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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

#121

Post by stormbrew »

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…

My layman's understanding of the subject is that you want (and get) anything but a self-sustaining reaction with fusion, and that's actually one of its safety features compared to fission (where a chain reaction is allowed to happen in a controlled way -- if something goes wrong the reaction keeps going, out of control).

You do want to use the energy from one reaction to power the next, but not directly. No one's actually trying to create a star on the surface of the earth.

As with you, though, not my field so someone who knows better can feel free to correct me.

Re: Nuclear fusion milestone passed at US lab

#122

Post by nikatwork »

bcoates wrote: post #113
nikatwork wrote: post #106

Earlier quoted context omitted.

> 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…

That appears to be an accident handling the output of an isotope manufacturing reactor, not anything involving a power reactor. > I would argue that there needs to be a significant improvement before fission is publicly acceptable. I would argue that fission is already held to a standard well above that of almost any human endeavor, even those with roughly similar risk profiles (compare almost any form of mining, or…

> That appears to be an accident handling the output of an isotope manufacturing reactor, not anything involving a power reactor.

That is irrelevant to my point, which is that the biggest risk to reactor safety with current fission tech is human error and negligence.

> compare almost any form of mining

The only form of mining comparable in terms of potential environmental damage is ocean oil drilling[1], which I also oppose.

The point is - human nature (re: greedy and negligent idiots) makes current reactor tech unsafe. The potential fallout (pun intended) is not worth the significant risk.

[1] http://en.wikipedia.org/wiki/Deepwater_Horizon_oil_spill

Re: Nuclear fusion milestone passed at US lab

#123

Post by pdonis »

rlucas wrote: post #116
hyperbovine wrote: post #107

Earlier quoted context omitted.

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

It wasn't "the Japanese" that didn't do it safely at Fukushima. It was GE, which is about as American as you get, along with Toshiba and Hitachi. Also it was the 1960s, which is the age of the technology deployed in these relative archaisms. See http://blog.rlucas.net/tech_and_market_reflections/fukushima...

It wasn't "the Japanese" that didn't do it safely at Fukushima. It was GE

Was GE responsible for the siting of the backup diesel generators and switchgear behind a seawall that was overcome by the tsunami? That was the root cause of all the problems; it wasn't anything to do with the reactor design itself, other than the fact that it needed active cooling after shutdown (which PWR designs from the same time period also did).

(That said, I agree the BWR design is outdated and modern designs with passive safety features are much, much better.)

Re: Nuclear fusion milestone passed at US lab

#124

Post by ck2 »

Is it plausible this lab is trying to figure out how to make nuclear explosions without the radiation?

Because just imagine how terrifying the world would become from a superpower that didn't have to fear the radiation aftermath.

Fusion research seems like just a complete cover up.

Re: Nuclear fusion milestone passed at US lab

#125

Post by moca »

"the amount of energy released through the fusion reaction exceeded the amount of energy being absorbed by the fuel" means it is at least 4 orders of magnitude away from being useful.

Since we still depends on nuclear power for decades to come, it is much cost effective to invest safer and cleaner nuclear fission reactors. The kind of fast reactor that can burn down nuclear waste so we don't need to build nuclear waste storage system, which nobody knows how to build anyway. That would give us power supply for several centuries (along with renewable energy). Too many countries wasted too much money on fusion reactors for decades, while we are still running nuclear reactors designed/built more than 30 years ago. Just wrong priority order.

Re: Nuclear fusion milestone passed at US lab

#126

Post by raorao »

gameshot911 wrote: post #108
mrterry wrote: post #105

Earlier quoted context omitted.

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.

I agree with your general philosophy towards ICF.

Re: Nuclear fusion milestone passed at US lab

#127

Post by drjesusphd »

nickpinkston wrote: post #19

This is awesome news - I visited the NIF a few months ago and they seemed a little downtrodden when asked about results. I bet they're all cocky now! They also told us that the lasers they use, if built with modern tech today, would actually only be the size of a 40' cargo container (as opposed to like 100K sq-ft building), and cost like 1000x less. Pretty epic... If we invested in fusion power like we did water powe…

They've been cocky many times before. After reading this article, I'm not optimistic that they've learned their lesson.

Re: Nuclear fusion milestone passed at US lab

#128

Post by drjesusphd »

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

So what? What if the fueld didn't absorb anything? What do they mean by "absorb", anyway? This article is lacking in details, peer-reviewed literature, or even the names of scientists willing to stake their reputation on this claim.

The BBC should know better.

Re: Nuclear fusion milestone passed at US lab

#129

Post by drjesusphd »

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…

I think you're unfairly dismissing magnetic confinment, the limited supply of fissionable material, and the unprecedented issues that accompany the management of dangerous material (or anything for that matter) for 10,000 years.

Fusion research is worthwhile. Of course it's not the only path to sustainable energy, but it's one of the most promising.

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