4 ms·

As a nuclear fusion ignorant, where is the small print here? What's the catch, drawback, issue that it will make actually nonviable ?

beefman 5y ago
They made 50 neutrons from this shot! You can make billions per second, steady state, with a tabletop device plugged into a standard outlet. Edit: Fusion makes ~ 10^15 neutrons for every watt-hour of energy released (for the easiest kind of fusion) https://www.wolframalpha.com/input/?i=1+Wh+%2F+17.6+MeV https://www.wolframalpha.com/input/?i=1+Wh+%2F+17.6+MeV
regularfry 5y ago
I can imagine the downsides of accelerating the fuel that hard at the target and missing might be fairly entertaining.
colechristensen 5y ago
The small print is that you can achieve fusion in many, many ways. The problem is getting any energy out and doing so at a meaningful scale. Something like ... the difference between folding a paper airplane and designing and building an airliner.
bell-cot 5y ago
Roughly speaking, the catch with every fusion-related "breakthrough" in the past 60+ years is the not-so-slight difference between: - "With a huge research budget, we found a nifty new way to reliably set a few tiny lumps of coal on fire in our lab." and - "We can reliably build useful and practical locomotives, ships, and electrical generating plants which are powered by burning coal...and are long-term economically viable in a world which has several other ways of powering locomotives, ships, and electrical generating plants." Except that with coal, making a far bigger fire is incredibly easy. With fusion, all the $Billions in the world don't seem capable of making even a modestly bigger...
- mcronce 5y ago
  Fusion research has not received anything even remotely resembling "all the $Billions in the world"
  - bell-cot 5y ago
    Literally you are correct - that phrase is a bit of English-language rhetoric. But neither has fusion power shown anything even remotely resembling the real-world promise of fission power - which went from the first major attempt at a proof-of-concept reactor (Chicago Pile-1, Dec. 1942, ~1/2 watt thermal power output) to powering a large, high-performance warship (USS Nautilus, Jan. 1955, ~10MW on the propeller shafts) in just 12 years.
- DennisP 5y ago
  Here's something modestly bigger: the UK's JET reactor recently produced 11 megawatts for five seconds. https://www.mpg.de/18250857/jet-fusion-facility-new-world-energy-record https://www.mpg.de/18250857/jet-fusion-facility-new-world-en... The plasma was stable and they could have gone longer except instead of superconductors, JET uses copper coils that would melt if they went longer. Their input energy was about three times their total output. But fusion output scales with the square of reactor volume and the fourth power of magnetic field strength, and modern REBCO superconductors can support much stronger fields than JET was using.
  - bell-cot 5y ago
    Wikipedia notes that JET produced 10MW of fusion power, sustained for 0.5 seconds, back in 1997. If that real-world rate of improvement continues, it'll reach 12MW for 50 seconds in 2047, and 13MW for 500 seconds in 2072. Meanwhile, a set of 5 30-year-old diesel-electric railroad locomotives can reliably put out ~10MW of usable electrical power (vs. thermal production). Vastly cheaper, with a proven track record and 100% duty cycle. (Generously figuring 3 running, 1 standby, 1 down for maintenance.) ( Wikipedia reference on JET: https://en.wikipedia.org/wiki/Fusion_power#1990s https://en.wikipedia.org/wiki/Fusion_power#1990s )
androa 5y ago
Short story, they are shooting small plastic cubes with gas inside. The cubes are called "targets". The "bullet" is fast enough to compress the gas inside the cube, creating fusion. It works. But in the scenario it does work, a machine is manually opened, loaded, prepared, and then they do the shot. Whole process takes days to prepare. For it to be viable they need to do this every five seconds. That is a hard problem to solve. First lights business model is not to solve that problem, but rather producing the "fuel", the tiny cubes with gas inside. They say there is many details in how they are built which increases efficiency. But someone still has to figure out how to build a machine that can continuously reload both the fuel and the bullet.
- oneoff786 5y ago
  Ok. So dumb question. What complicates this beyond a conceptual belt fed heavy machine gun?
  - Gene_Parmesan 5y ago
    > To deliver this fusion result, First Light used its large two-stage hyper-velocity gas gun to launch a projectile at a target, containing the fusion fuel. The projectile reached a speed of 6.5 km per second before impact. First Light’s highly sophisticated target focuses this impact, with the fuel accelerated to over 70 km per second as it implodes, an increase in velocity achieved through our proprietary advanced target design, making it the fastest moving object on earth at that point. Conceptually, maybe nothing, but we aren't really talking about your average MG-42 here.
  - skykooler 5y ago
    For one thing, it's a light-gas gun - you don't just reload the projectile, you have to refill the hydrogen after each shot.

