On the article itself: why did it take 6 paragraphs of text to finally mention what the milestone was? I hate this style of article writing, and it's usually a good bullshit-signal for any story. That's a shame, because it looks like this is the Real Thing (in a small way).
Nuclear fusion milestone passed at US lab
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Re: Nuclear fusion milestone passed at US lab
#42Earlier quoted context omitted.
It has the word "nuclear" in it, so the crazies will hate it no matter what it is.
Just take the word "nuclear" out, like they did with Nuclear Magnetic Resonance Imaging. No one will ever suspect a thing ;)
Just laughed at that - I just scanned a patient who was concerned about the radiation dose from the MR scanner in front if me.
Re: Nuclear fusion milestone passed at US lab
#43Re: Nuclear fusion milestone passed at US lab
#44Re: Nuclear fusion milestone passed at US lab
#45There was not an overall net gain.
Direct from the source http://1.usa.gov/1e4Na9Q.
8 kJ out from 1.7 MJ (1700 kJ) in. At the end of the month they were able to get 14 kJ. I believe they are referring to the energy released within the hohlraum.
Also, if you are interested there are privately funded companies doing this, General Fusion (http://www.generalfusion.com/) and TriAlpha Energy (secretive and funded by the Russian govt., but in California). The VC fund I work for has invested in GF and obviously we think there is promise :)
Re: Nuclear fusion milestone passed at US lab
#46Ah, okay, cool! I remember this being announced a while back, but I didn't understand why it was significant if the energy in was less than the energy out. This article helps to clear it up. The missing piece was that I didn't understand how this reactor works. I thought they just blasted a lot of lasers directly at the hydrogen isotopes. Instead, it seems like that use the lasers to shoot something else, which then…
Lasers gets fired at the inner surface of a cylinder (called a hohlraum). The laser heat the surface of the hohlraum which then emits x-rays. The x-rays then deposit energy on the surface of a spherical capsule (this is the "energy absorbed" number).
You start with ~2,000 kJ of laser energy, but some of that gets "backscattered" and never makes it into the hohlraum. Other energy is spent heating the walls of the cylinder. Additionally, some of the x-rays leak out of the hohlraum and do not drive the capsule implosion. After all these losses are taken into account, only about 15 kJ is absorbed in the capsule.
Re: Nuclear fusion milestone passed at US lab
#47It 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 $3,500,000,000 spent so far could have been put into projects geared towards small scale fusion experiments investigating novel confinement schemes.
Like the one I was working on, http://meetings.aps.org/Meeting/DPP07/Event/71002 whose funding has since been cut and has been mothballed.
Re: Nuclear fusion milestone passed at US lab
#48A 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 recapitulates many of the design aspects of a thermonuclear weapon, but does so in a highly controlled lab environment.
I'm a biophysicist. I know a fair amount of engineering, although I'm not a weapons physicist. Nonetheless, after years of reading about the NIF and various fusion projects I've come to believe that there is little justification for their expenditure. In particular, we can do stockpile stewardship without this device, more cheaply, nor does NIF present an economically viable method to production of power at a large scale in even the most rosy predictions.
I still think the experimental design is cool, but I can't see this as a rational expenditure (HUGE opex and capex) compared to other investments we could be making.
Most likely scenario I see in 20 years is that china will be mass-manufacturing small, safe fission reactors and making a mint selling them to the rest of the world. That's got far less reqiurement for massive capex and opex. It's just that the western nations decided to go stupid about fission because OH GOD NUCLEAR MUTATIONS and stop investing in building more reliable, safer, and smaller plants.
Re: Nuclear fusion milestone passed at US lab
#49What 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 generation have a significant impact on price of air travel/sea cargo?
Re: Nuclear fusion milestone passed at US lab
#50tl;dr - Another article about the US nuclear weapons research facility at Lawrence Livermore, AKA NIF, and its sideshow 57th priority. On a related note. It's been really sad to see the US slowly lose its edge in plasma based fusion tech, specifically tokamaks, which seem to be the only credible long-term method of sustaining a fusion reaction for power-plant purposes.
Just a couple quibbles from a former NIF scientist. NIF is much higher on the priority list than that. LLNL is already in the doghouse due to NIF failing to ignite on schedule. As goes the 5 giga-buck NIF, so goes LLNL (and the management knows it). Technologically, I'd put inertial and magnetic fusion about the same place. Even if the physics works, neither has a chamber first wall material that can stand up to the…
Don't get me wrong I think that LLNL and the NIF are doing great work. I just think the work is more weapons based and less energy than we are all lead to believe in the press. and I meant that the Fusion Reactor business is a low priority compared to testing the nuclear stockpile, etc., not NIF in general.
The chamber first wall material keeps me up at night. I think money spent in that area would be really well spent and have many many uses, both in places where you need neutron shielding, and to a lesser extent, protection from heat. When I think of really big, fun, 1960s style energy projects, the only other 'credible' one seems to be laser pro-pulsed power-satellties. Now there is where we might take a lot of the laser tech from the NIF!