3 ms·

This is like a version 1.0 steam engine. Miniaturization and optimization can come next.

jeffbee 4y ago
The analogy doesn't really work. The utility of a steam engine was obvious to antiquity, but they did not have the materials technology to build it. They did not need basic science to do steam power. The first practical steam engine predates the understanding by chemists of combustion. It was invented when phlogiston was still the going theory. NIF on the other hand is already a miracle of materials science. An absolute triumph. But you can't enumerate the list of unsolved problems that, if eventually solved, lead to inertial confinement fusion as a civilian energy source. On the other side you can make that list for magnetic confinement. There is a clear path from magnetic confinement research to commercialization, with a known set of major problems.
- thehappypm 4y ago
  People in antiquity did build a functioning steam-powered engine, but dismissed it as a curiosity. https://en.wikipedia.org/wiki/Aeolipile https://en.wikipedia.org/wiki/Aeolipile
  - ufmace 4y ago
    This fascinating article goes into more detail on the reasons why: https://acoup.blog/2022/08/26/collections-why-no-roman-industrial-revolution/ https://acoup.blog/2022/08/26/collections-why-no-roman-indus... They correctly dismissed it as a curiosity because it was far too inefficient to do anything useful with the amounts of fuel they would have had available. They couldn't have made a more efficient one because they didn't have any idea how to construct reasonably uniform pressure-bearing cylinders. Real innovation didn't happen until much later on, at British coal mines because 1. there was lots of fuel because it's already at a coal mine, 2. there was a useful task for the work in pumping water out of the mine, and 3. materials technology had advanced enough to make it possible to construct an engine that did a useful amount of work from a manageable amount of fuel.
idlewords 4y ago
The problem is you can say that about any wildly inefficient new technology, but it doesn't always pan out.
tsimionescu 4y ago
No, this is like research into TNT being presented as a potential way of creating a power plant by capturing the energy of the explosion. The real purpose is producing better explosives. This is not some bizarre idea - Lawrence Livermore is officially a part of the DoE's research into maintaining and improving thermonuclear weapons. That there are some vaguely imaginable applications in energy generation is at the very best a bonus. Remember that each shot of the lasers also destroys 10 million dollars or so of the highly precision engineered "housing" for the fuel pellet (called a hohlraum). The lasers don't directly hit the pellet - they hit the metal walls of this hohlraum, causing it to grow so hot that it emits x-rays, and its shape is perfectly aligned so that those pellets hit the two sides of the pellet at exactly the same time, causing two "ripples" to compress it so much that they force the atoms to fuse in the middle and produce a chain reaction that has to consume the entire amount of fuel before the force of the implosion dissipates, at which time all of the matter violently explodes. The brunt of that explosion (and the neutron bombardment from the fusion process) is taken up by the hohlraum, which is ireedemably destroyed and can only be, at best, melted down as raw material for the next hohlraum. Edit: tldr, this is exactly as useful for energy generation as an internal combustion engine whose pistons are destroyed every time the fuel ignites.
- thehappypm 4y ago
  I’m not following exactly—are the lasers destroyed after each shot? The fuel being destroyed of course makes sense..
  - tsimionescu 4y ago
    No, the hohlraum is, which costs millions of dollars by itself. And it costs so much because it is essentially the piece that handles the synchronization of hitting the fuel pellet perfectly symmetrically. Its also built from solid gold right now, though depleted uranium may also work - either way, the raw material is only a fraction of the cost, the perfection required in achieving its exact shape is the problem.

The analogy doesn't really work. The utility of a steam engine was obvious to antiquity, but they did not have the materials technology to build it. They did not need basic science to do steam power. The first practical steam engine predates the understanding by chemists of combustion. It was invented when phlogiston was still the going theory. NIF on the other hand is already a miracle of materials science. An absolute triumph. But you can't enumerate the list of unsolved problems that, if eventually solved, lead to inertial confinement fusion as a civilian energy source. On the other side you can make that list for magnetic confinement. There is a clear path from magnetic confinement research to commercialization, with a known set of major problems.

thehappypm 4y ago
People in antiquity did build a functioning steam-powered engine, but dismissed it as a curiosity. https://en.wikipedia.org/wiki/Aeolipile https://en.wikipedia.org/wiki/Aeolipile
- ufmace 4y ago
  This fascinating article goes into more detail on the reasons why: https://acoup.blog/2022/08/26/collections-why-no-roman-industrial-revolution/ https://acoup.blog/2022/08/26/collections-why-no-roman-indus... They correctly dismissed it as a curiosity because it was far too inefficient to do anything useful with the amounts of fuel they would have had available. They couldn't have made a more efficient one because they didn't have any idea how to construct reasonably uniform pressure-bearing cylinders. Real innovation didn't happen until much later on, at British coal mines because 1. there was lots of fuel because it's already at a coal mine, 2. there was a useful task for the work in pumping water out of the mine, and 3. materials technology had advanced enough to make it possible to construct an engine that did a useful amount of work from a manageable amount of fuel.

idlewords 4y ago

The problem is you can say that about any wildly inefficient new technology, but it doesn't always pan out.

tsimionescu 4y ago

No, this is like research into TNT being presented as a potential way of creating a power plant by capturing the energy of the explosion. The real purpose is producing better explosives. This is not some bizarre idea - Lawrence Livermore is officially a part of the DoE's research into maintaining and improving thermonuclear weapons. That there are some vaguely imaginable applications in energy generation is at the very best a bonus. Remember that each shot of the lasers also destroys 10 million dollars or so of the highly precision engineered "housing" for the fuel pellet (called a hohlraum). The lasers don't directly hit the pellet - they hit the metal walls of this hohlraum, causing it to grow so hot that it emits x-rays, and its shape is perfectly aligned so that those pellets hit the two sides of the pellet at exactly the same time, causing two "ripples" to compress it so much that they force the atoms to fuse in the middle and produce a chain reaction that has to consume the entire amount of fuel before the force of the implosion dissipates, at which time all of the matter violently explodes. The brunt of that explosion (and the neutron bombardment from the fusion process) is taken up by the hohlraum, which is ireedemably destroyed and can only be, at best, melted down as raw material for the next hohlraum. Edit: tldr, this is exactly as useful for energy generation as an internal combustion engine whose pistons are destroyed every time the fuel ignites.

thehappypm 4y ago
I’m not following exactly—are the lasers destroyed after each shot? The fuel being destroyed of course makes sense..
- tsimionescu 4y ago
  No, the hohlraum is, which costs millions of dollars by itself. And it costs so much because it is essentially the piece that handles the synchronization of hitting the fuel pellet perfectly symmetrically. Its also built from solid gold right now, though depleted uranium may also work - either way, the raw material is only a fraction of the cost, the perfection required in achieving its exact shape is the problem.