beefman 5y ago

They made 50 neutrons from this shot! You can make billions per second, steady state, with a tabletop device plugged into a standard outlet. Edit: Fusion makes ~ 10^15 neutrons for every watt-hour of energy released (for the easiest kind of fusion) https://www.wolframalpha.com/input/?i=1+Wh+%2F+17.6+MeV https://www.wolframalpha.com/input/?i=1+Wh+%2F+17.6+MeV

regularfry 5y ago

I can imagine the downsides of accelerating the fuel that hard at the target and missing might be fairly entertaining.

colechristensen 5y ago

The small print is that you can achieve fusion in many, many ways. The problem is getting any energy out and doing so at a meaningful scale. Something like ... the difference between folding a paper airplane and designing and building an airliner.

bell-cot 5y ago

Roughly speaking, the catch with every fusion-related "breakthrough" in the past 60+ years is the not-so-slight difference between: - "With a huge research budget, we found a nifty new way to reliably set a few tiny lumps of coal on fire in our lab." and - "We can reliably build useful and practical locomotives, ships, and electrical generating plants which are powered by burning coal...and are long-term economically viable in a world which has several other ways of powering locomotives, ships, and electrical generating plants." Except that with coal, making a far bigger fire is incredibly easy. With fusion, all the $Billions in the world don't seem capable of making even a modestly bigger...

mcronce 5y ago
Fusion research has not received anything even remotely resembling "all the $Billions in the world"
- bell-cot 5y ago
  Literally you are correct - that phrase is a bit of English-language rhetoric. But neither has fusion power shown anything even remotely resembling the real-world promise of fission power - which went from the first major attempt at a proof-of-concept reactor (Chicago Pile-1, Dec. 1942, ~1/2 watt thermal power output) to powering a large, high-performance warship (USS Nautilus, Jan. 1955, ~10MW on the propeller shafts) in just 12 years.
DennisP 5y ago
Here's something modestly bigger: the UK's JET reactor recently produced 11 megawatts for five seconds. https://www.mpg.de/18250857/jet-fusion-facility-new-world-energy-record https://www.mpg.de/18250857/jet-fusion-facility-new-world-en... The plasma was stable and they could have gone longer except instead of superconductors, JET uses copper coils that would melt if they went longer. Their input energy was about three times their total output. But fusion output scales with the square of reactor volume and the fourth power of magnetic field strength, and modern REBCO superconductors can support much stronger fields than JET was using.
- bell-cot 5y ago
  Wikipedia notes that JET produced 10MW of fusion power, sustained for 0.5 seconds, back in 1997. If that real-world rate of improvement continues, it'll reach 12MW for 50 seconds in 2047, and 13MW for 500 seconds in 2072. Meanwhile, a set of 5 30-year-old diesel-electric railroad locomotives can reliably put out ~10MW of usable electrical power (vs. thermal production). Vastly cheaper, with a proven track record and 100% duty cycle. (Generously figuring 3 running, 1 standby, 1 down for maintenance.) ( Wikipedia reference on JET: https://en.wikipedia.org/wiki/Fusion_power#1990s https://en.wikipedia.org/wiki/Fusion_power#1990s )

androa 5y ago

Short story, they are shooting small plastic cubes with gas inside. The cubes are called "targets". The "bullet" is fast enough to compress the gas inside the cube, creating fusion. It works. But in the scenario it does work, a machine is manually opened, loaded, prepared, and then they do the shot. Whole process takes days to prepare. For it to be viable they need to do this every five seconds. That is a hard problem to solve. First lights business model is not to solve that problem, but rather producing the "fuel", the tiny cubes with gas inside. They say there is many details in how they are built which increases efficiency. But someone still has to figure out how to build a machine that can continuously reload both the fuel and the bullet.

oneoff786 5y ago
Ok. So dumb question. What complicates this beyond a conceptual belt fed heavy machine gun?
- Gene_Parmesan 5y ago
  > To deliver this fusion result, First Light used its large two-stage hyper-velocity gas gun to launch a projectile at a target, containing the fusion fuel. The projectile reached a speed of 6.5 km per second before impact. First Light’s highly sophisticated target focuses this impact, with the fuel accelerated to over 70 km per second as it implodes, an increase in velocity achieved through our proprietary advanced target design, making it the fastest moving object on earth at that point. Conceptually, maybe nothing, but we aren't really talking about your average MG-42 here.
- skykooler 5y ago
  For one thing, it's a light-gas gun - you don't just reload the projectile, you have to refill the hydrogen after each shot.