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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

#101

Post by acadien »

mrterry wrote: post #95
acadien wrote: post #70

Earlier quoted context omitted.

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 diff…

I thought the goal was to have a self sustaining reaction that would only require laser pulses to hold it in place. Is a continuously pulsed laser necessary to provide thermal energy to drive the reaction?

Also I've read (sorry no citation) that the indirect drive was necessary to ensure even dispersal of the heat generated by the initiating laser blast.

Any clarification would be much appreciated, this isn't my field.

Re: Nuclear fusion milestone passed at US lab

#102

Post by stcredzero »

ReverendBayes wrote: post #62
aeturnum wrote: post #21

Earlier quoted context omitted.

Exactly. If one were to give a hundred billion to fusion research, how much faster would we get results? Would we be funding needs that are critical to help the science into its next phase, or just be funding the N next-best ideas that previously were set aside? For a community that has such high praise for bootstrapping businesses, there's a surprising love of throwing money at unproven scientific research avenues.…

If we have fusion in 30 years instead of 60 years, we have colonization of the solar system happening in our lifetimes. We'd have the economic rationale for removing all military engagement in the middle east. We have 30*380 billion on petro cost savings here in the U.S: http://www.fuelfreedom.org/the-real-foreign-oil-problem/oil-... God knows how much CO2 we remove from the atmosphere. 100 billion sounds cheap to me…

> We'd have the economic rationale for removing all military engagement in the middle east.

This only works if fusion can make petroleum cease to be a strategic resource.

Re: Nuclear fusion milestone passed at US lab

#103

Post by mrterry »

jimmcslim wrote: post #49

What would be the impact of a 'fusion economy', assuming realistic evolution of the technology for the purposes of commercialisation? (i.e. I'm assuming "Mr Fusion" powerplants on top of one's DeLorean aren't ever going to be practically feasible). What would such a world look like? Does it promote world peace; through greater energy security for nations, would less reliance on fossil fuels for baseload electricity g…

it is unlikely that fusion energy will be cheaper than current tech. however, it does not emit CO2, is not a proliferation risk, and cannot have a nuclear meltdown.

Re: Nuclear fusion milestone passed at US lab

#104

Post by [deleted] »

mrterry wrote: post #95
acadien wrote: post #70

Earlier quoted context omitted.

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 diff…

[deleted]

Re: Nuclear fusion milestone passed at US lab

#105

Post by mrterry »

acadien wrote: post #101
mrterry wrote: post #95

Earlier quoted context omitted.

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 diff…

I thought the goal was to have a self sustaining reaction that would only require laser pulses to hold it in place. Is a continuously pulsed laser necessary to provide thermal energy to drive the reaction? Also I've read (sorry no citation) that the indirect drive was necessary to ensure even dispersal of the heat generated by the initiating laser blast. Any clarification would be much appreciated, this isn't my fiel…

ICF is intrinsically pulsed (magnetic confinement like ITER is completely different). You use a laser to spherically compress a 1 mm diameter spherical capsule. The capsule implodes, stagnates, and blows (releasing energy in the explosion). Then you do do it again 0.1 seconds later.

NIF uses an "indirect drive" design. Instead of directly illuminating the spherical target with a bunch of lasers, you blast the inner surface of a gold cylinder with the shell at the center of the cylinder. The cylinder gets hot, emits x-rays, which are absorbed by the capsule. The x-ray drive tends to be "smoother" than direct illumination.

The big problem with ICF is hydrodynamic stability. It is like trying to squeeze a water balloon with your fingers. If you don't squeeze it perfectly symmetrically, it will squirt through your fingers and pop rather than getting compressed by a factor of 20.

Re: Nuclear fusion milestone passed at US lab

#106

Post by nikatwork »

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…

> It's just that the western nations decided to go stupid about fission

I have many highly intelligent friends who subscribe to your view. Unfortunately they forget that fission is only as safe as the weakest link, and the consequences of failure are severe, especially when near a water source.

I'm not talking about crumbling old soviet-era reactors or even older Japanese ones. Witness Australia's only nuclear facility: http://www.abc.net.au/news/stories/2010/06/01/2914548.htm?si...

My fave quote from the article: "None of our instruments could measure it - it was way off scale. We cleaned up everything and we still couldn't get the dose down."

You called out the need for more reliable, safer, and smaller plants. I would argue that there needs to be a significant improvement before fission is publicly acceptable.

Re: Nuclear fusion milestone passed at US lab

#107

Post by hyperbovine »

nikatwork wrote: post #106
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…

> It's just that the western nations decided to go stupid about fission I have many highly intelligent friends who subscribe to your view. Unfortunately they forget that fission is only as safe as the weakest link, and the consequences of failure are severe, especially when near a water source. I'm not talking about crumbling old soviet-era reactors or even older Japanese ones. Witness Australia's only nuclear facili…

If the Japanese can't do it safely, it can't be done safely.

Re: Nuclear fusion milestone passed at US lab

#108

Post by gameshot911 »

mrterry wrote: post #105
acadien wrote: post #101

Earlier quoted context omitted.

I thought the goal was to have a self sustaining reaction that would only require laser pulses to hold it in place. Is a continuously pulsed laser necessary to provide thermal energy to drive the reaction? Also I've read (sorry no citation) that the indirect drive was necessary to ensure even dispersal of the heat generated by the initiating laser blast. Any clarification would be much appreciated, this isn't my fiel…

ICF is intrinsically pulsed (magnetic confinement like ITER is completely different). You use a laser to spherically compress a 1 mm diameter spherical capsule. The capsule implodes, stagnates, and blows (releasing energy in the explosion). Then you do do it again 0.1 seconds later. NIF uses an "indirect drive" design. Instead of directly illuminating the spherical target with a bunch of lasers, you blast the inner s…

>The big problem with ICF is hydrodynamic stability. It is like trying to squeeze a water balloon with your fingers. If you don't squeeze it perfectly symmetrically, it will squirt through your fingers and pop rather than getting compressed by a factor of 20.

Well said.

Re: Nuclear fusion milestone passed at US lab

#109

Post by scott_s »

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.

Where would you rather work: a nuclear power plant, or a coal mine? I know I would rather work in a nuclear power plant; it is far safer.

Re: Nuclear fusion milestone passed at US lab

#110

Post by ballard »

NegativeK wrote: post #96
cyanoacry wrote: post #92

Earlier quoted context omitted.

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.

It's an extremely misleading half-truth. Worse, Q must be an order of magnitude greater than 1 IIRC to be economically viable.
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