, the…

"50-100 more energy out than in to make up for inefficiencies in electricity generation using this kind of scheme."

Completely true. Theoretically, the NIF target has enough fuel to produce 10-20x the amount of laser energy driving it. Once things work, it isn't a huge step to get to an energy gain (energy_out/energy_in) of ~50. That said, the real world is always more complicated and NIF has yet to ignite.

Re: Nuclear fusion milestone passed at US lab

#100

Post by dekhn »

chris_mahan wrote: post #88
dekhn wrote: post #72

Earlier quoted context omitted.

Whether the sun is capable of fusion isn't super important. We can take advantage of that, but it doesn't mean we can build many safe plants based on an evolution of the NIF design. If your alternative fuel requires hundreds of billions of dollars of investment in the future, just to show viability of the basic research concept, before it can actually be useful, you will be at a massive competitive advantage relative…

A hundred billion dollars is not a whole lot of money. We spent many, many times that on the wars in Iraq and Afghanistan, and the results there are passable at best.

(your comparison is nonsensical for many reasons)

A hundred billion dollars is a lot of money. The annual budget of NIH is ~$30B and it funds a high fraction of the most advanced biological research worldwide. The DOE also has a budget $30B and funds (along with this project) many other projects including alternative energies, advanced computing and the Human Genome Project. NSF is (only!) another $7B, leaving around $33B addition funds for a diverse research portfolio.

This kind of expenditure is required to maintain US at or near the highest level of technology research in the world (other countries can compete with us in many ways, such as lower labor costs). There are things that can only be physically done in a single location in the US and nowhere else in the world- and it will be that way until on of the postdocs goes back to Europe or Asia and replicates the result in their lab.

So yes, $100B is a lot of money- and that's the kind of investment that often ends up benefiting the US (and other) economy. The fusion research-- to the extent that what NIF is doing is translatable to other domains-- doesn't really meet this sniff test.

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